Support mp3 media segments in HLS.

Issue #804

library/src/main/java/com/google/android/exoplayer/extractor/mp3/Mp3Extractor.java

@@ -48,6 +48,7 @@ public final class Mp3Extractor implements Extractor {
   private static final int INFO_HEADER = Util.getIntegerCodeForString("Info");
   private static final int VBRI_HEADER = Util.getIntegerCodeForString("VBRI");
 
+  private final long forcedFirstSampleTimestampUs;
   private final BufferingInput inputBuffer;
   private final ParsableByteArray scratch;
   private final MpegAudioHeader synchronizedHeader;
@@ -63,11 +64,25 @@ public final class Mp3Extractor implements Extractor {
   private int samplesRead;
   private int sampleBytesRemaining;
 
-  /** Constructs a new {@link Mp3Extractor}. */
+  /**
+   * Constructs a new {@link Mp3Extractor}.
+   */
   public Mp3Extractor() {
+    this(-1);
+  }
+
+  /**
+   * Constructs a new {@link Mp3Extractor}.
+   *
+   * @param forcedFirstSampleTimestampUs A timestamp to force for the first sample, or -1 if forcing
+   *     is not required.
+   */
+  public Mp3Extractor(long forcedFirstSampleTimestampUs) {
+    this.forcedFirstSampleTimestampUs = forcedFirstSampleTimestampUs;
     inputBuffer = new BufferingInput(MpegAudioHeader.MAX_FRAME_SIZE_BYTES * 3);
     scratch = new ParsableByteArray(4);
     synchronizedHeader = new MpegAudioHeader();
+    basisTimeUs = -1;
   }
 
   @Override
@@ -164,6 +179,10 @@ public final class Mp3Extractor implements Extractor {
       }
       if (basisTimeUs == -1) {
         basisTimeUs = seeker.getTimeUs(getPosition(extractorInput, inputBuffer));
+        if (forcedFirstSampleTimestampUs != -1) {
+          long embeddedFirstSampleTimestampUs = seeker.getTimeUs(0);
+          basisTimeUs += forcedFirstSampleTimestampUs - embeddedFirstSampleTimestampUs;
+        }
       }
       sampleBytesRemaining = synchronizedHeader.frameSize;
     }

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

@@ -23,6 +23,7 @@ import com.google.android.exoplayer.chunk.ChunkOperationHolder;
 import com.google.android.exoplayer.chunk.DataChunk;
 import com.google.android.exoplayer.chunk.Format;
 import com.google.android.exoplayer.extractor.Extractor;
+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;
@@ -114,6 +115,7 @@ public class HlsChunkSource {
 
   private static final String TAG = "HlsChunkSource";
   private static final String AAC_FILE_EXTENSION = ".aac";
+  private static final String MP3_FILE_EXTENSION = ".mp3";
   private static final float BANDWIDTH_FRACTION = 0.8f;
 
   private final DataSource dataSource;
@@ -354,24 +356,28 @@ public class HlsChunkSource {
 
