AudioQueue callback get empty buffer on iOS 7 only

Question

I got a strange issue. My code works great on both iOS 5&6 but when running on iOS 7 I get empty buffers on the AudioQueue callback.

Possible relevant code:

Answer 1

@Idan your answer is correct and working but it only shows warning if app minimun deployment target is iOS 7. For iOS 7 we can do something like this:

NSError *audioSessionError;
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&audioSessionError];

if(audioSessionError)
{
    NSLog(@"AVAudioSession error setting category:%@",audioSessionError);
}
else
{
    [audioSession setActive:YES error:&audioSessionError];
    if(audioSessionError)
        NSLog(@"AVAudioSession error activating: %@",audioSessionError);
}

Answer 2

I found the issue! seems like on iOS 7 there is a need to set this also (I assume this is only practically therefore it's hard to find, isn't written anywhere). Just add this code before calling any AudioQueue function:

AudioSessionInitialize(NULL,
                       NULL,
                       nil,
                       ( void *)(self)
                       );

UInt32 sessionCategory = kAudioSessionCategory_PlayAndRecord;
AudioSessionSetProperty(kAudioSessionProperty_AudioCategory,
                        sizeof(sessionCategory),
                        &sessionCategory
                        );

AudioSessionSetActive(true);

Hope that would help others.

Another resource that can help can be found here.