Changes around renderer readiness and extraction.

- Make MediaCodecTrackRenderer.isReady more permissive.
  This largely fixes #21
- Bring WebmExtractor closer to FragmentedMp4Extractor.
  The two will probably be placed under a common interface
  fairly soon, which will allow significant code
  deduplication.

library/src/main/java/com/google/android/exoplayer/FrameworkSampleSource.java

@@ -67,7 +67,7 @@ public final class FrameworkSampleSource implements SampleSource {
       extractor = new MediaExtractor();
       extractor.setDataSource(context, uri, headers);
       trackStates = new int[extractor.getTrackCount()];
-      pendingDiscontinuities = new boolean[extractor.getTrackCount()];
+      pendingDiscontinuities = new boolean[trackStates.length];
       trackInfos = new TrackInfo[trackStates.length];
       for (int i = 0; i < trackStates.length; i++) {
         android.media.MediaFormat format = extractor.getTrackFormat(i);
@@ -84,7 +84,7 @@ public final class FrameworkSampleSource implements SampleSource {
   @Override
   public int getTrackCount() {
     Assertions.checkState(prepared);
-    return extractor.getTrackCount();
+    return trackStates.length;
   }
 
   @Override
@@ -97,17 +97,18 @@ public final class FrameworkSampleSource implements SampleSource {
   public void enable(int track, long timeUs) {
     Assertions.checkState(prepared);
     Assertions.checkState(trackStates[track] == TRACK_STATE_DISABLED);
-    boolean wasSourceEnabled = isEnabled();
     trackStates[track] = TRACK_STATE_ENABLED;
     extractor.selectTrack(track);
-    if (!wasSourceEnabled) {
-      seekToUs(timeUs);
-    }
+    seekToUs(timeUs);
   }
 
   @Override
-  public void continueBuffering(long playbackPositionUs) {
-    // Do nothing. The MediaExtractor instance is responsible for buffering.
+  public boolean continueBuffering(long playbackPositionUs) {
+    // MediaExtractor takes care of buffering and blocks until it has samples, so we can always
+    // return true here. Although note that the blocking behavior is itself as bug, as per the
+    // TODO further up this file. This method will need to return something else as part of fixing
+    // the TODO.
+    return true;
   }
 
   @Override
@@ -122,15 +123,15 @@ public final class FrameworkSampleSource implements SampleSource {
     if (onlyReadDiscontinuity) {
       return NOTHING_READ;
     }
+    if (trackStates[track] != TRACK_STATE_FORMAT_SENT) {
+      formatHolder.format = MediaFormat.createFromFrameworkMediaFormatV16(
+          extractor.getTrackFormat(track));
+      formatHolder.drmInitData = Util.SDK_INT >= 18 ? getPsshInfoV18() : null;
+      trackStates[track] = TRACK_STATE_FORMAT_SENT;
+      return FORMAT_READ;
+    }
     int extractorTrackIndex = extractor.getSampleTrackIndex();
     if (extractorTrackIndex == track) {
-      if (trackStates[track] != TRACK_STATE_FORMAT_SENT) {
-        formatHolder.format = MediaFormat.createFromFrameworkMediaFormatV16(
-            extractor.getTrackFormat(track));
-        formatHolder.drmInitData = Util.SDK_INT >= 18 ? getPsshInfoV18() : null;
-        trackStates[track] = TRACK_STATE_FORMAT_SENT;
-        return FORMAT_READ;
-      }
       if (sampleHolder.data != null) {
         int offset = sampleHolder.data.position();
         sampleHolder.size = extractor.readSampleData(sampleHolder.data, offset);
@@ -202,13 +203,4 @@ public final class FrameworkSampleSource implements SampleSource {
     }
   }
 
-  private boolean isEnabled() {
-    for (int i = 0; i < trackStates.length; i++) {
-      if (trackStates[i] != TRACK_STATE_DISABLED) {
-        return true;
-      }
-    }
-    return false;
-  }
-
 }

library/src/main/java/com/google/android/exoplayer/MediaCodecAudioTrackRenderer.java

@@ -417,7 +417,7 @@ public class MediaCodecAudioTrackRenderer extends MediaCodecTrackRenderer {
 
   @Override
   protected boolean isReady() {
-    return getPendingFrameCount() > 0;
+    return super.isReady() || getPendingFrameCount() > 0;
   }
 
   /**

library/src/main/java/com/google/android/exoplayer/MediaCodecTrackRenderer.java

@@ -128,6 +128,7 @@ public abstract class MediaCodecTrackRenderer extends TrackRenderer {
   private int codecReconfigurationState;
 
