The Research And Realization Of Two Key Technologies Of Courseware On Demand System

Courseware on demand system is the very important part of long-distance education system. It transmits the video, voice of teachers and the electronic teaching plans to the students on demand via the modern communication network, simulating the education in school, and it creates comprehensive environment not restrained by the time and space for students. How to utilize the available teaching resource to improve the quality of study effectively and how to provide good study environment to the students are two important tasks for courseware on demand system.Now many teachers convert their teaching materials to electronic teaching plans, and in a great measure they convert these materials to PowerPoint. But if we put these teaching plans on net directly, these teaching plans can't synchronize with the video of teachers and it will depresses the effect of teaching. In the first part of this paper, we have researched the method to synchronize video, audio and electronic teaching plans PowerPoint. Convert the PowerPoint to a set of static images, and organize these images into streaming ones through RealPix file. After that, we associate the RealPix file with video through smil(Synchronized Multimedia Integration Language)file, and arrange the time and the layout of every media in web page. At last, we realize the synchronization of the video, audio and PowerPoint.In the second part of this paper, we have researched how to add the function of managing the study information of students to the Helix Client through modifying the video Tenderer plug-in. At first, this paper introduces the open source project Helix DNA Platform of RealNetworks corporation, then analyzes the framework and function of Helix Server and Helix Client in particular, then introduces the method of developing plug-in on Helix system and the relevant SDK facility. Using the network source object, stream source object and video renderer plug-in, we can retrieve the data we required, and organize the data through web page and smil files, and then we add the function of managing the study information of student to the Helix system.