Design And Development Of Network Video Monitor System Based On Directshow And RTP

Along with society's progress, people have more requirements for the safety of life and the working conditions. The importance of monitor system appears especially prominently. Hence, the traditional simulation monitor cannot satisfy the users' needs anymore. Compared with the traditional simulation monitor, the digital monitor has various merits, such as suitable for computer processing, long-distance transmission, and search. It also has improved the picture quality and the monitoring efficiency, the system itself is easy to manage and maintain as well. DirectShow is a software development kit, which Microsoft Corporation develops based on the Windows platform software. It provides a whole solution for the Windows platform to process the preview and the audio/video collection of the media document.RTP/RTCP is a standard that was set up by IETF's (Internet Engineering Task Force) audio/video work team in 1996. RTP/RTCP is used to support the network real-time transmission service. RTP usually uses UDP to transmit data, and in the session, participant periodically transports the RTCP packages, which feed back the statistic information. RTP and RTCP used in cooperativity can provide the data real-time transmission and QoS service to satisfy the requirements of the delay and the packet lost for the network audio/video data real-time transmission.This thesis completed a small-size and practical network monitor system, by adopting the techniques above and using USB camera as the video collection equipment. The main work includes:(1) Using the UML modeling tool to complete the system's design. The thesis uses Rational Rose 2002 to create the user case diagrams, the class diagrams, and the activity diagrams for server-end and client-end, respectively. The system's coding process is accomplished according to these models.(2) Using the DirectShow, which is popular video management technology nowadays, to implement video data's gathering, preview, compression, decompression, replaying, and so on. Compression and decompression are realized by using advanced MPEG-4 coder and decoder.(3) Using dynamic link library technology to develop a simplified RTP protocol in order to achieve network transmission function of the monitor system. The simplified RTP protocol aims at the application environment of video monitor system, and can adapt the development better. Double buffering chain is used to reduce the network dithering, and an effective QoS control method is put forward to handle network congestion.(4) More perfect video recording function is implemented in both the server-end and the client-end. Recording files can be stored at hard disks in user-defined format, which can be replayed by special play window, or by Windows Media Player.(5) The client-end is implemented in way of EXE or ActiveX to support both C/S and B/S modes. Users can watch the monitor picture by installing the client software, or directly opening Internet Explorer to download the ActiveX control.