The Research Of H.264 Rate Control In Video Surveillance For Urban Rail Transportation

Video Surveillance for urban rail transportation is an important way for the Urban public security areas, is also a hotpot of research in the Video Surveillance area. With the continuous improvement of the hardware and software , the development of Video sampling technology, video compression and coding technology and video transmission technology, Video Surveillance for Urban rail transportation technology has also developed rapidly. As a new generation video coding standard developed jointly by ISO and ITU. H.264 employs a series of new technologies, improves video coding efficiency greatly, and has been nominated to be the most efficient video coding standard in recent years as a result. To achieve better image quality under the channel bandwidth, time-lapse and buffer limitation, appropriate strategies must be adopted to control the rate of encoder's output into a certain range.Therefore, rate control has become one of the key techniques of video coding, also is the Solution to achieve high quality video and high real-time requirement of Video Surveillance for Urban rail transportation.After discuession about the development status of video surveillance for urban rail transportation, the Related key technologies are analyzed, the video coding standard of H.264 is introduced, the basic principle of rate control is discuessed deeply, the reasons that cause the rate variance are analyzed, and the algorithms of several video coding standards are also reviewed ans summarized in this dissertation. Based on the existing research results of the rate control technique for H.264, considered about the actual requirement of videosurveillance for urban rail transportation, a rate control algorithm based on the linear regression for H.264 is proposed. With the theory of linear regression, the algorithm establishes two linear models of QP-PSNR and R-ρ-E_ρ-E_QP-QP in order to calculate more precise quantitative parameters, overcomes the limitation of existing algorithms in calculation efficiency, and achieves more effective rate control. The experimental results show that, the algorithm based on the linear outperforms the existing rate control algorithms for H.264 for rate estimation error ,video quality and buffer occupancy.With the theory discuessed above , an overall design of video surveillance for urban rail transportation is proposed, and a video surveillance system based on the linear regression is eastablished for a try, in order to prove the feasibility of the design and the availability of the rate control algorithm based on linear regression.