Propagate resets at the source rather than track level.

- Code is simpler. We only ever reset all tracks.
- Allows the standalone media clock to be updated properly. This
  allows simpler recovery for live streams in ExtractorSampleSource.
- Fixes #1285 and paves the way for a fix for #758.

Issue: #1285
Issue: #758
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120530682

library/src/main/java/com/google/android/exoplayer/ExoPlayerImplInternal.java

@@ -356,14 +356,12 @@ import java.util.concurrent.atomic.AtomicInteger;
 
     TraceUtil.beginSection("doSomeWork");
 
-    // Process resets.
-    for (TrackRenderer renderer : enabledRenderers) {
-      renderer.checkForReset();
-    }
-
-    updatePositionUs();
-    updateBufferedPositionUs();
     if (enabledRenderers.length > 0) {
+      // Process reset if there is one, else update the position.
+      if (!checkForSourceResetInternal()) {
+        updatePositionUs();
+      }
+      updateBufferedPositionUs();
       source.continueBuffering(positionUs);
     }
 
@@ -435,14 +433,12 @@ import java.util.concurrent.atomic.AtomicInteger;
         return;
       }
 
-      if (enabledRenderers != null) {
+      if (enabledRenderers.length > 0) {
         for (TrackRenderer renderer : enabledRenderers) {
           ensureStopped(renderer);
         }
         source.seekToUs(positionUs);
-        for (TrackRenderer renderer : enabledRenderers) {
-          renderer.checkForReset();
-        }
+        checkForSourceResetInternal();
       }
 
       resumeInternal();
@@ -474,6 +470,19 @@ import java.util.concurrent.atomic.AtomicInteger;
     handler.sendEmptyMessage(MSG_DO_SOME_WORK);
   }
 
+  private boolean checkForSourceResetInternal() throws ExoPlaybackException {
+    long resetPositionUs = source.readReset();
+    if (resetPositionUs == C.UNSET_TIME_US) {
+      return false;
+    }
+    positionUs = resetPositionUs;
+    standaloneMediaClock.setPositionUs(resetPositionUs);
+    for (TrackRenderer renderer : enabledRenderers) {
+      renderer.reset(resetPositionUs);
+    }
+    return true;
+  }
+
   private void stopInternal() {
     resetInternal();
     setState(ExoPlayer.STATE_IDLE);

library/src/main/java/com/google/android/exoplayer/FrameworkSampleSource.java

@@ -73,11 +73,11 @@ public final class FrameworkSampleSource implements SampleSource {
   private final long fileDescriptorLength;
 
   private boolean prepared;
+  private boolean notifyReset;
   private long durationUs;
   private MediaExtractor extractor;
   private TrackGroupArray tracks;
   private int[] trackStates;
-  private boolean[] pendingResets;
 
   private int enabledTrackCount;
   private long lastSeekPositionUs;
@@ -135,7 +135,6 @@ public final class FrameworkSampleSource implements SampleSource {
       extractor.setDataSource(fileDescriptor, fileDescriptorOffset, fileDescriptorLength);
     }
     trackStates = new int[extractor.getTrackCount()];
-    pendingResets = new boolean[trackStates.length];
     TrackGroup[] trackArray = new TrackGroup[trackStates.length];
     for (int i = 0; i < trackStates.length; i++) {
       MediaFormat format = extractor.getTrackFormat(i);
@@ -170,7 +169,6 @@ public final class FrameworkSampleSource implements SampleSource {
       enabledTrackCount--;
       trackStates[track] = TRACK_STATE_DISABLED;
       extractor.unselectTrack(track);
-      pendingResets[track] = false;
     }
     // Select new tracks.
     TrackStream[] newStreams = new TrackStream[newSelections.size()];
@@ -197,6 +195,15 @@ public final class FrameworkSampleSource implements SampleSource {
      // MediaExtractor takes care of buffering. Do nothing.
   }
 
+  @Override
+  public long readReset() {
+    if (notifyReset) {
+      notifyReset = false;
+      return lastSeekPositionUs;
+    }
+    return C.UNSET_TIME_US;
+  }
+
   @Override
   public void seekToUs(long positionUs) {
     if (enabledTrackCount == 0) {
@@ -230,17 +237,9 @@ public final class FrameworkSampleSource implements SampleSource {
 
   // TrackStream methods.
 
