Hierarchical Mode and Reference Frame Pre-Decision for H.264/AVC Encoder

H.264/AVC is the most popular standard currently which used for video codec to achieve high quality video communication. However, it is hard for the mobile devices which have limited power supply and processing ability to implement realtime video communication with H.264/AVC due to its huge encoding complexity. To solve this problem, a high quality with low-cost interframe mode decision algorithm is proposed in this paper, which reduces the redundant candidate modes and reference frames for each block type by using coded macroblock (MB) information. Firstly, the best reference frame for each mode is predicted to reduce the original multiple reference frame candidates. And then, a hierarchical mode pre-decision is utilized to reduce the redundant modes. According to the results of our experiments, the proposed algorithm can reduce about 70% encoding time on average with little video quality loss and bitrate increase.