A fit-to-fill edit is a convenient means for quickly creating a timewarp that exactly fits a pre-determined space in the timeline. You mark in and out points in both the source clip and the record clip, and edit the clip into the timeline. The timewarp is calculated automatically based on the difference between the source and record durations.
If the source clip includes edits such as cuts or transitions, you must choose how you want them treated in the timewarp. To preserve the edits so you can continue to work with them, you create a container for the clip. The timewarp will be applied to the container, and the edits will be preserved. If you choose not to create a container, the resulting element in the timeline is a timewarped, hard-committed version of the source clip. See . In either case, the heads and tails of the source clip are retained.