Trim a clip when you want to alter the In and Out points for a specified length of time without affecting the clip. When you Trim a clip, you select only a segment of the original animation, audio or video, which you can then loop or scale.
Looping clip A. First loop B. Mark In C. Mark Out
To trim an animation, video, or audio clip:
Move the indicator to where you want to trim the start of the clip.
The entire original clip is shown with the marked segment of the clip added to the end. The marked segment is shown looped until the end time of the original take.
Move the indicator to where you want to trim the start of the clip.