臺灣博碩士論文加值系統

新一代高效率視訊編碼 (HEVC) ，是以H.264/AVC編碼技術為核心並且加以改進，將壓縮效率提高一倍，在相近的重建視訊畫面品質，約節省50% 的位元率，但也同時提高了編碼複雜度，增加了編碼時間。
本論文提出一種快速編碼單元分割演算法及畫面內預測之快速模式決策的方法，利用當前編碼樹單元 (CTU) 相鄰五個編碼單元 (CU) 之深度加權平均值，預估當前編碼樹單元的深度範圍，跳過較小深度的編碼單元分割之判斷或省略較大深度的編碼單元分割，以加速編碼單元分割，以及減少畫面內預測之候選列表的模式數量，降低計算複雜度以節省更多編碼時間。從實驗結果顯示，與HEVC參考軟體HM16.20相比，我們所提出的方法，平均可以節省47.696 %的編碼時間，且平均位元率 BD-BR 僅增加3.122 %，而平均重建視訊畫面品質BD-PSNR僅減少0.163 dB。

The high efficiency video coding (HEVC), the recent generation of video coding standard, is based on H.264/AVC coding technology. It improves the compression efficiency to save about 50% of the bit rate while preserving the similar quality of reconstructed video, but it also increases the computational complexity and results in the requirement of more encoding time.
This paper proposes a fast coding unit partition and a fast mode decision algorithm for HEVC intra-frame prediction. The weighted average of the depths of five adjacent coding units (CU) of the size 3232 is utilized to predict the depth of current coding tree unit (CTU). Skipping the judgment of smaller-depth coding unit partition or omitting the larger-depth coding unit partition speeds up the coding unit partition. And, the number of modes in the candidate list of intra-frame prediction in the rough mode decision phase is reduced to lower the computational complexity and save the encoding time more. The experimental results show that compared with the algorithm of HEVC reference software HM16.20, our proposed method can save 47.696% of the coding time on average, and the average bit rate of BD-BR increases by only 3.122%, while the average quality of reconstructed video of BD-PSNR is only reduced by 0.163dB.

目錄


摘要 .................................. i
ABSTRACT .............................. ii
誌謝 .................................. iv
目錄 .................................. v
英文簡寫說明 .......................... vi
中英文對照表 .......................... ix
圖目錄 ................................ xiii
表目錄 ................................ xv
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視訊編碼概述 .................. 4
2.2 HEVC視訊編碼架構 .................. 4
2.3 四分樹分割 (Quad-tree Structure) .. 5
2.3.1 編碼單元(Coding Unit, CU) ....... 8
2.3.2 預測單元(Prediction Unit, PU) ... 10
2.3.3 轉換單元(Transform Unit, TU) .... 13
2.3.4 階層編碼結構 .................... 13
第三章、 我們提出的方法 ............... 19
3.1 基本介紹 .......................... 19
3.2 我們改進Liao等[4]的畫面內預測之快速模式決策 ....................................... 19
3.3 Lu等[5]的編碼單元快速分割方法 ..................................................... 23
3.4 我們改進Liao等[4]的畫面內預測之快速模式決策並結合Lu等[5]的編碼單元快速分割方法 .... 26
第四章、 實驗結果 ..................... 29
4.1 緒論............................... 29
4.2 實驗環境 .......................... 29
4.3 測試視訊序列 ...................... 29
4.4 實驗結果與效能比較 ................ 40
第五章、 結論.......................... 62
參考文獻 .............................. 64

[ 1 ] T. Wiegand, G. J. Sullivan, G. Bjontegaard, and A. Luthra, “Overview of the H.264/AVC video coding standard,” IEEE Trans. Circuits and Systems for Video Technology, vol. 13, no. 7, pp. 560-576, July 2003.
[ 2 ] G. J. Sullivan, J.-R. Ohm, W.-J. Han, and T. Wiegand, “Overview of the High Efficiency Video Coding (HEVC) standard,” IEEE Transactions Circuits and Systems for Video Technology, vol. 22, no. 12, pp. 1649-1668, Dec. 2012.
[ 3 ] I. K. Kim, K. McCann, K. Sugimoto, B. Bross, G. J. Sullivan, and W. J. Han, “High Efficiency Video Coding (HEVC) Test Model 10 (HM10) encoder description,” JCTVC-L1002_v3, Geneva, CH, Jan. 2013.
[ 4 ] W. Liao, D. Yang, and Z. Chen, “A fast mode decision algorithm for HEVC intra prediction,” in 2016 Visual Communications and Image Processing (VCIP), 2016, pp. 1-4.
[ 5 ] J. Lu and Y. Li, “Fast algorithm for CU partitioning and mode selection in HEVC intra prediction, ” in 2019 12th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics (CISP-BMEI), 2019, pp. 1-5.
[ 6 ] S. Pateux and J. Jung, “An excel add-in for computing Bjontegaard metric and its evolution,” ITU-T Q/6SG16, Doc. VCEG-AE07, in 33th Meeting, Marrakech, Morocco, Jan. 2007.