Refactor #6.HLS.4

Pull more logic up to HlsSampleSource. Somewhat regretfully,
this also backs out the optimization work done toward the
ref'd issue. I think that's one for another time perhaps...

Issue: #551
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=123417413

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

@@ -28,9 +28,7 @@ import com.google.android.exoplayer.extractor.mp3.Mp3Extractor;
 import com.google.android.exoplayer.extractor.ts.AdtsExtractor;
 import com.google.android.exoplayer.extractor.ts.PtsTimestampAdjuster;
 import com.google.android.exoplayer.extractor.ts.TsExtractor;
-import com.google.android.exoplayer.hls.playlist.HlsMasterPlaylist;
 import com.google.android.exoplayer.hls.playlist.HlsMediaPlaylist;
-import com.google.android.exoplayer.hls.playlist.HlsPlaylist;
 import com.google.android.exoplayer.hls.playlist.HlsPlaylistParser;
 import com.google.android.exoplayer.hls.playlist.Variant;
 import com.google.android.exoplayer.upstream.DataSource;
@@ -48,10 +46,8 @@ import android.util.Log;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.math.BigInteger;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
-import java.util.List;
 import java.util.Locale;
 
 /**
@@ -70,54 +66,53 @@ public class HlsChunkSource {
   private static final String VTT_FILE_EXTENSION = ".vtt";
   private static final String WEBVTT_FILE_EXTENSION = ".webvtt";
 
-  private final int type;
+  private final String baseUri;
   private final DataSource dataSource;
   private final FormatEvaluator adaptiveFormatEvaluator;
   private final Evaluation evaluation;
   private final HlsPlaylistParser playlistParser;
   private final PtsTimestampAdjusterProvider timestampAdjusterProvider;
+  private final Variant[] variants;
+  private final HlsMediaPlaylist[] variantPlaylists;
+  private final long[] variantLastPlaylistLoadTimesMs;
 
   private byte[] scratchSpace;
   private boolean live;
   private long durationUs;
   private IOException fatalError;
-  private String baseUri;
-  private Format muxedAudioFormat;
-  private Format muxedCaptionFormat;
 
   private Uri encryptionKeyUri;
   private byte[] encryptionKey;
   private String encryptionIvString;
   private byte[] encryptionIv;
 
-  // Properties of exposed tracks.
-  private Variant[] variants;
-  private HlsMediaPlaylist[] variantPlaylists;
-  private long[] variantLastPlaylistLoadTimesMs;
-
   // Properties of enabled variants.
   private Variant[] enabledVariants;
   private long[] enabledVariantBlacklistTimes;
   private boolean[] enabledVariantBlacklistFlags;
 
   /**
-   * @param type The type of chunk provided by the source. One of {@link C#TRACK_TYPE_DEFAULT},
+   * @param baseUri The playlist's base uri.
-   *     {@link C#TRACK_TYPE_AUDIO} and {@link C#TRACK_TYPE_TEXT}.
+   * @param variants The available variants.
    * @param dataSource A {@link DataSource} suitable for loading the media data.
    * @param timestampAdjusterProvider A provider of {@link PtsTimestampAdjuster} instances. If
    *     multiple {@link HlsChunkSource}s are used for a single playback, they should all share the
    *     same provider.
    * @param adaptiveFormatEvaluator For adaptive tracks, selects from the available formats.
    */
-  public HlsChunkSource(int type, DataSource dataSource,
+  public HlsChunkSource(String baseUri, Variant[] variants, DataSource dataSource,
       PtsTimestampAdjusterProvider timestampAdjusterProvider,
       FormatEvaluator adaptiveFormatEvaluator) {
-    this.type = type;
+    this.baseUri = baseUri;
+    this.variants = variants;
     this.dataSource = dataSource;
     this.adaptiveFormatEvaluator = adaptiveFormatEvaluator;
     this.timestampAdjusterProvider = timestampAdjusterProvider;
     playlistParser = new HlsPlaylistParser();
     evaluation = new Evaluation();
+    variantPlaylists = new HlsMediaPlaylist[variants.length];
+    variantLastPlaylistLoadTimesMs = new long[variants.length];
+    selectTracks(new int[] {0});
   }
 
