| In recent years, the development of electronics, communications, computers and other technology promotes the popularity of the network and the development of embedded technology. It have been influencing on people’s learning, work and life in an extensive and far-reaching way. With the development of network communication technology, multi-media technology and the embedded technology, the embedded video transmission system has been widely used in security, transportation and industrial control, etc. Most of the traditional video transmission systems depend on the wired network, the complex structures of these systems, the high cost and the poor flexibility. Due to the development of wireless communication technology, wireless network transmission rates continue to improve, wireless video transmission system has broken the traditional cable video transmission system limitations.A wireless video transmission system which is based on embedded Linux system focuses on application. It combines wireless communication technology, embedded technology and multi-media technology, etc. Compared with the traditional video transmission system, this system has advantages of convenient, maintain simply, pratical, relatively low prices, etc. It has become a hot research of security field with a high theoretical research significance and practical application value.The paper is to design a wireless video transmission system which is based on embedded Linux system. The ARM9microprocessor is used as the core of the system’s hardware platform and the embedded Linux as the software platform, a USB wireless Wi-Fi card is used as the video transmission module. The paper first introduces the status and future trends of video transmission system. This article gives the overall design on the basis of application requirements of this paper and detailed introduces hardware architecture and software architecture, and the main hardware devices and software are selected. Software is established on the basis of hardware platform which includes the cross-development environment is established, the embedded Linux, USB wireless card driver and camera driver are transplanted to development board.After that, the paper focuses on how to realize the fuction of the system and detailed analyses the fuction of application program of the video transmission system server. The main function of server includes video data acquisition, encode and transmission. The video data acquisition module mainly uses V4L2interface which is offered by Linux kernel, and use the function of mmap to get the video data, which raise the efficiency of video data acquisition. The system adopts the function of write_jpeg which is offered by Linux libjpeg to compress video data. And the video transmission based on TCP/IP protocol. The system uses C/S mode and B/S mode to display the video at the same time, to realize it through transplanting the embedded Web server and MJPG-streamer video server to the development board.Finally, the function and performance of the whole system are tested after completing the design of system, the test results show that the system can realize the video data acquisition, compression, real-time wireless network transmission and display. It is stable and reliable and achieves desired functionality. |
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