在H.264中在壓縮率和影像品質都明顯優於以往的視訊標準。這是因為其使用了新的技術：整數轉換（integer transform）、多幅參考畫面的移動估計（multi-reference frame motion estimation）、可變區塊大小的移動估計（variable block size motion estimation）等等。為了有更好的編碼效益，H.264/AVC 更使用位元率失真函數(rate distortion optimization, RDO）技術來得到更好的編碼效率，但卻會使編碼端的運算複雜度大幅提升，導致增加了硬體實現的困難度；而其計算的複雜度主要分佈在可變區塊大小及多幅參考畫面的移動估計。在本論文探討的是，利用時間域的移動緩慢及移動快速的特性，我們提出加速快速區塊模式決策的方式，在影像品質幾乎沒有失真的情況下，來降低編碼端的運算複雜度來減少運算時間。 Base on some new coding technology as variable block size、multi-frame reference in inter-frame mode coding, H.264/AVC gain more coding efficiency than H.263、MPEG2 and other video sequence standard. However, these feature causes extremely high computational complexity and more coding time when rate distortion optimization (RDO) algorithm had been used in H.264/AVC. This thesis proposed two fast inter-mode decision algorithms to decide the best mode in stationary and non-stationary frame, and that makes use of the spatial homogenous and the temporal stationary. Based on homogeneity and stationary characters of the video objects, only a small number of inter-modes are selected in RDO process. The experimental results show that the fast inter-mode decision is able to reduce the computational complexity and encoding time, and keep most likely video quality with original H.264/AVC coding.
