H.264之快速小數點移動估測法則之研究

Fast Fractional Pixel Search Algorithm in H.264/AVC

王穎智(Ying-Chih Wang)

指導教授 ： 林銀議

國立中央大學/資訊電機學院/通訊工程學系/碩士(2007年)

摘要

H.264是現今最新的視訊壓縮技術，其四分之ㄧ精確度(quarter resolution)的移動補償(motion compensation)可使系統對物體移動的描述更為精準。然而當解析度越高時，系統所要花費在移動估算(motion estimation)的的時間也越多，複雜度也相對提升，所以減少搜尋點數(searching points)是必然且有意義的。我們利用[7]所提出的以拋物曲面為預測函數(paraboloid prediction convex function)，並改善其搜尋點數的條件來達到複雜度的減低。使原本在半像素解析度上，搜尋點數從9點減少至2點，運算複雜度降低大約78%；在四分之ㄧ精確點解析度上，搜尋點數從17點減少至大約6點，運算複雜度降低大約65%。實驗結果中可證明不管是哪種解析度，我們都能維持一定的編碼效能。

關鍵字

H.264 ； 移動估測 ； 四分之ㄧ精確點 ； 對稱曲面函數

並列摘要

H.264/AVC is a new video compression coding standard, in which quarter resolution and motion compensation can achieve more accurate motion description. It means that we need more time to find the best condition. Therefore, reducing the computational complexity for fractional pixels is necessary and significant. We proposed a fast fractional pixel search algorithm using symmetric convex cup for half and quarter resolution. In any case (half and quarter resolution), we can roughly reduce 65%~78% of computation complexity compared to that in the reference software. Experimental results show that our proposed algorithm preserve almost the same rate-distortion curve , which compare to the original full search(FS).

並列關鍵字

half pixel ； quarter pixel ； H.264 ； symmetric convex cup

參考文獻

【1】Zhibo Chen, Peng Zhou, and Yun He, “Fast Integer Pel and Fractional Pel Motion Estimation for JVT,” JVT-F017, 6th Meeting, Awaji, Japan, Dec. 5 –13, 2002.

【5】Hoi-Ming Wong, Oscar C. Au, Andy Chang, “Fast sub-pixel inter-prediction - based on texture direction analysis (FSIP-BTDA)” Proceeding of IEEE International Symposium on Circuits and Systems(ISCAS), vol. 6, pp.5477-5480, May 2005.

【6】Yilong Liu, and Soontorn Oraintara, “Fractional-pel motion refinement based on hierarchical adjustable dual-parabola model,” Proceeding of IEEE International Symposium on Communications and Information Technology (ISCIT), vol. 2, pp.752-755, Oct. 2004.

【7】 Cheng Du, Yun He, and Junli Zheng, “PPHPS: a parabolic prediction-based, fast half-pixel search algorithm for very low bit-rate moving-picture coding,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, pp.514-518, June 2003.

【8】Zhibo Chen, Cheng Du, and Jinghua Wang, and Yun He, “PPFPS - a paraboloid prediction based fractional pixel search strategy for H.26L,” Proceeding of IEEE International Symposium on Circuits and Systems (ISCAS), vol. 3, pp. III-9- III-12, 2002.