MediaSDK has the following hardware implementation definitions:
Is there any hardware, which really has second, third and fourth adapters working simultaneously?
For modern OS and D3D devices in 'client' systems, there is generally only one Intel D3D device integrated in the processor, but there can also be many discrete PCIe devices in use at the same time. This MFX_IMPL_HADWARE* definition provides an identifier to know which one has hardware implementation of MSDK API.
(The D3D resources (memory) used for MediaSDK must be resources created by the correct device).
Older OS used to have architecture of one adapter for each display.