臺灣博碩士論文加值系統

H.264/AVC可調式視訊編碼(scalable video coding, SVC)使用基礎層與增強層之多層架構來達到空間、時間及品質可調性，但同時也增加了大量的計算量。為了加速空間可調式之視訊編碼，本論文提出了以優先權為基礎的快速模式決策及以動量為基礎的移動估計。在我們所提出的快速模式決策演算法中，使用基礎層中可變大小區塊於模式決策的位元率-失真值來決定增強層中的模式優先順序。在以動量為基礎的移動估計上，我們使用了基礎層上移動向量資訊來減少在增強層搜尋範圍的大小。我們的演算法可以有效地減少增強層的運算複雜度。根據基礎層的位元率-失真值我們也提出計算可調式(Computation Scalability)之演算法，隨著計算量之增加可以達到更好的視訊品質。在實驗結果方面，我們與JSVM比較其數據，在時間上節省了72% 到 81%，而平均的PSNR些微減少了0.05dB，其平均資料量只增加1.9%。

In H.264/AVC scalable video coding (SVC), the multi-layer motion estimation between different layers achieves spatial scalability but accompanies with high coding complexity. To accelerate the encoding time in SVC, a priority-based mode decision and an activity-based motion estimation are proposed in this thesis. In the proposed mode decision, the rate-distortion costs of the base layer are used to decide the priority of the mode in enhancement layer. The activity-based motion estimation employs motion vector difference in base layer to decrease search range. We also propose a computation-scalable algorithm to provide the quality scalability according to the allocated computation power. Through the proposed algorithms, the computation complexity come from the enhancement layer could be efficiently reduced. Compared with JSVM, the experimental results demonstrate that 72% to 81% time saving is achieved with negligible 0.05 PSNR decrease and only 1.9% bitrate increase.

摘要 i
ABSTRACT ii
目錄 iii
圖索引 vi
表索引 xi
第一章 簡介 1
1.1 視訊編碼概述 1
1.2 可調式視訊編碼概要 9
1.3 研究動機 17
1.4 論文架構 18
第二章 可調式視訊編碼之模式快策與移動估計 19
2.1 移動估計 19
2.1.1 多重參考畫面 21
2.1.2 可變區塊大小及模式決策 22
2.1.3 1/4精確度的移動估計 23
2.2可調式視訊編碼之模式決策的先前研究 25
第三章 所提出的模式決策與移動估計演算法 31
3.1 觀察階層間的相關性及移動向量差 31
3.1.1 階層間的相關性 32
3.1.2 移動向量差值 34
3.2 以優先權為基礎的模式決策(Priority-Based Mode Decision, PBMD) 39
3.3 以動量為基礎的移動估計決策(Activity-Based Motion Estimation, ABME) 41
3.4 計算可調式之模式決策演算法(Computation Scalability) 44
第四章 實驗結果 45
4.1 實驗環境與參數 46
4.2 實驗比較 48
4.2.1 實驗數據與結果 48
4.2.2 PBMD & ABME 比較 52
4.2.3 與其它方法之比較 56
4.2.4 應用於計算量可調的方法 62
第五章 結論與未來展望 71
參考文獻 73

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