WebM is a video file format intended primarily for royalty-free use in the HTML-5 video tag. The WebM Project releases WebM-related software under a BSD (Berkeley Software Distribution, a Unix-like operating system) license and all users are granted a worldwide, non-exclusive, no-charge, royalty-free patent license. WebM files consist of video streams (as well as metadata including subtitles and closed captioning) compressed with the VP8 video codec and audio streams compressed with the Ogg Vorbis audio codec. WebM is a royalty-free alternative to the patented H.264 codec (which powers everything from online videos to Blu-Ray discs) and MPEG-4 standards, and is suitable for commercial and non-commercial applications. WebM files use a .webm file extension.
WebM videos can also be easily coded to autoplay and endlessly loop without an additional video player, which makes them a potential competitor to the GIF, which currently reigns supreme for easily-shared, easily-embedded animations. WebM file structure is sponsored by Google and was first unveiled in 2010. The WebM container is based on a profile of Matroska, which stores video in .mkv files. WebM initially supported VP8 video and Vorbis audio streams and in was updated to accommodate VP9 and Opus audio.
VP8 is a highly efficient video compression technology that was developed by On2 Technologies. Google acquired On2 in February 2010. Vorbis is an open-source audio compression technology. It is an independent project of the Xiph Foundation.
WebM was built for the web. After testing hundreds of thousands of videos with widely varying characteristics, it was found that the VP8 video codec delivered high-quality video while efficiently adapting to varying processing and bandwidth conditions across a broad range of devices. The relative simplicity of VP8 makes it easy to integrate into existing environments and requires comparatively little manual tuning in the encoder to produce high-quality results, excellent for the sharing and archiving of filmed and audio material, as well as for such uses as quick reference and transcription.
WebM video plays directly in your web browser using HTML-5. No plug-ins are needed, but a modern web browser that supports HTML-5 and WebM is required. YouTube is supporting WebM in addition to its existing formats as part of its HTML-5 experiment.
WebM is supported by Mozilla Firefox 4 and later versions, Opera 10.60 and later versions, Google Chrome 6 and later versions, and Microsoft Internet Explorer 9 and later versions. Other media players and components that support WebM include jetAudio Basic, Media Player Classic, Moovida Core, Perian, VLC, Winamp and XBMC.