workaround for using x86-only video-calling and WebRTC applications

[pocock]

Consider the following setup:

main workstation:
- POWER9
- GPU
- OBS
- capture hardware

secondary workstation or laptop
- x86
- untrusted OS (e.g. Windows)
- applications that you are required to run for a client or employer (e.g. a messaging or remote desktop app) or a video meeting system that requires WebAssembly

You can generate an RTP video stream from the workstation, receive it on the secondary workstation and make it available as a virtual webcam for the software on that machine

I opened a couple of discussions about the topic:

http://ffmpeg.org/pipermail/ffmpeg-user/2022-August/055275.html

https://obsproject.com/forum/threads/obs-streaming-udp-to-ffmpeg-to-v4l2-loopback.158367/