Merge branch 'dev-v2' into dev-v2

RELEASENOTES.md

@@ -5,15 +5,37 @@
 * Support for playing spherical videos on Daydream.
 * Improve decoder re-use between playbacks. TODO: Write and link a blog post
   here ([#2826](https://github.com/google/ExoPlayer/issues/2826)).
-* Add options for controlling audio track selections to `DefaultTrackSelector`
-  ([#3314](https://github.com/google/ExoPlayer/issues/3314)).
+* Track selection:
+  * Add options for controlling audio track selections to `DefaultTrackSelector`
+    ([#3314](https://github.com/google/ExoPlayer/issues/3314)).
+  * Update `TrackSelection.Factory` interface to support creating all track
+    selections together.
+* Captions:
+  * Support PNG subtitles in SMPTE-TT
+    ([#1583](https://github.com/google/ExoPlayer/issues/1583)).
 * Do not retry failed loads whose error is `FileNotFoundException`.
-* Prevent Cea608Decoder from generating Subtitles with null Cues list
-* Caching: Cache data with unknown length by default. The previous flag to opt in
-  to this behavior (`DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH`) has been
-  replaced with an opt out flag (`DataSpec.FLAG_DONT_CACHE_IF_LENGTH_UNKNOWN`).
+* Prevent Cea608Decoder from generating Subtitles with null Cues list.
+* Offline:
+  * Speed up removal of segmented downloads
+    ([#5136](https://github.com/google/ExoPlayer/issues/5136)).
+  * Add `setStreamKeys` method to factories of DASH, SmoothStreaming and HLS
+    media sources to simplify filtering by downloaded streams.
+* Caching:
+  * Improve performance of `SimpleCache`.
+  * Cache data with unknown length by default. The previous flag to opt in to
+    this behavior (`DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH`) has been
+    replaced with an opt out flag
+    (`DataSpec.FLAG_DONT_CACHE_IF_LENGTH_UNKNOWN`).
+* Disable post processing on Nvidia devices, as it breaks decode-only frame
+  skippping.
+* Workaround for MiTV (dangal) issue when swapping output surface
+  ([#5169](https://github.com/google/ExoPlayer/issues/5169)).
+* DownloadManager:
+  * Create only one task for all DownloadActions for the same content.
+  * Rename TaskState to DownloadState.
 * MP3: Fix issue where streams would play twice on Samsung devices
   ([#4519](https://github.com/google/ExoPlayer/issues/4519)).
+
 ### 2.9.2 ###
 
 * HLS:
@@ -61,10 +83,10 @@
 * DASH: Parse ProgramInformation element if present in the manifest.
 * HLS:
   * Add constructor to `DefaultHlsExtractorFactory` for adding TS payload
-    reader factory flags.
+    reader factory flags
+    ([#4861](https://github.com/google/ExoPlayer/issues/4861)).
   * Fix bug in segment sniffing
     ([#5039](https://github.com/google/ExoPlayer/issues/5039)).
-  ([#4861](https://github.com/google/ExoPlayer/issues/4861)).
 * SubRip: Add support for alignment tags, and remove tags from the displayed
   captions ([#4306](https://github.com/google/ExoPlayer/issues/4306)).
 * Fix issue with blind seeking to windows with non-zero offset in a

demos/cast/build.gradle

@@ -49,6 +49,16 @@ android {
         disable 'MissingTranslation'
     }
 
+    flavorDimensions "receiver"
+
+    productFlavors {
+        defaultCast {
+            dimension "receiver"
+            manifestPlaceholders =
+                    [castOptionsProvider: "com.google.android.exoplayer2.ext.cast.DefaultCastOptionsProvider"]
+        }
+    }
+
 }
 
 dependencies {

demos/cast/src/main/AndroidManifest.xml

@@ -23,7 +23,7 @@
       android:largeHeap="true" android:allowBackup="false">
 
     <meta-data android:name="com.google.android.gms.cast.framework.OPTIONS_PROVIDER_CLASS_NAME"
-        android:value="com.google.android.exoplayer2.ext.cast.DefaultCastOptionsProvider" />
+        android:value="${castOptionsProvider}" />
 
     <activity android:name="com.google.android.exoplayer2.castdemo.MainActivity"
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"

demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/DefaultReceiverPlayerManager.java

@@ -268,7 +268,7 @@ import java.util.ArrayList;
   public void onTimelineChanged(
       Timeline timeline, @Nullable Object manifest, @TimelineChangeReason int reason) {
     updateCurrentItemIndex();
-    if (timeline.isEmpty()) {
+    if (currentPlayer == castPlayer && timeline.isEmpty()) {
       castMediaQueueCreationPending = true;
     }
   }

demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/DemoUtil.java

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.castdemo;
 
-import com.google.android.exoplayer2.ext.cast.MediaItem;
 import com.google.android.exoplayer2.util.MimeTypes;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -24,50 +23,64 @@ import java.util.List;
 /** Utility methods and constants for the Cast demo application. */
 /* package */ final class DemoUtil {
 
+  /** Represents a media sample. */
+  public static final class Sample {
+
+    /** The uri of the media content. */
+    public final String uri;
+    /** The name of the sample. */
+    public final String name;
+    /** The mime type of the sample media content. */
+    public final String mimeType;
+
+    /**
+     * @param uri See {@link #uri}.
+     * @param name See {@link #name}.
+     * @param mimeType See {@link #mimeType}.
+     */
+    public Sample(String uri, String name, String mimeType) {
+      this.uri = uri;
+      this.name = name;
+      this.mimeType = mimeType;
+    }
+
+    @Override
+    public String toString() {
+      return name;
+    }
+  }
+
   public static final String MIME_TYPE_DASH = MimeTypes.APPLICATION_MPD;
   public static final String MIME_TYPE_HLS = MimeTypes.APPLICATION_M3U8;
   public static final String MIME_TYPE_SS = MimeTypes.APPLICATION_SS;
   public static final String MIME_TYPE_VIDEO_MP4 = MimeTypes.VIDEO_MP4;
 
   /** The list of samples available in the cast demo app. */
-  public static final List<MediaItem> SAMPLES;
+  public static final List<Sample> SAMPLES;
 
   static {
     // App samples.
-    ArrayList<MediaItem> samples = new ArrayList<>();
-    MediaItem.Builder sampleBuilder = new MediaItem.Builder();
+    ArrayList<Sample> samples = new ArrayList<>();
 
     samples.add(
-        sampleBuilder
-            .setTitle("DASH (clear,MP4,H264)")
-            .setMimeType(MIME_TYPE_DASH)
-            .setMedia("https://storage.googleapis.com/wvmedia/clear/h264/tears/tears.mpd")
-            .buildAndClear());
-
+        new Sample(
+            "https://storage.googleapis.com/wvmedia/clear/h264/tears/tears.mpd",
+            "DASH (clear,MP4,H264)",
+            MIME_TYPE_DASH));
     samples.add(
-        sampleBuilder
-            .setTitle("Tears of Steel (HLS)")
-            .setMimeType(MIME_TYPE_HLS)
-            .setMedia(
-                "https://commondatastorage.googleapis.com/gtv-videos-bucket/CastVideos/"
-                    + "hls/TearsOfSteel.m3u8")
-            .buildAndClear());
-
+        new Sample(
+            "https://commondatastorage.googleapis.com/gtv-videos-bucket/CastVideos/"
+                + "hls/TearsOfSteel.m3u8",
+            "Tears of Steel (HLS)",
+            MIME_TYPE_HLS));
     samples.add(
-        sampleBuilder
-            .setTitle("HLS Basic (TS)")
-            .setMimeType(MIME_TYPE_HLS)
-            .setMedia(
-                "https://devstreaming-cdn.apple.com/videos/streaming/examples/bipbop_4x3"
-                    + "/bipbop_4x3_variant.m3u8")
-            .buildAndClear());
-
+        new Sample(
+            "https://devstreaming-cdn.apple.com/videos/streaming/examples/bipbop_4x3"
+                + "/bipbop_4x3_variant.m3u8",
+            "HLS Basic (TS)",
+            MIME_TYPE_HLS));
     samples.add(
-        sampleBuilder
-            .setTitle("Dizzy (MP4)")
-            .setMimeType(MIME_TYPE_VIDEO_MP4)
-            .setMedia("https://html5demos.com/assets/dizzy.mp4")
-            .buildAndClear());
+        new Sample("https://html5demos.com/assets/dizzy.mp4", "Dizzy (MP4)", MIME_TYPE_VIDEO_MP4));
     SAMPLES = Collections.unmodifiableList(samples);
   }
 

demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/MainActivity.java

@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.castdemo;
 
 import android.content.Context;
 import android.os.Bundle;
-import android.support.annotation.Nullable;
 import android.support.v4.graphics.ColorUtils;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.app.AppCompatActivity;
@@ -50,6 +49,8 @@ import com.google.android.gms.cast.framework.CastContext;
 public class MainActivity extends AppCompatActivity
     implements OnClickListener, PlayerManager.QueuePositionListener {
 
+  private final MediaItem.Builder mediaItemBuilder;
+
   private PlayerView localPlayerView;
   private PlayerControlView castControlView;
   private PlayerManager playerManager;
@@ -57,6 +58,10 @@ public class MainActivity extends AppCompatActivity
   private MediaQueueListAdapter mediaQueueListAdapter;
   private CastContext castContext;
 
+  public MainActivity() {
+    mediaItemBuilder = new MediaItem.Builder();
+  }
+
   // Activity lifecycle methods.
 
   @Override
@@ -154,7 +159,14 @@ public class MainActivity extends AppCompatActivity
     sampleList.setAdapter(new SampleListAdapter(this));
     sampleList.setOnItemClickListener(
         (parent, view, position, id) -> {
-          playerManager.addItem(DemoUtil.SAMPLES.get(position));
+          DemoUtil.Sample sample = DemoUtil.SAMPLES.get(position);
+          playerManager.addItem(
+              mediaItemBuilder
+                  .clear()
+                  .setMedia(sample.uri)
+                  .setTitle(sample.name)
+                  .setMimeType(sample.mimeType)
+                  .build());
           mediaQueueListAdapter.notifyItemInserted(playerManager.getMediaQueueSize() - 1);
         });
     return dialogList;
@@ -254,19 +266,11 @@ public class MainActivity extends AppCompatActivity
 
   }
 
-  private static final class SampleListAdapter extends ArrayAdapter<MediaItem> {
+  private static final class SampleListAdapter extends ArrayAdapter<DemoUtil.Sample> {
 
     public SampleListAdapter(Context context) {
       super(context, android.R.layout.simple_list_item_1, DemoUtil.SAMPLES);
     }
-
-    @Override
-    public View getView(int position, @Nullable View convertView, ViewGroup parent) {
-      TextView view = (TextView) super.getView(position, convertView, parent);
-      MediaItem sample = DemoUtil.SAMPLES.get(position);
-      view.setText(sample.title);
-      return view;
-    }
   }
 
 }

demos/main/src/main/java/com/google/android/exoplayer2/demo/DemoApplication.java

@@ -16,6 +16,8 @@
 package com.google.android.exoplayer2.demo;
 
 import android.app.Application;
+import com.google.android.exoplayer2.DefaultRenderersFactory;
+import com.google.android.exoplayer2.RenderersFactory;
 import com.google.android.exoplayer2.offline.DefaultDownloaderFactory;
 import com.google.android.exoplayer2.offline.DownloadManager;
 import com.google.android.exoplayer2.offline.DownloaderConstructorHelper;
@@ -72,6 +74,17 @@ public class DemoApplication extends Application {
     return "withExtensions".equals(BuildConfig.FLAVOR);
   }
 
+  public RenderersFactory buildRenderersFactory(boolean preferExtensionRenderer) {
+    @DefaultRenderersFactory.ExtensionRendererMode
+    int extensionRendererMode =
+        useExtensionRenderers()
+            ? (preferExtensionRenderer
+                ? DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER
+                : DefaultRenderersFactory.EXTENSION_RENDERER_MODE_ON)
+            : DefaultRenderersFactory.EXTENSION_RENDERER_MODE_OFF;
+    return new DefaultRenderersFactory(this, extensionRendererMode);
+  }
+
   public DownloadManager getDownloadManager() {
     initDownloadManager();
     return downloadManager;

demos/main/src/main/java/com/google/android/exoplayer2/demo/DemoDownloadService.java

@@ -17,7 +17,7 @@ package com.google.android.exoplayer2.demo;
 
 import android.app.Notification;
 import com.google.android.exoplayer2.offline.DownloadManager;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 import com.google.android.exoplayer2.offline.DownloadService;
 import com.google.android.exoplayer2.scheduler.PlatformScheduler;
 import com.google.android.exoplayer2.ui.DownloadNotificationUtil;
@@ -31,12 +31,15 @@ public class DemoDownloadService extends DownloadService {
   private static final int JOB_ID = 1;
   private static final int FOREGROUND_NOTIFICATION_ID = 1;
 
+  private static int nextNotificationId = FOREGROUND_NOTIFICATION_ID + 1;
+
   public DemoDownloadService() {
     super(
         FOREGROUND_NOTIFICATION_ID,
         DEFAULT_FOREGROUND_NOTIFICATION_UPDATE_INTERVAL,
         CHANNEL_ID,
         R.string.exo_download_notification_channel_name);
+    nextNotificationId = FOREGROUND_NOTIFICATION_ID + 1;
   }
 
   @Override
@@ -50,40 +53,41 @@ public class DemoDownloadService extends DownloadService {
   }
 
   @Override
-  protected Notification getForegroundNotification(TaskState[] taskStates) {
+  protected Notification getForegroundNotification(DownloadState[] downloadStates) {
     return DownloadNotificationUtil.buildProgressNotification(
         /* context= */ this,
-        R.drawable.exo_controls_play,
+        R.drawable.ic_download,
         CHANNEL_ID,
         /* contentIntent= */ null,
         /* message= */ null,
-        taskStates);
+        downloadStates);
   }
 
   @Override
-  protected void onTaskStateChanged(TaskState taskState) {
-    if (taskState.action.isRemoveAction) {
+  protected void onDownloadStateChanged(DownloadState downloadState) {
+    if (downloadState.action.isRemoveAction) {
       return;
     }
     Notification notification = null;
-    if (taskState.state == TaskState.STATE_COMPLETED) {
+    if (downloadState.state == DownloadState.STATE_COMPLETED) {
       notification =
           DownloadNotificationUtil.buildDownloadCompletedNotification(
               /* context= */ this,
-              R.drawable.exo_controls_play,
+              R.drawable.ic_download_done,
               CHANNEL_ID,
               /* contentIntent= */ null,
-              Util.fromUtf8Bytes(taskState.action.data));
-    } else if (taskState.state == TaskState.STATE_FAILED) {
+              Util.fromUtf8Bytes(downloadState.action.data));
+    } else if (downloadState.state == DownloadState.STATE_FAILED) {
       notification =
           DownloadNotificationUtil.buildDownloadFailedNotification(
               /* context= */ this,
-              R.drawable.exo_controls_play,
+              R.drawable.ic_download_done,
               CHANNEL_ID,
               /* contentIntent= */ null,
-              Util.fromUtf8Bytes(taskState.action.data));
+              Util.fromUtf8Bytes(downloadState.action.data));
+    } else {
+      return;
     }
-    int notificationId = FOREGROUND_NOTIFICATION_ID + 1 + taskState.taskId;
-    NotificationUtil.setNotification(this, notificationId, notification);
+    NotificationUtil.setNotification(this, nextNotificationId++, notification);
   }
 }

demos/main/src/main/java/com/google/android/exoplayer2/demo/DownloadTracker.java

@@ -19,37 +19,43 @@ import android.app.Activity;
 import android.app.AlertDialog;
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.res.Resources;
 import android.net.Uri;
 import android.os.Handler;
 import android.os.HandlerThread;
+import android.support.annotation.Nullable;
+import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.widget.ArrayAdapter;
-import android.widget.ListView;
+import android.widget.ImageButton;
+import android.widget.LinearLayout;
+import android.widget.TextView;
 import android.widget.Toast;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.RenderersFactory;
 import com.google.android.exoplayer2.offline.ActionFile;
 import com.google.android.exoplayer2.offline.DownloadAction;
 import com.google.android.exoplayer2.offline.DownloadHelper;
 import com.google.android.exoplayer2.offline.DownloadManager;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 import com.google.android.exoplayer2.offline.DownloadService;
 import com.google.android.exoplayer2.offline.ProgressiveDownloadHelper;
 import com.google.android.exoplayer2.offline.StreamKey;
-import com.google.android.exoplayer2.offline.TrackKey;
-import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.dash.offline.DashDownloadHelper;
 import com.google.android.exoplayer2.source.hls.offline.HlsDownloadHelper;
 import com.google.android.exoplayer2.source.smoothstreaming.offline.SsDownloadHelper;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
+import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
+import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.ui.DefaultTrackNameProvider;
 import com.google.android.exoplayer2.ui.TrackNameProvider;
+import com.google.android.exoplayer2.ui.TrackSelectionView;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.Util;
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -114,14 +120,19 @@ public class DownloadTracker implements DownloadManager.Listener {
     return trackedDownloadStates.get(uri).getKeys();
   }
 
-  public void toggleDownload(Activity activity, String name, Uri uri, String extension) {
+  public void toggleDownload(
+      Activity activity,
+      String name,
+      Uri uri,
+      String extension,
+      RenderersFactory renderersFactory) {
     if (isDownloaded(uri)) {
-      DownloadAction removeAction = getDownloadHelper(uri, extension).getRemoveAction();
+      DownloadAction removeAction =
+          getDownloadHelper(uri, extension, renderersFactory).getRemoveAction();
       startServiceWithAction(removeAction);
     } else {
-      StartDownloadDialogHelper helper =
-          new StartDownloadDialogHelper(activity, getDownloadHelper(uri, extension), name);
-      helper.prepare();
+      new StartDownloadDialogHelper(
+          activity, getDownloadHelper(uri, extension, renderersFactory), name);
     }
   }
 
@@ -133,11 +144,11 @@ public class DownloadTracker implements DownloadManager.Listener {
   }
 
   @Override
-  public void onTaskStateChanged(DownloadManager downloadManager, TaskState taskState) {
-    DownloadAction action = taskState.action;
+  public void onDownloadStateChanged(DownloadManager downloadManager, DownloadState downloadState) {
+    DownloadAction action = downloadState.action;
     Uri uri = action.uri;
-    if ((action.isRemoveAction && taskState.state == TaskState.STATE_COMPLETED)
-        || (!action.isRemoveAction && taskState.state == TaskState.STATE_FAILED)) {
+    if ((action.isRemoveAction && downloadState.state == DownloadState.STATE_COMPLETED)
+        || (!action.isRemoveAction && downloadState.state == DownloadState.STATE_FAILED)) {
       // A download has been removed, or has failed. Stop tracking it.
       if (trackedDownloadStates.remove(uri) != null) {
         handleTrackedDownloadStatesChanged();
@@ -192,15 +203,16 @@ public class DownloadTracker implements DownloadManager.Listener {
     DownloadService.startWithAction(context, DemoDownloadService.class, action, false);
   }
 
-  private DownloadHelper getDownloadHelper(Uri uri, String extension) {
+  private DownloadHelper<?> getDownloadHelper(
+      Uri uri, String extension, RenderersFactory renderersFactory) {
     int type = Util.inferContentType(uri, extension);
     switch (type) {
       case C.TYPE_DASH:
-        return new DashDownloadHelper(uri, dataSourceFactory);
+        return new DashDownloadHelper(uri, dataSourceFactory, renderersFactory);
       case C.TYPE_SS:
-        return new SsDownloadHelper(uri, dataSourceFactory);
+        return new SsDownloadHelper(uri, dataSourceFactory, renderersFactory);
       case C.TYPE_HLS:
-        return new HlsDownloadHelper(uri, dataSourceFactory);
+        return new HlsDownloadHelper(uri, dataSourceFactory, renderersFactory);
       case C.TYPE_OTHER:
         return new ProgressiveDownloadHelper(uri);
       default:
@@ -208,84 +220,165 @@ public class DownloadTracker implements DownloadManager.Listener {
     }
   }
 
+  @SuppressWarnings("UngroupedOverloads")
   private final class StartDownloadDialogHelper
-      implements DownloadHelper.Callback, DialogInterface.OnClickListener {
+      implements DownloadHelper.Callback,
+          DialogInterface.OnClickListener,
+          View.OnClickListener,
+          TrackSelectionView.DialogCallback {
 
-    private final DownloadHelper downloadHelper;
+    private final DownloadHelper<?> downloadHelper;
     private final String name;
+    private final LayoutInflater dialogInflater;
+    private final AlertDialog dialog;
+    private final LinearLayout selectionList;
 
-    private final AlertDialog.Builder builder;
-    private final View dialogView;
-    private final List<TrackKey> trackKeys;
-    private final ArrayAdapter<String> trackTitles;
-    private final ListView representationList;
+    private MappedTrackInfo mappedTrackInfo;
+    private DefaultTrackSelector.Parameters parameters;
 
-    public StartDownloadDialogHelper(
-        Activity activity, DownloadHelper downloadHelper, String name) {
+    private StartDownloadDialogHelper(
+        Activity activity, DownloadHelper<?> downloadHelper, String name) {
       this.downloadHelper = downloadHelper;
       this.name = name;
-      builder =
+      AlertDialog.Builder builder =
           new AlertDialog.Builder(activity)
-              .setTitle(R.string.exo_download_description)
+              .setTitle(R.string.download_preparing)
               .setPositiveButton(android.R.string.ok, this)
               .setNegativeButton(android.R.string.cancel, null);
 
       // Inflate with the builder's context to ensure the correct style is used.
-      LayoutInflater dialogInflater = LayoutInflater.from(builder.getContext());
-      dialogView = dialogInflater.inflate(R.layout.start_download_dialog, null);
+      dialogInflater = LayoutInflater.from(builder.getContext());
+      selectionList = (LinearLayout) dialogInflater.inflate(R.layout.start_download_dialog, null);
+      builder.setView(selectionList);
+      dialog = builder.create();
+      dialog.show();
+      dialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(false);
 
-      trackKeys = new ArrayList<>();
-      trackTitles =
-          new ArrayAdapter<>(
-              builder.getContext(), android.R.layout.simple_list_item_multiple_choice);
-      representationList = dialogView.findViewById(R.id.representation_list);
-      representationList.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
-      representationList.setAdapter(trackTitles);
-    }
-
-    public void prepare() {
+      parameters = DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS;
       downloadHelper.prepare(this);
     }
 
+    // DownloadHelper.Callback implementation.
+
     @Override
-    public void onPrepared(DownloadHelper helper) {
-      for (int i = 0; i < downloadHelper.getPeriodCount(); i++) {
-        TrackGroupArray trackGroups = downloadHelper.getTrackGroups(i);
-        for (int j = 0; j < trackGroups.length; j++) {
-          TrackGroup trackGroup = trackGroups.get(j);
-          for (int k = 0; k < trackGroup.length; k++) {
-            trackKeys.add(new TrackKey(i, j, k));
-            trackTitles.add(trackNameProvider.getTrackName(trackGroup.getFormat(k)));
-          }
-        }
+    public void onPrepared(DownloadHelper<?> helper) {
+      if (helper.getPeriodCount() < 1) {
+        onPrepareError(downloadHelper, new IOException("Content is empty."));
+        return;
       }
-      if (!trackKeys.isEmpty()) {
-        builder.setView(dialogView);
-      }
-      builder.create().show();
+      mappedTrackInfo = downloadHelper.getMappedTrackInfo(/* periodIndex= */ 0);
+      updateSelectionList();
+      dialog.setTitle(R.string.exo_download_description);
+      dialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(true);
     }
 
     @Override
-    public void onPrepareError(DownloadHelper helper, IOException e) {
+    public void onPrepareError(DownloadHelper<?> helper, IOException e) {
       Toast.makeText(
               context.getApplicationContext(), R.string.download_start_error, Toast.LENGTH_LONG)
           .show();
       Log.e(TAG, "Failed to start download", e);
+      dialog.cancel();
     }
 
+    // View.OnClickListener implementation.
+
+    @Override
+    public void onClick(View v) {
+      Integer rendererIndex = (Integer) v.getTag();
+      String dialogTitle = getTrackTypeString(mappedTrackInfo.getRendererType(rendererIndex));
+      Pair<AlertDialog, TrackSelectionView> dialogPair =
+          TrackSelectionView.getDialog(
+              dialog.getContext(),
+              dialogTitle,
+              mappedTrackInfo,
+              rendererIndex,
+              parameters,
+              /* callback= */ this);
+      dialogPair.second.setShowDisableOption(true);
+      dialogPair.second.setAllowAdaptiveSelections(false);
+      dialogPair.first.show();
+    }
+
+    // TrackSelectionView.DialogCallback implementation.
+
+    @Override
+    public void onTracksSelected(DefaultTrackSelector.Parameters parameters) {
+      for (int i = 0; i < downloadHelper.getPeriodCount(); i++) {
+        downloadHelper.replaceTrackSelections(/* periodIndex= */ i, parameters);
+      }
+      this.parameters = parameters;
+      updateSelectionList();
+    }
+
+    // DialogInterface.OnClickListener implementation.
+
     @Override
     public void onClick(DialogInterface dialog, int which) {
-      ArrayList<TrackKey> selectedTrackKeys = new ArrayList<>();
-      for (int i = 0; i < representationList.getChildCount(); i++) {
-        if (representationList.isItemChecked(i)) {
-          selectedTrackKeys.add(trackKeys.get(i));
+      DownloadAction downloadAction = downloadHelper.getDownloadAction(Util.getUtf8Bytes(name));
+      startDownload(downloadAction);
+    }
+
+    // Internal methods.
+
+    private void updateSelectionList() {
+      selectionList.removeAllViews();
+      for (int i = 0; i < mappedTrackInfo.getRendererCount(); i++) {
+        TrackGroupArray trackGroupArray = mappedTrackInfo.getTrackGroups(i);
+        if (trackGroupArray.length == 0) {
+          continue;
+        }
+        String trackTypeString =
+            getTrackTypeString(mappedTrackInfo.getRendererType(/* rendererIndex= */ i));
+        if (trackTypeString == null) {
+          return;
+        }
+        String trackSelectionsString = getTrackSelectionString(/* rendererIndex= */ i);
+        View view = dialogInflater.inflate(R.layout.download_track_item, selectionList, false);
+        TextView trackTitleView = view.findViewById(R.id.track_title);
+        TextView trackDescView = view.findViewById(R.id.track_desc);
+        ImageButton editButton = view.findViewById(R.id.edit_button);
+        trackTitleView.setText(trackTypeString);
+        trackDescView.setText(trackSelectionsString);
+        editButton.setTag(i);
+        editButton.setOnClickListener(this);
+        selectionList.addView(view);
+      }
+    }
+
+    private String getTrackSelectionString(int rendererIndex) {
+      List<TrackSelection> trackSelections =
+          downloadHelper.getTrackSelections(/* periodIndex= */ 0, rendererIndex);
+      String selectedTracks = "";
+      Resources resources = selectionList.getResources();
+      for (int i = 0; i < trackSelections.size(); i++) {
+        TrackSelection selection = trackSelections.get(i);
+        for (int j = 0; j < selection.length(); j++) {
+          String trackName = trackNameProvider.getTrackName(selection.getFormat(j));
+          if (i == 0 && j == 0) {
+            selectedTracks = trackName;
+          } else {
+            selectedTracks = resources.getString(R.string.exo_item_list, selectedTracks, trackName);
+          }
         }
       }
-      if (!selectedTrackKeys.isEmpty() || trackKeys.isEmpty()) {
-        // We have selected keys, or we're dealing with single stream content.
-        DownloadAction downloadAction =
-            downloadHelper.getDownloadAction(Util.getUtf8Bytes(name), selectedTrackKeys);
-        startDownload(downloadAction);
+      return selectedTracks.isEmpty()
+          ? resources.getString(R.string.exo_track_selection_none)
+          : selectedTracks;
+    }
+
+    @Nullable
+    private String getTrackTypeString(int trackType) {
+      Resources resources = selectionList.getResources();
+      switch (trackType) {
+        case C.TRACK_TYPE_VIDEO:
+          return resources.getString(R.string.exo_track_selection_title_video);
+        case C.TRACK_TYPE_AUDIO:
+          return resources.getString(R.string.exo_track_selection_title_audio);
+        case C.TRACK_TYPE_TEXT:
+          return resources.getString(R.string.exo_track_selection_title_text);
+        default:
+          return null;
       }
     }
   }

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -35,11 +35,11 @@ import android.widget.TextView;
 import android.widget.Toast;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C.ContentType;
-import com.google.android.exoplayer2.DefaultRenderersFactory;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.ExoPlayerFactory;
 import com.google.android.exoplayer2.PlaybackPreparer;
 import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.RenderersFactory;
 import com.google.android.exoplayer2.SimpleExoPlayer;
 import com.google.android.exoplayer2.drm.DefaultDrmSessionManager;
 import com.google.android.exoplayer2.drm.FrameworkMediaCrypto;
@@ -48,7 +48,6 @@ import com.google.android.exoplayer2.drm.HttpMediaDrmCallback;
 import com.google.android.exoplayer2.drm.UnsupportedDrmException;
 import com.google.android.exoplayer2.mediacodec.MediaCodecRenderer.DecoderInitializationException;
 import com.google.android.exoplayer2.mediacodec.MediaCodecUtil.DecoderQueryException;
-import com.google.android.exoplayer2.offline.FilteringManifestParser;
 import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.BehindLiveWindowException;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
@@ -58,11 +57,8 @@ import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.ads.AdsLoader;
 import com.google.android.exoplayer2.source.ads.AdsMediaSource;
 import com.google.android.exoplayer2.source.dash.DashMediaSource;
-import com.google.android.exoplayer2.source.dash.manifest.DashManifestParser;
 import com.google.android.exoplayer2.source.hls.HlsMediaSource;
-import com.google.android.exoplayer2.source.hls.playlist.DefaultHlsPlaylistParserFactory;
 import com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource;
-import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifestParser;
 import com.google.android.exoplayer2.trackselection.AdaptiveTrackSelection;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
@@ -416,13 +412,8 @@ public class PlayerActivity extends Activity
 
       boolean preferExtensionDecoders =
           intent.getBooleanExtra(PREFER_EXTENSION_DECODERS_EXTRA, false);
-      @DefaultRenderersFactory.ExtensionRendererMode int extensionRendererMode =
-          ((DemoApplication) getApplication()).useExtensionRenderers()
-              ? (preferExtensionDecoders ? DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER
-              : DefaultRenderersFactory.EXTENSION_RENDERER_MODE_ON)
-              : DefaultRenderersFactory.EXTENSION_RENDERER_MODE_OFF;
-      DefaultRenderersFactory renderersFactory =
-          new DefaultRenderersFactory(this, extensionRendererMode);
+      RenderersFactory renderersFactory =
+          ((DemoApplication) getApplication()).buildRenderersFactory(preferExtensionDecoders);
 
       trackSelector = new DefaultTrackSelector(trackSelectionFactory);
       trackSelector.setParameters(trackSelectorParameters);
@@ -477,21 +468,19 @@ public class PlayerActivity extends Activity
   @SuppressWarnings("unchecked")
   private MediaSource buildMediaSource(Uri uri, @Nullable String overrideExtension) {
     @ContentType int type = Util.inferContentType(uri, overrideExtension);
+    List<StreamKey> offlineStreamKeys = getOfflineStreamKeys(uri);
     switch (type) {
       case C.TYPE_DASH:
         return new DashMediaSource.Factory(dataSourceFactory)
-            .setManifestParser(
-                new FilteringManifestParser<>(new DashManifestParser(), getOfflineStreamKeys(uri)))
+            .setStreamKeys(offlineStreamKeys)
             .createMediaSource(uri);
       case C.TYPE_SS:
         return new SsMediaSource.Factory(dataSourceFactory)
-            .setManifestParser(
-                new FilteringManifestParser<>(new SsManifestParser(), getOfflineStreamKeys(uri)))
+            .setStreamKeys(offlineStreamKeys)
             .createMediaSource(uri);
       case C.TYPE_HLS:
         return new HlsMediaSource.Factory(dataSourceFactory)
-            .setPlaylistParserFactory(
-                new DefaultHlsPlaylistParserFactory(getOfflineStreamKeys(uri)))
+            .setStreamKeys(offlineStreamKeys)
             .createMediaSource(uri);
       case C.TYPE_OTHER:
         return new ExtractorMediaSource.Factory(dataSourceFactory).createMediaSource(uri);

demos/main/src/main/java/com/google/android/exoplayer2/demo/SampleChooserActivity.java

@@ -37,6 +37,7 @@ import android.widget.ImageButton;
 import android.widget.TextView;
 import android.widget.Toast;
 import com.google.android.exoplayer2.ParserException;
+import com.google.android.exoplayer2.RenderersFactory;
 import com.google.android.exoplayer2.offline.DownloadService;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSourceInputStream;
@@ -177,7 +178,11 @@ public class SampleChooserActivity extends Activity
           .show();
     } else {
       UriSample uriSample = (UriSample) sample;
-      downloadTracker.toggleDownload(this, sample.name, uriSample.uri, uriSample.extension);
+      RenderersFactory renderersFactory =
+          ((DemoApplication) getApplication())
+              .buildRenderersFactory(isNonNullAndChecked(preferExtensionDecodersMenuItem));
+      downloadTracker.toggleDownload(
+          this, sample.name, uriSample.uri, uriSample.extension, renderersFactory);
     }
   }
 

demos/main/src/main/res/layout/download_track_item.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2018 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:paddingStart="12dp"
+    android:paddingEnd="12dp"
+    android:orientation="horizontal"
+    android:gravity="center_vertical">
+
+  <LinearLayout
+      android:layout_width="0dp"
+      android:layout_height="wrap_content"
+      android:layout_weight="1"
+      android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/track_title"
+        android:textStyle="bold"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:paddingTop="4dp"/>
+
+    <TextView
+        android:id="@+id/track_desc"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:paddingBottom="4dp"/>
+
+  </LinearLayout>
+
+  <ImageButton
+      android:id="@+id/edit_button"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"
+      android:background="@android:color/transparent"
+      android:contentDescription="@string/download_edit_track"
+      android:src="@drawable/ic_edit"/>
+
+</LinearLayout>

demos/main/src/main/res/layout/start_download_dialog.xml

@@ -13,7 +13,8 @@
      See the License for the specific language governing permissions and
      limitations under the License.
 -->
-<ListView xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/representation_list"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/selection_list"
+    android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent"/>

demos/main/src/main/res/values/strings.xml

@@ -51,6 +51,10 @@
 
   <string name="ima_not_loaded">Playing sample without ads, as the IMA extension was not loaded</string>
 
+  <string name="download_edit_track">Edit selection</string>
+
+  <string name="download_preparing">Preparing download…</string>
+
   <string name="download_start_error">Failed to start download</string>
 
   <string name="download_playlist_unsupported">This demo app does not support downloading playlists</string>

extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/TimelineQueueEditor.java

@@ -65,13 +65,6 @@ public final class TimelineQueueEditor
    * {@link MediaSessionConnector}.
    */
   public interface QueueDataAdapter {
-    /**
-     * Gets the {@link MediaDescriptionCompat} for a {@code position}.
-     *
-     * @param position The position in the queue for which to provide a description.
-     * @return A {@link MediaDescriptionCompat}.
-     */
-    MediaDescriptionCompat getMediaDescription(int position);
     /**
      * Adds a {@link MediaDescriptionCompat} at the given {@code position}.
      *

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecRenderer.java

@@ -1693,7 +1693,8 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
    */
   private static boolean codecNeedsEosFlushWorkaround(String name) {
     return (Util.SDK_INT <= 23 && "OMX.google.vorbis.decoder".equals(name))
-        || (Util.SDK_INT <= 19 && "hb2000".equals(Util.DEVICE)
+        || (Util.SDK_INT <= 19
+            && ("hb2000".equals(Util.DEVICE) || "stvm8".equals(Util.DEVICE))
             && ("OMX.amlogic.avc.decoder.awesome".equals(name)
                 || "OMX.amlogic.avc.decoder.awesome.secure".equals(name)));
   }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadAction.java

@@ -77,7 +77,7 @@ public final class DownloadAction {
    *
    * @param type The type of the action.
    * @param uri The URI of the media to be downloaded.
-   * @param keys Keys of tracks to be downloaded. If empty, all tracks will be downloaded.
+   * @param keys Keys of streams to be downloaded. If empty, all streams will be downloaded.
    * @param customCacheKey A custom key for cache indexing, or null.
    * @param data Optional custom data for this action. If {@code null} an empty array will be used.
    */
@@ -108,6 +108,8 @@ public final class DownloadAction {
         /* data= */ null);
   }
 
+  /** The unique content id. */
+  public final String id;
   /** The type of the action. */
   public final String type;
   /** The uri being downloaded or removed. */
@@ -115,8 +117,8 @@ public final class DownloadAction {
   /** Whether this is a remove action. If false, this is a download action. */
   public final boolean isRemoveAction;
   /**
-   * Keys of tracks to be downloaded. If empty, all tracks will be downloaded. Empty if this action
-   * is a remove action.
+   * Keys of streams to be downloaded. If empty, all streams will be downloaded. Empty if this
+   * action is a remove action.
    */
   public final List<StreamKey> keys;
   /** A custom key for cache indexing, or null. */
@@ -128,8 +130,8 @@ public final class DownloadAction {
    * @param type The type of the action.
    * @param uri The uri being downloaded or removed.
    * @param isRemoveAction Whether this is a remove action. If false, this is a download action.
-   * @param keys Keys of tracks to be downloaded. If empty, all tracks will be downloaded. Empty if
-   *     this action is a remove action.
+   * @param keys Keys of streams to be downloaded. If empty, all streams will be downloaded. Empty
+   *     if this action is a remove action.
    * @param customCacheKey A custom key for cache indexing, or null.
    * @param data Custom data for this action. Null if this action is a remove action.
    */
@@ -140,6 +142,7 @@ public final class DownloadAction {
       List<StreamKey> keys,
       @Nullable String customCacheKey,
       @Nullable byte[] data) {
+    this.id = customCacheKey != null ? customCacheKey : uri.toString();
     this.type = type;
     this.uri = uri;
     this.isRemoveAction = isRemoveAction;
@@ -171,12 +174,10 @@ public final class DownloadAction {
 
   /** Returns whether this is an action for the same media as the {@code other}. */
   public boolean isSameMedia(DownloadAction other) {
-    return customCacheKey == null
-        ? other.customCacheKey == null && uri.equals(other.uri)
-        : customCacheKey.equals(other.customCacheKey);
+    return id.equals(other.id);
   }
 
-  /** Returns keys of tracks to be downloaded. */
+  /** Returns keys of streams to be downloaded. */
   public List<StreamKey> getKeys() {
     return keys;
   }
@@ -187,7 +188,8 @@ public final class DownloadAction {
       return false;
     }
     DownloadAction that = (DownloadAction) o;
-    return type.equals(that.type)
+    return id.equals(that.id)
+        && type.equals(that.type)
         && uri.equals(that.uri)
         && isRemoveAction == that.isRemoveAction
         && keys.equals(that.keys)
@@ -198,6 +200,7 @@ public final class DownloadAction {
   @Override
   public final int hashCode() {
     int result = type.hashCode();
+    result = 31 * result + id.hashCode();
     result = 31 * result + uri.hashCode();
     result = 31 * result + (isRemoveAction ? 1 : 0);
     result = 31 * result + keys.hashCode();

