Design And Implementation Of Audio And Video Surveillance System Based On DirectX

As rapid development of multimedia information,computer networking technology and communications technology,the requirement for transporting real-time multimedia information is much higher. How to provide high-quality multimedia data stream processing becomes an urgent problem for DVR system. Network digital surveillance systems are usually based on Client/Server model, and this paper focuses on software realization of the client part.Real-time audio and video communication is highly required in bandwidth and timeliness, and it takes various models to cooperate to implement system function. So it's necessary to have efficient encoding methods, effective real-time transportation strategy and flexible developing platform. G.723.1 is a low bit rate speech coding standard whose compression rates can be 24;H.264 is a new video coding standard. It provides good video quality while achieving better coding efficiency, and it is the most efficient video compression standard at present. DirectX, which is released by Microsoft company, is a new generation of software packet for dealing with multimedia stream based on COM. It can effectively improve system's useability and expansibility by using DirectX.This paper reviews the development of DVR system, and expatiates on concept and theory about multimedia stream technology. Then it focuses on the design and implementation of the framework of the audio and video surveillance system based on DirectX. First,it generally introduces the whole system;Second, it discusses the detail information of the internal structure of each module, including audio data multi-buffer receiving, multithreading technology, DirectSound playing process;Video data cycle-pointer queue receiving, Filter development, constructing the Filter Graph. At last, it gives the whole system test method and all test results.