H.264视频编码的帧内预测算法研究
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摘要
H.264是由ITU-T的视频编码专家组和ISO的运动图象专家组共同制定的新的视频编码标准。H.264标准中包含了很多先进的视频压缩编码方法,与以前的视频编码标准相比具有更好的压缩性能,同时由于其设计的合理性,使得该标准具有良好的网络友好性。然而,高编码压缩率是以高的计算复杂度为代价的,这样很难将H.264标准应用到实时性要求较高的场合,限制了标准的应用范围。为了使H.264能够更好地应用于实时多媒体通信,就必须对其算法进行优化以降低计算复杂度,从而缩短编码时间。本文在详细研究H.264视频编码特点的基础上,深入分析了帧内预测编码,并提出了关于帧内预测编码的改进算法。
H.264中的帧内预测是充分利用视频信号在空间上的相关性进行压缩编码传输的。标准中采用基于率失真优化的全搜索算法进行最佳预测模式的选择,这样计算量巨大。本文首先分析了基于边缘方向直方图的Pan算法,并进行了优化,实验结果表明,改进的算法在保证图象编码质量和码率的同时,大大缩短了编码时间。其次,深入分析了另外两种基于图象纹理特性的帧内预测算法,并针对其不足之处提出了改进算法。实验表明,该算法在保证图象质量的条件下,编码时间进一步缩短,并且易于进行硬件实现。
H.264 is the newest video coding standard of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). H.264 adopted many effective methods to improve compression performance.So it can achieve considerable higher coding efficiency than previous standards.Besides, H.264 processes the provision of“network -friendly”.However, the high complexity comes with the high compression, so it is difficult to implement in real-time applications.Thus, we must optimize the algorithm to reduce the complexity.
The article provides an overview of technical features of H.264, introduce the theory of intra prediction in detail, and advance two novel improved fast algorithms of intra prediction.
Intra prediction of H.264 utilizes the spatial relativity to compress. H.264 adoptes Full Search algorithm based on Rate Distortion Optimization (RDO) to select the best predictive mode.In this way, the computation is drastically increased. The article,firstly, optimize the Pan’s algorithm, and the simulation results show that without considerable performance degradation, the proposed method decreases complexity of the intra-prediction mode decision.Secondly, the paper analyze another two methods of edge detection, and proposed its improvement algorithm. Experimental results show that the proposed algorithm reduces coding time without considerable performance degradation.Besides, it is easily to apply to hardware.
H.264中的帧内预测是充分利用视频信号在空间上的相关性进行压缩编码传输的。标准中采用基于率失真优化的全搜索算法进行最佳预测模式的选择,这样计算量巨大。本文首先分析了基于边缘方向直方图的Pan算法,并进行了优化,实验结果表明,改进的算法在保证图象编码质量和码率的同时,大大缩短了编码时间。其次,深入分析了另外两种基于图象纹理特性的帧内预测算法,并针对其不足之处提出了改进算法。实验表明,该算法在保证图象质量的条件下,编码时间进一步缩短,并且易于进行硬件实现。
H.264 is the newest video coding standard of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). H.264 adopted many effective methods to improve compression performance.So it can achieve considerable higher coding efficiency than previous standards.Besides, H.264 processes the provision of“network -friendly”.However, the high complexity comes with the high compression, so it is difficult to implement in real-time applications.Thus, we must optimize the algorithm to reduce the complexity.
The article provides an overview of technical features of H.264, introduce the theory of intra prediction in detail, and advance two novel improved fast algorithms of intra prediction.
Intra prediction of H.264 utilizes the spatial relativity to compress. H.264 adoptes Full Search algorithm based on Rate Distortion Optimization (RDO) to select the best predictive mode.In this way, the computation is drastically increased. The article,firstly, optimize the Pan’s algorithm, and the simulation results show that without considerable performance degradation, the proposed method decreases complexity of the intra-prediction mode decision.Secondly, the paper analyze another two methods of edge detection, and proposed its improvement algorithm. Experimental results show that the proposed algorithm reduces coding time without considerable performance degradation.Besides, it is easily to apply to hardware.
