基于MPEG-4的主从式多媒体网络教学系统设计

多媒体网络教学技术作为一种前沿现代教育技术受到广泛的重视。系统结合多媒体网络教学应用的教学需求与特点，采用MPEG-4压缩标准建立了一个基于校园网的虚拟的教学环境，在这个环境中可以实现教师备课、现场实时授课、学生自主点播课件、师生课后交流、答疑、批改作业以及考试等教学环节。重点介绍了基于MPEG-4的多媒体网络教学系统的体系结构及采用的主要技术。     

Applying and implementing the MPEG-4 multimedia standard

MPEG-4's many algorithms and high-performance requirements pose a challenge for designers of a new generation of flexible, low-power coder/decoder VLSI implementations for mobile and portable applications. In addition to introducing MPEG4, this article looks at how the standard will enhance existing applications and enable new ones, and then discusses the ongoing effort to design an optimized MPEG-4 processor platform     

Delivery of medical multimedia contents through the TCP/IP network using RealSystem

We developed a low cost, user-friendly multimedia delivery system, to provide medical lectures saved as multimedia contents to persons engaged in medicine. This system was created using the RealSystem package with the TCP/IP network. Users can review lectures and medical meeting presentations with video and audio through the Internet, whenever convenient. Each medical source of video and slide has been clearly displayed on a screen. Members of medical associations or medical students can easily review the most interesting parts of these files. This system is being used efficiently in distance learning and aids the diffusion of the latest information and technology to busy physicians and medical students.     

Real-time interactive MPEG-4 system encoder using a cluster ofworkstations

MPEG-4 currently being finalized by the Moving Pictures Experts Group of the ISO is a multimedia standard, MPEG-4 aims to support content-based coding of audio, text, image, and video (synthetic and natural) data, multiplexing of coded data, as well as composition and representation of audiovisual scenes. One of the most critical components of an MPEG-4 environment is the system encoder. An MPEG-4 scene may contain several audio and video objects, images, and text, each of which must be encoded individually and then multiplexed to form the system bitstream. Due to its flexible features, object-based nature, and provision for user interaction, MPEG-4 encoder is highly suitable for a software-based implementation. A full-scale software-based MPEG-J system encoder with real-time encoding speed is a nontrivial task and requires massive computation. We have built such an encoder using a cluster of workstations collectively working as a virtual parallel machine. Parallel processing of MPEG-4 encoder needs to be carried out carefully as objects may appear or disappear dynamically in a scene. In addition, objects may be synchronized with each other. User interactions may also prohibit a straightforward parallelization. We propose a modeling methodology that captures the spatio-temporal relationship between various objects and user interaction. We then propose a number of scheduling algorithms that periodically allocate MPEG-4 objects to multiple workstations ensuring load balancing and synchronization requirements among multiple objects. Each scheduling algorithm has its own performance and complexity characteristics. The experimental results, while showing real-time encoding rates, exhibit tradeoffs between load balancing, scheduling overhead cost, and global performance     

基于MPEG-4关键技术的视频医疗系统

通过对MPEG-4视频编码关键技术及原理的分析,利用MPEG-4视频技术实时、高效无线视频传输的特性,开发、设计并实现了基于JMF技术、应用于智能化社区的视频医疗系统。在视频医疗系统中,由JMF提供一个统一的架构和通信协议来管理基于时间媒体的获取、处理和传输。采用实时传输协议/实时传输控制协议(RTP/RTCP)很好的保证了视频传输过程中的实时性,并在JMF中引入了MPEG-4压缩算法插件进行视频压缩。MPEG-4压缩算法压缩比高,并且具有良好的网络适应性。     

An open framework for a multimedia medical document system (a multimedia document system framework)

A novel and generalized open framework for multimedia information manipulation is proposed. The document system consists of functional modules for capturing, storing and presenting multimedia data. These modules work independently and communicate through aHyperDocument Interfacelayer. The modular approach has the added advantage of easy-to-maintain and the convenience for future enhancements. Hypermedia and temporal –spatial relationships between document media nodes are embedded into the data structure to support flexible presentation of multimedia information. Windows and a specially designedDocument Tree Dialogprovide an environment for efficient and user-friendly information retrieval. Other system issues such as security and customization are also addressed in the design. Based on this approach, a medical multimedia document system to handle cardiac catheterization record (CCR) was designed as a demonstration for the research idea. The proposed design can be applied and extended to cover a variety of multimedia applications.     

A study of multimedia annotation of Web-based materials

Web-based learning has become an important way to enhance learning and teaching, offering many learning opportunities. A limitation of current Web-based learning is the restricted ability of students to personalize and annotate the learning materials. Providing personalized tools and analyzing some types of learning behavior, such as students’ annotation, has attracted attention as a means to enhance Web-based learning. We describe a Web-based tool for creating and sharing annotations and investigate the effect on learning of its use with college students. First, an annotation tool was designed and implemented for the research. Second, learning support mechanisms, including full and group annotation sharing, were developed to promote students’ motivation for annotation. Lastly, experiments with individual and shared annotation were conducted and the results show that the influence of annotation on learning performance becomes stronger with the use of sharing mechanisms. We conclude that there is value in further study of collaborative learning through shared annotation.     

