This tool is part of the Pro suite. Free users can preview but cannot export.
Subscription tier limits
Up to 953.7 MB
Batch: 1 file
Upgrade required
Up to 9.31 GB
Batch: 5 files
Up to 93.13 GB (streamed)
Batch: 50 files
Hardware-accelerated via WebCodecs / WebGPU on supported browsers (Chrome, Edge, Safari 17+).
Drop your video and pick a target speed
JAD time-stretches audio (atempo) and adjusts video PTS
Hardware-encode the result and ship it to disk
0 bytes uploaded. Video Speed Controller (0.25× to 4×) runs entirely in your browser using WebCodecs, WebGPU, and FFmpeg.wasm. Pro + Media uses chunked streaming via the File System Access API — your video is never buffered to RAM in full and never leaves your machine.
No — audio passes through atempo for pitch-preserving time stretching. The chipmunk effect only happens when you skip atempo.
0.25× (quarter speed) to 4× (4x faster). Outside this range, atempo gets chained which sounds worse than just doing the cut differently.
Cut MP4, MOV, MKV, and WebM files without quality loss. Stream-copy mode keeps original codec, original quality, and finishes in seconds.
Open toolConvert between MP4, MOV, MKV, WebM, AVI, M4V, TS, and ProRes locally. Hardware-accelerated H.264/H.265/AV1 when available.
Open tool