多媒体编辑器OpernEditor及其声音服务器的设计和…

ＯｐｅｎＥｄｉｔｏｒ是一个运行于分布式环境下的面向对象的多媒体编辑器，它具有易使用性、灵活性、支持增量式开发和网络分布等特点。为了便于把声音处理功能增加到其它多媒体应用中，把ＯｐｅｎＥｄｉｔｏｒ设计成一基于Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ模型的声音服务器。本文首先概述ＯｐｅｎＥｄｉｔｏｒ的功能和结构，然后详细讨论了ＯｐｅｎＥｄｉｔｏｒ中声音编辑处理功能及声音服务器的设计和实现技术。     

视景仿真编辑器ViewEditor的设计与实现

我们开发的ＶｉｅｗＥｄｉｔｏｒ是一个基于ＷｉｎｄｏｗｓＮＴ系统的视景仿真编辑器。它集图形、图象、声音、文字编辑于一体，支持开放式接口，具有界面优良、操作直观灵活。满足ＷＹＳＩＷＹＣ等特点。该文首先介绍了ＶｉｅｗＥｄｉｔｏｒ的功能和系统构成，然后对ＶｉｅｗＥｄｉｔｏｒ的层次模型与界面设计进行了详细的论述。     

OpenBASE的全局字典和数据库结构的设计与实现

本文介绍了面向多媒体应用的扩展关系型数据库ＯｐｅｎＢＡＳＥ中面向对象的数据字典设计与实现方法，即如何采用向对象的分析与设计方法进行数据字典中类的划分和类层次的构造，并介绍了基于这种字典结构的数据库整体结构。     

Open VMS AXP1.5版

Ｏｐｅｎ ＶＭＳ ＡＸＰ１．５版新增的能力包括：多种ＶＭＳ群集配置，支持对称多处理，ＤＥＣｄｔｍ服务以及加强型批／打印服务。Ｏｐｅｎ ＶＭＳ ＶＡＸ和Ｏｐｅｎ ＶＭＳ ＡＸＰ系统现在能并存于群集配置中，从而提供优越的投资保障。     

利用ToolBook实现动画,声音的同步播放与控制

该文介绍通过利用ＴｏｏｌＢｏｏｋ的ＴＢＫＭＣＩ函数和ＯｐｅｎＳｃｒｉｐｔ语言编写多媒体脚本程序，实现对动画，声音的同步播放与即时控制的方法，这种方法在作者开发的多媒体ＣＡＩ软件－“工程制图”中获得了满意的效果。     

多媒体会议系统MCONF的共享显示原理

共享应用程序是多媒体电子会议系统中的一类重要的应用程序，它为会议系统中不同节点的用户提供了一种交互手段。本文的前半部分介绍了多媒体电子会议系统的发展和作者所在的课题小组所完成的多媒体会议系统（ＭＣＯＮＦ）的概况，然后介绍了一个共享应用程序：基于字符编辑的共享文本编辑（ＳｈａｒｉｎｇＥｄｉｔｏｒ）设计方案和实现技术     

ODBC及Oracle SQL* NET在C/S中的配置与应用

一、引言ＯＤＢＣ（ＯｐｅｎＤａｔａＢａｓｅＣｏｎｎｅｃｔｉｖｉｔｙ开放数据库互联）允许数据库与应用程序实现数据交换,以及对不同ＤＢＭＳ的共享。ＳＱＬ＊ＮＥＴ是Ｏｒａｃｌｅ公司的远程数据库访问软件包,在网络环境下实现客户机／服务器的连接与通信。在目前较为流行和成熟的Ｃ／Ｓ解决方案中,如何使用ＯＤＢＣ及ＳＱＬ＊ＮＥＴ来访问Ｏｒａｃｌｅ数据库服务器,是此类开发中常遇到的关键问题之一。本文分别针对Ｕ－ＮＩＸ、ＮｅｔＷａｒｅ两种系统环境,对上述问题作一介绍。二、ＳＱＬ＊ＮＥＴ的结构及功能ＳＱＬ＊ＮＥＴ采用…     

