Allow enabling of EMSG/608 outputs on DefaultDashChunkSource

Issue #2176

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148027655

library/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java

@@ -1085,7 +1085,6 @@ public final class FragmentedMp4Extractor implements Extractor {
           output.sampleData(nalStartCode, 4);
           // Write the NAL unit type byte.
           output.sampleData(nalPrefix, 1);
-          // TODO: Don't try and process the SEI NAL unit if the payload is encrypted.
           processSeiNalUnitPayload = cea608TrackOutput != null
               && NalUnitUtil.isNalUnitSei(track.format.sampleMimeType, nalPrefixData[4]);
           sampleBytesWritten += 5;

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

@@ -29,7 +29,8 @@ public interface DashChunkSource extends ChunkSource {
 
     DashChunkSource createDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
         DashManifest manifest, int periodIndex, int adaptationSetIndex,
-        TrackSelection trackSelection, long elapsedRealtimeOffsetMs);
+        TrackSelection trackSelection, long elapsedRealtimeOffsetMs,
+        boolean enableEventMessageTrack, boolean enableCea608Track);
 
   }
 

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

@@ -203,7 +203,7 @@ import java.util.List;
     AdaptationSet adaptationSet = period.adaptationSets.get(adaptationSetIndex);
     DashChunkSource chunkSource = chunkSourceFactory.createDashChunkSource(
         manifestLoaderErrorThrower, manifest, index, adaptationSetIndex, selection,
-        elapsedRealtimeOffset);
+        elapsedRealtimeOffset, false, false);
     return new ChunkSampleStream<>(adaptationSet.type, chunkSource, this, allocator, positionUs,
         minLoadableRetryCount, eventDispatcher);
   }

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

@@ -70,11 +70,12 @@ public class DefaultDashChunkSource implements DashChunkSource {
     @Override
     public DashChunkSource createDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
         DashManifest manifest, int periodIndex, int adaptationSetIndex,
-        TrackSelection trackSelection, long elapsedRealtimeOffsetMs) {
+        TrackSelection trackSelection, long elapsedRealtimeOffsetMs,
+        boolean enableEventMessageTrack, boolean enableCea608Track) {
       DataSource dataSource = dataSourceFactory.createDataSource();
       return new DefaultDashChunkSource(manifestLoaderErrorThrower, manifest, periodIndex,
           adaptationSetIndex, trackSelection, dataSource, elapsedRealtimeOffsetMs,
-          maxSegmentsPerLoad);
+          maxSegmentsPerLoad, enableEventMessageTrack, enableCea608Track);
     }
 
   }
@@ -106,10 +107,15 @@ public class DefaultDashChunkSource implements DashChunkSource {
    * @param maxSegmentsPerLoad The maximum number of segments to combine into a single request.
    *     Note that segments will only be combined if their {@link Uri}s are the same and if their
    *     data ranges are adjacent.
+   * @param enableEventMessageTrack Whether the chunks generated by the source may output an event
+   *     message track.
+   * @param enableEventMessageTrack Whether the chunks generated by the source may output a CEA-608
+   *     track.
    */
   public DefaultDashChunkSource(LoaderErrorThrower manifestLoaderErrorThrower,
       DashManifest manifest, int periodIndex, int adaptationSetIndex, TrackSelection trackSelection,
-      DataSource dataSource, long elapsedRealtimeOffsetMs, int maxSegmentsPerLoad) {
+      DataSource dataSource, long elapsedRealtimeOffsetMs, int maxSegmentsPerLoad,
+      boolean enableEventMessageTrack, boolean enableCea608Track) {
     this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
     this.manifest = manifest;
     this.adaptationSetIndex = adaptationSetIndex;
@@ -126,7 +132,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
     for (int i = 0; i < representationHolders.length; i++) {
       Representation representation = representations.get(trackSelection.getIndexInTrackGroup(i));
       representationHolders[i] = new RepresentationHolder(periodDurationUs, representation,
-          adaptationSet.type);
+          enableEventMessageTrack, enableCea608Track, adaptationSet.type);
     }
   }
 
@@ -364,7 +370,6 @@ public class DefaultDashChunkSource implements DashChunkSource {
 
   protected static final class RepresentationHolder {
 
-    public final int trackType;
     public final ChunkExtractorWrapper extractorWrapper;
 
     public Representation representation;
@@ -374,10 +379,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
     private int segmentNumShift;
 
     public RepresentationHolder(long periodDurationUs, Representation representation,
-        int trackType) {
+        boolean enableEventMessageTrack, boolean enableCea608Track, int trackType) {
       this.periodDurationUs = periodDurationUs;
       this.representation = representation;
-      this.trackType = trackType;
       String containerMimeType = representation.format.containerMimeType;
       if (mimeTypeIsRawText(containerMimeType)) {
         extractorWrapper = null;
@@ -388,8 +392,14 @@ public class DefaultDashChunkSource implements DashChunkSource {
         } else if (mimeTypeIsWebm(containerMimeType)) {
           extractor = new MatroskaExtractor();
         } else {
-          extractor = new FragmentedMp4Extractor(FragmentedMp4Extractor.FLAG_ENABLE_CEA608_TRACK
-              | FragmentedMp4Extractor.FLAG_ENABLE_EMSG_TRACK);
+          int flags = 0;
+          if (enableEventMessageTrack) {
+            flags |= FragmentedMp4Extractor.FLAG_ENABLE_EMSG_TRACK;
+          }
+          if (enableCea608Track) {
+            flags |= FragmentedMp4Extractor.FLAG_ENABLE_CEA608_TRACK;
+          }
+          extractor = new FragmentedMp4Extractor(flags);
         }
         // Prefer drmInitData obtained from the manifest over drmInitData obtained from the stream,
         // as per DASH IF Interoperability Recommendations V3.0, 7.5.3.