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadActionUtil.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.offline;
+
+import com.google.android.exoplayer2.util.Assertions;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.HashSet;
+
+/** {@link DownloadAction} related utility methods. */
+public class DownloadActionUtil {
+
+  private DownloadActionUtil() {}
+
+  /**
+   * Merge {@link DownloadAction}s in {@code actionQueue} to minimum number of actions.
+   *
+   * <p>All actions must have the same type and must be for the same media.
+   *
+   * @param actionQueue Queue of actions. Must not be empty.
+   * @return The first action in the queue.
+   */
+  public static DownloadAction mergeActions(ArrayDeque<DownloadAction> actionQueue) {
+    DownloadAction removeAction = null;
+    DownloadAction downloadAction = null;
+    HashSet<StreamKey> keys = new HashSet<>();
+    boolean downloadAllTracks = false;
+    DownloadAction firstAction = Assertions.checkNotNull(actionQueue.peek());
+
+    while (!actionQueue.isEmpty()) {
+      DownloadAction action = actionQueue.remove();
+      Assertions.checkState(action.type.equals(firstAction.type));
+      Assertions.checkState(action.isSameMedia(firstAction));
+      if (action.isRemoveAction) {
+        removeAction = action;
+        downloadAction = null;
+        keys.clear();
+        downloadAllTracks = false;
+      } else {
+        if (!downloadAllTracks) {
+          if (action.keys.isEmpty()) {
+            downloadAllTracks = true;
+            keys.clear();
+          } else {
+            keys.addAll(action.keys);
+          }
+        }
+        downloadAction = action;
+      }
+    }
+
+    if (removeAction != null) {
+      actionQueue.add(removeAction);
+    }
+    if (downloadAction != null) {
+      actionQueue.add(
+          DownloadAction.createDownloadAction(
+              downloadAction.type,
+              downloadAction.uri,
+              new ArrayList<>(keys),
+              downloadAction.customCacheKey,
+              downloadAction.data));
+    }
+    return Assertions.checkNotNull(actionQueue.peek());
+  }
+}

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadHelper.java

@@ -19,18 +19,66 @@ import android.net.Uri;
 import android.os.Handler;
 import android.os.Looper;
 import android.support.annotation.Nullable;
+import android.util.SparseIntArray;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.RendererCapabilities;
+import com.google.android.exoplayer2.RenderersFactory;
+import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.drm.DrmSessionManager;
+import com.google.android.exoplayer2.drm.FrameworkMediaCrypto;
+import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
+import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
+import com.google.android.exoplayer2.trackselection.BaseTrackSelection;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector.Parameters;
+import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
+import com.google.android.exoplayer2.trackselection.TrackSelection;
+import com.google.android.exoplayer2.trackselection.TrackSelectorResult;
+import com.google.android.exoplayer2.upstream.BandwidthMeter;
+import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
+import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * A helper for initializing and removing downloads.
  *
+ * <p>The helper extracts track information from the media, selects tracks for downloading, and
+ * creates {@link DownloadAction download actions} based on the selected tracks.
+ *
+ * <p>A typical usage of DownloadHelper follows these steps:
+ *
+ * <ol>
+ *   <li>Construct the download helper with information about the {@link RenderersFactory renderers}
+ *       and {@link DefaultTrackSelector.Parameters parameters} for track selection.
+ *   <li>Prepare the helper using {@link #prepare(Callback)} and wait for the callback.
+ *   <li>Optional: Inspect the selected tracks using {@link #getMappedTrackInfo(int)} and {@link
+ *       #getTrackSelections(int, int)}, and make adjustments using {@link
+ *       #clearTrackSelections(int)}, {@link #replaceTrackSelections(int, Parameters)} and {@link
+ *       #addTrackSelection(int, Parameters)}.
+ *   <li>Create download actions for the selected track using {@link #getDownloadAction(byte[])}.
+ * </ol>
+ *
  * @param <T> The manifest type.
  */
 public abstract class DownloadHelper<T> {
 
+  /**
+   * The default parameters used for track selection for downloading. This default selects the
+   * highest bitrate audio and video tracks which are supported by the renderers.
+   */
+  public static final DefaultTrackSelector.Parameters DEFAULT_TRACK_SELECTOR_PARAMETERS =
+      new DefaultTrackSelector.ParametersBuilder().setForceHighestSupportedBitrate(true).build();
+
   /** A callback to be notified when the {@link DownloadHelper} is prepared. */
   public interface Callback {
 
@@ -39,7 +87,7 @@ public abstract class DownloadHelper<T> {
      *
      * @param helper The reporting {@link DownloadHelper}.
      */
-    void onPrepared(DownloadHelper helper);
+    void onPrepared(DownloadHelper<?> helper);
 
     /**
      * Called when preparation fails.
@@ -47,27 +95,51 @@ public abstract class DownloadHelper<T> {
      * @param helper The reporting {@link DownloadHelper}.
      * @param e The error.
      */
-    void onPrepareError(DownloadHelper helper, IOException e);
+    void onPrepareError(DownloadHelper<?> helper, IOException e);
   }
 
   private final String downloadType;
   private final Uri uri;
   @Nullable private final String cacheKey;
+  private final DefaultTrackSelector trackSelector;
+  private final RendererCapabilities[] rendererCapabilities;
+  private final SparseIntArray scratchSet;
 
+  private int currentTrackSelectionPeriodIndex;
   @Nullable private T manifest;
-  @Nullable private TrackGroupArray[] trackGroupArrays;
+  private TrackGroupArray @MonotonicNonNull [] trackGroupArrays;
+  private MappedTrackInfo @MonotonicNonNull [] mappedTrackInfos;
+  private List<TrackSelection> @MonotonicNonNull [][] trackSelectionsByPeriodAndRenderer;
+  private List<TrackSelection> @MonotonicNonNull [][] immutableTrackSelectionsByPeriodAndRenderer;
 
   /**
-   * Create download helper.
+   * Creates download helper.
    *
    * @param downloadType A download type. This value will be used as {@link DownloadAction#type}.
    * @param uri A {@link Uri}.
    * @param cacheKey An optional cache key.
+   * @param trackSelectorParameters {@link DefaultTrackSelector.Parameters} for selecting tracks for
+   *     downloading.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   * @param drmSessionManager An optional {@link DrmSessionManager} used by the renderers created by
+   *     {@code renderersFactory}.
    */
-  public DownloadHelper(String downloadType, Uri uri, @Nullable String cacheKey) {
+  public DownloadHelper(
+      String downloadType,
+      Uri uri,
+      @Nullable String cacheKey,
+      DefaultTrackSelector.Parameters trackSelectorParameters,
+      RenderersFactory renderersFactory,
+      @Nullable DrmSessionManager<FrameworkMediaCrypto> drmSessionManager) {
     this.downloadType = downloadType;
     this.uri = uri;
     this.cacheKey = cacheKey;
+    this.trackSelector = new DefaultTrackSelector(new DownloadTrackSelection.Factory());
+    this.rendererCapabilities = Util.getRendererCapabilities(renderersFactory, drmSessionManager);
+    this.scratchSet = new SparseIntArray();
+    trackSelector.setParameters(trackSelectorParameters);
+    trackSelector.init(/* listener= */ () -> {}, new DummyBandwidthMeter());
   }
 
   /**
@@ -77,21 +149,28 @@ public abstract class DownloadHelper<T> {
    *     will be invoked on the calling thread unless that thread does not have an associated {@link
    *     Looper}, in which case it will be called on the application's main thread.
    */
-  public final void prepare(final Callback callback) {
-    final Handler handler =
+  public final void prepare(Callback callback) {
+    Handler handler =
         new Handler(Looper.myLooper() != null ? Looper.myLooper() : Looper.getMainLooper());
-    new Thread() {
-      @Override
-      public void run() {
-        try {
-          manifest = loadManifest(uri);
-          trackGroupArrays = getTrackGroupArrays(manifest);
-          handler.post(() -> callback.onPrepared(DownloadHelper.this));
-        } catch (final IOException e) {
-          handler.post(() -> callback.onPrepareError(DownloadHelper.this, e));
-        }
-      }
-    }.start();
+    new Thread(
+            () -> {
+              try {
+                manifest = loadManifest(uri);
+                trackGroupArrays = getTrackGroupArrays(manifest);
+                initializeTrackSelectionLists(trackGroupArrays.length, rendererCapabilities.length);
+                mappedTrackInfos = new MappedTrackInfo[trackGroupArrays.length];
+                for (int i = 0; i < trackGroupArrays.length; i++) {
+                  TrackSelectorResult trackSelectorResult = runTrackSelection(/* periodIndex= */ i);
+                  trackSelector.onSelectionActivated(trackSelectorResult.info);
+                  mappedTrackInfos[i] =
+                      Assertions.checkNotNull(trackSelector.getCurrentMappedTrackInfo());
+                }
+                handler.post(() -> callback.onPrepared(DownloadHelper.this));
+              } catch (final IOException e) {
+                handler.post(() -> callback.onPrepareError(DownloadHelper.this, e));
+              }
+            })
+        .start();
   }
 
   /** Returns the manifest. Must not be called until after preparation completes. */
@@ -113,6 +192,8 @@ public abstract class DownloadHelper<T> {
    * Returns the track groups for the given period. Must not be called until after preparation
    * completes.
    *
+   * <p>Use {@link #getMappedTrackInfo(int)} to get the track groups mapped to renderers.
+   *
    * @param periodIndex The period index.
    * @return The track groups for the period. May be {@link TrackGroupArray#EMPTY} for single stream
    *     content.
@@ -123,16 +204,103 @@ public abstract class DownloadHelper<T> {
   }
 
   /**
-   * Builds a {@link DownloadAction} for downloading the specified tracks. Must not be called until
+   * Returns the mapped track info for the given period. Must not be called until after preparation
+   * completes.
+   *
+   * @param periodIndex The period index.
+   * @return The {@link MappedTrackInfo} for the period.
+   */
+  public final MappedTrackInfo getMappedTrackInfo(int periodIndex) {
+    Assertions.checkNotNull(mappedTrackInfos);
+    return mappedTrackInfos[periodIndex];
+  }
+
+  /**
+   * Returns all {@link TrackSelection track selections} for a period and renderer. Must not be
+   * called until after preparation completes.
+   *
+   * @param periodIndex The period index.
+   * @param rendererIndex The renderer index.
+   * @return A list of selected {@link TrackSelection track selections}.
+   */
+  public final List<TrackSelection> getTrackSelections(int periodIndex, int rendererIndex) {
+    Assertions.checkNotNull(immutableTrackSelectionsByPeriodAndRenderer);
+    return immutableTrackSelectionsByPeriodAndRenderer[periodIndex][rendererIndex];
+  }
+
+  /**
+   * Clears the selection of tracks for a period. Must not be called until after preparation
+   * completes.
+   *
+   * @param periodIndex The period index for which track selections are cleared.
+   */
+  public final void clearTrackSelections(int periodIndex) {
+    Assertions.checkNotNull(trackSelectionsByPeriodAndRenderer);
+    for (int i = 0; i < rendererCapabilities.length; i++) {
+      trackSelectionsByPeriodAndRenderer[periodIndex][i].clear();
+    }
+  }
+
+  /**
+   * Replaces a selection of tracks to be downloaded. Must not be called until after preparation
+   * completes.
+   *
+   * @param periodIndex The period index for which the track selection is replaced.
+   * @param trackSelectorParameters The {@link DefaultTrackSelector.Parameters} to obtain the new
+   *     selection of tracks.
+   */
+  public final void replaceTrackSelections(
+      int periodIndex, DefaultTrackSelector.Parameters trackSelectorParameters) {
+    clearTrackSelections(periodIndex);
+    addTrackSelection(periodIndex, trackSelectorParameters);
+  }
+
+  /**
+   * Adds a selection of tracks to be downloaded. Must not be called until after preparation
+   * completes.
+   *
+   * @param periodIndex The period index this track selection is added for.
+   * @param trackSelectorParameters The {@link DefaultTrackSelector.Parameters} to obtain the new
+   *     selection of tracks.
+   */
+  public final void addTrackSelection(
+      int periodIndex, DefaultTrackSelector.Parameters trackSelectorParameters) {
+    Assertions.checkNotNull(trackGroupArrays);
+    Assertions.checkNotNull(trackSelectionsByPeriodAndRenderer);
+    trackSelector.setParameters(trackSelectorParameters);
+    runTrackSelection(periodIndex);
+  }
+
+  /**
+   * Builds a {@link DownloadAction} for downloading the selected tracks. Must not be called until
    * after preparation completes.
    *
    * @param data Application provided data to store in {@link DownloadAction#data}.
-   * @param trackKeys The selected tracks. If empty, all streams will be downloaded.
    * @return The built {@link DownloadAction}.
    */
-  public final DownloadAction getDownloadAction(@Nullable byte[] data, List<TrackKey> trackKeys) {
-    return DownloadAction.createDownloadAction(
-        downloadType, uri, toStreamKeys(trackKeys), cacheKey, data);
+  public final DownloadAction getDownloadAction(@Nullable byte[] data) {
+    Assertions.checkNotNull(trackSelectionsByPeriodAndRenderer);
+    Assertions.checkNotNull(trackGroupArrays);
+    List<StreamKey> streamKeys = new ArrayList<>();
+    int periodCount = trackSelectionsByPeriodAndRenderer.length;
+    for (int periodIndex = 0; periodIndex < periodCount; periodIndex++) {
+      int rendererCount = trackSelectionsByPeriodAndRenderer[periodIndex].length;
+      for (int rendererIndex = 0; rendererIndex < rendererCount; rendererIndex++) {
+        List<TrackSelection> trackSelectionList =
+            trackSelectionsByPeriodAndRenderer[periodIndex][rendererIndex];
+        for (int selectionIndex = 0; selectionIndex < trackSelectionList.size(); selectionIndex++) {
+          TrackSelection trackSelection = trackSelectionList.get(selectionIndex);
+          int trackGroupIndex =
+              trackGroupArrays[periodIndex].indexOf(trackSelection.getTrackGroup());
+          int trackCount = trackSelection.length();
+          for (int trackListIndex = 0; trackListIndex < trackCount; trackListIndex++) {
+            int trackIndex = trackSelection.getIndexInTrackGroup(trackListIndex);
+            streamKeys.add(toStreamKey(periodIndex, trackGroupIndex, trackIndex));
+          }
+        }
+      }
+    }
+    return DownloadAction.createDownloadAction(downloadType, uri, streamKeys, cacheKey, data);
   }
 
   /**
@@ -161,10 +329,151 @@ public abstract class DownloadHelper<T> {
   protected abstract TrackGroupArray[] getTrackGroupArrays(T manifest);
 
   /**
-   * Converts a list of {@link TrackKey track keys} to {@link StreamKey stream keys}.
+   * Converts a track of a track group of a period to the corresponding {@link StreamKey}.
    *
-   * @param trackKeys A list of track keys.
-   * @return A corresponding list of stream keys.
+   * @param periodIndex The index of the containing period.
+   * @param trackGroupIndex The index of the containing track group within the period.
+   * @param trackIndexInTrackGroup The index of the track within the track group.
+   * @return The corresponding {@link StreamKey}.
    */
-  protected abstract List<StreamKey> toStreamKeys(List<TrackKey> trackKeys);
+  protected abstract StreamKey toStreamKey(
+      int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup);
+
+  @SuppressWarnings("unchecked")
+  @EnsuresNonNull("trackSelectionsByPeriodAndRenderer")
+  private void initializeTrackSelectionLists(int periodCount, int rendererCount) {
+    trackSelectionsByPeriodAndRenderer =
+        (List<TrackSelection>[][]) new List<?>[periodCount][rendererCount];
+    immutableTrackSelectionsByPeriodAndRenderer =
+        (List<TrackSelection>[][]) new List<?>[periodCount][rendererCount];
+    for (int i = 0; i < periodCount; i++) {
+      for (int j = 0; j < rendererCount; j++) {
+        trackSelectionsByPeriodAndRenderer[i][j] = new ArrayList<>();
+        immutableTrackSelectionsByPeriodAndRenderer[i][j] =
+            Collections.unmodifiableList(trackSelectionsByPeriodAndRenderer[i][j]);
+      }
+    }
+  }
+
+  /**
+   * Runs the track selection for a given period index with the current parameters. The selected
+   * tracks will be added to {@link #trackSelectionsByPeriodAndRenderer}.
+   */
+  // Intentional reference comparison of track group instances.
+  @SuppressWarnings("ReferenceEquality")
+  @RequiresNonNull({"trackGroupArrays", "trackSelectionsByPeriodAndRenderer"})
+  private TrackSelectorResult runTrackSelection(int periodIndex) {
+    // TODO: Use actual timeline and media period id.
+    MediaPeriodId dummyMediaPeriodId = new MediaPeriodId(new Object());
+    Timeline dummyTimeline = Timeline.EMPTY;
+    currentTrackSelectionPeriodIndex = periodIndex;
+    try {
+      TrackSelectorResult trackSelectorResult =
+          trackSelector.selectTracks(
+              rendererCapabilities,
+              trackGroupArrays[periodIndex],
+              dummyMediaPeriodId,
+              dummyTimeline);
+      for (int i = 0; i < trackSelectorResult.length; i++) {
+        TrackSelection newSelection = trackSelectorResult.selections.get(i);
+        if (newSelection == null) {
+          continue;
+        }
+        List<TrackSelection> existingSelectionList =
+            trackSelectionsByPeriodAndRenderer[currentTrackSelectionPeriodIndex][i];
+        boolean mergedWithExistingSelection = false;
+        for (int j = 0; j < existingSelectionList.size(); j++) {
+          TrackSelection existingSelection = existingSelectionList.get(j);
+          if (existingSelection.getTrackGroup() == newSelection.getTrackGroup()) {
+            // Merge with existing selection.
+            scratchSet.clear();
+            for (int k = 0; k < existingSelection.length(); k++) {
+              scratchSet.put(existingSelection.getIndexInTrackGroup(k), 0);
+            }
+            for (int k = 0; k < newSelection.length(); k++) {
+              scratchSet.put(newSelection.getIndexInTrackGroup(k), 0);
+            }
+            int[] mergedTracks = new int[scratchSet.size()];
+            for (int k = 0; k < scratchSet.size(); k++) {
+              mergedTracks[k] = scratchSet.keyAt(k);
+            }
+            existingSelectionList.set(
+                j, new DownloadTrackSelection(existingSelection.getTrackGroup(), mergedTracks));
+            mergedWithExistingSelection = true;
+            break;
+          }
+        }
+        if (!mergedWithExistingSelection) {
+          existingSelectionList.add(newSelection);
+        }
+      }
+      return trackSelectorResult;
+    } catch (ExoPlaybackException e) {
+      // DefaultTrackSelector does not throw exceptions during track selection.
+      throw new UnsupportedOperationException(e);
+    }
+  }
+
+  private static final class DownloadTrackSelection extends BaseTrackSelection {
+
+    private static final class Factory implements TrackSelection.Factory {
+
+      @Override
+      public @NullableType TrackSelection[] createTrackSelections(
+          @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
+        @NullableType TrackSelection[] selections = new TrackSelection[definitions.length];
+        for (int i = 0; i < definitions.length; i++) {
+          selections[i] =
+              definitions[i] == null
+                  ? null
+                  : new DownloadTrackSelection(definitions[i].group, definitions[i].tracks);
+        }
+        return selections;
+      }
+    }
+
+    public DownloadTrackSelection(TrackGroup trackGroup, int[] tracks) {
+      super(trackGroup, tracks);
+    }
+
+    @Override
+    public int getSelectedIndex() {
+      return 0;
+    }
+
+    @Override
+    public int getSelectionReason() {
+      return C.SELECTION_REASON_UNKNOWN;
+    }
+
+    @Nullable
+    @Override
+    public Object getSelectionData() {
+      return null;
+    }
+  }
+
+  private static final class DummyBandwidthMeter implements BandwidthMeter {
+
+    @Override
+    public long getBitrateEstimate() {
+      return 0;
+    }
+
+    @Nullable
+    @Override
+    public TransferListener getTransferListener() {
+      return null;
+    }
+
+    @Override
+    public void addEventListener(Handler eventHandler, EventListener eventListener) {
+      // Do nothing.
+    }
+
+    @Override
+    public void removeEventListener(EventListener eventListener) {
+      // Do nothing.
+    }
+  }
 }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadManager.java

@@ -15,11 +15,12 @@
  */
 package com.google.android.exoplayer2.offline;
 
-import static com.google.android.exoplayer2.offline.DownloadManager.TaskState.STATE_CANCELED;
-import static com.google.android.exoplayer2.offline.DownloadManager.TaskState.STATE_COMPLETED;
-import static com.google.android.exoplayer2.offline.DownloadManager.TaskState.STATE_FAILED;
-import static com.google.android.exoplayer2.offline.DownloadManager.TaskState.STATE_QUEUED;
-import static com.google.android.exoplayer2.offline.DownloadManager.TaskState.STATE_STARTED;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.FAILURE_REASON_NONE;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.FAILURE_REASON_UNKNOWN;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.STATE_COMPLETED;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.STATE_FAILED;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.STATE_QUEUED;
+import static com.google.android.exoplayer2.offline.DownloadManager.DownloadState.STATE_STARTED;
 
 import android.os.ConditionVariable;
 import android.os.Handler;
@@ -35,6 +36,7 @@ import java.io.IOException;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArraySet;
@@ -58,41 +60,40 @@ public final class DownloadManager {
      */
     void onInitialized(DownloadManager downloadManager);
     /**
-     * Called when the state of a task changes.
+     * Called when the state of a download changes.
      *
      * @param downloadManager The reporting instance.
-     * @param taskState The state of the task.
+     * @param downloadState The state of the download.
      */
-    void onTaskStateChanged(DownloadManager downloadManager, TaskState taskState);
+    void onDownloadStateChanged(DownloadManager downloadManager, DownloadState downloadState);
 
     /**
-     * Called when there is no active task left.
+     * Called when there is no active download left.
      *
      * @param downloadManager The reporting instance.
      */
     void onIdle(DownloadManager downloadManager);
   }
 
-  /** The default maximum number of simultaneous download tasks. */
+  /** The default maximum number of simultaneous downloads. */
   public static final int DEFAULT_MAX_SIMULTANEOUS_DOWNLOADS = 1;
-  /** The default minimum number of times a task must be retried before failing. */
+  /** The default minimum number of times a download must be retried before failing. */
   public static final int DEFAULT_MIN_RETRY_COUNT = 5;
 
   private static final String TAG = "DownloadManager";
   private static final boolean DEBUG = false;
 
-  private final int maxActiveDownloadTasks;
+  private final int maxActiveDownloads;
   private final int minRetryCount;
   private final ActionFile actionFile;
   private final DownloaderFactory downloaderFactory;
-  private final ArrayList<Task> tasks;
-  private final ArrayList<Task> activeDownloadTasks;
+  private final ArrayList<Download> downloads;
+  private final ArrayList<Download> activeDownloads;
   private final Handler handler;
   private final HandlerThread fileIOThread;
   private final Handler fileIOHandler;
   private final CopyOnWriteArraySet<Listener> listeners;
 
-  private int nextTaskId;
   private boolean initialized;
   private boolean released;
   private boolean downloadsStopped;
@@ -113,8 +114,8 @@ public final class DownloadManager {
    *
    * @param actionFile The file in which active actions are saved.
    * @param downloaderFactory A factory for creating {@link Downloader}s.
-   * @param maxSimultaneousDownloads The maximum number of simultaneous download tasks.
-   * @param minRetryCount The minimum number of times a task must be retried before failing.
+   * @param maxSimultaneousDownloads The maximum number of simultaneous downloads.
+   * @param minRetryCount The minimum number of times a download must be retried before failing.
    */
   public DownloadManager(
       File actionFile,
@@ -123,12 +124,12 @@ public final class DownloadManager {
       int minRetryCount) {
     this.actionFile = new ActionFile(actionFile);
     this.downloaderFactory = downloaderFactory;
-    this.maxActiveDownloadTasks = maxSimultaneousDownloads;
+    this.maxActiveDownloads = maxSimultaneousDownloads;
     this.minRetryCount = minRetryCount;
     this.downloadsStopped = true;
 
-    tasks = new ArrayList<>();
-    activeDownloadTasks = new ArrayList<>();
+    downloads = new ArrayList<>();
+    activeDownloads = new ArrayList<>();
 
     Looper looper = Looper.myLooper();
     if (looper == null) {
@@ -164,85 +165,78 @@ public final class DownloadManager {
     listeners.remove(listener);
   }
 
-  /** Starts the download tasks. */
+  /** Starts the downloads. */
   public void startDownloads() {
     Assertions.checkState(!released);
     if (downloadsStopped) {
       downloadsStopped = false;
-      maybeStartTasks();
+      maybeStartDownloads();
       logd("Downloads are started");
     }
   }
 
-  /** Stops all of the download tasks. Call {@link #startDownloads()} to restart tasks. */
+  /** Stops all of the downloads. Call {@link #startDownloads()} to restart downloads. */
   public void stopDownloads() {
     Assertions.checkState(!released);
     if (!downloadsStopped) {
       downloadsStopped = true;
-      for (int i = 0; i < activeDownloadTasks.size(); i++) {
-        activeDownloadTasks.get(i).stop();
+      for (int i = 0; i < activeDownloads.size(); i++) {
+        activeDownloads.get(i).stop();
       }
       logd("Downloads are stopping");
     }
   }
 
   /**
-   * Handles the given action. A task is created and added to the task queue. If it's a remove
-   * action then any download tasks for the same media are immediately canceled.
+   * Handles the given action.
    *
    * @param action The action to be executed.
-   * @return The id of the newly created task.
    */
-  public int handleAction(DownloadAction action) {
+  public void handleAction(DownloadAction action) {
     Assertions.checkState(!released);
-    Task task = addTaskForAction(action);
+    Download download = getDownloadForAction(action);
     if (initialized) {
       saveActions();
-      maybeStartTasks();
-      if (task.state == STATE_QUEUED) {
-        // Task did not change out of its initial state, and so its initial state won't have been
+      maybeStartDownloads();
+      if (download.state == STATE_QUEUED) {
+        // Download did not change out of its initial state, and so its initial state won't have
+        // been
         // reported to listeners. Do so now.
-        notifyListenersTaskStateChange(task);
+        notifyListenersDownloadStateChange(download);
       }
     }
-    return task.id;
   }
 
-  /** Returns the number of tasks. */
-  public int getTaskCount() {
-    Assertions.checkState(!released);
-    return tasks.size();
-  }
-
-  /** Returns the number of download tasks. */
+  /** Returns the number of downloads. */
   public int getDownloadCount() {
-    int count = 0;
-    for (int i = 0; i < tasks.size(); i++) {
-      if (!tasks.get(i).action.isRemoveAction) {
-        count++;
-      }
-    }
-    return count;
+    Assertions.checkState(!released);
+    return downloads.size();
   }
 
-  /** Returns the state of a task, or null if no such task exists */
-  public @Nullable TaskState getTaskState(int taskId) {
+  /**
+   * Returns {@link DownloadState} for the given content id, or null if no such download exists.
+   *
+   * @param id The unique content id.
+   * @return DownloadState for the given content id, or null if no such download exists.
+   */
+  @Nullable
+  public DownloadState getDownloadState(String id) {
     Assertions.checkState(!released);
-    for (int i = 0; i < tasks.size(); i++) {
-      Task task = tasks.get(i);
-      if (task.id == taskId) {
-        return task.getTaskState();
+    for (int i = 0; i < downloads.size(); i++) {
+      Download download = downloads.get(i);
+      if (download.id.equals(id)) {
+        return download.getDownloadState();
       }
     }
     return null;
   }
 
-  /** Returns the states of all current tasks. */
-  public TaskState[] getAllTaskStates() {
+  /** Returns the states of all current downloads. */
+  public DownloadState[] getAllDownloadStates() {
     Assertions.checkState(!released);
-    TaskState[] states = new TaskState[tasks.size()];
+    DownloadState[] states = new DownloadState[downloads.size()];
     for (int i = 0; i < states.length; i++) {
-      states[i] = tasks.get(i).getTaskState();
+      states[i] = downloads.get(i).getDownloadState();
     }
     return states;
   }
@@ -253,14 +247,14 @@ public final class DownloadManager {
     return initialized;
   }
 
-  /** Returns whether there are no active tasks. */
+  /** Returns whether there are no active downloads. */
   public boolean isIdle() {
     Assertions.checkState(!released);
     if (!initialized) {
       return false;
     }
-    for (int i = 0; i < tasks.size(); i++) {
-      if (tasks.get(i).isStarted()) {
+    for (int i = 0; i < downloads.size(); i++) {
+      if (downloads.get(i).isStarted()) {
         return false;
       }
     }
@@ -268,16 +262,17 @@ public final class DownloadManager {
   }
 
   /**
-   * Stops all of the tasks and releases resources. If the action file isn't up to date, waits for
-   * the changes to be written. The manager must not be accessed after this method has been called.
+   * Stops all of the downloads and releases resources. If the action file isn't up to date, waits
+   * for the changes to be written. The manager must not be accessed after this method has been
+   * called.
    */
   public void release() {
     if (released) {
       return;
     }
     released = true;
-    for (int i = 0; i < tasks.size(); i++) {
-      tasks.get(i).stop();
+    for (int i = 0; i < downloads.size(); i++) {
+      downloads.get(i).stop();
     }
     final ConditionVariable fileIOFinishedCondition = new ConditionVariable();
     fileIOHandler.post(fileIOFinishedCondition::open);
@@ -286,66 +281,46 @@ public final class DownloadManager {
     logd("Released");
   }
 
-  private Task addTaskForAction(DownloadAction action) {
-    Task task = new Task(nextTaskId++, this, downloaderFactory, action, minRetryCount);
-    tasks.add(task);
-    logd("Task is added", task);
-    return task;
+  private Download getDownloadForAction(DownloadAction action) {
+    for (int i = 0; i < downloads.size(); i++) {
+      Download download = downloads.get(i);
+      if (download.action.isSameMedia(action)) {
+        download.addAction(action);
+        logd("Action is added to existing download", download);
+        return download;
+      }
+    }
+    Download download = new Download(this, downloaderFactory, action, minRetryCount);
+    downloads.add(download);
+    logd("Download is added", download);
+    return download;
   }
 
   /**
-   * Iterates through the task queue and starts any task if all of the following are true:
+   * Iterates through the download queue and starts any download if all of the following are true:
    *
    * <ul>
    *   <li>It hasn't started yet.
-   *   <li>There are no preceding conflicting tasks.
-   *   <li>If it's a download task then there are no preceding download tasks on hold and the
-   *       maximum number of active downloads hasn't been reached.
+   *   <li>The maximum number of active downloads hasn't been reached.
    * </ul>
-   *
-   * If the task is a remove action then preceding conflicting tasks are canceled.
    */
-  private void maybeStartTasks() {
+  private void maybeStartDownloads() {
     if (!initialized || released) {
       return;
     }
 
-    boolean skipDownloadActions = downloadsStopped
-        || activeDownloadTasks.size() == maxActiveDownloadTasks;
-    for (int i = 0; i < tasks.size(); i++) {
-      Task task = tasks.get(i);
-      if (!task.canStart()) {
+    boolean skipDownloads = downloadsStopped || activeDownloads.size() == maxActiveDownloads;
+    for (int i = 0; i < downloads.size(); i++) {
+      Download download = downloads.get(i);
+      if (!download.canStart()) {
         continue;
       }
-
-      DownloadAction action = task.action;
-      boolean isRemoveAction = action.isRemoveAction;
-      if (!isRemoveAction && skipDownloadActions) {
-        continue;
-      }
-
-      boolean canStartTask = true;
-      for (int j = 0; j < i; j++) {
-        Task otherTask = tasks.get(j);
-        if (otherTask.action.isSameMedia(action)) {
-          if (isRemoveAction) {
-            canStartTask = false;
-            logd(task + " clashes with " + otherTask);
-            otherTask.cancel();
-            // Continue loop to cancel any other preceding clashing tasks.
-          } else if (otherTask.action.isRemoveAction) {
-            canStartTask = false;
-            skipDownloadActions = true;
-            break;
-          }
-        }
-      }
-
-      if (canStartTask) {
-        task.start();
+      boolean isRemoveAction = download.action.isRemoveAction;
+      if (isRemoveAction || !skipDownloads) {
+        download.start();
         if (!isRemoveAction) {
-          activeDownloadTasks.add(task);
-          skipDownloadActions = activeDownloadTasks.size() == maxActiveDownloadTasks;
+          activeDownloads.add(download);
+          skipDownloads = activeDownloads.size() == maxActiveDownloads;
         }
       }
     }
@@ -361,30 +336,30 @@ public final class DownloadManager {
     }
   }
 
-  private void onTaskStateChange(Task task) {
+  private void onDownloadStateChange(Download download) {
     if (released) {
       return;
     }
-    boolean stopped = !task.isStarted();
+    boolean stopped = !download.isStarted();
     if (stopped) {
-      activeDownloadTasks.remove(task);
+      activeDownloads.remove(download);
     }
-    notifyListenersTaskStateChange(task);
-    if (task.isFinished()) {
-      tasks.remove(task);
+    notifyListenersDownloadStateChange(download);
+    if (download.isFinished()) {
+      downloads.remove(download);
       saveActions();
     }
     if (stopped) {
-      maybeStartTasks();
+      maybeStartDownloads();
       maybeNotifyListenersIdle();
     }
   }
 
-  private void notifyListenersTaskStateChange(Task task) {
-    logd("Task state is changed", task);
-    TaskState taskState = task.getTaskState();
+  private void notifyListenersDownloadStateChange(Download download) {
+    logd("Download state is changed", download);
+    DownloadState downloadState = download.getDownloadState();
     for (Listener listener : listeners) {
-      listener.onTaskStateChanged(this, taskState);
+      listener.onDownloadStateChanged(this, downloadState);
     }
   }
 
@@ -405,27 +380,27 @@ public final class DownloadManager {
                 if (released) {
                   return;
                 }
-                List<Task> pendingTasks = new ArrayList<>(tasks);
-                tasks.clear();
+                List<Download> pendingDownloads = new ArrayList<>(downloads);
+                downloads.clear();
                 for (DownloadAction action : actions) {
-                  addTaskForAction(action);
+                  getDownloadForAction(action);
                 }
-                logd("Tasks are created.");
+                logd("Downloads are created.");
                 initialized = true;
                 for (Listener listener : listeners) {
                   listener.onInitialized(DownloadManager.this);
                 }
-                if (!pendingTasks.isEmpty()) {
-                  tasks.addAll(pendingTasks);
+                if (!pendingDownloads.isEmpty()) {
+                  downloads.addAll(pendingDownloads);
                   saveActions();
                 }
-                maybeStartTasks();
-                for (int i = 0; i < tasks.size(); i++) {
-                  Task task = tasks.get(i);
-                  if (task.state == STATE_QUEUED) {
-                    // Task did not change out of its initial state, and so its initial state
+                maybeStartDownloads();
+                for (int i = 0; i < downloads.size(); i++) {
+                  Download download = downloads.get(i);
+                  if (download.state == STATE_QUEUED) {
+                    // Download did not change out of its initial state, and so its initial state
                     // won't have been reported to listeners. Do so now.
-                    notifyListenersTaskStateChange(task);
+                    notifyListenersDownloadStateChange(download);
                   }
                 }
               });
@@ -436,14 +411,15 @@ public final class DownloadManager {
     if (released) {
       return;
     }
-    final DownloadAction[] actions = new DownloadAction[tasks.size()];
-    for (int i = 0; i < tasks.size(); i++) {
-      actions[i] = tasks.get(i).action;
+    ArrayList<DownloadAction> actions = new ArrayList<>(downloads.size());
+    for (int i = 0; i < downloads.size(); i++) {
+      actions.addAll(downloads.get(i).actionQueue);
     }
+    final DownloadAction[] actionsArray = actions.toArray(new DownloadAction[0]);
     fileIOHandler.post(
         () -> {
           try {
-            actionFile.store(actions);
+            actionFile.store(actionsArray);
             logd("Actions persisted.");
           } catch (IOException e) {
             Log.e(TAG, "Persisting actions failed.", e);
@@ -457,39 +433,46 @@ public final class DownloadManager {
     }
   }
 
-  private static void logd(String message, Task task) {
-    logd(message + ": " + task);
+  private static void logd(String message, Download download) {
+    logd(message + ": " + download);
   }
 
-  /** Represents state of a task. */
-  public static final class TaskState {
+  /** Represents state of a download. */
+  public static final class DownloadState {
 
     /**
-     * Task states. One of {@link #STATE_QUEUED}, {@link #STATE_STARTED}, {@link #STATE_COMPLETED},
-     * {@link #STATE_CANCELED} or {@link #STATE_FAILED}.
+     * Download states. One of {@link #STATE_QUEUED}, {@link #STATE_STARTED}, {@link
+     * #STATE_COMPLETED} or {@link #STATE_FAILED}.
      *
      * <p>Transition diagram:
      *
      * <pre>
-     *    ┌────────┬─────→ canceled
      * queued ↔ started ┬→ completed
      *                  └→ failed
      * </pre>
      */
     @Documented
     @Retention(RetentionPolicy.SOURCE)
-    @IntDef({STATE_QUEUED, STATE_STARTED, STATE_COMPLETED, STATE_CANCELED, STATE_FAILED})
+    @IntDef({STATE_QUEUED, STATE_STARTED, STATE_COMPLETED, STATE_FAILED})
     public @interface State {}
-    /** The task is waiting to be started. */
+    /** The download is waiting to be started. */
     public static final int STATE_QUEUED = 0;
-    /** The task is currently started. */
+    /** The download is currently started. */
     public static final int STATE_STARTED = 1;
-    /** The task completed. */
+    /** The download completed. */
     public static final int STATE_COMPLETED = 2;
-    /** The task was canceled. */
-    public static final int STATE_CANCELED = 3;
-    /** The task failed. */
-    public static final int STATE_FAILED = 4;
+    /** The download failed. */
+    public static final int STATE_FAILED = 3;
+
+    /** Failure reasons. Either {@link #FAILURE_REASON_NONE} or {@link #FAILURE_REASON_UNKNOWN}. */
+    @Documented
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({FAILURE_REASON_NONE, FAILURE_REASON_UNKNOWN})
+    public @interface FailureReason {}
+    /** The download isn't failed. */
+    public static final int FAILURE_REASON_NONE = 0;
+    /** The download is failed because of unknown reason. */
+    public static final int FAILURE_REASON_UNKNOWN = 1;
 
     /** Returns the state string for the given state value. */
     public static String getStateString(@State int state) {
@@ -500,8 +483,6 @@ public final class DownloadManager {
           return "STARTED";
         case STATE_COMPLETED:
           return "COMPLETED";
-        case STATE_CANCELED:
-          return "CANCELED";
         case STATE_FAILED:
           return "FAILED";
         default:
@@ -509,97 +490,151 @@ public final class DownloadManager {
       }
     }
 
