There is no comparison.
Media Foundation is the next generation multimedia platform for Windows that enables developers, consumers, and content providers to embrace the new wave of premium content with enhanced robustness, unparalleled quality, and seamless interoperability.
DirectX Video Acceleration (DXVA) is an API and a corresponding DDI for using hardware-acceleration to speed up video codec processing.
This and the material around it should clarify things:
MSDN: Supporting DXVA 2.0 in Media Foundation [
^]