多媒体CAI网络教室的软件实现

本文着重讨论在不改变原有硬件设备的前提下，从软件方面来实现多媒体ＣＡＩ网络教室的基本功能：屏幕控制功能；声音、图像、视频信号的传送；电子白板功能；讨论、交谈功能。这些功能的“软实现”仅须在ＷＩＮＤＯＷＳＮＴ为服务器、ＷＩＮＤＯＷＳ９５为客户端的网络环境中，在ＩＬＳ的支持下便可实现，基本满足日常进行多媒体ＣＡＩ教学的需求。     

OpenServer5开发系统

本文对新一代的服务器操作系统ＳＣＯ ＯｐｅｎＳｅｒｖｅｒ５的主要特征，特别是它的开发系统作概要介绍。新的编译器、可视化开发环境、系统追踪功能、兼容性移植性等，都是这个开发系统值得称道的地方。     

通用图片解说库系统的设计开发

利用ＭｉｃｒｏｓｏｆｔＷｉｎｄｏｗｓ的对象连接与嵌入ＯＬＥ（ＯｂｊｅｃｔＬｉｎｋｉｎｇａｎｄＥｍｂｅｄ－ｄｉｎｇ）技术，集成Ｗｉｎｄｏｗｓ的ＯＬＥ软件的多媒体处理功能，开发图文声并茂的图片解说数据库系统。     

AN OBJECT-ORIENTED DISTRIBUTED MULTIMEDIA EDITOR

ＡＮＯＢＪＥＣＴ－ＯＲＩＥＮＴＥＤＤＩＳＴＲＩＢＵＴＥＤＭＵＬＴＩＭＥＤＩＡＥＤＩＴＯＲ￥ＸｕＤａｎ（ＣｏｍｐｕｔｅｒＳｃｉｅｎｃｅＤｅｐａｒｔｍｅｎｔＹｕｎｎａｎＵｎｉｖｅｒｓｉｔｙＫｕｎｍｉｎｇ，ＹｕｎｎａｎＰｒｏｖｉｎｃｅ，６５００９１Ｐ．Ｒ．...     

X终端音频文件系统映射设计

Linux操作系统下的X—Windows系统仅能实现终端机上的远程图形用户界面，而不能实现声音在终端机上的远程播放，直接限制了X终端的多媒体表达能力。利用虚拟设备机制和远程映射机制，让服务器端用户进程在运行过程中的音频数据映射到服务器端编制的虚拟音频设备上，虚拟音频设备软件截取相关数据后，透过网络发送到对应的X终端，X终端机再利用相关软件映射到本地音频设备进行媒体再现。该模式实现了音频设备的远程映射，使得多媒体播放更加流畅，X终端应用更加广泛。     

基于感知质量的多媒体会议系统的软件实现

论述了多媒体视频会议系统中多点控制单元(MCU)服务器、客户端的软件设计及实现。在客户端设计中,引入了基于用户感知质量的播放缓存算法,以提高动态网络环境下多媒体会议的音频性能。     

A generic content-based image retrieval framework for mobile devices

Multimedia mobile devices have created new possibilities for developing and accessing a variety of multimedia items such as images, audio and video clips. Personal multimedia items are, nowadays, being consumed at an enormous rate. Therefore, the management of these media items has become a pressing problem. In this paper, a client-server content-based image retrieval framework for mobile platforms is developed, which provides the capability of content-based query and browsing from mobile devices. The proposed framework provides an adaptive user interface and a generic structure, which supports a wide range of mobile devices. In this framework, a client requests the server for retrieval of particular images with a particular content. The server performs a content-based retrieval of images from a selected database and streams the retrieved results back to the client in an efficient way. The query results are transmitted over a wireless network and a certain number of similar images are rendered on the mobile device screen using thumbnail sizes. The proposed framework serves as a basis of content-based image retrieval on mobile devices. It addresses several important challenges such as hardware and software limitations as well as efficient use of the available network bandwidth.     

