MPEG-4自然视频编码技术

对MPEG－4自然视频编码的关键技术作了详细的分析和阐述。首先介绍MPEG－4频语法结构，并对视频编码的框架概要分析。接着分析了自然视频编码中涉及到的关键技术，包括：VOP的产生；二值和灰度级α平面的编码技术；运动估计和补偿方法；纹理编码；基于对象的时间分级和空间分级；MPEG－4提供的再同步和各种错误掩盖，刷新方法，精 编码技术和零树小波基的静止图像编码技术。指出MPEG－4和MPEG－1，MPEG－2等标准的异同，突出MPEG－4的三个主要特点。最后给出MPEG－4技术在网络视频传输中的应用，并给出测试和分析。     

一种用于MPEG-4形状编码的快速运动估计算法

该文提出了一种用于MPEG-4形状编码的快速运动估计算法。该算法利用了形状编码及形状信息的固有特性,即基于上下文的运动估计特性、相邻二值alpha块的运动矢量相关性以及形状信息的二值特性。模拟结果表明,该算法具有运算量少、处理速度快的特点,适用于MPEG-4形状编码的实时软件实现。     

一种新的MPEG-4二值形状空域可扩展编码算法

可扩展编码和形状编码技术是MPEG-4视频编码部分的两个关键技术。文章在分析视频图像二值形状信息特点的基础上．提出了一种新的MPEG—4二值形状空域可扩展编码算法。试验结果表明这种算法编解码简单，速度快．码率较小。     

MPEG-4编解码算法及其视频性能分析

3G移动终端要求能够提供包含语音、数据和图像的多媒体业务，为此3GPP制定了第一个适合3G系统的基于电路交换的多媒体终端模型——3G-324M规范，该模型支持MPEG-4视频处理，它具有高压缩比和容错编码特性。在研究MPEG-4编解码算法基础上进行了MPEG-4视频编码的性能测试。     

MPEG-4视频标准及其关键算法

MPEG-4引入了视频对象的概念,有效地支持基于内容的图像编码,对不同的视频源标准格式和不同的视频码率提供有效的编码,以满足众多多媒体的应用需求。本文系统地分析了MPEG-4视频编码算法,对MPEG-4视频标准的关键概念进行了详细的解释。     

MPEG-2到MPEG-4视频转编码中的快速运动矢量重估算法

本文讨论了MPEG-2到MPEG-4视频转编码问题，提出了两种快速运动矢量重估算法，分别基于空域和时域。我们的算法利用已有运动信息和DCT变换的直流系数进行运动估计，可明显减少运算量，提高编码速度，并获得了与全搜索算法接近的图像质量，可满足网络视频传输的实时要求。     

MPEG-4的主要技术概览

简要介绍了MPEG-4标准的主要内容，在此基础上着重介绍了音频对象的编码和视频对象的编码。     

Subjective evaluation of MPEG-4 video codec proposals: Methodological approach and test procedures

A new audio-visual coding standard, MPEG-4, is currently under development. MPEG-4 will address not only compression, but also completely new audio-video coding functionalities related to content-based interactivity and universal access. As part of the MPEG-4 standardization process, in November, 1995 assessments were performed on technologies proposed for incorporation in the standard. These assessments included formal subjective tests, as well as expert panel evaluations. This paper describes the MPEG-4 video formal subjective tests. Since MPEG-4 addresses new coding functionalities, and also operates at bit-rates lower than ever subjectively tested before on a large scale, standard ITU test methods were not directly applicable. These methods had to be adapted, and even new test methods devised, for the MPEG-4 video subjective tests. We describe here the test methods used in the MPEG-4 video subjective tests, how the tests were carried out, and how the test results were interpreted. We also evaluate the successes and shortcomings of the MPEG-4 video subjective tests, and suggest possible improvements for future tests. The MPEG-4 video subjective tests were successful, providing the MPEG community with critical information to guide in the selection of technologies for inclusion in the video part of the MPEG-4 standard.     

MPEG-4视频流量多重分形建模

从多重分形树的定义出发，分析了多重分形各尺度系数的边缘分布特性及系数间自相关函数的关系，并利用得到的结论提出了一种新的MPEG-4视频流量多重分形模型（PMFM，predictable MFM）。通过对最粗尺度系数进行auto-regressive短相关预测建模，该模型具有了传统多重分形模型不具备的流量预测能力；另外，模型改进了各尺度乘子的参数获取方式，使得多重分形模型的稳定性有了显著提高。     

Automatic segmentation of video object planes in MPEG-4 based on spatio-temporal information

Segmentation of semantic Video Object Planes (VOP‘s) from video sequence is a key to the standard MPEG-4 with content-based video coding. In this paper, the approach of automatic Segmentation of VOP‘s Based on Spatio-Temporal Information (SBSTI) is proposed. The proceeding results demonstrate the good performance of the algorithm.     

MPEG-4形状编码器二进制运动估计的VLSI结构设计

阐明了所设计的二进制运动估计的VLSI硬件结构.首先介绍了MPEG-4形状编码中BME的基本原理,以及前人设计的一种DDBME结构;接着分析指出DDBME在利用数据冗余方面的缺陷,并给出了一种改进的运动估计结构,通过扩大PE阵列以及重新安排数据的分发机制,可以达到75%的数据利用率.硬件仿真结果与软件运行结果的对比表明了本设计的正确性,综合结果也说明了本设计可以在最低5.93 MHz的频率下满足MPEG-4 Core Profile & Level2的实时编码,可用于MPEG-4的VLSI实现.     

