On OS X API, you use an AVAssetWriter object to write media data to a new file of a specified audiovisual container type, such as a QuickTime movie file or an MPEG-4 file, with support for automatic interleaving of media data for multiple concurrent tracks
IPhone - To perform a real-time or offline capture, you instantiate an AVCaptureSession object and add appropriate inputs (such as AVCaptureDeviceInput), and outputs (such as AVCaptureMovieFileOutput).
|Far more rudimentary||
"Avcapturesession is far more rudimentary compared to avaudiorecorder - it does not provide any recording facilities by itself for example and so if you wanted to also record the audio you would need to use an avassetwriter to save the samples"
from question "Audio waveform visualization in swift"