H.264/AVC是目前已發展完成並且壓縮率最高的視訊編碼標準，它支援Intra16×16、Intra4×4的亮度(Luminance)預測及Intra8×8的彩度(Chrominance) 預測做畫面內預測編碼。H.264/AVC利用相鄰的畫素間的相關性，以減少I Frame的冗餘資料，以達到壓縮目的。
對於所有的候選預測模式(candidate mode)，逐一Rate-Distortion Optimization(RDO)運算會增加龐大計算量。為了要降低畫面內預測編碼的運算複雜度，本論文提出一階小波轉換畫面快速偵測演算法(Fast Intra Prediction with Haar Transform Algorithm)主要是針對Intra4×4紋理較為複雜，而Intra16x16紋理較為平坦的特性，利用一階小波轉換後所得的低頻資訊先行區分Macroblock，並針對Intra16x16與Intra4x4先行判斷垂直偵測與水平偵測，藉由減少RDO的候選模式，已達成H.264整體壓縮時間降低的目的。實驗結果顯示，本論文所提出的演算法，可以有效地降低運算複雜度而讓整體壓縮時間降低，且能維持與H.264 Full Search相似的預測結果。

H.264/AVC is well-known for its performance on coding efficiency. It has
advantages of low bit-rate and high image quality. However, the complexity of
H.264/AVC encoder limits applications in the real time video communication. In this
study, a fast intra prediction with Haar transform algorithm (FIPHTA) is proposed to
simplify the complexity of luma intra prediction. For each luma macroblock (MB), a Haar
transform is first executed. By observing LL coefficients, this MB will be classified as
I16-MB, I4-MB, or both. An I16-MB indicates that this MB is smooth and only Intra
16×16 (I16) prediction modes are to be considered. An I4-MB indicates that this MB is
textured and only Intra 4×4 (I4) prediction modes are to be considered. And the rest of
MBs (both) have to consider both prediction modes as in the standard H.264/AVC. Next,
to choose an I16 prediction mode for a MB, the vertical and horizontal energies of the LL
coefficients are calculated to reduce candidate modes. Similarly, the pixel-based vertical
and horizontal energies are calculated for a 4x4 block to reduce I4 candidate modes. The
simulation showed that the proposed algorithm can maintain the similar mode selection
results comparing to the full search algorithm of H.264 but with a remarkable computation
deduction.

目錄

中文摘要.....................................................................................I
英文摘要.....................................................................................II
目錄.....................................................................................III
圖目錄.....................................................................................V
表目錄.....................................................................................VII
第一章 緒論.....................................................................................1
1.1.前言.....................................................................................1
1.2.研究動機...........................................................................2
1.3.論文架構.................................................................3
第二章 H.264/AVC視訊壓縮標準.................................................................5
2.1. H.264壓縮標準流程簡介.........................................6
2.2. H.264/AVC視訊編碼層階層架構................................11
2.3. H.264畫面內預測(Intra Prediction)................................................................14
2.3.1 Intra 4x4................................................................17
2.3.2 Intra 16x16..............................................................21
2.3.3 Chroma 8x8................................................................21
2.4. Related Work...............................................................22
第三章 一階小波轉換快速畫面偵測演算法.................................................................25
3.1. LL-Coefficients Standard Deviation (LL-SD) Algorithm.........................28
3.2. Intra_16x16 LL-Based快速模式決策演算法................................33
3.3. Intra_4x4 Pixel-Based快速模式決策演算法................................37
第四章 實驗數據與模擬結果................................42
4.1. 環境參數與視訊樣本................................42
4.2. 實驗結果................................44
4.2.1 TH4和TH16效能評估................................45
4.2.2 Intra_16x16 LL-Based快速模式決策演算法效能評估................................50
4.2.3 Intra_4x4 Pixel-Based快速模式決策演算法效能評估................................55
4.3. 比較結果................................62
第五章 結論與未來展望................................65
5.1 結論................................65
5.2 未來展望................................66
參考文獻................................67
附錄.................................68

圖目錄

圖2.0.1 視訊編碼壓縮時間演進………………………………………..6
圖2.1.1 Scope of H.264 video coding standard………………………….7
圖2.1.2 H.264編碼區塊圖………………………………………………8
圖2.1.3 H.264解碼區塊圖………………………………………………8
圖2.1.1 H.264 Standard Profile…………………………………………10
圖2.2.1 YCbCr取樣模式………………………………………………12
圖2.2.2 Macroblock partitions for motion estimation and compensation………………………………………………….14
圖2.3.1 空間關聯性示意圖……………………………………………15
圖2.3.2 H.264 Intra Prediction………………………………………….15
圖2.3.3 預測區塊標示圖………………………………………………17
圖2.3.4 Intra4x4方向示意圖…………………………………………..17
圖2.3.5 Luma 4x4 Intra Prediction……………………………………..20
圖2.3.6 Luma 16x16 Intra Prediction…………………………………..21
圖3.1.1 Haar Transform………………………………………………...29
圖3.1.2 LL-Coefficients Standard Deviation (LL-SD) histogram……………………………………………………...30


圖3.1.3 Fast Intra Prediction with Haar Transform(FIPHT)流程圖……………………………………………………………...33
圖3.2.1 Intra_16x16 LL-Base Fast Mode Decision (LL-based I16) Algorithm………………………………………………..……35
圖3.2.2 編緣區塊示意圖………………………………………………36
圖3.3.1 Intra_4x4 Pixel-Based Fast Mode Decision (Pixel-based I4 ) Algorithm………………………………………………..……39
圖3.3.2 Intra4x4 mode prediction direction…………………………….40
圖3.3.3 The complete FIPHTA flow diagram………………………….41
圖4.1.1 測試影像………………………………………………………44

表目錄

表3.0.1 Fast CrIntra Decision比較表…………………………………..26
表3.1.1 LL-SD門檻對照表..…………………………………………...32
表4.1.1實驗環境……………………………………………………….42
表4.2.1 QP=20,HT-SDE測試數據…………………………………….46
表4.2.2 QP=28,HT-SDE測試數據…………………………………….47
表4.2.3 QP=36,HT-SDE測試數據…………………………………….47
表4.2.4 QP=42,HT-SDE測試數據…………………………………….48
表4.2.5 QP=48,HT-SDE測試數據…………………………………….48
表4.2.6 QP=20,Intra16x16 LL-Base測試數據………………………..51
表4.2.7 QP=28,Intra16x16 LL-Base測試數據………………………..52
表4.2.8 QP=36,Intra16x16 LL-Base測試數據………………………..53
表4.2.9 QP=42,Intra16x16 LL-Base測試數據………………………..54
表4.2.10 QP=48,Intra16x16 LL-Base測試數據………………………55
表4.2.11 QP=20,Intra4x4 Pixel-Base測試數據……………………….57
表4.2.12 QP=28,Intra4x4 Pixel-Base測試數據……………………….58
表4.2.13 QP=36,Intra4x4 Pixel-Base測試數據……………………….59
表4.2.14 QP=42,Intra4x4 Pixel-Base測試數據……………………….60
表4.2.15 QP=48,Intra4x4 Pixel-Base測試數據……………………….61
表4.3.1 The average number of RDO computation for one MB under different QP and videos……………………………………….62
表4.3.2 Precision rate (Comparing to the results of the full search of the H.264)…………………………………………………………63

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