Speed Up or Slow Down a Video
Speed a clip up or slow it down, picture and sound together.
Play a video at half speed for slow motion, or 1.5x, 2x, 4x or 8x for a time-lapse. The sound follows the picture. Free, no watermark, nothing uploaded.
What this tool is for
A lecture you want to get through, a demonstration that moves too fast to follow, or an hour of footage that should be a timelapse.
Choosing a speed
Half speed gives smooth slow motion from footage shot at 60 frames a second, and a stepped look from ordinary 30. 1.5x and 2x suit tutorials and screen recordings. 4x and 8x make a time-lapse.
What happens to the sound
The sound is sped up or slowed down with the picture so they stay in step.
How to use it
- Add your files. Drop them on the page or choose them. They stay on your device.
- Set the output format and quality. The defaults suit most files.
- Press convert and save the results, individually or as one ZIP.
Questions
Does the audio go squeaky?
No. The pitch is preserved: the sound is time-stretched rather than simply played faster, which is what makes speech at double speed still sound like the person talking. Very large changes are reached in stages for the same reason, because one extreme stretch sounds worse than two moderate ones.
Does speeding up drop frames?
The timestamps are rewritten rather than frames thrown away, so at double speed every frame is still there and the file simply plays through them twice as fast. At very high speeds the result has a high frame rate, which some players handle better than others.
Does slowing down make it smoother?
It makes it longer, not smoother. Half speed shows each original frame for twice as long, so motion looks stepped. Genuinely smooth slow motion needs footage shot at a high frame rate in the first place; nothing can invent frames that were never recorded.
Can I change the speed of audio on its own?
Yes. Audio files are accepted and get the same pitch-preserving treatment, which is how most podcast apps do it.