Support multiple CC channels in DASH

Issue: #5656
PiperOrigin-RevId: 241235377

RELEASENOTES.md

@@ -5,7 +5,10 @@
 * Update to Mockito 2
 * Add new `ExoPlaybackException` types for remote exceptions and out-of-memory
   errors.
-* DASH: Parse role and accessibility descriptors into `Format.roleFlags`.
+* DASH:
+  * Parse role and accessibility descriptors into `Format.roleFlags`.
+  * Support multiple CEA-608 channels muxed into FMP4 representations
+    ([#5656](https://github.com/google/ExoPlayer/issues/5656)).
 * HLS:
   * Work around lack of LA_URL attribute in PlayReady key request init data.
   * Prevent unnecessary reloads of initialization segments.

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

@@ -17,12 +17,14 @@ package com.google.android.exoplayer2.source.dash;
 
 import android.os.SystemClock;
 import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.chunk.ChunkSource;
 import com.google.android.exoplayer2.source.dash.PlayerEmsgHandler.PlayerTrackEmsgHandler;
 import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.upstream.LoaderErrorThrower;
 import com.google.android.exoplayer2.upstream.TransferListener;
+import java.util.List;
 
 /**
  * An {@link ChunkSource} for DASH streams.
@@ -41,10 +43,8 @@ public interface DashChunkSource extends ChunkSource {
      * @param elapsedRealtimeOffsetMs If known, an estimate of the instantaneous difference between
      *     server-side unix time and {@link SystemClock#elapsedRealtime()} in milliseconds,
      *     specified as the server's unix time minus the local elapsed time. If unknown, set to 0.
-     * @param enableEventMessageTrack Whether the chunks generated by the source may output an event
-     *     message track.
-     * @param enableCea608Track Whether the chunks generated by the source may output a CEA-608
-     *     track.
+     * @param enableEventMessageTrack Whether to output an event message track.
+     * @param closedCaptionFormats The {@link Format Formats} of closed caption tracks to be output.
      * @param transferListener The transfer listener which should be informed of any data transfers.
      *     May be null if no listener is available.
      * @return The created {@link DashChunkSource}.
@@ -58,7 +58,7 @@ public interface DashChunkSource extends ChunkSource {
         int type,
         long elapsedRealtimeOffsetMs,
         boolean enableEventMessageTrack,
-        boolean enableCea608Track,
+        List<Format> closedCaptionFormats,
         @Nullable PlayerTrackEmsgHandler playerEmsgHandler,
         @Nullable TransferListener transferListener);
   }

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

@@ -54,7 +54,6 @@ import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 /**
@@ -86,7 +85,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
         int trackType,
         long elapsedRealtimeOffsetMs,
         boolean enableEventMessageTrack,
-        boolean enableCea608Track,
+        List<Format> closedCaptionFormats,
         @Nullable PlayerTrackEmsgHandler playerEmsgHandler,
         @Nullable TransferListener transferListener) {
       DataSource dataSource = dataSourceFactory.createDataSource();
@@ -104,7 +103,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
           elapsedRealtimeOffsetMs,
           maxSegmentsPerLoad,
           enableEventMessageTrack,
-          enableCea608Track,
+          closedCaptionFormats,
           playerEmsgHandler);
     }
 
@@ -141,9 +140,8 @@ 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 enableCea608Track Whether the chunks generated by the source may output a CEA-608 track.
+   * @param enableEventMessageTrack Whether to output an event message track.
+   * @param closedCaptionFormats The {@link Format Formats} of closed caption tracks to be output.
    * @param playerTrackEmsgHandler The {@link PlayerTrackEmsgHandler} instance to handle emsg
    *     messages targeting the player. Maybe null if this is not necessary.
    */
@@ -158,7 +156,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
       long elapsedRealtimeOffsetMs,
       int maxSegmentsPerLoad,
       boolean enableEventMessageTrack,
-      boolean enableCea608Track,
+      List<Format> closedCaptionFormats,
       @Nullable PlayerTrackEmsgHandler playerTrackEmsgHandler) {
     this.manifestLoaderErrorThrower = manifestLoaderErrorThrower;
     this.manifest = manifest;
@@ -184,7 +182,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
               trackType,
               representation,
               enableEventMessageTrack,
-              enableCea608Track,
+              closedCaptionFormats,
               playerTrackEmsgHandler);
     }
   }
@@ -629,7 +627,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
         int trackType,
         Representation representation,
         boolean enableEventMessageTrack,
-        boolean enableCea608Track,
+        List<Format> closedCaptionFormats,
         TrackOutput playerEmsgTrackOutput) {
       this(
           periodDurationUs,
@@ -638,7 +636,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
               trackType,
               representation,
               enableEventMessageTrack,
-              enableCea608Track,
+              closedCaptionFormats,
               playerEmsgTrackOutput),
           /* segmentNumShift= */ 0,
           representation.getIndex());
@@ -783,7 +781,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
         int trackType,
         Representation representation,
         boolean enableEventMessageTrack,
-        boolean enableCea608Track,
+        List<Format> closedCaptionFormats,
         TrackOutput playerEmsgTrackOutput) {
       String containerMimeType = representation.format.containerMimeType;
       if (mimeTypeIsRawText(containerMimeType)) {
@@ -799,12 +797,6 @@ public class DefaultDashChunkSource implements DashChunkSource {
         if (enableEventMessageTrack) {
           flags |= FragmentedMp4Extractor.FLAG_ENABLE_EMSG_TRACK;
         }
-        // TODO: Use caption format information from the manifest if available.
-        List<Format> closedCaptionFormats =
-            enableCea608Track
-                ? Collections.singletonList(
-                    Format.createTextSampleFormat(null, MimeTypes.APPLICATION_CEA608, 0, null))
-                : Collections.emptyList();
         extractor =
             new FragmentedMp4Extractor(
                 flags, null, null, null, closedCaptionFormats, playerEmsgTrackOutput);