一种H.264/AVC over MPEG-2流的解决方案

对如何将H．264／AVC视频流经MPEG-2的系统传输层传输提出了一种解决方案。要点是：先把H．264／AVC视频作为MPEG-2系统层传输的基本流，然后扩展MPEG-2标准中的传输流系统目标解码器（T-STD），使之可以将H．264／AVC编码视频作为MPEG．2传输流（TS）在Internet上传输和解码。被解码的基本流通常来自于一个“容器”文件（如AVI或者TS），在客户端从服务器端的这个容器中取出H．264／AVC基本流后便可实时解码、显示。仿真实验表明，该方案能够获得较好的流视频效果，在带宽受限的情况下信噪比低于40dB的帧数少于5％，可用于网络流视频或移动视频中。     

H.264/AVC编码模式选择

H．264／AVC是最新的视频编码标准。与以前的视频标准相比编码模式更多,压缩效率更高,同时在编码模式的选择上也更复杂,计算量更大。编码时如何选择合适的编码模式对H.264／AVC的压缩性能和计算复杂度是非常关键的。本文讲述了JVT的参考软件是如何实现H．264／AVC编码模式选择。     

基于MMX技术的H.264解码器优化

新一代视频编码标准H.264为了提高编码效率采用了一系列新技术，而这些新技术的使用也极大地增加了算法的复杂度。因此，在保持编码效率的同时如何提高编解码器的运算速度成为目前研究的热点问题之一。介绍了符合H.264基本规范的解码器的基本框架和解码流程；通过复杂度分析确定了解码过程中计算最为密集的两个模块，即插值、整数余弦变换和重建模块；提出了基于MMX技术的优化方法，并对这两个模块进行了重点优化。实验结果表明，利用这些优化方法可以使解码器的平均解码速度提高到原来的1．4-2．1倍，优化效果十分显著。     

H.264/AVC的特点及其在视频监控中的应用

H．264／AVC是视频编码专家组(VCEG)和活动图像专家组(MPEG)联合制定的新的视频编码标准,其目的就是解决以往标准暴露出来的缺点。文章首先指出目前采用其他标准设计视频监控系统的不足,分析了H．264／AVC视频编码标准的特点,指出H．264／AVC适于视频监控应用的优势所在,最后重点阐述了H．264／AVC标准中分层编码技术和SP／SI帧技术在视频监控中的应用。     

一种利用宏块直方图的快速帧间预测方法*

针对H.264/AVC编码复杂度高难以实时应用的缺陷,在深入研究H.264/AVC中重要且耗时的帧间预测编码技术的基础上,提出了一种融合宏块直方图分布信息的分层逐级预判的快速帧间预测算法。仿真实验结果表明,提出算法与H.264/AVC标准算法相比,在保持重建视频图像质量和输出码流结构的前提下,平均节省编码时间约70%,改善了编码复杂度与编码实时性,保持了H.264/AVC低码率的编码优势。该算法有效地提高了H.264/AVC的编码效率。     

H.264/AVC先进视频编码研究

为了取得更高的图像压缩性能和更多的实用功能，ISO／IEC MPEG(运动图像专家组)和ITU-TVCEG(视频编码专家组)共同制订了一套新的视频编码标准H．264／AVC。介绍了H．264／AVC图像编解码系统的实现过程，对其采用的新技术进行了描述，最后将其与H．263和MPEG-4标准进行了性能对比。     

H.264/AVC的复杂度分析以及实时实现

新发展的H.264/AVC比原有的视频编码标准大幅度提高了编码效率,但其运算复杂度也大大增加,影响了其推广。本文简要分析了H.264/AVC的复杂度,并指出对其优化的途径,提出了对其中的帧内预测编码和多尺度块模式搜索运动估计等主要模块的优化算法。实验结果显示可以实现对CIF格式的图像进行实时编码。     

基于H.264标准的视频解码优化及DSP实现

H.264视频编码标准是JVT提出的新视频编码标准.该标准在编码效率和传输可靠性方面与以前的标准相比有了更大的提高,但其运算复杂度也更大.指出H.264软件解码器的耗时部分模块,对其进行优化,并在DSP上实现.通过对QCIF视频序列的解码测试,优化后运行效率有了明显的提升,基本实现了实时解码.     

