WebM is an audio-video format designed to provide royalty-free, open video compression for use with HTML5 video. The project's development is sponsored by Google Inc.
A WebM file consists of VP8 video and Vorbis audio streams, in a container based on a profile of Matroska. The project releases WebM related software under a BSD license and all users are granted a worldwide, non-exclusive, no-charge, royalty-free patent license. Despite this, some in the industry have called upon Google to provide indemnification against patent suits.
Openness and innovation. A key factor in the web's success is that its core technologies such as HTML, HTTP, and TCP/IP are open for anyone to implement and improve. With video being core to the web experience, a high-quality, open video format choice is needed. WebM is 100% free, and open-sourced under a BSD-style license.
Optimized for the web. Serving video on the web is different from traditional broadcast and offline mediums. Existing video formats were designed to serve the needs of these mediums and do it very well. WebM is focused on addressing the unique needs of serving video on the web.
Low computational footprint to enable playback on any device, including low-power netbooks, handhelds, tablets, etc.