This is a C# implementation of a beat detection algorithm described in this article on GameDev.net.
It came up as part of my research for Rise of the Undeaf.
License is MIT. The Fourier algorithm has been copied from https://github.com/hughpyle/inguz-DSPUtil under MIT license.
Quality of V1 detection is quite bad, except for fairly specific setups.
Licence for V2 is LGPL. The BeatDetektor and LanczosFFT have been ported (C++ to C#) from https://sourceforge.net/p/beatdetektor/ under LGPL license.
Due to the licensing split here (which I'm not completely sure how to handle) I suppose this has to be treated as a minimal standalone DLL, should it be incorporated into any other project.