   private int trackIndex;
+  private boolean sourceIsReady;
   private boolean inputStreamEnded;
   private boolean outputStreamEnded;
   private boolean waitingForKeys;
@@ -196,6 +197,7 @@ public abstract class MediaCodecTrackRenderer extends TrackRenderer {
   @Override
   protected void onEnabled(long timeUs, boolean joining) {
     source.enable(trackIndex, timeUs);
+    sourceIsReady = false;
     inputStreamEnded = false;
     outputStreamEnded = false;
     waitingForKeys = false;
@@ -346,6 +348,7 @@ public abstract class MediaCodecTrackRenderer extends TrackRenderer {
   protected void seekTo(long timeUs) throws ExoPlaybackException {
     currentPositionUs = timeUs;
     source.seekToUs(timeUs);
+    sourceIsReady = false;
     inputStreamEnded = false;
     outputStreamEnded = false;
     waitingForKeys = false;
@@ -364,7 +367,7 @@ public abstract class MediaCodecTrackRenderer extends TrackRenderer {
   @Override
   protected void doSomeWork(long timeUs) throws ExoPlaybackException {
     try {
-      source.continueBuffering(timeUs);
+      sourceIsReady = source.continueBuffering(timeUs);
       checkForDiscontinuity();
       if (format == null) {
         readFormat();
@@ -645,10 +648,7 @@ public abstract class MediaCodecTrackRenderer extends TrackRenderer {
   @Override
   protected boolean isReady() {
     return format != null && !waitingForKeys
-        && ((codec == null && !shouldInitCodec()) // We don't want the codec
-            || outputIndex >= 0 // Or we have an output buffer ready to release
-            || inputIndex < 0 // Or we don't have any input buffers to write to
-            || isWithinHotswapPeriod()); // Or the codec is being hotswapped
+        && (sourceIsReady || outputIndex >= 0 || isWithinHotswapPeriod());
   }
 
   private boolean isWithinHotswapPeriod() {

library/src/main/java/com/google/android/exoplayer/MediaCodecVideoTrackRenderer.java

@@ -235,7 +235,7 @@ public class MediaCodecVideoTrackRenderer extends MediaCodecTrackRenderer {
 
   @Override
   protected boolean isReady() {
-    if (super.isReady() && (renderedFirstFrame || !codecInitialized())) {
+    if (super.isReady()) {
       // Ready. If we were joining then we've now joined, so clear the joining deadline.
       joiningDeadlineUs = -1;
       return true;

library/src/main/java/com/google/android/exoplayer/SampleSource.java

@@ -102,8 +102,11 @@ public interface SampleSource {
    * Indicates to the source that it should still be buffering data.
    *
    * @param playbackPositionUs The current playback position.
+   * @return True if the source has available samples, or if the end of the stream has been reached.
+   *     False if more data needs to be buffered for samples to become available.
+   * @throws IOException If an error occurred reading from the source.
    */
-  public void continueBuffering(long playbackPositionUs);
+  public boolean continueBuffering(long playbackPositionUs) throws IOException;
 
   /**
    * Attempts to read either a sample, a new format or or a discontinuity from the source.

library/src/main/java/com/google/android/exoplayer/chunk/ChunkSampleSource.java

@@ -246,11 +246,21 @@ public class ChunkSampleSource implements SampleSource, Loader.Listener {
   }
 
   @Override
-  public void continueBuffering(long playbackPositionUs) {
+  public boolean continueBuffering(long playbackPositionUs) throws IOException {
     Assertions.checkState(state == STATE_ENABLED);
     downstreamPositionUs = playbackPositionUs;
     chunkSource.continueBuffering(playbackPositionUs);
     updateLoadControl();
+    if (isPendingReset() || mediaChunks.isEmpty()) {
+      return false;
+    } else if (mediaChunks.getFirst().sampleAvailable()) {
+      // There's a sample available to be read from the current chunk.
+      return true;
+    } else {
+      // It may be the case that the current chunk has been fully read but not yet discarded and
+      // that the next chunk has an available sample. Return true if so, otherwise false.
+      return mediaChunks.size() > 1 && mediaChunks.get(1).sampleAvailable();
+    }
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/chunk/MediaChunk.java

@@ -100,6 +100,14 @@ public abstract class MediaChunk extends Chunk {
   public abstract boolean prepare() throws ParserException;
 
   /**
+   * Returns whether the next sample is available.
+   *
+   * @return True if the next sample is available for reading. False otherwise.
+   * @throws ParserException
+   */
+  public abstract boolean sampleAvailable() throws ParserException;
+
+  /**
    * Reads the next media sample from the chunk.
    * <p>
    * Should only be called after the chunk has been successfully prepared.

library/src/main/java/com/google/android/exoplayer/chunk/Mp4MediaChunk.java

@@ -104,11 +104,18 @@ public final class Mp4MediaChunk extends MediaChunk {
   }
 
   @Override
+  public boolean sampleAvailable() throws ParserException {
+    NonBlockingInputStream inputStream = getNonBlockingInputStream();
+    int result = extractor.read(inputStream, null);
+    return (result & FragmentedMp4Extractor.RESULT_NEED_SAMPLE_HOLDER) != 0;
+  }
+
+  @Override
   public boolean read(SampleHolder holder) throws ParserException {
     NonBlockingInputStream inputStream = getNonBlockingInputStream();
     Assertions.checkState(inputStream != null);
     int result = extractor.read(inputStream, holder);
-    boolean sampleRead = (result & FragmentedMp4Extractor.RESULT_READ_SAMPLE_FULL) != 0;
+    boolean sampleRead = (result & FragmentedMp4Extractor.RESULT_READ_SAMPLE) != 0;
     if (sampleRead) {
       holder.timeUs -= sampleOffsetUs;
     }

library/src/main/java/com/google/android/exoplayer/chunk/SingleSampleMediaChunk.java