   /**
@@ -141,19 +136,6 @@ public class HlsChunkSource {
     return adaptiveFormatEvaluator != null;
   }
 
-  /**
-   * Prepares the source.
-   *
-   * @param playlist A {@link HlsPlaylist}.
-   */
-  public void prepare(HlsPlaylist playlist) {
-    processPlaylist(playlist);
-    if (variants.length > 0) {
-      // Select the first variant listed in the master playlist.
-      selectTracks(new int[] {0});
-    }
-  }
-
   /**
    * Returns whether this is a live playback.
    * <p>
@@ -199,28 +181,6 @@ public class HlsChunkSource {
     return variants[index].format;
   }
 
-  /**
-   * Returns the format of the audio muxed into variants, or null if unknown.
-   * <p>
-   * This method should only be called after the source has been prepared.
-   *
-   * @return The format of the audio muxed into variants, or null if unknown.
-   */
-  public Format getMuxedAudioFormat() {
-    return muxedAudioFormat;
-  }
-
-  /**
-   * Returns the format of the captions muxed into variants, or null if unknown.
-   * <p>
-   * This method should only be called after the source has been prepared.
-   *
-   * @return The format of the captions muxed into variants, or null if unknown.
-   */
-  public Format getMuxedCaptionFormat() {
-    return muxedCaptionFormat;
-  }
-
   /**
    * Selects tracks for use.
    * <p>
@@ -269,17 +229,6 @@ public class HlsChunkSource {
     return false;
   }
 
-  /**
-   * Notifies the source that a seek has occurred.
-   * <p>
-   * This method should only be called after the source has been prepared.
-   */
-  public void seek() {
-    if (type == C.TRACK_TYPE_DEFAULT) {
-      timestampAdjusterProvider.reset();
-    }
-  }
-
   /**
    * Resets the source.
    * <p>
@@ -493,90 +442,6 @@ public class HlsChunkSource {
 
   // Private methods.
 
