Wifi-based Embedded Wireless Video Capture System Design

With the society development, the video capture system is more and more importmt in our life, we need it in a lot of place, however, it is not suitable for cabling or cumbersome wiring in somewhere with traditional wired video capture system, we need to use wireless in such case. Video traffic has become very more in the high-deinition video applictions, but the GPRS-based wireless transmission cannot reach the required rate, so we need to solve all the problems encountered above with wifi based on 802.11.In this paper, wireless monitoring program with wifi for video transmission is proposed according to the requirements of wireless video transmission, it can achieve remote monitoring via IP address. First, the paper analysis the structure of the 802.11 and the formation of transmission packet, and select the individual functional modules according to the actual need, the master controller is S3C2440, the camera module is OV9650 and the wireless module is 88W8686; and then build a software environment which each module can run with bootloader transplantation, making the file system, the kernel cuts, camera-driven migration and porting wireless network card driver, Camera module communicate the master controller with the I2C bus,and the wireless module communicate the master controller with the SPI bus. the video encoding format is H.264, and then put the compressed video data to the Inernet; the client module design which running on a remote PC is based on the DirectShow filter graph model, the video playback is not coherent for some wireless network environment have big change, and than it need to optimize the video frame, the network state parameters, video acceleration threshold, video deceleration threshold, delay frames, video frame rate, video frame rate and video frame rate benchmark variation of these parameters to adjust the frame rate, the last result is video broadcast coherent. I have been tested the results of the program implementation of wifi monitoring system, the test results meet the design objectives, the functions meet system requirements.