Change Video Speed
Speed up or slow down a clip, keeping the audio in step with the picture.
Fill in the form and press “Change speed” to see the result here.
How to use it
- 1Choose your file, or drag it onto the upload area.
- 2Set the options. Every setting is a fixed choice, which is what keeps the conversion safe to run.
- 3Press the button. The job is queued and the page shows it move through waiting, processing and ready.
- 4Download the result. Both your upload and the result are deleted once you have it.
About the Change Video Speed
Both the picture and the sound are retimed, so they stay together. The audio is time-stretched rather than resampled, so voices keep their pitch.
Slowing a clip down repeats frames; it cannot create motion that was never filmed. Genuine slow motion needs a high frame rate at the time of recording.
Questions people ask
What actually does the work?
FFmpeg, the same open-source toolchain most video software is built on. It runs as a separate process with a fixed argument list, a time limit and no network access. Nothing from your filename or your settings is ever passed to a shell.
Why does this one take longer than the other tools?
Media work is genuinely expensive: a re-encode reads and writes every frame. The job is queued so that a busy moment slows things down rather than taking the site out, and the page shows where your job is in that queue.
What happens to the file I upload?
It is stored under a random name that is not guessable, processed by an isolated worker, and deleted as soon as you download the result - and in any case automatically after 60 minutes. Uploads are never indexed, shared or used for anything besides producing your result.
Is it free, and do I need an account?
Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.