Fast Intra Mode Decision Algorithm Based on Spatial-Domain Energy for H.264/AVC

In this paper, we proposed a fast intra mode decision algorithm based on spatial-domain energy for H.264/AVC. First of all, the relevance between macroblock (MB) and its 4x4 sub-blocks is employed in our algorithm to determine the Intra prediction block size. And then, in order to further reduce the computational complexity of Intra mode decision radically, mode candidate reduction algorithm is released by using the information abstracted from the MB or its sub-blocks. Compared with H.264 reference software, the proposed algorithm maintains the encoding performance efficiently by slight decrease in PSNR and increase in Bitrate. However, it achieves above 84% reduction of computation complexity in average.