Apple

On 18/01/2011, at 10:11 AM, Brian Willoughby wrote:

On Jan 17, 2011, at 15:55, Paul Fredlein wrote:
I'm recording to a single buffer as I need to only capture x seconds of audio. I've determined the buffer size by the number of seconds I need to record so when the buffer is full it stops recording. The maximum recording duration varies from 1 second to about 5 seconds maximum.

The file is called audioAppDelegate.m and in my callback I'm using 'self' as the 'inUserData'.

// set record callback
AudioQueueNewInput(&asbdRecord, recordCallback, self, NULL, NULL, 0, &queueRecord);

In my callback, I need to stop recording when the single buffer is full.

[(audioAppDelegate*)inUserData performSelectorOnMainThread:@selector(stopRecording:) withObject:nil waitUntilDone:NO];

This works but there must be a better way. Any help appreciated, thanks.
Why not just create a global variable - or, better yet, pass in the address of an instance variable as your inUserData - and set this variable when your recording data has been completely captured. In your App delegate, you can set up a timer to periodically poll this BOOL, and then call the -stopRecording: method when the flag changes. You don't need to set the timer to repeat very fast - in fact, you don't even need a repeating timer. If you do end up looping on the flag, make sure you call sleep() or the equivalent so that you don't end up with a busy wait and spinning cursor.

It's generally best to create standard C mechanisms for communication between the CoreAudio callbacks and the non-time-critical parts of your application.

Brian Willoughby
Sound Consulting

References:
	>OSX callback, is this OK? (From: Paul Fredlein <email@hidden>)
	>Re: OSX callback, is this OK? (From: Brian Willoughby <email@hidden>)