Fast three step intra prediction algorithm for 4x4 blocks in H.264

Abstract

This paper presents a fast three step algorithm for H.264 4x4 intra prediction. Motivated by the highly correlation of RD cost between different prediction direction, in each step of the algorithm, the proposed algorithm efficiently explores the neighborhood direction around the minimum one and thus skips other unlikely ones. Thus, the proposed algorithm can complete 4x4 intra prediction by only examining 6 modes instead of 9 modes in the full search algorithm. The simulation result shows that the proposed algorithm can maintain the similar PSNR quality to the full search algorithm with only about 1% bit-rate increase.