Collaborative Quality-of-Service based video conferencing

Video conferencing typically involves multiple parties who communicate over the Internet by exchanging real-time video and audio messages. The problem about Internet based real-time communication is the best effort behavior which sometimes causes erroneous transmissions that frustrate the conferencing parties. To avoid erroneous transmissions, Quality-of-Service aware video conferencing systems dynamically adapt to varying network conditions for the price of decreased video frame rate, resolution or quality. In this paper we go one step beyond Quality-of-Service awareness and present a collaborative approach for achieving the required quality in video communications that does not require adaptation in the temporal, spatial or quality domain. Instead it reuses cached video frames if the transmission of current frames is not possible. The advantage of reusing cached frames is that the real-time aspect can be maintained for small time periods without sending a single byte of video data over the network. In case of short network failures it is not even possible to realize the difference between the original video and the reused previous frames. We evaluate and compare our frame reusing approach against adaptation in the quality domain which is a well know, but highly CPU intensive and non scalable technique.