| Real-time video monitor system is widely used in finance, electric power, transporting and logistics industry. With the development of IP network technology, video monitor system has developed from closed circuit TV to the third generation digital video monitor system based on IP network. Real-time video monitor system needs to transport a large number of video data and meet the request of time delay and smoothness. It's needs to solve the problem about video data compression, coding, transport,rate control, and play. But the IP network can only provide best effort service, can't provide effective control mechanism about QoS(Quality of Service), it doesn't suit to transport video data of real-time vide monitor system.This paper do some analysis of the standard of H.264 and RTP(Real-time Transport Protocol), designed a RTP-based real-time H.264 video monitor system. Realized the video capture, compression, net transport, decoding and play of the system. Designed the private protocol CAM IP(IP CAM Interface Protocol) which is used to finish the communication between server and client. Finished the analysis of CAM IP and realized the control of PTZ, recording, H.264 picture parameters and other aspect of the system.Analyses the QoS parameters like bandwidth, loss rate and jitter which effect the video quality of the real-time H.264 video monitor system, uses the double buffer technology to overcome the effect of jitter to decoding and play. Designed the net transport scheme of video streaming based on RTP protocol. Proposed a rate control algorithm based on RTP/RTCP(Real-time Transport Control Protocol) protocol and TCP's congestion control algorithm which called AIMD(Additive Increase and Multiplicative Decrease). Parameters represent network status which feedback by RTCP protocol is used to calculate the bandwidth of current network, the coder's out coding rate is adjusted dynamically according to current bandwidth, so to predict and control network congestion. At last, this paper designed a model about H.264 rate control. Simulation experiment of H.264 monitor system based on this model show that the RTP transport scheme and rate control algorithm can adjust coding rate according to network status fastely and smoothly. It maintains a lower loss rate and jitter value, can control network congestion effectively and improved the quality of video service of this H.264 video monitor system. |
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