Synchronized delivery and playout of distributed stored multimedia streams

Multimedia streams such as audio and video impose tight temporal constraints for their presentation. Often, related multimedia streams, such as audio and video, must be presented in a synchronized way. We introduce a novel scheme to ensure the continuous and synchronous delivery of distributed stored multimedia streams across a communications network. We propose a new protocol for synchronized playback and compute the buffer required to achieve both, the continuity within a single substream and the synchronization between related substreams. The scheme is very general and does not require synchronized clocks. Using a resynchronization protocol based on buffer level control, the scheme is able to cope with server drop-outs and clock drift. The synchronization scheme has been implemented and the paper concludes with our experimental results.     

“互联网+”时代多媒体教室 维护创新模式研究

随着互联网、传感器、多媒体等技术的快速发展,许多学校构建了现代化的多媒体教室,利用先进的网络拓扑 架构将音响、麦克风、投影仪、服务器、显示器等设备集成在一起。多媒体教室的运行将会产生不兼容、效率低、音响输出不正 常等软硬件资源问题。传统的被动维护模式影响多媒体教室正常使用,亟需利用传感器、视频监控和数据挖掘等技术构建新 型多媒体教室维护创新模式,实施主动型的运行维护模式,提高多媒体教室建设和维护的成效。     

分布式多媒体系统中的媒体同步

本文介绍分布式多媒体系统中的媒体同步问题，着重介绍了基于MPEG－I的分布式多媒体系统中，视频和音频的同步以及媒体服务器和客户之间的流同步。     

基于RTMP的流媒体服务器的研究

多媒体数据要在网络上传输,必须先对多媒体数据进行流化处理。要想流化多媒体数据,就需要流媒体服务器。所以流媒体服务器对多媒体数据的传输有着至关重要作用。其中流化处理就是对多媒体数据进行封装,把音视频数据打包成能进行流传输的数据包。而且提高流媒体服务器的性能一个有效途径是提高缓存的利用率,使系统为更多的媒体流服务。文章以RTMP为基础,首先分析了该传输协议,并提出了一种改进的缓存策略,使流媒体服务器性能有了提高。     

Real-Time Multimedia Applications in a Web-Based Robotic Telecare System

In this paper, real-time multimedia applications are integrated into a Web-based robotic telecare system. Using Java media framework (JMF), a video/audio conference system is developed to improve the interaction among caregivers, and switches remote robot manipulating privilege with the help of a centralized management server. This video/audio conference system is established on a similar profile of H.323 multipoint control unit (MCU). Access control is utilized to guarantee confidentiality of telecare users. Different telecare services are provided to meet requirements of various users. The whole telecare system is verified in a campus network.     

A client-driven media synchronization mechanism for RTP packet-based video streaming

Media synchronization is used to correctly playback a video stream with its associated audio. To support synchronization between video and audio streams transported over IP networks, an RTP/RTCP protocol suite is usually employed. In conventional server-driven media synchronization, the server needs to periodically transmit an RTCP sender report (SR) packet to provide the client with a UTC time in NTP format corresponding to the RTP timestamp carried by each RTP packet. In this paper, we propose a precise client-driven media synchronization mechanism for an RTP packet-based multimedia streaming service. In the proposed method, the server does not need to send any RTCP SR packets for synchronization. Instead, the client device derives the precise normal play time (NPT) for each video and audio stream from the received RTP packets containing an RTP timestamp. Simulations show that the proposed client-driven synchronization method can provide accurate media synchronization without employing an RTCP SR packet and accordingly reduce the initial synchronization delay, the processing complexity at the client device, the number of required user datagram protocol ports, and the amount of control traffic injected into the network.