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1.
The H.264/AVC video coding standard uses an intra prediction mode with 4×4 and 16×16 blocks for luma and 8×8 blocks for chroma. This standard uses the rate distortion optimization （RDO） method to determine the best coding mode based on the compression performance and video quality. This method offers a large improvement in coding efficiency compared to other compression standards, but the computational complexity is greater due to the various intra prediction modes. This paper proposes a fast intra mode decision algorithm for real-time encoding of H.264/AVC based on the dominant edge direction （DED）. The DED is extracted using pixel value summation and subtraction in the horizontal and vertical directions. By using the DED, three modes instead of nine are chosen for RDO calculation to decide on the best mode in the 4×4 luma block. For the 16×16 luma and the 8 × 8 chroma, only two modes are chosen instead of four. Experimental results show that the entire encoding time saving of the proposed algorithm is about 67% compared to the full intra search method with negligible loss of quality. 相似文献
2.
1 Introduction The emerging H.264/AVC video coding standard hasbeen developed and standardized collaboratively byboth ITU-T VCEG and ISO/IEC MPEG organizations .As the newest international video coding standard ,H.264/AVC represents a number of advances i… 相似文献
3.
In this paper, a fast mode decision algorithm for inter macroblocks in H.264/AVC is proposed, The algorithm is able to classify all modes by both gradient operator and comparison of space-time correlation. Because only part of modes is used to compare with each other the computational complexity can be reduced greatly. The simulation results show that it takes about 75 % of encoding time for other algorithm with similar visual quality. 相似文献
4.
With advanced prediction modes of intra prediction, intra coding of H.264/AVC offers significant coding gains compared with previous video coding standards. It uses an important tool called Lagrangian rate-distortion optimization (RDO) technique to decide the best coding mode for a block, but the computational burden is extremely high. In this paper, we proposed an improved fast intra prediction algorithm including block type selection and mode decision algorithm based on analysis of edge feature of a block. Our algorithm filters out unlikely block type and candidate modes to reduce the RDO calculations. Experimental results showed that the proposed algorithm can reduce the computation complexity of intra prediction from 52.90% to 56.31%, with 0.04 dB PSNR degradation and 2% increase of bit rate. 相似文献
5.
H．264／AVC在帧间运动估计／补偿编码过程中定义了7种帧间编码模式，并采用率失真优化全遍历策略来选择最优模式，这使计算复杂度急剧增加．针对这一问题，阐明了需对如何准确、快速地对块预测模式做出选择进行相关的研究．并就利用自然图像序列中相邻帧所表现出的强相关性提出了一种快速的帧间编码模式选择算法，通过计算部分编码模式来减少计算的复杂性．实验结果表明，该方法平均节省时间约18％，比特率平均下降约0．02％，而PSNR平均仅仅降低0．02dB． 相似文献
6.
The new H.264 video coding standard achieves significantly higher compression performance than MPEG-2. As the MPEG-2 is popular in digital TV, DVD, etc., bandwidth or memory space can be saved by transcoding those streams into H.264 in these applications. Unfortunately, the huge complexity keeps transcoding from being widely used in practical applications. This paper proposes an efficient transcoding architecture with a smart downscaling decoder and a fast mode decision algorithm. Using the proposed architecture, huge buffering memory space is saved and the transcoding complexity is reduced. Performance of the proposed fast mode decision algorithm is validated by experiments. 相似文献
7.
In H.264 encoder, all possible coding modes should be checked to choose the most appropriate mode for every macroblock, which adds a heavy computation burden to the encoder. In this paper, a fast inter-mode decision method is presented to reduce computation complexity of an H.264 encoder. By detecting the best matching block （BMB） before transform and quantization, some coding modes can be skipped and the corresponding encoding steps can be omitted for these BMBs. Meanwhile this method can also be used to detect all-zero blocks. The experimental results show that this method achieves consistently significant reduction of encoding time while keeping almost the same rate-distortion performance. 相似文献
8.
Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resilient coding scheme for H.264 and uses techniques of mode decision, data hiding, and error concealment to reduce the damage from error propagation. This paper proposes a system with two error resilience techniques that can improve the robustness of H.264 in noisy channels. The first technique is Nearest Neighbor motion compensated Error Concealment (NNEC) that chooses the nearest neighbors in the reference frames for error concealment. The second technique is Distortion Estimated Mode Decision (DEMD) that selects an optimal mode based on stochastically distorted frames. Observed simulation results showed that the rate-distortion performances of the proposed algorithms are better than those of the compared algorithms. 相似文献
9.
It is worth to mention that Eq.（19） can be found alternatively first by describing the boundary conditions at each of the sampling points to obtain a set of linear equations with respect to the modal coefficients Then, determining the number of sampling points in order that the number of linear equations be twice the number of unknowns 相似文献
10.
