I\'m currently looking to access libavutil, libavformat and libavcodec (all part of FFMpeg) from .NET.
Currently, I\'m getting the libraries from the automated build
I've steered clear from any of those libraries/projects. All info I found at the time pointed to those breaking too easily with new versions and/or just being too out of date.
What I did is was run the ffmpeg process directly, as I mentioned on this answer, by modifying a sample in a blog post I link there. To this date we've not had trouble with it :)
If the above doesn't work for your scenario, good luck.