16x16 Macroblock partition size prediction for H.264 P slices

Abstract

H.264 uses variable block sizes for macroblock partition. The H.264 encoder allows 2 intra coding modes and 5 inter coding modes for a macroblock in a P slice. This is the most essential part for high compression efficiency but requires many computations to decide the most suitable coding mode. In this paper, we present a fast mode decision algorithm for H.264 P slices. To reduce complexity, we analyze the results of P16x16 ME (motion estimation) of a macroblock according to the proposed decision model, and if this macroblock is considered to be coded with a larger mode, we prevent motion estimations for smaller modes. From statistical analysis, we define a decision model which estimates whether the macroblock partition size is further divided or not. Our experimental results show that the proposed algorithm can achieve 11 similar to 63% computational savings without significant degradation of visual quality and increase in bit rate.(1)