-  private void processPlaylist(HlsPlaylist playlist) {
-    baseUri = playlist.baseUri;
-
-    if (playlist instanceof HlsMediaPlaylist) {
-      if (type == C.TRACK_TYPE_TEXT || type == C.TRACK_TYPE_AUDIO) {
-        variants = new Variant[0];
-        variantPlaylists = new HlsMediaPlaylist[variants.length];
-        variantLastPlaylistLoadTimesMs = new long[variants.length];
-        return;
-      }
-
-      // type == C.TRACK_TYPE_DEFAULT
-      Format format = Format.createContainerFormat("0", MimeTypes.APPLICATION_M3U8, null,
-          Format.NO_VALUE);
-      variants = new Variant[] {new Variant(baseUri, format, null)};
-      variantPlaylists = new HlsMediaPlaylist[variants.length];
-      variantLastPlaylistLoadTimesMs = new long[variants.length];
-      setMediaPlaylist(0, (HlsMediaPlaylist) playlist);
-      return;
-    }
-
-    HlsMasterPlaylist masterPlaylist = (HlsMasterPlaylist) playlist;
-    muxedAudioFormat = masterPlaylist.muxedAudioFormat;
-    muxedCaptionFormat = masterPlaylist.muxedCaptionFormat;
-    if (type == C.TRACK_TYPE_TEXT || type == C.TRACK_TYPE_AUDIO) {
-      List<Variant> variantList = type == C.TRACK_TYPE_AUDIO ? masterPlaylist.audios
-          : masterPlaylist.subtitles;
-      if (variantList != null && !variantList.isEmpty()) {
-        variants = new Variant[variantList.size()];
-        variantList.toArray(variants);
-      } else {
-        variants = new Variant[0];
-      }
-      variantPlaylists = new HlsMediaPlaylist[variants.length];
-      variantLastPlaylistLoadTimesMs = new long[variants.length];
-      return;
-    }
-
-    // type == C.TRACK_TYPE_DEFAULT
-    List<Variant> enabledVariantList = new ArrayList<>(masterPlaylist.variants);
-    ArrayList<Variant> definiteVideoVariants = new ArrayList<>();
-    ArrayList<Variant> definiteAudioOnlyVariants = new ArrayList<>();
-    for (int i = 0; i < enabledVariantList.size(); i++) {
-      Variant variant = enabledVariantList.get(i);
-      if (variant.format.height > 0 || variantHasExplicitCodecWithPrefix(variant, "avc")) {
-        definiteVideoVariants.add(variant);
-      } else if (variantHasExplicitCodecWithPrefix(variant, "mp4a")) {
-        definiteAudioOnlyVariants.add(variant);
-      }
-    }
-
-    if (!definiteVideoVariants.isEmpty()) {
-      // We've identified some variants as definitely containing video. Assume variants within the
-      // master playlist are marked consistently, and hence that we have the full set. Filter out
-      // any other variants, which are likely to be audio only.
-      enabledVariantList = definiteVideoVariants;
-    } else if (definiteAudioOnlyVariants.size() < enabledVariantList.size()) {
-      // We've identified some variants, but not all, as being audio only. Filter them out to leave
-      // the remaining variants, which are likely to contain video.
-      enabledVariantList.removeAll(definiteAudioOnlyVariants);
-    } else {
-      // Leave the enabled variants unchanged. They're likely either all video or all audio.
-    }
-
-    variants = new Variant[enabledVariantList.size()];
-    enabledVariantList.toArray(variants);
-    variantPlaylists = new HlsMediaPlaylist[variants.length];
-    variantLastPlaylistLoadTimesMs = new long[variants.length];
-  }
-
-  private static boolean variantHasExplicitCodecWithPrefix(Variant variant, String prefix) {
-    String codecs = variant.codecs;
-    if (TextUtils.isEmpty(codecs)) {
-      return false;
-    }
-    String[] codecArray = codecs.split("(\\s*,\\s*)|(\\s*$)");
-    for (String codec : codecArray) {
-      if (codec.startsWith(prefix)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
   private int getNextVariantIndex(HlsMediaChunk previous, long playbackPositionUs) {
     clearStaleBlacklistedVariants();
     if (enabledVariants.length > 1) {

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

@@ -17,6 +17,7 @@ package com.google.android.exoplayer.hls;
 
 import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.DefaultLoadControl;
+import com.google.android.exoplayer.Format;
 import com.google.android.exoplayer.LoadControl;
 import com.google.android.exoplayer.SampleSource;
 import com.google.android.exoplayer.TrackGroup;
@@ -25,17 +26,21 @@ 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.HlsMasterPlaylist;
+import com.google.android.exoplayer.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer.hls.playlist.HlsPlaylist;
 import com.google.android.exoplayer.hls.playlist.HlsPlaylistParser;
+import com.google.android.exoplayer.hls.playlist.Variant;
 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 com.google.android.exoplayer.util.MimeTypes;
 
 import android.net.Uri;
 import android.os.Handler;
+import android.text.TextUtils;
 import android.util.Pair;
 
 import java.io.IOException;
@@ -54,75 +59,59 @@ public final class HlsSampleSource implements SampleSource {
   // TODO: Use this for playlist loads as well.
   private static final int MIN_LOADABLE_RETRY_COUNT = 3;
 
-  private final ManifestFetcher<HlsPlaylist> manifestFetcher;
+  private final DataSourceFactory dataSourceFactory;
-  private final HlsChunkSource[] chunkSources;
+  private final BandwidthMeter bandwidthMeter;
-  private final HlsTrackStreamWrapper[] trackStreamWrappers;
+  private final Handler eventHandler;
+  private final ChunkTrackStreamEventListener eventListener;
+  private final LoadControl loadControl;
   private final IdentityHashMap<TrackStream, HlsTrackStreamWrapper> trackStreamSources;
-  private final int[] selectedTrackCounts;
+  private final PtsTimestampAdjusterProvider timestampAdjusterProvider;
+  private final ManifestFetcher<HlsPlaylist> manifestFetcher;
 
