There are 3 repositories under mediasource-extensions topic.
WebAssembly-based (Rust) & in-worker HLS Media Player for the web
Appending videos in JavaScript with appendBuffer. See blog post for more details.
WebCodecs Opus Recorder/Media Source Extensions Opus EncodedAudioChunk Player
调研游览器对 Media Source Extensions 兼容情况.
A JavaScript library for adaptive video streaming.
wsfmp4.js is a JavaScript library designed to play fragmented mp4 format video data transmitted via WebSocket in browsers that support MSE.