     // Configure the extractor that will read the chunk.
     HlsExtractorWrapper extractorWrapper;
-
-    if (previousTsChunk == null || segment.discontinuity || liveDiscontinuity
+    if (chunkUri.getLastPathSegment().endsWith(AAC_FILE_EXTENSION)) {
+      Extractor extractor = new AdtsExtractor(startTimeUs);
+      extractorWrapper = new HlsExtractorWrapper(trigger, format, startTimeUs, extractor,
+          switchingVariantSpliced, adaptiveMaxWidth, adaptiveMaxHeight);
+    } else if (chunkUri.getLastPathSegment().endsWith(MP3_FILE_EXTENSION)) {
+      Extractor extractor = new Mp3Extractor(startTimeUs);
+      extractorWrapper = new HlsExtractorWrapper(trigger, format, startTimeUs, extractor,
+          switchingVariantSpliced, adaptiveMaxWidth, adaptiveMaxHeight);
+    } else if (previousTsChunk == null || segment.discontinuity || liveDiscontinuity
         || !format.equals(previousTsChunk.format)) {
-      Extractor extractor;
-      if (chunkUri.getLastPathSegment().endsWith(AAC_FILE_EXTENSION)) {
-        extractor = new AdtsExtractor(startTimeUs);
-      } else {
-        if (previousTsChunk == null || segment.discontinuity || liveDiscontinuity
-            || ptsTimestampAdjuster == null) {
-          // TODO: Use this for AAC as well, along with the ID3 PRIV priv tag values with owner
-          // identifier com.apple.streaming.transportStreamTimestamp.
-          ptsTimestampAdjuster = new PtsTimestampAdjuster(startTimeUs);
-        }
-        extractor = new TsExtractor(ptsTimestampAdjuster);
+      // MPEG-2 TS segments, but we need a new extractor.
+      if (previousTsChunk == null || segment.discontinuity || liveDiscontinuity
+          || ptsTimestampAdjuster == null) {
+        // TODO: Use this for AAC as well, along with the ID3 PRIV priv tag values with owner
+        // identifier com.apple.streaming.transportStreamTimestamp.
+        ptsTimestampAdjuster = new PtsTimestampAdjuster(startTimeUs);
       }
+      Extractor extractor = new TsExtractor(ptsTimestampAdjuster);
       extractorWrapper = new HlsExtractorWrapper(trigger, format, startTimeUs, extractor,
           switchingVariantSpliced, adaptiveMaxWidth, adaptiveMaxHeight);
     } else {
+      // MPEG-2 TS segments, and we need to continue using the same extractor.
       extractorWrapper = previousTsChunk.extractorWrapper;
     }
 

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

@@ -131,24 +131,30 @@ public final class HlsSampleSource implements SampleSource, SampleSourceReader,
       return true;
     }
     if (!extractors.isEmpty()) {
-      // We're not prepared, but we might have loaded what we need.
-      HlsExtractorWrapper extractor = getCurrentExtractor();
-      if (extractor.isPrepared()) {
-        trackCount = extractor.getTrackCount();
-        trackEnabledStates = new boolean[trackCount];
-        pendingDiscontinuities = new boolean[trackCount];
-        downstreamMediaFormats = new MediaFormat[trackCount];
-        trackFormat = new MediaFormat[trackCount];
-        long durationUs = chunkSource.getDurationUs();
-        for (int i = 0; i < trackCount; i++) {
-          MediaFormat format = extractor.getMediaFormat(i).copyWithDurationUs(durationUs);
-          if (MimeTypes.isVideo(format.mimeType)) {
-            format = format.copyAsAdaptive();
+      while (true) {
+        // We're not prepared, but we might have loaded what we need.
+        HlsExtractorWrapper extractor = extractors.getFirst();
+        if (extractor.isPrepared()) {
+          trackCount = extractor.getTrackCount();
+          trackEnabledStates = new boolean[trackCount];
+          pendingDiscontinuities = new boolean[trackCount];
+          downstreamMediaFormats = new MediaFormat[trackCount];
+          trackFormat = new MediaFormat[trackCount];
+          long durationUs = chunkSource.getDurationUs();
+          for (int i = 0; i < trackCount; i++) {
+            MediaFormat format = extractor.getMediaFormat(i).copyWithDurationUs(durationUs);
+            if (MimeTypes.isVideo(format.mimeType)) {
+              format = format.copyAsAdaptive();
+            }
+            trackFormat[i] = format;
           }
-          trackFormat[i] = format;
+          prepared = true;
+          return true;
+        } else if (extractors.size() > 1) {
+          extractors.removeFirst().clear();
+        } else {
+          break;
         }
-        prepared = true;
-        return true;
       }
     }
     // We're not prepared and we haven't loaded what we need.