Video Speed Changer
Speed up or slow down video
Speed up or slow down video Runs locally in your browser
About the
The Video Speed Changer speeds up or slows down video from 0.25x to 4x, running locally in your browser with ffmpeg. Video frames are retimed with setpts while audio is stretched with a chained atempo filter, so pitch stays natural instead of turning into a chipmunk.
Speed presets cover the everyday cases: 2x and 4x for condensing lectures, screen recordings and travel footage; 0.5x and 0.75x for slow-motion analysis of a sports move or a tutorial step.
You can drop the audio entirely for silent memes and GIF-style loops, or keep it with pitch preserved. Everything is processed on your device; nothing is uploaded.
Where people use the
- Condensing a lecture or meeting recording to skim key points.
- Slow-motion analysis of a technique or a play.
- Making a short clip fit a time limit on social platforms.
How to use the
- 1
Add a video
Drop in a clip. The tool reads its duration so it can show the new runtime before you commit.
- 2
Pick a speed
Choose from 0.25x to 4x presets. The new duration updates instantly.
- 3
Choose audio
Keep audio with pitch preserved, or drop it for a silent result.
- 4
Apply and download
The retimed MP4 is encoded locally and offered for download.
Tips and best practices
- Speeds above 2x read better without audio for talking-head footage.
- The tool reports the new duration before you run it, so you can hit a target length exactly.
Frequently asked questions
Does the audio pitch change?
No. The atempo filter chain stretches time without altering pitch, which is what separates it from simply changing playback rate.
What is the fastest speed?
4x with presets, and the same machinery handles 0.25x slow motion. Extreme speeds may look choppy because frames are duplicated, not synthesised.
Can I make true slow motion?
This tool retimes existing frames. For buttery slow motion you need source footage shot at a high frame rate; the tool can only stretch what exists.
How long does processing take?
About the video's duration at encoding speed. A one-minute clip typically takes under a minute on desktop.