-  private boolean prepared;
   private boolean seenFirstTrackSelection;
   private long durationUs;
-  private HlsPlaylist playlist;
+  private boolean isLive;
   private TrackGroupArray trackGroups;
+  private int[] selectedTrackCounts;
+  private HlsTrackStreamWrapper[] trackStreamWrappers;
   private HlsTrackStreamWrapper[] enabledTrackStreamWrappers;
+  private boolean pendingReset;
+  private long lastSeekPositionUs;
 
   public HlsSampleSource(Uri uri, DataSourceFactory dataSourceFactory,
       BandwidthMeter bandwidthMeter, Handler eventHandler,
       ChunkTrackStreamEventListener eventListener) {
+    this.dataSourceFactory = dataSourceFactory;
+    this.bandwidthMeter = bandwidthMeter;
+    this.eventHandler = eventHandler;
+    this.eventListener = eventListener;
+
+    loadControl = new DefaultLoadControl(new DefaultAllocator(C.DEFAULT_BUFFER_SEGMENT_SIZE));
+    timestampAdjusterProvider = new PtsTimestampAdjusterProvider();
+    trackStreamSources = new IdentityHashMap<>();
+
     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(C.TRACK_TYPE_DEFAULT,
-        defaultDataSource, timestampAdjusterProvider,
-        new FormatEvaluator.AdaptiveEvaluator(bandwidthMeter));
-    HlsTrackStreamWrapper defaultTrackStreamWrapper = new HlsTrackStreamWrapper(defaultChunkSource,
-        loadControl, C.DEFAULT_MUXED_BUFFER_SIZE, eventHandler, eventListener, C.TRACK_TYPE_VIDEO,
-        MIN_LOADABLE_RETRY_COUNT);
-
-    DataSource audioDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
-    HlsChunkSource audioChunkSource = new HlsChunkSource(C.TRACK_TYPE_AUDIO,
-        audioDataSource, timestampAdjusterProvider, null);
-    HlsTrackStreamWrapper audioTrackStreamWrapper = new HlsTrackStreamWrapper(audioChunkSource,
-        loadControl, C.DEFAULT_AUDIO_BUFFER_SIZE, eventHandler, eventListener, C.TRACK_TYPE_AUDIO,
-        MIN_LOADABLE_RETRY_COUNT);
-
-    DataSource textDataSource = dataSourceFactory.createDataSource(bandwidthMeter);
-    HlsChunkSource textChunkSource = new HlsChunkSource(C.TRACK_TYPE_TEXT, textDataSource,
-        timestampAdjusterProvider, null);
-    HlsTrackStreamWrapper textTrackStreamWrapper = new HlsTrackStreamWrapper(
-        textChunkSource, loadControl, C.DEFAULT_TEXT_BUFFER_SIZE, eventHandler, eventListener,
-        C.TRACK_TYPE_TEXT, MIN_LOADABLE_RETRY_COUNT);
-
-    chunkSources = new HlsChunkSource[] {defaultChunkSource, audioChunkSource, textChunkSource};
-    trackStreamWrappers = new HlsTrackStreamWrapper[] {defaultTrackStreamWrapper,
-        audioTrackStreamWrapper, textTrackStreamWrapper};
-    selectedTrackCounts = new int[trackStreamWrappers.length];
-    trackStreamSources = new IdentityHashMap<>();
   }
 
   @Override
   public boolean prepare(long positionUs) throws IOException {
-    if (prepared) {
+    if (trackGroups != null) {
       return true;
     }
 
-    if (playlist == null) {
+    if (trackStreamWrappers == null) {
-      playlist = manifestFetcher.getManifest();
+      HlsPlaylist playlist = manifestFetcher.getManifest();
       if (playlist == null) {
         manifestFetcher.maybeThrowError();
         manifestFetcher.requestRefresh();
         return false;
       }
-      for (HlsChunkSource chunkSource : chunkSources) {
+      List<HlsTrackStreamWrapper> trackStreamWrapperList = buildTrackStreamWrappers(playlist);
-        chunkSource.prepare(playlist);
+      trackStreamWrappers = new HlsTrackStreamWrapper[trackStreamWrapperList.size()];
-      }
+      trackStreamWrapperList.toArray(trackStreamWrappers);
+      selectedTrackCounts = new int[trackStreamWrappers.length];
     }
 
     boolean trackStreamWrappersPrepared = true;
@@ -133,15 +122,13 @@ public final class HlsSampleSource implements SampleSource {
       return false;
     }
 
