The entry-point function, DriverProc, processes messages sent by the system to the driver as the result of an application call to a low-level video capture function. For example, when an application opens a video capture device, the system sends the specified video capture device driver a DRV_OPEN message. The driver's DriverProc function receives and processes this message. Each of the different capture channels will receive a separate DRV_OPEN message.
Note Your driver should respond to all system messages. If supplemental information is not provided for them in this chapter, use the definitions provided in the Microsoft Windows Programmer's Reference.