A Low Complexity Fast Intra Mode Decision Algorithm for H.264/AVC

H.264/AVC intra prediction employs the rate distortion optimization (RDO) technique to get to the best encoding performance. But exhaustively searching all candidate modes dramatically increases the computational complexity for encoding. In order to reduce the computational complexity, in this work, we proposed a low complexity mode decision algorithm which is based on reducing the number of candidate modes for further RDO calculation. The proposed algorithm can decide the interpolation direction accurately by calculating the directional pixel-value differences (DPD) of target block and then do statistic with the obtained values to choose the most probable modes. Experimental results demonstrate that the proposed algorithm can achieve more than 70% time saving than H.264 referenced software with tiny degradation of encoding performance.