How to install two missing media dlls?

I’ve just compiled the dlls for opencv from source in order to use the CUDA backend in Unity. However, now with everything in place things won’t yet work because I’m missing two dlls. Dependencies tells me they are:

ext-ms-win-media-codecpack-mounting-11-1-0.dll

ext-ms-mf-pal-12-1-0.dll

They appear to be media related. What are these for and how do I install them?