Trim Video
Cut a clip precisely. Keyframe cuts finish in milliseconds without re-encoding.
How to trim video
- Drop a video onto the timeline. The scrubber loads from the local file — nothing is uploaded.
- Drag the in-point and out-point handles to mark your clip, or type timestamps directly.
- Click Trim. If the cut lands on a keyframe boundary, stream copy finishes in under a second. Otherwise a re-encode begins — you can watch the progress.
About this tool
Most "video trimmer" tools online either re-encode your whole video through their servers — which is slow, lossy, and means your footage travels to a stranger's infrastructure — or they trim imprecisely and produce corrupted start frames. Stream copy does neither. When the WebCodecs API locates the keyframe at or before your cut point and copies from there, the resulting file is byte-for-byte identical to the original in that region. On a long recording you are genuinely done in under a second.
The catch is honest and clearly stated: keyframe intervals in H.264 files shot on a phone are typically every half-second to two seconds, so stream copy might start your clip up to two seconds early. For most editing that is acceptable — trim in a little, get the exact cut. When it is not, disabling stream copy tells the engine to decode and re-encode from the precise frame you selected. That is slower but frame-accurate.
WebCodecs is supported in Chrome and Edge from version 94, Firefox from 130, and Safari from version 26. Where it is available the encode uses hardware acceleration and the performance is close to native desktop tools. Where it is not, ffmpeg.wasm is the fallback — capable, but noticeably slower. A status badge in the UI shows which path is running so you know what to expect.