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1.
In this paper, an efficient one-pass frame level rate control algorithm is proposed for H.264/AVC, where the two essential problems in rate control, i.e., the budget allocation (BA) and the quantization parameter determination (QPD) are both considered. First, an efficient BA scheme is designed with special consideration of the inter-frame dependency. Accordingly, the error propagation caused by improper QP assignment in the motion compensation process is reduced and the total distortion is kept at a low level. Second, a better QPD method is developed based on an accurate rate model and a second feedback mechanism so that a high rate accuracy is guaranteed. Simulations verified the performance of the proposed algorithm. Compared with the fixed QP coding and the two recommended rate control algorithms (G012-MB and G012-Frame) in H.264/AVC reference software, up to 1.50, 1.12, and 0.94 dB were achieved with a higher rate accuracy in the coding efficiency test defined by ITU-T VCEG. Particularly, a more significant improvement was observed in slow movement scenarios: compared with G012-MB, a gain of 0.80 dB on average and 1.43 dB at maximum was obtained with 66.0% reduction of average rate mismatch. Compared with G012-Frame, the average and maximum gains are 0.34 and 1.06 dB, respectively. While at the same time, the average rate mismatch was reduced by 90.4%. Considering the low computational cost, the proposed algorithm is quite appealing to real-time video applications.  相似文献   

2.
Transparent encryption of video content requires to provide a video preview that is left in plaintext, while the enhancement information is encrypted. In this paper we propose three algorithms that provide transparent encryption. The first two ones are based on the idea of generating controlled drift in such a way as to obtain the desired quality level, while the third algorithm employs scalable video coding. We provide experimental results on several video sequences, as well as a security analysis, showing that the proposed algorithms provide an effective framework to perform transparent encryption.  相似文献   

3.
In this paper, we present a new adaptive video coding control for real-time H.264/AVC encoding system. The main techniques include: (1) the initial quantization parameter (QP) decision scheme is based on Laplacian of Gaussian (LoG) operators; (2) the MB-level QP calculation is based on the spatio-temporal correlation, in which the computation is less than the quadratic model used by H.264/AVC; (3) the adaptive GOP structure is proposed, in which the I-frame is adaptively replaced by an enhancement P-frame to improve the coding efficiency; (4) the scene change is detected with the complexity of adjacent inter-frames and the appropriate QP is re-calculated for the scene-change frame. The proposed algorithm is not only to save the computational complexity but also to improve coding quality. Compared to the JM12.4 reference under various sequences testing, the proposed algorithm can decrease coding time by 64.5% and improve PSNR by 1.52 dB while keeping the same bit-rate.  相似文献   

4.
This article presents an efficient rate control scheme for H.264/AVC video coding in low bit rate environment. In the proposed scheme, an improved rate-distortion (RD) model by both analytical and empirical approaches is developed. It involves an enhanced mean absolute difference estimating method and a more rate-robust distortion model. Based on this RD model, an efficient macroblock-layer rate control scheme for H.264/AVC video coding is proposed. Experimental results show that this model encodes video sequences with higher peak signal-to-noise ratio gains and generates bit stream closer to the target rate.  相似文献   

5.
H.264/AVC中基于全零块检测的运动估计快速算法   总被引:5,自引:0,他引:5  
全零块检测是面向低比特率的视频编码器常用优化方法之一.特别是与运动估计相结合,可以有效的减少编码器的计算复杂性.本文根据H.264/AVC中整数变换的特点,给出了相应的全零块检测门限,提出了一种基于全零块检测的运动搜索提前中止准则.针对H.264/AVC多编码模式的特点,进一步将全零块检测用于H.264/AVC中多种编码模式的选择,有效的提高了运动估计的效率.利用这种方法,在有效减少编码器的计算复杂性,提高H.264/AVC软件编码器编码效率的同时,可以保持比特率和图像质量基本不变.  相似文献   

