Quick answer
Pick Playback speed, then export. Options are 0.5x (slow), 0.75x, 1.25x, 1.5x, and 2x (fast). Audio is retimed with the picture. Processing uses FFmpeg in the tab, so the clip is not uploaded.
Speeds you can pick
The control is a single Playback speed menu. 0.5x is half speed (slow motion feel). 2x is double speed. In-between steps are 0.75x, 1.25x, and 1.5x. There is no custom decimal beyond those presets.
How to change speed here
- Drop an MP4, MOV, WebM, or similar clip.
- Choose 0.5x, 0.75x, 1.25x, 1.5x, or 2x.
- Run Change speed. Wait for on-device encode.
- Preview, then Download. Use New to start another file.
Audio and length
Sound is stretched or compressed with the video so speech still lines up. 2x shortens duration; 0.5x lengthens it. Very large files can take minutes because encode happens on your CPU in the browser.
Privacy
FFmpeg WebAssembly runs locally. The tool does not call an AI or upload API for speed changes.
Frequently Asked Questions
Yes. Speed and audio are adjusted together so they stay in sync at 0.5x through 2x.
Not in this menu. The presets stop at 0.5x on the slow side and 2x on the fast side.
No. Encoding stays in this browser tab.
No. Web tools do not add a watermark on this export.