If anyone is interested, Sonic Visualizer with it's vamp plugins is pretty state of the art when it comes to analyzing music. The Chordino NNLS Chroma plugin, for instance, can extract even jazz chords fairly accurately
> MFCC (mel-frequency cepstrum coefficients)<p>For anyone else who had never heard of "cepstrum" before, this is what I found on Wikipedia:<p>"The cepstrum is the result of computing the inverse Fourier transform of the logarithm of the estimated signal spectrum. The method is a tool for investigating periodic structures in frequency spectra. The power cepstrum has applications in the analysis of human speech.<p>The term cepstrum was derived by reversing the first four letters of spectrum. Operations on cepstra are labelled quefrency analysis (or quefrency alanysis), liftering, or cepstral analysis."
These are a nice set of tools. I used this long ago for extracting onset times from audio files: <a href="https://sighack.com/post/extract-onset-beat-times-from-audio-files" rel="nofollow">https://sighack.com/post/extract-onset-beat-times-from-audio...</a>
Funny, I stumbled upon this just today when I was looking for good realtime beat detection code.<p>Does anybody have experience, using some of this code for realtime detection?