Finding the number of Channels from an AVAsset

Question

I am loading Audio assets via AVAssets. I want to figure out how many channels (mono or stereo basically) are in the asset. What is the best way to do this?

Answer 1

This appears to be what I am looking for.

AVAssetTrack* songTrack = [mAssetToLoad.tracks objectAtIndex:0];
NSArray* formatDesc = songTrack.formatDescriptions;
for(unsigned int i = 0; i < [formatDesc count]; ++i) {
    CMAudioFormatDescriptionRef item = (CMAudioFormatDescriptionRef)[formatDesc objectAtIndex:i];
    const AudioStreamBasicDescription* bobTheDesc = CMAudioFormatDescriptionGetStreamBasicDescription (item);
    if(bobTheDesc && bobTheDesc->mChannelsPerFrame == 1) {
        mIsMono = true;
    }
}