Design and performance evaluation of a variable bit-rate (VBR) video compression algorithm for ATM networks

The authors present the design and performance evaluation of a robust, DCT-based (discrete-cosine-transform-based) variable-bit-rate (VBR) compression algorithm for use on B-ISDN/ATM networks. The algorithm class under consideration is based on a recent proposal by F. Kishino et al. (1989), intended to provide robust delivery of video under relatively high ATM cell loss conditions. The robust VBR codec is based on separation of subjectively important low-frequency DCT coefficients (for high-priority transport) from the less important high-frequency coefficients (which are sent at a lower priority level). Temporal propagation of error after loss of low-priority ATM cells is avoided by limiting interframe prediction to low-frequency information transmitted in high-priority cells. Several key questions that arise in the design of such an ATM codec are considered, including: (a) the trade-off between total bit-rate and robustness; (b) the influence of the high/low priority boundary parameter on the high-priority and low-priority bit-rates; and (c) performance at the decoder in the presence of ATM channel loss