How to use
- Drop a video on the box or choose one. The converter loads the first time (about 31 MB).
- Pick the output format. For MP4 and MOV, H.264 videos are copied without re-encoding when possible, which takes seconds.
- Optionally set quality, resolution, start and end times, or remove the audio.
- Press Convert, preview the result and download it.
Supported formats
| Input | Output |
|---|---|
| MP4, MOV, M4V, WMV, ASF, AVI, MKV, WebM, FLV, 3GP, MPEG, TS | MP4 (H.264), MOV (H.264), WebM (VP8), WMV (WMV2), GIF, MP3, M4A (AAC), WAV |
Open-source software
Conversion is done by FFmpeg compiled to WebAssembly by ffmpeg.wasm (MIT). The FFmpeg core used here includes components licensed under the GPL; their source code is available from those projects. The converter (about 31 MB) is downloaded from the jsDelivr CDN the first time you convert, then cached by your browser.
Frequently asked questions
Is my video uploaded?
No. The video is processed by your browser on your own device. Only the converter program itself is downloaded.
Why is it slower than desktop software?
Browsers run the converter on a single CPU core without hardware acceleration. Converting a 1-minute 720p video usually takes one to a few minutes. Copying H.264 into MP4 or MOV without re-encoding takes seconds.
Is there a size limit?
There is no fixed limit, but browsers can only use a few GB of memory. Files up to a few hundred MB usually work; very long or 4K videos may fail.
Can it convert copy-protected videos?
No. Videos protected with DRM, such as some purchased or rented movies, can’t be converted.