AudioQueueStart fails when iphone app running in background iOS4.0

I'm having difficulties starting the AudioQueue when my app is in the background with iOS4.0 The code works fine when the ap开发者_C百科p is active, but fails with -12985 code when running in the background.

        err = AudioQueueStart( queueObject, NULL );


        if( err )
        {
            NSLog(@"AudioQueueStart failed with %d", err);
                = NO;
AudioQueueStop(queueObject, YES);
            return;
        }

For the code above, err is set to -12985

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Making sure that my AudioSession was active fixed the problem: Previously in code I had set the session to inactive between song changes before starting a new song:

AudioSessionSetActive(false);

Once I removed this AudioQueueStart works just fine from the background.

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From Apple Developer Forums:

The solution is actually simple once you know it, and I really wonder why so many question like your spread in many forums don't get answred

...

You to this ensuring your view becomes First Controller and then calling

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

n viewDidLoad. Once you do this, your Player will no longer return NO!!

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I've since learned that re-using an audioqueue from the background works just fine. You just can't start new.