-    durationUs = 0;
+    // The wrapper at index 0 is the one of type TRACK_TYPE_DEFAULT.
+    durationUs = trackStreamWrappers[0].getDurationUs();
+    isLive = trackStreamWrappers[0].isLive();
+
     int totalTrackGroupCount = 0;
     for (HlsTrackStreamWrapper trackStreamWrapper : trackStreamWrappers) {
       totalTrackGroupCount += trackStreamWrapper.getTrackGroups().length;
-      if (durationUs != C.UNSET_TIME_US) {
-        long wrapperDurationUs = trackStreamWrapper.getDurationUs();
-        durationUs = wrapperDurationUs == C.UNSET_TIME_US
-            ? C.UNSET_TIME_US : Math.max(durationUs, wrapperDurationUs);
-      }
     }
     TrackGroup[] trackGroupArray = new TrackGroup[totalTrackGroupCount];
     int trackGroupIndex = 0;
@@ -152,7 +139,6 @@ public final class HlsSampleSource implements SampleSource {
       }
     }
     trackGroups = new TrackGroupArray(trackGroupArray);
-    prepared = true;
     return true;
   }
 
@@ -169,7 +155,6 @@ public final class HlsSampleSource implements SampleSource {
   @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 wrapper.
     int enabledTrackStreamWrapperCount = 0;
@@ -201,37 +186,37 @@ public final class HlsSampleSource implements SampleSource {
 
   @Override
   public long readReset() {
-    long resetPositionUs = C.UNSET_TIME_US;
+    if (pendingReset) {
-    for (HlsTrackStreamWrapper trackStreamWrapper : enabledTrackStreamWrappers) {
+      pendingReset = false;
-      long childResetPositionUs = trackStreamWrapper.readReset();
+      for (HlsTrackStreamWrapper trackStreamWrapper : trackStreamWrappers) {
-      if (resetPositionUs == C.UNSET_TIME_US) {
+        trackStreamWrapper.setReadingEnabled(true);
-        resetPositionUs = childResetPositionUs;
-      } else if (childResetPositionUs != C.UNSET_TIME_US) {
-        resetPositionUs = Math.min(resetPositionUs, childResetPositionUs);
       }
+      return lastSeekPositionUs;
     }
-    return resetPositionUs;
+    return C.UNSET_TIME_US;
   }
 
   @Override
   public long getBufferedPositionUs() {
-    long bufferedPositionUs = durationUs != C.UNSET_TIME_US ? durationUs : Long.MAX_VALUE;
+    long bufferedPositionUs = Long.MAX_VALUE;
     for (HlsTrackStreamWrapper trackStreamWrapper : enabledTrackStreamWrappers) {
       long rendererBufferedPositionUs = trackStreamWrapper.getBufferedPositionUs();
-      if (rendererBufferedPositionUs == C.UNSET_TIME_US) {
+      if (rendererBufferedPositionUs != C.END_OF_SOURCE_US) {
-        return C.UNSET_TIME_US;
-      } else if (rendererBufferedPositionUs == C.END_OF_SOURCE_US) {
-        // This wrapper is fully buffered.
-      } else {
         bufferedPositionUs = Math.min(bufferedPositionUs, rendererBufferedPositionUs);
       }
     }
-    return bufferedPositionUs == Long.MAX_VALUE ? C.UNSET_TIME_US : bufferedPositionUs;
+    return bufferedPositionUs == Long.MAX_VALUE ? C.END_OF_SOURCE_US : bufferedPositionUs;
   }
 
