Choppy audio playback for some m4a's

Hi ExoPlayer team,

I’ve had user reports of choppy audio for a couple of songs. They’ve sent me the tracks, which I’ll attach here. Unfortunately they’re extremely awful to listen to even without playback issues.

Easy to replicate. Listen to either song and you should notice the ‘choppy’ sound.

I can replicate the issue on my Pixel 5 running Android 11. I see the following in the logs:

W/C2SoftAacDec: AAC decoder returned error 0x4004, substituting silence
W/C2SoftAacDec: aacDecoder_DecodeFrame decoderErr = 0x4004

These lines are consistently output while playing the files.

I’ve reproduced the issue in ExoPlayer 2.14.1.

I reckon there’s probably a good chance that the file is corrupt, or incorrectly encoded - but I don’t possess the skills to verify this. According to user reports, these play OK using other apps (so probably using the Android MediaPlayer).

I tested in VLC and playback seems OK.

Sincere apologies to anyone who has to listen to the audio. songs.zip

[ojw28]

The issue seems to be fixed on Pixel running Android 12. I’m following up to try and understand what the fix was, and whether it will be deployed to Android 11 devices (for those devices that are not updated quickly, or will have Android 11 as their final major release).

[ojw28]

I’m not sure what’s going wrong here, but I’ve filed an internal issue on those responsible for the AAC decoder to take an initial look [Internal ref: 191123693]. I’ll provide an update when we hear back.

Sincere apologies to anyone who has to listen to the audio.

Heh 😃