Digital television on ATM networks: how to optimize coding and transmission?

摘要

Abstract: This paper aims at presenting the major steps towards the elaboration of an optimum control for video transmissions on ATM network. The paper puts forward the gain in statistical multiplexing to demonstrate that transmitting at variable rates on asynchronous multiplexing links is more efficient than exploiting constant rate on synchronous links. Optimum coding and transmission require to characterize the video sources of information as entropy generator and the develop entropy rate-distortion functions in the coder and the transmission channel. Quantizers and VLC in coding, traffic and queues in transmission multiplexing lead each to performance functions expressing quality in terms of entropy rate; they are respectively the PSNR in function of the output data rate and the cell losses in terms of the network loads. The main advantage of transmitting on variable bit rate channels is to favor the generation of image sequences at constant subjective quality on the coding side, and, the saving of transmission bandwidth through a gain in statistical multiplexing on the network side. Mirror control algorithms can be implemented in the coding end and in the multiplexing nodes to optimally manage the rate-distortion functions.!5