| These years, there is a big revolution in video communication domain. Obviously the progress of digital video is faster. Video communication has improved from analog signals to digital signals. Video meetings, digital TV and high definition TV are influencing our daily life more and more. The whole digital TV broadcast system brings the revolutionary changes from video creating to video transmission and broadcasting. In such condition, there are new demands for college students majored in video communication discipline. So it is necessary for academies to add new courses about video theory.More and more colleges and academies established digital video courses outside the pale of traditional video courses, so students can keep up with latest video encoding theories and technology. But these courses are more theory and lack of experiments, and also lack of experiment equipments. Students would feel that it is hard to understand these uninteresting theories.The purpose of this paper is to research a real-time digital video encoding system as an experiment equipment for digital video disciplines. In this object, we used the concept of MPEG-2/4 encoding standards and IPTV, so the learners can understand the theories about digital TV and network TV, and know the principles about video encoding and digital video transports.The common MPEG-2/4 series real-time encoding systems which we can get from markets are often professional and expensive. The disadvantage about these systems is hard to know the encoding progress, so it's hard for students'experiments. The other disadvantage is the expensive prices obstruct the large amount of purchase. In this paper, give a scheme which can realize low cost, real-time, high quality video encoding system with MIPS CPU and encoding chip. The system applies embedded Linux system and receives NTSC or PAL analog video/audio signals from video/audio input interface, encoding video/audio signals to MPEG-2/4 transmit streams or program streams with special encode chip, encapsulates in UDP/IP packets and transmit through Ethernet interface.In this paper,we introduce the design of hardware architecture first. Through analyzing every sub-module and popular designs, choose the fittest scheme for the system we want to get. Second, develop the software system base on the hardware architecture, includes compiling the embedded Linux operation system, compiling the encoding applications, compiling the system control software, etc. What we want to show is the main principle of MPEG series encoding, so we focus on the main principles in the process of this system development and give up the latest designs, for example, H.264 and high definition. Therefore we reduce the cost of development and utilization. As we use the modules designs, every module can be changed parameters, user can easy change the results of encoding. The low cost of hardware architecture reduce the procurement cost by college schools, and reduce the cost of opening experiment courses for digital video encoding. In addition, it is easy to show the whole processes about the encoding by modules design and so this system can be good used in college digital video experiment courses. It will have a good market prospect. |
