Refactor #6.HLS.0

Mechanical step to create a new HlsSource in the library.
Note that naming is now confusing. This will be fixed in
the next CL, when:

HlsSource -> HlsSampleSource
HlsSampleSource+HlsOutput -> HlsOutput
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=122054800

demo/src/main/java/com/google/android/exoplayer/demo/PlayerActivity.java

@@ -24,18 +24,24 @@ import com.google.android.exoplayer.MediaCodecTrackRenderer.DecoderInitializatio
 import com.google.android.exoplayer.MediaCodecUtil.DecoderQueryException;
 import com.google.android.exoplayer.SampleSource;
 import com.google.android.exoplayer.TrackGroupArray;
+import com.google.android.exoplayer.dash.DashSampleSource;
 import com.google.android.exoplayer.demo.player.DemoPlayer;
-import com.google.android.exoplayer.demo.player.SourceBuilder;
 import com.google.android.exoplayer.demo.ui.TrackSelectionHelper;
 import com.google.android.exoplayer.drm.UnsupportedDrmException;
+import com.google.android.exoplayer.extractor.ExtractorSampleSource;
+import com.google.android.exoplayer.hls.HlsSource;
 import com.google.android.exoplayer.metadata.id3.GeobFrame;
 import com.google.android.exoplayer.metadata.id3.Id3Frame;
 import com.google.android.exoplayer.metadata.id3.PrivFrame;
 import com.google.android.exoplayer.metadata.id3.TxxxFrame;
+import com.google.android.exoplayer.smoothstreaming.SmoothStreamingSampleSource;
 import com.google.android.exoplayer.text.CaptionStyleCompat;
 import com.google.android.exoplayer.text.Cue;
 import com.google.android.exoplayer.text.SubtitleLayout;
+import com.google.android.exoplayer.upstream.Allocator;
+import com.google.android.exoplayer.upstream.DataSource;
 import com.google.android.exoplayer.upstream.DataSourceFactory;
+import com.google.android.exoplayer.upstream.DefaultAllocator;
 import com.google.android.exoplayer.upstream.DefaultDataSourceFactory;
 import com.google.android.exoplayer.util.DebugTextViewHelper;
 import com.google.android.exoplayer.util.Util;
@@ -260,18 +266,25 @@ public class PlayerActivity extends Activity implements SurfaceHolder.Callback,
 
   // Internal methods
 
+  @SuppressWarnings("unused")
   private SampleSource buildSource(Uri uri, String id, String provider, int type) {
     switch (type) {
       case Util.TYPE_SS:
-        return SourceBuilder.buildSmoothStreamingSource(player, dataSourceFactory, uri,
+        // TODO: Bring back DRM support. new SmoothStreamingTestMediaDrmCallback()
-            new SmoothStreamingTestMediaDrmCallback());
+        return new SmoothStreamingSampleSource(uri, dataSourceFactory, player.getBandwidthMeter(),
+            player.getMainHandler(), player);
       case Util.TYPE_DASH:
-        return SourceBuilder.buildDashSource(player, dataSourceFactory, uri,
+        // TODO: Bring back DRM support. new WidevineTestMediaDrmCallback(id, provider)
-            new WidevineTestMediaDrmCallback(id, provider));
+        return new DashSampleSource(uri, dataSourceFactory, player.getBandwidthMeter(),
+            player.getMainHandler(), player);
       case Util.TYPE_HLS:
-        return SourceBuilder.buildHlsSource(player, dataSourceFactory, uri);
+        return new HlsSource(uri, dataSourceFactory, player.getBandwidthMeter(),
+            player.getMainHandler(), player);
       case Util.TYPE_OTHER:
-        return SourceBuilder.buildExtractorSource(player, dataSourceFactory, uri);
+        Allocator allocator = new DefaultAllocator(C.DEFAULT_BUFFER_SEGMENT_SIZE);
+        DataSource dataSource = dataSourceFactory.createDataSource(player.getBandwidthMeter());
+        return new ExtractorSampleSource(uri, dataSource, allocator,
+            C.DEFAULT_MUXED_BUFFER_SIZE, player.getMainHandler(), player, 0);
       default:
         throw new IllegalStateException("Unsupported type: " + type);
     }

demo/src/main/java/com/google/android/exoplayer/demo/player/DemoPlayer.java

@@ -279,7 +279,7 @@ public class DemoPlayer implements ExoPlayer.Listener, DefaultTrackSelector.Even
     return player.getPlayWhenReady();
   }
 
