H.264中基于特征的快速帧内4×4模式选择算法

Fast Feature-based 4×4 Intra Mode Decision Algorithm in H.264

提出了一种快速帧内4×4模式选择算法。该方法利用最可能的模式（MPM）、前帧同位置块编码模式（PBM）及绝对变换差和（SATD）等特征，定义了一种代价函数FMPS。基于该代价函数算法再通过设置阈值排除了大部分的候选模式，最终仅计算1-3种模式的率失真代价。实验结果也表明，相比于标准算法，提出的方法在基本不改变编码效率的情况下，节省了约75％的编码时间。因此，本算法非常适用于低复杂度的编码系统。

To reduce the computational complexity, a fast intra 4×4 mode decision algorithm is proposed. By using the basic features of Most Probable Mode （MPM）, Previous Co-block Mode （PBM） and the sum of Absolute Transformed Difference （SATD） between the original block and the predicted block, a cost function FMPS is defined. Then several thresholds are given to reduce the number of candidate modes to one to three maximum. Experimental results show that the proposed algorithm can reduce about 75% of the total encoding time with little degradation in coding performance compared to the full search algorithm. So the proposed method is very suitable for low complexity coding system.