I am adding a voiceover track to an existing video, which may include audio tracks. I'm using AVAssetExportSession to render the video to a .mov.
I'd like to keep track of which audio track is the voiceover, so if the user later wants to edit the voiceover, I know which track to update. I thought I would use a unique trackID.
So I call:
let compositionAudioTrack = composition.addMutableTrack(withMediaType: .audio, preferredTrackID: myAudioTrackID)!
where myAudioTrackID is a random Int32 I generated. I have confirmed that the trackID for the returned compositionAudioTrack is indeed = myAudioTrackID.
But when I render the video usign AVAssetExportSession, the trackID is reassigned to some other number.
How can I keep track of which audio track is mine?
