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本文介绍了利用VISUALFOXPRO的应用程序接口FOXTOOLS调用WINDOWS的DLL库开发多媒体播放器的原理及实现技术,利用该播放器可以对波形文件(.WAV),数字音乐,(.MID),视频图象(.AVI)动画(.FLA)音频,压缩视频(.MPG)V-CD视频,(.DAT)等进行控制和播放。 相似文献
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在专用网上实现的中西文兼容Videotex终端的设计任伟利(西安交通大学信息与控制工程系西安710049)DESIGNOFCOMPATIBLECHINESE-ENGLISHVIDEOTEXTERMINALBASEDONSPECIAL-PURPOSEN... 相似文献
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SDRAM,SSRAM对于平衡存储器和CPU的带宽,实现主存的猝发访问,提高系统性能价格比有重要意义,本文基于Pentium处理器,讨论了高速缓存和主存采用SSRAM,SDRAM的不同系统实现方法及相对性能,不同的系统实现就是在性能,价格和设计复杂性之间的取舍,此分析同样适用于任何嵌入式一级高速缓存的处
处理器。 相似文献
处理器。 相似文献
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本文针对ITU G.728标准语音编解码器,提出了一种DSP的实现方法。在简介G.728编解码和DSP芯片TMS320C541基础上,本文主要研究了CELP(LD-CELP)算法在TMS320C541上的实现和实现此算法的一些关键技术,并给出了实际仿真结果。 相似文献
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DWMT系统在TMS320C80上的仿真实现 总被引:1,自引:0,他引:1
基于小波变换的离散多音传输系统(DWMT系统)是一种抗干扰能力强的高效数据传输系统,其主要在两种实现方案:(1)基于通用可编程DSP芯片的软件实现方案;(2)基于通用DSP芯片和专用VLSI芯片的软硬件结合方案。本文在分析了DWMT系统的实实现结构、运算量以及滤波器优化方法等基础上,利用TMS320C80软件开发系统对基于通用DSP的软件实现方案进行了仿真,并且详细地介绍了该方案的软件流程以及一些 相似文献
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组播视频会议环境下的H.323接入网关的设计与实现 总被引:1,自引:0,他引:1
H.323[1]会议系统是基于单播的视频会议系统,多点会议通过多点控制单元(MultipointControlUnit,MCU[1])来进行。IP网络上另一类会议系统是基于组播(Multicast)的视频会议系统,通过组播机制实现多点通信。该文提出的H.323终端接入网关MCU-M(MultipointControlUnitforMulticast)使组播视频会议环境支持基于H.323协议的呼叫接入,实现了这两类系统之间的互通,极大地扩展了组播视频会议环境的用户群。H.323终端接入网关原型还可以被进一步扩展为通用的信息互通平台,用来连接各种不同的多媒体终端。 相似文献
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H.323协议是ITU(国际电信联盟)制订的一套在分组网上提供多媒体通信的标准.MCU(多点控制单元)是H.323协议中提供多点会议的实体.介绍了MCU的功能,阐述了一种软件实现的集中式多点控制单元的系统架构,并讨论了多点处理的实现方法. 相似文献
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Current typical video conferencing connection is bridged by a multipoint control unit (MCU), which may cause large delay and communication bottleneck for the whole system. With the development of network technology, a video conferencing system can be implemented based on software-defined networking (SDN), which makes the service controllable and improves the scalability and flexibility. Additionally, a video encoding method called scalable video coding (SVC) can also help. In this paper, we propose a video conferencing architecture based on SDN-enabled SVC multicasting, which discards the traditional Internet group management protocol (IGMP) and MCU. The system implements SVC multicast streaming to satisfy different device capabilities of various conference terminals. The SDN controller is responsible for dynamically managing and controlling the layers of a video stream when a conference member faces network congestion. Also, a conference manager is designed to facilitate the management of the conference members. Experimental results show that our system can not only provide a flexible and controllable video delivery, but also reduce the network usage while guaranteeing the quality of service (QoS) of video conferencing. 相似文献
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In this paper, we propose a new approach to establishing application layer conference trees for multimedia multipoint conferences on the Internet using the Megaco/H.248 protocol, a Voice over IP (VoIP) media gateway control protocol. In existing VoIP protocols (and also legacy telephone networks), a multipoint conference takes place through an MCU, and forms a star topology centered at the MCU. This paper suggests to establishing shared, cost effective conference trees for VoIP conferences. Each tree is rooted at the conference initiator, who initiates the conference, and spans over all the conference members. Tree branches grow or are trimmed dynamically and adaptively, in a way to avoid the growth of a skewed tree. We develop a simplified analytical model and conduct simulations to evaluate the performance of the proposed approach. The results show that our approach enjoys the advantage of lower join latency and better bandwidth efficiency compared to the traditional MCU approach, and is cost effective compared to a near optimal Steiner tree. 相似文献
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Chan A.T.S. Jiannong Cao Chan C.K. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2005,35(6):811-830
WEBGOP is a programming architecture for collaborative Web services using graph-oriented programming. The motivation for the project comes from the realization that the integration of collaborative Web services lacks support. The aim of WEBGOP is to extend the Web from a client-server system to a structured multipoint system. A graph abstraction of the network provides the structure for the integration of Web services and facilitates their configuration and programming. Using WEBGOP, a logical graph representing a virtual-overlay network over the Internet is created to link up collaborative Web services. Web services are individually or jointly invoked through either unicast or multicast messages within the overlay network. All messages are based on the simple-object access protocol (SOAP). This forms an extension of the hypertext transfer protocol (HTTP) to support the distributed invocation of Web services. The Web services on different servers work collaboratively for a multipoint network application. This project provides a structured integration of Web services by extending the support of intermediary processing in a multipoint service. It also provides a rich network-programming interface for a new class of integrated Web applications while retaining the use of the Internet protocol and HTTP. 相似文献
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文章基于MPEGLayerIII码流的特点,在其解码过程中嵌入软件实现的10段图形均衡器。首先在PC机上仿真和定点化,然后在MPEGLayerIII的单片16位定点DSP程序中实现了该均衡器。实验结果表明文中设计的均衡器具有良好的音频品质。其算法简单易行,可同时应用于MP3解码软件和MP3播放器的均衡器设计。 相似文献
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介绍了采用IXP425作为核心主控单元和3片DM642作为核心数据处理单元的会议电视多点控制单元的硬件设计原理和实现方法。主控制器IXP425模块完成网络发送/接收、数据调度、PCI控制等功能。数据处理DM642模块完成音/视频混合与切换等功能。IXP425和DM642之间采用PCI总线连接,各模块之间数据传输速度快,提高了数据处理效率。 相似文献