Encoding to Opus uses unsafe-libopus
and this patch
(actually my fork)
for opus-rs.
Then we glue that together with Symphonia for pure Rust audio decoding,
Rubato for resampling,
and ogg.
You can see this in transcoder/.
transcoder-wasm/ is a simple wrapper that provides JS bindings which gets compiled with wasm-pack.
There's a Svelte demo in transcoder-demo/.
The transcoding is done in a web worker that comunicates with the UI to prevent it from blocking the page while it's working.
You can try it online here.