引文
[1]张春田,苏育挺,张静,数字图象压缩标准,北京,清华大学出版社,2006:28-33。
[2] CCITT , Video CODEC for audiovisual services at px64kbit/s , CCITT Recommendation H.261,1990。
[3] ISO/IEC,Coding of Moving Pictures and Associated Audio for Digital Storage Media at Up to about 1.5Mbit/s,ISO/IEC International Standard ll172-2,1993。
[4] The MPEG Home Page-MPEG-1,http://www.chiariglione.org/mpeg/standards/ mpeg-1/mpeg-1.htm。
[5] ISO/IEC , Information Technology-Generic Coding of Moving pictures and Associated Audio Information,ISO/IEC International Standard 13818,1995。
[6] ISO/IEC , Amendment 1 , Information technology-coding of audio-visual objects-Part 2: Visual,ISO/IEC International Standard 14496,2001。
[7] ITU-T,Video coding for low bit rate communication, Recommendation H.263,1996。
[8] ITU-T,ISO/IEC,Advanced video coding for generic audiovisual services, Recommendation H.264,2003。
[9] Bojun Meng,Oscar C.Au,Fast Intra-Prediction Mode Selection for 4×4Blocks in H.264 [J],ICASSP,2003
[10]Feng Pan,Xiao Lin et al,Fast Mode Decision for Intra Prediction in H.264/AVC Video Coding,IEEE Transaction on Circuits and Systems for Video Technology,2005,15(7):813-822.。
[11]Chang-sung Kim,Qing Li and C.-C.Jay Kuo,Fast Intra-Prediction Model Selection for H.264 Codec[J],Proceedings of the Society of Photo-optical Instrumentation Engineers(SPIE),2003,VI 524I:99-110。
[12] P.Yin,H.Y.C. Tourapis,A.M. Tourapis,etc,Fast mode decision and motion estimation for JVT/H.264 [A],Proceedings of International Conference on Image Processing,2003:853-856。
[13] J.F.Wang,J.C.Wang,J.T.Chen,etc,A Novel Fast Algorithm for Intra Mode Decision in H.264/AVC Encoders,ISCAS,2006:3498-3501。
[14] An-Chao Tsai,Jhing-Fa Wang,etc,A Simple and Robust Direction Detection Algorithm for Fast H.264 Intra Prediction,ICME,2007:1587-1590。
[15]周宁兆,宋彬,H.264中帧内编码算法及其快速实现研究[J],中国有线电视,2004年,29期:9-13。
[16]张春田,苏育挺,张静,数字图象压缩标准,北京,清华大学出版社,2006:2-3。
[17] ITU Telecom,Advanced video coding for generic audiovisual services[S], ITU-T Recommendation H.264,2003。
[18] Thomas Wiegand,Gary J.Sullivan,etc,Overview of the H.264/AVC Video Coding Standard[J],IEEE transactions on Circuits and Systems for Video Technology,2003,13(7):560-576。
[19]毕厚杰,新一代视频压缩编码标准——H.264/AVC,北京,人民邮电出版社,2005:92-94。
[20] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:171-177。
[21]余兆明,查日勇,黄磊等,图象编码标准H.264技术,北京,人民邮电出版社,2006:14-21。
[22] Joint Video Team (JVT) , Reference Software JM [CP] , http://bs.hhi.de/ ~suehrin/tml/download/,2005。
[23] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:180-181。
[24] X.Jing,L.-P.Chau,Fast approach for H.264 inters mode decision,Electronics Letters,2004,44(17)。
[25] Mehmet Kucukgoz,Ming-Ting Sun,Early-stop and motion vector re-using for MPEG-2 to H.264 transcoding,Visual Communication and Image Processing, 2004,,Vol.5308:932-936。
[26] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:170-176。
[27] N.Ahmed , T.Natrajan , K.R.Rao , Discrete cosine transform , IEEE Trans.Computers,1974。
[28] W-H.Chen,C.H.Smith,S.C.Fralick,A fast computational algorithm for the discrete cosine transforms,IEEE Trans.Communications,1977,25(9)。
[29]YonghongZeng,LizhiCheng,etc,Integer DCTs and Fast Algorithms,IEEE Transactions on Signal Processing,2001,49(11):2774-2782。
