Research And Application Of Videoconference Based On H.323 Protocol

With the development of network ,user's demand on network changes persistently . Multiple endpoints video conference based on IP network has been ideal choice of remote conference system because of it's lower cost and more advantage.There are two types of architectures for IP_based conference systems , which are respectively named as H.323 and SIP . The former is sticked up for ITU-T organization , and the latter is done by IETF . H.323 owing to the fact that its development time is long , and applies more extensively .This paper has carried on deeper analysis and study to the international standard of the existing video conference and relevant technology . Combining the actual project , we have developed a video conference system based on Internet and designed and implemented the overall frames and every functional module of the system.The main contents are:analyze the current multimedia confercencing system of network,and provide the overall framework, in addition provide tight coupling system architecture based on H.323,and Clent/Server as a model to achieve it;analyze and design the conference system center--MCU,and establish a data structure;How to use DirectShow technique to obtain multimedia data ; multimedia data transport over IP network ; multicast packet so as to control network flow ; As the core part of the system , conference control and manage are main concern in our design ; In addition , we discuss some useful techniques to resolve some difficult problem which are also very important in the system: Image-screen display, video/audio flow synchronous ,video/audio communication quality control. In the end of this article some difficult problems which need to resolve in the next step are discussed.