多媒体框架标准MPEG-21

文章介绍MPEG-21多媒体框架标准的背景、目的、用户模型及用户需求，并进一步阐述MPEG-21的主要内客和关键技术，其中着重讲述数字项声明、数字项的识别与描述等重要技术。     

MPEG-7标准及其在多媒体信息中的应用

MPEG-7标准(多媒体内容描述接口)为各类多媒体信息提供一种标准化的描述,为日渐庞大的多媒体信息管理和迅速检索提供了许多方法和参考工具。介绍了MPEG-7的标准,阐述了MPEG-7的范围,应用等等。MPEG-7具有较强的灵活性、可扩展性,应用广泛,必将促进多媒体技术快速发展。     

对MPEG-7定义的理解及其在教育教学中的应用

当今各类多媒体信息正在世界范围内快速增长．越来越多的信息是以数字形式、在线形式以及诸如静止图像、图形、3D模型、声频、语音、视频等形式出现。MPEG-7标准（多媒体内容描述接口）将为各类多媒体信息提供一种标准化的描述,这种描述与内容本身有关,允许快速和有效地查询用户感兴趣味的资料。     

基于MPEG-21的多媒体适应性框架研究

为了满足人们对能够使用任何设备在任何时间、任何地点都能访问多媒体内容的要求,MEPG-21多媒体框架被提出.文章简要介绍了MPEG-21多媒体应用框架,之后提出了一个多媒体内容的适应性框架,最后对传输适应性多媒体内容的协议做了阐述.     

一种实现MPEG-7标准的基于内容的图像检索系统

图像检索技术中,描述和定义图像资料是关键任务之一,多媒体内容描述接口(MPEG-7)标准,能够以明确的格式结构和语法定义多媒体信息,这些描述与内容本身有关。在此基础上,给出了一种实现MPEG-7标准的图像检索系统的抽象模型,叙述了其中的关键技术。     

对MPEG-7定义的理解及其在教育教学中的应用

<正>当今各类多媒体信息正在世界范围内快速增长,越来越多的信息是以数字形式、在线形式以及诸如静止图像、图形、3D模型、声频、语音、视频等形式出现。MPEG-7标准(多媒体内容描述接口)将为各类多媒体信息提供一种标准化的描述,     

基于MPEG-4流媒体数据压缩与传输系统的分析与实现

MPEG-4流媒体数据压缩技术为网络多媒体信息的传送提供了一种有效的方法.文章介绍了MPEG-4流媒体数据压缩技术中的编码技术,并实现了基于RTP/RTCP协议的MPEG-4流媒体传输过程.     

基于MPEG-7的视频信息检索探析

基于内容的视频信息检索方法是针对传统视频信息检索方法的局限而提出的MPEG-7是描述多媒体信息内容的重要标准,利用MPEG-7描述视频结构可以促进视频信息内容的描述、获取和检索。而镜头分割和关键帧提取、特征抽取与标引、视频结构分析以及显示和交互技术是视频信息检索中关键技术。     

一种视频会议系统的研究与实现

介绍了使用局域网组播技术和Directshow多媒体开发框架实现多方视频会议系统的方法。系统引入了会议管理服务器以控制多媒体数据在网络中的接入和访问,使网络不会由于多媒体数据的激增而发生拥塞,从而保证服务质量。系统使用了面向对象的方法和UML语言,分析和设计了各个模块。系统的视频部分采用了MPEG-4编解码技术,音频数据留采用了G.729编解码方法。根据该设计方案,完成了该系统的设计和开发,实现了多人同时通讯的模拟视频会议功能。     

Authorware设计控制Flash动画

Authorware和Flash在平时的课件制作中应用都很广泛，Authorware是一种基于图标和流程线的多媒体创作平台，具有丰富的函数和程序控制功能。它允许用户使用文本、图形、图像、声音、动画和视频等多媒体信息来创作一个具有交互功能的多媒体应用程序。教师们也常会遇到在Authorware中调用Flash动画的情况，那么如何在Authorware中方便地控制Flash动画呢?     

