Video Speed Changer
NewSpeed up or slow down your video's playback rate while keeping the audio in sync.
Your files are processed entirely in your browser. Nothing is uploaded to any server, and your documents never leave your device.
What is Video Speed Changer?
A video speed changer re-times a video so it plays faster or slower than it was recorded, from quarter speed slow motion to 4x fast forward. Unlike simply changing playback speed in a player, this tool permanently re-encodes the video with FFmpeg in your browser, adjusting the audio tempo to match so voices stay natural in pitch and perfectly in sync. The result is a normal video file that plays at the new speed everywhere.
Why use Nuo Tools's Video Speed Changer?
How to use Video Speed Changer
Drop your video into the tool.
Pick a speed - presets from 0.25x to 4x, with the current choice previewed.
Click Apply and wait while the video and audio are re-timed together.
Download the speed-adjusted MP4.
Frequently asked questions
Does the audio stay in sync?+
Yes. The video timing and audio tempo are changed together in one pass, so they remain perfectly aligned at any speed.
Will voices sound like chipmunks when sped up?+
No. The tool changes audio tempo, not pitch - voices speak faster or slower but keep their natural tone.
What speeds are supported?+
Presets cover 0.25x, 0.5x, 0.75x, 1.25x, 1.5x, 2x, 3x, and 4x - the full practical range for slow motion and fast forward.
Does slowing down video add new frames?+
No new frames are invented - each original frame is simply shown longer, which is how standard slow motion works. Footage recorded at high frame rates slows down most smoothly.
Is my video uploaded?+
No. The re-timing runs in your browser through FFmpeg compiled to WebAssembly. The file never leaves your device.
When to use this tool
- →Speeding up a tutorial or lecture recording to review it faster
- →Slowing down a sports or technique video to study the motion
- →Creating a time-lapse feel from a long static recording
- →Slowing a fast demo so viewers can follow each step
- →Fitting a long clip into a time-limited slot by playing it faster