AVCaptureAudioDataOutput To AudioUnit iOS

at Apple iOS developer Library

iOS code that demonstrates AVCaptureSession, AUGraph. Also, how to write audio data to a file. Basically the app records from the built-in mic and process with an AU delay effect

https://developer.apple.com/library/ios/#samplecode/AVCaptureToAudioUnit/Introduction/Intro.html#//apple_ref/doc/uid/DTS40012880