新一代的視訊編碼技術HEVC (高效率視訊編碼技術)比現行的標準
H.264/MPEG-4 AVC,HEVC具有更佳的解析度視訊畫面以及有夠優的壓縮效果。 然而,這些優點也代表需要更高的計算量及更好的設備。
為了解決這個問題,這篇論文主要研究HEVC在異質系統中發揮更高效能,分 析HEVC中的各個工作流程,將最花時間計算效能的部分進行時間最佳化,針對動 態估計部分以及選擇CTU的切法加以改良,用邊緣偵測的方式加速HEVC,取代原 本藉由計算找出最佳切法方式,以邊緣偵測後的數值直接決定好CTU的切法。
實驗結果可得知比起原先的x265技術,在QP為22時速度平均提升7.78倍,PSNR 失真率平均在-1.79%,Bit-rate則平均提升了6.57%,若跟無邊緣偵測跑在GPU版本 相比下,QP為22時速度提升了4.34倍。

HEVC is the latest video compression standard, which provides better compression ration and video quality than H.264. However, its computational time is much higher than previous standards. One of the performance bottleneck is mode decision, which searches the best mode for motion estimation. In this thesis, we proposed a method to accelerate the mode decision and motion estimation on the CTU level. The method uses edge detection to estimate the proper mode of each CTU blocks, instead of searching the best mode from bottom to top. The method has been implemented on GPU and CPU. Experiments show that comparing with the x265 and previous work, the performance can be improved up to eight times with slightly increases in bitrate and PSNR.

Chinese Abstract i
Abstract ii Contents iv
List of Figures vi
List of Tables vii 1 Introduction 1
2 Background 4
2.1 MotionEstimation ............................ 4 2.2 MVPandAMVP............................. 5 2.3 SearchMethod .............................. 6 2.4 CodingTreeUnit............................. 7 2.5 ModeDecision............................... 8 2.6 RelatedWork ............................... 10
3 Methodology 12
3.1 Proposedmethod............................. 12 3.2 GPUAlgorithmwithoutEdgeDetectionMethod . . . . . . . . . . . 13 3.3 SobelOperator .............................. 14 3.4 EdgeModeDecision ........................... 15 3.5 DecidetheMode ............................. 16
4 Experiments 19
4.1 ExperimentalEnvironment........................ 19
iv
4.2 Comparisonwithx265CPUmethod .................. 19 4.3 Comparewiththemethodwithoutedgedetection . . . . . . . . . . . 21
5 Conclusion
23

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