LibAV WASM

This library can be used to remux from MKV -> MP4, it could technically do any remux but i haven't had the need for it, create an issue if you'd like it.

src/test.ts
Contains a full example of a MKV video player

Basic usage
``ts
const remuxer = await makeRemuxer({
// the path at which the wasm file is getting served
publicPath: new URL('/dist/', new URL(import.meta.url).origin).toString(),
// url of the worker file of libavWASM
workerUrl: new URL('../build/worker.js', import.meta.url).toString(),
// reads will be done in 2.5mb chunks
bufferSize: 2_500_000,
// byte length of the video file
length: contentLength,
// fetch returning a ReadableStream
getStream: async (offset, size) =>
fetch(
VIDEO_URL,
{
headers: {
Range: bytes=${offset}-${size ? Math.min(offset + size, contentLength) - 1 : ''}
}
}
).then(res => res.body)
})

// returns the header of the video with all the metadata
const header = await remuxer.init()

// Returns a chunk that looks like {
// offset: number,
// buffer: Uint8Array,
// pos: number,
// pts: number, // timestamp
// duration: number
// }
// buffer can be appended to the MediaSource API(MSE API)
const chunk = await remuxer.read()

// allows you to seek to timestamp and start reading from there
const seekChunk = await remuxer.seek(number)
// ...
`

Intellisense

To have C++ autocompletion, put a ffmpeg repo clone folder in the root
git clone https://github.com/FFmpeg/FFmpeg & git clone https://github.com/emscripten-core/emscripten

Issues to fix / features to implement

- Try to play around with sourceBuffer.timestampOffset = res.pts` and always increasing timestamps to not have to re-init on backwards seeks
- Transcoding
- Base transcoding off of https://cconcolato.github.io/media-mime-support/#audio_codecs