H.264視訊編碼標準提出SP/SI 畫面來達到無損串流切換。然而， SP/SI畫面必須先在原本的串流中設定切換點，因此通常無法達成即時切換的效果。若欲設定多個切換點，整體編碼效率將因而受到影響。本論文提出基於H.264編碼標準之動態串流切換，這個新的編碼機制能夠達成即時無損串流切換,且能夠運用於多位元率串流與多視角串流，達到視訊的調適性和視角的自由選擇性。我們將一張畫面分成移動補償畫面和冗餘畫面，利用SP/SI的概念各自獨立編碼。對於多視角視訊，利用不同視訊畫面間的關係，減少資料大小，利用SIFT演算法來預估整個畫面的位移，並且利用直方圖比對的方法，降低不同視角間的顏色差異，提升編碼效益。實驗結果顯示，我們所提出的方法在動態串流切換有良好的編碼表現結果。 The SP-frame in H.264 facilitates the drift-free bit-stream switching. However, the switching points have to be periodically inserted into the bit-stream in advance and thus the low-delay bit-stream switching may not be achieved. If many switching points are assigned, the coding performance of SP/SI frames will be affected. In this research, we consider the dynamic bit-stream switching in H.264/AVC, which can be applied on both the multi-rate coding and multi-view coding for video adaption and free-viewpoint switching. A novel coding scheme is proposed to enable the drift-free switching at any frame. We separate a frame into two components, i.e. the motion compensated part and residuals, which are encoded independently by employing the concept of SP/SI frames. For interview coding, the inter-correlation from the different views is further utilized. We apply SIFT to estimate the global displacement and the histogram matching algorithm to correct the color inconsistence in different scenes so that the negative effects of secondary SP frames can be reduced. Experimental results show that our scheme has good performance in the free bit-stream switching.
