C++ Constant-Q

h1. Wiki

h2. The method

 * The method to be implemented is that from "Anssi's Constant-Q Toolbox page":http://www.eecs.qmul.ac.uk/~anssik/cqt/.

 * The MATLAB toolbox reference implementation is "here":/projects/constant-q-toolbox.

 * The "QM-DSP":/projects/qm-dsp library contains a Constant-Q implementation; there is a Vamp plugin of it in the "QM Vamp Plugins":/projects/qm-vamp-plugins set. I believe it is based on the method of Brown and Puckette. Our version isn't very good. Among other things, we should aim to produce an improved plugin.

*Any pointers to* other existing high-quality C++ constant-Q implementations?

*Has anyone already made one* corresponding directly to the Schörkhuber/Klapuri method? We don't want to duplicate effort. And if someone has, why don't I know about it? -- can we do anything to help make it more universally known?

*What other modern methods* exist in C++?

h2. What we want it for

The immediate requirement is as the first step in implementing Emmanouil Benetos and Simon Dixon's "music transcription":http://www.mitpressjournals.org/doi/abs/10.1162/COMJ_a_00146 method for a Vamp plugin.

But the reason we aren't using the QM-DSP constant-Q implementation is that it simply isn't good enough, and that means it isn't really good enough for the rest of the world either. We should make a better one to improve upon the existing QM Vamp Plugin as well.