Expert chord annotations of 20 tracks

The annotations of 20 tracks as detailed in this paper.

The folder "multiple_reference_annotations_v1.0" stores the annotations with song names, while folders "A1" to "A5" store the standardized annotations with indices that are used in the MIREX evaluation.

In Matlab format, the difficulty ratings by the annotators are:
SongTitleIndex = [3,9,28,33,85,87,97,101,111,115,138,139,140,157,173,181,182,189,195,199];
SongDifficultyScores = [
3 2 4 3 2 5 2 3 2 1 4 1 2 5 1 5 1 3 2 3; %A1
3 2.5 2 3 2 2 1 2 2 4 3 2 1 4 1 5 4 5 2 3; %A2
1 1 3 2 1 1 2 2 3 3 4 2 1 4 1 5 2 4 3 4; %A3
1 2 2 2 2 1 1 2 2 3 4 3 1 2 3 5 1 4 3 3; %A4
1 3 2 2 1 4 4 3 2 3 3 1 2 3 1 5 4 4 4 2 %A5
];