Parse TLEN duration in Mp3Extractor

Issue: #7949
PiperOrigin-RevId: 333733615

RELEASENOTES.md

@@ -14,6 +14,8 @@
 * Extractors:
  * Add support for .mp2 boxes in the `AtomParsers`
  ([#7967](https:/google/ExoPlayer/issues/7967)).
+ * Use TLEN ID3 tag to compute the duration in Mp3Extractor
+ ([#7949](https:/google/ExoPlayer/issues/7949)).
 
 ### 2.12.0 (2020-09-11) ###
 

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/mp3/MlltSeeker.java

@@ -29,9 +29,11 @@
  *
  * @param firstFramePosition The position of the start of the first frame in the stream.
  * @param mlltFrame The MLLT frame with seeking metadata.
+ * @param durationUs The stream duration in microseconds, or {@link C#TIME_UNSET} if it is
+ * unknown.
  * @return An {@link MlltSeeker} for seeking in the stream.
  */
- public static MlltSeeker create(long firstFramePosition, MlltFrame mlltFrame) {
+ public static MlltSeeker create(long firstFramePosition, MlltFrame mlltFrame, long durationUs) {
  int referenceCount = mlltFrame.bytesDeviations.length;
  long[] referencePositions = new long[1 + referenceCount];
  long[] referenceTimesMs = new long[1 + referenceCount];
@@ -45,19 +47,22 @@ public static MlltSeeker create(long firstFramePosition, MlltFrame mlltFrame) {
  referencePositions[i] = position;
  referenceTimesMs[i] = timeMs;
  }
- return new MlltSeeker(referencePositions, referenceTimesMs);
+ return new MlltSeeker(referencePositions, referenceTimesMs, durationUs);
  }
 
  private final long[] referencePositions;
  private final long[] referenceTimesMs;
  private final long durationUs;
 
- private MlltSeeker(long[] referencePositions, long[] referenceTimesMs) {
+ private MlltSeeker(long[] referencePositions, long[] referenceTimesMs, long durationUs) {
  this.referencePositions = referencePositions;
  this.referenceTimesMs = referenceTimesMs;
- // Use the last reference point as the duration, as extrapolating variable bitrate at the end of
- // the stream may give a large error.
- durationUs = C.msToUs(referenceTimesMs[referenceTimesMs.length - 1]);
+ // Use the last reference point as the duration if it is unknown, as extrapolating variable
+ // bitrate at the end of the stream may give a large error.
+ this.durationUs =
+ durationUs != C.TIME_UNSET
+ ? durationUs
+ : C.msToUs(referenceTimesMs[referenceTimesMs.length - 1]);
  }
 
  @Override

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/mp3/Mp3Extractor.java

@@ -35,6 +35,7 @@
 import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
 import com.google.android.exoplayer2.metadata.id3.Id3Decoder.FramePredicate;
 import com.google.android.exoplayer2.metadata.id3.MlltFrame;
+import com.google.android.exoplayer2.metadata.id3.TextInformationFrame;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
@@ -432,14 +433,16 @@ private Seeker computeSeeker(ExtractorInput input) throws IOException {
 
  @Nullable Seeker resultSeeker = null;
  if ((flags & FLAG_ENABLE_INDEX_SEEKING) != 0) {
- long durationUs = C.TIME_UNSET;
+ long durationUs;
  long dataEndPosition = C.POSITION_UNSET;
  if (metadataSeeker != null) {
  durationUs = metadataSeeker.getDurationUs();
  dataEndPosition = metadataSeeker.getDataEndPosition();
  } else if (seekFrameSeeker != null) {
  durationUs = seekFrameSeeker.getDurationUs();
  dataEndPosition = seekFrameSeeker.getDataEndPosition();
+ } else {
+ durationUs = getId3TlenUs(metadata);
  }
  resultSeeker =
  new IndexSeeker(
@@ -554,10 +557,24 @@ private static MlltSeeker maybeHandleSeekMetadata(
  for (int i = 0; i < length; i++) {
  Metadata.Entry entry = metadata.get(i);
  if (entry instanceof MlltFrame) {
- return MlltSeeker.create(firstFramePosition, (MlltFrame) entry);
+ return MlltSeeker.create(firstFramePosition, (MlltFrame) entry, getId3TlenUs(metadata));
  }
  }
  }
  return null;
  }
+
+ private static long getId3TlenUs(@Nullable Metadata metadata) {
+ if (metadata != null) {
+ int length = metadata.length();
+ for (int i = 0; i < length; i++) {
+ Metadata.Entry entry = metadata.get(i);
+ if (entry instanceof TextInformationFrame
+ && ((TextInformationFrame) entry).id.equals("TLEN")) {
+ return C.msToUs(Long.parseLong(((TextInformationFrame) entry).value));
+ }
+ }
+ }
+ return C.TIME_UNSET;
+ }
 }