Design And Realization Of Web Client For Online Teaching Systems Based On HTML5&XMPP

Since we live in the era of proposing living and learning,for country,society or personal education is indispensable.But high cost of time and money is the stumbling block for most people to access to education.With the development of network technology,Online education is becoming more and more popular,in this way people can access to all the education they want with little cost of time and money.Online education is already become a trend,it also is an important way to realize lifelong learning for all.The existing online education system works in two ways:(1)acquiring real-time audio and video signals from teacher's the computer screen and then sharing to the student side,which in large part rely on the Flash technology.(2)Using HLS(HTTP Live Stream)to transmit media stream,although this method supports HTML5,package low rate ts fragment cost a lot.At present,the first application is the most extensive.Flash-based video playback requires the support of the browser plug-in,virtually increasing the difficulty of the user to obtain the video.Therefore,developing of an online teaching system that does not require Flash and supports live broadcast will be favored by more users.Based on the analysis of the existing online teaching system,this paper designs a set of online teaching system Web client based on HTML5 and XMPP protocol,which is used to realize real-time interactive,text chat,file upload and download and video transmission.(2)Combining Aspose component to finish format conversion such as word,pdf,ppt and excel.The core work of this paper is as follows:(1)Designing electronic whiteboard with Canvas to support multi-format document and collecting mouse operation signal in real time;(3)design XMPP real-time transmission channel;(4)solving problems such as collecting and coding video signals,system parallel problems;(5)HTML5 video label,Web RTC together with Canvas to achieve audio and video collection and playback.(6)Design and implement XMPP parser.The test results show that compare with the existing online system this scheme has the following advantages(1)getting rid of the dependence on the Flash plug-in;(2)reducing data which need to be transmitted on the network;(3)Teacher-side operation can be clearly shown on students' side,students no longer have to worry about the video is not clear.