The Study Of Stream Media Transmission System Based On3G

With the rapid development of modern science technology and the growing demands for wireless video communication, the video wireless transmission has played an increasingly important role in modern video communication systems. At the same time, a variety of wireless communications and video codec technology have been paid much attention. Wireless video transmission system has unique advantages and wide application prospects, and it has become a hot research topic in the current communications and a development direction in the future. With this, it has been widely used in modern production, life, work, military, and many other ranges of application fields.In this paper, with the analysis and study of the common wireless video transmission technologies in the market, we propose a design of wireless video transmission system based on WCDMA network transmission. The specific functions achieved by this program are as follows:First, the video can be captured by the camera intstalled on the remote server, and be compressed and encoded by the H.264standard; Second, the encoded video stream can be sent by the wireless module of WCDMA, and be transmitted to the fixed IP client, through the WCDMA and internet netwowrk. Last, client software can receive, decode and display the video. In this system, the special dual-core video development board, SEED-DVS6446, is used as the hardware development platform for the video server. The Linux system is used as the software development enviroment. The HuaWei EM770W wireless module is choosed as the video transmission module. The DirectShow software based on the Windows system is slelcted as the remote client software, realizing to receive, decode and display the encoded video stream.The main work of this paper is to accomplish and complete the design of wirelss video transmission system based on WCDMA network. The main works needed to accomplish are divided into the following three parts.(1) For the server part, we need to build the software and hardware development platform. The ORTP protocol must be transplanted and applied to the Linux system. The capture, coding, storage, packet-split and sending control operations for video images are also needed to be accomplished.(2) For the wireless sending and transmission part, we must load the communication driver for the EM770W module, and configure the Linux inner-core for PPP protocol to dial-up and conncet to the internet. We must develop the scripts for EM770W to dial-up and connect to internet in AT commands.(3) For the client part, we must build the DirectShow development envieroment. For this part, the ORTP protocol is used to receive the video images in the network transmission. At the same time, the DirectShow technology is applied to decode and display the video images. At the end of this paper, we use method of the system experiment and test to prove that the wireless video transmission system based on the WCDMA network can successfully transmit the video images, and it is feasible.The features of this paper lie in these aspacets:First, the combination of WCDMA mobile communication technology and H.264digital video compression technology make it possible to realize the wireless video transmission system, which is with large capacity, high speed and stable performance. In this system, the Linux system is used as the software development environment, and the Davanci development board SEED-DVS6446and the3G wireless communications module are used as the hardware development platform. Meanwhile, the3G communications network and the internet are used as the transmission media. With these, the system is integrated with the capture, coding, compression, transmission, receiving, decoding and display operations for video images. Thus, it can effectively reduce development complexity for video surveillance systems. Second, the Non-tables Look-up Search Algorithm (NTLS) is added into the H.264decoding algorithm to improve the decoding efficiency and speed. At the same time, the memory access, power consumtion and the storage space are also reduced.