Videoconference System Based On PC

Videoconference system is a kind of communication system that can transmit voice, image, text and various other information from one place to another place and can make the participants have real-time communication and cooperate with remote participants. Videoconference system can widely be applied to distance learning, remote medical service, remote training and other services that need real-time audio, video data transmission. As net condition has been improved, people's need to transmit multimedia information through by Internet is becoming more and more strong. So Videoconference system becomes a hot point in information technology at recent years.The price of traditional Videoconference system is expensive because it is based on hardware.This is a primary reason that Videoconference system cannot be used widely by ordinary users. As personal computer's capability become more and more strong and the coding technology has been improved greately, implementing Videoconference system with pure software become possible. Videoconference system based on software gets the advantage over traditional system in price and flexibility.In this paper I discuss the actuality and development trend of the multimedia Videoconference. The design process of a multimedia Videoconference system, transporting data by Internet, based on PC and implemented with pure software is showed. Based on the system, I discuss the method of developing net programs with Delphi and introduce the software Codec in Windows and the software interface for Codec, audio compression manager and video compression manager to perform real-time audio and video processing. Audio captures and Video captures based on DirectShow and Video display based on DirectDraw are introduced. We also discuss the method of synchronization for audio and video and the method of developing own component with Delphi. Corresponding program examples are provided for all discussion.