-    /** The unique task id. */
-    public final int taskId;
+    /** Returns the failure string for the given failure reason value. */
+    public static String getFailureString(@FailureReason int failureReason) {
+      switch (failureReason) {
+        case FAILURE_REASON_NONE:
+          return "NO_REASON";
+        case FAILURE_REASON_UNKNOWN:
+          return "UNKNOWN_REASON";
+        default:
+          throw new IllegalStateException();
+      }
+    }
+
+    /** The unique content id. */
+    public final String id;
     /** The action being executed. */
     public final DownloadAction action;
-    /** The state of the task. */
+    /** The state of the download. */
     public final @State int state;
-
-    /**
-     * The estimated download percentage, or {@link C#PERCENTAGE_UNSET} if no estimate is available
-     * or if this is a removal task.
-     */
+    /** The estimated download percentage, or {@link C#PERCENTAGE_UNSET} if unavailable. */
     public final float downloadPercentage;
     /** The total number of downloaded bytes. */
     public final long downloadedBytes;
+    /** The total size of the media, or {@link C#LENGTH_UNSET} if unknown. */
+    public final long totalBytes;
+    /** The first time when download entry is created. */
+    public final long startTimeMs;
+    /** The last update time. */
+    public final long updateTimeMs;
 
-    /** If {@link #state} is {@link #STATE_FAILED} then this is the cause, otherwise null. */
-    @Nullable public final Throwable error;
+    /**
+     * If {@link #state} is {@link #STATE_FAILED} then this is the cause, otherwise {@link
+     * #FAILURE_REASON_NONE}.
+     */
+    @FailureReason public final int failureReason;
 
-    private TaskState(
-        int taskId,
+    private DownloadState(
         DownloadAction action,
         @State int state,
         float downloadPercentage,
         long downloadedBytes,
-        @Nullable Throwable error) {
-      this.taskId = taskId;
+        long totalBytes,
+        @FailureReason int failureReason,
+        long startTimeMs) {
+      Assertions.checkState(
+          failureReason == FAILURE_REASON_NONE ? state != STATE_FAILED : state == STATE_FAILED);
+      this.id = action.id;
       this.action = action;
       this.state = state;
       this.downloadPercentage = downloadPercentage;
       this.downloadedBytes = downloadedBytes;
-      this.error = error;
+      this.totalBytes = totalBytes;
+      this.failureReason = failureReason;
+      this.startTimeMs = startTimeMs;
+      updateTimeMs = System.currentTimeMillis();
     }
 
   }
 
-  private static final class Task implements Runnable {
+  private static final class Download {
 
     /** Target states for the download thread. */
     @Documented
     @Retention(RetentionPolicy.SOURCE)
-    @IntDef({STATE_COMPLETED, STATE_QUEUED, STATE_CANCELED})
+    @IntDef({STATE_QUEUED, STATE_COMPLETED})
     public @interface TargetState {}
 
-    private final int id;
+    private final String id;
     private final DownloadManager downloadManager;
     private final DownloaderFactory downloaderFactory;
-    private final DownloadAction action;
     private final int minRetryCount;
-    /** The current state of the task. */
-    @TaskState.State private int state;
+    private final long startTimeMs;
+    private final ArrayDeque<DownloadAction> actionQueue;
+    private DownloadAction action;
+    /** The current state of the download. */
+    @DownloadState.State private int state;
     /**
-     * When started, this is the target state that the task will transition to when the download
+     * When started, this is the target state that the download will transition to when the download
      * thread stops.
      */
     @TargetState private volatile int targetState;
 
     @MonotonicNonNull private Downloader downloader;
-    @MonotonicNonNull private Thread thread;
-    @MonotonicNonNull private Throwable error;
+    @MonotonicNonNull private DownloadThread downloadThread;
+    @MonotonicNonNull @DownloadState.FailureReason private int failureReason;
 
-    private Task(
-        int id,
+    private Download(
         DownloadManager downloadManager,
         DownloaderFactory downloaderFactory,
         DownloadAction action,
         int minRetryCount) {
-      this.id = id;
+      this.id = action.id;
       this.downloadManager = downloadManager;
       this.downloaderFactory = downloaderFactory;
       this.action = action;
       this.minRetryCount = minRetryCount;
+      this.startTimeMs = System.currentTimeMillis();
       state = STATE_QUEUED;
       targetState = STATE_COMPLETED;
+      actionQueue = new ArrayDeque<>();
+      actionQueue.add(action);
     }
 
-    public TaskState getTaskState() {
+    public void addAction(DownloadAction newAction) {
+      Assertions.checkState(action.type.equals(newAction.type));
+      actionQueue.add(newAction);
+      DownloadAction updatedAction = DownloadActionUtil.mergeActions(actionQueue);
+      if (action.equals(updatedAction)) {
+        return;
+      }
+      if (state == STATE_STARTED) {
+        if (targetState == STATE_COMPLETED) {
+          stopDownloadThread();
+        }
+      } else {
+        Assertions.checkState(state == STATE_QUEUED);
+        action = updatedAction;
+        downloadManager.onDownloadStateChange(this);
+      }
+    }
+
+    public DownloadState getDownloadState() {
       float downloadPercentage = C.PERCENTAGE_UNSET;
       long downloadedBytes = 0;
+      long totalBytes = C.LENGTH_UNSET;
       if (downloader != null) {
         downloadPercentage = downloader.getDownloadPercentage();
         downloadedBytes = downloader.getDownloadedBytes();
+        totalBytes = downloader.getTotalBytes();
       }
-      return new TaskState(id, action, state, downloadPercentage, downloadedBytes, error);
+      return new DownloadState(
+          action,
+          state,
+          downloadPercentage,
+          downloadedBytes,
+          totalBytes,
+          failureReason,
+          startTimeMs);
     }
 
-    /** Returns whether the task is finished. */
+    /** Returns whether the download is finished. */
     public boolean isFinished() {
-      return state == STATE_FAILED || state == STATE_COMPLETED || state == STATE_CANCELED;
+      return state == STATE_FAILED || state == STATE_COMPLETED;
     }
 
-    /** Returns whether the task is started. */
+    /** Returns whether the download is started. */
     public boolean isStarted() {
       return state == STATE_STARTED;
     }
@@ -610,9 +645,9 @@ public final class DownloadManager {
           + ' '
           + (action.isRemoveAction ? "remove" : "download")
           + ' '
-          + TaskState.getStateString(state)
+          + DownloadState.getStateString(state)
           + ' '
-          + TaskState.getStateString(targetState);
+          + DownloadState.getStateString(targetState);
     }
 
     public boolean canStart() {
@@ -622,77 +657,108 @@ public final class DownloadManager {
     public void start() {
       if (state == STATE_QUEUED) {
         state = STATE_STARTED;
+        action = actionQueue.peek();
         targetState = STATE_COMPLETED;
-        downloadManager.onTaskStateChange(this);
         downloader = downloaderFactory.createDownloader(action);
-        thread = new Thread(this);
-        thread.start();
-      }
-    }
-
-    public void cancel() {
-      if (state == STATE_STARTED) {
-        stopDownloadThread(STATE_CANCELED);
-      } else if (state == STATE_QUEUED) {
-        state = STATE_CANCELED;
-        downloadManager.handler.post(() -> downloadManager.onTaskStateChange(this));
+        downloadThread =
+            new DownloadThread(
+                this, downloader, action.isRemoveAction, minRetryCount, downloadManager.handler);
+        downloadManager.onDownloadStateChange(this);
       }
     }
 
     public void stop() {
-      if (state == STATE_STARTED && targetState == STATE_COMPLETED) {
-        stopDownloadThread(STATE_QUEUED);
+      if (state == STATE_STARTED) {
+        stopDownloadThread();
       }
     }
 
     // Internal methods running on the main thread.
 
-    private void stopDownloadThread(@TargetState int targetState) {
-      this.targetState = targetState;
-      Assertions.checkNotNull(downloader).cancel();
-      Assertions.checkNotNull(thread).interrupt();
+    private void stopDownloadThread() {
+      this.targetState = DownloadState.STATE_QUEUED;
+      Assertions.checkNotNull(downloadThread).cancel();
     }
 
     private void onDownloadThreadStopped(@Nullable Throwable finalError) {
-      @TaskState.State int finalState = targetState;
-      if (targetState == STATE_COMPLETED && finalError != null) {
-        finalState = STATE_FAILED;
-      } else {
-        finalError = null;
+      state = targetState;
+      failureReason = FAILURE_REASON_NONE;
+      if (targetState == STATE_COMPLETED) {
+        if (finalError != null) {
+          state = STATE_FAILED;
+          failureReason = FAILURE_REASON_UNKNOWN;
+        } else {
+          actionQueue.remove();
+          if (!actionQueue.isEmpty()) {
+            // Don't continue running. Wait to be restarted by maybeStartDownloads().
+            state = STATE_QUEUED;
+            action = actionQueue.peek();
+          }
+        }
       }
-      state = finalState;
-      error = finalError;
-      downloadManager.onTaskStateChange(this);
+      downloadManager.onDownloadStateChange(this);
+    }
+  }
+
+  private static class DownloadThread implements Runnable {
+
+    private final Download download;
+    private final Downloader downloader;
+    private final boolean remove;
+    private final int minRetryCount;
+    private final Handler callbackHandler;
+    private final Thread thread;
+    private volatile boolean isCanceled;
+
+    private DownloadThread(
+        Download download,
+        Downloader downloader,
+        boolean remove,
+        int minRetryCount,
+        Handler callbackHandler) {
+      this.download = download;
+      this.downloader = downloader;
+      this.remove = remove;
+      this.minRetryCount = minRetryCount;
+      this.callbackHandler = callbackHandler;
+      thread = new Thread(this);
+      thread.start();
+    }
+
+    public void cancel() {
+      isCanceled = true;
+      downloader.cancel();
+      thread.interrupt();
     }
 
     // Methods running on download thread.
 
     @Override
     public void run() {
-      logd("Task is started", this);
+      logd("Download is started", download);
       Throwable error = null;
       try {
-        if (action.isRemoveAction) {
+        if (remove) {
           downloader.remove();
         } else {
           int errorCount = 0;
           long errorPosition = C.LENGTH_UNSET;
-          while (targetState == STATE_COMPLETED) {
+          while (!isCanceled) {
             try {
               downloader.download();
               break;
             } catch (IOException e) {
-              if (targetState == STATE_COMPLETED) {
+              if (!isCanceled) {
                 long downloadedBytes = downloader.getDownloadedBytes();
                 if (downloadedBytes != errorPosition) {
-                  logd("Reset error count. downloadedBytes = " + downloadedBytes, this);
+                  logd("Reset error count. downloadedBytes = " + downloadedBytes, download);
                   errorPosition = downloadedBytes;
                   errorCount = 0;
                 }
                 if (++errorCount > minRetryCount) {
                   throw e;
                 }
-                logd("Download error. Retry " + errorCount, this);
+                logd("Download error. Retry " + errorCount, download);
                 Thread.sleep(getRetryDelayMillis(errorCount));
               }
             }
@@ -702,7 +768,7 @@ public final class DownloadManager {
         error = e;
       }
       final Throwable finalError = error;
-      downloadManager.handler.post(() -> onDownloadThreadStopped(finalError));
+      callbackHandler.post(() -> download.onDownloadThreadStopped(isCanceled ? null : finalError));
     }
 
     private int getRetryDelayMillis(int errorCount) {

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadService.java

@@ -24,7 +24,7 @@ import android.os.IBinder;
 import android.os.Looper;
 import android.support.annotation.Nullable;
 import android.support.annotation.StringRes;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 import com.google.android.exoplayer2.scheduler.Requirements;
 import com.google.android.exoplayer2.scheduler.RequirementsWatcher;
 import com.google.android.exoplayer2.scheduler.Scheduler;
@@ -71,9 +71,9 @@ public abstract class DownloadService extends Service {
   private static final String TAG = "DownloadService";
   private static final boolean DEBUG = false;
 
-  // Keep the requirements helper for each DownloadService as long as there are tasks (and the
-  // process is running). This allows tasks to resume when there's no scheduler. It may also allow
-  // tasks the resume more quickly than when relying on the scheduler alone.
+  // Keep the requirements helper for each DownloadService as long as there are downloads (and the
+  // process is running). This allows downloads to resume when there's no scheduler. It may also
+  // allow downloads the resume more quickly than when relying on the scheduler alone.
   private static final HashMap<Class<? extends DownloadService>, RequirementsHelper>
       requirementsHelpers = new HashMap<>();
   private static final Requirements DEFAULT_REQUIREMENTS =
@@ -99,7 +99,7 @@ public abstract class DownloadService extends Service {
    * <p>If {@code foregroundNotificationId} isn't {@link #FOREGROUND_NOTIFICATION_ID_NONE} (value
    * {@value #FOREGROUND_NOTIFICATION_ID_NONE}) the service runs in the foreground with {@link
    * #DEFAULT_FOREGROUND_NOTIFICATION_UPDATE_INTERVAL}. In that case {@link
-   * #getForegroundNotification(TaskState[])} should be overridden in the subclass.
+   * #getForegroundNotification(DownloadState[])} should be overridden in the subclass.
    *
    * @param foregroundNotificationId The notification id for the foreground notification, or {@link
    *     #FOREGROUND_NOTIFICATION_ID_NONE} (value {@value #FOREGROUND_NOTIFICATION_ID_NONE})
@@ -110,7 +110,7 @@ public abstract class DownloadService extends Service {
 
   /**
    * Creates a DownloadService which will run in the foreground. {@link
-   * #getForegroundNotification(TaskState[])} should be overridden in the subclass.
+   * #getForegroundNotification(DownloadState[])} should be overridden in the subclass.
    *
    * @param foregroundNotificationId The notification id for the foreground notification, must not
    *     be 0.
@@ -128,7 +128,7 @@ public abstract class DownloadService extends Service {
 
   /**
    * Creates a DownloadService which will run in the foreground. {@link
-   * #getForegroundNotification(TaskState[])} should be overridden in the subclass.
+   * #getForegroundNotification(DownloadState[])} should be overridden in the subclass.
    *
    * @param foregroundNotificationId The notification id for the foreground notification. Must not
    *     be 0.
@@ -338,29 +338,29 @@ public abstract class DownloadService extends Service {
    *
    * <p>Returns a notification to be displayed when this service running in the foreground.
    *
-   * <p>This method is called when there is a task state change and periodically while there are
-   * active tasks. The periodic update interval can be set using {@link #DownloadService(int,
+   * <p>This method is called when there is a download state change and periodically while there are
+   * active downloads. The periodic update interval can be set using {@link #DownloadService(int,
    * long)}.
    *
    * <p>On API level 26 and above, this method may also be called just before the service stops,
-   * with an empty {@code taskStates} array. The returned notification is used to satisfy system
+   * with an empty {@code downloadStates} array. The returned notification is used to satisfy system
    * requirements for foreground services.
    *
-   * @param taskStates The states of all current tasks.
+   * @param downloadStates The states of all current downloads.
    * @return The foreground notification to display.
    */
-  protected Notification getForegroundNotification(TaskState[] taskStates) {
+  protected Notification getForegroundNotification(DownloadState[] downloadStates) {
     throw new IllegalStateException(
         getClass().getName()
             + " is started in the foreground but getForegroundNotification() is not implemented.");
   }
 
   /**
-   * Called when the state of a task changes.
+   * Called when the state of a download changes.
    *
-   * @param taskState The state of the task.
+   * @param downloadState The state of the download.
    */
-  protected void onTaskStateChanged(TaskState taskState) {
+  protected void onDownloadStateChanged(DownloadState downloadState) {
     // Do nothing.
   }
 
@@ -428,10 +428,11 @@ public abstract class DownloadService extends Service {
     }
 
     @Override
-    public void onTaskStateChanged(DownloadManager downloadManager, TaskState taskState) {
-      DownloadService.this.onTaskStateChanged(taskState);
+    public void onDownloadStateChanged(
+        DownloadManager downloadManager, DownloadState downloadState) {
+      DownloadService.this.onDownloadStateChanged(downloadState);
       if (foregroundNotificationUpdater != null) {
-        if (taskState.state == TaskState.STATE_STARTED) {
+        if (downloadState.state == DownloadState.STATE_STARTED) {
           foregroundNotificationUpdater.startPeriodicUpdates();
         } else {
           foregroundNotificationUpdater.update();
@@ -471,8 +472,8 @@ public abstract class DownloadService extends Service {
     }
 
     public void update() {
-      TaskState[] taskStates = downloadManager.getAllTaskStates();
-      startForeground(notificationId, getForegroundNotification(taskStates));
+      DownloadState[] downloadStates = downloadManager.getAllDownloadStates();
+      startForeground(notificationId, getForegroundNotification(downloadStates));
       notificationDisplayed = true;
       if (periodicUpdatesStarted) {
         handler.removeCallbacks(this);

library/core/src/main/java/com/google/android/exoplayer2/offline/FilteringManifestParser.java

@@ -16,22 +16,27 @@
 package com.google.android.exoplayer2.offline;
 
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.upstream.ParsingLoadable.Parser;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
 
-/** A manifest parser that includes only the streams identified by the given stream keys. */
+/**
+ * A manifest parser that includes only the streams identified by the given stream keys.
+ *
+ * @param <T> The {@link FilterableManifest} type.
+ */
 public final class FilteringManifestParser<T extends FilterableManifest<T>> implements Parser<T> {
 
-  private final Parser<T> parser;
-  private final List<StreamKey> streamKeys;
+  private final Parser<? extends T> parser;
+  @Nullable private final List<StreamKey> streamKeys;
 
   /**
    * @param parser A parser for the manifest that will be filtered.
    * @param streamKeys The stream keys. If null or empty then filtering will not occur.
    */
-  public FilteringManifestParser(Parser<T> parser, List<StreamKey> streamKeys) {
+  public FilteringManifestParser(Parser<? extends T> parser, @Nullable List<StreamKey> streamKeys) {
     this.parser = parser;
     this.streamKeys = streamKeys;
   }

library/core/src/main/java/com/google/android/exoplayer2/offline/ProgressiveDownloadHelper.java

@@ -17,19 +17,35 @@ package com.google.android.exoplayer2.offline;
 
 import android.net.Uri;
 import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.Renderer;
 import com.google.android.exoplayer2.source.TrackGroupArray;
-import java.util.Collections;
-import java.util.List;
 
 /** A {@link DownloadHelper} for progressive streams. */
 public final class ProgressiveDownloadHelper extends DownloadHelper<Void> {
 
+  /**
+   * Creates download helper for progressive streams.
+   *
+   * @param uri The stream {@link Uri}.
+   */
   public ProgressiveDownloadHelper(Uri uri) {
-    this(uri, null);
+    this(uri, /* cacheKey= */ null);
   }
 
-  public ProgressiveDownloadHelper(Uri uri, @Nullable String customCacheKey) {
-    super(DownloadAction.TYPE_PROGRESSIVE, uri, customCacheKey);
+  /**
+   * Creates download helper for progressive streams.
+   *
+   * @param uri The stream {@link Uri}.
+   * @param cacheKey An optional cache key.
+   */
+  public ProgressiveDownloadHelper(Uri uri, @Nullable String cacheKey) {
+    super(
+        DownloadAction.TYPE_PROGRESSIVE,
+        uri,
+        cacheKey,
+        DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS,
+        (handler, videoListener, audioListener, metadata, text, drm) -> new Renderer[0],
+        /* drmSessionManager= */ null);
   }
 
   @Override
@@ -43,7 +59,8 @@ public final class ProgressiveDownloadHelper extends DownloadHelper<Void> {
   }
 
   @Override
-  protected List<StreamKey> toStreamKeys(List<TrackKey> trackKeys) {
-    return Collections.emptyList();
+  protected StreamKey toStreamKey(
+      int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup) {
+    return new StreamKey(periodIndex, trackGroupIndex, trackIndexInTrackGroup);
   }
 }

library/core/src/main/java/com/google/android/exoplayer2/offline/StreamKey.java

@@ -19,8 +19,11 @@ import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 
 /**
- * Identifies a given track by the index of the containing period, the index of the containing group
- * within the period, and the index of the track within the group.
+ * A key for a subset of media which can be separately loaded (a "stream").
+ *
+ * <p>The stream key consists of a period index, a group index within the period and a track index
+ * within the group. The interpretation of these indices depends on the type of media for which the
+ * stream key is used.
  */
 public final class StreamKey implements Comparable<StreamKey> {
 

library/core/src/main/java/com/google/android/exoplayer2/offline/TrackKey.java

@@ -1,41 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.android.exoplayer2.offline;
-
-/**
- * Identifies a given track by the index of the containing period, the index of the containing group
- * within the period, and the index of the track within the group.
- */
-public final class TrackKey {
-
-  /** The period index. */
-  public final int periodIndex;
-  /** The group index. */
-  public final int groupIndex;
-  /** The track index. */
-  public final int trackIndex;
-
-  /**
-   * @param periodIndex The period index.
-   * @param groupIndex The group index.
-   * @param trackIndex The track index.
-   */
-  public TrackKey(int periodIndex, int groupIndex, int trackIndex) {
-    this.periodIndex = periodIndex;
-    this.groupIndex = groupIndex;
-    this.trackIndex = trackIndex;
-  }
-}

library/core/src/main/java/com/google/android/exoplayer2/source/ConcatenatingMediaSource.java

@@ -826,7 +826,7 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
 
     public MediaSourceHolder(MediaSource mediaSource) {
       this.mediaSource = mediaSource;
-      this.timeline = new DeferredTimeline();
+      this.timeline = DeferredTimeline.createWithDummyTimeline(mediaSource.getTag());
       this.activeMediaPeriods = new ArrayList<>();
       this.uid = new Object();
     }
@@ -951,10 +951,18 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
   private static final class DeferredTimeline extends ForwardingTimeline {
 
     private static final Object DUMMY_ID = new Object();
-    private static final DummyTimeline DUMMY_TIMELINE = new DummyTimeline();
 
     private final Object replacedId;
 
+    /**
+     * Returns an instance with a dummy timeline using the provided window tag.
+     *
+     * @param windowTag A window tag.
+     */
+    public static DeferredTimeline createWithDummyTimeline(@Nullable Object windowTag) {
+      return new DeferredTimeline(new DummyTimeline(windowTag), DUMMY_ID);
+    }
+
     /**
      * Returns an instance with a real timeline, replacing the provided period ID with the already
      * assigned dummy period ID.
@@ -968,11 +976,6 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
       return new DeferredTimeline(timeline, firstPeriodUid);
     }
 
-    /** Creates deferred timeline exposing a {@link DummyTimeline}. */
-    public DeferredTimeline() {
-      this(DUMMY_TIMELINE, DUMMY_ID);
-    }
-
     private DeferredTimeline(Timeline timeline, Object replacedId) {
       super(timeline);
       this.replacedId = replacedId;
@@ -1016,6 +1019,12 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
   /** Dummy placeholder timeline with one dynamic window with a period of indeterminate duration. */
   private static final class DummyTimeline extends Timeline {
 
+    @Nullable private final Object tag;
+
+    public DummyTimeline(@Nullable Object tag) {
+      this.tag = tag;
+    }
+
     @Override
     public int getWindowCount() {
       return 1;
@@ -1025,7 +1034,7 @@ public class ConcatenatingMediaSource extends CompositeMediaSource<MediaSourceHo
     public Window getWindow(
         int windowIndex, Window window, boolean setTag, long defaultPositionProjectionUs) {
       return window.set(
-          /* tag= */ null,
+          tag,
           /* presentationStartTimeMs= */ C.TIME_UNSET,
           /* windowStartTimeMs= */ C.TIME_UNSET,
           /* isSeekable= */ false,

library/core/src/main/java/com/google/android/exoplayer2/source/MediaPeriod.java

@@ -19,8 +19,11 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
 import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
@@ -83,6 +86,22 @@ public interface MediaPeriod extends SequenceableLoader {
    */
   TrackGroupArray getTrackGroups();
 
+  /**
+   * Returns a list of {@link StreamKey stream keys} which allow to filter the media in this period
+   * to load only the parts needed to play the provided {@link TrackSelection}.
+   *
+   * <p>This method is only called after the period has been prepared.
+   *
+   * @param trackSelection The {@link TrackSelection} describing the tracks for which stream keys
+   *     are requested.
+   * @return The corresponding {@link StreamKey stream keys} for the selected tracks, or an empty
+   *     list if filtering is not possible and the entire media needs to be loaded to play the
+   *     selected tracks.
+   */
+  default List<StreamKey> getStreamKeys(TrackSelection trackSelection) {
+    return Collections.emptyList();
+  }
+
   /**
    * Performs a track selection.
    *

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlDecoder.java

@@ -68,6 +68,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
   private static final String ATTR_END = "end";
   private static final String ATTR_STYLE = "style";
   private static final String ATTR_REGION = "region";
+  private static final String ATTR_IMAGE = "backgroundImage";
 
   private static final Pattern CLOCK_TIME =
       Pattern.compile("^([0-9][0-9]+):([0-9][0-9]):([0-9][0-9])"
@@ -77,6 +78,8 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
   private static final Pattern FONT_SIZE = Pattern.compile("^(([0-9]*.)?[0-9]+)(px|em|%)$");
   private static final Pattern PERCENTAGE_COORDINATES =
       Pattern.compile("^(\\d+\\.?\\d*?)% (\\d+\\.?\\d*?)%$");
+  private static final Pattern PIXEL_COORDINATES =
+      Pattern.compile("^(\\d+\\.?\\d*?)px (\\d+\\.?\\d*?)px$");
   private static final Pattern CELL_RESOLUTION = Pattern.compile("^(\\d+) (\\d+)$");
 
   private static final int DEFAULT_FRAME_RATE = 30;
@@ -105,6 +108,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       XmlPullParser xmlParser = xmlParserFactory.newPullParser();
       Map<String, TtmlStyle> globalStyles = new HashMap<>();
       Map<String, TtmlRegion> regionMap = new HashMap<>();
+      Map<String, String> imageMap = new HashMap<>();
       regionMap.put(TtmlNode.ANONYMOUS_REGION_ID, new TtmlRegion(null));
       ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes, 0, length);
       xmlParser.setInput(inputStream, null);
@@ -114,6 +118,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       int eventType = xmlParser.getEventType();
       FrameAndTickRate frameAndTickRate = DEFAULT_FRAME_AND_TICK_RATE;
       CellResolution cellResolution = DEFAULT_CELL_RESOLUTION;
+      TtsExtent ttsExtent = null;
       while (eventType != XmlPullParser.END_DOCUMENT) {
         TtmlNode parent = nodeStack.peek();
         if (unsupportedNodeDepth == 0) {
@@ -122,12 +127,13 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
             if (TtmlNode.TAG_TT.equals(name)) {
               frameAndTickRate = parseFrameAndTickRates(xmlParser);
               cellResolution = parseCellResolution(xmlParser, DEFAULT_CELL_RESOLUTION);
+              ttsExtent = parseTtsExtent(xmlParser);
             }
             if (!isSupportedTag(name)) {
               Log.i(TAG, "Ignoring unsupported tag: " + xmlParser.getName());
               unsupportedNodeDepth++;
             } else if (TtmlNode.TAG_HEAD.equals(name)) {
-              parseHeader(xmlParser, globalStyles, regionMap, cellResolution);
+              parseHeader(xmlParser, globalStyles, cellResolution, ttsExtent, regionMap, imageMap);
             } else {
               try {
                 TtmlNode node = parseNode(xmlParser, parent, regionMap, frameAndTickRate);
@@ -145,7 +151,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
             parent.addChild(TtmlNode.buildTextNode(xmlParser.getText()));
           } else if (eventType == XmlPullParser.END_TAG) {
             if (xmlParser.getName().equals(TtmlNode.TAG_TT)) {
-              ttmlSubtitle = new TtmlSubtitle(nodeStack.peek(), globalStyles, regionMap);
+              ttmlSubtitle = new TtmlSubtitle(nodeStack.peek(), globalStyles, regionMap, imageMap);
             }
             nodeStack.pop();
           }
@@ -226,11 +232,34 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
     }
   }
 
+  private TtsExtent parseTtsExtent(XmlPullParser xmlParser) {
+    String ttsExtent = XmlPullParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_TTS_EXTENT);
+    if (ttsExtent == null) {
+      return null;
+    }
+
+    Matcher extentMatcher = PIXEL_COORDINATES.matcher(ttsExtent);
+    if (!extentMatcher.matches()) {
+      Log.w(TAG, "Ignoring non-pixel tts extent: " + ttsExtent);
+      return null;
+    }
+    try {
+      int width = Integer.parseInt(extentMatcher.group(1));
+      int height = Integer.parseInt(extentMatcher.group(2));
+      return new TtsExtent(width, height);
+    } catch (NumberFormatException e) {
+      Log.w(TAG, "Ignoring malformed tts extent: " + ttsExtent);
+      return null;
+    }
+  }
+
   private Map<String, TtmlStyle> parseHeader(
       XmlPullParser xmlParser,
       Map<String, TtmlStyle> globalStyles,
+      CellResolution cellResolution,
+      TtsExtent ttsExtent,
       Map<String, TtmlRegion> globalRegions,
-      CellResolution cellResolution)
+      Map<String, String> imageMap)
       throws IOException, XmlPullParserException {
     do {
       xmlParser.next();
@@ -246,23 +275,41 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
           globalStyles.put(style.getId(), style);
         }
       } else if (XmlPullParserUtil.isStartTag(xmlParser, TtmlNode.TAG_REGION)) {
-        TtmlRegion ttmlRegion = parseRegionAttributes(xmlParser, cellResolution);
+        TtmlRegion ttmlRegion = parseRegionAttributes(xmlParser, cellResolution, ttsExtent);
         if (ttmlRegion != null) {
           globalRegions.put(ttmlRegion.id, ttmlRegion);
         }
+      } else if (XmlPullParserUtil.isStartTag(xmlParser, TtmlNode.TAG_METADATA)) {
+        parseMetadata(xmlParser, imageMap);
       }
     } while (!XmlPullParserUtil.isEndTag(xmlParser, TtmlNode.TAG_HEAD));
     return globalStyles;
   }
 
+  private void parseMetadata(XmlPullParser xmlParser, Map<String, String> imageMap)
+      throws IOException, XmlPullParserException {
+    do {
+      xmlParser.next();
+      if (XmlPullParserUtil.isStartTag(xmlParser, TtmlNode.TAG_IMAGE)) {
+        String id = XmlPullParserUtil.getAttributeValue(xmlParser, "id");
+        if (id != null) {
+          String encodedBitmapData = xmlParser.nextText();
+          imageMap.put(id, encodedBitmapData);
+        }
+      }
+    } while (!XmlPullParserUtil.isEndTag(xmlParser, TtmlNode.TAG_METADATA));
+  }
+
   /**
    * Parses a region declaration.
    *
-   * <p>If the region defines an origin and extent, it is required that they're defined as
-   * percentages of the viewport. Region declarations that define origin and extent in other formats
-   * are unsupported, and null is returned.
+   * <p>Supports both percentage and pixel defined regions. In case of pixel defined regions the
+   * passed {@code ttsExtent} is used as a reference window to convert the pixel values to
+   * fractions. In case of missing tts:extent the pixel defined regions can't be parsed, and null is
+   * returned.
    */
-  private TtmlRegion parseRegionAttributes(XmlPullParser xmlParser, CellResolution cellResolution) {
+  private TtmlRegion parseRegionAttributes(
+      XmlPullParser xmlParser, CellResolution cellResolution, TtsExtent ttsExtent) {
     String regionId = XmlPullParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_ID);
     if (regionId == null) {
       return null;
@@ -270,13 +317,30 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
 
     float position;
     float line;
+
     String regionOrigin = XmlPullParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_TTS_ORIGIN);
     if (regionOrigin != null) {
-      Matcher originMatcher = PERCENTAGE_COORDINATES.matcher(regionOrigin);
-      if (originMatcher.matches()) {
+      Matcher originPercentageMatcher = PERCENTAGE_COORDINATES.matcher(regionOrigin);
+      Matcher originPixelMatcher = PIXEL_COORDINATES.matcher(regionOrigin);
+      if (originPercentageMatcher.matches()) {
         try {
-          position = Float.parseFloat(originMatcher.group(1)) / 100f;
-          line = Float.parseFloat(originMatcher.group(2)) / 100f;
+          position = Float.parseFloat(originPercentageMatcher.group(1)) / 100f;
+          line = Float.parseFloat(originPercentageMatcher.group(2)) / 100f;
+        } catch (NumberFormatException e) {
+          Log.w(TAG, "Ignoring region with malformed origin: " + regionOrigin);
+          return null;
+        }
+      } else if (originPixelMatcher.matches()) {
+        if (ttsExtent == null) {
+          Log.w(TAG, "Ignoring region with missing tts:extent: " + regionOrigin);
+          return null;
+        }
+        try {
+          int width = Integer.parseInt(originPixelMatcher.group(1));
+          int height = Integer.parseInt(originPixelMatcher.group(2));
+          // Convert pixel values to fractions.
+          position = width / (float) ttsExtent.width;
+          line = height / (float) ttsExtent.height;
         } catch (NumberFormatException e) {
           Log.w(TAG, "Ignoring region with malformed origin: " + regionOrigin);
           return null;
@@ -299,11 +363,27 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
     float height;
     String regionExtent = XmlPullParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_TTS_EXTENT);
     if (regionExtent != null) {
-      Matcher extentMatcher = PERCENTAGE_COORDINATES.matcher(regionExtent);
-      if (extentMatcher.matches()) {
+      Matcher extentPercentageMatcher = PERCENTAGE_COORDINATES.matcher(regionExtent);
+      Matcher extentPixelMatcher = PIXEL_COORDINATES.matcher(regionExtent);
+      if (extentPercentageMatcher.matches()) {
         try {
-          width = Float.parseFloat(extentMatcher.group(1)) / 100f;
-          height = Float.parseFloat(extentMatcher.group(2)) / 100f;
+          width = Float.parseFloat(extentPercentageMatcher.group(1)) / 100f;
+          height = Float.parseFloat(extentPercentageMatcher.group(2)) / 100f;
+        } catch (NumberFormatException e) {
+          Log.w(TAG, "Ignoring region with malformed extent: " + regionOrigin);
+          return null;
+        }
+      } else if (extentPixelMatcher.matches()) {
+        if (ttsExtent == null) {
+          Log.w(TAG, "Ignoring region with missing tts:extent: " + regionOrigin);
+          return null;
+        }
+        try {
+          int extentWidth = Integer.parseInt(extentPixelMatcher.group(1));
+          int extentHeight = Integer.parseInt(extentPixelMatcher.group(2));
+          // Convert pixel values to fractions.
+          width = extentWidth / (float) ttsExtent.width;
+          height = extentHeight / (float) ttsExtent.height;
         } catch (NumberFormatException e) {
           Log.w(TAG, "Ignoring region with malformed extent: " + regionOrigin);
           return null;
@@ -457,6 +537,7 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
     long startTime = C.TIME_UNSET;
     long endTime = C.TIME_UNSET;
     String regionId = TtmlNode.ANONYMOUS_REGION_ID;
+    String imageId = null;
     String[] styleIds = null;
     int attributeCount = parser.getAttributeCount();
     TtmlStyle style = parseStyleAttributes(parser, null);
@@ -487,6 +568,13 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
             regionId = value;
           }
           break;
+        case ATTR_IMAGE:
+          // Parse URI reference only if refers to an element in the same document (it must start
+          // with '#'). Resolving URIs from external sources is not supported.
+          if (value.startsWith("#")) {
+            imageId = value.substring(1);
+          }
+          break;
         default:
           // Do nothing.
           break;
@@ -509,7 +597,8 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
         endTime = parent.endTimeUs;
       }
     }
-    return TtmlNode.buildNode(parser.getName(), startTime, endTime, style, styleIds, regionId);
+    return TtmlNode.buildNode(
+        parser.getName(), startTime, endTime, style, styleIds, regionId, imageId);
   }
 
   private static boolean isSupportedTag(String tag) {
@@ -525,9 +614,9 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
         || tag.equals(TtmlNode.TAG_LAYOUT)
         || tag.equals(TtmlNode.TAG_REGION)
         || tag.equals(TtmlNode.TAG_METADATA)
-        || tag.equals(TtmlNode.TAG_SMPTE_IMAGE)
-        || tag.equals(TtmlNode.TAG_SMPTE_DATA)
-        || tag.equals(TtmlNode.TAG_SMPTE_INFORMATION);
+        || tag.equals(TtmlNode.TAG_IMAGE)
+        || tag.equals(TtmlNode.TAG_DATA)
+        || tag.equals(TtmlNode.TAG_INFORMATION);
   }
 
   private static void parseFontSize(String expression, TtmlStyle out) throws
@@ -651,4 +740,15 @@ public final class TtmlDecoder extends SimpleSubtitleDecoder {
       this.rows = rows;
     }
   }
+
+  /** Represents the tts:extent for a TTML file. */
+  private static final class TtsExtent {
+    final int width;
+    final int height;
+
+    TtsExtent(int width, int height) {
+      this.width = width;
+      this.height = height;
+    }
+  }
 }

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlNode.java

@@ -15,7 +15,12 @@
  */
 package com.google.android.exoplayer2.text.ttml;
 
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.support.annotation.Nullable;
 import android.text.SpannableStringBuilder;
+import android.util.Base64;
+import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.util.Assertions;
@@ -44,9 +49,9 @@ import java.util.TreeSet;
   public static final String TAG_LAYOUT = "layout";
   public static final String TAG_REGION = "region";
   public static final String TAG_METADATA = "metadata";
-  public static final String TAG_SMPTE_IMAGE = "smpte:image";
-  public static final String TAG_SMPTE_DATA = "smpte:data";
-  public static final String TAG_SMPTE_INFORMATION = "smpte:information";
+  public static final String TAG_IMAGE = "image";
+  public static final String TAG_DATA = "data";
+  public static final String TAG_INFORMATION = "information";
 
   public static final String ANONYMOUS_REGION_ID = "";
   public static final String ATTR_ID = "id";
@@ -75,34 +80,57 @@ import java.util.TreeSet;
   public static final String START = "start";
   public static final String END = "end";
 
-  public final String tag;
-  public final String text;
+  @Nullable public final String tag;
+  @Nullable public final String text;
   public final boolean isTextNode;
   public final long startTimeUs;
   public final long endTimeUs;
-  public final TtmlStyle style;
+  @Nullable public final TtmlStyle style;
+  @Nullable private final String[] styleIds;
   public final String regionId;
+  @Nullable public final String imageId;
 
-  private final String[] styleIds;
   private final HashMap<String, Integer> nodeStartsByRegion;
   private final HashMap<String, Integer> nodeEndsByRegion;
 
   private List<TtmlNode> children;
 
   public static TtmlNode buildTextNode(String text) {
-    return new TtmlNode(null, TtmlRenderUtil.applyTextElementSpacePolicy(text), C.TIME_UNSET,
-        C.TIME_UNSET, null, null, ANONYMOUS_REGION_ID);
+    return new TtmlNode(
+        /* tag= */ null,
+        TtmlRenderUtil.applyTextElementSpacePolicy(text),
+        /* startTimeUs= */ C.TIME_UNSET,
+        /* endTimeUs= */ C.TIME_UNSET,
+        /* style= */ null,
+        /* styleIds= */ null,
+        ANONYMOUS_REGION_ID,
+        /* imageId= */ null);
   }
 
