Trim and cut a video
Cut a clip out of any video with a dual-handle slider and a live preview. Lossless stream copy or a frame-exact re-encode, all in-browser.
- Runs in your browser
- Files are never uploaded
- Free, no account
First use downloads the 10 MB video engine from this site. After that it is cached and works offline. It is WebAssembly served from onthisdevice.com — no third-party CDN — and your file is still processed entirely on your own device.
How to trim a video
- Drop the video in — it appears in a normal player straight away, with no upload wait.
- Drag the start and end handles, or scrub the player to the right moment and press Set here.
- For frame-level precision, type a timecode such as
1:23.50directly into the start or end field. - Leave the mode on Lossless unless you need the cut to land on an exact frame.
- Press Trim video, preview the clip and download it.
Lossless copy versus frame-exact re-encode
| Lossless (stream copy) | Frame-exact (re-encode) | |
|---|---|---|
| Quality | Identical to the source, bit for bit | One extra lossy generation |
| Speed | Seconds, regardless of length | Roughly real time, sometimes slower |
| Cut accuracy | Snaps back to the nearest keyframe | Exactly the frame you chose |
| Output format | Same container as the input | MP4 (H.264 + AAC) |
Why a lossless cut can start early
Modern codecs only store a handful of complete pictures — keyframes, or I-frames. Every other frame is described as a difference from its neighbours, so it cannot be decoded on its own. When FFmpeg copies a stream rather than re-encoding it, the clip has to begin at a keyframe, otherwise the first second would be a smear of half-decoded blocks.
Cameras and screen recorders typically place a keyframe every 1-10 seconds, so a lossless cut can begin up to that far before the point you picked. If the first frame matters — a music cue, a punchline, a slide change — switch to frame-exact mode and accept the re-encode.
Keyboard and accessibility notes
- Tab to either slider handle and use the left/right arrow keys to nudge it; Home and End jump to the ends.
- The start and end fields accept
ss,m:ss,m:ss.ssandh:mm:ss.ss. - Progress, errors and the finished-clip announcement are all exposed as polite live regions for screen readers.
Typical uses
- Cutting dead air from the start and end of a screen recording before sharing it.
- Isolating a highlight from a long match or stream, without waiting for a 2 GB upload.
- Meeting evidence — clip the 30 seconds that matter out of an hour-long recording that must not leave your laptop.
- Feeding an editor — a lossless cut keeps the original codec, so your NLE re-imports it without another generation of loss.
Questions
What is the difference between lossless and frame-exact mode?
Lossless mode copies the encoded video stream straight through, so quality is untouched and the export takes seconds — but the cut has to start on a keyframe, which can be a second or two before the point you chose. Frame-exact mode re-encodes, landing precisely on your frame at the cost of time and a little quality.
Why does my lossless clip start earlier than I asked?
Because a video frame in the middle of a group of pictures cannot be decoded on its own. Stream copy therefore begins at the nearest preceding keyframe. Switch to frame-exact mode when the exact first frame matters.
How do I set the handles precisely?
Play the video, pause where you want the cut and press "Set here", or type a timecode such as 1:23.50 into the start or end box. The slider handles also respond to the arrow keys once focused.
Can I keep the original format?
Lossless mode always writes back to the same container — MP4 stays MP4, MKV stays MKV. Frame-exact mode outputs MP4 because it re-encodes with H.264.