QuickTime 4 Reference

Specifying an Offset for a Tween Operation

You can start a tween operation after a tween media sample begins by including an optional kTweenStartOffset atom in the kTweenEntry atom for the tween. This atom specifies a time interval, beginning at the start of the tween media sample, after which the tween operation begins. If this atom is not included, the tween operation begins at the start of the tween media sample.