computeNoveltyFunction.py

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# -*- coding: utf-8 -*-
 
import math
import numpy as np
import matplotlib.pyplot as plt
from scipy.signal import filtfilt
from scipy.signal import find_peaks
 
import pyACA
from pyACA.computeSpectrogram import computeSpectrogram
from pyACA.ToolPreprocAudio import ToolPreprocAudio
from pyACA.ToolComputeHann import ToolComputeHann
from pyACA.ToolReadAudio import ToolReadAudio
 
 
 
def computeNoveltyFunction(cNoveltyName, x, f_s, afWindow=None, iBlockLength=4096, iHopLength=512):
 
    # compute window function for FFT
    if afWindow is None:
        afWindow = ToolComputeHann(iBlockLength)
 
    assert(afWindow.shape[0] == iBlockLength), "parameter error: invalid window dimension"
 
    hNoveltyFunc = getattr(pyACA, "Novelty" + cNoveltyName)
 
    # lp initialization
    fLenSmoothLpInS = 0.07
    fLenThreshLpInS = 0.14
    iLenSmoothLp = np.max([2, math.ceil(fLenSmoothLpInS * f_s / iHopLength)])
    iLenThreshLp = np.max([2, math.ceil(fLenThreshLpInS * f_s / iHopLength)])
 
    # pre-processing
    x = ToolPreprocAudio(x)
 
    # in the real world, we would do this block by block...
    [X, f, t] = computeSpectrogram(x, f_s, None, iBlockLength, iHopLength)
 
    # novelty function
    d = hNoveltyFunc(X, f_s)
 
    # smooth novelty function
    b = np.ones(iLenSmoothLp) / iLenSmoothLp
    d = filtfilt(b, 1, d)
    d[d < 0] = 0
 
    # compute threshold
    iLenThreshLp = min(iLenThreshLp, np.floor(len(d)/3))
    b = np.ones(iLenThreshLp) / iLenThreshLp
    G_T = .4 * np.mean(d[np.arange(1, d.shape[0])]) + filtfilt(b, 1, d)
 
    # find local maxima above the threshold
    iPeaks = find_peaks(d - G_T, height=0)
 
    return d, t, iPeaks[0]
 
 
 
def computeNoveltyFunctionCl(cPath, cNoveltyName):
    
    [f_s, x] = ToolReadAudio(cPath)
    # afAudioData = np.sin(2*np.pi * np.arange(f_s*1)*440./f_s)
    [d, t, iPeaks] = computeNoveltyFunction(cNoveltyName, x, f_s)
    
    # plot feature output
    if bPlotOutput:
        plt.plot(t, d)
    return d, t, iPeaks
 
 
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')
    parser.add_argument('--noveltyname', metavar='string', required=False,
                        help='novelty measure name in the format NoveltyFlux')
    parser.add_argument('--plotoutput', metavar='bool', required=False,
                        help='option to plot the output')
 
    # retrieve command line args
    args = parser.parse_args()
    cInPath = args.infile
    cNoveltyName = args.noveltyname
    bPlotOutput = args.plotoutput
 
    # only for debugging
    if __debug__:
        if not cInPath:
            cInPath = "../../ACA-Plots/audio/sax_example.wav"
        if not cNoveltyName:
            cNoveltyName = "Flux"
        if not bPlotOutput:
            bPlotOutput = True
 
    # call the function
    computeNoveltyFunctionCl(cInPath, cNoveltyName)