@@ -83,10 +83,15 @@ public class SingleSampleMediaChunk extends MediaChunk {
   }
 
   @Override
+  public boolean sampleAvailable() {
+    return isLoadFinished() && !isReadFinished();
+  }
+
+  @Override
   public boolean read(SampleHolder holder) {
     NonBlockingInputStream inputStream = getNonBlockingInputStream();
     Assertions.checkState(inputStream != null);
-    if (!isLoadFinished()) {
+    if (!sampleAvailable()) {
       return false;
     }
     int bytesLoaded = (int) bytesLoaded();

library/src/main/java/com/google/android/exoplayer/chunk/WebmMediaChunk.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer.chunk;
 
 import com.google.android.exoplayer.MediaFormat;
+import com.google.android.exoplayer.ParserException;
 import com.google.android.exoplayer.SampleHolder;
 import com.google.android.exoplayer.parser.webm.WebmExtractor;
 import com.google.android.exoplayer.upstream.DataSource;
@@ -70,10 +71,18 @@ public final class WebmMediaChunk extends MediaChunk {
   }
 
   @Override
+  public boolean sampleAvailable() throws ParserException {
+    NonBlockingInputStream inputStream = getNonBlockingInputStream();
+    int result = extractor.read(inputStream, null);
+    return (result & WebmExtractor.RESULT_NEED_SAMPLE_HOLDER) != 0;
+  }
+
+  @Override
   public boolean read(SampleHolder holder) {
     NonBlockingInputStream inputStream = getNonBlockingInputStream();
     Assertions.checkState(inputStream != null);
-    return extractor.read(inputStream, holder);
+    int result = extractor.read(inputStream, holder);
+    return (result & WebmExtractor.RESULT_READ_SAMPLE) != 0;
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/dash/DashMp4ChunkSource.java

@@ -146,7 +146,7 @@ public class DashMp4ChunkSource implements ChunkSource {
 
     RangedUri pendingInitializationUri = null;
     RangedUri pendingIndexUri = null;
-    if (extractor.getTrack() == null) {
+    if (extractor.getFormat() == null) {
       pendingInitializationUri = selectedRepresentation.getInitializationUri();
     }
     if (!segmentIndexes.containsKey(selectedRepresentation.format.id)) {
@@ -199,10 +199,10 @@ public class DashMp4ChunkSource implements ChunkSource {
     if (initializationUri != null) {
       // It's common for initialization and index data to be stored adjacently. Attempt to merge
       // the two requests together to request both at once.
-      expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_MOOV;
+      expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_INIT;
       requestUri = initializationUri.attemptMerge(indexUri);
       if (requestUri != null) {
-        expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_SIDX;
+        expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_INDEX;
         indexAnchor = indexUri.start + indexUri.length;
       } else {
         requestUri = initializationUri;
@@ -210,7 +210,7 @@ public class DashMp4ChunkSource implements ChunkSource {
     } else {
       requestUri = indexUri;
       indexAnchor = indexUri.start + indexUri.length;
-      expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_SIDX;
+      expectedExtractorResult |= FragmentedMp4Extractor.RESULT_READ_INDEX;
     }
     DataSpec dataSpec = new DataSpec(requestUri.getUri(), requestUri.start, requestUri.length,
         representation.getCacheKey());
@@ -256,9 +256,9 @@ public class DashMp4ChunkSource implements ChunkSource {
         throw new ParserException("Invalid extractor result. Expected "
             + expectedExtractorResult + ", got " + result);
       }
-      if ((result & FragmentedMp4Extractor.RESULT_READ_SIDX) != 0) {
+      if ((result & FragmentedMp4Extractor.RESULT_READ_INDEX) != 0) {
         segmentIndexes.put(format.id,
-            new DashWrappingSegmentIndex(extractor.getSegmentIndex(), uri, indexAnchor));
+            new DashWrappingSegmentIndex(extractor.getIndex(), uri, indexAnchor));
       }
     }
 

library/src/main/java/com/google/android/exoplayer/dash/DashWebmChunkSource.java

@@ -56,21 +56,26 @@ public class DashWebmChunkSource implements ChunkSource {
 
   private final Format[] formats;
   private final HashMap<String, Representation> representations;
-  private final HashMap<String, WebmExtractor> extractors;
+  private final HashMap<String, DefaultWebmExtractor> extractors;
   private final HashMap<String, DashSegmentIndex> segmentIndexes;
 
   private boolean lastChunkWasInitialization;
 
+  /**
+   * @param dataSource A {@link DataSource} suitable for loading the media data.
+   * @param evaluator Selects from the available formats.
+   * @param representations The representations to be considered by the source.
+   */
   public DashWebmChunkSource(DataSource dataSource, FormatEvaluator evaluator,
       Representation... representations) {
     this.dataSource = dataSource;
     this.evaluator = evaluator;
     this.formats = new Format[representations.length];
-    this.extractors = new HashMap<String, WebmExtractor>();
+    this.extractors = new HashMap<String, DefaultWebmExtractor>();
     this.segmentIndexes = new HashMap<String, DashSegmentIndex>();
     this.representations = new HashMap<String, Representation>();
-    this.trackInfo = new TrackInfo(
-        representations[0].format.mimeType, representations[0].periodDurationMs * 1000);
+    this.trackInfo = new TrackInfo(representations[0].format.mimeType,
+        representations[0].periodDurationMs * 1000);
     this.evaluation = new Evaluation();
     int maxWidth = 0;
     int maxHeight = 0;
@@ -109,7 +114,7 @@ public class DashWebmChunkSource implements ChunkSource {
 
