Research And Design Of Embeded Vedio Capturing And Transmission System Based On 3G

With the rapid development of information technology in today's society, the embedded technology has become one of biggest spots in IT technology.And with the network, video capture and compression technology development,video, audio and other multimedia data has become an important important content on the network transmission. However, the distance limitations of traditional wired transmission and the The time delay of data transmission based on 2G make further demands on wireless transmission of multimedia data.The appearance and generalization of 3G, combining with appropriate video compression capture technology, has overcome the wiring cost and problems caused by the low rate transmission, and make multimedia data wireless transmission truly achieve real-time transmission.In this background,the research of video capture and real-time transmission based on embedded system is practical and advanced.This system consists of three parts, respectively is video capturing and encoding terminal, video transmission part and data receiving center. Video capturing and coding terminal is based on S3C2440, using USB digit camera collect data, and compressing the data by MPEG-4 algorithm, and then packaging the data according to RTP. Video transmission part use 3G wireless network card transfer data via CDMA2000, and receiving center through Internet receive data.The system combine embedded Linux technology and wireless communication technology, implement the building of embedded Linux platform, the capturing of the video based on V4L. And using one of the MPEG-4 open source encooder XVID compress the video data.Finally,a feedback congestion control algorithm based on RTP/RTCP is designed, which is used for control the encoder's encoding rate and RTP packet sending rate,and has achieved the purpose of improving the transmission efficiency and reducing the packet lossing rate.