Speed up or slow down a video - locally in the browser, no upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
A timelapse out of a long recording, a slow-motion effect for a short clip, or just a video that was recorded too slow or too fast - this tool adjusts playback speed without changing picture quality.
Important and honest: the audio track is removed, not sped up or slowed down along with the video. A naive time-shift of the audio without pitch correction would need real audio time-stretching, which this tool deliberately does not offer - an honest video-only result beats a garbled one.
Everything runs locally in the browser with mediabunny (MPL-2.0, self-hosted, no third-party CDN) on the browser's native WebCodecs API. Your video is not uploaded.
| Input formats | MP4, M4V, MOV, MKV, WEBM |
|---|---|
| Output format | MP4 |
| Batch processing | No |
| Processing | Locally in your browser (WebCodecs) |
| File upload | None |
Limitations: Always removes the audio track (no audio time-stretching). Factor between 0.25x and 4x. Full re-encode, so it takes longer than a pure stream copy. One file per run, ~600 MB limit (the browser tab's memory limit: without streaming support the file must fit in whole, with streaming it rises to about 1 GB).
No. The whole adjustment happens locally in your browser.
Correctly time-shifting audio needs real time-stretching, which this tool deliberately does not offer - honestly silent beats garbled.
No, only the preset steps from 0.25x to 4x.
A small, usual re-encoding loss is unavoidable because the video is recomposed.
No, only playback speed - width and height stay unchanged.
Video watermark · Rotate video · Compress video · Video thumbnail · Merge videos · Replace video audio