Apple

Sorry if this has been asked before. I tried googling but did not find much.

I have a farily simple Audio Graph with a kAudioUnitSubType_AudioFilePlayer upstream and kAudioUnitSubType_RemoteIO down stream. In between their maybe an arbitrary number of Audio Units, and maybe a couple of buffers. How can I know when the last sample as been rendered by kAudioUnitSubType_RemoteIO ? I want to update my UI when this event occurs.

I know ScheduledAudioFileRegion.mCompletionProcUserData can be use to register a call back function to receive callbacks when the file player AU finishes how ever how would I know when all the samples have made their way through the entire graph?

I found AUGraphAddRenderNotify From the documentation

"Adds a callback that the graph will call every time the graph renders. The callback will be called once before the graph’s render operation,

and once after the render operation is complete."

I wrote a little test program setting ScheduledAudioFileRegion.mCompletionProcUserData and using AUGraphAddRenderNotify().They share a boolean. The boolean is set in ScheduledAudioFileRegion.mCompletionProcUserData, and check in the AUGraphAddRenderNotify callback.

AudioFileRegionCompletionProc() {

Done = YES;

}

AUGraphAddRenderNotify() {

If (done) {

AUGraphStop(inUserData->audioGraph);

Update UI

}

When I ran my test program, I found AUGraphAddRenderNotify 2 times after done was set to true; Causing stop to be cause twice

AUGraphAddRenderNotify filePlayerFished = 0 AUGraphAddRenderNotifyCount = 1407

Audio Unit File Player callback : filePlayerFished = 1 AUGraphAddRenderNotifyCount = 1408

AUGraphAddRenderNotify filePlayerFished = 1 AUGraphAddRenderNotifyCount = 1409

!!!!!!!!!! AUGraphAddRenderNotify stop !!!!!!!!!!!!

AUGraphAddRenderNotify filePlayerFished = 1 AUGraphAddRenderNotifyCount = 1410

!!!!!!!!!! AUGraphAddRenderNotify stop !!!!!!!!!!!!

Where all the samples rendered? Also AUGraphAddRenderNotify() gets called twice on each render cycle. These seems like a lot of overhead.

Is there a better way to implement this?

Thanks

Andy