What software do providers use to broadcast a video stream?

Question

Video broadcast

I conceived a project that would allow connecting client rtsp streams to my own server via vpn and broadcasting in various formats on the site (personal account). In addition, keep a record of the flow for certain periods of time.
I can write my own web interface without any problems, however, I have no idea what software to use to receive and broadcast streams. Clients can be from 1 to 1000. All that I found on forums and Google are strange methods with vlc and ffmpeg, or some strange foreign software, sharpened for narrow directions.
Interested in what software do ISPs use to organize broadcasting? For example, the cloud.bitrace.ru project

Answer 1

Here I briefly listed the options.

Answer 2

to receive avconv-ffmpeg
to serve wowza, nginx-rtmp, erlyvideo, ...

Answer 3

Microsoft MediaRoom