streaming mode | Tonal category
- chords (string) - the chord progression
- key (string) - the key of the whole song, from A to G
- scale (string) - the scale of the whole song (major or minor)
- chordsHistogram (vector_real) - the normalized histogram of chords
- chordsNumberRate (real) - the ratio of different chords from the total number of chords in the progression
- chordsChangesRate (real) - the rate at which chords change in the progression
- chordsKey (string) - the key of the progression, taken as the most frequent chord
- chordsScale (string) - the scale of the progression, whether major or minor
Given a chord progression this algorithm describes it by means of key, scale, histogram, and rate of change. Note:
- chordsHistogram indexes follow the circle of fifths order, while being shifted to the input key and scale
- key and scale are taken from the most frequent chord. In the case where multiple chords are equally frequent, the chord is hierarchically chosen from the circle of fifths.
- chords should follow this name convention <A-G>[<#/b><m>] (i.e. C, C# or C#m are valid chords). Chord names not fitting this convention will throw an exception.
Input chords vector may not be empty, otherwise an exception is thrown.
 Chord progression - Wikipedia, the free encyclopedia, http://en.wikipedia.org/wiki/Chord_progression
 Circle of fifths - Wikipedia, the free encyclopedia, http://en.wikipedia.org/wiki/Circle_of_fifths
ChordsDescriptors (standard) Histogram (standard) Histogram (streaming)