-  public static TtmlNode buildNode(String tag, long startTimeUs, long endTimeUs,
-      TtmlStyle style, String[] styleIds, String regionId) {
-    return new TtmlNode(tag, null, startTimeUs, endTimeUs, style, styleIds, regionId);
+  public static TtmlNode buildNode(
+      @Nullable String tag,
+      long startTimeUs,
+      long endTimeUs,
+      @Nullable TtmlStyle style,
+      @Nullable String[] styleIds,
+      String regionId,
+      @Nullable String imageId) {
+    return new TtmlNode(
+        tag, /* text= */ null, startTimeUs, endTimeUs, style, styleIds, regionId, imageId);
   }
 
-  private TtmlNode(String tag, String text, long startTimeUs, long endTimeUs,
-      TtmlStyle style, String[] styleIds, String regionId) {
+  private TtmlNode(
+      @Nullable String tag,
+      @Nullable String text,
+      long startTimeUs,
+      long endTimeUs,
+      @Nullable TtmlStyle style,
+      @Nullable String[] styleIds,
+      String regionId,
+      @Nullable String imageId) {
     this.tag = tag;
     this.text = text;
+    this.imageId = imageId;
     this.style = style;
     this.styleIds = styleIds;
     this.isTextNode = text != null;
@@ -151,7 +179,8 @@ import java.util.TreeSet;
 
   private void getEventTimes(TreeSet<Long> out, boolean descendsPNode) {
     boolean isPNode = TAG_P.equals(tag);
-    if (descendsPNode || isPNode) {
+    boolean isDivNode = TAG_DIV.equals(tag);
+    if (descendsPNode || isPNode || (isDivNode && imageId != null)) {
       if (startTimeUs != C.TIME_UNSET) {
         out.add(startTimeUs);
       }
@@ -171,13 +200,46 @@ import java.util.TreeSet;
     return styleIds;
   }
 
-  public List<Cue> getCues(long timeUs, Map<String, TtmlStyle> globalStyles,
-      Map<String, TtmlRegion> regionMap) {
-    TreeMap<String, SpannableStringBuilder> regionOutputs = new TreeMap<>();
-    traverseForText(timeUs, false, regionId, regionOutputs);
-    traverseForStyle(timeUs, globalStyles, regionOutputs);
+  public List<Cue> getCues(
+      long timeUs,
+      Map<String, TtmlStyle> globalStyles,
+      Map<String, TtmlRegion> regionMap,
+      Map<String, String> imageMap) {
+
+    List<Pair<String, String>> regionImageOutputs = new ArrayList<>();
+    traverseForImage(timeUs, regionId, regionImageOutputs);
+
+    TreeMap<String, SpannableStringBuilder> regionTextOutputs = new TreeMap<>();
+    traverseForText(timeUs, false, regionId, regionTextOutputs);
+    traverseForStyle(timeUs, globalStyles, regionTextOutputs);
+
     List<Cue> cues = new ArrayList<>();
-    for (Entry<String, SpannableStringBuilder> entry : regionOutputs.entrySet()) {
+
+    // Create image based cues.
+    for (Pair<String, String> regionImagePair : regionImageOutputs) {
+      String encodedBitmapData = imageMap.get(regionImagePair.second);
+      if (encodedBitmapData == null) {
+        // Image reference points to an invalid image. Do nothing.
+        continue;
+      }
+
+      byte[] bitmapData = Base64.decode(encodedBitmapData, Base64.DEFAULT);
+      Bitmap bitmap = BitmapFactory.decodeByteArray(bitmapData, /* offset= */ 0, bitmapData.length);
+      TtmlRegion region = regionMap.get(regionImagePair.first);
+
+      cues.add(
+          new Cue(
+              bitmap,
+              region.position,
+              Cue.ANCHOR_TYPE_MIDDLE,
+              region.line,
+              region.lineAnchor,
+              region.width,
+              /* height= */ Cue.DIMEN_UNSET));
+    }
+
+    // Create text based cues.
+    for (Entry<String, SpannableStringBuilder> entry : regionTextOutputs.entrySet()) {
       TtmlRegion region = regionMap.get(entry.getKey());
       cues.add(
           new Cue(
@@ -192,9 +254,22 @@ import java.util.TreeSet;
               region.textSizeType,
               region.textSize));
     }
+
     return cues;
   }
 
+  private void traverseForImage(
+      long timeUs, String inheritedRegion, List<Pair<String, String>> regionImageList) {
+    String resolvedRegionId = ANONYMOUS_REGION_ID.equals(regionId) ? inheritedRegion : regionId;
+    if (isActive(timeUs) && TAG_DIV.equals(tag) && imageId != null) {
+      regionImageList.add(new Pair<>(resolvedRegionId, imageId));
+      return;
+    }
+    for (int i = 0; i < getChildCount(); ++i) {
+      getChild(i).traverseForImage(timeUs, resolvedRegionId, regionImageList);
+    }
+  }
+
   private void traverseForText(
       long timeUs,
       boolean descendsPNode,

library/core/src/main/java/com/google/android/exoplayer2/text/ttml/TtmlSubtitle.java

@@ -33,11 +33,16 @@ import java.util.Map;
   private final long[] eventTimesUs;
   private final Map<String, TtmlStyle> globalStyles;
   private final Map<String, TtmlRegion> regionMap;
+  private final Map<String, String> imageMap;
 
-  public TtmlSubtitle(TtmlNode root, Map<String, TtmlStyle> globalStyles,
-      Map<String, TtmlRegion> regionMap) {
+  public TtmlSubtitle(
+      TtmlNode root,
+      Map<String, TtmlStyle> globalStyles,
+      Map<String, TtmlRegion> regionMap,
+      Map<String, String> imageMap) {
     this.root = root;
     this.regionMap = regionMap;
+    this.imageMap = imageMap;
     this.globalStyles =
         globalStyles != null ? Collections.unmodifiableMap(globalStyles) : Collections.emptyMap();
     this.eventTimesUs = root.getEventTimesUs();
@@ -66,7 +71,7 @@ import java.util.Map;
 
   @Override
   public List<Cue> getCues(long timeUs) {
-    return root.getCues(timeUs, globalStyles, regionMap);
+    return root.getCues(timeUs, globalStyles, regionMap, imageMap);
   }
 
   @VisibleForTesting

library/core/src/main/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelection.java

@@ -227,8 +227,36 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
     }
 
     @Override
-    public AdaptiveTrackSelection createTrackSelection(
-        TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks) {
+    public @NullableType TrackSelection[] createTrackSelections(
+        @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
+      TrackSelection[] selections = new TrackSelection[definitions.length];
+      AdaptiveTrackSelection adaptiveSelection = null;
+      int totalFixedBandwidth = 0;
+      for (int i = 0; i < definitions.length; i++) {
+        Definition definition = definitions[i];
+        if (definition == null) {
+          continue;
+        }
+        if (definition.tracks.length > 1) {
+          adaptiveSelection =
+              createAdaptiveTrackSelection(definition.group, bandwidthMeter, definition.tracks);
+          selections[i] = adaptiveSelection;
+        } else {
+          selections[i] = new FixedTrackSelection(definition.group, definition.tracks[0]);
+          int trackBitrate = definition.group.getFormat(definition.tracks[0]).bitrate;
+          if (trackBitrate != Format.NO_VALUE) {
+            totalFixedBandwidth += trackBitrate;
+          }
+        }
+      }
+      if (blockFixedTrackSelectionBandwidth && adaptiveSelection != null) {
+        adaptiveSelection.experimental_setNonAllocatableBandwidth(totalFixedBandwidth);
+      }
+      return selections;
+    }
+
+    private AdaptiveTrackSelection createAdaptiveTrackSelection(
+        TrackGroup group, BandwidthMeter bandwidthMeter, int[] tracks) {
       if (this.bandwidthMeter != null) {
         bandwidthMeter = this.bandwidthMeter;
       }
@@ -246,34 +274,6 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
       adaptiveTrackSelection.experimental_setTrackBitrateEstimator(trackBitrateEstimator);
       return adaptiveTrackSelection;
     }
-
-    @Override
-    public @NullableType TrackSelection[] createTrackSelections(
-        @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
-      TrackSelection[] selections = new TrackSelection[definitions.length];
-      AdaptiveTrackSelection adaptiveSelection = null;
-      int totalFixedBandwidth = 0;
-      for (int i = 0; i < definitions.length; i++) {
-        Definition definition = definitions[i];
-        if (definition == null) {
-          continue;
-        }
-        if (definition.tracks.length > 1) {
-          selections[i] = createTrackSelection(definition.group, bandwidthMeter, definition.tracks);
-          adaptiveSelection = (AdaptiveTrackSelection) selections[i];
-        } else {
-          selections[i] = new FixedTrackSelection(definition.group, definition.tracks[0]);
-          int trackBitrate = definition.group.getFormat(definition.tracks[0]).bitrate;
-          if (trackBitrate != Format.NO_VALUE) {
-            totalFixedBandwidth += trackBitrate;
-          }
-        }
-      }
-      if (blockFixedTrackSelectionBandwidth && adaptiveSelection != null) {
-        adaptiveSelection.experimental_setNonAllocatableBandwidth(totalFixedBandwidth);
-      }
-      return selections;
-    }
   }
 
   public static final int DEFAULT_MIN_DURATION_FOR_QUALITY_INCREASE_MS = 10000;

library/core/src/main/java/com/google/android/exoplayer2/trackselection/BufferSizeAdaptationBuilder.java

@@ -24,12 +24,14 @@ import com.google.android.exoplayer2.LoadControl;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
+import com.google.android.exoplayer2.trackselection.TrackSelection.Definition;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.upstream.DefaultAllocator;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Clock;
 import com.google.android.exoplayer2.util.PriorityTaskManager;
 import java.util.List;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
  * Builder for a {@link TrackSelection.Factory} and {@link LoadControl} that implement buffer size
@@ -273,19 +275,22 @@ public final class BufferSizeAdaptationBuilder {
     TrackSelection.Factory trackSelectionFactory =
         new TrackSelection.Factory() {
           @Override
-          public TrackSelection createTrackSelection(
-              TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks) {
-            return new BufferSizeAdaptiveTrackSelection(
-                group,
-                tracks,
-                bandwidthMeter,
-                minBufferMs,
-                maxBufferMs,
-                hysteresisBufferMs,
-                startUpBandwidthFraction,
-                startUpMinBufferForQualityIncreaseMs,
-                dynamicFormatFilter,
-                clock);
+          public @NullableType TrackSelection[] createTrackSelections(
+              @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
+            return TrackSelectionUtil.createTrackSelectionsForDefinitions(
+                definitions,
+                definition ->
+                    new BufferSizeAdaptiveTrackSelection(
+                        definition.group,
+                        definition.tracks,
+                        bandwidthMeter,
+                        minBufferMs,
+                        maxBufferMs,
+                        hysteresisBufferMs,
+                        startUpBandwidthFraction,
+                        startUpMinBufferForQualityIncreaseMs,
+                        dynamicFormatFilter,
+                        clock));
           }
         };
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/FixedTrackSelection.java

@@ -21,8 +21,8 @@ import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
-import com.google.android.exoplayer2.util.Assertions;
 import java.util.List;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
  * A {@link TrackSelection} consisting of a single track.
@@ -56,10 +56,12 @@ public final class FixedTrackSelection extends BaseTrackSelection {
     }
 
     @Override
-    public FixedTrackSelection createTrackSelection(
-        TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks) {
-      Assertions.checkArgument(tracks.length == 1);
-      return new FixedTrackSelection(group, tracks[0], reason, data);
+    public @NullableType TrackSelection[] createTrackSelections(
+        @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
+      return TrackSelectionUtil.createTrackSelectionsForDefinitions(
+          definitions,
+          definition ->
+              new FixedTrackSelection(definition.group, definition.tracks[0], reason, data));
     }
   }
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/RandomTrackSelection.java

@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import java.util.List;
 import java.util.Random;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
  * A {@link TrackSelection} whose selected track is updated randomly.
@@ -49,9 +50,11 @@ public final class RandomTrackSelection extends BaseTrackSelection {
     }
 
     @Override
-    public RandomTrackSelection createTrackSelection(
-        TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks) {
-      return new RandomTrackSelection(group, tracks, random);
+    public @NullableType TrackSelection[] createTrackSelections(
+        @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
+      return TrackSelectionUtil.createTrackSelectionsForDefinitions(
+          definitions,
+          definition -> new RandomTrackSelection(definition.group, definition.tracks, random));
     }
   }
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/TrackSelection.java

@@ -21,8 +21,8 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
+import com.google.android.exoplayer2.trackselection.TrackSelectionUtil.AdaptiveTrackSelectionFactory;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
-import com.google.android.exoplayer2.util.Assertions;
 import java.util.List;
 import org.checkerframework.checker.nullness.compatqual.NullableType;
 
@@ -61,42 +61,31 @@ public interface TrackSelection {
   interface Factory {
 
     /**
-     * Creates a new selection.
-     *
-     * @param group The {@link TrackGroup}. Must not be null.
-     * @param bandwidthMeter A {@link BandwidthMeter} which can be used to select tracks.
-     * @param tracks The indices of the selected tracks within the {@link TrackGroup}. Must not be
-     *     null or empty. May be in any order.
-     * @return The created selection.
+     * @deprecated Implement {@link #createTrackSelections(Definition[], BandwidthMeter)} instead.
+     *     Calling {@link TrackSelectionUtil#createTrackSelectionsForDefinitions(Definition[],
+     *     AdaptiveTrackSelectionFactory)} helps to create a single adaptive track selection in the
+     *     same way as using this deprecated method.
      */
-    TrackSelection createTrackSelection(
-        TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks);
+    @Deprecated
+    default TrackSelection createTrackSelection(
+        TrackGroup group, BandwidthMeter bandwidthMeter, int... tracks) {
+      throw new UnsupportedOperationException();
+    }
 
     /**
      * Creates a new selection for each {@link Definition}.
      *
      * @param definitions A {@link Definition} array. May include null values.
      * @param bandwidthMeter A {@link BandwidthMeter} which can be used to select tracks.
-     * @return The created selections. For null entries in {@code definitions} returns null values.
+     * @return The created selections. Must have the same length as {@code definitions} and may
+     *     include null values.
      */
+    @SuppressWarnings("deprecation")
     default @NullableType TrackSelection[] createTrackSelections(
         @NullableType Definition[] definitions, BandwidthMeter bandwidthMeter) {
-      TrackSelection[] selections = new TrackSelection[definitions.length];
-      boolean createdAdaptiveTrackSelection = false;
-      for (int i = 0; i < definitions.length; i++) {
-        Definition definition = definitions[i];
-        if (definition == null) {
-          continue;
-        }
-        if (definition.tracks.length > 1) {
-          Assertions.checkState(!createdAdaptiveTrackSelection);
-          createdAdaptiveTrackSelection = true;
-          selections[i] = createTrackSelection(definition.group, bandwidthMeter, definition.tracks);
-        } else {
-          selections[i] = new FixedTrackSelection(definition.group, definition.tracks[0]);
-        }
-      }
-      return selections;
+      return TrackSelectionUtil.createTrackSelectionsForDefinitions(
+          definitions,
+          definition -> createTrackSelection(definition.group, bandwidthMeter, definition.tracks));
     }
   }
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/TrackSelectionUtil.java

@@ -22,15 +22,59 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
 import com.google.android.exoplayer2.source.chunk.MediaChunkListIterator;
+import com.google.android.exoplayer2.trackselection.TrackSelection.Definition;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.Arrays;
 import java.util.List;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /** Track selection related utility methods. */
 public final class TrackSelectionUtil {
 
   private TrackSelectionUtil() {}
 
+  /** Functional interface to create a single adaptive track selection. */
+  public interface AdaptiveTrackSelectionFactory {
+
+    /**
+     * Creates an adaptive track selection for the provided track selection definition.
+     *
+     * @param trackSelectionDefinition A {@link Definition} for the track selection.
+     * @return The created track selection.
+     */
+    TrackSelection createAdaptiveTrackSelection(Definition trackSelectionDefinition);
+  }
+
+  /**
+   * Creates track selections for an array of track selection definitions, with at most one
+   * multi-track adaptive selection.
+   *
+   * @param definitions The list of track selection {@link Definition definitions}. May include null
+   *     values.
+   * @param adaptiveTrackSelectionFactory A factory for the multi-track adaptive track selection.
+   * @return The array of created track selection. For null entries in {@code definitions} returns
+   *     null values.
+   */
+  public static @NullableType TrackSelection[] createTrackSelectionsForDefinitions(
+      @NullableType Definition[] definitions,
+      AdaptiveTrackSelectionFactory adaptiveTrackSelectionFactory) {
+    TrackSelection[] selections = new TrackSelection[definitions.length];
+    boolean createdAdaptiveTrackSelection = false;
+    for (int i = 0; i < definitions.length; i++) {
+      Definition definition = definitions[i];
+      if (definition == null) {
+        continue;
+      }
+      if (definition.tracks.length > 1 && !createdAdaptiveTrackSelection) {
+        createdAdaptiveTrackSelection = true;
+        selections[i] = adaptiveTrackSelectionFactory.createAdaptiveTrackSelection(definition);
+      } else {
+        selections[i] = new FixedTrackSelection(definition.group, definition.tracks[0]);
+      }
+    }
+    return selections;
+  }
+
   /**
    * Returns average bitrate for chunks in bits per second. Chunks are included in average until
    * {@code maxDurationMs} or the first unknown length chunk.

library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSpec.java

@@ -108,10 +108,7 @@ public final class DataSpec {
    * {@link DataSpec} is not intended to be used in conjunction with a cache.
    */
   public final @Nullable String key;
-  /**
-   * Request flags. Currently {@link #FLAG_ALLOW_GZIP} and
-   * {@link #FLAG_ALLOW_CACHING_UNKNOWN_LENGTH} are the only supported flags.
-   */
+  /** Request {@link Flags flags}. */
   public final @Flags int flags;
 
   /**

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/Cache.java

@@ -62,7 +62,7 @@ public interface Cache {
     void onSpanTouched(Cache cache, CacheSpan oldSpan, CacheSpan newSpan);
 
   }
-  
+
   /**
    * Thrown when an error is encountered when writing data.
    */
@@ -82,7 +82,7 @@ public interface Cache {
    * Releases the cache. This method must be called when the cache is no longer required. The cache
    * must not be used after calling this method.
    */
-  void release() throws CacheException;
+  void release();
 
   /**
    * Registers a listener to listen for changes to a given key.
@@ -223,25 +223,6 @@ public interface Cache {
    */
   long getCachedLength(String key, long position, long length);
 
-  /**
-   * Sets the content length for the given key.
-   *
-   * @param key The cache key for the data.
-   * @param length The length of the data.
-   * @throws CacheException If an error is encountered.
-   */
-  void setContentLength(String key, long length) throws CacheException;
-
-  /**
-   * Returns the content length for the given key if one set, or {@link
-   * com.google.android.exoplayer2.C#LENGTH_UNSET} otherwise.
-   *
-   * @param key The cache key for the data.
-   * @return The content length for the given key if one set, or {@link
-   *     com.google.android.exoplayer2.C#LENGTH_UNSET} otherwise.
-   */
-  long getContentLength(String key);
-
   /**
    * Applies {@code mutations} to the {@link ContentMetadata} for the given key. A new {@link
    * CachedContent} is added if there isn't one already with the given key.

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java

@@ -42,10 +42,6 @@ import java.util.Map;
  * A {@link DataSource} that reads and writes a {@link Cache}. Requests are fulfilled from the cache
  * when possible. When data is not cached it is requested from an upstream {@link DataSource} and
  * written into the cache.
- *
- * <p>By default requests whose length can not be resolved are not cached. This is to prevent
- * caching of progressive live streams, which should usually not be cached. Caching of this kind of
- * requests can be enabled per request with {@link DataSpec#FLAG_ALLOW_CACHING_UNKNOWN_LENGTH}.
  */
 public final class CacheDataSource implements DataSource {
 
@@ -303,7 +299,7 @@ public final class CacheDataSource implements DataSource {
       if (dataSpec.length != C.LENGTH_UNSET || currentRequestIgnoresCache) {
         bytesRemaining = dataSpec.length;
       } else {
-        bytesRemaining = cache.getContentLength(key);
+        bytesRemaining = ContentMetadata.getContentLength(cache.getContentMetadata(key));
         if (bytesRemaining != C.LENGTH_UNSET) {
           bytesRemaining -= dataSpec.position;
           if (bytesRemaining <= 0) {
@@ -488,16 +484,12 @@ public final class CacheDataSource implements DataSource {
     ContentMetadataMutations mutations = new ContentMetadataMutations();
     if (currentDataSpecLengthUnset && resolvedLength != C.LENGTH_UNSET) {
       bytesRemaining = resolvedLength;
-      ContentMetadataInternal.setContentLength(mutations, readPosition + bytesRemaining);
+      ContentMetadataMutations.setContentLength(mutations, readPosition + bytesRemaining);
     }
     if (isReadingFromUpstream()) {
       actualUri = currentDataSource.getUri();
       boolean isRedirected = !uri.equals(actualUri);
-      if (isRedirected) {
-        ContentMetadataInternal.setRedirectedUri(mutations, actualUri);
-      } else {
-        ContentMetadataInternal.removeRedirectedUri(mutations);
-      }
+      ContentMetadataMutations.setRedirectedUri(mutations, isRedirected ? actualUri : null);
     }
     if (isWritingToCache()) {
       cache.applyContentMetadataMutations(key, mutations);
@@ -507,14 +499,15 @@ public final class CacheDataSource implements DataSource {
   private void setNoBytesRemainingAndMaybeStoreLength() throws IOException {
     bytesRemaining = 0;
     if (isWritingToCache()) {
-      cache.setContentLength(key, readPosition);
+      ContentMetadataMutations mutations = new ContentMetadataMutations();
+      ContentMetadataMutations.setContentLength(mutations, readPosition);
+      cache.applyContentMetadataMutations(key, mutations);
     }
   }
 
   private static Uri getRedirectedUriOrDefault(Cache cache, String key, Uri defaultUri) {
-    ContentMetadata contentMetadata = cache.getContentMetadata(key);
-    Uri redirectedUri = ContentMetadataInternal.getRedirectedUri(contentMetadata);
-    return redirectedUri == null ? defaultUri : redirectedUri;
+    Uri redirectedUri = ContentMetadata.getRedirectedUri(cache.getContentMetadata(key));
+    return redirectedUri != null ? redirectedUri : defaultUri;
   }
 
   private static boolean isCausedByPositionOutOfRange(IOException e) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheUtil.java

@@ -84,7 +84,10 @@ public final class CacheUtil {
       CachingCounters counters) {
     String key = buildCacheKey(dataSpec, cacheKeyFactory);
     long start = dataSpec.absoluteStreamPosition;
-    long left = dataSpec.length != C.LENGTH_UNSET ? dataSpec.length : cache.getContentLength(key);
+    long left =
+        dataSpec.length != C.LENGTH_UNSET
+            ? dataSpec.length
+            : ContentMetadata.getContentLength(cache.getContentMetadata(key));
     counters.contentLength = left;
     counters.alreadyCachedBytes = 0;
     counters.newlyCachedBytes = 0;
@@ -188,7 +191,10 @@ public final class CacheUtil {
 
     String key = buildCacheKey(dataSpec, cacheKeyFactory);
     long start = dataSpec.absoluteStreamPosition;
-    long left = dataSpec.length != C.LENGTH_UNSET ? dataSpec.length : cache.getContentLength(key);
+    long left =
+        dataSpec.length != C.LENGTH_UNSET
+            ? dataSpec.length
+            : ContentMetadata.getContentLength(cache.getContentMetadata(key));
     while (left != 0) {
       throwExceptionIfInterruptedOrCancelled(isCanceled);
       long blockLength =

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedContent.java

@@ -55,7 +55,7 @@ import java.util.TreeSet;
     if (version < VERSION_METADATA_INTRODUCED) {
       long length = input.readLong();
       ContentMetadataMutations mutations = new ContentMetadataMutations();
-      ContentMetadataInternal.setContentLength(mutations, length);
+      ContentMetadataMutations.setContentLength(mutations, length);
       cachedContent.applyMetadataMutations(mutations);
     } else {
       cachedContent.metadata = DefaultContentMetadata.readFromStream(input);
@@ -216,7 +216,7 @@ import java.util.TreeSet;
     int result = id;
     result = 31 * result + key.hashCode();
     if (version < VERSION_METADATA_INTRODUCED) {
-      long length = ContentMetadataInternal.getContentLength(metadata);
+      long length = ContentMetadata.getContentLength(metadata);
       result = 31 * result + (int) (length ^ (length >>> 32));
     } else {
       result = 31 * result + metadata.hashCode();

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedContentIndex.java

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.upstream.cache;
 
 import android.support.annotation.VisibleForTesting;
 import android.util.SparseArray;
+import android.util.SparseBooleanArray;
 import com.google.android.exoplayer2.upstream.cache.Cache.CacheException;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.AtomicFile;
@@ -42,6 +43,7 @@ import javax.crypto.CipherOutputStream;
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /** Maintains the index of cached content. */
 /* package */ class CachedContentIndex {
@@ -53,7 +55,30 @@ import javax.crypto.spec.SecretKeySpec;
   private static final int FLAG_ENCRYPTED_INDEX = 1;
 
   private final HashMap<String, CachedContent> keyToContent;
-  private final SparseArray<String> idToKey;
+  /**
+   * Maps assigned ids to their corresponding keys. Also contains (id -> null) entries for ids that
+   * have been removed from the index since it was last stored. This prevents reuse of these ids,
+   * which is necessary to avoid clashes that could otherwise occur as a result of the sequence:
+   *
+   * <p>[1] (key1, id1) is removed from the in-memory index ... the index is not stored to disk ...
+   * [2] id1 is reused for a different key2 ... the index is not stored to disk ... [3] A file for
+   * key2 is partially written using a path corresponding to id1 ... the process is killed before
+   * the index is stored to disk ... [4] The index is read from disk, causing the partially written
+   * file to be incorrectly associated to key1
+   *
+   * <p>By avoiding id reuse in step [2], a new id2 will be used instead. Step [4] will then delete
+   * the partially written file because the index does not contain an entry for id2.
+   *
+   * <p>When the index is next stored (id -> null) entries are removed, making the ids eligible for
+   * reuse.
+   */
+  private final SparseArray<@NullableType String> idToKey;
+  /**
+   * Tracks ids for which (id -> null) entries are present in idToKey, so that they can be removed
+   * efficiently when the index is next stored.
+   */
+  private final SparseBooleanArray removedIds;
+
   private final AtomicFile atomicFile;
   private final Cipher cipher;
   private final SecretKeySpec secretKeySpec;
@@ -105,6 +130,7 @@ import javax.crypto.spec.SecretKeySpec;
     }
     keyToContent = new HashMap<>();
     idToKey = new SparseArray<>();
+    removedIds = new SparseBooleanArray();
     atomicFile = new AtomicFile(new File(cacheDir, FILE_NAME));
   }
 
@@ -125,6 +151,12 @@ import javax.crypto.spec.SecretKeySpec;
     }
     writeFile();
     changed = false;
+    // Make ids that were removed since the index was last stored eligible for re-use.
+    int removedIdCount = removedIds.size();
+    for (int i = 0; i < removedIdCount; i++) {
+      idToKey.remove(removedIds.keyAt(i));
+    }
+    removedIds.clear();
   }
 
   /**
@@ -169,8 +201,11 @@ import javax.crypto.spec.SecretKeySpec;
     CachedContent cachedContent = keyToContent.get(key);
     if (cachedContent != null && cachedContent.isEmpty() && !cachedContent.isLocked()) {
       keyToContent.remove(key);
-      idToKey.remove(cachedContent.id);
       changed = true;
+      // Keep an entry in idToKey to stop the id from being reused until the index is next stored.
+      idToKey.put(cachedContent.id, /* value= */ null);
+      // Track that the entry should be removed from idToKey when the index is next stored.
+      removedIds.put(cachedContent.id, /* value= */ true);
     }
   }
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/ContentMetadata.java

@@ -15,44 +15,73 @@
  */
 package com.google.android.exoplayer2.upstream.cache;
 
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+
 /**
  * Interface for an immutable snapshot of keyed metadata.
- *
- * <p>Internal metadata names are prefixed with {@value #INTERNAL_METADATA_NAME_PREFIX}. Custom
- * metadata names should avoid this prefix to prevent clashes.
  */
 public interface ContentMetadata {
 
-  /** Prefix of internal metadata names. */
-  String INTERNAL_METADATA_NAME_PREFIX = "exo_";
+  /**
+   * Prefix for custom metadata keys. Applications can use keys starting with this prefix without
+   * any risk of their keys colliding with ones defined by the ExoPlayer library.
+   */
+  @SuppressWarnings("unused")
+  String KEY_CUSTOM_PREFIX = "custom_";
+  /** Key for redirected uri (type: String). */
+  String KEY_REDIRECTED_URI = "exo_redir";
+  /** Key for content length in bytes (type: long). */
+  String KEY_CONTENT_LENGTH = "exo_len";
 
   /**
    * Returns a metadata value.
    *
-   * @param name Name of the metadata to be returned.
+   * @param key Key of the metadata to be returned.
    * @param defaultValue Value to return if the metadata doesn't exist.
    * @return The metadata value.
    */
-  byte[] get(String name, byte[] defaultValue);
+  @Nullable
+  byte[] get(String key, @Nullable byte[] defaultValue);
 
   /**
    * Returns a metadata value.
    *
-   * @param name Name of the metadata to be returned.
+   * @param key Key of the metadata to be returned.
    * @param defaultValue Value to return if the metadata doesn't exist.
    * @return The metadata value.
    */
-  String get(String name, String defaultValue);
+  @Nullable
+  String get(String key, @Nullable String defaultValue);
 
   /**
    * Returns a metadata value.
    *
-   * @param name Name of the metadata to be returned.
+   * @param key Key of the metadata to be returned.
    * @param defaultValue Value to return if the metadata doesn't exist.
    * @return The metadata value.
    */
-  long get(String name, long defaultValue);
+  long get(String key, long defaultValue);
 
   /** Returns whether the metadata is available. */
-  boolean contains(String name);
+  boolean contains(String key);
+
+  /**
+   * Returns the value stored under {@link #KEY_CONTENT_LENGTH}, or {@link C#LENGTH_UNSET} if not
+   * set.
+   */
+  static long getContentLength(ContentMetadata contentMetadata) {
+    return contentMetadata.get(KEY_CONTENT_LENGTH, C.LENGTH_UNSET);
+  }
+
+  /**
+   * Returns the value stored under {@link #KEY_REDIRECTED_URI} as a {@link Uri}, or {code null} if
+   * not set.
+   */
+  @Nullable
+  static Uri getRedirectedUri(ContentMetadata contentMetadata) {
+    String redirectedUri = contentMetadata.get(KEY_REDIRECTED_URI, (String) null);
+    return redirectedUri == null ? null : Uri.parse(redirectedUri);
+  }
 }

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/ContentMetadataInternal.java

@@ -1,66 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.android.exoplayer2.upstream.cache;
-
-import android.net.Uri;
-import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.C;
-
-/** Helper classes to easily access and modify internal metadata values. */
-/* package */ final class ContentMetadataInternal {
-
-  private static final String PREFIX = ContentMetadata.INTERNAL_METADATA_NAME_PREFIX;
-  private static final String METADATA_NAME_REDIRECTED_URI = PREFIX + "redir";
-  private static final String METADATA_NAME_CONTENT_LENGTH = PREFIX + "len";
-
-  /** Returns the content length metadata, or {@link C#LENGTH_UNSET} if not set. */
-  public static long getContentLength(ContentMetadata contentMetadata) {
-    return contentMetadata.get(METADATA_NAME_CONTENT_LENGTH, C.LENGTH_UNSET);
-  }
-
-  /** Adds a mutation to set content length metadata value. */
-  public static void setContentLength(ContentMetadataMutations mutations, long length) {
-    mutations.set(METADATA_NAME_CONTENT_LENGTH, length);
-  }
-
-  /** Adds a mutation to remove content length metadata value. */
-  public static void removeContentLength(ContentMetadataMutations mutations) {
-    mutations.remove(METADATA_NAME_CONTENT_LENGTH);
-  }
-
-  /** Returns the redirected uri metadata, or {@code null} if not set. */
-  public @Nullable static Uri getRedirectedUri(ContentMetadata contentMetadata) {
-    String redirectedUri = contentMetadata.get(METADATA_NAME_REDIRECTED_URI, (String) null);
-    return redirectedUri == null ? null : Uri.parse(redirectedUri);
-  }
-
-  /**
-   * Adds a mutation to set redirected uri metadata value. Passing {@code null} as {@code uri} isn't
-   * allowed.
-   */
-  public static void setRedirectedUri(ContentMetadataMutations mutations, Uri uri) {
-    mutations.set(METADATA_NAME_REDIRECTED_URI, uri.toString());
-  }
-
-  /** Adds a mutation to remove redirected uri metadata value. */
-  public static void removeRedirectedUri(ContentMetadataMutations mutations) {
-    mutations.remove(METADATA_NAME_REDIRECTED_URI);
-  }
-
-  private ContentMetadataInternal() {
-    // Prevent instantiation.
-  }
-}

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/ContentMetadataMutations.java

@@ -15,6 +15,9 @@
  */
 package com.google.android.exoplayer2.upstream.cache;
 
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -30,6 +33,36 @@ import java.util.Map.Entry;
  */
 public class ContentMetadataMutations {
 
+  /**
+   * Adds a mutation to set the {@link ContentMetadata#KEY_CONTENT_LENGTH} value, or to remove any
+   * existing value if {@link C#LENGTH_UNSET} is passed.
+   *
+   * @param mutations The mutations to modify.
+   * @param length The length value, or {@link C#LENGTH_UNSET} to remove any existing entry.
+   * @return The mutations instance, for convenience.
+   */
+  public static ContentMetadataMutations setContentLength(
+      ContentMetadataMutations mutations, long length) {
+    return mutations.set(ContentMetadata.KEY_CONTENT_LENGTH, length);
+  }
+
+  /**
+   * Adds a mutation to set the {@link ContentMetadata#KEY_REDIRECTED_URI} value, or to remove any
+   * existing entry if {@code null} is passed.
+   *
+   * @param mutations The mutations to modify.
+   * @param uri The {@link Uri} value, or {@code null} to remove any existing entry.
+   * @return The mutations instance, for convenience.
+   */
+  public static ContentMetadataMutations setRedirectedUri(
+      ContentMetadataMutations mutations, @Nullable Uri uri) {
+    if (uri == null) {
+      return mutations.remove(ContentMetadata.KEY_REDIRECTED_URI);
+    } else {
+      return mutations.set(ContentMetadata.KEY_REDIRECTED_URI, uri.toString());
+    }
+  }
+
   private final Map<String, Object> editedValues;
   private final List<String> removedValues;
 
@@ -45,7 +78,7 @@ public class ContentMetadataMutations {
    *
    * @param name The name of the metadata value.
    * @param value The value to be set.
-   * @return This Editor instance, for convenience.
+   * @return This instance, for convenience.
    */
   public ContentMetadataMutations set(String name, String value) {
     return checkAndSet(name, value);
@@ -56,7 +89,7 @@ public class ContentMetadataMutations {
    *
    * @param name The name of the metadata value.
    * @param value The value to be set.
-   * @return This Editor instance, for convenience.
+   * @return This instance, for convenience.
    */
   public ContentMetadataMutations set(String name, long value) {
     return checkAndSet(name, value);
@@ -68,7 +101,7 @@ public class ContentMetadataMutations {
    *
    * @param name The name of the metadata value.
    * @param value The value to be set.
-   * @return This Editor instance, for convenience.
+   * @return This instance, for convenience.
    */
   public ContentMetadataMutations set(String name, byte[] value) {
     return checkAndSet(name, Arrays.copyOf(value, value.length));
@@ -78,7 +111,7 @@ public class ContentMetadataMutations {
    * Adds a mutation to remove a metadata value.
    *
    * @param name The name of the metadata value.
-   * @return This Editor instance, for convenience.
+   * @return This instance, for convenience.
    */
   public ContentMetadataMutations remove(String name) {
     removedValues.add(name);

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/DefaultContentMetadata.java

@@ -64,6 +64,10 @@ public final class DefaultContentMetadata implements ContentMetadata {
 
   private final Map<String, byte[]> metadata;
 
+  public DefaultContentMetadata() {
+    this(Collections.emptyMap());
+  }
+
   private DefaultContentMetadata(Map<String, byte[]> metadata) {
     this.metadata = Collections.unmodifiableMap(metadata);
   }
@@ -74,7 +78,7 @@ public final class DefaultContentMetadata implements ContentMetadata {
    */
   public DefaultContentMetadata copyWithMutationsApplied(ContentMetadataMutations mutations) {
     Map<String, byte[]> mutatedMetadata = applyMutations(metadata, mutations);
-    if (isMetadataEqual(mutatedMetadata)) {
+    if (isMetadataEqual(metadata, mutatedMetadata)) {
       return this;
     }
     return new DefaultContentMetadata(mutatedMetadata);
@@ -97,7 +101,8 @@ public final class DefaultContentMetadata implements ContentMetadata {
   }
 
   @Override
-  public final byte[] get(String name, byte[] defaultValue) {
+  @Nullable
+  public final byte[] get(String name, @Nullable byte[] defaultValue) {
     if (metadata.containsKey(name)) {
       byte[] bytes = metadata.get(name);
       return Arrays.copyOf(bytes, bytes.length);
@@ -107,7 +112,8 @@ public final class DefaultContentMetadata implements ContentMetadata {
   }
 
   @Override
-  public final String get(String name, String defaultValue) {
+  @Nullable
+  public final String get(String name, @Nullable String defaultValue) {
     if (metadata.containsKey(name)) {
       byte[] bytes = metadata.get(name);
       return new String(bytes, Charset.forName(C.UTF8_NAME));
@@ -139,21 +145,7 @@ public final class DefaultContentMetadata implements ContentMetadata {
     if (o == null || getClass() != o.getClass()) {
       return false;
     }
-    return isMetadataEqual(((DefaultContentMetadata) o).metadata);
-  }
-
-  private boolean isMetadataEqual(Map<String, byte[]> otherMetadata) {
-    if (metadata.size() != otherMetadata.size()) {
-      return false;
-    }
-    for (Entry<String, byte[]> entry : metadata.entrySet()) {
-      byte[] value = entry.getValue();
-      byte[] otherValue = otherMetadata.get(entry.getKey());
-      if (!Arrays.equals(value, otherValue)) {
-        return false;
-      }
-    }
-    return true;
+    return isMetadataEqual(metadata, ((DefaultContentMetadata) o).metadata);
   }
 