[30] Nam Ik Cho,Student Member,Sang Uk Lee,A Fast 4x4 DCT Algorithm for the Recursive 2-D DCT,IEEE Transaction on Signal Processing,1992,40(9):2166-2173。
[31] Malvar H.S,Hallapuro A,Karczewicz M,etc,Low-complexity transform and quantization in H.264/AVC,IEEE Transactions on Circuits and Systems for Video Technology,2003,13(7):598-603。
[32] H.S.Malvar,Low-Complexity legth-4 transform and quantization with 16-bit arithmetic,ITU-T SG16,2001。
[33]惠璤,基于H.264的变换与量化技术的研究与实现,[工学硕士论文],西安,西安电子科技大学,2004。
[34]毕厚杰,新一代视频压缩编码标准——H.264/AVC,北京,人民邮电出版社,2005:126-127。
[35] Detlev Marpe,Heiko Schwarz,Thomas Wiegand,Context-Based Adaptive Binary Arithmetic Coding in the H.264/AVC Video Compression Standard , IEEE Transaction on Circuits and Systems for Video Technology,2003,13(7):620-636。
[36] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:241-243。
[37]周宁兆,视频编码标准H.264及其快速实现算法研究,[工学学位论文],西安,西安电子科技大学,2005。
[38] J.Chou,M.Crouse,K.Ramchandran,A simple algorithm for removing blocking artifacts in block transform coded images,IEEE Signal Processing Letters,1998。
[39] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:262-264。
[40] Mingqiang Jiang,Nam Ling,On Lagrange Multiplier and Quantizer Adjustment for H.264 Frame-Layer Video Rate Control , IEEE Transactions on Circuits and Systems Video Technology,2006,16(5):663-669。
[41]章毓晋,图象处理与分析,北京,清华大学出版社,2004:179-181。
[42]陆宗骐,梁诚,用Sobel算子细化边缘,中国图象图形学报,2000,5(6):516-520。
[43]肖广,滕国伟,王国中,一种基于H.264/AVC的帧内预测模式快速选择算法,中国图象图形学报,2005,10(11):1375-1378。
[44] G.Bjontegaard,Calculation of average PSNR difference between RD-curves, 13th VCEG-M33 Meeting,Austin,TX,2001。
[45] Thomas Sikora,The MPEG-7 Visual Standard for Content Description—An Overview,IEEE,2001,11(6):696-702。
[2] CCITT , Video CODEC for audiovisual services at px64kbit/s , CCITT Recommendation H.261,1990。
[3] ISO/IEC,Coding of Moving Pictures and Associated Audio for Digital Storage Media at Up to about 1.5Mbit/s,ISO/IEC International Standard ll172-2,1993。
[4] The MPEG Home Page-MPEG-1,http://www.chiariglione.org/mpeg/standards/ mpeg-1/mpeg-1.htm。
[5] ISO/IEC , Information Technology-Generic Coding of Moving pictures and Associated Audio Information,ISO/IEC International Standard 13818,1995。
[6] ISO/IEC , Amendment 1 , Information technology-coding of audio-visual objects-Part 2: Visual,ISO/IEC International Standard 14496,2001。
[7] ITU-T,Video coding for low bit rate communication, Recommendation H.263,1996。
[8] ITU-T,ISO/IEC,Advanced video coding for generic audiovisual services, Recommendation H.264,2003。
[9] Bojun Meng,Oscar C.Au,Fast Intra-Prediction Mode Selection for 4×4Blocks in H.264 [J],ICASSP,2003
[10]Feng Pan,Xiao Lin et al,Fast Mode Decision for Intra Prediction in H.264/AVC Video Coding,IEEE Transaction on Circuits and Systems for Video Technology,2005,15(7):813-822.。
[11]Chang-sung Kim,Qing Li and C.-C.Jay Kuo,Fast Intra-Prediction Model Selection for H.264 Codec[J],Proceedings of the Society of Photo-optical Instrumentation Engineers(SPIE),2003,VI 524I:99-110。
[12] P.Yin,H.Y.C. Tourapis,A.M. Tourapis,etc,Fast mode decision and motion estimation for JVT/H.264 [A],Proceedings of International Conference on Image Processing,2003:853-856。
[13] J.F.Wang,J.C.Wang,J.T.Chen,etc,A Novel Fast Algorithm for Intra Mode Decision in H.264/AVC Encoders,ISCAS,2006:3498-3501。
