Because your driver handles the drawing of video, the client application does not need to determine the output format. The client application must only determine if your driver can handle the input format. It sends ICM_DRAW_QUERY to determine if your driver supports the input format. The input format is specified with a pointer to a BITMAPINFO data structure in dwParam1. The dwParam2 parameter is not used.
If your driver supports the specified input format, return ICERR_OK to indicate the driver accepts the format. If your driver does not support the format, return ICERR_BADFORMAT.