CHEN Zhi-kui 《浙江大学学报(A卷英文版)》2006,7(5):910-918
INTRODUCTION Recommendation H.264 was approved by ITU-T in May 2003 and the approved draft specifi cation is available for public review (Wiegand, 2003) The H.264 video codec has a very broad application range that covers all forms of digital compressed video from low bit rate Internet streaming applica tions to HDTV broadcast and digital cinema applica tions with near lossless coding. About 50% band width would be saved by using H.264 when compared to the existing most efficient com… 相似文献
11.
秦秀贵 《山东教育学院学报》2008,23(5):95-97
H.264/MPEG-4 AVC定义了9种4×4亮度块的预测模式,在参考模型JM中所采用的RDO计算复杂度较高。本文提出了一种基于各向同性Sobel算子的H.264的快速帧内编码模式选择算法,降低预测的复杂度,提高编码速度。测试表明,此算法能够使编码速度提高将近75%。 相似文献
12.
The existing H.264/AVC rate control schemes rarely include the perceptual considerations. As a result, the improvements in visual quality are hardly comparable to those in peak signal-to-noise ratio （PSNR）. In this paper, we propose a perceptual importance analysis scheme to accurately abstract the spatial and temporal perceptual characteristics of video contents. Then we perform bit allocation at macroblock （MB） level by adopting a perceptual mode decision scheme, which adaptively updates the Lagrangian multiplier for mode decision according to the perceptual importance of each MB. Simulation results show that the proposed scheme can efficiently reduce bit rates without visual quality degradation. 相似文献
13.
针对H．264推荐的误码掩盖方法不能有效恢复受损图像，根据受损块的时空域相关性，提出一种自适应误码掩盖算法（AEC）．实验表明，从PSNR和主观质量上，本文算法均明显优于传统方法． 相似文献
14.
在H.264编码算法的基础上,提出了多参考帧的运动估计快速算法--三维菱形搜索法(TDDS).实验结果表明,与未使用快速算法相比,使用本文提出的快速算法,在平均码率增加不到0.1%,恢复图像平均PSNR(峰值信噪比)下降不到0.1dB的情况下,编码速度提高2.5倍,满足实时视频通信的要求.算法与H.264标准兼容,可用于实际产品. 相似文献
15.
可伸缩视频编码（Scalable Video Coding,SVC）一般采用实时传输协议（Real-time TransportProtocol,RTP）保证视频数据流的实时传输和质量监测。本文在分析SVC码流结构和RTP协议的基础上实现了H.264/SVC视频数据的RTP封装算法,提出了一种基本层与增强层分离的灵活封装机制模拟SVC在不同差错信道中的传输,通过在H.264/SVC模拟测试环境中的实验证明RTP封装机制的有效性,标准兼容性和可扩展性。 相似文献
16.
帧内预测是H.264视频编解码标准中重要的组成部分,它能够显著提高压缩比率,但是大大提高了计算复杂度,很难运用到实时传输中,因此,如何提高运算速率是改进算法的核心问题。提出了一种快速模式选择算法,在保证图像质量的情况下较大地提高了帧内编码速度。 相似文献
17.
网络视频监控系统研究 总被引：2，自引：0，他引：2
视频监控系统是安全防范系统的组成部分，它是 一种防范能力较强的综合系统。视频监控系统在公 安、金融证券、银行、商店、宾馆、智能大厦以及重要部 门、社区的安全方面能起到重要的作用。目前，广泛应 用的监控系统采用模拟技术。近年来，随着计算机、 网络以及图像处理、传 相似文献
18.
李小红 《合肥联合大学学报》2005,15(3):21-24
H．264标准是ITU—T视频编码专家组（VcEG）和ISO／IECMPEG委员会正在制定的用于视频通信的新一代视频编码标准。运动估计是H．264最关键技术，占计算量的主要部分，因而成为视频压缩处理的瓶颈，因此必须研究运动估计的并行处理算法。通过介绍SSE技术的特点、数据结构和内联函数，在此基础上用SSE技术实现了运动估计并行算法。 相似文献
19.
Motion estimation is an important part of the MPEG-4 encoder, due to its significant impact on the bit rate and the output quality of the encoder sequence. Unfortunately this feature takes a significant part of the encoding time especially when the straightforward full search(FS) algorithm is used. In this paper, a new algo-rithm named diamond block based gradient descent search (DBBGDS) algorithm, which is significantly faster than FS and gives similar quality of the output sequence, is proposed. At the same time, some other algo-rithms, such as three step search (TSS), improved three step search (ITSS), new three step search (NTSS),four step search (4SS) , cellular search (CS) , diamond search (DS) and block based gradient descent search (BBGDS) , are adopted and compared with DBBGDS. As the experimental results show, DBBGDS has its own advantages. Although DS has been adopted by the MPEG-4 VM, its output sequence quality is worse than that of the proposed algorithm while its complexity is similar to the proposed one. Compared with BBGDS, the proposed algorithm can achieve a better output quality. 相似文献
20.
研究一种针对H.264编码的帧间预测块划分视频水印算法,该算法先对水印图像进行二值处理,然后在H.264帧间预测编码时根据水印二值序列选择不同的区块划分,并将水印值嵌入进去.实验结果表明,该算法具有较好的实时性、鲁棒性. 相似文献