   @Override
   public void disable(List<? extends MediaChunk> queue) {
-     evaluator.disable();
+    evaluator.disable();
   }
 
   @Override
@@ -140,13 +145,18 @@ public class DashWebmChunkSource implements ChunkSource {
     Representation selectedRepresentation = representations.get(selectedFormat.id);
     WebmExtractor extractor = extractors.get(selectedRepresentation.format.id);
 
-    if (!extractor.isPrepared()) {
-      // TODO: This code forces cues to exist and to immediately follow the initialization
-      // data. Webm extractor should be generalized to allow cues to be optional. See [redacted].
-      RangedUri initializationUri = selectedRepresentation.getInitializationUri().attemptMerge(
-           selectedRepresentation.getIndexUri());
-      Chunk initializationChunk = newInitializationChunk(initializationUri, selectedRepresentation,
-          extractor, dataSource, evaluation.trigger);
+    RangedUri pendingInitializationUri = null;
+    RangedUri pendingIndexUri = null;
+    if (extractor.getFormat() == null) {
+      pendingInitializationUri = selectedRepresentation.getInitializationUri();
+    }
+    if (!segmentIndexes.containsKey(selectedRepresentation.format.id)) {
+      pendingIndexUri = selectedRepresentation.getIndexUri();
+    }
+    if (pendingInitializationUri != null || pendingIndexUri != null) {
+      // We have initialization and/or index requests to make.
+      Chunk initializationChunk = newInitializationChunk(pendingInitializationUri, pendingIndexUri,
+          selectedRepresentation, extractor, dataSource, evaluation.trigger);
       lastChunkWasInitialization = true;
       out.chunk = initializationChunk;
       return;
@@ -181,12 +191,29 @@ public class DashWebmChunkSource implements ChunkSource {
     // Do nothing.
   }
 
-  private Chunk newInitializationChunk(RangedUri initializationUri, Representation representation,
-      WebmExtractor extractor, DataSource dataSource, int trigger) {
-    DataSpec dataSpec = new DataSpec(initializationUri.getUri(), initializationUri.start,
-        initializationUri.length, representation.getCacheKey());
+  private Chunk newInitializationChunk(RangedUri initializationUri, RangedUri indexUri,
+      Representation representation, WebmExtractor extractor, DataSource dataSource,
+      int trigger) {
+    int expectedExtractorResult = WebmExtractor.RESULT_END_OF_STREAM;
+    RangedUri requestUri;
+    if (initializationUri != null) {
+      // It's common for initialization and index data to be stored adjacently. Attempt to merge
+      // the two requests together to request both at once.
+      expectedExtractorResult |= WebmExtractor.RESULT_READ_INIT;
+      requestUri = initializationUri.attemptMerge(indexUri);
+      if (requestUri != null) {
+        expectedExtractorResult |= WebmExtractor.RESULT_READ_INDEX;
+      } else {
+        requestUri = initializationUri;
+      }
+    } else {
+      requestUri = indexUri;
+      expectedExtractorResult |= WebmExtractor.RESULT_READ_INDEX;
+    }
+    DataSpec dataSpec = new DataSpec(requestUri.getUri(), requestUri.start, requestUri.length,
+        representation.getCacheKey());
     return new InitializationWebmLoadable(dataSource, dataSpec, trigger, representation.format,
-        extractor);
+        extractor, expectedExtractorResult);
   }
 
   private Chunk newMediaChunk(Representation representation, DashSegmentIndex segmentIndex,
@@ -206,22 +233,27 @@ public class DashWebmChunkSource implements ChunkSource {
   private class InitializationWebmLoadable extends Chunk {
 
     private final WebmExtractor extractor;
+    private final int expectedExtractorResult;
     private final Uri uri;
 
     public InitializationWebmLoadable(DataSource dataSource, DataSpec dataSpec, int trigger,
-        Format format, WebmExtractor extractor) {
+        Format format, WebmExtractor extractor, int expectedExtractorResult) {
       super(dataSource, dataSpec, format, trigger);
       this.extractor = extractor;
+      this.expectedExtractorResult = expectedExtractorResult;
       this.uri = dataSpec.uri;
     }
 
     @Override
     protected void consumeStream(NonBlockingInputStream stream) throws IOException {
-      extractor.read(stream, null);
-      if (!extractor.isPrepared()) {
-        throw new ParserException("Invalid initialization data");
+      int result = extractor.read(stream, null);
+      if (result != expectedExtractorResult) {
+        throw new ParserException("Invalid extractor result. Expected "
+            + expectedExtractorResult + ", got " + result);
+      }
+      if ((result & WebmExtractor.RESULT_READ_INDEX) != 0) {
+        segmentIndexes.put(format.id, new DashWrappingSegmentIndex(extractor.getIndex(), uri, 0));
       }
-      segmentIndexes.put(format.id, new DashWrappingSegmentIndex(extractor.getCues(), uri, 0));
     }
 