H.264视频编解码技术在视频无线通信系统中的应用

为了进一步提高压缩性能,重点进行了H.264编解码器的优化.依据应用需求,对H.264编码中运算复杂度最高的运动估计模块进行了算法改进.在对参考代码JM10.2解码器的性能进行复杂度分析的基础上,提出了一种基于码头分组的快速变长熵解码方法.     

低复杂度的H.264帧间宏块编码模式选择算法

为了减少H．264／AVC帧间编码模式选择的计算复杂度，利用不同编码模式在实际视频序列中的利用率信息及空时域相邻块之间的相关性，提出了一个低复杂度的快速帧间编码模式选择算法。模拟结果表明，该算法在保持率失真性能的前提下可以大幅度减少模式选择的计算复杂度，有利于H．264的实时应用。     

Simplified algorithms for rate-distortion optimization in high efficiency video coding

HEVC is the latest coding standard to improve the coding efficiency by a factor of two over the previous H.264/AVC standard at the cost of the increased complexity of computation rate-distortion optimization (RDO) is one of the computationally demanding operations in HEVC and makes it difficult to process the HEVC compression in real time with a reasonable computing power. This paper aims to present various simplified RDO algorithms with the evaluation of their RD performance and computational complexity. The algorithms for the simplified estimation of the sum of squared error (SSE) and context-adaptive binary arithmetic coding (CABAC) proposed for H.264/AVC are reviewed and then they are applied to the simplification of HEVC RDO. By modifying the previous algorithm for H.264/AVC, a new simplified RDO algorithm is proposed for modifying the previous algorithm for H.264/AVC to be optimized for the hierarchical coding structure of HEVC. Further simplification is attempted to avoid the transforms operations in RDO. The effectiveness of the existing H.264/AVC algorithms as well as the proposed algorithms targeted for HEVC is evaluated and the trade-off relationship between the RD performance and computational complexity is presented for various simplification algorithms. Experimental results show that reasonable combinations of RDO algorithms reduce the computation by 80–85% at the sacrifice of the BD-BR by 3.46–5.93% for low-delay configuration.     

A reduced reference video quality assessment of H.264 and mpeg2 codec based on sharpness metric

In this paper, we propose a new perceptually significant video quality metric for the H.264/Motion Picture Expert Group (MPEG)‐4 Advanced Video Coding (AVC) and MPEG2 standard. Our method operates in the spatial domain by using the Sobel filter. The proposed approach does not require a high computational complexity and can be suitable for real‐time evaluation. We evaluate the performance of the proposed method by using three Common Intermediate Format sequences at different compression rates. The comparison of the obtained results is made with some video quality models using “LIVE”, “IVP” and “IRCCyN/IVC 1080i” databases. The performance metrics, i.e. Pearson and Spearman correlation coefficients, indicate that the proposed method gives a good performance in H264 and MPEG2 codec distortions with the three databases comparing with other models.     

基于全零模块检测的H.264/AVC快速帧内模式选择算法*

H.264/AVC采用多方向、多划分的帧内预测模式,与其他视频编码标准相比具有更高的编码效率,但同时也使计算复杂度明显提升。通过分析各编码模式的特点和最佳模式分布规律,提出了基于全零模块检测的快速帧内模式选择算法,略过不可能进一步降低率失真代价的帧内预测模式,以降低编码过程的计算复杂度。实验结果表明,在保证编码性能的前提下,可以有效地降低H.264/AVC的计算复杂度。     

