Expose no CC tracks if CLOSED-CAPTIONS=NONE is present

Issue:#2743

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=155182859

library/hls/src/androidTest/java/com/google/android/exoplayer2/source/hls/playlist/HlsMasterPlaylistParserTest.java

@@ -23,6 +23,7 @@ import com.google.android.exoplayer2.util.MimeTypes;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.nio.charset.Charset;
+import java.util.Collections;
 import java.util.List;
 import junit.framework.TestCase;
 
@@ -56,16 +57,22 @@ public class HlsMasterPlaylistParserTest extends TestCase {
 
   private static final String MASTER_PLAYLIST_WITH_CC = " #EXTM3U \n"
       + "#EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS,LANGUAGE=\"es\",NAME=\"Eng\",INSTREAM-ID=\"SERVICE4\"\n"
-      + "\n"
       + "#EXT-X-STREAM-INF:BANDWIDTH=1280000,CODECS=\"mp4a.40.2,avc1.66.30\",RESOLUTION=304x128\n"
       + "http://example.com/low.m3u8\n";
 
+  private static final String MASTER_PLAYLIST_WITHOUT_CC = " #EXTM3U \n"
+      + "#EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS,LANGUAGE=\"es\",NAME=\"Eng\",INSTREAM-ID=\"SERVICE4\"\n"
+      + "#EXT-X-STREAM-INF:BANDWIDTH=1280000,CODECS=\"mp4a.40.2,avc1.66.30\",RESOLUTION=304x128,"
+      + "CLOSED-CAPTIONS=NONE\n"
+      + "http://example.com/low.m3u8\n";
+
   public void testParseMasterPlaylist() throws IOException{
     HlsMasterPlaylist masterPlaylist = parseMasterPlaylist(PLAYLIST_URI, MASTER_PLAYLIST);
 
     List<HlsMasterPlaylist.HlsUrl> variants = masterPlaylist.variants;
     assertNotNull(variants);
     assertEquals(5, variants.size());
+    assertNull(masterPlaylist.muxedCaptionFormats);
 
     assertEquals(1280000, variants.get(0).format.bitrate);
     assertNotNull(variants.get(0).format.codecs);
@@ -117,6 +124,11 @@ public class HlsMasterPlaylistParserTest extends TestCase {
     assertEquals("es", closedCaptionFormat.language);
   }
 
+  public void testPlaylistWithoutClosedCaptions() throws IOException {
+    HlsMasterPlaylist playlist = parseMasterPlaylist(PLAYLIST_URI, MASTER_PLAYLIST_WITHOUT_CC);
+    assertEquals(Collections.emptyList(), playlist.muxedCaptionFormats);
+  }
+
   private static HlsMasterPlaylist parseMasterPlaylist(String uri, String playlistString)
       throws IOException {
     Uri playlistUri = Uri.parse(uri);

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

@@ -111,7 +111,8 @@ import java.util.Locale;
    * @param timestampAdjusterProvider A provider of {@link TimestampAdjuster} instances. If
    *     multiple {@link HlsChunkSource}s are used for a single playback, they should all share the
    *     same provider.
-   * @param muxedCaptionFormats List of muxed caption {@link Format}s.
+   * @param muxedCaptionFormats List of muxed caption {@link Format}s. Null if no closed caption
+   *     information is available in the master playlist.
    */
   public HlsChunkSource(HlsPlaylistTracker playlistTracker, HlsUrl[] variants,
       HlsDataSourceFactory dataSourceFactory, TimestampAdjusterProvider timestampAdjusterProvider,