   @Override
   public void seekToUs(long positionUs) {
+    // Treat all seeks into non-seekable media as being to t=0.
+    positionUs = isLive ? 0 : positionUs;
+    lastSeekPositionUs = positionUs;
+    pendingReset = true;
+    timestampAdjusterProvider.reset();
     for (HlsTrackStreamWrapper trackStreamWrapper : enabledTrackStreamWrappers) {
+      trackStreamWrapper.setReadingEnabled(false);
       trackStreamWrapper.seekToUs(positionUs);
     }
   }
@@ -239,13 +224,92 @@ public final class HlsSampleSource implements SampleSource {
   @Override
   public void release() {
     manifestFetcher.release();
-    for (HlsTrackStreamWrapper trackStreamWrapper : trackStreamWrappers) {
+    if (trackStreamWrappers != null) {
-      trackStreamWrapper.release();
+      for (HlsTrackStreamWrapper trackStreamWrapper : trackStreamWrappers) {
+        trackStreamWrapper.release();
+      }
     }
   }
 
   // Internal methods.
 
+  private List<HlsTrackStreamWrapper> buildTrackStreamWrappers(HlsPlaylist playlist) {
+    ArrayList<HlsTrackStreamWrapper> trackStreamWrappers = new ArrayList<>();
+    String baseUri = playlist.baseUri;
+
+    if (playlist instanceof HlsMediaPlaylist) {
+      Format format = Format.createContainerFormat("0", MimeTypes.APPLICATION_M3U8, null,
+          Format.NO_VALUE);
+      Variant[] variants = new Variant[] {new Variant(playlist.baseUri, format, null)};
+      trackStreamWrappers.add(buildTrackStreamWrapper(C.TRACK_TYPE_DEFAULT, baseUri, variants,
+          new FormatEvaluator.AdaptiveEvaluator(bandwidthMeter), C.DEFAULT_MUXED_BUFFER_SIZE,
+          null, null));
+      return trackStreamWrappers;
+    }
+
+    HlsMasterPlaylist masterPlaylist = (HlsMasterPlaylist) playlist;
+
+    // Build the default stream wrapper.
+    List<Variant> selectedVariants = new ArrayList<>(masterPlaylist.variants);
+    ArrayList<Variant> definiteVideoVariants = new ArrayList<>();
+    ArrayList<Variant> definiteAudioOnlyVariants = new ArrayList<>();
+    for (int i = 0; i < selectedVariants.size(); i++) {
+      Variant variant = selectedVariants.get(i);
+      if (variant.format.height > 0 || variantHasExplicitCodecWithPrefix(variant, "avc")) {
+        definiteVideoVariants.add(variant);
+      } else if (variantHasExplicitCodecWithPrefix(variant, "mp4a")) {
+        definiteAudioOnlyVariants.add(variant);
+      }
+    }
+    if (!definiteVideoVariants.isEmpty()) {
+      // We've identified some variants as definitely containing video. Assume variants within the
+      // master playlist are marked consistently, and hence that we have the full set. Filter out
+      // any other variants, which are likely to be audio only.
+      selectedVariants = definiteVideoVariants;
+    } else if (definiteAudioOnlyVariants.size() < selectedVariants.size()) {
+      // We've identified some variants, but not all, as being audio only. Filter them out to leave
+      // the remaining variants, which are likely to contain video.
+      selectedVariants.removeAll(definiteAudioOnlyVariants);
+    } else {
+      // Leave the enabled variants unchanged. They're likely either all video or all audio.
+    }
+    Variant[] variants = new Variant[selectedVariants.size()];
+    selectedVariants.toArray(variants);
+    trackStreamWrappers.add(buildTrackStreamWrapper(C.TRACK_TYPE_DEFAULT, baseUri, variants,
+        new FormatEvaluator.AdaptiveEvaluator(bandwidthMeter), C.DEFAULT_MUXED_BUFFER_SIZE,
+        masterPlaylist.muxedAudioFormat, masterPlaylist.muxedCaptionFormat));
+
+    // Build the audio stream wrapper if applicable.
+    List<Variant> audioVariants = masterPlaylist.audios;
+    if (!audioVariants.isEmpty()) {
+      variants = new Variant[audioVariants.size()];
+      audioVariants.toArray(variants);
+      trackStreamWrappers.add(buildTrackStreamWrapper(C.TRACK_TYPE_AUDIO, baseUri, variants, null,
+          C.DEFAULT_AUDIO_BUFFER_SIZE, null, null));
+    }
+
+    // Build the text stream wrapper if applicable.
+    List<Variant> subtitleVariants = masterPlaylist.subtitles;
+    if (!subtitleVariants.isEmpty()) {
+      variants = new Variant[subtitleVariants.size()];
+      subtitleVariants.toArray(variants);
+      trackStreamWrappers.add(buildTrackStreamWrapper(C.TRACK_TYPE_TEXT, baseUri, variants, null,
+          C.DEFAULT_TEXT_BUFFER_SIZE, null, null));
+    }
+
+    return trackStreamWrappers;
+  }
+
+  private HlsTrackStreamWrapper buildTrackStreamWrapper(int trackType, String baseUri,
+      Variant[] variants, FormatEvaluator formatEvaluator, int bufferSize, Format muxedAudioFormat,
+      Format muxedCaptionFormat) {
+    DataSource dataSource = dataSourceFactory.createDataSource(bandwidthMeter);
+    HlsChunkSource defaultChunkSource = new HlsChunkSource(baseUri, variants, dataSource,
+        timestampAdjusterProvider, formatEvaluator);
+    return new HlsTrackStreamWrapper(defaultChunkSource, loadControl, bufferSize, muxedAudioFormat,
+        muxedCaptionFormat, eventHandler, eventListener, trackType, MIN_LOADABLE_RETRY_COUNT);
+  }
+
   private int selectTracks(HlsTrackStreamWrapper trackStreamWrapper,
       List<TrackStream> allOldStreams, List<TrackSelection> allNewSelections, long positionUs,
       TrackStream[] allNewStreams) {
@@ -295,4 +359,18 @@ public final class HlsSampleSource implements SampleSource {
     throw new IndexOutOfBoundsException();
   }
 
