Noise when playing FLAC content

[tomislavturcic]

Question

Initially this was opened as a bug here, but after much further investigation, it appears to be an error on my client or server side.
Using ConcatenatingMedia and a MediaSources which are a mix of 16bit and 24bit music tracks, static and noise appear when switching from certain 24bit sources to 16bit sources. This happens when switching from 44.1KHz/24bit source to any 16bit source.
During the static, following error is repeatedly logged:
AudioTrack: Discontinuity detected [expected 'some value', got 'some other valuej']

I've found out that LibflacAudioRenderer returns FORMAT_UNSUPPORTED_TYPE when supportsFormatInternal method is called. That is because format.sampleMimeType is "audio/raw". Therefore FlacDecoder is never created. Any advice?

And for additional info, here's my ExoPlayer construction:

SimpleExoPlayer exoPlayer = ExoPlayerFactory.newSimpleInstance(context, 
                createRenderersFactory(context), 
                new DefaultTrackSelector());
DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(context, Util.getUserAgent(context, "ExoPlayerTest"));

Creating RenderersFactory instance. (I've tried various options here, all lead to same results).

private RenderersFactory createRenderersFactory(Context context) {
        DefaultRenderersFactory factory = new DefaultRenderersFactory(context);
        factory.setExtensionRendererMode(DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER);
        return factory;
}

Creating MediaSources for ConcatenatingMediaSource:

private MediaSource createMediaSource(PlayerTrack track) {
        return new ProgressiveMediaSource.Factory(dataSourceFactory)
                .setTag(track)
                .createMediaSource(Uri.parse(track.url));
}

EDIT:
Playback is normal when I downgrade to 2.9.x ExoPlayer. So perhaps this really is a bug. Any way to make this work on Exo 2.10.x ?

EDIT2:
I am also unable to build FLAC libs on 2.10.6 version.

A full bug report captured from the device

logcat.txt

Link to test content

Test content sent to dev.exoplayer@gmail.com.

[herintsoaRazaf]

I'm facing the same issue after an update of Exoplayer to 2.10.5 version.

[andrewlewis]

I've found out that LibflacAudioRenderer returns FORMAT_UNSUPPORTED_TYPE when supportsFormatInternal method is called. That is because format.sampleMimeType is "audio/raw". Therefore FlacDecoder is never created. Any advice?

I think this part is working as intended assuming you are playing audio in a .flac container file. FlacExtractor outputs PCM because of the way the file is structured. (LibflacAudioRenderer is needed for decoding FLAC without using a platform decoder where the audio comes from another container like Matroska.)

I am also unable to build FLAC libs on 2.10.6 version.

Looks like we need to switch to NDK 20, which also requires using c++_static not gnustl_static. I will make the fix.

Playback is normal when I downgrade to 2.9.x ExoPlayer. So perhaps this really is a bug. Any way to make this work on Exo 2.10.x ?

Still investigating this.

[kgrevehagen]

Look at this comment in #6608 for a potential cause and fix for the one you are still investigating.

[andrewlewis]

As mentioned in #6608: I think the issue is probably that the audio sink is not reconfigured despite the PCM bit depth changing. When I was fixing this I uncovered another issue with draining audio processors which I'm looking into at the moment (this additional issue prevents this working even with a fix not to keep the codec).

[ojw28]

This should be fixed in the dev-v2 and dev-v2-r2.11.0 branches.