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

@@ -39,6 +39,7 @@ import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -104,7 +105,8 @@ import java.util.concurrent.atomic.AtomicInteger;
    * @param dataSpec Defines the data to be loaded.
    * @param initDataSpec Defines the initialization data to be fed to new extractors. May be null.
    * @param hlsUrl The url of the playlist from which this chunk was obtained.
-   * @param muxedCaptionFormats List of muxed caption {@link Format}s.
+   * @param muxedCaptionFormats List of muxed caption {@link Format}s. Null if no closed caption
+   *     information is available in the master playlist.
    * @param trackSelectionReason See {@link #trackSelectionReason}.
    * @param trackSelectionData See {@link #trackSelectionData}.
    * @param startTimeUs The start time of the chunk in microseconds.
@@ -356,9 +358,12 @@ import java.util.concurrent.atomic.AtomicInteger;
       // This flag ensures the change of pid between streams does not affect the sample queues.
       @DefaultTsPayloadReaderFactory.Flags
       int esReaderFactoryFlags = DefaultTsPayloadReaderFactory.FLAG_IGNORE_SPLICE_INFO_STREAM;
-      if (!muxedCaptionFormats.isEmpty()) {
+      List<Format> closedCaptionFormats = muxedCaptionFormats;
+      if (closedCaptionFormats != null) {
         // The playlist declares closed caption renditions, we should ignore descriptors.
         esReaderFactoryFlags |= DefaultTsPayloadReaderFactory.FLAG_OVERRIDE_CAPTION_DESCRIPTORS;
+      } else {
+        closedCaptionFormats = Collections.emptyList();
       }
       String codecs = trackFormat.codecs;
       if (!TextUtils.isEmpty(codecs)) {
@@ -373,7 +378,7 @@ import java.util.concurrent.atomic.AtomicInteger;
         }
       }
       extractor = new TsExtractor(TsExtractor.MODE_HLS, timestampAdjuster,
-          new DefaultTsPayloadReaderFactory(esReaderFactoryFlags, muxedCaptionFormats));
+          new DefaultTsPayloadReaderFactory(esReaderFactoryFlags, closedCaptionFormats));
     }
     if (usingNewExtractor) {
       extractor.init(extractorOutput);

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

@@ -30,15 +30,31 @@ public final class HlsMasterPlaylist extends HlsPlaylist {
    */
   public static final class HlsUrl {
 
+    /**
+     * The http url from which the media playlist can be obtained.
+     */
     public final String url;
+    /**
+     * Format information associated with the HLS url.
+     */
     public final Format format;
 
-    public static HlsUrl createMediaPlaylistHlsUrl(String baseUri) {
+    /**
+     * Creates an HLS url from a given http url.
+     *
+     * @param url The url.
+     * @return An HLS url.
+     */
+    public static HlsUrl createMediaPlaylistHlsUrl(String url) {
       Format format = Format.createContainerFormat("0", MimeTypes.APPLICATION_M3U8, null, null,
           Format.NO_VALUE, 0, null);
-      return new HlsUrl(baseUri, format);
+      return new HlsUrl(url, format);
     }
 
+    /**
+     * @param url See {@link #url}.
+     * @param format See {@link #format}.
+     */
     public HlsUrl(String url, Format format) {
       this.url = url;
       this.format = format;
@@ -46,13 +62,39 @@ public final class HlsMasterPlaylist extends HlsPlaylist {
 
   }
 
+  /**
+   * The list of variants declared by the playlist.
+   */
   public final List<HlsUrl> variants;
+  /**
+   * The list of demuxed audios declared by the playlist.
+   */
   public final List<HlsUrl> audios;
+  /**
+   * The list of subtitles declared by the playlist.
+   */
   public final List<HlsUrl> subtitles;
 
+  /**
+   * The format of the audio muxed in the variants. May be null if the playlist does not declare any
+   * muxed audio.
+   */
   public final Format muxedAudioFormat;
+  /**
+   * The format of the closed captions declared by the playlist. May be empty if the playlist
+   * explicitly declares no captions are available, or null if the playlist does not declare any
+   * captions information.
+   */
   public final List<Format> muxedCaptionFormats;
 
