algorithmmidiaudio-processing

Algorithm to get the Key and Scale from musical notes?

From a series of MIDI notes stored in array (with MIDI note number), does an algorithm exist to get the most likely key or scale implied by these notes?

Solution

  • If you're using Python you can use the music21 toolkit to do this:

    import music21
score = music21.converter.parse('filename.mid')
key = score.analyze('key')
print(key.tonic.name, key.mode)

    if you care about specific algorithms for key finding, you can use them instead of the generic "key":

    key1 = score.analyze('Krumhansl')
key2 = score.analyze('AardenEssen')

    etc. Any of these methods will work for chords also.

    (Disclaimer: music21 is my project, so of course I have a vested interest in promoting it; but you can look at the music21.analysis.discrete module to take ideas from there for other projects/languages. If you have a MIDI parser, the Krumhansl algorithm is not hard to implement).