Research And Realization Of Virtual Studio Based On Directshow Technology

In recent years, the virtual studio system has become one of technology in TV program making field. In this system, the three-dimensional scene which is produced by computer and the video scene which is produced by camera are composed synchronized. As result of synchronous change, the virtual studio system makes result more perfect. With the development of virtual studio system, more and more people pay attention to it.At the present time, the products of the virtual studio system are most based on the graphic workstation, which are too expensive to be used widely for normal users in China, so the research and realization of virtual studio system with low cost will change this situation. To break the limitation, this thesis is to develop a virtual studio system based on DirectX and PC, which can make it possible to apply virtual studio technology widely.The purpose of this thesis is to carry out the virtual studio system. Firstly, much key technology, such as the orientating and adjusting of camera, the plot of virtual scenes, the cutting and filling video, are quoted. The scheme of virtual studio system based on DirectX and PC is come up under comparing advantages and disadvantages of present virtual studio system. Secondly, this paper also introduces the matting technology and then chooses a matting algorithm based on Alpha through comparing others. Later, faster Alpha estimation arithmetic is used in program. Thirdly, the DirectShow technology is analyzed, especially in the design of filter. Last, the search and realization of virtual studio system based on DirectX and PC is introduced.On the basis of analyzing and designing above, the UI of virtual studio system is realized with MFC, including the configuration of system, the management of three-dimensional scene, the management of capture device ,the management of local video scene and the composition of the real-virtual video. Video composition of virtual studio system is achieved on DirectShow, including gathering video, the source filter of virtual video, cutting and filling video, title filter, etc. Finally this project is completed through implementing three parts which is consist of video composition based on DirectShow, three-dimensional scene based on Direct3D and the system UI based on MFC.During the design and realization of the virtual studio system, the object-oriented technology and design pattern are used, which make the system extensible and clear.