I'm a C++ developer too and with my company we develop a video acquiring software for medical purposes base on DirectShow. By now we are still using VMR7 of DirectX9 and we did not use the EVR of DirectX10Hello audio, I implemented the VMR9 filtering controls. I am unaware of any interfaces that the EVR exposes that allow to do something similar.
I know that in DirectShow there's the "Intelligent connect"... but on what it could base the choice of the stretching algorithm? Maybe on the hardware resources?With any luck its intelligently choosing it.