Video Speed Tool
Speed a video up or slow it down. You can also give different parts different speeds.
This video has no audio track, so only the picture was converted.
Download converted videoEquivalent FFmpeg command
CLI command for your current settings. Updates live as you change controls.
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=1.000000*PTS,scale=trunc(iw/2)*2:trunc(ih/2)*2[v];[0:a]atempo=1.0000[a]" -map "[v]" -map "[a]" -c:v libx264 -preset fast -crf 23 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart output.mp4What to do next
How to use
- Drop your videoMP4 / MOV / WebM, etc. (up to 500 MB).
- Pick a speedUse a button or the slider. For different speeds in different parts, switch to “Per-segment speed”.
- Choose audio modeThe default, “pitch unchanged”, keeps speech clear. For a higher voice when sped up and a lower one when slowed down, choose “pitch changes too”.
- Run the conversionPreview and download once processing finishes.
Recommended settings
When it goes wrong
The converted video has no sound
Cause: The original video has no audio track (a screen recording made with the microphone off, for example). A video without audio is converted picture-only, whatever the audio setting, and the result says so.
Fix: To add sound, put an audio track on the converted video with the Add BGM / Audio Mix Tool.
Slow-motion stutters
Cause: Slow motion shows each original frame for longer. A 30 fps video at 0.5× plays like 15 fps.
Fix: Use footage shot at 60 fps or more, or pick a speed closer to 1×.
Variable mode plays the same part twice
Cause: Segments overlap. The overlapping part plays in both segments.
Fix: Start each segment at or after the end of the previous one. Gaps between segments play at normal speed.
Questions
Can I keep the original audio pitch?
Yes. The default, “Same speed as the video, pitch unchanged”, uses FFmpeg’s atempo filter to change the speed and keep the pitch, at any speed from 0.25× to 4×.
Variable speed vs. uniform speed?
Uniform applies one factor to the whole video; variable lets you say “0–10 s normal, 10–15 s 0.25×, 15 s on 2×.”
Can I go slower than 0.25×?
The minimum is 0.25×. Run the output through again at 0.25× to get 0.0625×. If it stutters, desktop FFmpeg’s minterpolate can create in-between frames.
Faster than 4×?
The maximum is 4×. Run the output through again at 4× to get 16×.
Why does audio drift?
In every audio mode, this tool keeps the audio and video the same length. If the source is already out of sync, fix it first with the Fix Audio Sync Tool.
Can I reverse playback here?
No. Use the Video Reverse Tool.
More detail (settings, limits, FFmpeg commands)
What each setting means
Browsers and limits
- Maximum file size: 500 MB
- Speed range: 0.25–4×
- Output is H.264 (CRF 23) MP4, with audio re-encoded to AAC 128 kbps
The same job with the FFmpeg command line
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=PTS/2[v];[0:a]atempo=2[a]" -map "[v]" -map "[a]" out.mp4ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=PTS*2[v];[0:a]atempo=0.5[a]" -map "[v]" -map "[a]" out.mp4ffmpeg -i input.mp4 -filter:v "setpts=PTS/4" -an out.mp4