Experiences with Interactive Video Using TFRC

I gave a presentation on our experiences with interactive video using TFRC to the Datagram Congestion Control Protocol (DCCP) working group at the 66th IETF meeting in Montreal, Canada, on 12 July 2006.

In this presentation, I outlined the TFRC implementation we built as part of the UltraGrid system, and the challenges inherent in achieving accurate packet spacing at the sender, and sufficiently timely feedback from the receiver. I then highlighted the impact these have on the stability of the TFRC protocol, especially over local-area connections with relatively short round-trip times.

The talk also considered issues with slow-start for video, and difficulties with matching the output rate of a codec to the desired rate of a congestion control algorithm. One conclusion is that window-based congestion control may be a better fit for Internet video than rate-based congestion control.