I was wondering if anyone know how to get preferred channel layout from CoreAudio. I try to use kAudioDevicePropertyPreferredChannelLayout to get the channel label. However, it always shows kAudioChannelLabel_Unknown value. Is there something driver issue? or it's necessary to set some properties before asking kAudioDevicePropertyPreferredChannelLayout.
my code is here: https://gist.github.com/ChunMinChang/ea74c8228745449873716e1d98ba956e/e61fedea3e08bcff64ef3db05931a1c757768d70