WebCodecs

The WebCodecs API allows web applications to encode and decode audio and video.

Many Web APIs use media codecs internally to support APIs for particular uses:

• HTMLMediaElement and Media Source Extensions
• WebAudio (decodeAudioData)
• MediaRecorder
• WebRTC

But there’s no general way to flexibly configure and use these media codecs. Because of this, many web applications have resorted to implementing media codecs in JavaScript or WebAssembly, despite the disadvantages:

• Increased bandwidth to download codecs already in the browser.
• Reduced performance
• Reduced power efficiency

It's great for:

• Live streaming
• Cloud gaming
• Media file editing and transcoding

See the explainer for more info.

Code samples

Please see https://w3c.github.io/webcodecs/samples/

WebCodecs registries

This repository also contains two registries:

• The WebCodecs Codec Registry provides the means to identify and avoid collisions among codec strings used in WebCodecs and provides a mechanism to define codec-specific members of WebCodecs codec configuration dictionaries. Codec-specific registrations entered in the registry are also maintained in the repository, please refer to the registry for a comprehensive list.

• The WebCodecs VideoFrame Metadata Registry enumerates the metadata fields that can be attached to VideoFrame objects via the VideoFrameMetadata dictionary. Metadata registrations entered in the registry may be maintained in this repository or elsewhere. Please refer to the registry for a comprehensive list.