Web-based Multimedia Collaboration Platform Implemented In Java

Traditional office work environment takes on a trend towards network virtual Collaborate work environment more and more with the development of Internet. Collaborate software tools which can make people intercommunicate "face to face" in formats of media becomes current hot research. With the development of economy and society,We can dope out developing this kind of software will get more and more impendence at some fields such as electronic business and remote education in the future.Many persons have been doing the research work in this field inside our country,but we have little good software because the development needs lots of compute knowledge and technology,and it is complex also. This problem looks more extrusion especially at the research aspect that using Java to develop multimedia collaboration workspace. At the same time,most of the public share collaboration systems aboard had been developed for many years,they have few multimedia functions especially in providing video conference aspect. Another shortage is that they are not pure Java program project.To solve these problems,this paper presents a new way,using Java program language develop a "pure Java" collaborate system based of browser/server which has virtues of better audio/video collaborate character. It provides many intercommunicate ways through groupware such as whiteboard,chat room,image slide and audio/video conference. Using the groupware,collaborate members can interchange their ideas very well.The system uses a four layer design framework (Java Applet client layer,communication manager layer,local service layer,Application & RTP server with database server layer). We use session manager to solve the problem of sending and receiving the multi formats of media data;use local service layer and Java Applet numeric underwrite mechanism to reading and writing the local resource.At the same time,the paper use Java Media Framework and RTP technology to solve the problem of transmission and playback of the audio/video stream. It also designs the mechanism of realizing audio/video conference. In Java runtime environment,a better method can be taken,this is to say,we expand the conception of JMFs "multiplexior",getting the "audio mixer" object to manage the audio stream and getting the "video mixer" object and the "token click and preempt" control mechanism object to manage the video stream. At last this solution method gives afford the facts below:The quantities of persons who join the audio collaborate do not been restricted and people do not need a voice authority before they speak.Furthermore,classification user purview control mechanism and consistency preserve are also the most common issue in collaboration systems. For the first issue,this paper uses a tree list and colorful leaves to show the state of the collaborate member and his access purview in whiteboard,moderator can manage all the other person's groupware access purview in centralized-control way,users can change their access purview during the collaboration conference is going on through a "raise one's hand to speak" mechanism. For the second one,this paper uses "locked object and centralize control" method to deal with it,but for the more special synchronization of the audio/video stream,the paper uses JMF's interior mechanism.Finally,the paper introduces a method to improve the transmission and playback quality through the MPEG-4 codec which write in pure Java.