-  /* package */ long readReset(int track) {
-    if (pendingResets[track]) {
-      pendingResets[track] = false;
-      return lastSeekPositionUs;
-    }
-    return C.UNSET_TIME_US;
-  }
-
   /* package */ int readData(int track, FormatHolder formatHolder, DecoderInputBuffer buffer) {
     Assertions.checkState(trackStates[track] != TRACK_STATE_DISABLED);
-    if (pendingResets[track]) {
+    if (notifyReset) {
       return TrackStream.NOTHING_READ;
     }
     if (trackStates[track] != TRACK_STATE_FORMAT_SENT) {
@@ -302,11 +301,7 @@ public final class FrameworkSampleSource implements SampleSource {
       lastSeekPositionUs = positionUs;
       pendingSeekPositionUs = positionUs;
       extractor.seekTo(positionUs, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
-      for (int i = 0; i < trackStates.length; ++i) {
-        if (trackStates[i] != TRACK_STATE_DISABLED) {
-          pendingResets[i] = true;
-        }
-      }
+      notifyReset = true;
     }
   }
 
@@ -382,11 +377,6 @@ public final class FrameworkSampleSource implements SampleSource {
       // Do nothing.
     }
 
-    @Override
-    public long readReset() {
-      return FrameworkSampleSource.this.readReset(track);
-    }
-
     @Override
     public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
       return FrameworkSampleSource.this.readData(track, formatHolder, buffer);

library/src/main/java/com/google/android/exoplayer/MultiSampleSource.java

@@ -123,6 +123,20 @@ public final class MultiSampleSource implements SampleSource {
     }
   }
 
+  @Override
+  public long readReset() {
+    long resetPositionUs = C.UNSET_TIME_US;
+    for (SampleSource source : enabledSources) {
+      long childResetPositionUs = source.readReset();
+      if (resetPositionUs == C.UNSET_TIME_US) {
+        resetPositionUs = childResetPositionUs;
+      } else if (childResetPositionUs != C.UNSET_TIME_US) {
+        resetPositionUs = Math.min(resetPositionUs, childResetPositionUs);
+      }
+    }
+    return resetPositionUs;
+  }
+
   @Override
   public long getBufferedPositionUs() {
     long bufferedPositionUs = durationUs != C.UNSET_TIME_US ? durationUs : Long.MAX_VALUE;

library/src/main/java/com/google/android/exoplayer/SampleSource.java

@@ -84,6 +84,14 @@ public interface SampleSource {
    */
   void continueBuffering(long positionUs);
 
+  /**
+   * Attempts to read a pending reset.
+   *
+   * @return If a reset was read then the playback position in microseconds after the reset. Else
+   *     {@link C#UNSET_TIME_US}.
+   */
+  long readReset();
+
   /**
    * Returns an estimate of the position up to which data is buffered for the enabled tracks.
    * <p>

library/src/main/java/com/google/android/exoplayer/TrackRenderer.java

@@ -215,21 +215,6 @@ public abstract class TrackRenderer implements ExoPlayerComponent {
     // Do nothing.
   }
 
-  /**
-   * Attempts to read and process a pending reset from the {@link TrackStream}.
-   * <p>
-   * This method may be called when the renderer is in the following states:
-   * {@link #STATE_ENABLED}, {@link #STATE_STARTED}.
-   *
-   * @throws ExoPlaybackException If an error occurs.
-   */
-  /* package */ final void checkForReset() throws ExoPlaybackException {
-    long resetPositionUs = stream.readReset();
-    if (resetPositionUs != C.UNSET_TIME_US) {
-      reset(resetPositionUs);
-    }
-  }
-
   /**
    * Stops the renderer.
    *

library/src/main/java/com/google/android/exoplayer/TrackStream.java

@@ -53,19 +53,8 @@ public interface TrackStream {
    */
   void maybeThrowError() throws IOException;
 
-  /**
-   * Attempts to read a pending reset.
-   *
-   * @return If a reset was read then the playback position in microseconds after the reset. Else
-   *     {@link C#UNSET_TIME_US}.
-   */
-  long readReset();
-
   /**
    * Attempts to read from the stream.
-   * <p>
-   * This method will always return {@link #NOTHING_READ} in the case that there's a pending
-   * discontinuity to be read from {@link #readReset} for the specified track.
    *
    * @param formatHolder A {@link FormatHolder} to populate in the case of reading a format.
    * @param buffer A {@link DecoderInputBuffer} to populate in the case of reading a sample or the

library/src/main/java/com/google/android/exoplayer/extractor/ExtractorSampleSource.java

