View in HD at . If you want to trim some video from the beginning or end of a movie file, you don't need to use a video editing app. You can do it right in QuickTime Player. Trimming is lossless and can be done with precision. You can also cut sections out of the middle of your video and export a new copy. You can trim in the Photos app as well, though the original full-length video is always available if you wish to revert.