6.
In this letter, an adaptive scanning that improves intra coding efficiency in the H.264/AVC standard is proposed. The proposed adaptive scanning utilizes the prediction directions (modes) that include the horizontal and vertical edge information in a block. Depending on the prediction directions, the proposed method uses three scanning methods: zigzag scanning, horizontal scanning, and vertical scanning. In the proposed method, horizontal and vertical scanning are used in vertical and horizontal prediction modes, respectively, and the normal zigzag scanning in the H.264 standard is used in all other intra prediction modes. The proposed method reduces the bit rate by approximately 2.5% compared with H.264/AVC, without the degradation of video quality.  相似文献   

7.
A real-time dual watermarking algorithm of H.264/AVC compressed video is proposed for Video-on-Demand (VOD) service. The copyright information and user information are modulated by CDMA spreading strategies as watermark. At the encoder side, copyright information is embedded into the first non-zero coefficient of Intra 4 × 4 coded blocks in the luminance components of I frames. An effective error compensation mechanism is simultaneously introduced into the embedding process, which strictly restricts the distortion caused by quantization and watermark embedding within a step size of quantization. At the server side, a XOR based mapping rule is utilized for watermark embedding because the number of non-zero coefficients after quantization is quite less in P frames. Every two bits of the private user information is mapped to three non-zero coefficients of P frames. Experimental results on test sequences demonstrate that the proposed approach has just slight influence on bit rate and PSNR with real-time performance for VOD services, and achieves the dual purposes of copyright protection and pirate tracking.  相似文献   

8.
The H.264/AVC Fractional Motion Estimation (FME) with rate-distortion constrained mode decision can improve the rate-distortion efficiency by 2–6 dB in peak signal-to-noise ratio. However, it comes with considerable computation complexity. Acceleration by dedicated hardware is a must for real-time applications. The main difficulty for FME hardware implementation is parallel processing under the constraint of the sequential flow and data dependency. We analyze seven inter-correlative loops extracted from FME procedure and provide decomposing methodologies to obtain efficient projection in hardware implementation. Two techniques, 4×4 block decomposition and efficiently vertical scheduling, are proposed to reuse data among the variable block size and to improve the hardware utilization. Besides, advanced architectures are designed to efficiently integrate the 6-taps 2D finite impulse response, residue generation, and 4×4 Hadamard transform into a fully pipelined architecture. This design is finally implemented and integrated into an H.264/AVC single chip encoder that supports realtime encoding of 720×480 30fps video with four reference frames at 81 MHz operation frequency with 405 K logic gates (41.9% area of the encoder).
Liang-Gee ChenEmail:
  相似文献   

9.
视频编码H.264/AVC新技术及其优化   总被引:1,自引:0,他引:1  
本文详细介绍了视频编码新标准H.264/AVC中的运动估计和运动补偿、预测、证书变换、量化、熵编码环路滤波、帧切换等技术及其优化设计.  相似文献   

10.
Hierarchical B-frames can bring high coding performance when introduced into H.264/AVC.However,the traditional rate control schemes can not work efficiently in such new coding framework.This article presents a rate control algorithm for hierarchical B-frames in H.264/AVC.Taking the feature of the dyadic hierarchical coding structure into consideration,the proposed algorithm includes group of pictures(GOP)layer,temporal layer and frame layer bits allocation.After frame layer bits allocation is complete,frame layer quantization parameters(QP)determination strategy is responsible for calculating the final QP.Experimental results show that compared with other rate control algorithms,the proposed one can improve the coding performance and reduce the mismatch of target bit rate and real bit rate.  相似文献   

11.
论文提出基于宏块类型空域预测的自适应宏块编码算法,并在H.264/AVC验证模型JM7.6上实现了所提出的自适应算法。大量的实验表明,论文提出的自适应算法不仅大大提高了图像编码的速度,而且图像编码质量和压缩效率基本不受影响,缓解了率失真优化算法的缺陷,极大地提高了编码器的工作效率。  相似文献   

