Design Of Embedded Wireless Real-time Video System

In multimedia communication, the limitations of voice communication make the demand of video communication become more and more intense. In current, most video communication system is designed based on PC, which is difficult to move, that make it limit to use. Although the application of 3G communication technology has improved the mobility of video communication equipment, it has a great cost and need to build a lot of base station. This paper puts forward a real-time video system, which transmits video information through wireless network in real-time, has good mobility, constructs networking quickly, has multiple video mode and can be controlled, would be applied to monitor system and outdoor video conversation and so on.Based on the hardware resources of DaVinci TMS320DM6446 board and the software structure of DaVinci technology, the paper realizes the wireless real-time video system. Firstly, according to the functions of the system, system structure is divided into multiple system module, and the paper designs hardware and software solutions for each module. Secondly, the paper expounds the specific design process of each software module. Actually, capturing module is designed based on V4L2, to control the capture device; encoding and decoding modules are designed based on Codec Engine technology , to implement video data processing; transmission and receiving modules are designed based on JRTPLIB APIs, to implement video data sending and receiving; displaying module is designed based on framebuffer technology, to implement image displaying. Finally, the paper use PIPE as the communication mechanism, mutex and conditions as the synchronization mechanism of each sub-module.By C/S structure,the paper constructs system software. The server has the task of handling a client request for a video session and completing video capturing, encoding and sending. The client has the task of initiating the video session to server and receiving the video data from server, decoding the video data and displaying. The wireless real-time video system, designed by this paper, has many video modes, and the server of it can be controlled through command by the client. Moreover, the paper tests the system and analysis the test results.Based on the DaVinci platform, the wireless real-time video system meets the requirements of real-time video communications well. Test results show that the system can work stably for a long time, display smoothly and little in delay, which achieves a good real-time effect.