After failing to find an up-to-date opus (http://opus-codec.org/) .NET wrapper, I came to the realization that (naudio) + (opus) might = (nice to use). The thing is, I've never actually used naudio, even though I have it downloaded and ready-to-go should the need arise. So, the question is, does naudio support the opus-codec, and if not, is it possible to make support for it, and, if so, what classes must one implement to allow this?
NAudio provides mechanisms to use codecs that are available through ACM or MFT in Windows. So if there is a version of the opus codec that conforms to either of those interfaces it could be used. Otherwise, custom interop wrappers would need to be created for the codec DLL.