Models for packet switching of variable-bit-rate video sources

Packet switching of variable-bit-rate real-time video sources is a means for efficient sharing of communication resources while maintaining uniform picture quality. Performance analysis for the statistical multiplexing of such video sources is required as a first step towards assessing the feasibility of packet video. This paper extends our earlier work in modeling video sources which have been coded using interframe coding schemes and in carrying out buffer queueing analysis for the multiplexing of several such sources. Our previous models and analysis were suitable for relatively uniform activity scenes. Here, we consider models for scenes with multiple activity levels, which lead to sudden changes in the coder output bit rates. We present correlated Markov models for the corresponding sources, and using a flow-equivalent queueing analysis, obtain common buffer queue distributions and probabilities of packet loss. Our results demonstrate the efficiency of packet video on a single link, due to the smoothing effect of multiplexing several variable-bit-rate video sources.