Design & Implementation Of IP-based Videoconference System

With the development of the technology of multimedia and networking, text and voice communication via Internet can not meet the requirements of the people, and multimedia communication becomes more and more popular. Multimedia communication is a new widely used communication technology after telephone, telegraph and fax. Now Videoconference, an application of multimedia communication, applies networking technology and multimedia codec to realize a virtual conference. Through videoconference, people who are not in the same place can communicate freely and effectively with each other.After introduction and analysis of the current technology of videoconference, the design and implementation of a centralized IP-based videoconference system is presented. The system is composed of three components: conference control subsystem, conference management subsystem and terminal subsystem, and is implemented referring to SIP Centralized control conference system model, using a C/S architecture. Our system currently uses RTP/RTCP as the media control protocol, G726 standard as audio codec, H261/H263 standard as video codec and Unicasting/Multicasting as the methods of audio/video transportation. By judging the bandwidth of networking, user can freely adjust quality of video and rate of data forwarding. Further more, user can choose Unicasting or Multicasting, which is supported by devices of networking.This paper is organized as follow. The first chapter is a briefly introduction of key technologies of videoconference and the future development of videoconference. The second chapter discusses the architecture of our videoconference system. The design and implementation of the conference management subsystem and conference terminal subsystem are discussed in Chapter Three and Chapter Four respectively. Conference control subsystem is the core of the videoconference system, its design and implementation is presented in Chapter Five. Chapter Six analyzes the testing result of our system. At last, Chapter Seven concludes this thesis.