Notes

Duration can be used to scale the entire movie.

A change in duration will result in a pitch change in the movie as well. For example, making the movie longer causes the pitch to be lowered.

StartPosition is the beginning of the segment to be scaled.

OldDuration is the current duration of the segment and NewDuration is the duration the segment should be scaled to.

If the operation is time-consuming, QuickTime will display a modal dialog with a progress indicator if ShowProgress is True.