Trimming is the process of adding or removing frames from the beginning or end of a clip in order to change its duration. Trimmed frames are not physically removed from the clip, but rather are stored in areas referred to as the head and the tail of the clip, where they can be reapplied to the clip by further trimming at any time. Certain operations, however, such as consolidating or committing a clip, permanently remove head and tail frames from the framestore.
You can also slip and slide clips, and slide transitions. When you slip or slide a clip or slide a transition, you only modify the head or tail frames or the in and out points to change the frames that appear in the final edit. You do not change the duration.
You can trim clips in the timeline in the Player and in the timeline in Batch.