在H.264/AVC的畫面間編碼(inter-coding)預測之中，多重區塊大小的選擇是一項重要的技術。標準中所制定的七種區塊大小將一個巨區塊(macroblock, MB)切割成幾個部份。當不同的物件包含在同一個巨區塊的時候，較小的區塊比較能夠達到更好的動態預測結果。然而，當所有的區塊大小都被選取為決定最佳區塊大小的判定時，這項技術將會造成巨大的運算量。本篇論文提出一個快速的Inter模式決策演算法來減少所需考慮的模式數量，使得運算時間也能夠同時下降。我們使用在前一張畫面同位置的巨區塊以及它的鄰居作為判斷的候選者。接著指定每種模式一個各別的分數來檢查是否有一條移動物件的邊緣經過這些候選者。實驗結果顯示我們的快速模式決策演算法可以在平均降低0.05dB的PSNR以及2%的位元率增加之下達到降低31%-41%的整體編碼時間以及41%-54%的動態預估時間。

Variable block size used for inter coding is one of the key technologies in H.264/AVC. These seven block sizes partition a macroblock into several parts. When different objects contained in the same macroblock have different motions, smaller block sizes probably achieve better predictions. However, this feature results in extremely high computational complexity when all the block sizes are considered to decide a best one. This paper proposes a fast inter mode decision algorithm to reduce the numbers of inter mode that has to be checked, and the time is also reduced. We use the co-located macroblock in previous frame and its neighbors as candidates. And check whether an edge of moving object is crossing the middle of these candidates by using the score given to the modes. The experimental results show that the fast inter mode decision algorithm is able to reduce 31%-41% total encoding time and about 41%-54% motion estimation time with a negligible PSNR loss of 0.05 dB and bit-rate increment of 2% on the average.

AbstractOutlineList of Figures List of Tables Chapter 1 INTRODUCTION 1.1 Overview of The Video Coding Layer 1.2 Main Innovative Features in H.264/AVC 1.2.1 Variable Blocks Size Motion Estimation (VBSME) 1.2.2 Multiple Reference Frame 1.2.3 Intra Prediction 1.3 Motivation Chapter 2 Mode Decision in H.264 and Related Works 1.1 VBSME 1.1.1 SAD and PDE 1.1.2 Spiral Search Order and MVP 1.1.3 Cost Calculation in H.264 1.2 RDO 1.3 Related Works Chapter 3 Proposed Method Chapter 4 Experimental Results Chapter 5 Future Work and Conclusion 1.4 Conclusion 1.5 Future Work REFERENCES

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