View Full Version : how to combine audio tracks

Jan 31, 2006, 03:07 AM
hi guys,

I m using core audio API's to play multiple files at single time. I m successful in that. Now my aim is combine these multiple tracks & save it(combined single file) to a disk.

Is this possible by using coreaudio api's?
Please guide me.

Jan 31, 2006, 04:39 AM
I've never used the audio APIs but I'd have thought the QuickTime APIs could do this if CoreAudio can't...

Jan 31, 2006, 06:34 AM
Is combining audio tracks possible using Core Audio API?

Jan 31, 2006, 07:30 AM
Can't this be accomplished in GarageBand?

Feb 1, 2006, 03:16 AM
Hey guys,

Actually I m writing cocoa program in which I m using core audio API's.
So I have got this question that how to combine audio tracks.

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Feb 1, 2006, 03:37 AM
You probably want to combine the tracks using a mixer AU (like MatrixMixer or StereoMixer). Then send the output of that to a FileWriter unit (I think you'd want to set the offline rendering property here). If you need to hear it at the same time, things get trickier I think, because you can only have one output per graph. In that case you need to tap off another unit's buffers from the render callback, copying the data out of the callback function on each pass and manually writing the data to a file in a separate thread. I believe there's an example that does this somewhere (maybe the AULab app included with the Developer install).