基于降采样方式的快速帧间模式选择算法

摘要

Aiming at the problem that complexity of H .264 inter frame mode decision algorithm is high ,a fast inter frame mode selection algorithm is proposed in this paper .The algorithm employs down‐sampling method to detect and antici‐pate the SKIP macroblocks ,which can effectively reduce the computation of all‐zero macroblock detection .Meanwhile ,the proposed algorithm applies down‐sampling method to the motion estimation search procedure of macroblaock and its segmen‐tations ,which can greatly reduce the computation of block matching in original algorithm .And also ,the proposed algorithm narrows the range of optimal mode ,according to sub‐macroblock motion homogeneity .When compared with the x264 inter frame mode selection algorithm using UM HexagonS ,the proposed algorithm reduces about 40% encoding time on average , while keeping the original stream bit rate and the peak signal to noise ratio substantially unchanged ,and significantly im‐proves the coding efficiency .%针对 H ．264中帧间模式选择算法复杂度过高的问题，论文提出一种快速帧间模式选择算法。算法采用降采样方式对 SKIP 宏块进行检测与预判，有效降低宏块全零检测的计算量；改进 UM HexagonS 算法，对宏块与宏块分割使用降采样的方式进行运动搜索，大大减少原算法中块匹配的计算量；根据子宏块运动同质性来缩小最优模式的选择区间。与采用 UM HexagonS 的 x264帧间模式选择算法比较，所提的算法在维持原有码率与峰值信噪比基本不变的情况下，使编码时间平均减少40％，显著提高了编码效率。