   @Override
@@ -168,6 +160,20 @@ public final class DefaultContentMetadata implements ContentMetadata {
     return hashCode;
   }
 
+  private static boolean isMetadataEqual(Map<String, byte[]> first, Map<String, byte[]> second) {
+    if (first.size() != second.size()) {
+      return false;
+    }
+    for (Entry<String, byte[]> entry : first.entrySet()) {
+      byte[] value = entry.getValue();
+      byte[] otherValue = second.get(entry.getKey());
+      if (!Arrays.equals(value, otherValue)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
   private static Map<String, byte[]> applyMutations(
       Map<String, byte[]> otherMetadata, ContentMetadataMutations mutations) {
     HashMap<String, byte[]> metadata = new HashMap<>(otherMetadata);

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/SimpleCache.java

@@ -146,13 +146,16 @@ public final class SimpleCache implements Cache {
   }
 
   @Override
-  public synchronized void release() throws CacheException {
+  public synchronized void release() {
     if (released) {
       return;
     }
     listeners.clear();
+    removeStaleSpans();
     try {
-      removeStaleSpansAndCachedContents();
+      index.store();
+    } catch (CacheException e) {
+      Log.e(TAG, "Storing index file failed", e);
     } finally {
       unlockFolder(cacheDir);
       released = true;
@@ -265,7 +268,7 @@ public final class SimpleCache implements Cache {
     if (!cacheDir.exists()) {
       // For some reason the cache directory doesn't exist. Make a best effort to create it.
       cacheDir.mkdirs();
-      removeStaleSpansAndCachedContents();
+      removeStaleSpans();
     }
     evictor.onStartFile(this, key, position, maxLength);
     return SimpleCacheSpan.getCacheFile(
@@ -290,7 +293,7 @@ public final class SimpleCache implements Cache {
       return;
     }
     // Check if the span conflicts with the set content length
-    long length = ContentMetadataInternal.getContentLength(cachedContent.getMetadata());
+    long length = ContentMetadata.getContentLength(cachedContent.getMetadata());
     if (length != C.LENGTH_UNSET) {
       Assertions.checkState((span.position + span.length) <= length);
     }
@@ -311,9 +314,9 @@ public final class SimpleCache implements Cache {
   }
 
   @Override
-  public synchronized void removeSpan(CacheSpan span) throws CacheException {
+  public synchronized void removeSpan(CacheSpan span) {
     Assertions.checkState(!released);
-    removeSpan(span, true);
+    removeSpanInternal(span);
   }
 
   @Override
@@ -330,18 +333,6 @@ public final class SimpleCache implements Cache {
     return cachedContent != null ? cachedContent.getCachedBytesLength(position, length) : -length;
   }
 
-  @Override
-  public synchronized void setContentLength(String key, long length) throws CacheException {
-    ContentMetadataMutations mutations = new ContentMetadataMutations();
-    ContentMetadataInternal.setContentLength(mutations, length);
-    applyContentMetadataMutations(key, mutations);
-  }
-
-  @Override
-  public synchronized long getContentLength(String key) {
-    return ContentMetadataInternal.getContentLength(getContentMetadata(key));
-  }
-
   @Override
   public synchronized void applyContentMetadataMutations(
       String key, ContentMetadataMutations mutations) throws CacheException {
@@ -379,7 +370,7 @@ public final class SimpleCache implements Cache {
       if (span.isCached && !span.file.exists()) {
         // The file has been deleted from under us. It's likely that other files will have been
         // deleted too, so scan the whole in-memory representation.
-        removeStaleSpansAndCachedContents();
+        removeStaleSpans();
         continue;
       }
       return span;
@@ -431,27 +422,21 @@ public final class SimpleCache implements Cache {
     notifySpanAdded(span);
   }
 
-  private void removeSpan(CacheSpan span, boolean removeEmptyCachedContent) throws CacheException {
+  private void removeSpanInternal(CacheSpan span) {
     CachedContent cachedContent = index.get(span.key);
     if (cachedContent == null || !cachedContent.removeSpan(span)) {
       return;
     }
     totalSpace -= span.length;
-    try {
-      if (removeEmptyCachedContent) {
-        index.maybeRemove(cachedContent.key);
-        index.store();
-      }
-    } finally {
-      notifySpanRemoved(span);
-    }
+    index.maybeRemove(cachedContent.key);
+    notifySpanRemoved(span);
   }
 
   /**
    * Scans all of the cached spans in the in-memory representation, removing any for which files no
    * longer exist.
    */
-  private void removeStaleSpansAndCachedContents() throws CacheException {
+  private void removeStaleSpans() {
     ArrayList<CacheSpan> spansToBeRemoved = new ArrayList<>();
     for (CachedContent cachedContent : index.getAll()) {
       for (CacheSpan span : cachedContent.getSpans()) {
@@ -461,11 +446,8 @@ public final class SimpleCache implements Cache {
       }
     }
     for (int i = 0; i < spansToBeRemoved.size(); i++) {
-      // Remove span but not CachedContent to prevent multiple index.store() calls.
-      removeSpan(spansToBeRemoved.get(i), false);
+      removeSpanInternal(spansToBeRemoved.get(i));
     }
-    index.removeEmpty();
-    index.store();
   }
 
   private void notifySpanRemoved(CacheSpan span) {

library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java

@@ -98,7 +98,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
   private final EventDispatcher eventDispatcher;
   private final long allowedJoiningTimeMs;
   private final int maxDroppedFramesToNotify;
-  private final boolean deviceNeedsAutoFrcWorkaround;
+  private final boolean deviceNeedsNoPostProcessWorkaround;
   private final long[] pendingOutputStreamOffsetsUs;
   private final long[] pendingOutputStreamSwitchTimesUs;
 
@@ -226,7 +226,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
     this.context = context.getApplicationContext();
     frameReleaseTimeHelper = new VideoFrameReleaseTimeHelper(this.context);
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
-    deviceNeedsAutoFrcWorkaround = deviceNeedsAutoFrcWorkaround();
+    deviceNeedsNoPostProcessWorkaround = deviceNeedsNoPostProcessWorkaround();
     pendingOutputStreamOffsetsUs = new long[MAX_PENDING_OUTPUT_STREAM_OFFSET_COUNT];
     pendingOutputStreamSwitchTimesUs = new long[MAX_PENDING_OUTPUT_STREAM_OFFSET_COUNT];
     outputStreamOffsetUs = C.TIME_UNSET;
@@ -484,7 +484,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
             format,
             codecMaxValues,
             codecOperatingRate,
-            deviceNeedsAutoFrcWorkaround,
+            deviceNeedsNoPostProcessWorkaround,
             tunnelingAudioSessionId);
     if (surface == null) {
       Assertions.checkState(shouldUseDummySurface(codecInfo));
@@ -1036,8 +1036,8 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
    * @param codecMaxValues Codec max values that should be used when configuring the decoder.
    * @param codecOperatingRate The codec operating rate, or {@link #CODEC_OPERATING_RATE_UNSET} if
    *     no codec operating rate should be set.
-   * @param deviceNeedsAutoFrcWorkaround Whether the device is known to enable frame-rate conversion
-   *     logic that negatively impacts ExoPlayer.
+   * @param deviceNeedsNoPostProcessWorkaround Whether the device is known to do post processing by
+   *     default that isn't compatible with ExoPlayer.
    * @param tunnelingAudioSessionId The audio session id to use for tunneling, or {@link
    *     C#AUDIO_SESSION_ID_UNSET} if tunneling should not be enabled.
    * @return The framework {@link MediaFormat} that should be used to configure the decoder.
@@ -1047,7 +1047,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
       Format format,
       CodecMaxValues codecMaxValues,
       float codecOperatingRate,
-      boolean deviceNeedsAutoFrcWorkaround,
+      boolean deviceNeedsNoPostProcessWorkaround,
       int tunnelingAudioSessionId) {
     MediaFormat mediaFormat = new MediaFormat();
     // Set format parameters that should always be set.
@@ -1071,7 +1071,8 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
         mediaFormat.setFloat(MediaFormat.KEY_OPERATING_RATE, codecOperatingRate);
       }
     }
-    if (deviceNeedsAutoFrcWorkaround) {
+    if (deviceNeedsNoPostProcessWorkaround) {
+      mediaFormat.setInteger("no-post-process", 1);
       mediaFormat.setInteger("auto-frc", 0);
     }
     if (tunnelingAudioSessionId != C.AUDIO_SESSION_ID_UNSET) {
@@ -1265,21 +1266,21 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
   }
 
   /**
-   * Returns whether the device is known to enable frame-rate conversion logic that negatively
-   * impacts ExoPlayer.
-   * <p>
-   * If true is returned then we explicitly disable the feature.
+   * Returns whether the device is known to do post processing by default that isn't compatible with
+   * ExoPlayer.
    *
-   * @return True if the device is known to enable frame-rate conversion logic that negatively
-   *     impacts ExoPlayer. False otherwise.
+   * @return Whether the device is known to do post processing by default that isn't compatible with
+   *     ExoPlayer.
    */
-  private static boolean deviceNeedsAutoFrcWorkaround() {
-    // nVidia Shield prior to M tries to adjust the playback rate to better map the frame-rate of
+  private static boolean deviceNeedsNoPostProcessWorkaround() {
+    // Nvidia devices prior to M try to adjust the playback rate to better map the frame-rate of
     // content to the refresh rate of the display. For example playback of 23.976fps content is
     // adjusted to play at 1.001x speed when the output display is 60Hz. Unfortunately the
     // implementation causes ExoPlayer's reported playback position to drift out of sync. Captions
-    // also lose sync [Internal: b/26453592].
-    return Util.SDK_INT <= 22 && "foster".equals(Util.DEVICE) && "NVIDIA".equals(Util.MANUFACTURER);
+    // also lose sync [Internal: b/26453592]. Even after M, the devices may apply post processing
+    // operations that can modify frame output timestamps, which is incompatible with ExoPlayer's
+    // logic for skipping decode-only frames.
+    return "NVIDIA".equals(Util.MANUFACTURER);
   }
 
   /*
@@ -1305,163 +1306,171 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
    *     incorrectly.
    */
   protected boolean codecNeedsSetOutputSurfaceWorkaround(String name) {
-    if (Util.SDK_INT >= 27 || name.startsWith("OMX.google")) {
-      // Devices running API level 27 or later should also be unaffected. Google OMX decoders are
-      // not known to have this issue on any API level.
+    if (name.startsWith("OMX.google")) {
+      // Google OMX decoders are not known to have this issue on any API level.
       return false;
     }
-    // Work around:
-    // https://github.com/google/ExoPlayer/issues/3236,
-    // https://github.com/google/ExoPlayer/issues/3355,
-    // https://github.com/google/ExoPlayer/issues/3439,
-    // https://github.com/google/ExoPlayer/issues/3724,
-    // https://github.com/google/ExoPlayer/issues/3835,
-    // https://github.com/google/ExoPlayer/issues/4006,
-    // https://github.com/google/ExoPlayer/issues/4084,
-    // https://github.com/google/ExoPlayer/issues/4104,
-    // https://github.com/google/ExoPlayer/issues/4134,
-    // https://github.com/google/ExoPlayer/issues/4315,
-    // https://github.com/google/ExoPlayer/issues/4419,
-    // https://github.com/google/ExoPlayer/issues/4460,
-    // https://github.com/google/ExoPlayer/issues/4468.
     synchronized (MediaCodecVideoRenderer.class) {
       if (!evaluatedDeviceNeedsSetOutputSurfaceWorkaround) {
-        switch (Util.DEVICE) {
-          case "1601":
-          case "1713":
-          case "1714":
-          case "A10-70F":
-          case "A1601":
-          case "A2016a40":
-          case "A7000-a":
-          case "A7000plus":
-          case "A7010a48":
-          case "A7020a48":
-          case "AquaPowerM":
-          case "ASUS_X00AD_2":
-          case "Aura_Note_2":
-          case "BLACK-1X":
-          case "BRAVIA_ATV2":
-          case "C1":
-          case "ComioS1":
-          case "CP8676_I02":
-          case "CPH1609":
-          case "CPY83_I00":
-          case "cv1":
-          case "cv3":
-          case "deb":
-          case "E5643":
-          case "ELUGA_A3_Pro":
-          case "ELUGA_Note":
-          case "ELUGA_Prim":
-          case "ELUGA_Ray_X":
-          case "EverStar_S":
-          case "F3111":
-          case "F3113":
-          case "F3116":
-          case "F3211":
-          case "F3213":
-          case "F3215":
-          case "F3311":
-          case "flo":
-          case "GiONEE_CBL7513":
-          case "GiONEE_GBL7319":
-          case "GIONEE_GBL7360":
-          case "GIONEE_SWW1609":
-          case "GIONEE_SWW1627":
-          case "GIONEE_SWW1631":
-          case "GIONEE_WBL5708":
-          case "GIONEE_WBL7365":
-          case "GIONEE_WBL7519":
-          case "griffin":
-          case "htc_e56ml_dtul":
-          case "hwALE-H":
-          case "HWBLN-H":
-          case "HWCAM-H":
-          case "HWVNS-H":
-          case "i9031":
-          case "iball8735_9806":
-          case "Infinix-X572":
-          case "iris60":
-          case "itel_S41":
-          case "j2xlteins":
-          case "JGZ":
-          case "K50a40":
-          case "kate":
-          case "le_x6":
-          case "LS-5017":
-          case "M5c":
-          case "manning":
-          case "marino_f":
-          case "MEIZU_M5":
-          case "mh":
-          case "mido":
-          case "MX6":
-          case "namath":
-          case "nicklaus_f":
-          case "NX541J":
-          case "NX573J":
-          case "OnePlus5T":
-          case "p212":
-          case "P681":
-          case "P85":
-          case "panell_d":
-          case "panell_dl":
-          case "panell_ds":
-          case "panell_dt":
-          case "PB2-670M":
-          case "PGN528":
-          case "PGN610":
-          case "PGN611":
-          case "Phantom6":
-          case "Pixi4-7_3G":
-          case "Pixi5-10_4G":
-          case "PLE":
-          case "PRO7S":
-          case "Q350":
-          case "Q4260":
-          case "Q427":
-          case "Q4310":
-          case "Q5":
-          case "QM16XE_U":
-          case "QX1":
-          case "santoni":
-          case "Slate_Pro":
-          case "SVP-DTV15":
-          case "s905x018":
-          case "taido_row":
-          case "TB3-730F":
-          case "TB3-730X":
-          case "TB3-850F":
-          case "TB3-850M":
-          case "tcl_eu":
-          case "V1":
-          case "V23GB":
-          case "V5":
-          case "vernee_M5":
-          case "watson":
-          case "whyred":
-          case "woods_f":
-          case "woods_fn":
-          case "X3_HK":
-          case "XE2X":
-          case "XT1663":
-          case "Z12_PRO":
-          case "Z80":
-            deviceNeedsSetOutputSurfaceWorkaround = true;
-            break;
-          default:
-            // Do nothing.
-            break;
-        }
-        switch (Util.MODEL) {
-          case "AFTA":
-          case "AFTN":
-            deviceNeedsSetOutputSurfaceWorkaround = true;
-            break;
-          default:
-            // Do nothing.
-            break;
+        if (Util.SDK_INT <= 27 && "dangal".equals(Util.DEVICE)) {
+          // Dangal is affected on API level 27: https://github.com/google/ExoPlayer/issues/5169.
+          deviceNeedsSetOutputSurfaceWorkaround = true;
+        } else if (Util.SDK_INT >= 27) {
+          // In general, devices running API level 27 or later should be unaffected. Do nothing.
+        } else {
+          // Enable the workaround on a per-device basis. Works around:
+          // https://github.com/google/ExoPlayer/issues/3236,
+          // https://github.com/google/ExoPlayer/issues/3355,
+          // https://github.com/google/ExoPlayer/issues/3439,
+          // https://github.com/google/ExoPlayer/issues/3724,
+          // https://github.com/google/ExoPlayer/issues/3835,
+          // https://github.com/google/ExoPlayer/issues/4006,
+          // https://github.com/google/ExoPlayer/issues/4084,
+          // https://github.com/google/ExoPlayer/issues/4104,
+          // https://github.com/google/ExoPlayer/issues/4134,
+          // https://github.com/google/ExoPlayer/issues/4315,
+          // https://github.com/google/ExoPlayer/issues/4419,
+          // https://github.com/google/ExoPlayer/issues/4460,
+          // https://github.com/google/ExoPlayer/issues/4468.
+          switch (Util.DEVICE) {
+            case "1601":
+            case "1713":
+            case "1714":
+            case "A10-70F":
+            case "A1601":
+            case "A2016a40":
+            case "A7000-a":
+            case "A7000plus":
+            case "A7010a48":
+            case "A7020a48":
+            case "AquaPowerM":
+            case "ASUS_X00AD_2":
+            case "Aura_Note_2":
+            case "BLACK-1X":
+            case "BRAVIA_ATV2":
+            case "BRAVIA_ATV3_4K":
+            case "C1":
+            case "ComioS1":
+            case "CP8676_I02":
+            case "CPH1609":
+            case "CPY83_I00":
+            case "cv1":
+            case "cv3":
+            case "deb":
+            case "E5643":
+            case "ELUGA_A3_Pro":
+            case "ELUGA_Note":
+            case "ELUGA_Prim":
+            case "ELUGA_Ray_X":
+            case "EverStar_S":
+            case "F3111":
+            case "F3113":
+            case "F3116":
+            case "F3211":
+            case "F3213":
+            case "F3215":
+            case "F3311":
+            case "flo":
+            case "fugu":
+            case "GiONEE_CBL7513":
+            case "GiONEE_GBL7319":
+            case "GIONEE_GBL7360":
+            case "GIONEE_SWW1609":
+            case "GIONEE_SWW1627":
+            case "GIONEE_SWW1631":
+            case "GIONEE_WBL5708":
+            case "GIONEE_WBL7365":
+            case "GIONEE_WBL7519":
+            case "griffin":
+            case "htc_e56ml_dtul":
+            case "hwALE-H":
+            case "HWBLN-H":
+            case "HWCAM-H":
+            case "HWVNS-H":
+            case "i9031":
+            case "iball8735_9806":
+            case "Infinix-X572":
+            case "iris60":
+            case "itel_S41":
+            case "j2xlteins":
+            case "JGZ":
+            case "K50a40":
+            case "kate":
+            case "le_x6":
+            case "LS-5017":
+            case "M5c":
+            case "manning":
+            case "marino_f":
+            case "MEIZU_M5":
+            case "mh":
+            case "mido":
+            case "MX6":
+            case "namath":
+            case "nicklaus_f":
+            case "NX541J":
+            case "NX573J":
+            case "OnePlus5T":
+            case "p212":
+            case "P681":
+            case "P85":
+            case "panell_d":
+            case "panell_dl":
+            case "panell_ds":
+            case "panell_dt":
+            case "PB2-670M":
+            case "PGN528":
+            case "PGN610":
+            case "PGN611":
+            case "Phantom6":
+            case "Pixi4-7_3G":
+            case "Pixi5-10_4G":
+            case "PLE":
+            case "PRO7S":
+            case "Q350":
+            case "Q4260":
+            case "Q427":
+            case "Q4310":
+            case "Q5":
+            case "QM16XE_U":
+            case "QX1":
+            case "santoni":
+            case "Slate_Pro":
+            case "SVP-DTV15":
+            case "s905x018":
+            case "taido_row":
+            case "TB3-730F":
+            case "TB3-730X":
+            case "TB3-850F":
+            case "TB3-850M":
+            case "tcl_eu":
+            case "V1":
+            case "V23GB":
+            case "V5":
+            case "vernee_M5":
+            case "watson":
+            case "whyred":
+            case "woods_f":
+            case "woods_fn":
+            case "X3_HK":
+            case "XE2X":
+            case "XT1663":
+            case "Z12_PRO":
+            case "Z80":
+              deviceNeedsSetOutputSurfaceWorkaround = true;
+              break;
+            default:
+              // Do nothing.
+              break;
+          }
+          switch (Util.MODEL) {
+            case "AFTA":
+            case "AFTN":
+              deviceNeedsSetOutputSurfaceWorkaround = true;
+              break;
+            default:
+              // Do nothing.
+              break;
+          }
         }
         evaluatedDeviceNeedsSetOutputSurfaceWorkaround = true;
       }

library/core/src/test/assets/ttml/bitmap_percentage_region.xml

@@ -0,0 +1,26 @@
+<tt xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata" xmlns:tts="http://www.w3.org/ns/ttml#styling" xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt" xml:lang="eng">
+    <head>
+        <metadata>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_0">
+                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
+            </smpte:image>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_1">
+                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
+            </smpte:image>
+        </metadata>
+        <styling>
+            <style/>
+        </styling>
+        <layout>
+            <region xml:id="region_0" tts:extent="51% 12%" tts:origin="24% 78%"/>
+            <region xml:id="region_1" tts:extent="57% 6%" tts:origin="21% 85%"/>
+            <region xml:id="region_2" tts:extent="51% 12%" tts:origin="24% 28%"/>
+            <region xml:id="region_3" tts:extent="57% 6%" tts:origin="21% 35%"/>
+        </layout>
+    </head>
+    <body>
+        <div begin="00:00:00.200" end="00:00:03.000" region="region_2" smpte:backgroundImage="#img_0"/>
+        <div begin="00:00:03.200" end="00:00:06.937" region="region_3" smpte:backgroundImage="#img_1"/>
+        <div begin="00:00:07.200" end="00:59:03.000" region="region_2" smpte:backgroundImage="#img_0"/>
+    </body>
+</tt>

library/core/src/test/assets/ttml/bitmap_pixel_region.xml

@@ -0,0 +1,23 @@
+<tt xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata" xmlns:tts="http://www.w3.org/ns/ttml#styling" xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt" xml:lang="eng" tts:extent="1280px 720px">
+    <head>
+        <metadata>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_0">
+                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
+            </smpte:image>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_1">
+                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
+            </smpte:image>
+        </metadata>
+        <styling>
+            <style/>
+        </styling>
+        <layout>
+            <region xml:id="region_0" tts:extent="653px 86px" tts:origin="307px 562px"/>
+            <region xml:id="region_1" tts:extent="730px 43px" tts:origin="269px 612px"/>
+        </layout>
+    </head>
+    <body>
+        <div begin="00:00:00.200" end="00:00:03.000" region="region_0" smpte:backgroundImage="#img_0"/>
+        <div begin="00:00:03.200" end="00:00:06.937" region="region_1" smpte:backgroundImage="#img_1"/>
+    </body>
+</tt>

library/core/src/test/assets/ttml/bitmap_unsupported_region.xml

@@ -0,0 +1,23 @@
+<tt xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata" xmlns:tts="http://www.w3.org/ns/ttml#styling" xmlns:smpte="http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt" xml:lang="eng">
+    <head>
+        <metadata>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_0">
+                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
+            </smpte:image>
+            <smpte:image imagetype="PNG" encoding="Base64" xml:id="img_1">
+                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
+            </smpte:image>
+        </metadata>
+        <styling>
+            <style/>
+        </styling>
+        <layout>
+            <region xml:id="region_0" tts:extent="653px 86px" tts:origin="307px 562px"/>
+            <region xml:id="region_1" tts:extent="730px 43px" tts:origin="269px 612px"/>
+        </layout>
+    </head>
+    <body>
+        <div begin="00:00:00.200" end="00:00:03.000" region="region_0" smpte:backgroundImage="#img_0"/>
+        <div begin="00:00:03.200" end="00:00:06.937" region="region_1" smpte:backgroundImage="#img_1"/>
+    </body>
+</tt>

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadActionUtilTest.java

@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.offline;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.fail;
+
+import android.net.Uri;
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link DownloadActionUtil} class. */
+@RunWith(RobolectricTestRunner.class)
+public class DownloadActionUtilTest {
+  private Uri uri1;
+  private Uri uri2;
+
+  @Before
+  public void setUp() throws Exception {
+    uri1 = Uri.parse("http://abc.com/media1");
+    uri2 = Uri.parse("http://abc.com/media2");
+  }
+
+  @Test
+  public void mergeActions_ifQueueEmpty_throwsException() {
+    try {
+      DownloadActionUtil.mergeActions(toActionQueue());
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeActions_ifOneActionInQueue_returnsTheSameAction() {
+    DownloadAction action = createDownloadAction(uri1);
+
+    assertThat(DownloadActionUtil.mergeActions(toActionQueue(action))).isEqualTo(action);
+  }
+
+  @Test
+  public void mergeActions_ifActionsHaveDifferentType_throwsException() {
+    DownloadAction downloadAction1 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ null);
+    DownloadAction downloadAction2 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_DASH,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ null);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction1, downloadAction2);
+
+    try {
+      DownloadActionUtil.mergeActions(actionQueue);
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeActions_ifActionsHaveDifferentCacheKeys_throwsException() {
+    DownloadAction downloadAction1 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ "cacheKey1",
+            /* data= */ null);
+    DownloadAction downloadAction2 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ "cacheKey2",
+            /* data= */ null);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction1, downloadAction2);
+
+    try {
+      DownloadActionUtil.mergeActions(actionQueue);
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeActions_nullCacheKeyAndDifferentUrl_throwsException() {
+    DownloadAction downloadAction1 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ null);
+    DownloadAction downloadAction2 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri2,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ null);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction1, downloadAction2);
+
+    try {
+      DownloadActionUtil.mergeActions(actionQueue);
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeActions_sameCacheKeyAndDifferentUrl_latterUrlUsed() {
+    DownloadAction downloadAction1 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ "cacheKey1",
+            /* data= */ null);
+    DownloadAction downloadAction2 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri2,
+            Collections.emptyList(),
+            /* customCacheKey= */ "cacheKey1",
+            /* data= */ null);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction1, downloadAction2);
+
+    DownloadActionUtil.mergeActions(actionQueue);
+
+    DownloadAction mergedAction = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(mergedAction.uri).isEqualTo(uri2);
+  }
+
+  @Test
+  public void mergeActions_differentData_latterDataUsed() {
+    byte[] data1 = "data1".getBytes();
+    DownloadAction downloadAction1 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ data1);
+    byte[] data2 = "data2".getBytes();
+    DownloadAction downloadAction2 =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_PROGRESSIVE,
+            uri1,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ data2);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction1, downloadAction2);
+
+    DownloadActionUtil.mergeActions(actionQueue);
+
+    DownloadAction mergedAction = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(mergedAction.data).isEqualTo(data2);
+  }
+
+  @Test
+  public void mergeActions_ifRemoveActionLast_returnsRemoveAction() {
+    DownloadAction downloadAction = createDownloadAction(uri1);
+    DownloadAction removeAction = createRemoveAction(uri1);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(downloadAction, removeAction);
+
+    DownloadAction action = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(action).isEqualTo(removeAction);
+    assertThat(actionQueue).containsExactly(removeAction);
+  }
+
+  @Test
+  public void mergeActions_downloadActionAfterRemove_returnsRemoveKeepsDownload() {
+    DownloadAction removeAction = createRemoveAction(uri1);
+    DownloadAction downloadAction = createDownloadAction(uri1);
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(removeAction, downloadAction);
+
+    DownloadAction action = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(action).isEqualTo(removeAction);
+    assertThat(actionQueue).containsExactly(removeAction, downloadAction);
+  }
+
+  @Test
+  public void mergeActions_downloadActionsAfterRemove_returnsRemoveMergesDownloads() {
+    DownloadAction removeAction = createRemoveAction(uri1);
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    DownloadAction downloadAction1 =
+        createDownloadAction(uri1, Collections.singletonList(streamKey1));
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    DownloadAction downloadAction2 =
+        createDownloadAction(uri1, Collections.singletonList(streamKey2));
+    ArrayDeque<DownloadAction> actionQueue =
+        toActionQueue(removeAction, downloadAction1, downloadAction2);
+    DownloadAction mergedDownloadAction =
+        createDownloadAction(uri1, Arrays.asList(streamKey1, streamKey2));
+
+    DownloadAction action = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(action).isEqualTo(removeAction);
+    assertThat(actionQueue).containsExactly(removeAction, mergedDownloadAction);
+  }
+
+  @Test
+  public void mergeActions_actionBeforeRemove_ignoresActionBeforeRemove() {
+    DownloadAction removeAction = createRemoveAction(uri1);
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    DownloadAction downloadAction1 =
+        createDownloadAction(uri1, Collections.singletonList(streamKey1));
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    DownloadAction downloadAction2 =
+        createDownloadAction(uri1, Collections.singletonList(streamKey2));
+    StreamKey streamKey3 = new StreamKey(/* groupIndex= */ 2, /* trackIndex= */ 2);
+    DownloadAction downloadAction3 =
+        createDownloadAction(uri1, Collections.singletonList(streamKey3));
+    ArrayDeque<DownloadAction> actionQueue =
+        toActionQueue(downloadAction1, removeAction, downloadAction2, downloadAction3);
+    DownloadAction mergedDownloadAction =
+        createDownloadAction(uri1, Arrays.asList(streamKey2, streamKey3));
+
+    DownloadAction action = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(action).isEqualTo(removeAction);
+    assertThat(actionQueue).containsExactly(removeAction, mergedDownloadAction);
+  }
+
+  @Test
+  public void mergeActions_returnsMergedAction() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2};
+    StreamKey[] expectedKeys = new StreamKey[] {streamKey1, streamKey2};
+
+    doTestMergeActionsReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeActions_returnsUniqueKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey1Copy = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2, streamKey1Copy};
+    StreamKey[] expectedKeys = new StreamKey[] {streamKey1, streamKey2};
+
+    doTestMergeActionsReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeActions_ifFirstActionKeysEmpty_returnsEmptyKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2, streamKey1};
+    StreamKey[] expectedKeys = new StreamKey[] {};
+
+    doTestMergeActionsReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeActions_ifNotFirstActionKeysEmpty_returnsEmptyKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey2, streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {};
+    StreamKey[] expectedKeys = new StreamKey[] {};
+
+    doTestMergeActionsReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  private void doTestMergeActionsReturnsMergedKeys(
+      StreamKey[] keys1, StreamKey[] keys2, StreamKey[] expectedKeys) {
+    DownloadAction action1 = createDownloadAction(uri1, Arrays.asList(keys1));
+    DownloadAction action2 = createDownloadAction(uri1, Arrays.asList(keys2));
+    ArrayDeque<DownloadAction> actionQueue = toActionQueue(action1, action2);
+
+    DownloadAction mergedAction = DownloadActionUtil.mergeActions(actionQueue);
+
+    assertThat(mergedAction.type).isEqualTo(action1.type);
+    assertThat(mergedAction.uri).isEqualTo(action1.uri);
+    assertThat(mergedAction.customCacheKey).isEqualTo(action1.customCacheKey);
+    assertThat(mergedAction.isRemoveAction).isEqualTo(action1.isRemoveAction);
+    assertThat(mergedAction.keys).containsExactly((Object[]) expectedKeys);
+    assertThat(actionQueue).containsExactly(mergedAction);
+  }
+
+  private ArrayDeque<DownloadAction> toActionQueue(DownloadAction... actions) {
+    return new ArrayDeque<>(Arrays.asList(actions));
+  }
+
+  private static DownloadAction createDownloadAction(Uri uri) {
+    return createDownloadAction(uri, Collections.emptyList());
+  }
+
+  private static DownloadAction createDownloadAction(Uri uri, List<StreamKey> keys) {
+    return DownloadAction.createDownloadAction(
+        DownloadAction.TYPE_PROGRESSIVE, uri, keys, /* customCacheKey= */ null, /* data= */ null);
+  }
+
+  private static DownloadAction createRemoveAction(Uri uri) {
+    return DownloadAction.createRemoveAction(
+        DownloadAction.TYPE_PROGRESSIVE, uri, /* customCacheKey= */ null);
+  }
+}