   }

library/src/main/java/com/google/android/exoplayer/parser/webm/DefaultEbmlReader.java

@@ -138,9 +138,8 @@ import java.util.Stack;
     while (true) {
       while (!masterElementsStack.isEmpty()
           && bytesRead >= masterElementsStack.peek().elementEndOffsetBytes) {
-        if (!eventHandler.onMasterElementEnd(masterElementsStack.pop().elementId)) {
-          return READ_RESULT_CONTINUE;
-        }
+        eventHandler.onMasterElementEnd(masterElementsStack.pop().elementId);
+        return READ_RESULT_CONTINUE;
       }
 
       if (state == STATE_BEGIN_READING) {
@@ -161,12 +160,10 @@ import java.util.Stack;
         case TYPE_MASTER:
           int masterHeaderSize = (int) (bytesRead - elementOffset); // Header size is 12 bytes max.
           masterElementsStack.add(new MasterElement(elementId, bytesRead + elementContentSize));
-          if (!eventHandler.onMasterElementStart(
-              elementId, elementOffset, masterHeaderSize, elementContentSize)) {
-            prepareForNextElement();
-            return READ_RESULT_CONTINUE;
-          }
-          break;
+          eventHandler.onMasterElementStart(elementId, elementOffset, masterHeaderSize,
+              elementContentSize);
+          prepareForNextElement();
+          return READ_RESULT_CONTINUE;
         case TYPE_UNSIGNED_INT:
           if (elementContentSize > MAX_INTEGER_ELEMENT_SIZE_BYTES) {
             throw new IllegalStateException("Invalid integer size " + elementContentSize);
@@ -177,11 +174,9 @@ import java.util.Stack;
             return intResult;
           }
           long intValue = getTempByteArrayValue((int) elementContentSize, false);
-          if (!eventHandler.onIntegerElement(elementId, intValue)) {
-            prepareForNextElement();
-            return READ_RESULT_CONTINUE;
-          }
-          break;
+          eventHandler.onIntegerElement(elementId, intValue);
+          prepareForNextElement();
+          return READ_RESULT_CONTINUE;
         case TYPE_FLOAT:
           if (elementContentSize != VALID_FLOAT32_ELEMENT_SIZE_BYTES
               && elementContentSize != VALID_FLOAT64_ELEMENT_SIZE_BYTES) {
@@ -199,11 +194,9 @@ import java.util.Stack;
           } else {
             floatValue = Double.longBitsToDouble(valueBits);
           }
-          if (!eventHandler.onFloatElement(elementId, floatValue)) {
-            prepareForNextElement();
-            return READ_RESULT_CONTINUE;
-          }
-          break;
+          eventHandler.onFloatElement(elementId, floatValue);
+          prepareForNextElement();
+          return READ_RESULT_CONTINUE;
         case TYPE_STRING:
           if (elementContentSize > Integer.MAX_VALUE) {
             throw new IllegalStateException(
@@ -219,11 +212,9 @@ import java.util.Stack;
           }
           String stringValue = new String(stringBytes, Charset.forName("UTF-8"));
           stringBytes = null;
-          if (!eventHandler.onStringElement(elementId, stringValue)) {
-            prepareForNextElement();
-            return READ_RESULT_CONTINUE;
-          }
-          break;
+          eventHandler.onStringElement(elementId, stringValue);
+          prepareForNextElement();
+          return READ_RESULT_CONTINUE;
         case TYPE_BINARY:
           if (elementContentSize > Integer.MAX_VALUE) {
             throw new IllegalStateException(
@@ -233,18 +224,17 @@ import java.util.Stack;
             return READ_RESULT_NEED_MORE_DATA;
           }
           int binaryHeaderSize = (int) (bytesRead - elementOffset); // Header size is 12 bytes max.
-          boolean keepGoing = eventHandler.onBinaryElement(
+          boolean consumed = eventHandler.onBinaryElement(
               elementId, elementOffset, binaryHeaderSize, (int) elementContentSize, inputStream);
-          long expectedBytesRead = elementOffset + binaryHeaderSize + elementContentSize;
-          if (expectedBytesRead != bytesRead) {
-            throw new IllegalStateException("Incorrect total bytes read. Expected "
-                + expectedBytesRead + " but actually " + bytesRead);
-          }
-          if (!keepGoing) {
+          if (consumed) {
+            long expectedBytesRead = elementOffset + binaryHeaderSize + elementContentSize;
+            if (expectedBytesRead != bytesRead) {
+              throw new IllegalStateException("Incorrect total bytes read. Expected "
+                  + expectedBytesRead + " but actually " + bytesRead);
+            }
             prepareForNextElement();
-            return READ_RESULT_CONTINUE;
           }
-          break;
+          return READ_RESULT_CONTINUE;
         case TYPE_UNKNOWN:
           if (elementContentSize > Integer.MAX_VALUE) {
             throw new IllegalStateException(
@@ -254,11 +244,11 @@ import java.util.Stack;
           if (skipResult != READ_RESULT_CONTINUE) {
             return skipResult;
           }
+          prepareForNextElement();
           break;
         default:
           throw new IllegalStateException("Invalid element type " + type);
       }
-      prepareForNextElement();
     }
   }
 
