Real-time VBR rate control of MPEG video based upon lexicographic bit allocation

The MPEG-2 Video Standard describes in detail a bitstream syntax and a deco der model but leaves many details of the encoding process unspecified, such as encoder bit-rate control. The standard defines a hypothetical decoder m odel, called the Video Buffering Verifier, that can operate in either const ant-bit-rate or variable-bit-rate modes. In this paper, we present a low-co mplexity algorithm for variable-bit-rate control suitable for low-delay, re al-time applications. The algorithm is motivated by recent results in lexic ographic optimal bit allocation. The basic algorithm switches between const ant-quality and constant-bit-rate modes based on changes in the fullness of the decoding buffer in the Video Buffering Verifier. We show how the algor ithm can be applied either to produce a desired quality level or to meet a global bit budget. Simulation results show that the algorithm compares favo rably to the optimal lexicographic algorithm. (C) 1999 Academic Press.