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadHelperTest.java

@@ -0,0 +1,445 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.offline;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.net.Uri;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.Renderer;
+import com.google.android.exoplayer2.RenderersFactory;
+import com.google.android.exoplayer2.offline.DownloadHelper.Callback;
+import com.google.android.exoplayer2.source.TrackGroup;
+import com.google.android.exoplayer2.source.TrackGroupArray;
+import com.google.android.exoplayer2.testutil.FakeRenderer;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector.ParametersBuilder;
+import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
+import com.google.android.exoplayer2.trackselection.TrackSelection;
+import com.google.android.exoplayer2.util.ConditionVariable;
+import com.google.android.exoplayer2.util.MimeTypes;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadows.ShadowLooper;
+
+/** Unit tests for {@link DownloadHelper}. */
+@RunWith(RobolectricTestRunner.class)
+public class DownloadHelperTest {
+
+  private static final String TEST_DOWNLOAD_TYPE = "downloadType";
+  private static final String TEST_CACHE_KEY = "cacheKey";
+  private static final ManifestType TEST_MANIFEST = new ManifestType();
+
+  private static final Format VIDEO_FORMAT_LOW = createVideoFormat(/* bitrate= */ 200_000);
+  private static final Format VIDEO_FORMAT_HIGH = createVideoFormat(/* bitrate= */ 800_000);
+  private static final Format AUDIO_FORMAT_US = createAudioFormat(/* language= */ "US");
+  private static final Format AUDIO_FORMAT_ZH = createAudioFormat(/* language= */ "ZH");
+  private static final Format TEXT_FORMAT_US = createTextFormat(/* language= */ "US");
+  private static final Format TEXT_FORMAT_ZH = createTextFormat(/* language= */ "ZH");
+
+  private static final TrackGroup TRACK_GROUP_VIDEO_BOTH =
+      new TrackGroup(VIDEO_FORMAT_LOW, VIDEO_FORMAT_HIGH);
+  private static final TrackGroup TRACK_GROUP_VIDEO_SINGLE = new TrackGroup(VIDEO_FORMAT_LOW);
+  private static final TrackGroup TRACK_GROUP_AUDIO_US = new TrackGroup(AUDIO_FORMAT_US);
+  private static final TrackGroup TRACK_GROUP_AUDIO_ZH = new TrackGroup(AUDIO_FORMAT_ZH);
+  private static final TrackGroup TRACK_GROUP_TEXT_US = new TrackGroup(TEXT_FORMAT_US);
+  private static final TrackGroup TRACK_GROUP_TEXT_ZH = new TrackGroup(TEXT_FORMAT_ZH);
+  private static final TrackGroupArray TRACK_GROUP_ARRAY_ALL =
+      new TrackGroupArray(
+          TRACK_GROUP_VIDEO_BOTH,
+          TRACK_GROUP_AUDIO_US,
+          TRACK_GROUP_AUDIO_ZH,
+          TRACK_GROUP_TEXT_US,
+          TRACK_GROUP_TEXT_ZH);
+  private static final TrackGroupArray TRACK_GROUP_ARRAY_SINGLE =
+      new TrackGroupArray(TRACK_GROUP_VIDEO_SINGLE, TRACK_GROUP_AUDIO_US);
+  private static final TrackGroupArray[] TRACK_GROUP_ARRAYS =
+      new TrackGroupArray[] {TRACK_GROUP_ARRAY_ALL, TRACK_GROUP_ARRAY_SINGLE};
+
+  private Uri testUri;
+
+  private FakeDownloadHelper downloadHelper;
+
+  @Before
+  public void setUp() {
+    testUri = Uri.parse("http://test.uri");
+
+    FakeRenderer videoRenderer = new FakeRenderer(VIDEO_FORMAT_LOW, VIDEO_FORMAT_HIGH);
+    FakeRenderer audioRenderer = new FakeRenderer(AUDIO_FORMAT_US, AUDIO_FORMAT_ZH);
+    FakeRenderer textRenderer = new FakeRenderer(TEXT_FORMAT_US, TEXT_FORMAT_ZH);
+    RenderersFactory renderersFactory =
+        (handler, videoListener, audioListener, metadata, text, drm) ->
+            new Renderer[] {textRenderer, audioRenderer, videoRenderer};
+
+    downloadHelper = new FakeDownloadHelper(testUri, renderersFactory);
+  }
+
+  @Test
+  public void getManifest_returnsManifest() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    ManifestType manifest = downloadHelper.getManifest();
+
+    assertThat(manifest).isEqualTo(TEST_MANIFEST);
+  }
+
+  @Test
+  public void getPeriodCount_returnsPeriodCount() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    int periodCount = downloadHelper.getPeriodCount();
+
+    assertThat(periodCount).isEqualTo(2);
+  }
+
+  @Test
+  public void getTrackGroups_returnsTrackGroups() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    TrackGroupArray trackGroupArrayPeriod0 = downloadHelper.getTrackGroups(/* periodIndex= */ 0);
+    TrackGroupArray trackGroupArrayPeriod1 = downloadHelper.getTrackGroups(/* periodIndex= */ 1);
+
+    assertThat(trackGroupArrayPeriod0).isEqualTo(TRACK_GROUP_ARRAYS[0]);
+    assertThat(trackGroupArrayPeriod1).isEqualTo(TRACK_GROUP_ARRAYS[1]);
+  }
+
+  @Test
+  public void getMappedTrackInfo_returnsMappedTrackInfo() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    MappedTrackInfo mappedTracks0 = downloadHelper.getMappedTrackInfo(/* periodIndex= */ 0);
+    MappedTrackInfo mappedTracks1 = downloadHelper.getMappedTrackInfo(/* periodIndex= */ 1);
+
+    assertThat(mappedTracks0.getRendererCount()).isEqualTo(3);
+    assertThat(mappedTracks0.getRendererType(/* rendererIndex= */ 0)).isEqualTo(C.TRACK_TYPE_TEXT);
+    assertThat(mappedTracks0.getRendererType(/* rendererIndex= */ 1)).isEqualTo(C.TRACK_TYPE_AUDIO);
+    assertThat(mappedTracks0.getRendererType(/* rendererIndex= */ 2)).isEqualTo(C.TRACK_TYPE_VIDEO);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 0).length).isEqualTo(2);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 1).length).isEqualTo(2);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 2).length).isEqualTo(1);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 0).get(/* index= */ 0))
+        .isEqualTo(TRACK_GROUP_TEXT_US);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 0).get(/* index= */ 1))
+        .isEqualTo(TRACK_GROUP_TEXT_ZH);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 1).get(/* index= */ 0))
+        .isEqualTo(TRACK_GROUP_AUDIO_US);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 1).get(/* index= */ 1))
+        .isEqualTo(TRACK_GROUP_AUDIO_ZH);
+    assertThat(mappedTracks0.getTrackGroups(/* rendererIndex= */ 2).get(/* index= */ 0))
+        .isEqualTo(TRACK_GROUP_VIDEO_BOTH);
+
+    assertThat(mappedTracks1.getRendererCount()).isEqualTo(3);
+    assertThat(mappedTracks1.getRendererType(/* rendererIndex= */ 0)).isEqualTo(C.TRACK_TYPE_TEXT);
+    assertThat(mappedTracks1.getRendererType(/* rendererIndex= */ 1)).isEqualTo(C.TRACK_TYPE_AUDIO);
+    assertThat(mappedTracks1.getRendererType(/* rendererIndex= */ 2)).isEqualTo(C.TRACK_TYPE_VIDEO);
+    assertThat(mappedTracks1.getTrackGroups(/* rendererIndex= */ 0).length).isEqualTo(0);
+    assertThat(mappedTracks1.getTrackGroups(/* rendererIndex= */ 1).length).isEqualTo(1);
+    assertThat(mappedTracks1.getTrackGroups(/* rendererIndex= */ 2).length).isEqualTo(1);
+    assertThat(mappedTracks1.getTrackGroups(/* rendererIndex= */ 1).get(/* index= */ 0))
+        .isEqualTo(TRACK_GROUP_AUDIO_US);
+    assertThat(mappedTracks1.getTrackGroups(/* rendererIndex= */ 2).get(/* index= */ 0))
+        .isEqualTo(TRACK_GROUP_VIDEO_SINGLE);
+  }
+
+  @Test
+  public void getTrackSelections_returnsInitialSelection() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertSingleTrackSelectionEquals(selectedText0, TRACK_GROUP_TEXT_US, 0);
+    assertSingleTrackSelectionEquals(selectedAudio0, TRACK_GROUP_AUDIO_US, 0);
+    assertSingleTrackSelectionEquals(selectedVideo0, TRACK_GROUP_VIDEO_BOTH, 1);
+
+    assertThat(selectedText1).isEmpty();
+    assertSingleTrackSelectionEquals(selectedAudio1, TRACK_GROUP_AUDIO_US, 0);
+    assertSingleTrackSelectionEquals(selectedVideo1, TRACK_GROUP_VIDEO_SINGLE, 0);
+  }
+
+  @Test
+  public void getTrackSelections_afterClearTrackSelections_isEmpty() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+
+    // Clear only one period selection to verify second period selection is untouched.
+    downloadHelper.clearTrackSelections(/* periodIndex= */ 0);
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertThat(selectedText0).isEmpty();
+    assertThat(selectedAudio0).isEmpty();
+    assertThat(selectedVideo0).isEmpty();
+
+    // Verify
+    assertThat(selectedText1).isEmpty();
+    assertSingleTrackSelectionEquals(selectedAudio1, TRACK_GROUP_AUDIO_US, 0);
+    assertSingleTrackSelectionEquals(selectedVideo1, TRACK_GROUP_VIDEO_SINGLE, 0);
+  }
+
+  @Test
+  public void getTrackSelections_afterReplaceTrackSelections_returnsNewSelections()
+      throws Exception {
+    prepareDownloadHelper(downloadHelper);
+    DefaultTrackSelector.Parameters parameters =
+        new ParametersBuilder()
+            .setPreferredAudioLanguage("ZH")
+            .setPreferredTextLanguage("ZH")
+            .setRendererDisabled(/* rendererIndex= */ 2, true)
+            .build();
+
+    // Replace only one period selection to verify second period selection is untouched.
+    downloadHelper.replaceTrackSelections(/* periodIndex= */ 0, parameters);
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertSingleTrackSelectionEquals(selectedText0, TRACK_GROUP_TEXT_ZH, 0);
+    assertSingleTrackSelectionEquals(selectedAudio0, TRACK_GROUP_AUDIO_ZH, 0);
+    assertThat(selectedVideo0).isEmpty();
+
+    assertThat(selectedText1).isEmpty();
+    assertSingleTrackSelectionEquals(selectedAudio1, TRACK_GROUP_AUDIO_US, 0);
+    assertSingleTrackSelectionEquals(selectedVideo1, TRACK_GROUP_VIDEO_SINGLE, 0);
+  }
+
+  @Test
+  public void getTrackSelections_afterAddTrackSelections_returnsCombinedSelections()
+      throws Exception {
+    prepareDownloadHelper(downloadHelper);
+    // Select parameters to require some merging of track groups because the new parameters add
+    // all video tracks to initial video single track selection.
+    DefaultTrackSelector.Parameters parameters =
+        new ParametersBuilder()
+            .setPreferredAudioLanguage("ZH")
+            .setPreferredTextLanguage("US")
+            .build();
+
+    // Add only to one period selection to verify second period selection is untouched.
+    downloadHelper.addTrackSelection(/* periodIndex= */ 0, parameters);
+    List<TrackSelection> selectedText0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo0 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 0, /* rendererIndex= */ 2);
+    List<TrackSelection> selectedText1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 0);
+    List<TrackSelection> selectedAudio1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 1);
+    List<TrackSelection> selectedVideo1 =
+        downloadHelper.getTrackSelections(/* periodIndex= */ 1, /* rendererIndex= */ 2);
+
+    assertSingleTrackSelectionEquals(selectedText0, TRACK_GROUP_TEXT_US, 0);
+    assertThat(selectedAudio0).hasSize(2);
+    assertTrackSelectionEquals(selectedAudio0.get(0), TRACK_GROUP_AUDIO_US, 0);
+    assertTrackSelectionEquals(selectedAudio0.get(1), TRACK_GROUP_AUDIO_ZH, 0);
+    assertSingleTrackSelectionEquals(selectedVideo0, TRACK_GROUP_VIDEO_BOTH, 0, 1);
+
+    assertThat(selectedText1).isEmpty();
+    assertSingleTrackSelectionEquals(selectedAudio1, TRACK_GROUP_AUDIO_US, 0);
+    assertSingleTrackSelectionEquals(selectedVideo1, TRACK_GROUP_VIDEO_SINGLE, 0);
+  }
+
+  @Test
+  public void getDownloadAction_createsDownloadAction_withAllSelectedTracks() throws Exception {
+    prepareDownloadHelper(downloadHelper);
+    // Ensure we have track groups with multiple indices, renderers with multiple track groups and
+    // also renderers without any track groups.
+    DefaultTrackSelector.Parameters parameters =
+        new ParametersBuilder()
+            .setPreferredAudioLanguage("ZH")
+            .setPreferredTextLanguage("US")
+            .build();
+    downloadHelper.addTrackSelection(/* periodIndex= */ 0, parameters);
+    byte[] data = new byte[10];
+    Arrays.fill(data, (byte) 123);
+
+    DownloadAction downloadAction = downloadHelper.getDownloadAction(data);
+
+    assertThat(downloadAction.type).isEqualTo(TEST_DOWNLOAD_TYPE);
+    assertThat(downloadAction.uri).isEqualTo(testUri);
+    assertThat(downloadAction.customCacheKey).isEqualTo(TEST_CACHE_KEY);
+    assertThat(downloadAction.isRemoveAction).isFalse();
+    assertThat(downloadAction.data).isEqualTo(data);
+    assertThat(downloadAction.keys)
+        .containsExactly(
+            new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 0, /* trackIndex= */ 0),
+            new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 0, /* trackIndex= */ 1),
+            new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 1, /* trackIndex= */ 0),
+            new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 2, /* trackIndex= */ 0),
+            new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 3, /* trackIndex= */ 0),
+            new StreamKey(/* periodIndex= */ 1, /* groupIndex= */ 0, /* trackIndex= */ 0),
+            new StreamKey(/* periodIndex= */ 1, /* groupIndex= */ 1, /* trackIndex= */ 0));
+  }
+
+  @Test
+  public void getRemoveAction_returnsRemoveAction() {
+    DownloadAction removeAction = downloadHelper.getRemoveAction();
+
+    assertThat(removeAction.type).isEqualTo(TEST_DOWNLOAD_TYPE);
+    assertThat(removeAction.uri).isEqualTo(testUri);
+    assertThat(removeAction.customCacheKey).isEqualTo(TEST_CACHE_KEY);
+    assertThat(removeAction.isRemoveAction).isTrue();
+  }
+
+  private static void prepareDownloadHelper(FakeDownloadHelper downloadHelper) throws Exception {
+    AtomicReference<Exception> prepareException = new AtomicReference<>(null);
+    ConditionVariable preparedCondition = new ConditionVariable();
+    downloadHelper.prepare(
+        new Callback() {
+          @Override
+          public void onPrepared(DownloadHelper<?> helper) {
+            preparedCondition.open();
+          }
+
+          @Override
+          public void onPrepareError(DownloadHelper<?> helper, IOException e) {
+            prepareException.set(e);
+            preparedCondition.open();
+          }
+        });
+    while (!preparedCondition.block(0)) {
+      ShadowLooper.runMainLooperToNextTask();
+    }
+    if (prepareException.get() != null) {
+      throw prepareException.get();
+    }
+  }
+
+  private static Format createVideoFormat(int bitrate) {
+    return Format.createVideoSampleFormat(
+        /* id= */ null,
+        /* sampleMimeType= */ MimeTypes.VIDEO_H264,
+        /* codecs= */ null,
+        /* bitrate= */ bitrate,
+        /* maxInputSize= */ Format.NO_VALUE,
+        /* width= */ 480,
+        /* height= */ 360,
+        /* frameRate= */ Format.NO_VALUE,
+        /* initializationData= */ null,
+        /* drmInitData= */ null);
+  }
+
+  private static Format createAudioFormat(String language) {
+    return Format.createAudioSampleFormat(
+        /* id= */ null,
+        /* sampleMimeType= */ MimeTypes.AUDIO_AAC,
+        /* codecs= */ null,
+        /* bitrate= */ 48000,
+        /* maxInputSize= */ Format.NO_VALUE,
+        /* channelCount= */ 2,
+        /* sampleRate */ 44100,
+        /* initializationData= */ null,
+        /* drmInitData= */ null,
+        /* selectionFlags= */ C.SELECTION_FLAG_DEFAULT,
+        /* language= */ language);
+  }
+
+  private static Format createTextFormat(String language) {
+    return Format.createTextSampleFormat(
+        /* id= */ null,
+        /* sampleMimeType= */ MimeTypes.TEXT_VTT,
+        /* selectionFlags= */ C.SELECTION_FLAG_DEFAULT,
+        /* language= */ language);
+  }
+
+  private static void assertSingleTrackSelectionEquals(
+      List<TrackSelection> trackSelectionList, TrackGroup trackGroup, int... tracks) {
+    assertThat(trackSelectionList).hasSize(1);
+    assertTrackSelectionEquals(trackSelectionList.get(0), trackGroup, tracks);
+  }
+
+  private static void assertTrackSelectionEquals(
+      TrackSelection trackSelection, TrackGroup trackGroup, int... tracks) {
+    assertThat(trackSelection.getTrackGroup()).isEqualTo(trackGroup);
+    assertThat(trackSelection.length()).isEqualTo(tracks.length);
+    int[] selectedTracksInGroup = new int[trackSelection.length()];
+    for (int i = 0; i < trackSelection.length(); i++) {
+      selectedTracksInGroup[i] = trackSelection.getIndexInTrackGroup(i);
+    }
+    Arrays.sort(selectedTracksInGroup);
+    Arrays.sort(tracks);
+    assertThat(selectedTracksInGroup).isEqualTo(tracks);
+  }
+
+  private static final class ManifestType {}
+
+  private static final class FakeDownloadHelper extends DownloadHelper<ManifestType> {
+
+    public FakeDownloadHelper(Uri testUri, RenderersFactory renderersFactory) {
+      super(
+          TEST_DOWNLOAD_TYPE,
+          testUri,
+          TEST_CACHE_KEY,
+          DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS,
+          renderersFactory,
+          /* drmSessionManager= */ null);
+    }
+
+    @Override
+    protected ManifestType loadManifest(Uri uri) throws IOException {
+      return TEST_MANIFEST;
+    }
+
+    @Override
+    protected TrackGroupArray[] getTrackGroupArrays(ManifestType manifest) {
+      assertThat(manifest).isEqualTo(TEST_MANIFEST);
+      return TRACK_GROUP_ARRAYS;
+    }
+
+    @Override
+    protected StreamKey toStreamKey(
+        int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup) {
+      return new StreamKey(periodIndex, trackGroupIndex, trackIndexInTrackGroup);
+    }
+  }
+}

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadManagerTest.java

@@ -20,16 +20,17 @@ import static org.junit.Assert.fail;
 
 import android.net.Uri;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState.State;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState.State;
 import com.google.android.exoplayer2.testutil.DummyMainThread;
 import com.google.android.exoplayer2.testutil.RobolectricUtil;
 import com.google.android.exoplayer2.testutil.TestDownloadManagerListener;
 import com.google.android.exoplayer2.util.Util;
 import java.io.File;
 import java.io.IOException;
-import java.util.Collections;
-import java.util.IdentityHashMap;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import org.junit.After;
@@ -52,7 +53,9 @@ public class DownloadManagerTest {
   private static final int ASSERT_FALSE_TIME = 1000;
   /* Maximum retry delay in DownloadManager. */
   private static final int MAX_RETRY_DELAY = 5000;
-
+  /* Maximum number of times a downloader can be restarted before doing a released check. */
+  private static final int MAX_STARTS_BEFORE_RELEASED = 1;
+  /** The minimum number of times a task must be retried before failing. */
   private static final int MIN_RETRY_COUNT = 3;
 
   private Uri uri1;
@@ -84,309 +87,329 @@ public class DownloadManagerTest {
   }
 
   @Test
-  public void testDownloadActionRuns() throws Throwable {
-    doTestDownloaderRuns(createDownloadRunner(uri1));
+  public void downloadRunner_multipleInstancePerContent_throwsException() {
+    boolean exceptionThrown = false;
+    try {
+      new DownloadRunner(uri1);
+      new DownloadRunner(uri1);
+      // can't put fail() here as it would be caught in the catch below.
+    } catch (Throwable e) {
+      exceptionThrown = true;
+    }
+    assertThat(exceptionThrown).isTrue();
   }
 
   @Test
-  public void testRemoveActionRuns() throws Throwable {
-    doTestDownloaderRuns(createRemoveRunner(uri1));
+  public void downloadRunner_handleActionReturnsDifferentTaskId_throwsException() {
+    DownloadRunner runner = new DownloadRunner(uri1).postDownloadAction();
+    TaskWrapper task = runner.getTask();
+    runner.setTask(new TaskWrapper(task.taskId + 10000));
+    boolean exceptionThrown = false;
+    try {
+      runner.postDownloadAction();
+      // can't put fail() here as it would be caught in the catch below.
+    } catch (Throwable e) {
+      exceptionThrown = true;
+    }
+    assertThat(exceptionThrown).isTrue();
   }
 
   @Test
-  public void testDownloadRetriesThenFails() throws Throwable {
-    DownloadRunner downloadRunner = createDownloadRunner(uri1);
-    downloadRunner.postAction();
-    FakeDownloader fakeDownloader = downloadRunner.downloader;
-    fakeDownloader.enableDownloadIOException = true;
+  public void multipleActionsForTheSameContent_executedOnTheSameTask() {
+    // Two download actions on first task
+    new DownloadRunner(uri1).postDownloadAction().postDownloadAction();
+    // One download, one remove actions on second task
+    new DownloadRunner(uri2).postDownloadAction().postRemoveAction();
+    // Two remove actions on third task
+    new DownloadRunner(uri3).postRemoveAction().postRemoveAction();
+  }
+
+  @Test
+  public void actionsForDifferentContent_executedOnDifferentTasks() {
+    TaskWrapper task1 = new DownloadRunner(uri1).postDownloadAction().getTask();
+    TaskWrapper task2 = new DownloadRunner(uri2).postDownloadAction().getTask();
+    TaskWrapper task3 = new DownloadRunner(uri3).postRemoveAction().getTask();
+
+    assertThat(task1).isNoneOf(task2, task3);
+    assertThat(task2).isNotEqualTo(task3);
+  }
+
+  @Test
+  public void postDownloadAction_downloads() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    TaskWrapper task = runner.postDownloadAction().getTask();
+    task.assertStarted();
+    runner.getDownloader(0).unblock().assertReleased().assertStartCount(1);
+    task.assertCompleted();
+    runner.assertCreatedDownloaderCount(1);
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void postRemoveAction_removes() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    TaskWrapper task = runner.postRemoveAction().getTask();
+    task.assertStarted();
+    runner.getDownloader(0).unblock().assertReleased().assertStartCount(1);
+    task.assertCompleted();
+    runner.assertCreatedDownloaderCount(1);
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void downloadFails_retriesThenTaskFails() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    runner.postDownloadAction();
+    FakeDownloader downloader = runner.getDownloader(0);
+
     for (int i = 0; i <= MIN_RETRY_COUNT; i++) {
-      fakeDownloader.assertStarted(MAX_RETRY_DELAY).unblock();
+      downloader.assertStarted(MAX_RETRY_DELAY).fail();
     }
-    downloadRunner.assertFailed();
-    downloadManagerListener.clearDownloadError();
 
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+    downloader.assertReleased().assertStartCount(MIN_RETRY_COUNT + 1);
+    runner.getTask().assertFailed();
+    downloadManagerListener.blockUntilTasksComplete();
   }
 
   @Test
-  public void testDownloadNoRetryWhenCanceled() throws Throwable {
-    DownloadRunner downloadRunner = createDownloadRunner(uri1).ignoreInterrupts();
-    downloadRunner.downloader.enableDownloadIOException = true;
-    downloadRunner.postAction().assertStarted();
+  public void downloadFails_retries() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    runner.postDownloadAction();
+    FakeDownloader downloader = runner.getDownloader(0);
 
-    DownloadRunner removeRunner = createRemoveRunner(uri1).postAction();
-
-    downloadRunner.unblock().assertCanceled();
-    removeRunner.unblock();
-
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  @Test
-  public void testDownloadRetriesThenContinues() throws Throwable {
-    DownloadRunner downloadRunner = createDownloadRunner(uri1);
-    downloadRunner.postAction();
-    FakeDownloader fakeDownloader = downloadRunner.downloader;
-    fakeDownloader.enableDownloadIOException = true;
-    for (int i = 0; i <= MIN_RETRY_COUNT; i++) {
-      fakeDownloader.assertStarted(MAX_RETRY_DELAY);
-      if (i == MIN_RETRY_COUNT) {
-        fakeDownloader.enableDownloadIOException = false;
-      }
-      fakeDownloader.unblock();
+    for (int i = 0; i < MIN_RETRY_COUNT; i++) {
+      downloader.assertStarted(MAX_RETRY_DELAY).fail();
     }
-    downloadRunner.assertCompleted();
+    downloader.assertStarted(MAX_RETRY_DELAY).unblock();
 
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+    downloader.assertReleased().assertStartCount(MIN_RETRY_COUNT + 1);
+    runner.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksComplete();
   }
 
   @Test
-  @SuppressWarnings({"NonAtomicVolatileUpdate", "NonAtomicOperationOnVolatileField"})
-  public void testDownloadRetryCountResetsOnProgress() throws Throwable {
-    DownloadRunner downloadRunner = createDownloadRunner(uri1);
-    downloadRunner.postAction();
-    FakeDownloader fakeDownloader = downloadRunner.downloader;
-    fakeDownloader.enableDownloadIOException = true;
-    fakeDownloader.downloadedBytes = 0;
-    for (int i = 0; i <= MIN_RETRY_COUNT + 10; i++) {
-      fakeDownloader.assertStarted(MAX_RETRY_DELAY);
-      fakeDownloader.downloadedBytes++;
-      if (i == MIN_RETRY_COUNT + 10) {
-        fakeDownloader.enableDownloadIOException = false;
-      }
-      fakeDownloader.unblock();
+  public void downloadProgressOnRetry_retryCountResets() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    runner.postDownloadAction();
+    FakeDownloader downloader = runner.getDownloader(0);
+
+    int tooManyRetries = MIN_RETRY_COUNT + 10;
+    for (int i = 0; i < tooManyRetries; i++) {
+      downloader.increaseDownloadedByteCount();
+      downloader.assertStarted(MAX_RETRY_DELAY).fail();
     }
-    downloadRunner.assertCompleted();
+    downloader.assertStarted(MAX_RETRY_DELAY).unblock();
 
+    downloader.assertReleased().assertStartCount(tooManyRetries + 1);
+    runner.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksComplete();
+  }
+
+  @Test
+  public void removeCancelsDownload() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    FakeDownloader downloader1 = runner.getDownloader(0);
+
+    runner.postDownloadAction();
+    downloader1.assertStarted();
+    runner.postRemoveAction();
+
+    downloader1.assertCanceled().assertStartCount(1);
+    runner.getDownloader(1).unblock().assertNotCanceled();
     downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
   }
 
   @Test
-  public void testDifferentMediaDownloadActionsStartInParallel() throws Throwable {
-    doTestDownloadersRunInParallel(createDownloadRunner(uri1), createDownloadRunner(uri2));
-  }
+  public void downloadNotCancelRemove() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    FakeDownloader downloader1 = runner.getDownloader(0);
 
-  @Test
-  public void testDifferentMediaDifferentActionsStartInParallel() throws Throwable {
-    doTestDownloadersRunInParallel(createDownloadRunner(uri1), createRemoveRunner(uri2));
-  }
+    runner.postRemoveAction();
+    downloader1.assertStarted();
+    runner.postDownloadAction();
 
-  @Test
-  public void testSameMediaDownloadActionsStartInParallel() throws Throwable {
-    doTestDownloadersRunInParallel(createDownloadRunner(uri1), createDownloadRunner(uri1));
-  }
-
-  @Test
-  public void testSameMediaRemoveActionWaitsDownloadAction() throws Throwable {
-    doTestDownloadersRunSequentially(createDownloadRunner(uri1), createRemoveRunner(uri1));
-  }
-
-  @Test
-  public void testSameMediaDownloadActionWaitsRemoveAction() throws Throwable {
-    doTestDownloadersRunSequentially(createRemoveRunner(uri1), createDownloadRunner(uri1));
-  }
-
-  @Test
-  public void testSameMediaRemoveActionWaitsRemoveAction() throws Throwable {
-    doTestDownloadersRunSequentially(createRemoveRunner(uri1), createRemoveRunner(uri1));
-  }
-
-  @Test
-  public void testSameMediaMultipleActions() throws Throwable {
-    DownloadRunner downloadAction1 = createDownloadRunner(uri1).ignoreInterrupts();
-    DownloadRunner downloadAction2 = createDownloadRunner(uri1).ignoreInterrupts();
-    DownloadRunner removeAction1 = createRemoveRunner(uri1);
-    DownloadRunner downloadAction3 = createDownloadRunner(uri1);
-    DownloadRunner removeAction2 = createRemoveRunner(uri1);
-
-    // Two download actions run in parallel.
-    downloadAction1.postAction().assertStarted();
-    downloadAction2.postAction().assertStarted();
-    // removeAction1 is added. It interrupts the two download actions' threads but they are
-    // configured to ignore it so removeAction1 doesn't start.
-    removeAction1.postAction().assertDoesNotStart();
-
-    // downloadAction2 finishes but it isn't enough to start removeAction1.
-    downloadAction2.unblock().assertCanceled();
-    removeAction1.assertDoesNotStart();
-    // downloadAction3 is postAction to DownloadManager but it waits for removeAction1 to finish.
-    downloadAction3.postAction().assertDoesNotStart();
-
-    // When downloadAction1 finishes, removeAction1 starts.
-    downloadAction1.unblock().assertCanceled();
-    removeAction1.assertStarted();
-    // downloadAction3 still waits removeAction1
-    downloadAction3.assertDoesNotStart();
-
-    // removeAction2 is posted. removeAction1 and downloadAction3 is canceled so removeAction2
-    // starts immediately.
-    removeAction2.postAction();
-    removeAction1.assertCanceled();
-    downloadAction3.assertCanceled();
-    removeAction2.assertStarted().unblock().assertCompleted();
+    downloader1.unblock().assertNotCanceled();
+    runner.getDownloader(1).unblock().assertNotCanceled();
     downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
   }
 
   @Test
-  public void testMultipleRemoveActionWaitsLastCancelsAllOther() throws Throwable {
-    DownloadRunner removeAction1 = createRemoveRunner(uri1).ignoreInterrupts();
-    DownloadRunner removeAction2 = createRemoveRunner(uri1);
-    DownloadRunner removeAction3 = createRemoveRunner(uri1);
+  public void secondSameRemoveActionIgnored() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    FakeDownloader downloader1 = runner.getDownloader(0);
 
-    removeAction1.postAction().assertStarted();
-    removeAction2.postAction().assertDoesNotStart();
-    removeAction3.postAction().assertDoesNotStart();
-
-    removeAction2.assertCanceled();
-
-    removeAction1.unblock().assertCanceled();
-    removeAction3.assertStarted().unblock().assertCompleted();
+    runner.postRemoveAction();
+    downloader1.assertStarted();
+    runner.postRemoveAction();
 
+    downloader1.unblock().assertNotCanceled();
+    runner.getTask().assertCompleted();
+    runner.assertCreatedDownloaderCount(1);
     downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
   }
 
   @Test
-  public void testGetTasks() throws Throwable {
-    DownloadRunner removeAction = createRemoveRunner(uri1);
-    DownloadRunner downloadAction1 = createDownloadRunner(uri1);
-    DownloadRunner downloadAction2 = createDownloadRunner(uri1);
+  public void secondSameDownloadActionIgnored() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    FakeDownloader downloader1 = runner.getDownloader(0);
 
-    removeAction.postAction().assertStarted();
-    downloadAction1.postAction().assertDoesNotStart();
-    downloadAction2.postAction().assertDoesNotStart();
+    runner.postDownloadAction();
+    downloader1.assertStarted();
+    runner.postDownloadAction();
+
+    downloader1.unblock().assertNotCanceled();
+    runner.getTask().assertCompleted();
+    runner.assertCreatedDownloaderCount(1);
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void differentDownloadActionsMerged() throws Throwable {
+    DownloadRunner runner = new DownloadRunner(uri1);
+    FakeDownloader downloader1 = runner.getDownloader(0);
+
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+
+    runner.postDownloadAction(streamKey1);
+    downloader1.assertStarted();
+    runner.postDownloadAction(streamKey2);
+
+    downloader1.unblock().assertCanceled();
+
+    FakeDownloader downloader2 = runner.getDownloader(1);
+    downloader2.assertStarted();
+    assertThat(downloader2.action.keys).containsExactly(streamKey1, streamKey2);
+    downloader2.unblock();
+
+    runner.getTask().assertCompleted();
+    runner.assertCreatedDownloaderCount(2);
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void actionsForDifferentContent_executedInParallel() throws Throwable {
+    DownloadRunner runner1 = new DownloadRunner(uri1).postDownloadAction();
+    DownloadRunner runner2 = new DownloadRunner(uri2).postDownloadAction();
+    FakeDownloader downloader1 = runner1.getDownloader(0);
+    FakeDownloader downloader2 = runner2.getDownloader(0);
+
+    downloader1.assertStarted();
+    downloader2.assertStarted();
+    downloader1.unblock();
+    downloader2.unblock();
+
+    runner1.getTask().assertCompleted();
+    runner2.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void actionsForDifferentContent_ifMaxDownloadIs1_executedSequentially() throws Throwable {
+    setUpDownloadManager(1);
+    DownloadRunner runner1 = new DownloadRunner(uri1).postDownloadAction();
+    DownloadRunner runner2 = new DownloadRunner(uri2).postDownloadAction();
+    FakeDownloader downloader1 = runner1.getDownloader(0);
+    FakeDownloader downloader2 = runner2.getDownloader(0);
+
+    downloader1.assertStarted();
+    downloader2.assertDoesNotStart();
+    downloader1.unblock();
+    downloader2.assertStarted();
+    downloader2.unblock();
+
+    runner1.getTask().assertCompleted();
+    runner2.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void removeActionForDifferentContent_ifMaxDownloadIs1_executedInParallel()
+      throws Throwable {
+    setUpDownloadManager(1);
+    DownloadRunner runner1 = new DownloadRunner(uri1).postDownloadAction();
+    DownloadRunner runner2 = new DownloadRunner(uri2).postRemoveAction();
+    FakeDownloader downloader1 = runner1.getDownloader(0);
+    FakeDownloader downloader2 = runner2.getDownloader(0);
+
+    downloader1.assertStarted();
+    downloader2.assertStarted();
+    downloader1.unblock();
+    downloader2.unblock();
+
+    runner1.getTask().assertCompleted();
+    runner2.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void downloadActionFollowingRemove_ifMaxDownloadIs1_isNotStarted() throws Throwable {
+    setUpDownloadManager(1);
+    DownloadRunner runner1 = new DownloadRunner(uri1).postDownloadAction();
+    DownloadRunner runner2 = new DownloadRunner(uri2).postRemoveAction().postDownloadAction();
+    FakeDownloader downloader1 = runner1.getDownloader(0);
+    FakeDownloader downloader2 = runner2.getDownloader(0);
+    FakeDownloader downloader3 = runner2.getDownloader(1);
+
+    downloader1.assertStarted();
+    downloader2.assertStarted();
+    downloader2.unblock();
+    downloader3.assertDoesNotStart();
+    downloader1.unblock();
+    downloader3.assertStarted();
+    downloader3.unblock();
+
+    runner1.getTask().assertCompleted();
+    runner2.getTask().assertCompleted();
+    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
+  }
+
+  @Test
+  public void getTasks_returnTasks() {
+    TaskWrapper task1 = new DownloadRunner(uri1).postDownloadAction().getTask();
+    TaskWrapper task2 = new DownloadRunner(uri2).postDownloadAction().getTask();
+    TaskWrapper task3 = new DownloadRunner(uri3).postRemoveAction().getTask();
+
+    DownloadState[] states = downloadManager.getAllDownloadStates();
 
-    TaskState[] states = downloadManager.getAllTaskStates();
     assertThat(states).hasLength(3);
-    assertThat(states[0].action).isEqualTo(removeAction.action);
-    assertThat(states[1].action).isEqualTo(downloadAction1.action);
-    assertThat(states[2].action).isEqualTo(downloadAction2.action);
+    String[] taskIds = {task1.taskId, task2.taskId, task3.taskId};
+    String[] stateTaskIds = {states[0].id, states[1].id, states[2].id};
+    assertThat(stateTaskIds).isEqualTo(taskIds);
   }
 
   @Test
-  public void testMultipleWaitingDownloadActionStartsInParallel() throws Throwable {
-    DownloadRunner removeAction = createRemoveRunner(uri1);
-    DownloadRunner downloadAction1 = createDownloadRunner(uri1);
-    DownloadRunner downloadAction2 = createDownloadRunner(uri1);
+  public void stopAndResume() throws Throwable {
+    DownloadRunner runner1 = new DownloadRunner(uri1);
+    DownloadRunner runner2 = new DownloadRunner(uri2);
+    DownloadRunner runner3 = new DownloadRunner(uri3);
 
-    removeAction.postAction().assertStarted();
-    downloadAction1.postAction().assertDoesNotStart();
-    downloadAction2.postAction().assertDoesNotStart();
-
-    removeAction.unblock().assertCompleted();
-    downloadAction1.assertStarted();
-    downloadAction2.assertStarted();
-    downloadAction1.unblock().assertCompleted();
-    downloadAction2.unblock().assertCompleted();
-
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  @Test
-  public void testDifferentMediaDownloadActionsPreserveOrder() throws Throwable {
-    DownloadRunner removeRunner = createRemoveRunner(uri1).ignoreInterrupts();
-    DownloadRunner downloadRunner1 = createDownloadRunner(uri1);
-    DownloadRunner downloadRunner2 = createDownloadRunner(uri2);
-
-    removeRunner.postAction().assertStarted();
-    downloadRunner1.postAction().assertDoesNotStart();
-    downloadRunner2.postAction().assertDoesNotStart();
-
-    removeRunner.unblock().assertCompleted();
-    downloadRunner1.assertStarted();
-    downloadRunner2.assertStarted();
-    downloadRunner1.unblock().assertCompleted();
-    downloadRunner2.unblock().assertCompleted();
-
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  @Test
-  public void testDifferentMediaRemoveActionsDoNotPreserveOrder() throws Throwable {
-    DownloadRunner downloadRunner = createDownloadRunner(uri1).ignoreInterrupts();
-    DownloadRunner removeRunner1 = createRemoveRunner(uri1);
-    DownloadRunner removeRunner2 = createRemoveRunner(uri2);
-
-    downloadRunner.postAction().assertStarted();
-    removeRunner1.postAction().assertDoesNotStart();
-    removeRunner2.postAction().assertStarted();
-
-    downloadRunner.unblock().assertCanceled();
-    removeRunner2.unblock().assertCompleted();
-
-    removeRunner1.assertStarted();
-    removeRunner1.unblock().assertCompleted();
-
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  @Test
-  public void testStopAndResume() throws Throwable {
-    DownloadRunner download1Runner = createDownloadRunner(uri1);
-    DownloadRunner remove2Runner = createRemoveRunner(uri2);
-    DownloadRunner download2Runner = createDownloadRunner(uri2);
-    DownloadRunner remove1Runner = createRemoveRunner(uri1);
-    DownloadRunner download3Runner = createDownloadRunner(uri3);
-
-    download1Runner.postAction().assertStarted();
-    remove2Runner.postAction().assertStarted();
-    download2Runner.postAction().assertDoesNotStart();
+    runner1.postDownloadAction().getTask().assertStarted();
+    runner2.postRemoveAction().getTask().assertStarted();
+    runner2.postDownloadAction();
 
     runOnMainThread(() -> downloadManager.stopDownloads());
 
-    download1Runner.assertStopped();
+    runner1.getTask().assertQueued();
 
     // remove actions aren't stopped.
-    remove2Runner.unblock().assertCompleted();
+    runner2.getDownloader(0).unblock().assertReleased();
+    runner2.getTask().assertQueued();
     // Although remove2 is finished, download2 doesn't start.
-    download2Runner.assertDoesNotStart();
+    runner2.getDownloader(1).assertDoesNotStart();
 
     // When a new remove action is added, it cancels stopped download actions with the same media.
-    remove1Runner.postAction();
-    download1Runner.assertCanceled();
-    remove1Runner.assertStarted().unblock().assertCompleted();
+    runner1.postRemoveAction();
+    runner1.getDownloader(1).assertStarted().unblock();
+    runner1.getTask().assertCompleted();
 
     // New download actions can be added but they don't start.
-    download3Runner.postAction().assertDoesNotStart();
+    runner3.postDownloadAction().getDownloader(0).assertDoesNotStart();
 
     runOnMainThread(() -> downloadManager.startDownloads());
 
-    download2Runner.assertStarted().unblock().assertCompleted();
-    download3Runner.assertStarted().unblock().assertCompleted();
-
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  @Test
-  public void testResumeBeforeTotallyStopped() throws Throwable {
-    setUpDownloadManager(2);
-    DownloadRunner download1Runner = createDownloadRunner(uri1).ignoreInterrupts();
-    DownloadRunner download2Runner = createDownloadRunner(uri2);
-    DownloadRunner download3Runner = createDownloadRunner(uri3);
-
-    download1Runner.postAction().assertStarted();
-    download2Runner.postAction().assertStarted();
-    // download3 doesn't start as DM was configured to run two downloads in parallel.
-    download3Runner.postAction().assertDoesNotStart();
-
-    runOnMainThread(() -> downloadManager.stopDownloads());
-
-    // download1 doesn't stop yet as it ignores interrupts.
-    download2Runner.assertStopped();
-
-    runOnMainThread(() -> downloadManager.startDownloads());
-
-    // download2 starts immediately.
-    download2Runner.assertStarted();
-
-    // download3 doesn't start as download1 still holds its slot.
-    download3Runner.assertDoesNotStart();
-
-    // when unblocked download1 stops and starts immediately.
-    download1Runner.unblock().assertStopped().assertStarted();
-
-    download1Runner.unblock();
-    download2Runner.unblock();
-    download3Runner.unblock();
+    runner2.getDownloader(1).assertStarted().unblock();
+    runner3.getDownloader(0).assertStarted().unblock();
 
     downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
   }
@@ -419,101 +442,103 @@ public class DownloadManagerTest {
     }
   }
 
-  private void doTestDownloaderRuns(DownloadRunner runner) throws Throwable {
-    runner.postAction().assertStarted().unblock().assertCompleted();
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  private void doTestDownloadersRunSequentially(DownloadRunner runner1, DownloadRunner runner2)
-      throws Throwable {
-    runner1.ignoreInterrupts().postAction().assertStarted();
-    runner2.postAction().assertDoesNotStart();
-
-    runner1.unblock();
-    runner2.assertStarted();
-
-    runner2.unblock().assertCompleted();
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  private void doTestDownloadersRunInParallel(DownloadRunner runner1, DownloadRunner runner2)
-      throws Throwable {
-    runner1.postAction().assertStarted();
-    runner2.postAction().assertStarted();
-    runner1.unblock().assertCompleted();
-    runner2.unblock().assertCompleted();
-    downloadManagerListener.blockUntilTasksCompleteAndThrowAnyDownloadError();
-  }
-
-  private DownloadRunner createDownloadRunner(Uri uri) {
-    return new DownloadRunner(uri, /* isRemoveAction= */ false);
-  }
-
-  private DownloadRunner createRemoveRunner(Uri uri) {
-    return new DownloadRunner(uri, /* isRemoveAction= */ true);
-  }
-
   private void runOnMainThread(final Runnable r) {
     dummyMainThread.runOnMainThread(r);
   }
 
-  private class DownloadRunner {
+  private final class DownloadRunner {
 
-    public final DownloadAction action;
-    public final FakeDownloader downloader;
+    private final Uri uri;
+    private final ArrayList<FakeDownloader> downloaders;
+    private int createdDownloaderCount = 0;
+    private FakeDownloader downloader;
+    private TaskWrapper taskWrapper;
 
-    private DownloadRunner(Uri uri, boolean isRemoveAction) {
-      action =
-          isRemoveAction
-              ? DownloadAction.createRemoveAction(
-                  DownloadAction.TYPE_PROGRESSIVE, uri, /* customCacheKey= */ null)
-              : DownloadAction.createDownloadAction(
-                  DownloadAction.TYPE_PROGRESSIVE,
-                  uri,
-                  /* keys= */ Collections.emptyList(),
-                  /* customCacheKey= */ null,
-                  /* data= */ null);
-      downloader = new FakeDownloader(isRemoveAction);
-      downloaderFactory.putFakeDownloader(action, downloader);
+    private DownloadRunner(Uri uri) {
+      this.uri = uri;
+      downloaders = new ArrayList<>();
+      downloader = addDownloader();
+      downloaderFactory.registerDownloadRunner(this);
     }
 
-    private DownloadRunner postAction() {
+    private DownloadRunner postRemoveAction() {
+      return postAction(createRemoveAction(uri));
+    }
+
+    private DownloadRunner postDownloadAction(StreamKey... keys) {
+      return postAction(createDownloadAction(uri, keys));
+    }
+
+    private DownloadRunner postAction(DownloadAction action) {
       runOnMainThread(() -> downloadManager.handleAction(action));
+      if (taskWrapper == null) {
+        taskWrapper = new TaskWrapper(action.id);
+      } else {
+        assertThat(action.id).isEqualTo(taskWrapper.taskId);
+      }
       return this;
     }
 
-    private DownloadRunner assertDoesNotStart() throws InterruptedException {
-      Thread.sleep(ASSERT_FALSE_TIME);
-      assertThat(downloader.started.getCount()).isEqualTo(1);
-      return this;
+    private synchronized FakeDownloader addDownloader() {
+      FakeDownloader fakeDownloader = new FakeDownloader();
+      downloaders.add(fakeDownloader);
+      return fakeDownloader;
     }
 