[14] An-Chao Tsai,Jhing-Fa Wang,etc,A Simple and Robust Direction Detection Algorithm for Fast H.264 Intra Prediction,ICME,2007:1587-1590。
[15]周宁兆,宋彬,H.264中帧内编码算法及其快速实现研究[J],中国有线电视,2004年,29期:9-13。
[16]张春田,苏育挺,张静,数字图象压缩标准,北京,清华大学出版社,2006:2-3。
[17] ITU Telecom,Advanced video coding for generic audiovisual services[S], ITU-T Recommendation H.264,2003。
[18] Thomas Wiegand,Gary J.Sullivan,etc,Overview of the H.264/AVC Video Coding Standard[J],IEEE transactions on Circuits and Systems for Video Technology,2003,13(7):560-576。
[19]毕厚杰,新一代视频压缩编码标准——H.264/AVC,北京,人民邮电出版社,2005:92-94。
[20] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:171-177。
[21]余兆明,查日勇,黄磊等,图象编码标准H.264技术,北京,人民邮电出版社,2006:14-21。
[22] Joint Video Team (JVT) , Reference Software JM [CP] , http://bs.hhi.de/ ~suehrin/tml/download/,2005。
[23] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:180-181。
[24] X.Jing,L.-P.Chau,Fast approach for H.264 inters mode decision,Electronics Letters,2004,44(17)。
[25] Mehmet Kucukgoz,Ming-Ting Sun,Early-stop and motion vector re-using for MPEG-2 to H.264 transcoding,Visual Communication and Image Processing, 2004,,Vol.5308:932-936。
[26] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:170-176。
[27] N.Ahmed , T.Natrajan , K.R.Rao , Discrete cosine transform , IEEE Trans.Computers,1974。
[28] W-H.Chen,C.H.Smith,S.C.Fralick,A fast computational algorithm for the discrete cosine transforms,IEEE Trans.Communications,1977,25(9)。
[29]YonghongZeng,LizhiCheng,etc,Integer DCTs and Fast Algorithms,IEEE Transactions on Signal Processing,2001,49(11):2774-2782。
[30] Nam Ik Cho,Student Member,Sang Uk Lee,A Fast 4x4 DCT Algorithm for the Recursive 2-D DCT,IEEE Transaction on Signal Processing,1992,40(9):2166-2173。
[31] Malvar H.S,Hallapuro A,Karczewicz M,etc,Low-complexity transform and quantization in H.264/AVC,IEEE Transactions on Circuits and Systems for Video Technology,2003,13(7):598-603。
[32] H.S.Malvar,Low-Complexity legth-4 transform and quantization with 16-bit arithmetic,ITU-T SG16,2001。
[33]惠璤,基于H.264的变换与量化技术的研究与实现,[工学硕士论文],西安,西安电子科技大学,2004。
[34]毕厚杰,新一代视频压缩编码标准——H.264/AVC,北京,人民邮电出版社,2005:126-127。
[35] Detlev Marpe,Heiko Schwarz,Thomas Wiegand,Context-Based Adaptive Binary Arithmetic Coding in the H.264/AVC Video Compression Standard , IEEE Transaction on Circuits and Systems for Video Technology,2003,13(7):620-636。
[36] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:241-243。
[37]周宁兆,视频编码标准H.264及其快速实现算法研究,[工学学位论文],西安,西安电子科技大学,2005。
[38] J.Chou,M.Crouse,K.Ramchandran,A simple algorithm for removing blocking artifacts in block transform coded images,IEEE Signal Processing Letters,1998。
[39] Iain E. G. Richardson,H.264 and MPEG-4 Video Compression,England,John Wiley &Sons Ltd,2003:262-264。
[40] Mingqiang Jiang,Nam Ling,On Lagrange Multiplier and Quantizer Adjustment for H.264 Frame-Layer Video Rate Control , IEEE Transactions on Circuits and Systems Video Technology,2006,16(5):663-669。
[41]章毓晋,图象处理与分析,北京,清华大学出版社,2004:179-181。
[42]陆宗骐,梁诚,用Sobel算子细化边缘,中国图象图形学报,2000,5(6):516-520。
[43]肖广,滕国伟,王国中,一种基于H.264/AVC的帧内预测模式快速选择算法,中国图象图形学报,2005,10(11):1375-1378。
[44] G.Bjontegaard,Calculation of average PSNR difference between RD-curves, 13th VCEG-M33 Meeting,Austin,TX,2001。
[45] Thomas Sikora,The MPEG-7 Visual Standard for Content Description—An Overview,IEEE,2001,11(6):696-702。