The Design Of Video Monitoring System And Research Of Its Rate Control Algorithm

With the development of network technology and video encoding technology, network-based streaming service has been widely applied, resulting in a varitey of business such as video monitoring, video on demand and video conferencing. Meanwhile, as an important part of the security field, network video monitoring system has got more and more attention with the increasing awareness of security. Therefore, the study of video monitoring system is of great significance.In the research of video monitoing system, we generally use UDP protocol for the transmission of streaming media data. However, UDP protocol does not provide effective congestion control mechanisms, while general streaming media applications take up a lot of network resources. The lack of control mechanisms will result in the problem that the quality of streaming service can not be guaranteed effectively. Therefore, how to do the rate control based on the current network condition in order to improve the utilization of network resources and how to provide users with a better video service has become a hot topic.Aiming at these problems, this thesis designs and implements a network video monitoring system. The rate control algorithm of the streaming media data transmission is also studied. Firstly, the related technology of network monitoring system is introduced and the realization of its video capture front-end is discussed. Secondly, this thesis analyzes the problems caused by the lack of rate control algorithm in the video monitoring system and proposes several rate control algorithms which are applied to the streaming media data transmission. Finally, we designed a rate control algorithm called M-TFRC, which was appied to the media source to adapt to streaming media. Its application in video monitoring system is also proposed in this thesis.Considering that there are a number of lost packtes caused by the slow start phase in the TFRC algorithm, the proposed M-TFRC algorithm makes some improvement in the prediction mechanism of network bandwidth and the adjustment algorithm in slow start phase. Meanwhile, in order to obtain better quality video streaming, M-TFRC algorithm improves the smoothness and increases the throughput of multimedia data streams based on the TCP friendliness. The simulation show that the proposed algorithm can avoid a large number of packets loss caused by the slow start phase efficientlyand improve the utilization of network resources.