How to use
- Drop your WMV file on the box.
- Keep MP4 selected. Choose a lower resolution or “Small file” to make the result smaller.
- Press Convert. WMV must be re-encoded, so allow a few minutes for longer videos.
About WMV
WMV (Windows Media Video) was Microsoft’s video format in the 2000s and was used by many cameras, screen recorders and Windows Movie Maker. Apple devices and most browsers can’t play it. Converting to MP4 with H.264 video and AAC audio makes the file playable almost everywhere. This tool can also convert videos to WMV for older Windows software.
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.
Why does my WMV fail to convert?
WMV files protected with Windows Media DRM can’t be converted by any free tool.