I did a prototype of a 3D low-latency server side mixing system, based on a hypothetical 4k clients, @48k each being mixed with the 64 loudest clients.. Using Opus, forced to Celt mode only and running 256 stereo sample frames at 128kbps.. Worked well, using only 6 cores for that workload.. The mixing was trivial, but the decode and encode of 4k streams was entirely doable.. This issue at that rate was 1.5M network packets a second.. If I was to revisit it, I’d look at using a simple MDCT based codec, with a simple Psychacoustic model based on MPC (minus CVD) and modified for shorter frames + Mdct behaviour versus PQMF behaviour, without any Huffman coding or entropy coding.. And put that codec on the GPU.. Small tests I did using a 1080ti indicated ~1M clients could be decoded, mixed and encoded (same specs as above) problem is then how to handle ~370M network packets a second :)
Edit: Had high hopes for High Fidelity, and came very close to asking for a job there ;) Shame it’s kaput, didn’t know that :(