Robust handling of sudden changes of bandwidth in selective forwarding unit conferences

A multimedia system for handling a decrease in available egress bandwidth to a first participant device among a plurality of participant devices, comprising:

• a media server having a selective forwarding unit (SFU) architecture,
• wherein the media server includes processing circuitry configured to execute program instructions out of a memory:
• to detect the decrease in the available egress bandwidth to the first participant device, a second participant device among the plurality of participant devices currently sending a video stream at a transmission bitrate to the media server for forwarding to the first participant device over an egress network;
• to send a first request to the second participant device to reduce the transmission bitrate;
• to determine whether to reset the forwarding of the video stream currently being sent by the second participant device to the first participant device;
• having determined to reset the forwarding of the video stream currently being sent by the second participant device to the first participant device, (i) to stop the forwarding of the video stream from the second participant device to the first participant device, and (ii) to send a second request for an I-frame to the second participant device for use in restarting the forwarding of the video stream from the second participant device to the first participant device;
• and
• having received the requested I-frame from the second participant device, to restart the forwarding of the video stream from the second participant device to the first participant device.

A computer program product including non-transitory, computer-readable media having instructions that, when executed by control circuitry of a computerized apparatus, cause the control circuitry to perform a method of handling a decrease in available egress bandwidth from a media server having a selective forwarding unit (SFU) architecture to a first participant device among a plurality of participant devices, the plurality of participant devices being communicably coupled to the media server, the method comprising:

• detecting, by the media server having the SFU architecture, the decrease in the available egress bandwidth to the first participant device, a second participant device among the plurality of participant devices currently sending a video stream at a transmission bitrate to the media server for forwarding, by the media server, to the first participant device over an egress network;
• sending a first request, by the media server, to the second participant device to reduce the transmission bitrate;
• determining whether to reset the forwarding of the video stream currently being sent by the second participant device to the first participant device;
• having determined to reset the forwarding of the video stream currently being sent by the second participant device to the first participant device, stopping the forwarding of the video stream from the second participant device to the first participant device, and sending a second request for an I-frame to the second participant device by the media server for use in restarting the forwarding of the video stream from the second participant device to the first participant device;
• and
• having received the requested I-frame from the second participant device, restarting the forwarding of the video stream from the second participant device to the first participant device.