Video trimmer: choose the part worth keeping
Use the video trimmer when the frame already looks right and the problem is timing. A pause before the subject moves, an accidental ending or a long lead-in can distract from a short product shot. Set the first useful moment as Start and the last useful moment as End. The preview uses that range; exporting creates a new WebM rather than changing your original file. If you need to remove something from the side of the image, use Crop video instead.