Real-time audio/video conferences in Linphone using a modern SFU server

Conference Description:

“Multipoint Control Unit” (MCU) or “Media Mixing Mixer” video conferencing solutions have proven to be resource-intensive due to the complexity of video codec algorithms. This limitation led to the emergence of new solutions that transmit only a useful subset of the streams received from all participants to each participant. For example, only the video of the active speaker (the person talking) is broadcast to all participants, accompanied by very low-resolution video streams of the other participants. This technology is called “Selective Forwarding Unit” (SFU) or “Selective Forwarding Middlebox” (SFM). These solutions pave the way for conference sessions managed by a server that does not decode media content. The main advantage of an SFU is its ability to receive multiple media streams and decide which ones should be sent to each participant, thus increasing the number of participants in a group call.

Linphone could be the first open-source SIP-based conference solution using a modern SFU server. Since the server solution already used for instant messaging was compatible with open standards for managing chat rooms and their participants, the idea was to enhance this component by adding media management capabilities. The Linphone team developed an SFU algorithm based on mediastreamer2 and ortp (Linphone’s media processing libraries) in a new software component called “MS-SFU.”

🇬🇧 This conference is in English.