Video to WebM converter
Make a WebM video, the open format for the web, from an MP4 or MOV. It is re-encoded on your device.
How it works
The video is read by ffmpeg.wasm and re-encoded as VP8 video with Vorbis sound, inside a WebM container.
Re-encoding takes time: a few seconds for a short clip, longer for a long one.
Your files never leave this device. The video engine is downloaded once from jsDelivr the first time you convert a video, then the browser keeps it.
Your files stay on this device. Nothing is uploaded, and the converter runs entirely in your browser.
Questions
Why re-encode instead of copying?
WebM only holds VP8 or VP9 video and Vorbis or Opus sound, so an H.264 video has to be converted.
Will the sound be kept?
Yes. The sound is re-encoded as Vorbis at 96 kbps.
Are files uploaded?
No. The converter runs on this device. Only the engine itself is downloaded once.