Dvd_manufacturer_descriptor

Has anybody got information that make sense by using the DVD_MANUFACTURER_DESCRIPTOR structure under Win32 and COM Development (Windows Driver Kit) on MSDN?
(http://msdn.microsoft.com/en-us/library/ms809042.aspx)

I have been trying to get the manufacturer code of a CD, DVD, …etc. But no luck so far. Below is the basic code segment that is supposed to do it… Any ideas?

Cheers, Chatai

DVD_READ_STRUCTURE r = {};
DVD_MANUFACTURER_DESCRIPTOR d = {};

hDevice = CreateFile(TEXT("\\.\D:"), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);

r.SessionId = 0;
r.Format = DVD_STRUCTURE_FORMAT::DvdManufacturerDescriptor;

hr = DeviceIoControl(hDevice, IOCTL_DVD_READ_STRUCTURE, &r, sizeof®, &d, sizeof(d), &count, NULL);