Video converter & compressor
Convert, shrink and trim video, turn clips into GIFs, or pull out the audio as MP3. It runs ffmpeg on your own device, so even large private videos never leave your computer.
The converter (32 MB) downloads once from this site when you press Convert.
ffmpeg log
Your video is processed on your device by ffmpeg.wasm, loaded from this site. It is never uploaded — open the Privacy check at the bottom of the page to watch.
Shortcuts
Why convert video in the browser?
Most online converters upload your video to their servers, which is slow for big files and risky for private ones. This tool runs FFmpeg — the engine behind most video software — compiled to WebAssembly (ffmpeg.wasm) inside your browser. The 32 MB engine is downloaded once from this site and cached; your video is read directly from your disk and never sent anywhere.
Speed and limits
- Browser encoding is slower than desktop software — roughly real-time for 720p MP4 on a recent laptop, slower on phones.
- Very large files (over about 2 GB) can exceed browser memory. Trim first, or use desktop software.
- MP4 output uses H.264 + AAC; WebM uses VP8 + Vorbis for speed.
Need captions for the video? Get a transcript with offline transcription, then save it as SRT.
Frequently asked questions
Is my video uploaded?
No. ffmpeg runs in your browser tab and reads the file from your device. The page’s security policy doesn’t allow it to send data anywhere; the Privacy check lists every request.
Why is the first conversion slow to start?
The converter engine (32 MB) downloads once from this site. After that it’s cached by your browser.
Which formats can it read?
Almost anything FFmpeg supports: MP4, MOV, WebM, MKV, AVI, FLV, 3GP and more, including HEVC iPhone videos.