A Study On Communication System Of Mobile Multimedia Terminal

Along with the development of 3G network and the constantly increased performance of chips and decreasing costs, the application of mobile multimedia terminal based on 3G network is becoming more and more widespread, such as video conference, video monitor and so on, and the communication between terminals becomes more and more important. Because of its merits of simple, open, compatibility and extendibility, SIP developed rapidly and it has tremendous value on research of multimedia conversation; The H.264 video coding has high compression rate and was supported by most mobile chips, so it becomes hot research points in industry and academia; The transfer protocol about streaming media is also tending perfect, and it also puts new demands on security in communication system.This thesis proposed by video conversation based on 3G network between terminals, it aims to design a kind of mobile multimedia terminal that assure to the performance of communication and security. The whole system uses SIP protocol to create session between two parties; and uses H.264 protocol to video codecs with lightweight encryption properly to ensure its security; and uses RTP/RTCP protocol to transfer H.264 compressed video packets, and designed a video parameters regulation module to adapt the changes in network, ensure the transmission quality.This thesis takes SAMSUNG arm11 s3c6410 chip as nucleus, takes the effective demand as the base, and mainly do research as follows:Researched on SIP protocol and got well understanding about its rationale, based on this implemented the client side codes.Researched on many types of video codec, according to the network performance and hardware demand, took H.264 as the type of video codec in client finally, and it adopted a simple encryption.Researched on and got well understanding about H.264 protocol and RTP/RTCP protocol, and used a RTP streams load format for H.264 video coding.Researched on correlative control method, according to RTCP protocol, designed a simple method about the control of video coding parameters, which can ensure the quality of service.After the research of all above, the writer built a platform of mobile multimedia terminal to make an overall test. According to the test, the system met the writer's requirements, and had good performance in video communication.