摘要： H.264是目前最新的视频编码标准。同以往标准相比，一个明显的改进就是使用了多种宏块分块模式从而使运动估计更为精确。但是计算量非常惊人。虽然JVT采用了一个快速运动估计(FME)的提案能在码率和效果基本无变化的情况下极大地提高搜索速度，但计算量仍很大。该文提出了一个对基于分裂与合并的宏块模式快速选择算法，在8×8块搜索基础上先由运动向量剧烈程度决定合并或分裂，而对中间的运动向量推导出一个阈值来决定是否合并。实验证明该算法能在码率和效果基本不受影响的情况下极大地提高编码的速度。

关键词: H.264, 宏块模式, 分裂, 合并

Abstract: H.264 is the latest under development video coding standard. It uses variable-size block to improve the motion estimation accuracy of inter-coding blocks. But it is extremely computational intensive. Though JVT adopts a proposal about fast motion estimation(FME) which shows very good capability in keeping the rate distortion performance and a great computation reduction can be achieved, still computes complex. This paper proposes and investigates fast variable block-size motion estimation algorithms based on merge and split procedures for H.264 video encoding. Experiments results show that the proposed method can save about 24.7% to 29.7% computations while keeping similar picture quality.

Key words: H.264, Variable-size block, Merge, Split