IMFVideoProcessorControl2::EnableHardwareEffects method:
Enables effects that were implemented with
IDirectXVideoProcessor::VideoProcessorBlt.[…] Specifies whether effects are to be enabled. TRUE specifies to enable effects. FALSE specifies to disable effects.
All right, it is apparently not IDirectXVideoProcessor and MSDN link behind the identifier takes one to correct Direct3D 11 API method: ID3D11VideoContext::VideoProcessorBlt.
Worse news is that having the effects “enabled”, the transform (the whole thing belongs to Media Foundation’s Swiss knife of conversion [with just one blade and no scissors though] – Video Processing MFT) fails to deliver proper output and produces green black fill instead of proper image.
Or, perhaps, this counts as a hardware effect.