audioTrackGroupHandling
A policy that defines how the session exports alternate audio tracks.
Declaration
var audioTrackGroupHandling: AVAssetTrackGroupOutputHandling { get set }Discussion
By default, a session exports only the enabled audio tracks within an alternate track group from the source asset. You can specify that the session preserve all audio tracks within an alternate track group by setting this value to preserveAlternateTracks.
If no audio alternate track group is present, the value of this property has no effect. You can query the trackGroups property of AVAsset to determine whether it contains audio track groups.