The DriverProc Function, Compression Drivers

Compression drivers provide a DriverProc entry point to process messages related to requests for video compression and decompression. The DriverProc function processes messages sent by the system to the driver as the result of an application call to a video compression and decompression function. For example, when an application opens a video compression and decompression driver, the system sends the specified driver a DRV_OPEN message. The driver’s DriverProc function receives and processes this message. Your DriverProc function should return ICERR_UNSUPPORTED for any messages that it does not handle.