@@ -508,7 +498,7 @@ import java.util.Stack;
    */
   private int updateBytesState(int additionalBytesRead, int totalBytes) {
     if (additionalBytesRead == -1) {
-      return READ_RESULT_END_OF_FILE;
+      return READ_RESULT_END_OF_STREAM;
     }
     bytesState += additionalBytesRead;
     bytesRead += additionalBytesRead;

library/src/main/java/com/google/android/exoplayer/parser/webm/DefaultWebmExtractor.java

@@ -25,6 +25,7 @@ import com.google.android.exoplayer.util.MimeTypes;
 import android.annotation.TargetApi;
 import android.media.MediaExtractor;
 
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.concurrent.TimeUnit;
 
@@ -77,11 +78,14 @@ public final class DefaultWebmExtractor implements WebmExtractor {
   private static final int LACING_FIXED = 2;
   private static final int LACING_EBML = 3;
 
+  private static final int READ_TERMINATING_RESULTS = RESULT_NEED_MORE_DATA | RESULT_END_OF_STREAM
+      | RESULT_READ_SAMPLE | RESULT_NEED_SAMPLE_HOLDER;
+
   private final EbmlReader reader;
   private final byte[] simpleBlockTimecodeAndFlags = new byte[3];
 
-  private SampleHolder tempSampleHolder;
-  private boolean sampleRead;
+  private SampleHolder sampleHolder;
+  private int readResults;
 
   private long segmentStartOffsetBytes = UNKNOWN;
   private long segmentEndOffsetBytes = UNKNOWN;
@@ -107,17 +111,19 @@ public final class DefaultWebmExtractor implements WebmExtractor {
   }
 
   @Override
-  public boolean isPrepared() {
-    return format != null && cues != null;
-  }
-
-  @Override
-  public boolean read(NonBlockingInputStream inputStream, SampleHolder sampleHolder) {
-    tempSampleHolder = sampleHolder;
-    sampleRead = false;
-    reader.read(inputStream);
-    tempSampleHolder = null;
-    return sampleRead;
+  public int read(NonBlockingInputStream inputStream, SampleHolder sampleHolder) {
+    this.sampleHolder = sampleHolder;
+    this.readResults = 0;
+    while ((readResults & READ_TERMINATING_RESULTS) == 0) {
+      int ebmlReadResult = reader.read(inputStream);
+      if (ebmlReadResult == EbmlReader.READ_RESULT_NEED_MORE_DATA) {
+        readResults |= WebmExtractor.RESULT_NEED_MORE_DATA;
+      } else if (ebmlReadResult == EbmlReader.READ_RESULT_END_OF_STREAM) {
+        readResults |= WebmExtractor.RESULT_END_OF_STREAM;
+      }
+    }
+    this.sampleHolder = null;
+    return readResults;
   }
 
   @Override
@@ -139,7 +145,7 @@ public final class DefaultWebmExtractor implements WebmExtractor {
   }
 
   @Override
-  public SegmentIndex getCues() {
+  public SegmentIndex getIndex() {
     return cues;
   }
 
@@ -288,6 +294,12 @@ public final class DefaultWebmExtractor implements WebmExtractor {
       // Please refer to http://www.matroska.org/technical/specs/index.html#simpleblock_structure
       // for info about how data is organized in a SimpleBlock element.
 
+      // If we don't have a sample holder then don't consume the data.
+      if (sampleHolder == null) {
+        readResults |= RESULT_NEED_SAMPLE_HOLDER;
+        return false;
+      }
+
       // Value of trackNumber is not used but needs to be read.
       reader.readVarint(inputStream);
 
@@ -309,10 +321,10 @@ public final class DefaultWebmExtractor implements WebmExtractor {
         case LACING_NONE:
           long elementEndOffsetBytes = elementOffsetBytes + headerSizeBytes + contentsSizeBytes;
           simpleBlockTimecodeUs = clusterTimecodeUs + timecodeUs;
-          tempSampleHolder.flags = keyframe ? MediaExtractor.SAMPLE_FLAG_SYNC : 0;
-          tempSampleHolder.decodeOnly = invisible;
-          tempSampleHolder.timeUs = clusterTimecodeUs + timecodeUs;
-          tempSampleHolder.size = (int) (elementEndOffsetBytes - reader.getBytesRead());
+          sampleHolder.flags = keyframe ? MediaExtractor.SAMPLE_FLAG_SYNC : 0;
+          sampleHolder.decodeOnly = invisible;
+          sampleHolder.timeUs = clusterTimecodeUs + timecodeUs;
+          sampleHolder.size = (int) (elementEndOffsetBytes - reader.getBytesRead());
           break;
         case LACING_EBML:
         case LACING_FIXED:
@@ -321,14 +333,22 @@ public final class DefaultWebmExtractor implements WebmExtractor {
           throw new IllegalStateException("Lacing mode " + lacing + " not supported");
       }
 
