Channel routing on MacOS

[alexandrebeaudet]

Hello,

I'd like to make my app respect the Midi Configuration audio routing on MacOS ; has anyone managed to it yet with miniaudio ?

It seems the channel mapping system in miniaudio is used for left/right/back/front routing, but the issue is with an USB mixer/interface that has multiple stereo pairs of outputs.

Some audio interface use a driver and an app to make the routing, so it's not an issue working with them (the routing is completely handled on the interface side), but with the Mackie ProFX mixer, the routing is done via the Midi Configuration tool.

Other apps respect the routing and I suspect they fetch some CoreAudio parameter that defines the system routing. Does anyone know which parameter to use ? Didn't find it yet (still looking for it)

Thanks :)
Alexandre

Edit: also shouldn't the miniaudio playback channel mapping respect the CoreAudio driver configuration ? Like, the CHANNEL_FRONT_LEFT/RIGHT values should have the same position as in Midi Configuration, no ?

[alexandrebeaudet]

Ok I think I found what I was looking for :)))
In CoreAudio (AudioHardwareDeprecated.h 🫠), there's a kAudioDevicePropertyPreferredChannelsForStereo property. It points to the correct channels that have been set up in Midi Configuration.

So there's that ; just got to map my app's channels to the indices of "preferred stereo channels" :)