Web-based synchronized multimedia lecture system design for teaching/learning Chinese as second language

In the past decade, the use of computer technology for language instruction has expanded rapidly. In Taiwan, overseas students whose native languages are not Chinese mostly get trouble in learning and communicating particularly during the first year of their study. To overcome their language barrier in National Chi Nan University (NCNU), a Web-based Chinese classroom (http://chinese.csie.ncnu.edu.tw) exploiting advanced Web and multimedia technologies has been initiated since 2002. This paper presents the core developments of the Web-based Synchronized Multimedia Lecture (WSML) system for fulfilling language learning requirements on listening, speaking, reading and writing. It facilitates students in Chinese comprehension self-learning on the Web and can easily be customized for different foreign language learning. Technical issues are addressed from two perspectives to meet the pedagogical approaches of teaching and learning foreign languages: (1) the synchronized multimedia tutoring and the exercise practice functions for students, and (2) the multimedia lecture authoring and the exercise management tools for teachers.     

基于RTP的MPEG-4视频监控系统的设计

简述了MPEG-4标准的特性和RTP/RTCP协议的概念,详细说明了将MPEG-4码流映射到RTP净荷的方法,最后在此基础上提出了一种基于网络的远程视频监控系统的设计方案.该方案首先给出了系统的设计框架,然后分别阐述了发送端和接收端的具体实现流程.实验结果表明,采用RTP/RTCP协议传输MPEG-4码流能有效利用网络带宽,并且图像质量有较大的提高.     

基于多DSP的MPEG-4系统的设计

基于MPEG-4的视频编解码技术已经成为当前多媒体技术发展的热点。本文提出了一种以多DSP为核心的MPEG-4编解码系统,并设计出了具体的硬件平台方案。     

嵌入式Linux系统下MPEG-4专用编码器驱动设计

嵌入式视频监控的方案设计已有众多论述,但针对实现过程中Linux下视频MPEG-4编码的驱动设计鲜有提及.本文以视频编码芯片IME6410的驱动设计为实例,主要论述了基于Video for Linux(V4L)规范的视频驱动实现方法,包括硬件接口、设备初始化、文件操作实现等,并着重分析了V4L规范、视频驱动及内核之间的内在联系.     

基于多DSP的MPEG-4系统的设计

基于MPEG-4的视频编解码技术已经成为当前多媒体技术发展的热点.本文提出了一种以多DSP为核心的MPEG-4编解码系统,并设计出了具体的硬件平台方案.     

Web-based SBLR method of multimedia tools for computer-aided drawing

Multimedia Tools and Applications - As one of the most successful multimedia tools for digital media and creative industry, computer-aided drawing system assists users to convert the input real...     

MPEG-4流媒体系统中的视音频同步

流媒体系统中视音频同步是非常重要的。首先简要地介绍了MPEG 4的相关概念,分析了流媒体系统中影响视音频同步的因素,提出了一套相应的解决方案,最后,给出了一个基于MPEG 4的视频监控系统的实现。     

Towards an ontology based framework for searching multimedia contents on the web

Multimedia Tools and Applications - We live in a world where there are huge number of consumers and producers of multimedia content. In this sea of information, finding the right content is like...     

基于H.323系统的MPEG-4视频传输

在H.323系统中采用视频压缩标准H.261和H.263,这两种协议存在着重建图像质量差、运动不连贯、编码效率低下等诸多问题.MPEG-4是国际上性能优越的视频编解码标准,改善了低比特率压缩及提高了容错性,比以往标准(H.261和H.263)有着更出色的性能.对在H.323系统中MPEG-4视频传输进行了研究,实现了基于H.323系统的MPEG-4视频传输,给出了MPEG-4传输方案,并与H.263编码标准的结果进行了比较分析,得到了令人满意的结果.     

MPEG-4标准概述

MPEG-4是基于对象的编码标准，以其基于内容的交互性、高效的压缩性与通用的访问性等特点，被广泛的应用于电子、通信和计算机三大产业领域。文章概述了MPEG-4标准的结构特点及其应用。     

MPEG-4标准概述

MPEG-4是基于对象的编码标准,以其基于内容的交互性、高效的压缩性与通用的访问性等特点,被广泛的应用于电子、通信和计算机三大产业领域。文章概述了MPEG-4标准的结构特点及其应用。     

Dejittering in the transport of MPEG-2 and MPEG-4 video

When multimedia information is transported over a packet-switched network, the quality of presentation can be degraded due to network delay variation or jitter. This paper presents a dejittering scheme that can be used in the transport of MPEG-4 and MPEG-2 video to absorb any introduced network jitter, thus preserving the presentation quality of transported media streams. The dejittering scheme is based on the statistical approximation of delay variation in the arrival times of video packets carrying encoded clock reference values and a filtering and re-stamping mechanism. In addition, a brief overview of the MPEG-4 system is presented.