-      // Read video data into sample holder.
-      reader.readBytes(inputStream, tempSampleHolder.data, tempSampleHolder.size);
-      sampleRead = true;
-      return false;
-    } else {
-      reader.skipBytes(inputStream, contentsSizeBytes);
-      return true;
+      ByteBuffer outputData = sampleHolder.data;
+      if (sampleHolder.allowDataBufferReplacement
+          && (sampleHolder.data == null || sampleHolder.data.capacity() < sampleHolder.size)) {
+        outputData = ByteBuffer.allocate(sampleHolder.size);
+        sampleHolder.data = outputData;
+      }
+
+      if (outputData == null) {
+        reader.skipBytes(inputStream, sampleHolder.size);
+        sampleHolder.size = 0;
+      } else {
+        reader.readBytes(inputStream, outputData, sampleHolder.size);
+      }
+      readResults |= RESULT_READ_SAMPLE;
     }
+    return true;
   }
 
   private long scaleTimecodeToUs(long unscaledTimecode) {
@@ -347,6 +367,7 @@ public final class DefaultWebmExtractor implements WebmExtractor {
         && (format == null || format.width != pixelWidth || format.height != pixelHeight)) {
       format = MediaFormat.createVideoFormat(
           MimeTypes.VIDEO_VP9, MediaFormat.NO_VALUE, pixelWidth, pixelHeight, null);
+      readResults |= RESULT_READ_INIT;
     } else if (format == null) {
       throw new IllegalStateException("Unable to build format");
     }
@@ -387,6 +408,7 @@ public final class DefaultWebmExtractor implements WebmExtractor {
     cues = new SegmentIndex((int) cuesSizeBytes, sizes, offsets, durationsUs, timesUs);
     cueTimesUs = null;
     cueClusterPositions = null;
+    readResults |= RESULT_READ_INDEX;
   }
 
   /**
@@ -401,30 +423,30 @@ public final class DefaultWebmExtractor implements WebmExtractor {
     }
 
     @Override
-    public boolean onMasterElementStart(
+    public void onMasterElementStart(
         int id, long elementOffsetBytes, int headerSizeBytes, long contentsSizeBytes) {
-      return DefaultWebmExtractor.this.onMasterElementStart(
+      DefaultWebmExtractor.this.onMasterElementStart(
           id, elementOffsetBytes, headerSizeBytes, contentsSizeBytes);
     }
 
     @Override
-    public boolean onMasterElementEnd(int id) {
-      return DefaultWebmExtractor.this.onMasterElementEnd(id);
+    public void onMasterElementEnd(int id) {
+      DefaultWebmExtractor.this.onMasterElementEnd(id);
     }
 
     @Override
-    public boolean onIntegerElement(int id, long value) {
-      return DefaultWebmExtractor.this.onIntegerElement(id, value);
+    public void onIntegerElement(int id, long value) {
+      DefaultWebmExtractor.this.onIntegerElement(id, value);
     }
 
     @Override
-    public boolean onFloatElement(int id, double value) {
-      return DefaultWebmExtractor.this.onFloatElement(id, value);
+    public void onFloatElement(int id, double value) {
+      DefaultWebmExtractor.this.onFloatElement(id, value);
     }
 
     @Override
-    public boolean onStringElement(int id, String value) {
-      return DefaultWebmExtractor.this.onStringElement(id, value);
+    public void onStringElement(int id, String value) {
+      DefaultWebmExtractor.this.onStringElement(id, value);
     }
 
     @Override

library/src/main/java/com/google/android/exoplayer/parser/webm/EbmlEventHandler.java

@@ -46,9 +46,8 @@ import java.nio.ByteBuffer;
    * @param elementOffsetBytes The byte offset where this element starts
    * @param headerSizeBytes The byte length of this element's ID and size header
    * @param contentsSizeBytes The byte length of this element's children
-   * @return {@code false} if parsing should stop right away
    */
-  public boolean onMasterElementStart(
+  public void onMasterElementStart(
       int id, long elementOffsetBytes, int headerSizeBytes, long contentsSizeBytes);
 
   /**
@@ -56,44 +55,42 @@ import java.nio.ByteBuffer;
    * {@link NonBlockingInputStream}.
    *
    * @param id The integer ID of this element
-   * @return {@code false} if parsing should stop right away
    */
-  public boolean onMasterElementEnd(int id);
+  public void onMasterElementEnd(int id);
 
   /**
    * Called when an integer element is encountered in the {@link NonBlockingInputStream}.
    *
    * @param id The integer ID of this element
    * @param value The integer value this element contains
-   * @return {@code false} if parsing should stop right away
    */
-  public boolean onIntegerElement(int id, long value);
+  public void onIntegerElement(int id, long value);
 
   /**
    * Called when a float element is encountered in the {@link NonBlockingInputStream}.
    *
    * @param id The integer ID of this element
    * @param value The float value this element contains
-   * @return {@code false} if parsing should stop right away
    */
-  public boolean onFloatElement(int id, double value);
+  public void onFloatElement(int id, double value);
 
