How to monitor audio on iPhone headphones from AVCaptureSession?

Question

I want to be able to monitor audio on headphones before and during the capture of video.

I have an AVCaptureSession set up to capture video and audio.

My idea is to hook and AVCaptureAudioDataOutput instance up to the AVCaptureSession for this and process the CMSampleBufferRefs with a class implementing the AVCaptureAudioDataOutputSampleBufferDelegate protocol.

But I am not sure how to route the audio to the headphones from there.

What would be the most straighforward way to do this (highest level frameworks, general approach)?

Answer 1

I ended up implementing this Audio Unit. The remote i/o audio unit to be precise. Apple's aurioTouch sample code provides a clear example of how to do this.