You can trim the frames from the beginning and end of a video that you just recorded, or from
any other video in your Camera Roll album. You can replace the original video, or save the
trimmed version as a new video clip.
Trim a video: While viewing a video, tap the screen to display the controls. Drag either end of the
frame viewer at the top of the video, then tap Trim.
If you choose Trim Original, the trimmed frames are permanently deleted from the
original video. If you choose “Save as New Clip,” a new trimmed video clip is saved in your Camera
Roll album and the original video is unaffected.