Video
Turn your MP4 files into WebM in seconds. Everything happens in your browser: nothing is uploaded to any server.
Drag your files here
Or paste them with Ctrl+V. They never leave your device.
At equal quality it takes slightly more space than a WebM with VP9. As WebM (VP9) it is lighter and plays directly in browsers.
MP4 is the most widespread video container; here it comes out with H.264 video and AAC audio, the most compatible combination.
Strengths: It plays on any phone, TV, browser or social network without installing anything.
Limits: At equal quality it takes slightly more space than a WebM with VP9.
WebM is an open, patent-free video format made for the web; here it comes out with VP9 video and Opus audio.
Strengths: It compresses very well and plays directly in Chrome, Firefox, Edge and recent Safari.
Limits: Editing programs, TVs and old phones often cannot open it.
No. The MP4 to WebM conversion runs entirely in your browser, with code downloaded from this site and executed on your device. You can check it in the Network tab of the developer tools or by going offline after the page loads.
It depends on the length, the resolution and your computer. The browser’s hardware acceleration is used when available, and you get an estimate before it starts.
Up to 2 GB and 3 hours of video on desktop; on mobile, 500 MB and 30 minutes (AVI: 1 GB and 1 hour on desktop). If it is over, you are told before it starts and can trim it.
Yes. Drop as many MP4 files as you like: several are converted at the same time, depending on your processor cores, and when they finish you can download each WebM or all of them in a ZIP.