What is the "cheapest" in terms of system load, method of pulling an audio stream?

My goal is to ingest an audio stream - being in opus (same codec used in mediasoup), or in raw PCM audio - into a node.js app on the same host as mediasoup itself.

I could do it by rtp -> ffmpeg in a child process of node app, but this sounds like an exceptionally inefficint detour given that mediasoup runs in the address space of the same node app being a node.js module…

Are there any better options? End result is something like a pipe i read audio data from.

Inspired by this rather cryptic comment by @ibc:

https://groups.google.com/forum/#!topic/jssip/PR_Nh9tLq5M

the raw RTP packets in JavaScript land (Node.js) and use them as you
wish.

which hints on such a possibility…