Buffered rate-distortion control of MPEG compressed video channel for DBS applications

A joint rate-distortion control algorithm of multichannel sources is proposed to control the overall picture quality by putting some constraints on the encoder´s quantization parameters and buffer state to allow a limited variable bit rate (VBR) coding within a group of pictures (GOP) block. A major drawback for video transmission over a conventional fixed rate channel without using a VBR encoder is that received picture quality varies greatly, resulting in non-uniform subjective perception. In order to minimize these effects buffered-constrained rate-distortion control within a GOP block level finds an optimal solution in a combined rate-distortion sense by permitting a VBR encoding as well as the direct feedback of the buffer state into the cost measure when multichannel programs are statistically multiplexed. Results indicate some quality gains over the conventional constant bit rate method