+  /**
+   * @param baseUri The base uri. Used to resolve relative paths.
+   * @param variants See {@link #variants}.
+   * @param audios See {@link #audios}.
+   * @param subtitles See {@link #subtitles}.
+   * @param muxedAudioFormat See {@link #muxedAudioFormat}.
+   * @param muxedCaptionFormats See {@link #muxedCaptionFormats}.
+   */
   public HlsMasterPlaylist(String baseUri, List<HlsUrl> variants, List<HlsUrl> audios,
       List<HlsUrl> subtitles, Format muxedAudioFormat, List<Format> muxedCaptionFormats) {
     super(baseUri);
@@ -60,14 +102,20 @@ public final class HlsMasterPlaylist extends HlsPlaylist {
     this.audios = Collections.unmodifiableList(audios);
     this.subtitles = Collections.unmodifiableList(subtitles);
     this.muxedAudioFormat = muxedAudioFormat;
-    this.muxedCaptionFormats = Collections.unmodifiableList(muxedCaptionFormats);
+    this.muxedCaptionFormats = muxedCaptionFormats != null
+        ? Collections.unmodifiableList(muxedCaptionFormats) : null;
   }
 
-  public static HlsMasterPlaylist createSingleVariantMasterPlaylist(String variantUri) {
+  /**
-    List<HlsUrl> variant = Collections.singletonList(HlsUrl.createMediaPlaylistHlsUrl(variantUri));
+   * Creates a playlist with a single variant.
+   *
+   * @param variantUrl The url of the single variant.
+   * @return A master playlist with a single variant for the provided url.
+   */
+  public static HlsMasterPlaylist createSingleVariantMasterPlaylist(String variantUrl) {
+    List<HlsUrl> variant = Collections.singletonList(HlsUrl.createMediaPlaylistHlsUrl(variantUrl));
     List<HlsUrl> emptyList = Collections.emptyList();
-    return new HlsMasterPlaylist(null, variant, emptyList, emptyList, null,
+    return new HlsMasterPlaylist(null, variant, emptyList, emptyList, null, null);
-        Collections.<Format>emptyList());
   }
 
 }

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

@@ -29,6 +29,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
@@ -70,6 +71,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final String BOOLEAN_TRUE = "YES";
   private static final String BOOLEAN_FALSE = "NO";
 
+  private static final String ATTR_CLOSED_CAPTIONS_NONE = "CLOSED-CAPTIONS=NONE";
+
   private static final Pattern REGEX_BANDWIDTH = Pattern.compile("BANDWIDTH=(\\d+)\\b");
   private static final Pattern REGEX_CODECS = Pattern.compile("CODECS=\"(.+?)\"");
   private static final Pattern REGEX_RESOLUTION = Pattern.compile("RESOLUTION=(\\d+x\\d+)");
@@ -173,7 +176,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     ArrayList<HlsMasterPlaylist.HlsUrl> audios = new ArrayList<>();
     ArrayList<HlsMasterPlaylist.HlsUrl> subtitles = new ArrayList<>();
     Format muxedAudioFormat = null;
-    ArrayList<Format> muxedCaptionFormats = new ArrayList<>();
+    List<Format> muxedCaptionFormats = null;
+    boolean noClosedCaptions = false;
 
     String line;
     while (iterator.hasNext()) {
@@ -210,6 +214,9 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
               mimeType = MimeTypes.APPLICATION_CEA708;
               accessibilityChannel = Integer.parseInt(instreamId.substring(7));
             }
+            if (muxedCaptionFormats == null) {
+              muxedCaptionFormats = new ArrayList<>();
+            }
             muxedCaptionFormats.add(Format.createTextContainerFormat(id, null, mimeType, null,
                 Format.NO_VALUE, selectionFlags, language, accessibilityChannel));
             break;
@@ -221,6 +228,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
         int bitrate = parseIntAttr(line, REGEX_BANDWIDTH);
         String codecs = parseOptionalStringAttr(line, REGEX_CODECS);
         String resolutionString = parseOptionalStringAttr(line, REGEX_RESOLUTION);
+        noClosedCaptions |= line.contains(ATTR_CLOSED_CAPTIONS_NONE);
         int width;
         int height;
         if (resolutionString != null) {
@@ -243,6 +251,9 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
         variants.add(new HlsMasterPlaylist.HlsUrl(line, format));
       }
     }
+    if (noClosedCaptions) {
+      muxedCaptionFormats = Collections.emptyList();
+    }
     return new HlsMasterPlaylist(baseUri, variants, audios, subtitles, muxedAudioFormat,
         muxedCaptionFormats);
   }