spadadot writes: I am looking for an open-source solution to allow a user to share his screen in read-only mode with 50+ viewers. For obvious reasons related to bandwidth management, NAT traversals, etc. the video stream must be relayed by a central server. Finally, the central server must also be able to record the video stream to a file. Bonus points if the presenter can share only one of his screens or a portion of a screen and if it is multi-platform on both sides. Has anyone already tried it? Was it build on top of VNC? WebRTC?