+  private static boolean variantHasExplicitCodecWithPrefix(Variant variant, String prefix) {
+    String codecs = variant.codecs;
+    if (TextUtils.isEmpty(codecs)) {
+      return false;
+    }
+    String[] codecArray = codecs.split("(\\s*,\\s*)|(\\s*$)");
+    for (String codec : codecArray) {
+      if (codec.startsWith(prefix)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
 }

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

@@ -62,12 +62,14 @@ import java.util.List;
   private final ChunkHolder nextChunkHolder;
   private final EventDispatcher eventDispatcher;
   private final LoadControl loadControl;
+  private final Format muxedAudioFormat;
+  private final Format muxedCaptionFormat;
 
   private volatile boolean sampleQueuesBuilt;
 
   private boolean prepared;
   private boolean seenFirstTrackSelection;
-  private boolean notifyReset;
+  private boolean readingEnabled;
   private int enabledTrackCount;
   private Format downstreamFormat;
 
@@ -88,6 +90,10 @@ import java.util.List;
    * @param chunkSource A {@link HlsChunkSource} from which chunks to load are obtained.
    * @param loadControl Controls when the source is permitted to load data.
    * @param bufferSizeContribution The contribution of this source to the media buffer, in bytes.
+   * @param muxedAudioFormat If HLS master playlist indicates that the stream contains muxed audio,
+   *     this is the audio {@link Format} as defined by the playlist.
+   * @param muxedAudioFormat If HLS master playlist indicates that the stream contains muxed
+   *     captions, this is the audio {@link Format} as defined by the playlist.
    * @param eventHandler A handler to use when delivering events to {@code eventListener}. May be
    *     null if delivery of events is not required.
    * @param eventListener A listener of events. May be null if delivery of events is not required.
@@ -96,16 +102,20 @@ import java.util.List;
    *     before propagating an error.
    */
   public HlsTrackStreamWrapper(HlsChunkSource chunkSource, LoadControl loadControl,
-      int bufferSizeContribution, Handler eventHandler,
+      int bufferSizeContribution, Format muxedAudioFormat, Format muxedCaptionFormat,
-      ChunkTrackStreamEventListener eventListener, int eventSourceId, int minLoadableRetryCount) {
+      Handler eventHandler, ChunkTrackStreamEventListener eventListener, int eventSourceId,
+      int minLoadableRetryCount) {
     this.chunkSource = chunkSource;
     this.loadControl = loadControl;
     this.bufferSizeContribution = bufferSizeContribution;
+    this.muxedAudioFormat = muxedAudioFormat;
+    this.muxedCaptionFormat = muxedCaptionFormat;
     loader = new Loader("Loader:HlsTrackStreamWrapper", minLoadableRetryCount);
     eventDispatcher = new EventDispatcher(eventHandler, eventListener, eventSourceId);
     nextChunkHolder = new ChunkHolder();
     sampleQueues = new SparseArray<>();
     mediaChunks = new LinkedList<>();
+    readingEnabled = true;
     pendingResetPositionUs = C.UNSET_TIME_US;
   }
 
