新一代的視訊壓縮標準H.264/AVC可比目前的影像標準獲得更高的壓縮率及影像品質，為了達到這些效能的提升也必須使用龐大的計算量來達到此效果。為了使系統運作更有效率，我們提出了兩種快速畫面內模式決策的方法，一種是利用位元率估測技術取代原先的RD cost函式，讓計算每個所花費的時間降低。另外一種是利用絕對轉換誤差和與差值變異數對於像數值的特徵關係先將可能成為最佳模式的候選模式過濾出來，如此一來就不需每個模式都通過RD cost計算，只須計算我們選出來的幾個候選模式即可。根據實驗結果顯示，我們提出來的兩個快速畫面內模式預測在些微的效能品質降低的情況下可以節省70%~90%的計算量。 H.264/AVC is newest video coding standard and aims to enable significantly improved compression performance compared to all existing video coding. In H.264/AVC, the optimal coding mode decision for each coding block can be achieved by exhaustively calculating the rate-distortion cost. This thesis proposed two fast intra mode decision algorithms to decide the best mode in intra coding. One is rate estimation method for further reduction of RD cost calculation and another is feature-based intra mode prediction with SATD and variance. The experimental results show that both of the fast intra mode decisions are able to reduce the encoding time, with a negligible performance degradation.
