computeKey.py

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# -*- coding: utf-8 -*-
 
import numpy as np
 
from pyACA.computeSpectrogram import computeSpectrogram
from pyACA.ToolComputeHann import ToolComputeHann
from pyACA.computeFeature import computeFeature
 
 
 
def computeKey(x, f_s, afWindow=None, iBlockLength=4096, iHopLength=2048):
 
    # compute window function for FFT
    if afWindow is None:
        afWindow = ToolComputeHann(iBlockLength)
 
    assert(afWindow.shape[0] == iBlockLength), "parameter error: invalid window dimension"
 
    # key names
    cKeyNames = np.array(['C Maj', 'C# Maj', 'D Maj', 'D# Maj', 'E Maj', 'F Maj', 'F# Maj', 'G Maj', 'G# Maj', 'A Maj', 'A# Maj', 'B Maj',
                         'c min', 'c# min', 'd min', 'd# min', 'e min', 'f min', 'f# min', 'g min', 'g# min', 'a min', 'a# min', 'b min'])
 
    # template pitch chroma (Krumhansl major/minor), normalized to a sum of 1
    t_pc = np.array([[6.35, 2.23, 3.48, 2.33, 4.38, 4.09, 2.52, 5.19, 2.39, 3.66, 2.29, 2.88],
                    [6.33, 2.68, 3.52, 5.38, 2.60, 3.53, 2.54, 4.75, 3.98, 2.69, 3.34, 3.17]])
    t_pc = t_pc / t_pc.sum(axis=1, keepdims=True)
 
    # extract audio pitch chroma
    v_pc, t = computeFeature("SpectralPitchChroma", x, f_s, afWindow, iBlockLength, iHopLength)
 
    # average pitch chroma
    v_pc = v_pc.mean(axis=1)
 
    # compute manhattan distances for modes (major and minor)
    d = np.zeros(t_pc.shape)
    v_pc = np.concatenate((v_pc, v_pc), axis=0).reshape(2, 12)
    for i in range(0, 12):
        d[:, i] = np.sum(np.abs(v_pc - np.roll(t_pc, i, axis=1)), axis=1)
 
    # get unwrapped key index
    iKeyIdx = d.argmin()
 
    cKey = cKeyNames[iKeyIdx]
 
    return cKey
 
 
 
def computeKeyCl(cPath):
    from pyACA.ToolReadAudio import ToolReadAudio
    
    [f_s, afAudioData] = ToolReadAudio(cPath)
    # afAudioData = np.sin(2*np.pi * np.arange(f_s*1)*440./f_s)
 
    cKey = computeKey(afAudioData, f_s)
    print("\ndetected key: ", cKey)
 
 
if __name__ == "__main__":
    import argparse
 
    parser = argparse.ArgumentParser(description='Compute key of wav file')
    parser.add_argument('--infile', metavar='path', required=False,
                        help='path to input audio file')
 
    args = parser.parse_args()
    cPath = args.infile
 
    # only for debugging
    if not cPath:
        cPath = "c:/temp/test.wav"
 
    # call the function
    computeKeyCl(cPath)