【作者】 唐楚华；

【导师】 郭庆平；

【作者基本信息】 武汉理工大学 ， 计算机科学与技术， 2011， 硕士

【摘要】 目前视频会议已经在实用化方面取得了迅速的发展,并在军事、经济、文化等领域发挥了重要的作用,其功能也已由原先单纯的电视会议功能逐渐发展出远程教学系统、远程监控系统、远程医疗系统等多方面的综合业务。因此,视频会议技术势必将进入一个新的发展阶段。由ITU提出的H.323协议标准目前是视频会议中被普遍遵循的标准。相比于其他的一些标准,依据H.323协议标准实现的系统有更好的稳定性、互通性、经济性。首先本文研究了H.323协议标准和基于H.323协议的视频会议系统的体系结构,重点对系统中的协议栈、实体、通信过程、会议的控制和管理等模块进行了详细分析。然后对支持H.323协议的多点视频会议的openH.323协议库文件进行了分析,并对ITU-T H.323多点视频会议系统的相关模块进行了总体设计和详细设计。最后实现了一个可用的视频会议系统,该系统符合H.323协议标准,并能够实现局域网内会议终端之间的实时信令交互和数据传输。该系统采用集中式的体系结构,以C/S方式作为实现模型,为用户提供了完备、直观、便捷的实用功能和用户操作界面。在以上述方案实现基本的视音频会议系统的基础上,本文还对系统做了三个方面的改进：一是在系统中增加了动态密钥登陆模块。动态密钥登录实现的基本原理是在服务器端生成、分配密钥,在接收端收到密钥后,客户端凭借密钥登录系统,这样有效提高了视频会议系统的安全性。二是在系统中增加了加密通信模块。加密通信模块是基于RSA数据加密技术实现的,RSA让数据在系统中加密传输,从而进一步增强了系统中信息传递的安全性,聊天安全更有保障。另外,此模块还具有数字签名的作用,它实现了传递信息的防篡改、防抵赖以及客户端的身份认证等目的。三是在实现的系统中增加了手机短信收发模块。此模块是基于短信猫技术实现的,它对视频会议系统作了一个非常实用的功能扩展。此模块允许手机用户通过收发手机短信的方式加入到视频会议中来,极大地方便了用户。最后,总结了本文所做的工作,并对视频会议系统的未来发展进行了展望。更多还原

【Abstract】 Video conferencing has now made a rapid development in practical, and has played an important role in the military, economic, cultural and other fields, and its function has developed it from a original and simple video-conferencing capabilities to the progressive development of the distance education system, remote monitoring system, remote medical system, and many other integrated services. Therefore, the video conferencing technology is bounded to enter a new stage of development. Proposed by the ITU, the standard H.323 video conferencing is now a widely followed standard. Compared to some other standard, the achieved standard based on H.323 has better system stability, interoperability, and economy.First, this thesis studies the H.323 protocol standard and video conferencing system architecture based on H.323 protocol, focusing on analyzing protocol stack, physical, communication process, conference control and management modules in the system in detail. In the thesis, openH.323 protocol library files that support the H.323 protocol and multi-point video conferencing are analyzed, and the overall and detailed design is made that based on the related ITU-T H.323 multi-point video conferencing system modules. Finally, the project has implemented a available video conferencing system that meets the H.323 protocol standard, and is able to achieve real-time LAN signaling session interaction and data transmission between the terminal. The system adopts a centralized architecture and regard C/S model as the implementation model, to provide users with comprehensive, intuitive, convenient and practical features, and user interface.In the project, basic video and audio conferencing system is implemented, and the system has also made improvements in three areas:First, Dynamic Key Loging module is added in the system. The basic principle of realization of Dynamic Key Loging module is generating and distributing dynamic key at the server side, and clients login system according to the key after receiving it. So in this way, security for people to login system is improved. Second, the encrypted communications module is added in the system. RSA data encryption technology is adopted to transmit encrypted data in the system to further enhance the system security of information transfer, and make sure that chat security is more secure. In addition, this module also has played a digital signature role, which can prevent information from tampering, repudiating and make client authentication in transmission. Third, Short Message Service module is added in the system. This module is implemented based on the SMS cat technology, and it has made an important extension in video conferencing system. This module allows mobile phone users to send and receive cell phone message to join the video conference, which greatly facilitate the users.Finally, the thesis has summarized all the work, and prospected the future of video conferencing systems.更多还原