How can AVStream drivers capture video directly to the graphics adapter's VRAM?

  Hello everyone,Now I need the AVStream driver to capture video directly to the graphics adapter's VRAM.According to the Microsoft's WDK,one of the steps is to get the display adapter’s GUID.
  The WDK documents mention that "Obtain the adapter GUID from the vendor-supplied graphics miniport driver. The DXGK_INTERFACESPECIFICDATA structure contains the adapter GUID to return in the property request. This structure is generated by the DirectX graphics kernel (DXGK) subsystem and is passed to the miniport driver when the adapter is initialized."
  But I'm still puzzeled about the specific operations to get that display adapter’s GUID.Can you explain the specific operations to me?Thanks very much!