一种改进的R-λ模型码率控制算法
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摘要
码率控制是视频编码系统中的重要模块,用于控制编码器输出特定目标的码率,并使编码视频失真最小。R-λ模型码率控制方法是新一代视频编码标准HEVC中推荐的码率控制算法,其主要包括固定比例比特分配和自适应比率比特分配两种码率控制策略。为了提高R-λ模型码率控制算法的码率控制精度和率失真性能,文中提出了相应的算法改进。首先,根据图像组的编码结构设计了精确的率失真模型参数更新方法;其次,根据率失真依赖关系改进了图像组层的比特分配策略;最后,提出动态的图像组层拉格朗日乘子和编码帧比特权重计算方法。实验结果显示,所提方法在低延迟P帧和B帧配置下,码率相对误差仅为0.006%和0.005%,相比自适应比率比特分配码率控制策略,改进方法的率失真性能提高了1.2%和1.3%。
Rate control is an important module in video coding systems,which makes an encoder output specific bit rates,and minimizes the distortion of encoded videos.The R-λ model based rate control is recommended in high efficiency video coding(HEVC) international video coding standard,which mainly includes two schemes,i.e.,the fixed ratio bit allocation and the adaptive ratio bit allocation.In order to improve both the accuracy of rate control and the rate-distortion(R-D) performance,this paper proposed an improved R-λ model based rate control algorithm.Firstly,an accurate R-D model update method is designed according to the coding structure of group of picture(GOP).Secondly,the GOP-level bit allocation scheme is improved according to the relationship of R-D dependency.Finally,the calculation formulas of the dynamic Lagrange multiplier at GOP-level and the dynamic bit weight for the frame to be encoded are proposed.Experimental results demonstrate that the bit rate relative errors of the proposed method are only about 0.006% and 0.005%,and achieves average 1.2% and 1.3% R-D performance gains compared with the adaptive ratio bit allocation scheme under the low delay configuration of P and B frames,respectively.
Rate control is an important module in video coding systems,which makes an encoder output specific bit rates,and minimizes the distortion of encoded videos.The R-λ model based rate control is recommended in high efficiency video coding(HEVC) international video coding standard,which mainly includes two schemes,i.e.,the fixed ratio bit allocation and the adaptive ratio bit allocation.In order to improve both the accuracy of rate control and the rate-distortion(R-D) performance,this paper proposed an improved R-λ model based rate control algorithm.Firstly,an accurate R-D model update method is designed according to the coding structure of group of picture(GOP).Secondly,the GOP-level bit allocation scheme is improved according to the relationship of R-D dependency.Finally,the calculation formulas of the dynamic Lagrange multiplier at GOP-level and the dynamic bit weight for the frame to be encoded are proposed.Experimental results demonstrate that the bit rate relative errors of the proposed method are only about 0.006% and 0.005%,and achieves average 1.2% and 1.3% R-D performance gains compared with the adaptive ratio bit allocation scheme under the low delay configuration of P and B frames,respectively.
引文
[1] GUO H W,ZHU C,ZHOU Y M.Recent advances on rate control for HEVC[J].Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition),2018,30(2):199-209.(in Chinese)郭红伟,朱策,周益民.HEVC码率控制技术的研究进展[J].重庆邮电大学学报(自然科学版),2018,30(2):199-209.
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[7] WANG M H,NGAN K N,LI H L.An Efficient Frame-Content Based Intra Frame Rate Control for High Efficiency Video Co-ding[J].IEEE Signal Processing Letters,2015,22(7):896-900.
[8] WANG M H,NGAN K N,LI H L.Low-Delay Rate Control for Consistent Quality Using Distortion-Based Lagrange Multiplier [J].IEEE Transactions on Image Processing,2016,25(7):2943-2955.
[9] SEO C W,MOON J H,HAN J K.Rate Control for Consistent Objective Quality in High Efficiency Video Coding [J].IEEE Transactions on Image Processing,2013,22(6):2442-2454.
[10] YANG S H,VO P B.Adaptive Bit Allocation for Consistent Video Quality in Scalable High-Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Techno-logy,2017,27(7):1555-1567.
[11] LI L,LI B,LI H,et al.λ Domain Optimal Bit Allocation Algorithm for High Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Technology,2018,28(1):130-142.
[12] KIM I,MCCANN K,SUGIMOTO K,et al.High Efficiency Video Coding (HEVC) Test Model 11 (HM11) Encoder Description [C]//Document JCTVC-M1002.Incheon,KR,2013.
