kAudioSessionSetActiveFlag_NotifyOthersOnDeactivation not work with bluetooth headset
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I have an app that will play some audio voice. I want other apps would be ducked when my app is playback. The app works fine with iPhone speaker, that is, when my app play voice, iPod will play music with lower volume and it will back to the original volume when my app playback finish.

But when I connect Bluetooth to my iPhone, the iPod will not back to its original volume until it change to another song.

Do I need to do other setting if I want it works with bluetooth?

Here are some settings I used:

    OSStatus error = AudioSessionSetProperty (kAudioSessionProperty_OverrideCategoryMixWithOthers,
                                                  sizeof (allowMixing), &allowMixing);
    
    error = AudioSessionSetProperty(kAudioSessionProperty_OtherMixableAudioShouldDuck,
                                            sizeof(allowDucking), &allowDucking);
    
    AudioSessionSetActive(YES);
    
    // Code about playback...
    // ...
    // .. 
    
    // End playback
    AudioSessionSetActiveWithFlags(false,kAudioSessionSetActiveFlag_NotifyOthersOnDeactivation);

Thanks!!