Change the speed of a video
Speed a video up to 4× or slow it down to 0.25×, with pitch-corrected audio.
Drop a file here or click to browse
Accepts MP4, MOV, M4V, WEBM, MKV, AVI, 3GP. Up to 500.0 MB per file.
Speeding up a tutorial, a cooking clip or a screen recording makes it easier to watch; slowing down a sports move or a pet doing something silly shows what happened. This tool changes the playback speed of the whole video between 0.25× and 4× and writes a new H.264 MP4.
The picture is retimed with FFmpeg's setpts filter. Audio is retimed with the atempo filter, which changes tempo without changing pitch, so voices do not turn into chipmunks at 2× or into slow growls at 0.5×. atempo works best between 0.5× and 2× per pass, so larger changes are applied as a chain of stages (4× is 2× then 2×). When slowing down, frames are repeated rather than invented, so slow motion from a normal 30 fps video looks steppy; footage shot at 60-240 fps slows down much more smoothly.
How to use it
- Drop the video (MP4, MOV, WebM, MKV, AVI or 3GP).
- Set the speed: for example 2× to halve the length or 0.5× for slow motion.
- Choose whether to keep the audio (pitch-corrected) or remove it.
- Click Change speed. The video is re-encoded, so this runs at roughly real-time speed for 720p; then download the MP4.
Frequently asked questions
Will the voice sound high-pitched when I speed it up?
No. The atempo filter keeps the pitch and only changes the tempo. Speech above about 2× becomes hard to follow, though, simply because it is fast.
Why does slow motion look choppy?
A 30 fps video has 30 pictures per second. At 0.25× each picture must be shown four times as long, so movement looks steppy. Record in a high-frame-rate (slo-mo) mode for smooth slow motion.
Can I change the speed of only one part?
Not in one step. Trim the part you want with the Video Trimmer, change its speed here, and keep the other parts as they are.
Is my video uploaded?
No. FFmpeg runs in your browser and the video is processed on your device.
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