Multichannel tracks render TV devices unable to play stereo tracks

[branches78]

Version

Media3 main branch

More version details

First of all, I don't know what version to choose so I selected "Media3 main branch".

Second, I am not a developer so I am unable to build the demo app.

Third, the following issue is a widespread issue.

I discovered the issue on Jellyfin by the end of last year but I though it was an issue exclusive to that app, however, I was able to find it out on other apps.

When I play a multichannel audio track (usually FLAC) with 5.1 or 7.1 channels from ANY Android for TV device connected to a multichannel AV receiver, the apps I tested play it correctly, no issue here.

The problem lies when I attempt to play an stereo track after I played a multichannel track, where the device is unable to output sound while the song is playing and the issue affects any app installed on the device, for example, audio is not output from YouTube anymore.

If I play again the multichannel track, sound outputs with no issue.

The issue can be “fixed” depending on the device:

On devices with a passthrough audio option (such as the Homatics Box R 4K Plus), I have to reboot the device to fix it.

On devices where the Dolby MS12 software stack is permanent (such as the Google TV Streamer), the issue doesn't happen apparently or it could be random.

Let me know if a log file from the app I tested could be useful for you as I can't build the demo app.

Devices that reproduce the issue

Any Android for TV device with a passthrough audio option but I'm can't confirm if versions older than Android 14 are affected.

Devices that do not reproduce the issue

Android for TV devices where the Dolby MS12 software stack is permanent.

Reproducible in the demo app?

Not tested

Reproduction steps

1. Open the music player app, for example Symfonium which is available for TV.
2. Play an stereo track first, it will play with no issues.
3. Play a multichannel track, it will play with no issues.
4. Play again an stereo track, the app will play the track but no audio is output.
5. To fix the issue, I have to reboot the device otherwise I won't be able to play any stereo track from other apps such as YouTube.

Expected result

Any app that uses Exoplayer should switch seamlessly from the stereo track to the multichannel track and viceversa without audio issues, this was working correctly before but I ignore on what version of Exoplayer the issue started to happen.

Actual result

As explained above, there is no audio output when I attempt to play an stereo track after playing a multichannel track on all apps affected.

Media

You can use this sample.

Bug Report

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

[microkatz]

Hello @branches78

Thank you for reporting your issue! A few of questions.

1. I know you are not able to build the demo app, but it would really help if you tried! The reason is that it would really help in this scenario to grab a bug report. It could help us see if the AudioTrack is getting reinitialized, what the configurations are etc. as well as logs from the Android framework.
2. Does the problem go away if you restart the app or only if you restart the device? If you kill an app but the problem persists, seems like an issue in the Android Framework or device-specific issue.
3. Could you please provide a media sample that is usable by ExoPlayer? Perhaps an mkv file or streamable link instead of that .rar file?

If you're unable to share bug reports or test content publicly, please send them to android-media-github@google.com with the subject Issue #3339. Please also update this issue to indicate you've done this.

[branches78]

Hello @microkatz

1. I wish I could, I will have to learn how to do it myself 🤷‍♂️
2. As I explained above, the only fix is to reboot the device, force-stopping the app doesn't fix the issue.
3. The issue doesn't happen with videos, it only happens with standalone audio files on any codec (PCM, FLAC, AAC, Opus) played on music player apps, such as the one I've been using (Symfonium), the RAR file contains those standalone audio files but if you need a link where you can stream one file directly, please let me know if you can do it from this link: Bob Marley & The Wailers - Buffalo Soldier.flac

[microkatz]

@branches78

Thank you for the response!

Another question, have you found this to occur on multiple devices? Or just the Homatics Box R 4K Plus?

A bug report would be most useful and here is a link providing info on how to collect one.

From my current point of view, this would appear to be a device-specific or android framework issue rather than an ExoPlayer bug. You noted that you have to restart the device rather than kill the app. If its an android framework-level issue then we can try to route the bug internally and a bug report would be most helpful for that! If its a device-specific issue then you might also want to reach out to the manufacturer.

[branches78]

Hello @microkatz

have you found this to occur on multiple devices? Or just the Homatics Box R 4K Plus?

It appears the issue happens on devices with a passthrough audio option, I've been trying to reproduce the issue on devices where the Dolby MS12 software stack is permanent such as the Google TV Streamer but it seems to be random, I will let you know if it happens. I don't have another device with a passthrough option at the moment but I will try to find one from the people I know.

A bug report would be most useful

I collected one from the device, I hope it doesn't contain personal information:

bugreport-SEI804HM-UKG3.250803.001-2026-07-22-10-01-07.zip

this would appear to be a device-specific or android framework issue rather than an ExoPlayer bug

Please let me know if that's the case based on the bug report above so I can report this to the OEM.

[branches78]

I forgot to mention that I extracted the bug report while the issue was being reproduced.

[microkatz]

@branches78

Thank you for the bug report!

I have created a bug internally(b/538141922 for reference) with the Android Audio team.

I'll see if they have any additional insight.

[branches78]

Hello @microkatz

I managed to build the demo (a friend who is a developer helped me 🤣) and it's already installed on my device but I don't see multichannel and stereo audio tracks (not videos) available in the app to test, can you please clarify what should I play from the app so I can gather a log?

[See61]

Tested on behalf of branches and indeed, replay bug is confirmed. I will report to Homatics (SEI Robotics) as I'm part of their Alpha firmware testers.
Device tested on; Dune Premier HD Pro, also a SEI804 device, which the (Dune) Homatics R Plus also is.
Tested with most recent firmware we got, V14 build 8963. Google certified build.

To add as exception that has no issue with playing multichannel and stereo files after each other. The Dune Media Center app, available as app only on the Dune devices with Certified Android TV, plays these correctly, with sound, as it should be.

Let there be some knowledge exchange between SEI and Dune development about this, as both are using the exact same firmware on the Dune and Homatics devices.