-  /* package */ Handler getMainHandler() {
+  public Handler getMainHandler() {
     return mainHandler;
   }
 

demo/src/main/java/com/google/android/exoplayer/demo/player/SourceBuilder.java

@@ -1,109 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.google.android.exoplayer.demo.player;
-
-import com.google.android.exoplayer.C;
-import com.google.android.exoplayer.DefaultLoadControl;
-import com.google.android.exoplayer.LoadControl;
-import com.google.android.exoplayer.MultiSampleSource;
-import com.google.android.exoplayer.SampleSource;
-import com.google.android.exoplayer.chunk.FormatEvaluator;
-import com.google.android.exoplayer.dash.DashSampleSource;
-import com.google.android.exoplayer.drm.MediaDrmCallback;
-import com.google.android.exoplayer.extractor.ExtractorSampleSource;
-import com.google.android.exoplayer.hls.HlsChunkSource;
-import com.google.android.exoplayer.hls.HlsSampleSource;
-import com.google.android.exoplayer.hls.PtsTimestampAdjusterProvider;
-import com.google.android.exoplayer.hls.playlist.HlsPlaylist;
-import com.google.android.exoplayer.hls.playlist.HlsPlaylistParser;
-import com.google.android.exoplayer.smoothstreaming.SmoothStreamingSampleSource;
-import com.google.android.exoplayer.upstream.Allocator;
-import com.google.android.exoplayer.upstream.BandwidthMeter;
-import com.google.android.exoplayer.upstream.DataSource;
-import com.google.android.exoplayer.upstream.DataSourceFactory;
-import com.google.android.exoplayer.upstream.DefaultAllocator;
-import com.google.android.exoplayer.util.ManifestFetcher;
-
-import android.net.Uri;
-import android.os.Handler;
-
-/**
- * A utility class for building {@link SampleSource} instances.
- */
-public class SourceBuilder {
-
-  private SourceBuilder() {}
-
-  // TODO[REFACTOR]: Bring back DASH DRM support.
-  // TODO[REFACTOR]: Bring back DASH UTC timing element support.
-  public static SampleSource buildDashSource(DemoPlayer player, DataSourceFactory dataSourceFactory,
-      Uri uri, MediaDrmCallback drmCallback) {
-    return new DashSampleSource(uri, dataSourceFactory, player.getBandwidthMeter(),
-        player.getMainHandler(), player);
-  }
-
-  // TODO[REFACTOR]: Bring back DRM support.
-  public static SampleSource buildSmoothStreamingSource(DemoPlayer player,
-      DataSourceFactory dataSourceFactory, Uri uri, MediaDrmCallback drmCallback) {
-    return new SmoothStreamingSampleSource(uri, dataSourceFactory, player.getBandwidthMeter(),
-        player.getMainHandler(), player);
-  }
-
-  public static SampleSource buildHlsSource(DemoPlayer player, DataSourceFactory dataSourceFactory,
-      Uri uri) {
-    HlsPlaylistParser parser = new HlsPlaylistParser();
-    DataSource manifestDataSource = dataSourceFactory.createDataSource();
-    // TODO[REFACTOR]: This needs releasing.
-    ManifestFetcher<HlsPlaylist> manifestFetcher = new ManifestFetcher<>(uri, manifestDataSource,
-        parser);
-
-    Handler mainHandler = player.getMainHandler();
-    BandwidthMeter bandwidthMeter = player.getBandwidthMeter();
-    LoadControl loadControl = new DefaultLoadControl(
-        new DefaultAllocator(C.DEFAULT_BUFFER_SEGMENT_SIZE));
-    PtsTimestampAdjusterProvider timestampAdjusterProvider = new PtsTimestampAdjusterProvider();
-
-    DataSource defaultDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
-    HlsChunkSource defaultChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_DEFAULT,
-        defaultDataSource, timestampAdjusterProvider,
-        new FormatEvaluator.AdaptiveEvaluator(bandwidthMeter));
-    HlsSampleSource defaultSampleSource = new HlsSampleSource(defaultChunkSource, loadControl,
-        C.DEFAULT_MUXED_BUFFER_SIZE, mainHandler, player, C.TRACK_TYPE_VIDEO);
-
-    DataSource audioDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
-    HlsChunkSource audioChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_AUDIO,
-        audioDataSource, timestampAdjusterProvider, null);
-    HlsSampleSource audioSampleSource = new HlsSampleSource(audioChunkSource, loadControl,
-        C.DEFAULT_AUDIO_BUFFER_SIZE, mainHandler, player, C.TRACK_TYPE_AUDIO);
-
-    DataSource subtitleDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
-    HlsChunkSource subtitleChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_TEXT,
-        subtitleDataSource, timestampAdjusterProvider, null);
-    HlsSampleSource subtitleSampleSource = new HlsSampleSource(subtitleChunkSource, loadControl,
-        C.DEFAULT_TEXT_BUFFER_SIZE, mainHandler, player, C.TRACK_TYPE_TEXT);
-
-    return new MultiSampleSource(defaultSampleSource, audioSampleSource, subtitleSampleSource);
-  }
-
-  public static SampleSource buildExtractorSource(DemoPlayer player,
-      DataSourceFactory dataSourceFactory, Uri uri) {
-    Allocator allocator = new DefaultAllocator(C.DEFAULT_BUFFER_SEGMENT_SIZE);
-    DataSource dataSource = dataSourceFactory.createDataSource(player.getBandwidthMeter());
-    return new ExtractorSampleSource(uri, dataSource, allocator,
-        C.DEFAULT_MUXED_BUFFER_SIZE, player.getMainHandler(), player, 0);
-  }
-
-}

