Design And Implementation Of WDM-based Virtual Camera

In recent years, with the development of sensor technology and multimedia processing technology, camera equipment has been popular and widely used. More and more Instant Messenger (IM), such as MSN, QQ and so on, provide the support of video communications. However, just transmission of the raw data collected from the cameras can not fully meet the growing demand for multimedia. More and more people would like to bring their computers to facilitate the efficient sharing of other video resources to let the other can watch it real-time.Based on the above motivation, relying on the video transmission functions of Instant Messenger, this paper expects to design a simple and common program to support user video data transmission real-time. However, the current situation of Instant Messenger shows: plug-in development environments provided by different Instant Messengers are different, and the video interfaces have not been provided. If we develop each IM independently, it will result in higher development costs and longer development cycle. In view of this, based on deeply studying the current situation of the video transmission mechanism and interfaces, this paper designed and implemented a virtual camera. The virtual camera proposed in this paper used the stream class virtual camera technology of Microsoft's Windows Driver Model (WDM) and supplemented efficient filter mode DirectShow mechanism to implement efficient transmission, processing and reception of user video data. When using this virtual camera, on one hand, magic video software outputs images to virtual camera; on the other hand, IM software, selects to obtain image data from the virtual camera in network video communication to achieving the purpose of the transmission of magic video. The application of filter mode DirectShow mechanism clears the data transmission structure, and reduces the number of data copy to the greatest extent as the video streams are transmitted between filters. Therefore, it reduces exertion of system memory and the time of CPU, and implements the sending and receiving of data rapidly.As this program has many advantages such as good universality, simple installation, rich colorful images export, and so on, with the fast development of internet and the prevalence of multimedia communication, it has broad application prospects in video chat, Network video conferencing, remote monitoring, etc.