AVAudioEngine input only: how to schedule

Dear all,


I'm currently working on an audio app with input only, for sound analysis. As usual, I'm working with AVAudioEngine with custom AUAudioUnit to embed my own real-time audio processing code.


My question is the following: how can I properly schedule the calls of the input node's render callback?


I'm used to work with both input and output, and in that case, the system callback on the output node triggers everything up to the input node's render callback. But without an output, I have no idea how to schedule my calls to the input node's render callback.


For now, the solution I found is to create an output bus on my analysis node, and plug it to the output node. That way, I can rely on the output node calls for the scheduling while allways sending empty buffer (with the OutputIsSilence flag).


Any better idea?


Thank you all 🙂


Tom