Design And Research Of Network Multimedia Communication System

In the popularization of the network technology and multimedia technology now, more and more communication tools and instruments come into people’s life. Traditional communication tools are often limited to the transmission of sound signal, so this way can’t express the information well between the two sides of communication on some special occasions, such as:in some noisy environment, or communication between the deaf and dumb, etc.The technology of Multimedia network communication is a combination of network communication and multimedia technology, which takes in the efficiency of data transmission via network and the diversity of multimedia information to make interpersonal communication more quick, clear and intuitive. The technology has been widely used in distance education teaching, video conferences and seminars, and other fields, which makes the education way is more convenient and open, and make a difference to share teaching resources.In view of the singleness of the traditional communication mode, the network multimedia communication system make a improvement on the traditional communication tools based on the multimedia network communication technology. The system contains the function of graphic communication on the basis of the existing language communication function. The communication process is as follows:under the conditions of establishing communication between both sides, the sender in system can write and draw something on the touch screen, then, ARM processor collects the data and display it on the LCD screen after writing finished. ARM processor also compress the graphic data with the lossless compression method, and put the data in the RTP package. Then the graphic data will be processed with the speech processing module for synchronization with voice data, finally, the system will send RTP packets on the network. The receiver of system gets packets from Ethernet which is transmitted by the sender, then judges the packet type:voice or graphic. If the packet contains graphic data, the graphic processing module will unpack the data packets and display on the LCD.In addition, this article discusses every function module of the network multimedia communication system in detail. The hardware circuit design mainly includes the selection of embedded microcontroller processor, audio chips, LCD interface circuit, and the design of network card interface. In terms of software design, this paper firstly analyzes the structure of the embedded system, the transplantation of the embedded operating system. And the transplantation of RTP transmission protocol is also introduced. The paper discusses the speech processing module, the voice codec algorithm, and the principle of lossless compression algorithm in graphic processing module and program implementation in detail.