Need a C# wrapper for video format conversion, please

Question

I need a C# wrapper for video format conversion. Such as converting a .flv video into other formats, like avi, mpeg4 and etc. I need compilable files or libs in C# not commercial softwares.
I noticed that there are ffmpeg and Tao.framework but there is no sample codes of how to do format conversion. Please help !!!!
Thank You!!