WebM is an audio-video format designed to provide a royalty-free, high-quality open video compression format for use with HTML5 video. The project’s development is sponsored by Google.
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, concerns have surfaced over potential for infringement on existing patents and some in the industry have called upon Google to provide indemnification against patent suits.