提出一种基于感知的快速自适应环路滤波算法,利用最小可察觉失真模型和Canny算子将最大编码单元进行分类,对不同分类区域进行自适应环路滤波(adaptive loop filter,ALF)的性能评估和分析,在此基础上跳过所有非敏感平滑区域和敏感平滑区域耗时的ALF处理.实验结果表明,该算法能在视频主观质量和客观质量基本不变的前提下大大降低ALF编码复杂度,有效改善ALF性能.与现有高效ALF算法相比,该算法可在编码复杂度相当的情况下获得更好的主观视频质量.
This work proposes a perceptually fast adaptive loop filter algorithm to reduce coding complexity. The largest coding units (LCUs) are classified into different regions according to the just noticeable distortion (JND) profile and using a Canny operator. Based on the ALF performance assessment and an analysis of different regions, all ALF processes for LCUs in sensitive smooth regions and non-sensitive smooth regions are skipped. Experimental results show that the proposed method can significantly reduce ALF encoding complexity while maintaining video quality. The proposed algorithm can achieve better subjective video quality with similar coding complexity compared with the existing efficient ALF algorithm.
[1] Sullivan G J, Ohm J R, Han W J. Overview of the high efficiency video coding (HEVC) standard[J]. IEEE Transactions on Circuits and Systems for Video Technology, 2012, 22(12):1649-1668.
[2] Doc. JCT3V-C1001. 3D-AVC draft text 5[S]. Geneva, Jan.2013.
[3] Joint Collaborative Team on 3D Video (JCT-3V).[Online]. Available:https://hevc.hhi.fraunhofer.de/svn/svn_3DVCSoftware/tags/HTM-9.2/.
[4] Tsai C Y, Chen C Y, Yamakage T. Adaptive loop filtering for video coding[J]. IEEE Journal of Selected Topics in Signal Processing, 2013, 7(6):934-945.
[5] Doc.JCTVC-F028. CE8:summary report of non-deblocking loop filtering[S]. Torino, Mar. 2011.
[6] Doc.JCTVC-G1023. CE8 Subset 0:improved ALF N pass encoding[S]. Geneva, Nov. 2011.
[7] Doc.JCTVC-F301. CE8 Subset 1:block-based filter adaptation with features on subtest of pixels[S]. Torino, Jul. 2011.
[8] Doc.JCTVC-F303. CE8 subset 4:ALF using vertical-size 5 filters with up to 9 coefficients[S]. Torino, Jul. 2011.
[9] Budagavi M, Size V, Zhou M. HEVC ALF decode complexity analysis and reduction[C]//IEEE International Conference on Image Processing (ICIP), Brussels, 2011:733-736.
[10] Miyazawa K, Murakami T, Minezawa A. Complexity reduction of in-loop filtering for compressed image restoration in HEVC[C]//Picture Coding Symposium (PCS), Krakow, 2012:413-416.
[11] Zhang Y F, Tang Y Z, Li B. Spatial correlation and texture-based fast adaptive loop filter for HEVC[C]//International Conference on Wireless Communications & Signal Processing (WCSP), Huangshan, 2012:25-27.
[12] Park S, Choi K, Noh G. Frame-based adaptive selection of ALF for fast HEVC decoding[C]//IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB), 2012:1-4.
[13] 蒋刚毅,朱亚培,郁梅. 基于感知的视频编码方法综述[J]. 电子与信息学报,2013, 35(2):474-483. Jiang G Y, Zhu Y P, Yu M. Perceptual video coding:a survey[J]. Journal of Electronics & Information Technology, 2013, 35(2):474-483.(in Chinese)
[14] Yang X, Lin W, Lu Z. Motion-compensated residue preprocessing in video coding based on just-noticeable-distortion profile[J]. IEEE Transactions on Circuits and Systems for Video Technology, 2005, 15(6):742-752.
[15] Doc. ITU-T-SG16-C181. Quadtree-based adaptive loop filter[S]. Geneva, Jan. 2009.
[16] Doc.JCTVC-H1003. High efficiency video coding (HEVC) text specification draft 6[S]. San Jose, Feb. 2012.
[17] 罗丽冬,王永芳,商习武,杨萍,张兆扬. 一种基于多视点视频的低复杂度自适应环路滤波算法[J]. 光电子·激光,2014, 25(2):336-342. Luo L D, Wang Y F, Shang X W, Yang P, Zhang Z Y. A low complexity adaptive loop filter algorithm for multi-view video coding[J]. Journal of Optoelectronics Laser, 2014, 25(2):336-342. (in Chinese)
[18] Doc.VCEG-M33. Calculation of average PSNR differences between RD-curves[S]. Porto Seguro, Apr. 2001.
[19] Conceicao R, Rediess F, Zatt B, Porto M, Agostini L. Configurable hardware design for the HEVC-based adaptive loop filter[C]//2014 IEEE 5th Latin American Symposium on Circuits and Systems (LASCAS), 2014:1-4.
[20] Han Q L, Cham W K. Temporal layer adaptive loop filter for HEVC[C]//2014 IEEE International Conference on Image Processing (ICIP), 2014:3758-3762.