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

@@ -45,7 +45,7 @@ import java.util.List;
 /**
  * A {@link SampleSource} for HLS streams.
  */
-public final class HlsSampleSource implements SampleSource, Loader.Callback {
+public final class HlsSampleSource implements Loader.Callback {
 
   /**
    * The default minimum number of times to retry loading data prior to failing.
@@ -139,9 +139,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     pendingResetPositionUs = C.UNSET_TIME_US;
   }
 
-  // SampleSource implementation.
-
-  @Override
   public boolean prepare(long positionUs) throws IOException {
     if (prepared) {
       return true;
@@ -173,17 +170,14 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     return false;
   }
 
-  @Override
   public long getDurationUs() {
     return chunkSource.getDurationUs();
   }
 
-  @Override
   public TrackGroupArray getTrackGroups() {
     return trackGroups;
   }
 
-  @Override
   public TrackStream[] selectTracks(List<TrackStream> oldStreams,
       List<TrackSelection> newSelections, long positionUs) {
     Assertions.checkState(prepared);
@@ -233,7 +227,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     return newStreams;
   }
 
-  @Override
   public void continueBuffering(long playbackPositionUs) {
     downstreamPositionUs = playbackPositionUs;
     discardSamplesForDisabledTracks();
@@ -242,7 +235,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     }
   }
 
-  @Override
   public long readReset() {
     if (notifyReset) {
       notifyReset = false;
@@ -251,7 +243,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     return C.UNSET_TIME_US;
   }
 
-  @Override
   public long getBufferedPositionUs() {
     if (loadingFinished) {
       return C.END_OF_SOURCE_US;
@@ -273,12 +264,10 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     }
   }
 
-  @Override
   public void seekToUs(long positionUs) {
     seekToInternal(positionUs);
   }
 
-  @Override
   public void release() {
     if (enabledTrackCount > 0) {
       loadControl.unregister(this);

