Force single audio and video sample queues

This solves the problem of having dense tracks' ids change.
For example, if the available variants offer both HEVC and AVC video
tracks, all video samples will map to the same sample queue even if
IDs don't match.

Issue:#3653

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=182070486

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

@@ -156,7 +156,7 @@ public HlsMediaChunk(HlsExtractorFactory extractorFactory, DataSource dataSource
    */
   public void init(HlsSampleStreamWrapper output) {
     this.output = output;
-    output.init(uid, shouldSpliceIn);
+    output.init(uid, shouldSpliceIn, reusingExtractor);
     if (!reusingExtractor) {
       extractor.init(output);
     }

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

@@ -93,6 +93,10 @@ public interface Callback extends SequenceableLoader.Callback<HlsSampleStreamWra
 
   private SampleQueue[] sampleQueues;
   private int[] sampleQueueTrackIds;
+  private boolean audioSampleQueueMappingDone;
+  private int audioSampleQueueIndex;
+  private boolean videoSampleQueueMappingDone;
+  private int videoSampleQueueIndex;
   private boolean sampleQueuesBuilt;
   private boolean prepared;
   private int enabledTrackGroupCount;
@@ -143,6 +147,8 @@ public HlsSampleStreamWrapper(int trackType, Callback callback, HlsChunkSource c
     loader = new Loader("Loader:HlsSampleStreamWrapper");
     nextChunkHolder = new HlsChunkSource.HlsChunkHolder();
     sampleQueueTrackIds = new int[0];
+    audioSampleQueueIndex = C.INDEX_UNSET;
+    videoSampleQueueIndex = C.INDEX_UNSET;
     sampleQueues = new SampleQueue[0];
     sampleQueueIsAudioVideoFlags = new boolean[0];
     sampleQueuesEnabledStates = new boolean[0];
@@ -616,8 +622,14 @@ public int onLoadError(Chunk loadable, long elapsedRealtimeMs, long loadDuration
    * @param chunkUid The chunk's uid.
    * @param shouldSpliceIn Whether the samples parsed from the chunk should be spliced into any
    *     samples already queued to the wrapper.
+   * @param reusingExtractor Whether the extractor for the chunk has already been used for preceding
+   *     chunks.
    */
-  public void init(int chunkUid, boolean shouldSpliceIn) {
+  public void init(int chunkUid, boolean shouldSpliceIn, boolean reusingExtractor) {
+    if (!reusingExtractor) {
+      audioSampleQueueMappingDone = false;
+      videoSampleQueueMappingDone = false;
+    }
     for (SampleQueue sampleQueue : sampleQueues) {
       sampleQueue.sourceId(chunkUid);
     }
@@ -633,14 +645,43 @@ public void init(int chunkUid, boolean shouldSpliceIn) {
   @Override
   public TrackOutput track(int id, int type) {
     int trackCount = sampleQueues.length;
-    for (int i = 0; i < trackCount; i++) {
-      if (sampleQueueTrackIds[i] == id) {
-        return sampleQueues[i];
+
+    // Audio and video tracks are handled manually to ignore ids.
+    if (type == C.TRACK_TYPE_AUDIO) {
+      if (audioSampleQueueIndex != C.INDEX_UNSET) {
+        if (audioSampleQueueMappingDone) {
+          return sampleQueueTrackIds[audioSampleQueueIndex] == id
+              ? sampleQueues[audioSampleQueueIndex]
+              : createDummyTrackOutput(id, type);
+        }
+        audioSampleQueueMappingDone = true;
+        sampleQueueTrackIds[audioSampleQueueIndex] = id;
+        return sampleQueues[audioSampleQueueIndex];
+      } else if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
+      }
+    } else if (type == C.TRACK_TYPE_VIDEO) {
+      if (videoSampleQueueIndex != C.INDEX_UNSET) {
+        if (videoSampleQueueMappingDone) {
+          return sampleQueueTrackIds[videoSampleQueueIndex] == id
+              ? sampleQueues[videoSampleQueueIndex]
+              : createDummyTrackOutput(id, type);
+        }
+        videoSampleQueueMappingDone = true;
+        sampleQueueTrackIds[videoSampleQueueIndex] = id;
+        return sampleQueues[videoSampleQueueIndex];
+      } else if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
+      }
+    } else /* sparse track */ {
+      for (int i = 0; i < trackCount; i++) {
+        if (sampleQueueTrackIds[i] == id) {
+          return sampleQueues[i];
+        }
+      }
+      if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
       }
-    }
-    if (tracksEnded) {
-      Log.w(TAG, "Unmapped track with id " + id + " of type " + type);
-      return new DummyTrackOutput();
     }
     SampleQueue trackOutput = new SampleQueue(allocator);
     trackOutput.setSampleOffsetUs(sampleOffsetUs);
@@ -653,6 +694,13 @@ public TrackOutput track(int id, int type) {
     sampleQueueIsAudioVideoFlags[trackCount] = type == C.TRACK_TYPE_AUDIO
         || type == C.TRACK_TYPE_VIDEO;
     haveAudioVideoSampleQueues |= sampleQueueIsAudioVideoFlags[trackCount];
+    if (type == C.TRACK_TYPE_AUDIO) {
+      audioSampleQueueMappingDone = true;
+      audioSampleQueueIndex = trackCount;
+    } else if (type == C.TRACK_TYPE_VIDEO) {
+      videoSampleQueueMappingDone = true;
+      videoSampleQueueIndex = trackCount;
+    }
     sampleQueuesEnabledStates = Arrays.copyOf(sampleQueuesEnabledStates, trackCount + 1);
     return trackOutput;
   }
@@ -913,4 +961,9 @@ private static boolean formatsMatch(Format manifestFormat, Format sampleFormat)
     }
     return true;
   }
+
+  private static DummyTrackOutput createDummyTrackOutput(int id, int type) {
+    Log.w(TAG, "Unmapped track with id " + id + " of type " + type);
+    return new DummyTrackOutput();
+  }
 }