Apple

I think in favour of a tractable implementation, I might go with #1; I dread the idea of trying to manually mix arbitrary audio stream formats. Feels a little bit wacky, but I guess that's Core Audio.

On 14 Feb 2012, at 19:25, Michael Tyson wrote:

1. MultiChannelMixers + AudioConverters - Use an audio converter to convert from whatever the MultiChannelMixer's output is, into the main format, then extract/process the audio. If altered, then the audio needs to be converted back to the same format and written to the buffer provided from the mixer's render callback. Or, I suppose I can replace the AUGraph connection with an input callback for the next mixer in the chain, which calls AudioUnitRender upon the MultiChannelMixer, and just performs one conversion, from the mixer's output.

2. Perform all mixing manually from an input callback, using the Accelerate framework for the heavy lifting, and keep everything in the same audio format.

Is there one option that appears clearly superior? I'm always in favour of using what's already there, and not re-inventing the wheel, but given the limited output formats that MultiChannelMixer can provide, am I better off throwing it all away and rolling my own? Or is the audio converter likely to be light enough to make it worth sticking to what's there?