What is a WebM file?
WebM is an open, royalty-free video format that Google launched in 2010 for the web. It is a simplified form of the Matroska (MKV) container that only allows open codecs: VP8, VP9 or AV1 for video and Vorbis or Opus for audio.
Every modern browser plays WebM, and browsers also record to it: screen recorders, voice and video recorders built on the MediaRecorder API, and many online meeting tools save .webm files. Outside the browser it is less welcome. Some video editors, older iPhones, smart TVs and social networks will not take it, which is why the most common thing people do with a WebM is convert it to MP4.
WebM at a glance
| Full name | WebM (based on Matroska) |
|---|---|
| File extensions | .webm |
| Created by | |
| Introduced | 2010 |
| Compression | Lossy (VP8, VP9 or AV1) |
| Codecs inside | VP8, VP9 or AV1 video; Vorbis or Opus audio |
| Opens on | Every current browser and Android; many editors, older iPhones and TVs do not play it |
| Best for | Video on websites and browser screen recordings |
How to open a WebM file
Drag a WebM into Chrome, Edge or Firefox to play it, or use VLC. To share or edit it, convert it with WebM to MP4; to keep just the sound, use WebM to MP3.