title: AVAudioRecorder in iOS 8 does not handle kAudioFormatMPEG4AAC
body: <p>My code worked fine until iOS 8 <code>kAudioFormatMPEG4AAC</code> but now it creates an empty file. No errors are reported. When I changed it to <code>kAudioFormatLinearPCM</code> it works. This is my code:</p>
  
  <pre><code>recordSettings = [NSDictionary dictionaryWithObjectsAndKeys:
      [NSNumber numberWithInt:AVAudioQualityMin], AVEncoderAudioQualityKey,
      [NSNumber numberWithInt: kAudioFormatLinearPCM], AVFormatIDKey,
      [NSNumber numberWithInt:16], AVEncoderBitRateKey,
      [NSNumber numberWithInt: 1], AVNumberOfChannelsKey,
      [NSNumber numberWithFloat:32000.0], AVSampleRateKey,
      nil];
  </code></pre>