H.264/AVC解码芯片验证系统及验证策略

H.264/AVC视频编码标准是目前应用广泛的视频压缩标准,具有压缩比高、算法复杂等特点,给视频解码系统的设计和验证带来了挑战。文中基于一款H.264/AVC解码芯片架构,针对H.264/AVC视频解码系统的复杂性,构建了验证系统,提出多形式、分层次的验证策略,在解码芯片设计实现的各个阶段实施验证。根据RTL虚拟仿真、FPGA原型和后仿真等验证手段的特点,分别规划不同阶段的测试激励,形成基于H.264/AVC解码芯片的验证项策划,对类似H.264/AVC解码器的验证工作具有一定的帮助。     

Dyadic spatial resolution reduction transcoding for H.264/AVC

In this paper, we examine spatial resolution downscaling transcoding for H.264/AVC video coding. A number of advanced coding tools limit the applicability of techniques, which were developed for previous video coding standards. We present a spatial resolution reduction transcoding architecture for H.264/AVC, which extends open-loop transcoding with a low-complexity compensation technique in the reduced-resolution domain. The proposed architecture tackles the problems in H.264/AVC and avoids visual artifacts in the transcoded sequence, while keeping complexity significantly lower than more traditional cascaded decoder–encoder architectures. The refinement step of the proposed architecture can be used to further improve rate-distortion performance, at the cost of additional complexity. In this way, a dynamic-complexity transcoder is rendered possible. We present a thorough investigation of the problems related to motion and residual data mapping, leading to a transcoding solution resulting in fully compliant reduced-size H.264/AVC bitstreams.     

HEVC optimization based on human perception for real-time environments

High-Efficiency Video Coding (HEVC) is the new emerging video coding standard of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). The HEVC standard provides a significant improvement in compression efficiency in comparison with existing standards such as H264/AVC by means of greater complexity. In this paper we will examine several HEVC optimizations based on image analysis to reduce its huge CPU, resource and memory expensive encoding process. The proposed algorithms optimize the HEVC quad-tree partitioning procedure, intra/inter prediction and mode decision by means of H264-based methods and spatial and temporal homogeneity analysis which is directly applied to the original video. The validation process of these approaches was conducted by taking into account the human visual system (HVS). The adopted solution makes it possible to perform HEVC real time encoding for HD sequences on a low cost processor with negligible quality loss. Moreover, the frames pre-processing leverages the logic units and embedded hardware available on an Intel GPU, so the execution time of these stages are negligible for the encoding processor.

     

Performance Comparison of AVS and H.264/AVC Video Coding Standards

A new audio and video compression standard of China,known as advanced Audio Video coding Standard （AVS）.is emerging.This standard provides a technical solution for many applications within the information industry such as digital broadcast,high-density laser—digital storage media,and so on.The basic part of AVS,AVS1-P2,targets standard definition （SD）and high definition（HD）format video compression,and aims to achieve similar coding efficiency as H.264/AVC but with lower computational complexity.In this paper,we first briefly describe the major coding tools in AVS1-P2,and then perform the coding efficiency comparison between AVS1-P2 Jizhun profile and H.264/AVC main profile.The experimental results show that the AVS1-P2 Jizhun profile has an average of 2.96% efficiency loss relative to H.264/AVC main profile in terms of bit-rate saving on HD progressive-scan sequences,and an average of 28.52% coding loss on interlace-scan sequences.Nevertheless,AVS1-P2 possesses a valuable feature of lower computational complexity.     

一种H.264帧内预测模式的快速选择算法

H.264/AVC视频编码标准采用码率—失真度最优化(RDO)算法,以保证更高的压缩效率和更好的图像质量,但同时也大大增加了编码器的复杂度和运算负担。本文提出了一种新型的帧内预测模式的快速选择算法,该算法基于图像内部信息的变化剧烈程度进行判断,并通过方向矢量来减少候选帧内预测模式。试验结果表明,该算法可以将整个编码时间减少到原来采用RDO算法时的40%~50%,而且和RDO算法比较,最终压缩后的视频图像质量基本没有下降。