H.264/AVC為目前主要流通的視訊壓縮編碼標準之一，然而隨著我們對於視訊品質的要求越來越高，舊的壓縮標準已不敷使用，所以在西元2013年4月的時候，JCT-VC推出了新一代視訊壓縮編碼標準HEVC，在未來HEVC將會逐漸廣泛應用於各項產品之中，因此該如何有效率地將H.264/AVC轉換編碼至HEVC便成為一項重要的課題。
本論文提出一套H.264/AVC至HEVC快速轉換編碼演算法，重複利用H.264/AVC解碼之特徵資訊如運動向量、預測模式、預測殘餘值等做為演算法判斷準則，分別對預測單位模式提出快速決策方法，以及針對移動估測提出快速搜尋方法，達到加速轉換編碼之效果，實驗結果顯示最多可節省至53%的運算複雜度，約可省去一半以上的編碼時間並維持良好視訊壓縮效率，因此本論文所提出之演算法在編碼時間節省上具有相當優勢。

H.264/AVC is one of the most commonly applied video compression standards. However, with the increasing demands on high quality video applications, previous standards are not efficient enough to support the new requirements. Thus, a new video compression standard, High Efficient Video Coding (HEVC), had been developed and finalized by JCT-VC in April 2013. With the high coding efficiency, it can be expected that HEVC will be widely adopted for many applications in the future. Therefore, it becomes an important issue to efficiently transcode H.264/AVC to HEVC.
In this thesis, we propose a fast transcoding algorithm for H.264/AVC to HEVC. The proposed algorithm reuses coding information from H.264/AVC decoder such as motion vectors, coding modes, and residual values to speed up the prediction process for the HEVC encoder. The proposed algorithm is composed of two parts to speed up the transcoding process. One is fast algorithm for the prediction unit (PU) mode decision, and the other is the adaptive search range selection to save time for the motion estimation. Experimental results show that computational complexity can be saved up to 53%. That is, more than half of the encoding time is reduced under good rate-distortion (R-D) performance.

摘要 i
Abstract ii
致謝 iii
目錄 iv
圖目錄 vii
表目錄 x
第一章 緒論 1
1.1 研究背景 1
1.2 研究動機與目的 2
1.3 論文架構 3
第二章 HEVC視訊編碼標準介紹 4
2.1 HEVC視訊編碼介紹 4
2.2 HEVC視訊編碼基本單位 6
2.2.1 編碼單位（Coding Unit） 7
2.2.2 預測單位（Prediction Unit） 8
2.2.3 轉換單位（Transform Unit） 10
2.3 HEVC視訊編碼技術 11
2.3.1 畫面內預測（Intra Prediction） 12
2.3.2 畫面間預測（Inter Prediction） 14
2.3.3 轉換及量化（Transform and Quantization） 20
2.3.4 熵編碼（Entropy Coding） 21
2.3.5 迴路濾波器（Loop Filter） 22
第三章 視訊轉換編碼介紹 25
3.1 視訊轉換編碼系統 25
3.1.1 視訊轉換編碼器介紹 26
3.1.2 像素域轉換編碼器 27
3.1.3 轉換域轉換編碼器 28
3.2 H.264/AVC至HEVC轉碼相關文獻探討 29
第四章 預測單位之快速轉換編碼演算法 35
4.1 H.264/AVC解碼器之特徵資訊擷取 35
4.2 HEVC模式決策及移動搜尋介紹 38
4.3 當編碼單位對應數個巨區塊之演算法 41
4.3.1 預測單位模式快速決策演算法 42
4.3.2 移動估測快速搜尋演算法 54
4.4 當編碼單位對應唯一巨區塊之演算法 58
4.4.1 預測單位模式快速決策演算法 59
4.4.2 移動估測快速搜尋演算法 69
4.5 快速轉換編碼演算法之流程 70
第五章 實驗結果及討論 76
5.1 實驗參數環境設定 76
5.1.1 測試視訊序列 76
5.1.2 實驗環境 77
5.2 實驗結果 78
5.2.1 快速模式決策演算法效能分析 78
5.2.2 快速移動估測演算法效能分析 79
5.2.3 整體演算法效能分析 80
第六章 結論與未來展望 82
參考文獻 83

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