How to trim a video without losing quality
Updated: November 6, 2026
Cutting the first seconds where you adjust the camera, the ending where you say goodbye or pulling out a specific clip is the most common edit there is. What many people don’t know is that you can do it without compressing the video again, so it loses no quality and takes seconds.
Trimming without re-encoding: the idea
A video is stored in chunks that start at keyframes, usually one every few seconds. If you cut right at those points, the program just copies the chunks you want: no loss and almost instant.
The trade-off is that the cut may shift a second or two to the nearest keyframe. If you need a frame-exact cut, that video has to be re-encoded.
On a computer: LosslessCut (free)
- 1Download LosslessCut, free and open source, for Windows, Mac or Linux.
- 2Open the video and mark the start and end of the part you want to keep.
- 3Click “Export”: it saves the clip without re-encoding, in seconds.
With FFmpeg (one line)
If you already use FFmpeg, this command keeps 1:00 to 2:30 without re-encoding:
ffmpeg -ss 00:01:00 -to 00:02:30 -i input.mp4 -c copy output.mp4
# Frame-exact cut (re-encodes the video at good quality):
ffmpeg -ss 00:01:00 -to 00:02:30 -i input.mp4 -c:v libx264 -crf 18 -preset medium -c:a aac -b:a 160k output.mp4On your phone
- iPhone: open the video in Photos → Edit and drag the ends of the timeline.
- Android: in Google Photos → Edit → Trim, drag the ends and save a copy.
- Built-in apps may re-compress when saving: fine for a quick trim, but keep the original.
Do you need to cut the intro?
If you just don’t want your audience to sit through the intro, you don’t need to edit the file: on Dembed you can mark the intro section and the player shows a “Skip intro” button (or skips it automatically). That way you keep the full video.
Frequently asked questions
Because without re-encoding the cut snaps to the nearest keyframe. For an exact cut, re-encode.