12.
Deblocking filter is one of the most time consuming modules in the H.264/AVC decoder as indicated in many studies. Therefore, accelerating deblocking filter is critical for improving the overall decoding performance. This paper proposes a novel parallel algorithm for H.264/AVC deblocking filter to speed the H.264/AVC decoder up. We exploit pixel-level data parallelism among filtering steps, and observe that results of each filtering step only affect a limited region of pixels. We call this “the limited propagation effect”. Based on this observation, the proposed algorithm could partition a frame into multiple independent rectangles with arbitrary granularity. The proposed parallel deblocking filter algorithm requires very little synchronization overhead, and provides good scalability. Experimental results show that applying the proposed parallelization method to a SIMD optimized sequential deblocking filter achieves up to 95.31% and 224.07% speedup on a two-core and four-core processor, respectively. We have also observed a significant speedup for H.264/AVC decoding, 21% and 34% on a two-core and four-core processor, respectively.
Ja-Ling WuEmail:

Sung-Wen Wang   received his Ph.D. degree in computer science from National Taiwan University, Taipei, Taiwan, in 2008. His general research interests are in the field of digital video coding, codec-processor architecture co-design and multimedia systems optimization, especially in video coding technology optimization. Shu-Sian Yang   received the B.S. and M.S. degrees in computer science and information engineering from National Taiwan University, Taiwan, in 2005 and 2007, respectively. His current research interests include video compression, image processing, and multimedia application. He is currently working at PixArt Imaging Inc., HsinChu, Taiwan as a senior engineer. Hong-Ming Chen   received the B.S. degree in computer science and information engineering from National Taiwan University, Taiwan, in 2007. He is currently pursuing the M.S. degree in the same department in National Taiwan University. His current research interests include video compression, image processing, digital content analysis, and multimedia application. Chia-Lin Yang   received the B.S. degree from the National Taiwan Normal University, Taiwan, R.O.C., in 1989, the M.S. degree from the University of Texas at Austin in 1992, and the Ph.D. degree from the Department of Computer Science, Duke University, Durham, NC, in 2001. In 1993, she joined VLSI Technology Inc. (now Philips Semiconductors) as a Software Engineer. She is currently an Associate Professor in the Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan, R.O.C. Her research interests include energy-efficient microarchitectures, memory hierarchy design, and multimedia workload characterization. Dr. Yang is the recipient of a 2000-2001 Intel Foundation Graduate Fellowship Award and 2005 IBM Faculty Award. Ja-Ling Wu   (SM ’98, Fellow ’08) received his Ph.D. degree in electrical engineering from Tatung Institute of Technology, Taipei, Taiwan, in 1986. From 1986 to 1987, he was an Associate Professor of the Electrical Engineering Department, Tatung Institute of Technology. Since 1987, he transferred to the Department of Computer Science and Information Engineering(CSIE), National Taiwan University(NTU), Taipei, where he is presently a Professor. From 1996 to 1998, he was assigned to be the first Head of the CSIE Department, National Chi Nan University, Puli, Taiwan. During his sabbatical leave (from 1998 to 1999), Prof. Wu was invited to be the Chief Technology Officer of the Cyberlink Corp. In this one year term, he involved with the developments of some well-known audio-video softwares, such as the PowerDVD. Since Aug. 2004, Prof. Wu has been appointed to head the Graduate Institute of Networking and Multimedia, NTU. Prof. Wu has published more than 200 technique and conference papers. His research interests include digital signal processing, image and video compression, digital content analysis, multimedia systems, digital watermarking, and digital right management systems. Prof. Wu was the recipient of the Outstanding Young Medal of the Republic of China in 1987 and the Outstanding Research Award three times of the National Science Council, Republic of China, in 1998, 2000 and 2004, respectively. In 2001, his paper “Hidden Digital Watermark in Images” (co-authored with Prof. Chiou-Ting Hsu), published in IEEE Transactions on Image Processing, was selected to be one of the winners of the “Honoring Excellence in Taiwanese Research Award”, offered by ISI Thomson Scientific. Moreover, his paper “Tiling Slideshow” (co-authored with his students) won the Best Full Technical Paper Award in ACM Multimedia 2006. Professor Wu was selected to be one of the lifetime Distinguished Professors of NTU, November 2006. Prof. Wu has been elected to be IEEE Fellow, since 1 January 2008, for his contributions to image and video analysis, coding, digital watermarking, and rights management.   相似文献   