SVC bitstream adaptation in MPEG-21 multimedia framework

INTRODUCTION Scalable video coding (SVC) (Schwarz et al., 2004) is the most promising video format for appli- cations of collaborative communication. First, SVC format, which is extended from the latest advanced video coding (AVC), is appropriate for creating a wide variety of bitrates with high compression effi- ciency. Second, an original SVC bitstream can be easily truncated in different ways to meet various characteristics and variations of devices and connec- tions. The scalabil…     

MPEG-4技术及其在远程教育中的应用

较详细地介绍MPEG—4的特点、标准与制作，采用MPEG—4方式的多媒体课件的制作以及MPEG—4在远程教育中的应用及前景。     

Delivering audiovisual content with MPEG-21-enabled cross-layer QoS adaptation

Future multimedia communication systems have to support the user‘s needs, the terminal capabilities, the content specification and the underlying networking technologies. The related protocols and applications must be designed from this integration perspective in a cross-layer centric manner. In this paper, we propose an implementation of a streaming service (e.g.,Television over IP service) with a unified QoS management concept that enables an IP driven integration of different system components (terminal, user, content, and network). The MPEG-21 framework is used to provide a common support for implementing and managing the end-to-end QoS. The main focus of this paper is on the architecture design, protocols specification and implementation evaluation. Performance evaluations using PSNR and SSIM objective video quality metrics show the benefit of the proposed MPEG-21-enabled cross-layer adaptation.     

MPEG-4的一种运动估计算法及其实现

MPEG系列标准是国际上影响最大的多媒体技术标准,其包含的技术很多,本文主要对一种新的块匹配运动估计算法一线性正方形搜索算法（LSS算法）以及硬件实现作了一些探讨。     

Resynchronization and remultiplexing for transcoding to H.264/AVC

H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content delivery, etc., it induces an immense demand for converting a large volume of existing multimedia content from other formats into the H.264/AVC format and vice versa. In this work, we study the remultiplexing and resynchronization issue within system coding after transcoding, aiming to sustain the management and time information destroyed in transcoding and enable synchronized decoding of decoder buffers over a wide range of retrieval or receipt conditions. Given the common intention of multiplexing and synchronization mechanism in system coding of different standards, this paper takes the most widely used MPEG-2 transport stream (TS) as an example, and presents a software system and the key technologies to solve the time stamp mapping and relevant buffer management. The solution reuses previous information contained in the input streams to remultiplex and resynchronize the output information with the regulatory coding and composition structure. Experimental results showed that our solutions efficiently preserve the performance in multimedia presentation.     

Dynamic multimedia stream adaptation and rate control for heterogeneous networks

Dynamic adaptation of multimedia content is seen as an important feature of next generation networks and pervasive systems enabling terminals and applications to adapt to changes in e.g. context, access network, and available Quality-of-Service (QoS) due to mobility of users, devices or sessions. We present the architecture of a multimedia stream adaptation service which enables communication between terminals having heterogeneous hardware and software capabilities and served by heterogeneous networks. The service runs on special content adaptation nodes which can be placed at any location within the network. The flexible structure of our architecture allows using a variety of different adaptation engines. A generic transcoding engine is used to change the codec of streams. An MPEG-21 Digital Item Adaptation (DIA) based transformation engine allows adjusting the data rate of scalable media streams. An intelligent decision-taking engine implements adaptive flow control which takes into account current network QoS parameters and congestion information. Measurements demonstrate the quality gains achieved through adaptive congestion control mechanisms under conditions typical for a heterogeneous network.     

基于MPEG-2非编系统精确到帧编辑的实现

MPEG-2的视频数据有自身的技术规范,基于MPEG-2的非线性编辑系统要实现精确到帧的编辑,必须采取相适应的算法来实现。本文从MPEG-2的技术层面入手,分析了精确到帧编辑的含义,并在一个具体的算法基础上重点对编辑过程中用得最常见的删除、插入操作的具体实现进行了分析。