I am having a similar problem. I am trying to record AAC audio using remoteio, for pretty much all the same reasons you described here:
http://lists.apple.com/archives/coreaudio-api/2012/Oct/msg00135.html
My current problem isn't even with interuptions. If I dispose of my audio unit and set my audio session to inactive on being moved to the background, I still have the media server get killed when I try to reactivate my session when the app reloads.
My basic flow that is dying is this:
- set up an active audio session for recording
- setup an audio unit & and file in preparation for the user pressing the 'record' button
- user backgrounds the app, in order to tear down everything I dispose of my audio unit and deactivate my session, but I don't clean up my extaudiofile at this point
- I open voice memos, and then immediately close it
- reopen my app and hit record.
- when I try and set the session to active, mediaserverd dies. Switching to the software codec didn't fix it!
If you have learned any more about this craziness I would love to hear what you figured out.
Thanks.