Very Low Bit-rate HDTV Encoding Scheme based on MPEG-2 Optimum Coding

Abstract

This paper describes a high compression MPEG-2 encoding scheme for distributing HDTV programs at a bit-rate of up to 15 Mbps that can be used for digital terrestrial broadcasting in Japan. Obtaining an adequate picture quality in broadcasting at such a low bit-rate by using conventional MPEG-2 coding scheme is impossible.We thus developed optimum coding for the picture and macroblock layer, i.e. scene adaptive picture type assignment and optimum selection of macroblock coding modes. In the scene adaptive picture type assignment, the characteristics of input HDTV signals are analyzed prior to actual encoding. The optimum selection of macroblock coding modes is used to encode each macroblock to minimize the source information while preserving the target picture quality. This new scheme can be used with MPEG-2 standards and it is compatible with any MPEG-2 decoder. Experiments using various motion pictures showed that the proposed optimum MPEG-2 encoding scheme significantly improves encoding and can thus be used for digital terrestrial broadcasting in Japan.