@@ -150,6 +160,10 @@ import java.util.List;
     return chunkSource.getDurationUs();
   }
 
+  public boolean isLive() {
+    return chunkSource.isLive();
+  }
+
   public TrackGroupArray getTrackGroups() {
     return trackGroups;
   }
@@ -211,12 +225,8 @@ import java.util.List;
     }
   }
 
-  public long readReset() {
+  public void setReadingEnabled(boolean readingEnabled) {
-    if (notifyReset) {
+    this.readingEnabled = readingEnabled;
-      notifyReset = false;
-      return lastSeekPositionUs;
-    }
-    return C.UNSET_TIME_US;
   }
 
   public long getBufferedPositionUs() {
@@ -265,7 +275,7 @@ import java.util.List;
   }
 
   /* package */ int readData(int group, FormatHolder formatHolder, DecoderInputBuffer buffer) {
-    if (notifyReset || isPendingReset()) {
+    if (!readingEnabled || isPendingReset()) {
       return TrackStream.NOTHING_READ;
     }
 
@@ -449,9 +459,9 @@ import java.util.List;
         Format trackFormat = null;
         if (primaryExtractorTrackType == PRIMARY_TYPE_VIDEO) {
           if (MimeTypes.isAudio(sampleFormat.sampleMimeType)) {
-            trackFormat = chunkSource.getMuxedAudioFormat();
+            trackFormat = muxedAudioFormat;
           } else if (MimeTypes.APPLICATION_EIA608.equals(sampleFormat.sampleMimeType)) {
-            trackFormat = chunkSource.getMuxedCaptionFormat();
+            trackFormat = muxedCaptionFormat;
           }
         }
         trackGroups[i] = new TrackGroup(getSampleFormat(trackFormat, sampleFormat));
@@ -494,32 +504,9 @@ import java.util.List;
    * @param positionUs The position to seek to.
    */
   private void seekToInternal(long positionUs) {
-    // Treat all seeks into non-seekable media as being to t=0.
-    positionUs = chunkSource.isLive() ? 0 : positionUs;
     lastSeekPositionUs = positionUs;
     downstreamPositionUs = positionUs;
-    notifyReset = true;
+    restartFrom(positionUs);
-    boolean seekInsideBuffer = !isPendingReset();
-    // TODO[REFACTOR]: This will nearly always fail to seek inside all buffers due to sparse tracks
-    // such as ID3 (probably EIA608 too). We need a way to not care if we can't seek to the keyframe
-    // before for such tracks. For ID3 we probably explicitly don't want the keyframe before, even
-    // if we do have it, since it might be quite a long way behind the seek position. We probably
-    // only want to output ID3 buffers whose timestamps are greater than or equal to positionUs.
-    int sampleQueueCount = sampleQueues.size();
-    for (int i = 0; seekInsideBuffer && i < sampleQueueCount; i++) {
-      if (groupEnabledStates[i]) {
-        seekInsideBuffer = sampleQueues.valueAt(i).skipToKeyframeBefore(positionUs);
-      }
-    }
-    if (seekInsideBuffer) {
-      while (mediaChunks.size() > 1 && mediaChunks.get(1).startTimeUs <= positionUs) {
-        mediaChunks.removeFirst();
-      }
-    } else {
-      // If we failed to seek within the sample queues, we need to restart.
-      chunkSource.seek();
-      restartFrom(positionUs);
-    }
   }
 
   private void discardSamplesForDisabledTracks() {