@@ -207,22 +207,18 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
 
   private boolean prepared;
   private boolean seenFirstTrackSelection;
+  private boolean notifyReset;
   private int enabledTrackCount;
   private DefaultTrackOutput[] sampleQueues;
   private TrackGroupArray tracks;
   private long durationUs;
   private boolean[] pendingMediaFormat;
-  private boolean[] pendingResets;
   private boolean[] trackEnabledStates;
 
   private long downstreamPositionUs;
   private long lastSeekPositionUs;
   private long pendingResetPositionUs;
 
-  private boolean havePendingNextSampleUs;
-  private long pendingNextSampleUs;
-  private long sampleTimeOffsetUs;
-
   private ExtractingLoadable loadable;
   private IOException fatalException;
   private int extractedSamplesCountAtStartOfLoad;
@@ -336,7 +332,6 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       int trackCount = sampleQueues.length;
       TrackGroup[] trackArray = new TrackGroup[trackCount];
       trackEnabledStates = new boolean[trackCount];
-      pendingResets = new boolean[trackCount];
       pendingMediaFormat = new boolean[trackCount];
       durationUs = seekMap.getDurationUs();
       for (int i = 0; i < trackCount; i++) {
@@ -390,7 +385,6 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       enabledTrackCount++;
       trackEnabledStates[track] = true;
       pendingMediaFormat[track] = true;
-      pendingResets[track] = false;
       newStreams[i] = new TrackStreamImpl(track);
     }
     // Cancel or start requests as necessary.
@@ -415,6 +409,15 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
     discardSamplesForDisabledTracks();
   }
 
+  @Override
+  public long readReset() {
+    if (notifyReset) {
+      notifyReset = false;
+      return lastSeekPositionUs;
+    }
+    return C.UNSET_TIME_US;
+  }
+
   @Override
   public long getBufferedPositionUs() {
     if (loadingFinished) {
@@ -458,16 +461,8 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
     loader.maybeThrowError();
   }
 
-  /* package */ long readReset(int track) {
-    if (pendingResets[track]) {
-      pendingResets[track] = false;
-      return lastSeekPositionUs;
-    }
-    return C.UNSET_TIME_US;
-  }
-
   /* package */ int readData(int track, FormatHolder formatHolder, DecoderInputBuffer buffer) {
-    if (pendingResets[track] || isPendingReset()) {
+    if (notifyReset || isPendingReset()) {
       return TrackStream.NOTHING_READ;
     }
 
@@ -483,12 +478,6 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       if (buffer.timeUs < lastSeekPositionUs) {
         buffer.addFlag(C.BUFFER_FLAG_DECODE_ONLY);
       }
-      if (havePendingNextSampleUs) {
-        // Set the offset to make the timestamp of this sample equal to pendingNextSampleUs.
-        sampleTimeOffsetUs = pendingNextSampleUs - buffer.timeUs;
-        havePendingNextSampleUs = false;
-      }
-      buffer.timeUs += sampleTimeOffsetUs;
       return TrackStream.BUFFER_READ;
     }
 
@@ -524,10 +513,10 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       fatalException = e;
       return Loader.DONT_RETRY;
     }
-    configureRetry();
     int extractedSamplesCount = getExtractedSamplesCount();
     boolean madeProgress = extractedSamplesCount > extractedSamplesCountAtStartOfLoad;
-    extractedSamplesCountAtStartOfLoad = extractedSamplesCount;
+    configureRetry(); // May clear the sample queues.
+    extractedSamplesCountAtStartOfLoad = getExtractedSamplesCount();
     return madeProgress ? Loader.RETRY_RESET_ERROR_COUNT : Loader.RETRY;
   }
 
