Change Video Speed
Upload a video and change its playback speed — from 0.25x slow motion to 4x fast forward. The tool adjusts both the video frame rate (using ffmpeg's setpts filter) and the audio pitch/tempo (using the atempo filter) so everything stays synchronized. The audio pitch shifts naturally with the speed change, just like fast-forwarding or rewinding a tape.
This is useful for creating time-lapses from long recordings, adding slow-motion effects to action clips, speeding through tutorials or lectures, or adjusting pacing for social media content. Extreme slow motion (0.25x) will make a 10-second clip 40 seconds long, while 4x speed compresses it to 2.5 seconds.
Everything runs in your browser using ffmpeg.wasm — your video is never uploaded to a server.
By The Paper Room Editorial Team — Video Tools
Frequently asked questions
What speed should I use for a time-lapse effect?▼
For a subtle time-lapse, try 2x or 3x. For a dramatic time-lapse of a long event, 4x is the maximum this tool supports. The best speed depends on the content — a 30-minute cooking video at 4x becomes about 7.5 minutes.
Does the audio change pitch when I change speed?▼
The audio tempo changes with the speed — faster playback means higher-pitched audio, slower means lower-pitched. This is the natural behavior, similar to fast-forwarding a tape. If you want to remove the audio entirely, use the Mute Video tool first.
Why is the slow-motion minimum 0.25x?▼
At speeds below 0.25x, the video would need to interpolate frames that don't exist in the source, which this browser-based tool doesn't support. For smoother slow motion, you'd need a tool that can generate intermediate frames using optical flow or AI.