I wish there was a better way to scale receiver feedback. It is very hard/impossible to scale without the server saving every frame and being able to come up with the frames as needed.
What is receiver feedback?
It's an umbrella term for a bunch of mechanisms where the receiver can tell the sender about things like dropped packets, congestion etc. So the sender can adjust the stream accordingly.
kabes description is excellent. It just gives senders lots of info about receivers. Since it is WebRTC all the way through this is possible.
You can read about it in more detail https://webrtcforthecurious.com/docs/06-media-communication/
Instead of doing fixed interval keyframe we can use receiver feedback (Massive reduction in bandwidth)
Instead of server side generated transcodes we can use Simulcast. Will be better quality AND massively reduced server load.
If anyone wants to use with Pion check out https://github.com/Glimesh/broadcast-box
Then run `ffmpeg -re -f lavfi -i testsrc=s=1280x720:r=30 -f lavfi -i sine=f=440:b=4 -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -r 25 -g 50 -acodec libopus -ar 48000 -ac 2 -f rtc -authorization "STREAM_NAME" "http://localhost:8080/whip"