WebM
Also known as: .webm file, how to open webm, WebM video
WebM is an open, royalty-free video container designed for the web, built around the VP8/VP9 (or AV1) video codecs and Opus/Vorbis audio. It is widely used by browsers and sites like YouTube for efficient streaming.
- Open, royalty-free web video container
- Uses VP8/VP9/AV1 video and Opus/Vorbis audio
- Plays natively in browsers; less so in desktop apps
Built for the open web
WebM is a slimmed-down container based on Matroska, created to give the web a format with no licensing fees. Inside, it pairs the VP8, VP9, or newer AV1 video codecs with Opus or Vorbis audio, all of which are open and free to use.
Browsers play WebM natively, which is why it is common for HTML5 video, short animated clips, and adaptive streaming. Outside the browser, support is less universal — some desktop players and editors need it converted first.
Why it is space-efficient
VP9 and AV1 are modern codecs that compress video tightly, so WebM can deliver good quality at a smaller size than older formats. That efficiency is the point: faster page loads and lower bandwidth on the web.
If a WebM clip will not open in an app that expects MP4 or an animated GIF, converting it is straightforward and often produces a smaller, more portable file.