Design And Implementation Of Streaming Media Transmission Based On Embedded Linux

With the development of Embedded Video Monitoring System, the key technologies of Embedded Video Monitoring System are reseached , such as Streaming Media technology and video compression technology, in order to giving a design applied to embedded Linux system based on the system module of PC and used embedded device as hardware platform.The Real Time Protocol, RTP/RTCP grouping format and RTP Payload Format for H.264 Video are analysed at length in this paper. The H.264 Video transmission system with rate control and load disposed in application layer is designed. Besides, the Overall design of the software system is completed, and the implementations of each module are showed detailedly, such as NAL unit distilled module, H.264 video transmission system, rate control module which are the important part of this paper. First, NAL unit distilled module searchs the starting code of NALU in compressed video data at Davinci platform, then pushes video data to RTP thread as load throught shared memory mechanism. So this method can make the code of each module more clear, more convenient for debugging, and the performance of H.264 Encoded module will be not affected by any reason of RTP sender. At the same time, the H.264 Encoded module is modified to adapt to this system. Second, RTP, RTCP, and RTP Payload Format for H.264 Video are deeply analysed, in order to bring forward the tactic of H.264 video transmission. Third, in order to get the balance of quality of video and the bandwidth of net, rate control module is added to adjust the rate of video coding and sending based on the information of the SR and RR packet. Last, the relationship between coding rate and the distortion of video are reflected throught the testing pictures after unitary system testing.The system has high expansibility, agility and reuse, and adapts to embedded Linux system. The result of testing reveal that the system can achieve the anticipatice effect, and it accords with the trend of digital video, network system, intelligent management.