@@ -563,7 +552,7 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
     positionUs = seekMap.isSeekable() ? positionUs : 0;
     lastSeekPositionUs = positionUs;
     downstreamPositionUs = positionUs;
-    Arrays.fill(pendingResets, true);
+    notifyReset = true;
     // If we're not pending a reset, see if we can seek within the sample queues.
     boolean seekInsideBuffer = !isPendingReset();
     for (int i = 0; seekInsideBuffer && i < sampleQueues.length; i++) {
@@ -589,8 +578,6 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
   }
 
   private void startLoading() {
-    sampleTimeOffsetUs = 0;
-    havePendingNextSampleUs = false;
     loadable = new ExtractingLoadable(uri, dataSource, extractorHolder, allocator,
         requestedBufferSize);
     if (prepared) {
@@ -620,12 +607,9 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       // therefore that the data at the uri is a continuously shifting window of the latest
       // available media. For this case there's no way to continue loading from where a previous
       // load finished, so it's necessary to load from the start whenever commencing a new load.
+      notifyReset = true;
       clearSampleQueues();
       loadable.setLoadPosition(0);
-      // To avoid introducing a discontinuity, we shift the sample timestamps so that they will
-      // continue from the current downstream position.
-      pendingNextSampleUs = downstreamPositionUs;
-      havePendingNextSampleUs = true;
     } else {
       // We're playing a seekable on-demand stream. Resume the current loadable, which will
       // request data starting from the point it left off.
@@ -706,11 +690,6 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
       ExtractorSampleSource.this.maybeThrowError();
     }
 
-    @Override
-    public long readReset() {
-      return ExtractorSampleSource.this.readReset(track);
-    }
-
     @Override
     public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
       return ExtractorSampleSource.this.readData(track, formatHolder, buffer);

library/src/main/java/com/google/android/exoplayer/hls/HlsSampleSource.java

@@ -39,7 +39,6 @@ import android.os.Handler;
 import android.os.SystemClock;
 
 import java.io.IOException;
-import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -69,6 +68,7 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
 
   private boolean prepared;
   private boolean seenFirstTrackSelection;
+  private boolean notifyReset;
   private int enabledTrackCount;
   private DefaultTrackOutput[] sampleQueues;
   private Format downstreamFormat;
@@ -79,7 +79,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
   private int primaryTrackGroupIndex;
   // Indexed by group.
   private boolean[] groupEnabledStates;
-  private boolean[] pendingResets;
   private Format[] downstreamSampleFormats;
 
   private long downstreamPositionUs;
@@ -204,7 +203,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
       int[] tracks = selection.getTracks();
       setTrackGroupEnabledState(group, true);
       downstreamSampleFormats[group] = null;
-      pendingResets[group] = false;
       if (group == primaryTrackGroupIndex) {
         primaryTracksDeselected |= chunkSource.selectTracks(tracks);
       }
@@ -245,6 +243,15 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     }
   }
 
+  @Override
+  public long readReset() {
+    if (notifyReset) {
+      notifyReset = false;
+      return lastSeekPositionUs;
+    }
+    return C.UNSET_TIME_US;
+  }
+
   @Override
   public long getBufferedPositionUs() {
     if (loadingFinished) {
@@ -293,16 +300,8 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     chunkSource.maybeThrowError();
   }
 
-  /* package */ long readReset(int group) {
-    if (pendingResets[group]) {
-      pendingResets[group] = false;
-      return lastSeekPositionUs;
-    }
-    return C.UNSET_TIME_US;
-  }
-
   /* package */ int readData(int group, FormatHolder formatHolder, DecoderInputBuffer buffer) {
-    if (pendingResets[group] || isPendingReset()) {
+    if (notifyReset || isPendingReset()) {
       return TrackStream.NOTHING_READ;
     }
 
@@ -464,7 +463,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     // Instantiate the necessary internal data-structures.
     primaryTrackGroupIndex = -1;
     groupEnabledStates = new boolean[extractorTrackCount];
-    pendingResets = new boolean[extractorTrackCount];
     downstreamSampleFormats = new Format[extractorTrackCount];
 
     // Construct the set of exposed track groups.
@@ -531,7 +529,7 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     positionUs = chunkSource.isLive() ? 0 : positionUs;
     lastSeekPositionUs = positionUs;
     downstreamPositionUs = positionUs;
-    Arrays.fill(pendingResets, true);
+    notifyReset = true;
     boolean seekInsideBuffer = !isPendingReset();
     // TODO[REFACTOR]: This will nearly always fail to seek inside all buffers due to sparse tracks
     // such as ID3 (probably EIA608 too). We need a way to not care if we can't seek to the keyframe
@@ -670,11 +668,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
       HlsSampleSource.this.maybeThrowError();
     }
 
-    @Override
-    public long readReset() {
-      return HlsSampleSource.this.readReset(group);
-    }
-
     @Override
     public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
       return HlsSampleSource.this.readData(group, formatHolder, buffer);