The Media Working Group has published a First Public Working Draft of WebCodecs today. The specification defines interfaces to codecs for encoding and decoding of audio and video. It does not specify or require any particular codec or method of encoding or decoding but provides JavaScript interfaces to implementations of existing codec technology developed elsewhere. Implementers may support any combination of codecs or none at all.

Alongside this main specification, the Media Working Group also published two First Public Working Drafts to establish a registry for WebCodecs:

• The WebCodecs Codec Registry is intended to enhance interoperability among implementations and users of WebCodecs. In particular, this registry provides the means to identify and avoid collisions among codec strings and provides a mechanism to define codec-specific members of WebCodecs codec configuration dictionaries.
• The AVC (H.264) WebCodecs Registration is the first entry in the registry. It describes, for AVC (H.264), (1) the fully qualified codec strings, (2) the VideoDecoderConfig.description bytes, and (3) the codec-specific extensions to the VideoEncoderConfig.

Original source: https://www.w3.org/blog/news/archives/9003