[13] LI B,XU J Z,ZHANG D,et al.QP Refinement According to Lagrange Multiplier for High Efficiency Video Coding [C]//International Symposium on Circuits and Systems (ISCAS).Beijing,China:IEEE,2013:477-480.
[14] LI H Q,LI B,XU J Z.Rate-Distortion Optimized Reference Picture Management for High Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Technology,2012,22(12):1844-1857.
[15] HUANG T Y,JOHARI R,MCKEOWN N,et al.A Buffer- Based Approach to Rate Adaptation:Evidence from a Large Video Streaming Service [J].Acm Sigcomm Computer Communication Review,2014,44(4):187-198.
[16] BOSSEN F.Common Test Conditions and Software Reference Configurations [C]//Document JCTVC-L1100.Geneva,Swit-zerland,2013.
[17] BJONTEGAARD G.Calculation of average PSNR difference between RDcurves [C]//Document VCEG-M33.Austin,Texas,USA,2001.
[2] SULLIVAN G J,OHM J R,HAN W J,et al.Overview of the High Efficiency Video Coding (HEVC) Standard [J].IEEE Transactions on Circuits and Systems for Video Technology,2012,22(12):1649-1668.
[3] CHOI H,YOO J,NAM J,et al.Pixel-Wise Unified Rate- Quantization Model for Multi-Level Rate Control [J].IEEE Journal of Selected Topics in Signal Processing,2013,7(6):1112-1123.
[4] LI B,LI H Q,LI L,et al.λ Domain Rate Control Algorithm for High Efficiency Video Coding [J].IEEE Transactions on Image Processing,2014,23(9):3841-3854.
[5] ZUPANCIC I,NACCARI M,MRAK M,et al.Two-Pass Rate Control for Improved Quality of Experience in UHDTV Delivery[J].IEEE Journal of Selected Topics in Signal Processing,2017,11(1):167-179.
[6] WEN J T,FANG M Y,TANG M H,et al.R-lambda Model Based Improved Rate Control for HEVC with Pre-Encoding [C]//Data Compression Conference (DCC).Snowbird,UT,USA,2015:53-62.
[7] WANG M H,NGAN K N,LI H L.An Efficient Frame-Content Based Intra Frame Rate Control for High Efficiency Video Co-ding[J].IEEE Signal Processing Letters,2015,22(7):896-900.
[8] WANG M H,NGAN K N,LI H L.Low-Delay Rate Control for Consistent Quality Using Distortion-Based Lagrange Multiplier [J].IEEE Transactions on Image Processing,2016,25(7):2943-2955.
[9] SEO C W,MOON J H,HAN J K.Rate Control for Consistent Objective Quality in High Efficiency Video Coding [J].IEEE Transactions on Image Processing,2013,22(6):2442-2454.
[10] YANG S H,VO P B.Adaptive Bit Allocation for Consistent Video Quality in Scalable High-Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Techno-logy,2017,27(7):1555-1567.
[11] LI L,LI B,LI H,et al.λ Domain Optimal Bit Allocation Algorithm for High Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Technology,2018,28(1):130-142.
[12] KIM I,MCCANN K,SUGIMOTO K,et al.High Efficiency Video Coding (HEVC) Test Model 11 (HM11) Encoder Description [C]//Document JCTVC-M1002.Incheon,KR,2013.
[13] LI B,XU J Z,ZHANG D,et al.QP Refinement According to Lagrange Multiplier for High Efficiency Video Coding [C]//International Symposium on Circuits and Systems (ISCAS).Beijing,China:IEEE,2013:477-480.
[14] LI H Q,LI B,XU J Z.Rate-Distortion Optimized Reference Picture Management for High Efficiency Video Coding [J].IEEE Transactions on Circuits and Systems for Video Technology,2012,22(12):1844-1857.
[15] HUANG T Y,JOHARI R,MCKEOWN N,et al.A Buffer- Based Approach to Rate Adaptation:Evidence from a Large Video Streaming Service [J].Acm Sigcomm Computer Communication Review,2014,44(4):187-198.
[16] BOSSEN F.Common Test Conditions and Software Reference Configurations [C]//Document JCTVC-L1100.Geneva,Swit-zerland,2013.
[17] BJONTEGAARD G.Calculation of average PSNR difference between RDcurves [C]//Document VCEG-M33.Austin,Texas,USA,2001.