Schulzki What do you think, is it worth to continue from here?
It looks promising.
Is there some place where I could browse the source code?
I have not started any development related to this feature myself, so it is great to see a working prototype.
Have you considered using WebRTC? Maybe my concerns are not justified, but I would tend to have the least possible work done by the server. As far as I understand, in WebRTC, the server is only involved in the "signaling" part, and the actual communication between the presenter and the viewers is peer-to-peer.