Recipe: Recording Audio with Audio Queues

In addition to the AVAudioPlayer class, Audio Queues can handle recording and playing tasks in your applications. Audio Queues were needed for recording before the AVAudioRecorder class debuted. Using queues directly helps demonstrate what’s going on under the hood of the AVAudioRecorder class.

Recipe 20-6 records audio at the Audio Queue level, providing a taste of the C-style functions and callbacks used. This code is heavily based on Apple sample code and specifically showcases functionality that is hidden behind the AVAudioRecorder wrapper.

The settings used in Recipe 20-6’s setupAudioFormat: method have been tested and work reliably on the iOS family of devices. It’s easy, however, to mess up these parameters when trying to customize your audio quality. If you don’t have the parameters set up just right, the queue may fail with little feedback. Google provides copious settings examples.