API that 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.