Video Trimmer & Cutter
Trim or cut a clip from a video locally in your browser, fast and without re-encoding.
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A video trimmer lets you keep just the part of a clip you want, cutting away the dead air at the start, the fumble at the end, or pulling a short highlight out of a longer recording. You give it a start time and an optional end time, and it writes out only that section. Trimming is one of the most common video edits, and it does not require a full editor: a single precise cut is often all you need before sharing or uploading.
Frequently asked questions
Is my video uploaded to a server?
Does trimming reduce quality?
Why is the cut slightly off from the time I entered?
What time format should I use?
What formats can I trim?
Is there a file size limit?
Can I cut out a section from the middle?
Does it work offline?
About Video Trimmer & Cutter
This trimmer works entirely inside your browser using a WebAssembly build of FFmpeg, so your video never leaves your device. It also performs the cut by stream copying, copying the existing audio and video data straight into a new file instead of re-encoding it. That makes trimming almost instant even on large files, and it means there is zero quality loss: the kept section is bit-for-bit identical to the original.
Because stream copy can only cut cleanly at keyframes (the periodic complete frames in a compressed video), the actual cut may land a fraction of a second from the exact time you typed, snapping to the nearest keyframe before your start point. For most clips this is imperceptible. If you need frame-exact cuts you would have to re-encode, which is slower and slightly lossy; for the vast majority of trimming tasks, fast keyframe-accurate cutting is exactly what you want.
Times are entered as HH:MM:SS (for example 00:01:30 for ninety seconds in). Leave the end blank to keep everything from the start time to the end of the video. The output keeps the original container and codecs, so an MP4 stays an MP4 and plays anywhere the original did.
Keyframes: why video scrubbing snaps where it does
Compressed video is not a simple sequence of complete pictures. To save space, codecs store occasional full frames, called keyframes or I-frames, and describe the frames in between as changes relative to their neighbours (P- and B-frames). A P-frame might say move this block of pixels left and brighten it slightly rather than redrawing the whole image. This is what makes video files small, but it also means most frames cannot be decoded on their own, they depend on the keyframe before them.
That dependency is why fast, lossless trimming can only start at a keyframe: to begin playback mid-stream you need a self-contained frame to start from. Cutting at an arbitrary frame would require decoding back to the previous keyframe and re-encoding, which is slower and loses a little quality. Stream-copy trimming sidesteps that by snapping to the nearest keyframe and copying the data verbatim.
The spacing of keyframes (the GOP, or group of pictures) is a choice made when the video is encoded. Streaming formats use frequent keyframes so players can seek and adapt quality smoothly; archival encodes use sparse keyframes for maximum compression. It is the same reason a progress bar sometimes jumps to a slightly different spot than where you clicked: the player is seeking to the nearest keyframe.