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

@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer.hls;
+
+import com.google.android.exoplayer.C;
+import com.google.android.exoplayer.DefaultLoadControl;
+import com.google.android.exoplayer.LoadControl;
+import com.google.android.exoplayer.SampleSource;
+import com.google.android.exoplayer.TrackGroup;
+import com.google.android.exoplayer.TrackGroupArray;
+import com.google.android.exoplayer.TrackSelection;
+import com.google.android.exoplayer.TrackStream;
+import com.google.android.exoplayer.chunk.ChunkTrackStreamEventListener;
+import com.google.android.exoplayer.chunk.FormatEvaluator;
+import com.google.android.exoplayer.hls.playlist.HlsPlaylist;
+import com.google.android.exoplayer.hls.playlist.HlsPlaylistParser;
+import com.google.android.exoplayer.upstream.BandwidthMeter;
+import com.google.android.exoplayer.upstream.DataSource;
+import com.google.android.exoplayer.upstream.DataSourceFactory;
+import com.google.android.exoplayer.upstream.DefaultAllocator;
+import com.google.android.exoplayer.util.Assertions;
+import com.google.android.exoplayer.util.ManifestFetcher;
+
+import android.net.Uri;
+import android.os.Handler;
+import android.util.Pair;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.IdentityHashMap;
+import java.util.List;
+
+/**
+ * A {@link SampleSource} for HLS streams.
+ */
+public final class HlsSource implements SampleSource {
+
+  private final ManifestFetcher<HlsPlaylist> manifestFetcher;
+  private final HlsSampleSource[] sources;
+  private final IdentityHashMap<TrackStream, HlsSampleSource> trackStreamSources;
+  private final int[] selectedTrackCounts;
+
+  private boolean prepared;
+  private boolean seenFirstTrackSelection;
+  private long durationUs;
+  private TrackGroupArray trackGroups;
+  private HlsSampleSource[] enabledSources;
+
+  public HlsSource(Uri uri, DataSourceFactory dataSourceFactory, BandwidthMeter bandwidthMeter,
+      Handler eventHandler, ChunkTrackStreamEventListener eventListener) {
+    HlsPlaylistParser parser = new HlsPlaylistParser();
+    DataSource manifestDataSource = dataSourceFactory.createDataSource();
+    manifestFetcher = new ManifestFetcher<>(uri, manifestDataSource, parser);
+
+    LoadControl loadControl = new DefaultLoadControl(
+        new DefaultAllocator(C.DEFAULT_BUFFER_SEGMENT_SIZE));
+    PtsTimestampAdjusterProvider timestampAdjusterProvider = new PtsTimestampAdjusterProvider();
+
+    DataSource defaultDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
+    HlsChunkSource defaultChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_DEFAULT,
+        defaultDataSource, timestampAdjusterProvider,
+        new FormatEvaluator.AdaptiveEvaluator(bandwidthMeter));
+    HlsSampleSource defaultSampleSource = new HlsSampleSource(defaultChunkSource, loadControl,
+        C.DEFAULT_MUXED_BUFFER_SIZE, eventHandler, eventListener, C.TRACK_TYPE_VIDEO);
+
+    DataSource audioDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
+    HlsChunkSource audioChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_AUDIO,
+        audioDataSource, timestampAdjusterProvider, null);
+    HlsSampleSource audioSampleSource = new HlsSampleSource(audioChunkSource, loadControl,
+        C.DEFAULT_AUDIO_BUFFER_SIZE, eventHandler, eventListener, C.TRACK_TYPE_AUDIO);
+
+    DataSource subtitleDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
+    HlsChunkSource subtitleChunkSource = new HlsChunkSource(manifestFetcher, C.TRACK_TYPE_TEXT,
+        subtitleDataSource, timestampAdjusterProvider, null);
+    HlsSampleSource subtitleSampleSource = new HlsSampleSource(subtitleChunkSource, loadControl,
+        C.DEFAULT_TEXT_BUFFER_SIZE, eventHandler, eventListener, C.TRACK_TYPE_TEXT);
+
+    sources = new HlsSampleSource[] {defaultSampleSource, audioSampleSource, subtitleSampleSource};
+    selectedTrackCounts = new int[sources.length];
+    trackStreamSources = new IdentityHashMap<>();
+  }
+
+  @Override
+  public boolean prepare(long positionUs) throws IOException {
+    if (prepared) {
+      return true;
+    }
+    boolean sourcesPrepared = true;
+    for (HlsSampleSource source : sources) {
+      sourcesPrepared &= source.prepare(positionUs);
+    }
+    if (!sourcesPrepared) {
+      return false;
+    }
+    durationUs = 0;
+    int totalTrackGroupCount = 0;
+    for (HlsSampleSource source : sources) {
+      totalTrackGroupCount += source.getTrackGroups().length;
+      if (durationUs != C.UNSET_TIME_US) {
+        long sourceDurationUs = source.getDurationUs();
+        durationUs = sourceDurationUs == C.UNSET_TIME_US
+            ? C.UNSET_TIME_US : Math.max(durationUs, sourceDurationUs);
+      }
+    }
+    TrackGroup[] trackGroupArray = new TrackGroup[totalTrackGroupCount];
+    int trackGroupIndex = 0;
+    for (HlsSampleSource source : sources) {