MPEG-2编码芯片中运动估计电路的设计

运动估计是视频压缩中最重要的环节，文章讨论了运动估计的基本原理并分析了其特点，采用了三步分层搜索算法．设计了一种基于MPEG-2的主档次标准的9PE全并行结构的高速运动估计电路，并通过FPGA验证，系统时钟频率达到35MHz，性能达到了实时编码的要求。     

基于MPEG-4的视频压缩系统的设计

所设计的视频压缩系统是基于MPEG-4的压缩标准进行设计的。可同时完成两路MPEG-4视频压缩，系统支持视频图像实时预览，视频由它直接传送到显存，压缩的码流也由它直接传送到内存，无需主机CPU介入做任何操作，并通过PCI接口传送到内存中，不占用CPU资源。特别适用于数字视频录像机、远程数字监控、网络视频应用等领域。     

MPEG-4视频编码器象素压缩模块的VLSI结构设计

文章设计了一种基于MPEG-4的视频压缩编码器中象素压缩模块的VLSI结构。该设计采用分布算式结构——NEDA作为DCT变换的核心技术；应用基于LUT表结构使量化／反量化模块的设计简洁明了；同时对AC／DC预测模块还应用了新的存储策略，大大降低了FPGA中宝贵的存储空间。在满足处理速度和精度的要求下，利用了较少的晶体管数目和简洁的结构实现了象素压缩模块。     

Motion compensation for very low bit-rate video

A combination of spatial transformation and image segmentation is used to compensate for non-uniform intensity changes in moving scenes. The method efficiently tracks movements such that the motion vectors alone can be employed to represent a moving object with complex motion. Using fast transformation and interpolation algorithms, it is shown that while the compression efficiency of the presented method is far superior to that of the conventional full search block-matching motion estimation, its computational complexity is still affordable.     

MPEG-4视频验证模型中基于内容的编解码算法

ＭＰＥＧ－４是一个正在制定的编码标准,除了具有 ＭＰＥＧ－１和 ＭＰＥＧ－２标准的基于“帧”的功能以外,ＭＰＥＧ－４视频编码算法还支持多媒体环境中对视频景物内的“物体”进行存取与操纵。文中描述了第四版ＭＰＥＧ－４视频验证模型的结构及其提供的主要编码工具和算法。     

MPEG-4中的视频误码复原方法

介绍了MPEG-4标准采用的几种视频编码纠错方法，并通过测试数据说明了它们的优点。用这些方法使得压缩的视频数据能够在无线信道中有效地传输。     

MPEG-4 video verification model: A video encoding/decoding algorithm based on content representation

MPEG-4 video aims at providing standardized core technologies allowing efficient storage, transmission and manipulation of video data in multimedia environments. This is a challenging task given the broad spectrum of requirements and applications in multimedia. In order to achieve this broad goal, rather than a solution for a narrow set of applications, functionalities common to clusters of applications are under consideration. Therefore, video group activities in MPEG-4 aim at providing solutions in the form of tools and algorithms enabling functionalities such as efficient compression, object scalability, spatial and temporal scalability, and error resilience. The standardized MPEG-4 video will provide a toolbox containing tools and algorithms bringing solutions to the above-mentioned functionalities and more.

The current focus of the MPEG-4 video group is the development of the Video Verification Models. A Verification Model (VM) is a common platform with a precise definition of encoding and decoding algorithms which can be presented as tools addressing specific functionalities. It evolves through time by means of core experiments. New algorithms/tools are added to the VM and old algorithms/tools are replaced in the VM by successful core experiments. Until October 1996, the MPEG-4 video group has focused its efforts on a single VM which has gradually evolved from version 1.0 to version 4.0, and in the process has addressed increasing number of desired functionalities, namely, content based object and temporal scalabilities, spatial scalability, error resilience, and compression efficiency.

This paper gives an overview of version 4.0 of the Video VM in MPEG-4. In doing so, issues, algorithms, and majors tools used in the development of this future video standard are discussed.     

一种简单的实时MPEG-4图像业务模型

提出了一种新的MPEG-4业务模型，它利用MPEG-4的帧结构特点，以IBB和PBB序列为基本处理单元，通过Hadamard变换在正交变换域对IBB和PBB序列间的相关性进行匹配建模，从而实现对MPEG-4图像数据短期相关和长期相关特性的精确捕获。仿真研究表明，用该模型产生的随机数据和实际MPEG4图像数据在概率密度函数和自相关函数上高度吻合，在以它们为输入源的漏桶评估实验中，二者对缓存要求和比特丢失率的估计也基本相同。该模型还具有所需参数少，模型简单效率高等优点，非常适合作为无线资源管理和系统级性能评估研究等的图像数据源模型。     

一种快速高效MPEG-4运动估计硬件结构的研究和实现

提出一种高度并行和多流水线处理的硬件结构,实现MPEG-4视频部分的全搜索块匹配运动估计算法.该硬件结构能实时地通过全搜索块匹配运动估计算法来搜索每个像素块最佳匹配运动向量,具有计算速度高、运动向量准确、较少的内置存储器要求、低运行时钟和低功耗等诸多优点,从而可满足移动视频业务和高清晰视频业务的需求.该硬件结构基于富士通的CE66库实现.