The player should properly expose audio focus state

[jakoss]

Issue description

I'm trying to get AudioFocus behavior: duck (lower volume) on notifications and pause on incoming call (and play after call end). When i look at the code https://github.com/google/ExoPlayer/blob/release-v2/library/core/src/main/java/com/google/android/exoplayer2/audio/AudioFocusManager.java#L419 default ExoPlayer implementation should be working like this (or maybe i don't understand it well). But unfortunetely - on incoming call volume is down to 0, but playback doesn't stop.

Interestingly enough. CONTENT_TYPE_SPEECH is not working either. Playback isn't stopped on both - notifications and incoming call.

Reproduction steps

I set audio attributes like this

setAudioAttributes(AudioAttributes.Builder()
    .setContentType(C.CONTENT_TYPE_MUSIC)
    .setUsage(C.USAGE_MEDIA)
    .build(), true)

In logs i can see that AUDIOFOCUS_LOSS_TRANSIENT was dispatched. It seems like PLAYER_COMMAND_WAIT_FOR_CALLBACK wasn't handled properly.

D/AudioManager: dispatching onAudioFocusChange(-2) to android.media.AudioManager@1420c8com.google.android.exoplayer2.audio.AudioFocusManager$AudioFocusListener@d3f1561
D/AudioManager: dispatching onAudioFocusChange(1) to android.media.AudioManager@1420c8com.google.android.exoplayer2.audio.AudioFocusManager$AudioFocusListener@d3f1561

EDIT: when i digged deeper i found that on SimpleExoPlayer ComponentListener to PlayerCommand is ignoring PLAYER_COMMAND_WAIT_FOR_CALLBACK completely

private void updatePlayWhenReady(
      boolean playWhenReady, @AudioFocusManager.PlayerCommand int playerCommand) {
    player.setPlayWhenReady(
        playWhenReady && playerCommand != AudioFocusManager.PLAYER_COMMAND_DO_NOT_PLAY,
        playerCommand != AudioFocusManager.PLAYER_COMMAND_PLAY_WHEN_READY);
  }

Version of ExoPlayer being used

2.10.3

Device(s) and version(s) of Android being used

Samsung Galaxy S7 Edge, Android 8.0; Huawei Mate 20 lite, Android 8.1; Samsung Galaxy A7 (2018), Android 9

Also emulators of Pixel 2 devices using Android 8, 9 and Q (9+)

[google-oss-bot]

This issue does not seem to follow the issue template. Make sure you provide all the required information.

[andrewlewis]

I think the updatePlayWhenReady code does identify PLAYER_COMMAND_WAIT_FOR_CALLBACK (it's different to the other two possible constants). Could you add some logging in that method to check what parameters are passed to setPlayWhenReady when audio focus is lost transiently and gained again?

[andrewlewis]

Testing on API 26 emulator I also can't reproduce the behavior you're seeing (after enabling audio focus handling as per your code snippet above, the player pauses when I simulate an incoming call and resumes afterwards).

[jakoss]

Hi. Thanks for taking interest in this issue. Maybe the issue is bound to some other functionality (MediaSessionConnector or any other additional ExoPlayer classes i'm using). I managed to create simple reproduce project, that have this behavior (tested on API 28 Emulator and Nokia 8 device). In this project i'm using only ExoPlayer classes to play one online hls track. On call - playback doesn't get paused (you can see that on state textview and on notification). Let me know if i can assist you more
AudioFocus.zip

[ojw28]

I gave your demo a try and playback is definitely pausing and resuming correctly.

I think what you're confused by is that getPlayWhenReady continues to report true, even though playback is not continuing internally. This is by design for transient loss of focus, when the player is expected to be able to resume once focus is returned.

You may just want to track #5087. Alternatively, is this causing any concrete issues for you?