Enlarged Block Sizes and Motion Search Ranges for High Definition Video Coding

A rate-distortion (R-D) model is derived to investigate the potential coding gain from the use of a larger macroblock size for high definition (HD) video coding in this work. Coding rates of using different block sizes for HD video coding are compared with the R-D model, and limitations of the current coding techniques that might impede the additional R-D gain of using enlarged MB for HD coding are explained. Experiments show that an average bit rate gain of 27 % across QP range can be achieved by using enlarged MB and extended motion search range.