source: main/trunk/model-sites-dev/respooled/collect/popup-video-respooled/js/key-detection.js@ 29892

"use strict";

// From:
//  http://rnhart.net/articles/key-finding/

//major profile
//do    do# re  re# mi  fa  fa# so  so# la  la# ti
//6.35  2.23    3.48    2.33    4.38    4.09    2.52    5.19    2.39    3.66    2.29    2.88

//minor profile
//la    la# ti  do  do# re  re# mi  fa  fa# so  so#
//6.33  2.68    3.52    5.38    2.60    3.53    2.54    4.75    3.98    2.69    3.34    3.17


// kh = Krumhansl

var kh_major_profile = [6.35, 2.23, 3.48, 2.33, 4.38, 4.09, 2.52, 5.19, 2.39, 3.66, 2.29, 2.88 ];

var kh_minor_profile = [6.33, 2.68, 3.52, 5.38, 2.60, 3.53, 2.54, 4.75, 3.98, 2.69, 3.34, 3.17 ];


function khCreatePairing(profile,chromatic_scale_durations,offset)
{
    var pairing = [];
    for (var p=0; p<12; p++) {
    pairing.push({"p":profile[p],"c":chromatic_scale_durations[(p+s)%12]});
    }
    

    return pairing;
}


function khCreateAllPairings(chromatic_scale_durations,major_profile,minor_profile)
{
    // chromatic_scale_durations.length = 12

    var chromatic_keys = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"];

    var major_pairings = {};
    var minor_pairings = {};

    // Foreach scale
    for (var s=0; s<12; s++) {
    var scale = chromatic_keys[s];

    major_pairings[scale] = khCreatePairing(major_profile,chromatic_scale_durations,s);
    minor_pairings[scale] = khCreatePairing(minor_profile,chromatic_scale_durations,s);
    }

    return {"major" : major_pairings, "minor" : minor_pairings};

}