Fast forward or
slow it right down.
Pick a speed from 0.25× to 4×, optionally keep audio pitch, and let ffmpeg do the rest — all inside your browser.
Drop your video
Drag and drop any MP4, WebM or MOV file.
Choose speed
Select from 0.25× to 4× and toggle pitch preservation to keep audio sounding natural.
Apply and download
Click 'Apply speed', wait for processing and download your MP4.
What speeds are available?
0.25× (very slow), 0.5× (slow motion), 0.75× (slightly slow), 1.25×, 1.5×, 2× (double speed) and 4× (timelapse).
What does 'Preserve audio pitch' do?
When you slow down or speed up a video, the audio pitch changes naturally (chipmunk effect at 2× etc.). Enabling pitch preservation applies pitch correction so voices and music sound natural at the new speed.
Is my video uploaded?
No. The speed change runs entirely in your browser using ffmpeg.wasm. Your video never leaves your device.
Why does 4× take a long time to process?
ffmpeg must re-encode every frame for speed changes, which is CPU-intensive. A 10-minute video at 4× speed (2.5 min output) may take 5–15 minutes depending on your hardware.
What format is the output?
Output is always MP4 (H.264 video + AAC audio), which is compatible with every device and platform.