H.264编码算法研究与编优化.docx

对整个H．264编码器的程序结构和数据结构进行适当的优化，本文依 据这一思路对H．264编码器中所使用的部分关键算法进行了比较。 把上述有关算法综合运用到H．264编码器中，在参考软件JM8．6 框架下对程序与数据结构进行了适当优化，并对～些关键模块如整像 素运动估计中求残差的绝对误差和SAD，分数像素运动估计中求残差 的Hadamard变换及对变换后的残差矩阵求取绝对值和SATD，整数变 换及其逆变换，亚像素内插等模块利用PC机的多媒体指令系统进行指 令级优化，取得了比较满意的加速效果。 关键词：H．264，实时编码，视频编码标准，运动估计，指令优化 Ⅱ  ABSTRACT H．264 is the newest international video coding standard proposed by the Joint Video Team of ITU—T VCEG and ISO／IEC MPEG． H．264 also uses hybrid video coding scheme based on mot ion compensat ion and transform．In order to avoid the matching error in IDCT caused by DCT in prior video standards，H．264 ut i l izes a new approx imate DCT transform--integer transform．H．264 uses intra prediction to promote the intra encoding efficiency．It adopts variable block sizes，high exact fractional mot ion estimation and compensation and multi—’reference frame selection to describe exactly the actual mot ion vector of objects．In order to el iminate the marginal effect，H．264 uses adaptive in—loop deblocking fi lter．H．264 uses CABAC to decrease the bits needed for encod i ng and SO on．H．264 can decrease about 50％perc ent of bit rates with the same reconstructed picture quality comparing with prior standards by using above advance in video coding technology．But the high efficiency leads to high complexity of implementation directly．‘The various video coding standard Simulation comparison show that H．264 obtain a higher qual ity than any other video coding standard，but encode speed slower than other video standard，this will limit the application of H．264 in real t ime video coding．So it is important to implement the U．264 coder with low hardware complexity and high encoding efficiency． In order to achieve high encoding efficiency，a．264 uses a great deal of encoding algorithms with high complexity．These complexity algorithms will limit the application of H．264 in real time video coding．So we must find corresponding fast algorithms nI  to replace those with high complexity in H．264 reference softwar