Seeking to non-buffered position in 24bit 96kHz 6ch FLAC causes infinite buffering and playback stuck exception

[nift4]

Version

Media3 main branch

More version details

f672590

Devices that reproduce the issue

Google Pixel 7 Pro on Android 16 Beta 3.2 (BP22.250221.015)
Android 16 emulator

Devices that do not reproduce the issue

N/A

Reproducible in the demo app?

Yes

Reproduction steps

1. Play attached media in demo app from assets
2. Seek to some point in the middle of the file

Expected result

Buffering starts, eventually completes and playback continues

Actual result

After seeking, buffering never finishes, log is spamming with message before eventual timeout:

2025-04-10 18:34:36.667  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.677  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.687  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.698  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.708  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.719  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.729  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.740  6242-6315  DefaultLoadControl      androidx.media3.demo.main            W  Target buffer size reached with less than 500ms of buffered media data.
2025-04-10 18:34:36.741  6242-6315  ExoPlayerImplInternal   androidx.media3.demo.main            E  Playback error
                                                                                                      androidx.media3.exoplayer.ExoPlaybackException: Unexpected runtime error
                                                                                                          at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:895)
                                                                                                          at android.os.Handler.dispatchMessage(Handler.java:106)
                                                                                                          at android.os.Looper.loopOnce(Looper.java:248)
                                                                                                          at android.os.Looper.loop(Looper.java:338)
                                                                                                          at android.os.HandlerThread.run(HandlerThread.java:85)
                                                                                                      Caused by: java.lang.IllegalStateException: Playback stuck buffering and not loading
                                                                                                          at androidx.media3.exoplayer.ExoPlayerImplInternal.doSomeWork(ExoPlayerImplInternal.java:1428)
                                                                                                          at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:684)
                                                                                                          at android.os.Handler.dispatchMessage(Handler.java:106) 
                                                                                                          at android.os.Looper.loopOnce(Looper.java:248) 
                                                                                                          at android.os.Looper.loop(Looper.java:338) 
                                                                                                          at android.os.HandlerThread.run(HandlerThread.java:85)

Media

https://temp.nift4.org/testfile2.flac

Bug report ZIP:

bugreport-sdk_gphone64_arm64-BP22.250221.010-2025-04-10-18-34-40.zip

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.

[nift4]

@icbaker gentle ping to avoid this drowning in backlog

[icbaker]

I can reproduce the behaviour you observe.

The provided file has a seek table, but it is empty. You can see this in the output of metaflac --list:

METADATA block #1
  type: 3 (SEEKTABLE)
  is last: false
  length: 0
  seek points: 0

The presence of this means ExoPlayer marks the file as seekable using this seek table here:

media/libraries/extractor/src/main/java/androidx/media3/extractor/flac/FlacExtractor.java

Lines 330 to 342 in 839de45

	private SeekMap getSeekMap(long firstFramePosition, long streamLength) {
	Assertions.checkNotNull(flacStreamMetadata);
	if (flacStreamMetadata.seekTable != null) {
	return new FlacSeekTableSeekMap(flacStreamMetadata, firstFramePosition);
	} else if (streamLength != C.LENGTH_UNSET && flacStreamMetadata.totalSamples > 0) {
	binarySearchSeeker =
	new FlacBinarySearchSeeker(
	flacStreamMetadata, frameStartMarker, firstFramePosition, streamLength);
	return binarySearchSeeker.getSeekMap();
	} else {
	return new SeekMap.Unseekable(flacStreamMetadata.getDurationUs());
	}
	}

If the seek table was completely absent, we would fall back to doing binary search seeking instead.

If I change the check to ignore empty seek tables, then this file is now seekable without failing. I'll send this change for review.

if (flacStreamMetadata.seekTable != null
    && flacStreamMetadata.seekTable.pointSampleNumbers.length > 0) {
  return new FlacSeekTableSeekMap(flacStreamMetadata, firstFramePosition);
} else if ...

[icbaker]

This is fixed by e0ce5ed

[nift4]

Thanks :)