13.
H.264/AVC标准引入RDO技术计算帧内预测最优模式,提高编码效率,但同时RDO技术的引入极大提升编码端的计算复杂度.提出了一种针对帧内预测4×4亮度块的快速模式选择算法,该算法利用亮度块SATD值与RDO技术间的相关性,优化原有算法.实验结果表明,算法能在基本不影响图像原有质量的情况下,较大程度减少编码H.264序列所需时间.  相似文献   

14.
一种基于H.264/AVC的高效块匹配搜索算法   总被引:13,自引:2,他引:13  
薛金柱  沈兰荪 《电子学报》2004,32(4):583-586
本文针对H.264/AVC的编码特点,提出了一种利用时空域运动相关性的快速块匹配搜索算法.该算法充分利用了视频序列的运动程度与宏块编码模式间的关联特性以及运动矢量的统计特征,明显减少了运动估计的搜索复杂度.实验表明,本文方法的搜索速度分别比FS和DS算法平均提高了77.96%和32.19%;重建图像的PSNR比DS算法平均提高了0.06dB,更接近FS算法的编码质量.  相似文献   

15.
新一代视频编码标准H.264/AVC的关键技术研究   总被引:1,自引:0,他引:1  
张惠  张学武  张卓 《现代电子技术》2009,32(15):126-130
H.264/AVC是继H.263之后的新一代视频编码新标准,它采用了大量的新技术,适合各种媒体的传输和存储,可以面向交互式和非交互式应用.这里主要介绍了它的关键技术,通过仿真实验研究了H.264/AVC的优越性.实验结果表明,H.264/AVC在改善编码性能和提高编码效率以及传输鲁棒性方面与现有的任何标准相比,在同样保真度的条件下,可节省码率50%以上.  相似文献   

16.
提出了一种基于复杂度的率失真联合优化算法, 该算法在H.264/AVC视频编码标准中率失真优化算法的基础上考虑了视频编码算法复杂度因素, 以求达到对视频编码复杂度和率失真性能联合优化的效果, 并通过引入复杂度控制因子对编码复杂度进行控制调节。实验结果表明, 该算法可以在保证率失真性能降低很小的情况下降低视频编码的复杂度, 在率失真和复杂度之间取得了很好的均衡效果。  相似文献   

17.
提出了一种基于H.264/AVC的空域分级视频编码器方案,给出的实验结果表明,和不采用分级编码的H.264/AVC编码器相比,该方案的增强层编码器可以降低视频传输所需带宽约20%~30%,计及传输基本层后,总比特率也仅比不分级的比特率约增加不到10%.  相似文献   

18.
在分析了3G视频业务特点和适用于3G终端的容错技术后,针对流媒体和对话式视频业务提出了两种容错策略.实验结果表明,提出的容错策略针对流媒体业务和对话式业务,可以有效避免和降低传输丢包,并对解码后的视频质量有所改善.  相似文献   

19.
联合视频组(JVT)最近正在研究开发基于H.264/AVC标准的可伸缩视频编码(SVC)方法,并且准备将其纳入H.264/AVC标准的扩展中.本文概述了SVC的编码结构,并重点讲述了H.264/AVC可伸缩编码扩展的关键技术.  相似文献   

20.
张剑  张君昌 《电子设计工程》2012,20(11):187-189,192
为了提高JVT-H017码率控制提案中的基本单元层比特数分配方法在视频序列复杂度较高时分配的准确度,提出了一种视频复杂度自适应的基本单元层码率控制方法。利用DMAD参数来判断视频场景的复杂度,对JVT-H017的比特数分配方法进行了改进;同时提出了一种基本单元层编码的理想情况,并以此理想情况下的比特数消耗情况来对基本单元的比特数进行修正。仿真结果表明,该方法有效地提高了视频编码的峰值信噪比(PSNR),最大可提高0.49 dB,并且输出码率更接近预定编码码率。  相似文献   

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