A value that indicates whether frame timing for the video composition is derived from the source's asset track.
- iOS 11.0+
- macOS 10.13+
- Mac Catalyst 13.0+Beta
- tvOS 11.0+
If an empty edit is encountered in the source asset’s track, the compositor composes frames as needed up to the frequency specified in
frame property. Otherwise the frame timing for the video composition is derived from the source asset's track with the corresponding ID.