+      int sourceTrackGroupCount = source.getTrackGroups().length;
+      for (int j = 0; j < sourceTrackGroupCount; j++) {
+        trackGroupArray[trackGroupIndex++] = source.getTrackGroups().get(j);
+      }
+    }
+    trackGroups = new TrackGroupArray(trackGroupArray);
+    prepared = true;
+    return true;
+  }
+
+  @Override
+  public long getDurationUs() {
+    return durationUs;
+  }
+
+  @Override
+  public TrackGroupArray getTrackGroups() {
+    return trackGroups;
+  }
+
+  @Override
+  public TrackStream[] selectTracks(List<TrackStream> oldStreams,
+      List<TrackSelection> newSelections, long positionUs) {
+    Assertions.checkState(prepared);
+    TrackStream[] newStreams = new TrackStream[newSelections.size()];
+    // Select tracks for each source.
+    int enabledSourceCount = 0;
+    for (int i = 0; i < sources.length; i++) {
+      selectedTrackCounts[i] += selectTracks(sources[i], oldStreams, newSelections, positionUs,
+          newStreams);
+      if (selectedTrackCounts[i] > 0) {
+        enabledSourceCount++;
+      }
+    }
+    // Update the enabled sources.
+    enabledSources = new HlsSampleSource[enabledSourceCount];
+    enabledSourceCount = 0;
+    for (int i = 0; i < sources.length; i++) {
+      if (selectedTrackCounts[i] > 0) {
+        enabledSources[enabledSourceCount++] = sources[i];
+      }
+    }
+    seenFirstTrackSelection = true;
+    return newStreams;
+  }
+
+  @Override
+  public void continueBuffering(long positionUs) {
+    for (HlsSampleSource source : enabledSources) {
+      source.continueBuffering(positionUs);
+    }
+  }
+
+  @Override
+  public long readReset() {
+    long resetPositionUs = C.UNSET_TIME_US;
+    for (HlsSampleSource 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;
+    for (HlsSampleSource source : enabledSources) {
+      long rendererBufferedPositionUs = source.getBufferedPositionUs();
+      if (rendererBufferedPositionUs == C.UNSET_TIME_US) {
+        return C.UNSET_TIME_US;
+      } else if (rendererBufferedPositionUs == C.END_OF_SOURCE_US) {
+        // This source is fully buffered.
+      } else {
+        bufferedPositionUs = Math.min(bufferedPositionUs, rendererBufferedPositionUs);
+      }
+    }
+    return bufferedPositionUs == Long.MAX_VALUE ? C.UNSET_TIME_US : bufferedPositionUs;
+  }
+
+  @Override
+  public void seekToUs(long positionUs) {
+    for (HlsSampleSource source : enabledSources) {
+      source.seekToUs(positionUs);
+    }
+  }
+
+  @Override
+  public void release() {
+    manifestFetcher.release();
+    for (HlsSampleSource source : sources) {
+      source.release();
+    }
+  }
+
+  // Internal methods.
+
+  private int selectTracks(HlsSampleSource source, List<TrackStream> allOldStreams,
+      List<TrackSelection> allNewSelections, long positionUs, TrackStream[] allNewStreams) {
+    // Get the subset of the old streams for the source.
+    ArrayList<TrackStream> oldStreams = new ArrayList<>();
+    for (int i = 0; i < allOldStreams.size(); i++) {
+      TrackStream stream = allOldStreams.get(i);
+      if (trackStreamSources.get(stream) == source) {
+        trackStreamSources.remove(stream);
+        oldStreams.add(stream);
+      }
+    }
+    // Get the subset of the new selections for the source.
+    ArrayList<TrackSelection> newSelections = new ArrayList<>();
+    int[] newSelectionOriginalIndices = new int[allNewSelections.size()];
+    for (int i = 0; i < allNewSelections.size(); i++) {
+      TrackSelection selection = allNewSelections.get(i);
+      Pair<HlsSampleSource, Integer> sourceAndGroup = getSourceAndGroup(selection.group);
+      if (sourceAndGroup.first == source) {
+        newSelectionOriginalIndices[newSelections.size()] = i;
+        newSelections.add(new TrackSelection(sourceAndGroup.second, selection.getTracks()));
+      }
+    }
+    // Do nothing if nothing has changed, except during the first selection.
+    if (seenFirstTrackSelection && oldStreams.isEmpty() && newSelections.isEmpty()) {
+      return 0;
+    }
+    // Perform the selection.
+    TrackStream[] newStreams = source.selectTracks(oldStreams, newSelections, positionUs);
+    for (int j = 0; j < newStreams.length; j++) {
+      allNewStreams[newSelectionOriginalIndices[j]] = newStreams[j];
+      trackStreamSources.put(newStreams[j], source);
+    }
+    return newSelections.size() - oldStreams.size();
+  }
+
+  private Pair<HlsSampleSource, Integer> getSourceAndGroup(int group) {
+    int totalTrackGroupCount = 0;
+    for (HlsSampleSource source : sources) {
+      int sourceTrackGroupCount = source.getTrackGroups().length;
+      if (group < totalTrackGroupCount + sourceTrackGroupCount) {
+        return Pair.create(source, group - totalTrackGroupCount);
+      }
+      totalTrackGroupCount += sourceTrackGroupCount;
+    }
+    throw new IndexOutOfBoundsException();
+  }
+
+}