-    private DownloadRunner assertStarted() throws InterruptedException {
-      downloader.assertStarted(ASSERT_TRUE_TIMEOUT);
-      return assertState(TaskState.STATE_STARTED);
+    private synchronized FakeDownloader getDownloader(int index) {
+      while (downloaders.size() <= index) {
+        addDownloader();
+      }
+      return downloaders.get(index);
     }
 
-    private DownloadRunner assertCompleted() {
-      return assertState(TaskState.STATE_COMPLETED);
+    private synchronized Downloader createDownloader(DownloadAction action) {
+      downloader = getDownloader(createdDownloaderCount++);
+      downloader.action = action;
+      return downloader;
     }
 
-    private DownloadRunner assertFailed() {
-      return assertState(TaskState.STATE_FAILED);
+    private TaskWrapper getTask() {
+      return taskWrapper;
     }
 
-    private DownloadRunner assertCanceled() {
-      return assertState(TaskState.STATE_CANCELED);
+    public void setTask(TaskWrapper taskWrapper) {
+      this.taskWrapper = taskWrapper;
     }
 
-    private DownloadRunner assertStopped() {
-      return assertState(TaskState.STATE_QUEUED);
+    private void assertCreatedDownloaderCount(int count) {
+      assertThat(createdDownloaderCount).isEqualTo(count);
+    }
+  }
+
+  private final class TaskWrapper {
+    private final String taskId;
+
+    private TaskWrapper(String taskId) {
+      this.taskId = taskId;
     }
 
-    private DownloadRunner assertState(@State int expectedState) {
+    private TaskWrapper assertStarted() throws InterruptedException {
+      return assertState(DownloadState.STATE_STARTED);
+    }
+
+    private TaskWrapper assertCompleted() {
+      return assertState(DownloadState.STATE_COMPLETED);
+    }
+
+    private TaskWrapper assertFailed() {
+      return assertState(DownloadState.STATE_FAILED);
+    }
+
+    private TaskWrapper assertQueued() {
+      return assertState(DownloadState.STATE_QUEUED);
+    }
+
+    private TaskWrapper assertState(@State int expectedState) {
       while (true) {
         Integer state = null;
         try {
-          state = downloadManagerListener.pollStateChange(action, ASSERT_TRUE_TIMEOUT);
+          state = downloadManagerListener.pollStateChange(taskId, ASSERT_TRUE_TIMEOUT);
         } catch (InterruptedException e) {
           fail(e.getMessage());
         }
@@ -523,69 +548,98 @@ public class DownloadManagerTest {
       }
     }
 
-    private DownloadRunner unblock() {
-      downloader.unblock();
-      return this;
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (o == null || getClass() != o.getClass()) {
+        return false;
+      }
+      return taskId.equals(((TaskWrapper) o).taskId);
     }
 
-    private DownloadRunner ignoreInterrupts() {
-      downloader.ignoreInterrupts = true;
-      return this;
+    @Override
+    public int hashCode() {
+      return taskId.hashCode();
     }
   }
 
-  private static class FakeDownloaderFactory implements DownloaderFactory {
+  private static DownloadAction createDownloadAction(Uri uri, StreamKey... keys) {
+    return DownloadAction.createDownloadAction(
+        DownloadAction.TYPE_PROGRESSIVE,
+        uri,
+        Arrays.asList(keys),
+        /* customCacheKey= */ null,
+        /* data= */ null);
+  }
 
-    public IdentityHashMap<DownloadAction, FakeDownloader> downloaders;
+  private static DownloadAction createRemoveAction(Uri uri) {
+    return DownloadAction.createRemoveAction(
+        DownloadAction.TYPE_PROGRESSIVE, uri, /* customCacheKey= */ null);
+  }
+
+  private static final class FakeDownloaderFactory implements DownloaderFactory {
+
+    private final HashMap<Uri, DownloadRunner> downloaders;
 
     public FakeDownloaderFactory() {
-      downloaders = new IdentityHashMap<>();
+      downloaders = new HashMap<>();
     }
 
-    public void putFakeDownloader(DownloadAction action, FakeDownloader downloader) {
-      downloaders.put(action, downloader);
+    public void registerDownloadRunner(DownloadRunner downloadRunner) {
+      assertThat(downloaders.put(downloadRunner.uri, downloadRunner)).isNull();
     }
 
     @Override
     public Downloader createDownloader(DownloadAction action) {
-      return downloaders.get(action);
+      return downloaders.get(action.uri).createDownloader(action);
     }
   }
 
-  private static class FakeDownloader implements Downloader {
+  private static final class FakeDownloader implements Downloader {
 
     private final com.google.android.exoplayer2.util.ConditionVariable blocker;
-    private final boolean isRemove;
 
+    private DownloadAction action;
     private CountDownLatch started;
-    private boolean ignoreInterrupts;
+    private volatile boolean interrupted;
+    private volatile boolean cancelled;
     private volatile boolean enableDownloadIOException;
-    private volatile int downloadedBytes = C.LENGTH_UNSET;
+    private volatile int downloadedBytes;
+    private volatile int startCount;
 
-    private FakeDownloader(boolean isRemove) {
-      this.isRemove = isRemove;
+    private FakeDownloader() {
       this.started = new CountDownLatch(1);
       this.blocker = new com.google.android.exoplayer2.util.ConditionVariable();
+      downloadedBytes = C.LENGTH_UNSET;
     }
 
+    @SuppressWarnings({"NonAtomicOperationOnVolatileField", "NonAtomicVolatileUpdate"})
     @Override
     public void download() throws InterruptedException, IOException {
-      assertThat(isRemove).isFalse();
+      // It's ok to update this directly as no other thread will update it.
+      startCount++;
+      assertThat(action.isRemoveAction).isFalse();
       started.countDown();
       block();
       if (enableDownloadIOException) {
+        enableDownloadIOException = false;
         throw new IOException();
       }
     }
 
     @Override
     public void cancel() {
-      // Do nothing.
+      cancelled = true;
     }
 
+    @SuppressWarnings({"NonAtomicOperationOnVolatileField", "NonAtomicVolatileUpdate"})
     @Override
     public void remove() throws InterruptedException {
-      assertThat(isRemove).isTrue();
+      // It's ok to update this directly as no other thread will update it.
+      startCount++;
+      assertThat(action.isRemoveAction).isTrue();
       started.countDown();
       block();
     }
@@ -597,9 +651,8 @@ public class DownloadManagerTest {
             blocker.block();
             break;
           } catch (InterruptedException e) {
-            if (!ignoreInterrupts) {
-              throw e;
-            }
+            interrupted = true;
+            throw e;
           }
         }
       } finally {
@@ -607,17 +660,56 @@ public class DownloadManagerTest {
       }
     }
 
+    private FakeDownloader assertStarted() throws InterruptedException {
+      return assertStarted(ASSERT_TRUE_TIMEOUT);
+    }
+
     private FakeDownloader assertStarted(int timeout) throws InterruptedException {
       assertThat(started.await(timeout, TimeUnit.MILLISECONDS)).isTrue();
       started = new CountDownLatch(1);
       return this;
     }
 
+    private FakeDownloader assertStartCount(int count) throws InterruptedException {
+      assertThat(startCount).isEqualTo(count);
+      return this;
+    }
+
+    private FakeDownloader assertReleased() throws InterruptedException {
+      int count = 0;
+      while (started.await(ASSERT_TRUE_TIMEOUT, TimeUnit.MILLISECONDS)) {
+        if (count++ >= MAX_STARTS_BEFORE_RELEASED) {
+          fail();
+        }
+        started = new CountDownLatch(1);
+      }
+      return this;
+    }
+
+    private FakeDownloader assertCanceled() throws InterruptedException {
+      assertReleased();
+      assertThat(interrupted).isTrue();
+      assertThat(cancelled).isTrue();
+      return this;
+    }
+
+    private FakeDownloader assertNotCanceled() throws InterruptedException {
+      assertReleased();
+      assertThat(interrupted).isFalse();
+      assertThat(cancelled).isFalse();
+      return this;
+    }
+
     private FakeDownloader unblock() {
       blocker.open();
       return this;
     }
 
+    private FakeDownloader fail() {
+      enableDownloadIOException = true;
+      return unblock();
+    }
+
     @Override
     public long getDownloadedBytes() {
       return downloadedBytes;
@@ -632,5 +724,15 @@ public class DownloadManagerTest {
     public float getDownloadPercentage() {
       return C.PERCENTAGE_UNSET;
     }
+
+    private void assertDoesNotStart() throws InterruptedException {
+      Thread.sleep(ASSERT_FALSE_TIME);
+      assertThat(started.getCount()).isEqualTo(1);
+    }
+
+    @SuppressWarnings({"NonAtomicOperationOnVolatileField", "NonAtomicVolatileUpdate"})
+    private void increaseDownloadedByteCount() {
+      downloadedBytes++;
+    }
   }
 }

library/core/src/test/java/com/google/android/exoplayer2/text/ttml/TtmlDecoderTest.java

@@ -63,6 +63,9 @@ public final class TtmlDecoderTest {
   private static final String FONT_SIZE_INVALID_TTML_FILE = "ttml/font_size_invalid.xml";
   private static final String FONT_SIZE_EMPTY_TTML_FILE = "ttml/font_size_empty.xml";
   private static final String FRAME_RATE_TTML_FILE = "ttml/frame_rate.xml";
+  private static final String BITMAP_REGION_FILE = "ttml/bitmap_percentage_region.xml";
+  private static final String BITMAP_PIXEL_REGION_FILE = "ttml/bitmap_pixel_region.xml";
+  private static final String BITMAP_UNSUPPORTED_REGION_FILE = "ttml/bitmap_unsupported_region.xml";
 
   @Test
   public void testInlineAttributes() throws IOException, SubtitleDecoderException {
@@ -259,56 +262,56 @@ public final class TtmlDecoderTest {
   @Test
   public void testMultipleRegions() throws IOException, SubtitleDecoderException {
     TtmlSubtitle subtitle = getSubtitle(MULTIPLE_REGIONS_TTML_FILE);
-    List<Cue> output = subtitle.getCues(1000000);
-    assertThat(output).hasSize(2);
-    Cue ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("lorem");
-    assertThat(ttmlCue.position).isEqualTo(10f / 100f);
-    assertThat(ttmlCue.line).isEqualTo(10f / 100f);
-    assertThat(ttmlCue.size).isEqualTo(20f / 100f);
+    List<Cue> cues = subtitle.getCues(1000000);
+    assertThat(cues).hasSize(2);
+    Cue cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("lorem");
+    assertThat(cue.position).isEqualTo(10f / 100f);
+    assertThat(cue.line).isEqualTo(10f / 100f);
+    assertThat(cue.size).isEqualTo(20f / 100f);
 
-    ttmlCue = output.get(1);
-    assertThat(ttmlCue.text.toString()).isEqualTo("amet");
-    assertThat(ttmlCue.position).isEqualTo(60f / 100f);
-    assertThat(ttmlCue.line).isEqualTo(10f / 100f);
-    assertThat(ttmlCue.size).isEqualTo(20f / 100f);
+    cue = cues.get(1);
+    assertThat(cue.text.toString()).isEqualTo("amet");
+    assertThat(cue.position).isEqualTo(60f / 100f);
+    assertThat(cue.line).isEqualTo(10f / 100f);
+    assertThat(cue.size).isEqualTo(20f / 100f);
 
-    output = subtitle.getCues(5000000);
-    assertThat(output).hasSize(1);
-    ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("ipsum");
-    assertThat(ttmlCue.position).isEqualTo(40f / 100f);
-    assertThat(ttmlCue.line).isEqualTo(40f / 100f);
-    assertThat(ttmlCue.size).isEqualTo(20f / 100f);
+    cues = subtitle.getCues(5000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("ipsum");
+    assertThat(cue.position).isEqualTo(40f / 100f);
+    assertThat(cue.line).isEqualTo(40f / 100f);
+    assertThat(cue.size).isEqualTo(20f / 100f);
 
-    output = subtitle.getCues(9000000);
-    assertThat(output).hasSize(1);
-    ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("dolor");
-    assertThat(ttmlCue.position).isEqualTo(Cue.DIMEN_UNSET);
-    assertThat(ttmlCue.line).isEqualTo(Cue.DIMEN_UNSET);
-    assertThat(ttmlCue.size).isEqualTo(Cue.DIMEN_UNSET);
+    cues = subtitle.getCues(9000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("dolor");
+    assertThat(cue.position).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.line).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.size).isEqualTo(Cue.DIMEN_UNSET);
     // TODO: Should be as below, once https://github.com/google/ExoPlayer/issues/2953 is fixed.
-    // assertEquals(10f / 100f, ttmlCue.position);
-    // assertEquals(80f / 100f, ttmlCue.line);
-    // assertEquals(1f, ttmlCue.size);
+    // assertEquals(10f / 100f, cue.position);
+    // assertEquals(80f / 100f, cue.line);
+    // assertEquals(1f, cue.size);
 
-    output = subtitle.getCues(21000000);
-    assertThat(output).hasSize(1);
-    ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("She first said this");
-    assertThat(ttmlCue.position).isEqualTo(45f / 100f);
-    assertThat(ttmlCue.line).isEqualTo(45f / 100f);
-    assertThat(ttmlCue.size).isEqualTo(35f / 100f);
-    output = subtitle.getCues(25000000);
-    ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("She first said this\nThen this");
-    output = subtitle.getCues(29000000);
-    assertThat(output).hasSize(1);
-    ttmlCue = output.get(0);
-    assertThat(ttmlCue.text.toString()).isEqualTo("She first said this\nThen this\nFinally this");
-    assertThat(ttmlCue.position).isEqualTo(45f / 100f);
-    assertThat(ttmlCue.line).isEqualTo(45f / 100f);
+    cues = subtitle.getCues(21000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("She first said this");
+    assertThat(cue.position).isEqualTo(45f / 100f);
+    assertThat(cue.line).isEqualTo(45f / 100f);
+    assertThat(cue.size).isEqualTo(35f / 100f);
+    cues = subtitle.getCues(25000000);
+    cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("She first said this\nThen this");
+    cues = subtitle.getCues(29000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text.toString()).isEqualTo("She first said this\nThen this\nFinally this");
+    assertThat(cue.position).isEqualTo(45f / 100f);
+    assertThat(cue.line).isEqualTo(45f / 100f);
   }
 
   @Test
@@ -499,6 +502,91 @@ public final class TtmlDecoderTest {
     assertThat((double) subtitle.getEventTime(3)).isWithin(2000).of(2_002_000_000);
   }
 
+  @Test
+  public void testBitmapPercentageRegion() throws IOException, SubtitleDecoderException {
+    TtmlSubtitle subtitle = getSubtitle(BITMAP_REGION_FILE);
+
+    List<Cue> cues = subtitle.getCues(1000000);
+    assertThat(cues).hasSize(1);
+    Cue cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(24f / 100f);
+    assertThat(cue.line).isEqualTo(28f / 100f);
+    assertThat(cue.size).isEqualTo(51f / 100f);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+
+    cues = subtitle.getCues(4000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(21f / 100f);
+    assertThat(cue.line).isEqualTo(35f / 100f);
+    assertThat(cue.size).isEqualTo(57f / 100f);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+
+    cues = subtitle.getCues(7500000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(24f / 100f);
+    assertThat(cue.line).isEqualTo(28f / 100f);
+    assertThat(cue.size).isEqualTo(51f / 100f);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+  }
+
+  @Test
+  public void testBitmapPixelRegion() throws IOException, SubtitleDecoderException {
+    TtmlSubtitle subtitle = getSubtitle(BITMAP_PIXEL_REGION_FILE);
+
+    List<Cue> cues = subtitle.getCues(1000000);
+    assertThat(cues).hasSize(1);
+    Cue cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(307f / 1280f);
+    assertThat(cue.line).isEqualTo(562f / 720f);
+    assertThat(cue.size).isEqualTo(653f / 1280f);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+
+    cues = subtitle.getCues(4000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(269f / 1280f);
+    assertThat(cue.line).isEqualTo(612f / 720f);
+    assertThat(cue.size).isEqualTo(730f / 1280f);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+  }
+
+  @Test
+  public void testBitmapUnsupportedRegion() throws IOException, SubtitleDecoderException {
+    TtmlSubtitle subtitle = getSubtitle(BITMAP_UNSUPPORTED_REGION_FILE);
+
+    List<Cue> cues = subtitle.getCues(1000000);
+    assertThat(cues).hasSize(1);
+    Cue cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.line).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.size).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+
+    cues = subtitle.getCues(4000000);
+    assertThat(cues).hasSize(1);
+    cue = cues.get(0);
+    assertThat(cue.text).isNull();
+    assertThat(cue.bitmap).isNotNull();
+    assertThat(cue.position).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.line).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.size).isEqualTo(Cue.DIMEN_UNSET);
+    assertThat(cue.bitmapHeight).isEqualTo(Cue.DIMEN_UNSET);
+  }
+
   private void assertSpans(
       TtmlSubtitle subtitle,
       int second,

library/core/src/test/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelectionTest.java

@@ -32,6 +32,7 @@ import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
 import com.google.android.exoplayer2.testutil.FakeClock;
 import com.google.android.exoplayer2.testutil.FakeMediaChunk;
+import com.google.android.exoplayer2.trackselection.TrackSelection.Definition;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.util.MimeTypes;
 import java.util.ArrayList;
@@ -66,15 +67,20 @@ public final class AdaptiveTrackSelectionTest {
   }
 
   @Test
+  @SuppressWarnings("deprecation")
   public void testFactoryUsesInitiallyProvidedBandwidthMeter() {
     BandwidthMeter initialBandwidthMeter = mock(BandwidthMeter.class);
     BandwidthMeter injectedBandwidthMeter = mock(BandwidthMeter.class);
-    Format format = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
-    @SuppressWarnings("deprecation")
-    AdaptiveTrackSelection adaptiveTrackSelection =
+    Format format1 = videoFormat(/* bitrate= */ 500, /* width= */ 320, /* height= */ 240);
+    Format format2 = videoFormat(/* bitrate= */ 1000, /* width= */ 640, /* height= */ 480);
+    TrackSelection[] trackSelections =
         new AdaptiveTrackSelection.Factory(initialBandwidthMeter)
-            .createTrackSelection(new TrackGroup(format), injectedBandwidthMeter, /* tracks= */ 0);
-    adaptiveTrackSelection.updateSelectedTrack(
+            .createTrackSelections(
+                new Definition[] {
+                  new Definition(new TrackGroup(format1, format2), /* tracks= */ 0, 1)
+                },
+                injectedBandwidthMeter);
+    trackSelections[0].updateSelectedTrack(
         /* playbackPositionUs= */ 0,
         /* bufferedDurationUs= */ 0,
         /* availableDurationUs= */ C.TIME_UNSET,

library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/CacheDataSourceTest.java

@@ -247,7 +247,8 @@ public final class CacheDataSourceTest {
     // Read partial at EOS but don't cross it so length is unknown.
     CacheDataSource cacheDataSource = createCacheDataSource(false, true);
     assertReadData(cacheDataSource, dataSpec, true);
-    assertThat(cache.getContentLength(defaultCacheKey)).isEqualTo(C.LENGTH_UNSET);
+    assertThat(ContentMetadata.getContentLength(cache.getContentMetadata(defaultCacheKey)))
+        .isEqualTo(C.LENGTH_UNSET);
 
     // Now do an unbounded request for whole data. This will cause a bounded request from upstream.
     // End of data from upstream shouldn't be mixed up with EOS and cause length set wrong.
@@ -285,7 +286,8 @@ public final class CacheDataSourceTest {
     cacheDataSource.close();
 
     assertThat(upstream.getAndClearOpenedDataSpecs()).hasLength(1);
-    assertThat(cache.getContentLength(defaultCacheKey)).isEqualTo(TEST_DATA.length);
+    assertThat(ContentMetadata.getContentLength(cache.getContentMetadata(defaultCacheKey)))
+        .isEqualTo(TEST_DATA.length);
   }
 
   @Test
@@ -467,11 +469,7 @@ public final class CacheDataSourceTest {
     NavigableSet<CacheSpan> cachedSpans = cache.getCachedSpans(defaultCacheKey);
     for (CacheSpan cachedSpan : cachedSpans) {
       if (cachedSpan.position >= halfDataLength) {
-        try {
-          cache.removeSpan(cachedSpan);
-        } catch (Cache.CacheException e) {
-          // do nothing
-        }
+        cache.removeSpan(cachedSpan);
       }
     }
 
@@ -516,7 +514,9 @@ public final class CacheDataSourceTest {
     // If the request was unbounded then the content length should be cached, either because the
     // content length was known or because EOS was read. If the request was bounded then the content
     // length will not have been determined.
-    assertThat(cache.getContentLength(customCacheKey ? this.customCacheKey : defaultCacheKey))
+    ContentMetadata metadata =
+        cache.getContentMetadata(customCacheKey ? this.customCacheKey : defaultCacheKey);
+    assertThat(ContentMetadata.getContentLength(metadata))
         .isEqualTo(dataSpec.length == C.LENGTH_UNSET ? TEST_DATA.length : C.LENGTH_UNSET);
   }
 

library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/CacheUtilTest.java

@@ -79,8 +79,11 @@ public final class CacheUtilTest {
     }
 
     @Override
-    public long getContentLength(String key) {
-      return contentLength;
+    public ContentMetadata getContentMetadata(String key) {
+      DefaultContentMetadata metadata = new DefaultContentMetadata();
+      ContentMetadataMutations mutations = new ContentMetadataMutations();
+      ContentMetadataMutations.setContentLength(mutations, contentLength);
+      return metadata.copyWithMutationsApplied(mutations);
     }
   }
 

library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/CachedContentIndexTest.java

@@ -154,11 +154,11 @@ public class CachedContentIndexTest {
 
     assertThat(index.assignIdForKey("ABCDE")).isEqualTo(5);
     ContentMetadata metadata = index.get("ABCDE").getMetadata();
-    assertThat(ContentMetadataInternal.getContentLength(metadata)).isEqualTo(10);
+    assertThat(ContentMetadata.getContentLength(metadata)).isEqualTo(10);
 
     assertThat(index.assignIdForKey("KLMNO")).isEqualTo(2);
     ContentMetadata metadata2 = index.get("KLMNO").getMetadata();
-    assertThat(ContentMetadataInternal.getContentLength(metadata2)).isEqualTo(2560);
+    assertThat(ContentMetadata.getContentLength(metadata2)).isEqualTo(2560);
   }
 
   @Test
@@ -172,12 +172,12 @@ public class CachedContentIndexTest {
 
     assertThat(index.assignIdForKey("ABCDE")).isEqualTo(5);
     ContentMetadata metadata = index.get("ABCDE").getMetadata();
-    assertThat(ContentMetadataInternal.getContentLength(metadata)).isEqualTo(10);
-    assertThat(ContentMetadataInternal.getRedirectedUri(metadata)).isEqualTo(Uri.parse("abcde"));
+    assertThat(ContentMetadata.getContentLength(metadata)).isEqualTo(10);
+    assertThat(ContentMetadata.getRedirectedUri(metadata)).isEqualTo(Uri.parse("abcde"));
 
     assertThat(index.assignIdForKey("KLMNO")).isEqualTo(2);
     ContentMetadata metadata2 = index.get("KLMNO").getMetadata();
-    assertThat(ContentMetadataInternal.getContentLength(metadata2)).isEqualTo(2560);
+    assertThat(ContentMetadata.getContentLength(metadata2)).isEqualTo(2560);
   }
 
   @Test
@@ -297,11 +297,11 @@ public class CachedContentIndexTest {
   private void assertStoredAndLoadedEqual(CachedContentIndex index, CachedContentIndex index2)
       throws IOException {
     ContentMetadataMutations mutations1 = new ContentMetadataMutations();
-    ContentMetadataInternal.setContentLength(mutations1, 2560);
+    ContentMetadataMutations.setContentLength(mutations1, 2560);
     index.getOrAdd("KLMNO").applyMetadataMutations(mutations1);
     ContentMetadataMutations mutations2 = new ContentMetadataMutations();
-    ContentMetadataInternal.setContentLength(mutations2, 10);
-    ContentMetadataInternal.setRedirectedUri(mutations2, Uri.parse("abcde"));
+    ContentMetadataMutations.setContentLength(mutations2, 10);
+    ContentMetadataMutations.setRedirectedUri(mutations2, Uri.parse("abcde"));
     index.getOrAdd("ABCDE").applyMetadataMutations(mutations2);
     index.store();
 

library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/SimpleCacheTest.java

@@ -47,6 +47,7 @@ import org.robolectric.RuntimeEnvironment;
 public class SimpleCacheTest {
 
   private static final String KEY_1 = "key1";
+  private static final String KEY_2 = "key2";
 
   private File cacheDir;
 
@@ -105,18 +106,26 @@ public class SimpleCacheTest {
   }
 
   @Test
-  public void testSetGetLength() throws Exception {
+  public void testSetGetContentMetadata() throws Exception {
     SimpleCache simpleCache = getSimpleCache();
 
-    assertThat(simpleCache.getContentLength(KEY_1)).isEqualTo(LENGTH_UNSET);
+    assertThat(ContentMetadata.getContentLength(simpleCache.getContentMetadata(KEY_1)))
+        .isEqualTo(LENGTH_UNSET);
 
-    simpleCache.setContentLength(KEY_1, 15);
-    assertThat(simpleCache.getContentLength(KEY_1)).isEqualTo(15);
+    ContentMetadataMutations mutations = new ContentMetadataMutations();
+    ContentMetadataMutations.setContentLength(mutations, 15);
+    simpleCache.applyContentMetadataMutations(KEY_1, mutations);
+    assertThat(ContentMetadata.getContentLength(simpleCache.getContentMetadata(KEY_1)))
+        .isEqualTo(15);
 
     simpleCache.startReadWrite(KEY_1, 0);
     addCache(simpleCache, KEY_1, 0, 15);
-    simpleCache.setContentLength(KEY_1, 150);
-    assertThat(simpleCache.getContentLength(KEY_1)).isEqualTo(150);
+
+    mutations = new ContentMetadataMutations();
+    ContentMetadataMutations.setContentLength(mutations, 150);
+    simpleCache.applyContentMetadataMutations(KEY_1, mutations);
+    assertThat(ContentMetadata.getContentLength(simpleCache.getContentMetadata(KEY_1)))
+        .isEqualTo(150);
 
     addCache(simpleCache, KEY_1, 140, 10);
 
@@ -124,14 +133,16 @@ public class SimpleCacheTest {
 
     // Check if values are kept after cache is reloaded.
     SimpleCache simpleCache2 = getSimpleCache();
-    assertThat(simpleCache2.getContentLength(KEY_1)).isEqualTo(150);
+    assertThat(ContentMetadata.getContentLength(simpleCache2.getContentMetadata(KEY_1)))
+        .isEqualTo(150);
 
     // Removing the last span shouldn't cause the length be change next time cache loaded
     SimpleCacheSpan lastSpan = simpleCache2.startReadWrite(KEY_1, 145);
     simpleCache2.removeSpan(lastSpan);
     simpleCache2.release();
     simpleCache2 = getSimpleCache();
-    assertThat(simpleCache2.getContentLength(KEY_1)).isEqualTo(150);
+    assertThat(ContentMetadata.getContentLength(simpleCache2.getContentMetadata(KEY_1)))
+        .isEqualTo(150);
   }
 
   @Test
@@ -152,6 +163,40 @@ public class SimpleCacheTest {
     assertCachedDataReadCorrect(cacheSpan2);
   }
 
+  @Test
+  public void testReloadCacheWithoutRelease() throws Exception {
+    SimpleCache simpleCache = getSimpleCache();
+
+    // Write data for KEY_1.
+    CacheSpan cacheSpan1 = simpleCache.startReadWrite(KEY_1, 0);
+    addCache(simpleCache, KEY_1, 0, 15);
+    simpleCache.releaseHoleSpan(cacheSpan1);
+    // Write and remove data for KEY_2.
+    CacheSpan cacheSpan2 = simpleCache.startReadWrite(KEY_2, 0);
+    addCache(simpleCache, KEY_2, 0, 15);
+    simpleCache.releaseHoleSpan(cacheSpan2);
+    simpleCache.removeSpan(simpleCache.getCachedSpans(KEY_2).first());
+
+    // Don't release the cache. This means the index file wont have been written to disk after the
+    // data for KEY_2 was removed. Move the cache instead, so we can reload it without failing the
+    // folder locking check.
+    File cacheDir2 = Util.createTempFile(RuntimeEnvironment.application, "ExoPlayerTest");
+    cacheDir2.delete();
+    cacheDir.renameTo(cacheDir2);
+
+    // Reload the cache from its new location.
+    simpleCache = new SimpleCache(cacheDir2, new NoOpCacheEvictor());
+
+    // Read data back for KEY_1.
+    CacheSpan cacheSpan3 = simpleCache.startReadWrite(KEY_1, 0);
+    assertCachedDataReadCorrect(cacheSpan3);
+
+    // Check the entry for KEY_2 was removed when the cache was reloaded.
+    assertThat(simpleCache.getCachedSpans(KEY_2)).isEmpty();
+
+    Util.recursiveDelete(cacheDir2);
+  }
+
   @Test
   public void testEncryptedIndex() throws Exception {
     byte[] key = "Bar12345Bar12345".getBytes(C.UTF8_NAME); // 128 bit key

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java

@@ -26,6 +26,8 @@ import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.offline.FilteringManifestParser;
+import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.BaseMediaSource;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.DefaultCompositeSequenceableLoaderFactory;
@@ -59,6 +61,7 @@ import java.io.InputStreamReader;
 import java.nio.charset.Charset;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
+import java.util.List;
 import java.util.Locale;
 import java.util.TimeZone;
 import java.util.regex.Matcher;
@@ -75,15 +78,16 @@ public final class DashMediaSource extends BaseMediaSource {
   public static final class Factory implements AdsMediaSource.MediaSourceFactory {
 
     private final DashChunkSource.Factory chunkSourceFactory;
-    private final @Nullable DataSource.Factory manifestDataSourceFactory;
+    @Nullable private final DataSource.Factory manifestDataSourceFactory;
 
-    private @Nullable ParsingLoadable.Parser<? extends DashManifest> manifestParser;
+    @Nullable private ParsingLoadable.Parser<? extends DashManifest> manifestParser;
+    @Nullable private List<StreamKey> streamKeys;
     private CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory;
     private LoadErrorHandlingPolicy loadErrorHandlingPolicy;
     private long livePresentationDelayMs;
     private boolean livePresentationDelayOverridesManifest;
     private boolean isCreateCalled;
-    private @Nullable Object tag;
+    @Nullable private Object tag;
 
     /**
      * Creates a new factory for {@link DashMediaSource}s.
@@ -210,6 +214,19 @@ public final class DashMediaSource extends BaseMediaSource {
       return this;
     }
 
+    /**
+     * Sets a list of {@link StreamKey stream keys} by which the manifest is filtered.
+     *
+     * @param streamKeys A list of {@link StreamKey stream keys}.
+     * @return This factory, for convenience.
+     * @throws IllegalStateException If one of the {@code create} methods has already been called.
+     */
+    public Factory setStreamKeys(List<StreamKey> streamKeys) {
+      Assertions.checkState(!isCreateCalled);
+      this.streamKeys = streamKeys;
+      return this;
+    }
+
     /**
      * Sets the factory to create composite {@link SequenceableLoader}s for when this media source
      * loads data from multiple streams (video, audio etc...). The default is an instance of {@link
@@ -240,6 +257,9 @@ public final class DashMediaSource extends BaseMediaSource {
     public DashMediaSource createMediaSource(DashManifest manifest) {
       Assertions.checkArgument(!manifest.dynamic);
       isCreateCalled = true;
+      if (streamKeys != null && !streamKeys.isEmpty()) {
+        manifest = manifest.copy(streamKeys);
+      }
       return new DashMediaSource(
           manifest,
           /* manifestUri= */ null,
@@ -281,6 +301,9 @@ public final class DashMediaSource extends BaseMediaSource {
       if (manifestParser == null) {
         manifestParser = new DashManifestParser();
       }
+      if (streamKeys != null) {
+        manifestParser = new FilteringManifestParser<>(manifestParser, streamKeys);
+      }
       return new DashMediaSource(
           /* manifest= */ null,
           Assertions.checkNotNull(manifestUri),

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/offline/DashDownloadHelper.java

@@ -16,22 +16,25 @@
 package com.google.android.exoplayer2.source.dash.offline;
 
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.RenderersFactory;
+import com.google.android.exoplayer2.drm.DrmSessionManager;
+import com.google.android.exoplayer2.drm.FrameworkMediaCrypto;
 import com.google.android.exoplayer2.offline.DownloadAction;
 import com.google.android.exoplayer2.offline.DownloadHelper;
 import com.google.android.exoplayer2.offline.StreamKey;
-import com.google.android.exoplayer2.offline.TrackKey;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.dash.manifest.AdaptationSet;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifestParser;
 import com.google.android.exoplayer2.source.dash.manifest.Representation;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.ParsingLoadable;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.List;
 
 /** A {@link DownloadHelper} for DASH streams. */
@@ -39,8 +42,52 @@ public final class DashDownloadHelper extends DownloadHelper<DashManifest> {
 
   private final DataSource.Factory manifestDataSourceFactory;
 
-  public DashDownloadHelper(Uri uri, DataSource.Factory manifestDataSourceFactory) {
-    super(DownloadAction.TYPE_DASH, uri, /* cacheKey= */ null);
+  /**
+   * Creates a DASH download helper.
+   *
+   * <p>The helper uses {@link DownloadHelper#DEFAULT_TRACK_SELECTOR_PARAMETERS} for track selection
+   * and does not support drm protected content.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   */
+  public DashDownloadHelper(
+      Uri uri, DataSource.Factory manifestDataSourceFactory, RenderersFactory renderersFactory) {
+    this(
+        uri,
+        manifestDataSourceFactory,
+        DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS,
+        renderersFactory,
+        /* drmSessionManager= */ null);
+  }
+
+  /**
+   * Creates a DASH download helper.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param trackSelectorParameters {@link DefaultTrackSelector.Parameters} for selecting tracks for
+   *     downloading.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   * @param drmSessionManager An optional {@link DrmSessionManager} used by the renderers created by
+   *     {@code renderersFactory}.
+   */
+  public DashDownloadHelper(
+      Uri uri,
+      DataSource.Factory manifestDataSourceFactory,
+      DefaultTrackSelector.Parameters trackSelectorParameters,
+      RenderersFactory renderersFactory,
+      @Nullable DrmSessionManager<FrameworkMediaCrypto> drmSessionManager) {
+    super(
+        DownloadAction.TYPE_DASH,
+        uri,
+        /* cacheKey= */ null,
+        trackSelectorParameters,
+        renderersFactory,
+        drmSessionManager);
     this.manifestDataSourceFactory = manifestDataSourceFactory;
   }
 
@@ -72,12 +119,8 @@ public final class DashDownloadHelper extends DownloadHelper<DashManifest> {
   }
 
   @Override
-  protected List<StreamKey> toStreamKeys(List<TrackKey> trackKeys) {
-    List<StreamKey> streamKeys = new ArrayList<>(trackKeys.size());
-    for (int i = 0; i < trackKeys.size(); i++) {
-      TrackKey trackKey = trackKeys.get(i);
-      streamKeys.add(new StreamKey(trackKey.periodIndex, trackKey.groupIndex, trackKey.trackIndex));
-    }
-    return streamKeys;
+  protected StreamKey toStreamKey(
+      int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup) {
+    return new StreamKey(periodIndex, trackGroupIndex, trackIndexInTrackGroup);
   }
 }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java

@@ -22,6 +22,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.extractor.Extractor;
+import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.BaseMediaSource;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.DefaultCompositeSequenceableLoaderFactory;
@@ -34,6 +35,7 @@ import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.source.ads.AdsMediaSource;
 import com.google.android.exoplayer2.source.hls.playlist.DefaultHlsPlaylistParserFactory;
 import com.google.android.exoplayer2.source.hls.playlist.DefaultHlsPlaylistTracker;
+import com.google.android.exoplayer2.source.hls.playlist.FilteringHlsPlaylistParserFactory;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser;
@@ -64,12 +66,13 @@ public final class HlsMediaSource extends BaseMediaSource
 
     private HlsExtractorFactory extractorFactory;
     private HlsPlaylistParserFactory playlistParserFactory;
+    @Nullable private List<StreamKey> streamKeys;
     private HlsPlaylistTracker.Factory playlistTrackerFactory;
     private CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory;
     private LoadErrorHandlingPolicy loadErrorHandlingPolicy;
     private boolean allowChunklessPreparation;
     private boolean isCreateCalled;
-    private @Nullable Object tag;
+    @Nullable private Object tag;
 
     /**
      * Creates a new factory for {@link HlsMediaSource}s.
@@ -164,8 +167,8 @@ public final class HlsMediaSource extends BaseMediaSource
     }
 
     /**
-     * Sets the factory from which playlist parsers will be obtained. The default value is created
-     * by calling {@link DefaultHlsPlaylistParserFactory#DefaultHlsPlaylistParserFactory()}.
+     * Sets the factory from which playlist parsers will be obtained. The default value is a {@link
+     * DefaultHlsPlaylistParserFactory}.
      *
      * @param playlistParserFactory An {@link HlsPlaylistParserFactory}.
      * @return This factory, for convenience.
@@ -177,6 +180,19 @@ public final class HlsMediaSource extends BaseMediaSource
       return this;
     }
 
+    /**
+     * Sets a list of {@link StreamKey stream keys} by which the playlists are filtered.
+     *
+     * @param streamKeys A list of {@link StreamKey stream keys}.
+     * @return This factory, for convenience.
+     * @throws IllegalStateException If one of the {@code create} methods has already been called.
+     */
+    public Factory setStreamKeys(List<StreamKey> streamKeys) {
+      Assertions.checkState(!isCreateCalled);
+      this.streamKeys = streamKeys;
+      return this;
+    }
+
     /**
      * Sets the {@link HlsPlaylistTracker} factory. The default value is {@link
      * DefaultHlsPlaylistTracker#FACTORY}.
@@ -232,6 +248,10 @@ public final class HlsMediaSource extends BaseMediaSource
     @Override
     public HlsMediaSource createMediaSource(Uri playlistUri) {
       isCreateCalled = true;
+      if (streamKeys != null) {
+        playlistParserFactory =
+            new FilteringHlsPlaylistParserFactory(playlistParserFactory, streamKeys);
+      }
       return new HlsMediaSource(
           playlistUri,
           hlsDataSourceFactory,

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/offline/HlsDownloadHelper.java

@@ -16,23 +16,26 @@
 package com.google.android.exoplayer2.source.hls.offline;
 
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.RenderersFactory;
+import com.google.android.exoplayer2.drm.DrmSessionManager;
+import com.google.android.exoplayer2.drm.FrameworkMediaCrypto;
 import com.google.android.exoplayer2.offline.DownloadAction;
 import com.google.android.exoplayer2.offline.DownloadHelper;
 import com.google.android.exoplayer2.offline.StreamKey;
-import com.google.android.exoplayer2.offline.TrackKey;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.ParsingLoadable;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -43,8 +46,52 @@ public final class HlsDownloadHelper extends DownloadHelper<HlsPlaylist> {
 
   private int[] renditionGroups;
 
