The Reaserch And Implemetation Of 3G IP Camera Based On I.MX27

With the perfection of 3G network,especially the increase of network transmission bandwidth,the research of wireless video surveillance system based on 3G network has become a hot topic in the field of video surveillance.Compared with traditional video surveillance system,it has many advantages such as high stability,good real-time and high scalabity.And it is proven that the research and development of video surveillance system based on 3G wireless network has high prospects in application.Therefore, on the basis of i.MX27 multimedia processor,embedded Linux operating system and CDMA2000 wireless network, a protype of 3G IP camera based on C/S mode is designed and implemented in this paper.The main research works of this paper are summarized as following:1. Designs the overall structure of the 3G IP camera on the basis of analyzing related technologies.Then designs a modified AIMD aglgorithm on the basis of analyzing the methods used in the transmission control of video stream,which can achieve effective control the sending rate of the server side according to the packet lost ratio and the status information of the receive buffer feedback from the receiver side.2. Sets up the hardware and software environment of the 3G IP camera based on LMX27 embedded microprocessor.By analyzing the coding configuration of i.MX27 and the features of H.264 video stream,designs a simplified RTP packaging method for video stream, achieves control information and data exchange between client and server.3. Designs and implements a client platform,including the design of the receiver buffer,reception of RTP packets and recovery of H.264 payload,decoding and display of H.264 video stream,as well as the feedback of RTCP information.And all the function modules are integrated into the ActiveX plug-in.4. The performance of the 3G IP camera is tested. The results show that video frame rate is up to 20fps in resolution of 352 multiplying 288. The decoded images of the client display well and can achieve continuous and real-time display of the surveillance video.