Change a video's speed
Your files are processed on your device. We never upload them.
Video is read and written with Mediabunny, under the Mozilla Public License. Browsers without their own AAC encoder use FFmpeg's, under the GNU LGPL.
How to change a video's speed
- 01A ▸Choose your videos, or drop them on the page.
- 02A ▸Pick a speed, and whether to keep the sound.
- 03A ▸Select Change speed, then download each video.
Questions
Are my videos uploaded?
No. Your files are processed on your device. We never upload them.
Does the sound sound like chipmunks?
No. The sound is sped up or slowed down without changing its pitch, so voices stay recognisable. At the extremes (0.25× and 4×) speech gets a slight echo or choppiness; choose Leave it out for silent slow motion or time-lapse.
Is slow motion smooth?
Each frame is shown for longer; no frames are invented. A 30 frames-a-second video at 0.5× plays at 15 frames a second, which looks smooth enough for most clips. Videos recorded at 60 or 120 frames a second slow down best.
What happens to frames when I speed up?
Players show at most about 60 frames a second, so at high speeds some frames are left out to stay at 60.
Which speeds can I pick?
0.25×, 0.5×, 0.75×, 1.25×, 1.5×, 2×, 3×, and 4×.
How long does it take?
The picture and sound are re-encoded. On a computer the page shows an estimate under each video. Phone timings are still to be measured; for long or 4K clips a computer is faster.