Convert video
Real FFmpeg, running on your machine inside the browser. Drop a video, choose the format and quality, and get the file back without it ever reaching a server.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Drop a video file.
- Choose the output format, quality (CRF), resolution and frame rate.
- Start, and download the result when the encoder finishes.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see are the tool’s own code and, once cached, none at all.
Frequently asked questions
What does CRF mean?
Constant Rate Factor: the quality target. Lower is better quality and a bigger file. For H.264, 18 is visually lossless, 23 is the usual default and 28 is noticeably soft. It adapts the bitrate per scene, which is why it beats picking a fixed bitrate.
Why is it slower than a desktop program?
Because it is FFmpeg compiled to WebAssembly rather than native code, and because a browser tab gets a fraction of your machine. This page is served with cross-origin isolation headers so ffmpeg can use several threads, which recovers most of the difference — but a native encoder will still win.
Is my video uploaded?
No. FFmpeg itself is compiled to WebAssembly and runs inside this tab; the file is read from disk into memory and the result is written back out. Nothing is transmitted, which is why a two-hour film will not work here — your device is doing all of it.