A Multi-stage Fast Intra Mode Decision Algorithm in H.264

H.264/AVC is a high performance video coding standard with higher compression and better network compatibility, which not only has important theoretical value but also shows wild application prospect. In order to reduce its computational complexity and achieve real-time application requirements, a multi-stage fast intra mode decision algorithm is proposed. In the first stage, we choose the optimal mode from intra 4×4 and intra 16×16 by extracting the spatial features of macro-block using two-dimension histogram, in combination with double-threshold algorithm. In the second stage, the nine prediction directions in intra 4×4 mode are divided into two groups and the optimal group is selected by pre-determination algorithm before coding. Experimental results show that the proposed algorithm reduces the coding time effectively with little degradation of image quality.