-  public HlsDownloadHelper(Uri uri, DataSource.Factory manifestDataSourceFactory) {
-    super(DownloadAction.TYPE_HLS, uri, /* cacheKey= */ null);
+  /**
+   * Creates a HLS download helper.
+   *
+   * <p>The helper uses {@link DownloadHelper#DEFAULT_TRACK_SELECTOR_PARAMETERS} for track selection
+   * and does not support drm protected content.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   */
+  public HlsDownloadHelper(
+      Uri uri, DataSource.Factory manifestDataSourceFactory, RenderersFactory renderersFactory) {
+    this(
+        uri,
+        manifestDataSourceFactory,
+        DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS,
+        renderersFactory,
+        /* drmSessionManager= */ null);
+  }
+
+  /**
+   * Creates a HLS download helper.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param trackSelectorParameters {@link DefaultTrackSelector.Parameters} for selecting tracks for
+   *     downloading.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   * @param drmSessionManager An optional {@link DrmSessionManager} used by the renderers created by
+   *     {@code renderersFactory}.
+   */
+  public HlsDownloadHelper(
+      Uri uri,
+      DataSource.Factory manifestDataSourceFactory,
+      DefaultTrackSelector.Parameters trackSelectorParameters,
+      RenderersFactory renderersFactory,
+      @Nullable DrmSessionManager<FrameworkMediaCrypto> drmSessionManager) {
+    super(
+        DownloadAction.TYPE_HLS,
+        uri,
+        /* cacheKey= */ null,
+        trackSelectorParameters,
+        renderersFactory,
+        drmSessionManager);
     this.manifestDataSourceFactory = manifestDataSourceFactory;
   }
 
@@ -61,7 +108,7 @@ public final class HlsDownloadHelper extends DownloadHelper<HlsPlaylist> {
       renditionGroups = new int[0];
       return new TrackGroupArray[] {TrackGroupArray.EMPTY};
     }
-    // TODO: Generate track groups as in playback. Reverse the mapping in getDownloadAction.
+    // TODO: Generate track groups as in playback. Reverse the mapping in toStreamKey.
     HlsMasterPlaylist masterPlaylist = (HlsMasterPlaylist) playlist;
     TrackGroup[] trackGroups = new TrackGroup[3];
     renditionGroups = new int[3];
@@ -82,14 +129,9 @@ public final class HlsDownloadHelper extends DownloadHelper<HlsPlaylist> {
   }
 
   @Override
-  protected List<StreamKey> toStreamKeys(List<TrackKey> trackKeys) {
-    List<StreamKey> representationKeys = new ArrayList<>(trackKeys.size());
-    for (int i = 0; i < trackKeys.size(); i++) {
-      TrackKey trackKey = trackKeys.get(i);
-      representationKeys.add(
-          new StreamKey(renditionGroups[trackKey.groupIndex], trackKey.trackIndex));
-    }
-    return representationKeys;
+  protected StreamKey toStreamKey(
+      int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup) {
+    return new StreamKey(renditionGroups[trackGroupIndex], trackIndexInTrackGroup);
   }
 
   private static Format[] toFormats(List<HlsMasterPlaylist.HlsUrl> hlsUrls) {

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistParserFactory.java

@@ -15,40 +15,19 @@
  */
 package com.google.android.exoplayer2.source.hls.playlist;
 
-import com.google.android.exoplayer2.offline.FilteringManifestParser;
-import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.upstream.ParsingLoadable;
-import java.util.Collections;
-import java.util.List;
 
 /** Default implementation for {@link HlsPlaylistParserFactory}. */
 public final class DefaultHlsPlaylistParserFactory implements HlsPlaylistParserFactory {
 
-  private final List<StreamKey> streamKeys;
-
-  /** Creates an instance that does not filter any parsing results. */
-  public DefaultHlsPlaylistParserFactory() {
-    this(Collections.emptyList());
-  }
-
-  /**
-   * Creates an instance that filters the parsing results using the given {@code streamKeys}.
-   *
-   * @param streamKeys See {@link
-   *     FilteringManifestParser#FilteringManifestParser(ParsingLoadable.Parser, List)}.
-   */
-  public DefaultHlsPlaylistParserFactory(List<StreamKey> streamKeys) {
-    this.streamKeys = streamKeys;
-  }
-
   @Override
   public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser() {
-    return new FilteringManifestParser<>(new HlsPlaylistParser(), streamKeys);
+    return new HlsPlaylistParser();
   }
 
   @Override
   public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser(
       HlsMasterPlaylist masterPlaylist) {
-    return new FilteringManifestParser<>(new HlsPlaylistParser(masterPlaylist), streamKeys);
+    return new HlsPlaylistParser(masterPlaylist);
   }
 }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/FilteringHlsPlaylistParserFactory.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.source.hls.playlist;
+
+import com.google.android.exoplayer2.offline.FilteringManifestParser;
+import com.google.android.exoplayer2.offline.StreamKey;
+import com.google.android.exoplayer2.upstream.ParsingLoadable;
+import java.util.List;
+
+/**
+ * A {@link HlsPlaylistParserFactory} that includes only the streams identified by the given stream
+ * keys.
+ */
+public final class FilteringHlsPlaylistParserFactory implements HlsPlaylistParserFactory {
+
+  private final HlsPlaylistParserFactory hlsPlaylistParserFactory;
+  private final List<StreamKey> streamKeys;
+
+  /**
+   * @param hlsPlaylistParserFactory A factory for the parsers of the playlists which will be
+   *     filtered.
+   * @param streamKeys The stream keys. If null or empty then filtering will not occur.
+   */
+  public FilteringHlsPlaylistParserFactory(
+      HlsPlaylistParserFactory hlsPlaylistParserFactory, List<StreamKey> streamKeys) {
+    this.hlsPlaylistParserFactory = hlsPlaylistParserFactory;
+    this.streamKeys = streamKeys;
+  }
+
+  @Override
+  public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser() {
+    return new FilteringManifestParser<>(
+        hlsPlaylistParserFactory.createPlaylistParser(), streamKeys);
+  }
+
+  @Override
+  public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser(
+      HlsMasterPlaylist masterPlaylist) {
+    return new FilteringManifestParser<>(
+        hlsPlaylistParserFactory.createPlaylistParser(masterPlaylist), streamKeys);
+  }
+}

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaPeriod.java

@@ -20,6 +20,7 @@ import android.util.Base64;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.SeekParameters;
 import com.google.android.exoplayer2.extractor.mp4.TrackEncryptionBox;
+import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
@@ -37,12 +38,11 @@ import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.List;
 
-/**
- * A SmoothStreaming {@link MediaPeriod}.
- */
-/* package */ final class SsMediaPeriod implements MediaPeriod,
-    SequenceableLoader.Callback<ChunkSampleStream<SsChunkSource>> {
+/** A SmoothStreaming {@link MediaPeriod}. */
+/* package */ final class SsMediaPeriod
+    implements MediaPeriod, SequenceableLoader.Callback<ChunkSampleStream<SsChunkSource>> {
 
   private static final int INITIALIZATION_VECTOR_SIZE = 8;
 
@@ -112,6 +112,8 @@ import java.util.ArrayList;
     eventDispatcher.mediaPeriodReleased();
   }
 
+  // MediaPeriod implementation.
+
   @Override
   public void prepare(Callback callback, long positionUs) {
     this.callback = callback;
@@ -157,6 +159,16 @@ import java.util.ArrayList;
     return positionUs;
   }
 
+  @Override
+  public List<StreamKey> getStreamKeys(TrackSelection trackSelection) {
+    List<StreamKey> streamKeys = new ArrayList<>(trackSelection.length());
+    int streamElementIndex = trackGroups.indexOf(trackSelection.getTrackGroup());
+    for (int i = 0; i < trackSelection.length(); i++) {
+      streamKeys.add(new StreamKey(streamElementIndex, trackSelection.getIndexInTrackGroup(i)));
+    }
+    return streamKeys;
+  }
+
   @Override
   public void discardBuffer(long positionUs, boolean toKeyframe) {
     for (ChunkSampleStream<SsChunkSource> sampleStream : sampleStreams) {
@@ -211,7 +223,7 @@ import java.util.ArrayList;
     return positionUs;
   }
 
-  // SequenceableLoader.Callback implementation
+  // SequenceableLoader.Callback implementation.
 
   @Override
   public void onContinueLoadingRequested(ChunkSampleStream<SsChunkSource> sampleStream) {
@@ -277,5 +289,4 @@ import java.util.ArrayList;
     data[firstPosition] = data[secondPosition];
     data[secondPosition] = temp;
   }
-
 }

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java

@@ -24,6 +24,8 @@ import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.offline.FilteringManifestParser;
+import com.google.android.exoplayer2.offline.StreamKey;
 import com.google.android.exoplayer2.source.BaseMediaSource;
 import com.google.android.exoplayer2.source.CompositeSequenceableLoaderFactory;
 import com.google.android.exoplayer2.source.DefaultCompositeSequenceableLoaderFactory;
@@ -50,6 +52,7 @@ import com.google.android.exoplayer2.upstream.TransferListener;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.List;
 
 /** A SmoothStreaming {@link MediaSource}. */
 public final class SsMediaSource extends BaseMediaSource
@@ -63,14 +66,15 @@ public final class SsMediaSource extends BaseMediaSource
   public static final class Factory implements AdsMediaSource.MediaSourceFactory {
 
     private final SsChunkSource.Factory chunkSourceFactory;
-    private final @Nullable DataSource.Factory manifestDataSourceFactory;
+    @Nullable private final DataSource.Factory manifestDataSourceFactory;
 
-    private @Nullable ParsingLoadable.Parser<? extends SsManifest> manifestParser;
+    @Nullable private ParsingLoadable.Parser<? extends SsManifest> manifestParser;
+    @Nullable private List<StreamKey> streamKeys;
     private CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory;
     private LoadErrorHandlingPolicy loadErrorHandlingPolicy;
     private long livePresentationDelayMs;
     private boolean isCreateCalled;
-    private @Nullable Object tag;
+    @Nullable private Object tag;
 
     /**
      * Creates a new factory for {@link SsMediaSource}s.
@@ -178,6 +182,19 @@ public final class SsMediaSource extends BaseMediaSource
       return this;
     }
 
+    /**
+     * Sets a list of {@link StreamKey stream keys} by which the manifest is filtered.
+     *
+     * @param streamKeys A list of {@link StreamKey stream keys}.
+     * @return This factory, for convenience.
+     * @throws IllegalStateException If one of the {@code create} methods has already been called.
+     */
+    public Factory setStreamKeys(List<StreamKey> streamKeys) {
+      Assertions.checkState(!isCreateCalled);
+      this.streamKeys = streamKeys;
+      return this;
+    }
+
     /**
      * Sets the factory to create composite {@link SequenceableLoader}s for when this media source
      * loads data from multiple streams (video, audio etc.). The default is an instance of {@link
@@ -208,6 +225,9 @@ public final class SsMediaSource extends BaseMediaSource
     public SsMediaSource createMediaSource(SsManifest manifest) {
       Assertions.checkArgument(!manifest.isLive);
       isCreateCalled = true;
+      if (streamKeys != null && !streamKeys.isEmpty()) {
+        manifest = manifest.copy(streamKeys);
+      }
       return new SsMediaSource(
           manifest,
           /* manifestUri= */ null,
@@ -248,6 +268,9 @@ public final class SsMediaSource extends BaseMediaSource
       if (manifestParser == null) {
         manifestParser = new SsManifestParser();
       }
+      if (streamKeys != null) {
+        manifestParser = new FilteringManifestParser<>(manifestParser, streamKeys);
+      }
       return new SsMediaSource(
           /* manifest= */ null,
           Assertions.checkNotNull(manifestUri),

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/offline/SsDownloadHelper.java

@@ -16,35 +16,83 @@
 package com.google.android.exoplayer2.source.smoothstreaming.offline;
 
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.RenderersFactory;
+import com.google.android.exoplayer2.drm.DrmSessionManager;
+import com.google.android.exoplayer2.drm.FrameworkMediaCrypto;
 import com.google.android.exoplayer2.offline.DownloadAction;
 import com.google.android.exoplayer2.offline.DownloadHelper;
 import com.google.android.exoplayer2.offline.StreamKey;
-import com.google.android.exoplayer2.offline.TrackKey;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifest;
 import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsManifestParser;
+import com.google.android.exoplayer2.source.smoothstreaming.manifest.SsUtil;
+import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.ParsingLoadable;
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
 
 /** A {@link DownloadHelper} for SmoothStreaming streams. */
 public final class SsDownloadHelper extends DownloadHelper<SsManifest> {
 
   private final DataSource.Factory manifestDataSourceFactory;
 
-  public SsDownloadHelper(Uri uri, DataSource.Factory manifestDataSourceFactory) {
-    super(DownloadAction.TYPE_SS, uri, /* cacheKey= */ null);
+  /**
+   * Creates a SmoothStreaming download helper.
+   *
+   * <p>The helper uses {@link DownloadHelper#DEFAULT_TRACK_SELECTOR_PARAMETERS} for track selection
+   * and does not support drm protected content.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   */
+  public SsDownloadHelper(
+      Uri uri, DataSource.Factory manifestDataSourceFactory, RenderersFactory renderersFactory) {
+    this(
+        uri,
+        manifestDataSourceFactory,
+        DownloadHelper.DEFAULT_TRACK_SELECTOR_PARAMETERS,
+        renderersFactory,
+        /* drmSessionManager= */ null);
+  }
+
+  /**
+   * Creates a SmoothStreaming download helper.
+   *
+   * @param uri A manifest {@link Uri}.
+   * @param manifestDataSourceFactory A {@link DataSource.Factory} used to load the manifest.
+   * @param trackSelectorParameters {@link DefaultTrackSelector.Parameters} for selecting tracks for
+   *     downloading.
+   * @param renderersFactory The {@link RenderersFactory} creating the renderers for which tracks
+   *     are selected.
+   * @param drmSessionManager An optional {@link DrmSessionManager} used by the renderers created by
+   *     {@code renderersFactory}.
+   */
+  public SsDownloadHelper(
+      Uri uri,
+      DataSource.Factory manifestDataSourceFactory,
+      DefaultTrackSelector.Parameters trackSelectorParameters,
+      RenderersFactory renderersFactory,
+      @Nullable DrmSessionManager<FrameworkMediaCrypto> drmSessionManager) {
+    super(
+        DownloadAction.TYPE_SS,
+        uri,
+        /* cacheKey= */ null,
+        trackSelectorParameters,
+        renderersFactory,
+        drmSessionManager);
     this.manifestDataSourceFactory = manifestDataSourceFactory;
   }
 
   @Override
   protected SsManifest loadManifest(Uri uri) throws IOException {
     DataSource dataSource = manifestDataSourceFactory.createDataSource();
-    return ParsingLoadable.load(dataSource, new SsManifestParser(), uri, C.DATA_TYPE_MANIFEST);
+    Uri fixedUri = SsUtil.fixManifestUri(uri);
+    return ParsingLoadable.load(dataSource, new SsManifestParser(), fixedUri, C.DATA_TYPE_MANIFEST);
   }
 
   @Override
@@ -58,12 +106,8 @@ public final class SsDownloadHelper extends DownloadHelper<SsManifest> {
   }
 
   @Override
-  protected List<StreamKey> toStreamKeys(List<TrackKey> trackKeys) {
-    List<StreamKey> representationKeys = new ArrayList<>(trackKeys.size());
-    for (int i = 0; i < trackKeys.size(); i++) {
-      TrackKey trackKey = trackKeys.get(i);
-      representationKeys.add(new StreamKey(trackKey.groupIndex, trackKey.trackIndex));
-    }
-    return representationKeys;
+  protected StreamKey toStreamKey(
+      int periodIndex, int trackGroupIndex, int trackIndexInTrackGroup) {
+    return new StreamKey(trackGroupIndex, trackIndexInTrackGroup);
   }
 }

library/ui/src/main/java/com/google/android/exoplayer2/ui/DownloadNotificationUtil.java

@@ -23,7 +23,7 @@ import android.support.annotation.Nullable;
 import android.support.annotation.StringRes;
 import android.support.v4.app.NotificationCompat;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.offline.DownloadManager.TaskState;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 
 /** Helper for creating download notifications. */
 public final class DownloadNotificationUtil {
@@ -33,7 +33,7 @@ public final class DownloadNotificationUtil {
   private DownloadNotificationUtil() {}
 
   /**
-   * Returns a progress notification for the given task states.
+   * Returns a progress notification for the given download states.
    *
    * @param context A context for accessing resources.
    * @param smallIcon A small icon for the notification.
@@ -41,7 +41,7 @@ public final class DownloadNotificationUtil {
    *     above.
    * @param contentIntent An optional content intent to send when the notification is clicked.
    * @param message An optional message to display on the notification.
-   * @param taskStates The task states.
+   * @param downloadStates The download states.
    * @return The notification.
    */
   public static Notification buildProgressNotification(
@@ -50,28 +50,28 @@ public final class DownloadNotificationUtil {
       String channelId,
       @Nullable PendingIntent contentIntent,
       @Nullable String message,
-      TaskState[] taskStates) {
+      DownloadState[] downloadStates) {
     float totalPercentage = 0;
     int downloadTaskCount = 0;
     boolean allDownloadPercentagesUnknown = true;
     boolean haveDownloadedBytes = false;
     boolean haveDownloadTasks = false;
     boolean haveRemoveTasks = false;
-    for (TaskState taskState : taskStates) {
-      if (taskState.state != TaskState.STATE_STARTED
-          && taskState.state != TaskState.STATE_COMPLETED) {
+    for (DownloadState downloadState : downloadStates) {
+      if (downloadState.state != DownloadState.STATE_STARTED
+          && downloadState.state != DownloadState.STATE_COMPLETED) {
         continue;
       }
-      if (taskState.action.isRemoveAction) {
+      if (downloadState.action.isRemoveAction) {
         haveRemoveTasks = true;
         continue;
       }
       haveDownloadTasks = true;
-      if (taskState.downloadPercentage != C.PERCENTAGE_UNSET) {
+      if (downloadState.downloadPercentage != C.PERCENTAGE_UNSET) {
         allDownloadPercentagesUnknown = false;
-        totalPercentage += taskState.downloadPercentage;
+        totalPercentage += downloadState.downloadPercentage;
       }
-      haveDownloadedBytes |= taskState.downloadedBytes > 0;
+      haveDownloadedBytes |= downloadState.downloadedBytes > 0;
       downloadTaskCount++;
     }
 

library/ui/src/main/java/com/google/android/exoplayer2/ui/PlayerView.java

@@ -29,7 +29,6 @@ import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.os.Looper;
 import android.support.annotation.IntDef;
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.content.ContextCompat;
 import android.util.AttributeSet;
@@ -187,8 +186,9 @@ import java.util.List;
  *         <li>Type: {@link AspectRatioFrameLayout}
  *       </ul>
  *   <li><b>{@code exo_shutter}</b> - A view that's made visible when video should be hidden. This
- *       view is typically an opaque view that covers the video surface view, thereby obscuring it
- *       when visible.
+ *       view is typically an opaque view that covers the video surface, thereby obscuring it when
+ *       visible. Obscuring the surface in this way also helps to prevent flicker at the start of
+ *       playback when {@code surface_type="surface_view"}.
  *       <ul>
  *         <li>Type: {@link View}
  *       </ul>
@@ -271,13 +271,13 @@ public class PlayerView extends FrameLayout {
   private static final int SURFACE_TYPE_MONO360_VIEW = 3;
   // LINT.ThenChange(../../../../../../res/values/attrs.xml)
 
-  private final AspectRatioFrameLayout contentFrame;
+  @Nullable private final AspectRatioFrameLayout contentFrame;
   private final View shutterView;
-  private final View surfaceView;
+  @Nullable private final View surfaceView;
   private final ImageView artworkView;
   private final SubtitleView subtitleView;
-  private final @Nullable View bufferingView;
-  private final @Nullable TextView errorMessageView;
+  @Nullable private final View bufferingView;
+  @Nullable private final TextView errorMessageView;
   private final PlayerControlView controller;
   private final ComponentListener componentListener;
   private final FrameLayout overlayFrameLayout;
@@ -285,11 +285,11 @@ public class PlayerView extends FrameLayout {
   private Player player;
   private boolean useController;
   private boolean useArtwork;
-  private @Nullable Drawable defaultArtwork;
+  @Nullable private Drawable defaultArtwork;
   private @ShowBuffering int showBuffering;
   private boolean keepContentOnPlayerReset;
-  private @Nullable ErrorMessageProvider<? super ExoPlaybackException> errorMessageProvider;
-  private @Nullable CharSequence customErrorMessage;
+  @Nullable private ErrorMessageProvider<? super ExoPlaybackException> errorMessageProvider;
+  @Nullable private CharSequence customErrorMessage;
   private int controllerShowTimeoutMs;
   private boolean controllerAutoShow;
   private boolean controllerHideDuringAds;
@@ -474,9 +474,7 @@ public class PlayerView extends FrameLayout {
    * @param newPlayerView The new view to attach to the player.
    */
   public static void switchTargetView(
-      @NonNull Player player,
-      @Nullable PlayerView oldPlayerView,
-      @Nullable PlayerView newPlayerView) {
+      Player player, @Nullable PlayerView oldPlayerView, @Nullable PlayerView newPlayerView) {
     if (oldPlayerView == newPlayerView) {
       return;
     }
@@ -1080,6 +1078,26 @@ public class PlayerView extends FrameLayout {
     }
   }
 
+  /**
+   * Called when there's a change in the aspect ratio of the content being displayed. The default
+   * implementation sets the aspect ratio of the content frame to that of the content, unless the
+   * content view is a {@link SphericalSurfaceView} in which case the frame's aspect ratio is
+   * cleared.
+   *
+   * @param contentAspectRatio The aspect ratio of the content.
+   * @param contentFrame The content frame, or {@code null}.
+   * @param contentView The view that holds the content being displayed, or {@code null}.
+   */
+  protected void onContentAspectRatioChanged(
+      float contentAspectRatio,
+      @Nullable AspectRatioFrameLayout contentFrame,
+      @Nullable View contentView) {
+    if (contentFrame != null) {
+      contentFrame.setAspectRatio(
+          contentView instanceof SphericalSurfaceView ? 0 : contentAspectRatio);
+    }
+  }
+
   private boolean toggleControllerVisibility() {
     if (!useController || player == null) {
       return false;
@@ -1193,9 +1211,8 @@ public class PlayerView extends FrameLayout {
       int drawableWidth = drawable.getIntrinsicWidth();
       int drawableHeight = drawable.getIntrinsicHeight();
       if (drawableWidth > 0 && drawableHeight > 0) {
-        if (contentFrame != null) {
-          contentFrame.setAspectRatio((float) drawableWidth / drawableHeight);
-        }
+        float artworkAspectRatio = (float) drawableWidth / drawableHeight;
+        onContentAspectRatioChanged(artworkAspectRatio, contentFrame, artworkView);
         artworkView.setImageDrawable(drawable);
         artworkView.setVisibility(VISIBLE);
         return true;
@@ -1328,9 +1345,6 @@ public class PlayerView extends FrameLayout {
     @Override
     public void onVideoSizeChanged(
         int width, int height, int unappliedRotationDegrees, float pixelWidthHeightRatio) {
-      if (contentFrame == null) {
-        return;
-      }
       float videoAspectRatio =
           (height == 0 || width == 0) ? 1 : (width * pixelWidthHeightRatio) / height;
 
@@ -1351,11 +1365,9 @@ public class PlayerView extends FrameLayout {
           surfaceView.addOnLayoutChangeListener(this);
         }
         applyTextureViewRotation((TextureView) surfaceView, textureViewRotation);
-      } else if (surfaceView instanceof SphericalSurfaceView) {
-        videoAspectRatio = 0;
       }
 
-      contentFrame.setAspectRatio(videoAspectRatio);
+      onContentAspectRatioChanged(videoAspectRatio, contentFrame, surfaceView);
     }
 
     @Override

library/ui/src/main/java/com/google/android/exoplayer2/ui/TrackSelectionView.java

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.ui;
 
-import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.Dialog;
 import android.content.Context;
@@ -33,13 +32,25 @@ import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector.SelectionOverride;
-import com.google.android.exoplayer2.trackselection.MappingTrackSelector;
+import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.Arrays;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /** A view for making track selections. */
 public class TrackSelectionView extends LinearLayout {
 
+  /** Callback which is invoked when a track selection has been made. */
+  public interface DialogCallback {
+
+    /**
+     * Called when track are selected.
+     *
+     * @param parameters The {@link DefaultTrackSelector.Parameters} for the selected tracks.
+     */
+    void onTracksSelected(DefaultTrackSelector.Parameters parameters);
+  }
+
   private final int selectableItemBackgroundResourceId;
   private final LayoutInflater inflater;
   private final CheckedTextView disableView;
@@ -51,35 +62,64 @@ public class TrackSelectionView extends LinearLayout {
   private TrackNameProvider trackNameProvider;
   private CheckedTextView[][] trackViews;
 
-  private DefaultTrackSelector trackSelector;
+  private @MonotonicNonNull MappedTrackInfo mappedTrackInfo;
   private int rendererIndex;
+  private DefaultTrackSelector.Parameters parameters;
   private TrackGroupArray trackGroups;
   private boolean isDisabled;
-  private @Nullable SelectionOverride override;
+  @Nullable private SelectionOverride override;
 
   /**
    * Gets a pair consisting of a dialog and the {@link TrackSelectionView} that will be shown by it.
    *
-   * @param activity The parent activity.
+   * <p>The dialog shows the current configuration of the provided {@code TrackSelector} and updates
+   * the parameters when closing the dialog.
+   *
+   * @param context The parent context.
    * @param title The dialog's title.
    * @param trackSelector The track selector.
    * @param rendererIndex The index of the renderer.
    * @return The dialog and the {@link TrackSelectionView} that will be shown by it.
    */
   public static Pair<AlertDialog, TrackSelectionView> getDialog(
-      Activity activity,
+      Context context, CharSequence title, DefaultTrackSelector trackSelector, int rendererIndex) {
+    return getDialog(
+        context,
+        title,
+        Assertions.checkNotNull(trackSelector.getCurrentMappedTrackInfo()),
+        rendererIndex,
+        trackSelector.getParameters(),
+        trackSelector::setParameters);
+  }
+
+  /**
+   * Gets a pair consisting of a dialog and the {@link TrackSelectionView} that will be shown by it.
+   *
+   * @param context The parent context.
+   * @param title The dialog's title.
+   * @param mappedTrackInfo The {@link MappedTrackInfo}.
+   * @param rendererIndex The index of the renderer.
+   * @param parameters The {@link DefaultTrackSelector.Parameters}.
+   * @param callback The {@link DialogCallback} invoked when the dialog is closed successfully.
+   * @return The dialog and the {@link TrackSelectionView} that will be shown by it.
+   */
+  public static Pair<AlertDialog, TrackSelectionView> getDialog(
+      Context context,
       CharSequence title,
-      DefaultTrackSelector trackSelector,
-      int rendererIndex) {
-    AlertDialog.Builder builder = new AlertDialog.Builder(activity);
+      MappedTrackInfo mappedTrackInfo,
+      int rendererIndex,
+      DefaultTrackSelector.Parameters parameters,
+      DialogCallback callback) {
+    AlertDialog.Builder builder = new AlertDialog.Builder(context);
 
     // Inflate with the builder's context to ensure the correct style is used.
     LayoutInflater dialogInflater = LayoutInflater.from(builder.getContext());
     View dialogView = dialogInflater.inflate(R.layout.exo_track_selection_dialog, null);
 
-    final TrackSelectionView selectionView = dialogView.findViewById(R.id.exo_track_selection_view);
-    selectionView.init(trackSelector, rendererIndex);
-    Dialog.OnClickListener okClickListener = (dialog, which) -> selectionView.applySelection();
+    TrackSelectionView selectionView = dialogView.findViewById(R.id.exo_track_selection_view);
+    selectionView.init(mappedTrackInfo, rendererIndex, parameters);
+    Dialog.OnClickListener okClickListener =
+        (dialog, which) -> callback.onTracksSelected(selectionView.getSelectionParameters());
 
     AlertDialog dialog =
         builder
@@ -113,6 +153,8 @@ public class TrackSelectionView extends LinearLayout {
     inflater = LayoutInflater.from(context);
     componentListener = new ComponentListener();
     trackNameProvider = new DefaultTrackNameProvider(getResources());
+    parameters = DefaultTrackSelector.Parameters.DEFAULT;
+    trackGroups = TrackGroupArray.EMPTY;
 
     // View for disabling the renderer.
     disableView =
@@ -176,18 +218,35 @@ public class TrackSelectionView extends LinearLayout {
   }
 
   /**
-   * Initialize the view to select tracks for a specified renderer using a {@link
-   * DefaultTrackSelector}.
+   * Initialize the view to select tracks for a specified renderer using {@link MappedTrackInfo} and
+   * a set of {@link DefaultTrackSelector.Parameters}.
    *
-   * @param trackSelector The {@link DefaultTrackSelector}.
+   * @param mappedTrackInfo The {@link MappedTrackInfo}.
    * @param rendererIndex The index of the renderer.
+   * @param parameters The {@link DefaultTrackSelector.Parameters}.
    */
-  public void init(DefaultTrackSelector trackSelector, int rendererIndex) {
-    this.trackSelector = trackSelector;
+  public void init(
+      MappedTrackInfo mappedTrackInfo,
+      int rendererIndex,
+      DefaultTrackSelector.Parameters parameters) {
+    this.mappedTrackInfo = mappedTrackInfo;
     this.rendererIndex = rendererIndex;
+    this.parameters = parameters;
     updateViews();
   }
 
+  /** Returns the {@link DefaultTrackSelector.Parameters} for the current selection. */
+  public DefaultTrackSelector.Parameters getSelectionParameters() {
+    DefaultTrackSelector.ParametersBuilder parametersBuilder = parameters.buildUpon();
+    parametersBuilder.setRendererDisabled(rendererIndex, isDisabled);
+    if (override != null) {
+      parametersBuilder.setSelectionOverride(rendererIndex, trackGroups, override);
+    } else {
+      parametersBuilder.clearSelectionOverrides(rendererIndex);
+    }
+    return parametersBuilder.build();
+  }
+
   // Private methods.
 
   private void updateViews() {
@@ -196,9 +255,7 @@ public class TrackSelectionView extends LinearLayout {
       removeViewAt(i);
     }
 
-    MappingTrackSelector.MappedTrackInfo trackInfo =
-        trackSelector == null ? null : trackSelector.getCurrentMappedTrackInfo();
-    if (trackSelector == null || trackInfo == null) {
+    if (mappedTrackInfo == null) {
       // The view is not initialized.
       disableView.setEnabled(false);
       defaultView.setEnabled(false);
@@ -207,9 +264,8 @@ public class TrackSelectionView extends LinearLayout {
     disableView.setEnabled(true);
     defaultView.setEnabled(true);
 
-    trackGroups = trackInfo.getTrackGroups(rendererIndex);
+    trackGroups = mappedTrackInfo.getTrackGroups(rendererIndex);
 
-    DefaultTrackSelector.Parameters parameters = trackSelector.getParameters();
     isDisabled = parameters.getRendererDisabled(rendererIndex);
     override = parameters.getSelectionOverride(rendererIndex, trackGroups);
 
@@ -220,7 +276,7 @@ public class TrackSelectionView extends LinearLayout {
       boolean enableAdaptiveSelections =
           allowAdaptiveSelections
               && trackGroups.get(groupIndex).length > 1
-              && trackInfo.getAdaptiveSupport(rendererIndex, groupIndex, false)
+              && mappedTrackInfo.getAdaptiveSupport(rendererIndex, groupIndex, false)
                   != RendererCapabilities.ADAPTIVE_NOT_SUPPORTED;
       trackViews[groupIndex] = new CheckedTextView[group.length];
       for (int trackIndex = 0; trackIndex < group.length; trackIndex++) {
@@ -235,7 +291,7 @@ public class TrackSelectionView extends LinearLayout {
             (CheckedTextView) inflater.inflate(trackViewLayoutId, this, false);
         trackView.setBackgroundResource(selectableItemBackgroundResourceId);
         trackView.setText(trackNameProvider.getTrackName(group.getFormat(trackIndex)));
-        if (trackInfo.getTrackSupport(rendererIndex, groupIndex, trackIndex)
+        if (mappedTrackInfo.getTrackSupport(rendererIndex, groupIndex, trackIndex)
             == RendererCapabilities.FORMAT_HANDLED) {
           trackView.setFocusable(true);
           trackView.setTag(Pair.create(groupIndex, trackIndex));
@@ -263,17 +319,6 @@ public class TrackSelectionView extends LinearLayout {
     }
   }
 
-  private void applySelection() {
-    DefaultTrackSelector.ParametersBuilder parametersBuilder = trackSelector.buildUponParameters();
-    parametersBuilder.setRendererDisabled(rendererIndex, isDisabled);
-    if (override != null) {
-      parametersBuilder.setSelectionOverride(rendererIndex, trackGroups, override);
-    } else {
-      parametersBuilder.clearSelectionOverrides(rendererIndex);
-    }
-    trackSelector.setParameters(parametersBuilder);
-  }
-
   private void onClick(View view) {
     if (view == disableView) {
       onDisableViewClicked();

testutils_robolectric/src/main/java/com/google/android/exoplayer2/testutil/FakeTrackSelector.java

@@ -79,8 +79,19 @@ public class FakeTrackSelector extends DefaultTrackSelector {
     }
 
     @Override
-    public TrackSelection createTrackSelection(
-        TrackGroup trackGroup, BandwidthMeter bandwidthMeter, int... tracks) {
+    public TrackSelection[] createTrackSelections(
+        TrackSelection.Definition[] definitions, BandwidthMeter bandwidthMeter) {
+      TrackSelection[] selections = new TrackSelection[definitions.length];
+      for (int i = 0; i < definitions.length; i++) {
+        TrackSelection.Definition definition = definitions[i];
+        if (definition != null) {
+          selections[i] = createTrackSelection(definition.group);
+        }
+      }
+      return selections;
+    }
+
+    private TrackSelection createTrackSelection(TrackGroup trackGroup) {
       if (mayReuseTrackSelection) {
         for (FakeTrackSelection trackSelection : trackSelections) {
           if (trackSelection.getTrackGroup().equals(trackGroup)) {
@@ -92,18 +103,5 @@ public class FakeTrackSelector extends DefaultTrackSelector {
       trackSelections.add(trackSelection);
       return trackSelection;
     }
-
-    @Override
-    public TrackSelection[] createTrackSelections(
-        TrackSelection.Definition[] definitions, BandwidthMeter bandwidthMeter) {
-      TrackSelection[] selections = new TrackSelection[definitions.length];
-      for (int i = 0; i < definitions.length; i++) {
-        TrackSelection.Definition definition = definitions[i];
-        if (definition != null) {
-          selections[i] = createTrackSelection(definition.group, bandwidthMeter, definition.tracks);
-        }
-      }
-      return selections;
-    }
   }
 }

testutils_robolectric/src/main/java/com/google/android/exoplayer2/testutil/TestDownloadManagerListener.java

@@ -17,8 +17,8 @@ package com.google.android.exoplayer2.testutil;
 
 import static com.google.common.truth.Truth.assertThat;
 
-import com.google.android.exoplayer2.offline.DownloadAction;
 import com.google.android.exoplayer2.offline.DownloadManager;
+import com.google.android.exoplayer2.offline.DownloadManager.DownloadState;
 import java.util.HashMap;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.CountDownLatch;
@@ -31,10 +31,10 @@ public final class TestDownloadManagerListener implements DownloadManager.Listen
 
   private final DownloadManager downloadManager;
   private final DummyMainThread dummyMainThread;
-  private final HashMap<DownloadAction, ArrayBlockingQueue<Integer>> actionStates;
+  private final HashMap<String, ArrayBlockingQueue<Integer>> actionStates;
 
   private CountDownLatch downloadFinishedCondition;
-  private Throwable downloadError;
+  @DownloadState.FailureReason private int failureReason;
 
   public TestDownloadManagerListener(
       DownloadManager downloadManager, DummyMainThread dummyMainThread) {
@@ -43,12 +43,12 @@ public final class TestDownloadManagerListener implements DownloadManager.Listen
     actionStates = new HashMap<>();
   }
 
-  public int pollStateChange(DownloadAction action, long timeoutMs) throws InterruptedException {
-    return getStateQueue(action).poll(timeoutMs, TimeUnit.MILLISECONDS);
+  public Integer pollStateChange(String taskId, long timeoutMs) throws InterruptedException {
+    return getStateQueue(taskId).poll(timeoutMs, TimeUnit.MILLISECONDS);
   }
 
   public void clearDownloadError() {
-    this.downloadError = null;
+    this.failureReason = DownloadState.FAILURE_REASON_NONE;
   }
 
   @Override
@@ -57,12 +57,11 @@ public final class TestDownloadManagerListener implements DownloadManager.Listen
   }
 
   @Override
-  public void onTaskStateChanged(
-      DownloadManager downloadManager, DownloadManager.TaskState taskState) {
-    if (taskState.state == DownloadManager.TaskState.STATE_FAILED && downloadError == null) {
-      downloadError = taskState.error;
+  public void onDownloadStateChanged(DownloadManager downloadManager, DownloadState downloadState) {
+    if (downloadState.state == DownloadState.STATE_FAILED) {
+      failureReason = downloadState.failureReason;
     }
-    getStateQueue(taskState.action).add(taskState.state);
+    getStateQueue(downloadState.id).add(downloadState.state);
   }
 
   @Override
@@ -77,6 +76,14 @@ public final class TestDownloadManagerListener implements DownloadManager.Listen
    * error.
    */
   public void blockUntilTasksCompleteAndThrowAnyDownloadError() throws Throwable {
+    blockUntilTasksComplete();
+    if (failureReason != DownloadState.FAILURE_REASON_NONE) {
+      throw new Exception("Failure reason: " + DownloadState.getFailureString(failureReason));
+    }
+  }
+
+  /** Blocks until all remove and download tasks are complete. Task errors are ignored. */
+  public void blockUntilTasksComplete() throws InterruptedException {
     synchronized (this) {
       downloadFinishedCondition = new CountDownLatch(1);
     }
@@ -87,17 +94,14 @@ public final class TestDownloadManagerListener implements DownloadManager.Listen
           }
         });
     assertThat(downloadFinishedCondition.await(TIMEOUT, TimeUnit.MILLISECONDS)).isTrue();
-    if (downloadError != null) {
-      throw new Exception(downloadError);
-    }
   }
 
-  private ArrayBlockingQueue<Integer> getStateQueue(DownloadAction action) {
+  private ArrayBlockingQueue<Integer> getStateQueue(String taskId) {
     synchronized (actionStates) {
-      if (!actionStates.containsKey(action)) {
-        actionStates.put(action, new ArrayBlockingQueue<>(10));
+      if (!actionStates.containsKey(taskId)) {
+        actionStates.put(taskId, new ArrayBlockingQueue<>(10));
       }
-      return actionStates.get(action);
+      return actionStates.get(taskId);
     }
   }
 }