Write the output of a Remote IO Audio Unit to a file offline

Question

I have a program that generates sound using an AUSampler connected to a Remote IO Audio Unit. The AUSampler is controlled by pre-recorded events that are triggered in a timed loop. I want to write the resulting sound to a file.

There are some other questions on writing to a file in the render callback of the IO unit:

• Recording to AAC from RemoteIO: data is getting written but file unplayable
• How to write output of AUGraph to a file?
• Recording from RemoteIO: resulting .caf is pitch shifted slower + distorted
• Write Audio To Disk From IO Unit

But these all deal with writing the data in real time. Is there a way to offline render the file in less time it takes than to play it?

Answer 1

If you are rendering a pre-recorded sequence, then why not just write raw PCM data to disk? The ExtAudioFileWriteAsync function should work in this case.