webm

WebM is an open, royalty-free media container format designed for the web. It is based on the Matroska container format and intended to provide a simple, openly licensed option for web video and audio streams. WebM was introduced by Google in 2007 as part of an effort to promote open standards for the web, with the first widely released specification and tooling appearing in the late 2000s.

The container supports multiple video and audio codecs, with VP8 and Vorbis originally forming the core pair. Later developments added VP9 and Opus for improved quality and efficiency, and more recent updates have introduced support for AV1 in the WebM ecosystem. A WebM file multiplexes video and audio streams into a single binary file. The container itself uses the EBML (Extensible Binary Meta Language) framework, derived from Matroska. The typical file extension is .webm and the MIME type is video/webm.

Adoption and usage: WebM is designed for seamless integration with the HTML5 video element, and it is natively supported by major web browsers such as Google Chrome, Mozilla Firefox, Microsoft Edge, and Opera, enabling playback without plugins on most platforms. It is commonly used for online video hosting, user-generated content, and streaming scenarios where an open, license-friendly format is advantageous.

Licensing and status: The WebM project aims for royalty-free usage on the web. While the container and reference implementations are available under permissive licenses, individual codecs (e.g., VP9, AV1, Opus) may have separate licensing considerations in some contexts. The format continues to evolve, with ongoing enhancements to codec support and tooling.