The Missing Protocol: How BFCP Unlocked Dual-Monitor Conferencing for Enterprise Room Systems

Enterprise room systems with dual monitors couldn't properly separate video and screen share when connecting through SIP gateways due to OpalVoIP's lack of BFCP support. The author implemented BFCP from scratch in 2018 by integrating libbfcp via C++, extending SDP offer/answer processing, and designing a dual-role client/server architecture. The write-up covers SDP negotiation details, pre-negotiation vs mid-call renegotiation tradeoffs, and how WebRTC handles content sharing differently.