Trimming and cropping are two different video editing techniques. To trim a video is to change the playback time by erasing unwanted scenes. This can be at the start and endpoints or anywhere in the video timeline. On the other hand, cropping is to change the video frame so that some objects are not visible. In other words, cropping has nothing to do with changing the playback duration. You'll often find video creators cropping a video to zoom it or remove unwanted objects like logos and watermarks. Learn best MP4 Video Trimmer App 2022