Killing the app while audio is playing results in "The controller is not connected" and not being able to play again

[k-arabadzhiev]

Version

Media3 1.2.0

More version details

No response

Devices that reproduce the issue

• OnePlus 7T Pro - Android 11
• Pixel 4 Emulator - Api 33

Devices that do not reproduce the issue

No response

Reproducible in the demo app?

Not tested

Reproduction steps

1. Open app and play audio
2. Kill the app (swipe from recents)
3. Reopen the app and try to play audio again

Expected result

The audio should play normmally

Actual result

Audio doesn't play.
Logs:

MediaController      The controller is not connected. Ignoring setMediaItem().
MediaController      The controller is not connected. Ignoring prepare().

If the app is killed a second time, then the audio will play normally. However the issue can be reproduced again.

Media

Not applicable

Bug Report

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

[k-arabadzhiev]

A bit more context.

Our app has been migrating to media3 for some time now and we are facing a weird issue with MusicServiceConnection when using dagger2 singleton injection.
I'm not absolutely certain that the issue is in media3, but it wasn't happening with androidx.media that we had previously.
Also I was able to reproduce the issue (to some degree) using UAMP and I'll explain the differences with our app as in depth as I can.

The issue

Killing the app (swipe from recents) while audio is playing, reopening and trying to play again will result in audio not being able to start.

Here is what I found in the logs on the second app launch:

MediaController      The controller is not connected. Ignoring setMediaItem().
MediaController      The controller is not connected. Ignoring prepare().

Killing the app a second time, reopening and trying to play will work.

Pausing the app manually (from the app itself or notification player) before killing it will not cause the issue.
However, pausing the player in code (in onTaskRemoved for example) will not solve the issue.

The workaround that we're currently using is to not use dagger's singleton scope, but instead instantiate the MusicServiceConnection using companion object like it's done in UAMP

Here is my fork of UAMP where I've reproduced the issue. In this branch a lot of libraries are updated, including media3 and dagger2 dependency injection is implemented as well.

UAMP is architecturally very different from our app, because the whole UI depends on the root media item. So after killing the app while the audio is playing the result will be that the UI is not even rendering. I think that's the reason I can't see in the logs The controller is not connected - because I can't even get to play anything, but the root cause of the issue should be the same.

Any idea why is this happening? Why singleton injection doesn't work, but the companion object snippet that looks like a hack is working?

[marcbaechinger]

Difficult to say with the available information.

Can you add an EventLogger to the player and then do a bug report after you went through the repro process of 1) starting the app, 2) swiping from recent tasks while playing 3) restart the app that produces the controller not connected logs then 4) pausing the player and swipe away and 5) restarting to play again?

It would also be interesting to see what adb shell dumpsys media_session gives you after 2) and before 3).

[k-arabadzhiev]

Hello @marcbaechinger
I've sent an email to android-media-github@google.com that includes the bugreport and also shell dumpsys media_session.

Also I've noticed something in logcat, that I'm not sure will be obvious in the bug report, but might be worth mentioning. It's in the email as well, but I'm including it here as it doesn't contain sensitive information and might be useful to someone coming to this issue in the future.

For brevity, let's separate the steps from Marc's comment in 2 different scenarios.

Scenario 1 (results in audio not playing)

1. Start the app and play audio
2. Swipe from recents while playing
3. Reopen the app and playing again doesn't work (controller not connected)
4. Swipe from recents again
5. Reopen the app and playing will work

To keep everything clean and consistent, I'm starting with force closed app.
Logs:

---------------------------- PROCESS STARTED (9502) for package com.example.app ---------------------------- // step 1
---------------------------- PROCESS ENDED (9502) for package com.example.app ---------------------------- // step 4, doesn't happen after step 2 for some reason
---------------------------- PROCESS STARTED (9902) for package com.example.app ---------------------------- // step 5

Scenario 2 (results in audio playing)

1. Start the app and play audio
2. Pause the audio
3. Swipe from recents
4. Reopen the app and playing will work

Logs:

---------------------------- PROCESS STARTED (9134) for package com.example.app ---------------------------- // step 1
---------------------------- PROCESS ENDED (9134) for package com.example.app ---------------------------- // step 3
---------------------------- PROCESS STARTED (10319) for package com.example.app ---------------------------- // happens automatically few seconds after 3

[marcbaechinger]

Thanks. Just checking. In the case that the player is not paused, you pause it in onTaskRemoved before calling stopSelf as documented here (see code snippets there)?

Because from what you are posting it looks that the app isn't terminated as you expect.

[k-arabadzhiev]

I'm doing it the same way as UAMP in media3 branch. I've also tried to use player.pause() before releasing it (line 243), but doesn't seem to make a difference.

I just tried with the snippets you've provided. Here is how my code looks like now:

   override fun onTaskRemoved(rootIntent: Intent) {
        Timber.tag(TAG).d("onTaskRemoved")
        super.onTaskRemoved(rootIntent)

        val player = mediaSession.player
        if (player.playWhenReady) {
            Timber.tag(TAG).d("player paused")
            player.pause()
        }
        stopSelf()
    }

    override fun onDestroy() {
        releaseMediaSession()
        Timber.tag(TAG).d("onDestroy")
        super.onDestroy()
    }

    private fun releaseMediaSession() {
        mediaSession.run {
            player.release()
            release()
            Timber.tag(TAG).d("mediasession released")
        }
        serviceJob.cancel()
    }

Scenario 1 logs:

---------------------------- PROCESS STARTED (28214) for package com.example.app ----------------------------
15:03:13.269 28214-28214                      onCreate
15:03:20.351 28214-28214                      onTaskRemoved
15:03:20.351 28214-28214                      player paused

At this point we're at step 2 and the app has been swiped away. However, because the media session hasn't been released, the notification player remains. Playing from it seems to be working as well. If I reopen the app and play again it will also work, but we have a requirement to remove the notification player when app is killed (we don't support playback resumption yet). Also I'm not sure why neither onDestroy nor "PROCESS ENDED" are called. For the former, I'm assuming it's because the session hasn't been released.
In UAMP (and also my code before trying these snippets) there's a call to releaseMediaSession before stopSelf(). If this call is present, then onDestroy does get called for this scenario.

Scenario 2 logs:

---------------------------- PROCESS STARTED (28705) for package com.example.app ----------------------------
15:06:34.156 28705-28705                      onCreate
15:06:42.985 28705-28705                      onTaskRemoved
---------------------------- PROCESS ENDED (28705) for package com.example.app ----------------------------

Again, onDestroy isn't called so the session isn't released and the notification player remains, but unlike in scenario 1 it doesn't work. Releasing the session before stopSelf doesn't result in onDestroy being called, but the notification does get removed and everything seems to be working properly as before.

[marcbaechinger]

I'm assuming it's because the session hasn't been released.

If this is the case, then there is a Media3 controller bound to the service that isn't yet unbound. Then stopSelf will not stop the service and hence onDestroy() isn't called.

Are you using a controller in your activivty as well? Where and when in your Activity do you release the controller? Because if the controller isn't released it is still bound to the service and the service won't stop.

[k-arabadzhiev]

Are you using a controller in your activivty as well?

Well in some ViewModels I have injected MusicServiceConnection which has MediaBrowser inside. That's how I'm interacting with the media3 player (i.e. adding MediaItems to the browser using setMediaItems, play/pause, collecting playback state). Releasing the controller is the same as here.
I hope that answers your question, because other than that I don't think I'm using a controller in my activity.