   /**
    * Called when a string element is encountered in the {@link NonBlockingInputStream}.
    *
    * @param id The integer ID of this element
    * @param value The string value this element contains
-   * @return {@code false} if parsing should stop right away
    */
-  public boolean onStringElement(int id, String value);
+  public void onStringElement(int id, String value);
 
   /**
    * Called when a binary element is encountered in the {@link NonBlockingInputStream}.
    *
    * <p>The element header (containing element ID and content size) will already have been read.
-   * Subclasses must exactly read the entire contents of the element, which is
-   * {@code contentsSizeBytes} in length. It's guaranteed that the full element contents will be
-   * immediately available from {@code inputStream}.
+   * Subclasses must either read nothing and return {@code false}, or exactly read the entire
+   * contents of the element, which is {@code contentsSizeBytes} in length, and return {@code true}.
+   *
+   * <p>It's guaranteed that the full element contents will be immediately available from
+   * {@code inputStream}.
    *
    * <p>Several methods in {@link EbmlReader} are available for reading the contents of a
    * binary element:
@@ -111,7 +108,7 @@ import java.nio.ByteBuffer;
    * @param contentsSizeBytes The byte length of this element's contents
    * @param inputStream The {@link NonBlockingInputStream} from which this
    *        element's contents should be read
-   * @return {@code false} if parsing should stop right away
+   * @return True if the element was read. False otherwise.
    */
   public boolean onBinaryElement(
       int id, long elementOffsetBytes, int headerSizeBytes, int contentsSizeBytes,

library/src/main/java/com/google/android/exoplayer/parser/webm/EbmlReader.java

@@ -44,12 +44,12 @@ import java.nio.ByteBuffer;
   // Return values for reading methods.
   public static final int READ_RESULT_CONTINUE = 0;
   public static final int READ_RESULT_NEED_MORE_DATA = 1;
-  public static final int READ_RESULT_END_OF_FILE = 2;
+  public static final int READ_RESULT_END_OF_STREAM = 2;
 
   public void setEventHandler(EbmlEventHandler eventHandler);
 
   /**
-   * Reads from a {@link NonBlockingInputStream} and calls event callbacks as needed.
+   * Reads from a {@link NonBlockingInputStream}, invoking an event callback if possible.
    *
    * @param inputStream The input stream from which data should be read
    * @return One of the {@code RESULT_*} flags defined in this interface

library/src/main/java/com/google/android/exoplayer/parser/webm/WebmExtractor.java

@@ -30,24 +30,38 @@ import com.google.android.exoplayer.upstream.NonBlockingInputStream;
 public interface WebmExtractor {
 
   /**
-   * Whether the has parsed the cues and sample format from the stream.
-   *
-   * @return True if the extractor is prepared. False otherwise
+   * An attempt to read from the input stream returned insufficient data.
+   */
+  public static final int RESULT_NEED_MORE_DATA = 1;
+  /**
+   * The end of the input stream was reached.
+   */
+  public static final int RESULT_END_OF_STREAM = 2;
+  /**
+   * A media sample was read.
+   */
+  public static final int RESULT_READ_SAMPLE = 4;
+  /**
+   * Initialization data was read. The parsed data can be read using {@link #getFormat()}.
+   */
+  public static final int RESULT_READ_INIT = 8;
+  /**
+   * A sidx atom was read. The parsed data can be read using {@link #getIndex()}.
    */
-  public boolean isPrepared();
+  public static final int RESULT_READ_INDEX = 16;
+  /**
+   * The next thing to be read is a sample, but a {@link SampleHolder} was not supplied.
+   */
+  public static final int RESULT_NEED_SAMPLE_HOLDER = 32;
 
   /**
    * Consumes data from a {@link NonBlockingInputStream}.
    *
-   * <p>If the return value is {@code false}, then a sample may have been partially read into
-   * {@code sampleHolder}. Hence the same {@link SampleHolder} instance must be passed
-   * in subsequent calls until the whole sample has been read.
-   *
    * @param inputStream The input stream from which data should be read
    * @param sampleHolder A {@link SampleHolder} into which the sample should be read
-   * @return {@code true} if a sample has been read into the sample holder
+   * @return One or more of the {@code RESULT_*} flags defined in this class.
    */
-  public boolean read(NonBlockingInputStream inputStream, SampleHolder sampleHolder);
+  public int read(NonBlockingInputStream inputStream, SampleHolder sampleHolder);
 
   /**
    * Seeks to a position before or equal to the requested time.
@@ -66,7 +80,7 @@ public interface WebmExtractor {
    * @return The cues in the form of a {@link SegmentIndex}, or null if the extractor is not yet
    *     prepared
    */
-  public SegmentIndex getCues();
+  public SegmentIndex getIndex();
 
   /**
    * Returns the format of the samples contained within the media stream.

library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java

@@ -144,7 +144,12 @@ public class TextTrackRenderer extends TrackRenderer implements Callback {
 
   @Override
   protected void doSomeWork(long timeUs) throws ExoPlaybackException {
-    source.continueBuffering(timeUs);
+    try {
+      source.continueBuffering(timeUs);
+    } catch (IOException e) {
+      throw new ExoPlaybackException(e);
+    }
+
     currentPositionUs = timeUs;
 
     // We're iterating through the events in a subtitle. Set textRendererNeedsUpdate if we advance