preprocessing.py 文件源码

def downSample(data, sampleRate = 20000, dsType = 'mean'):
    """ Function that downsamples data.

    :param data: list including syllables with sample data
    :param sampleRate: desired samplerate
    :param dsType: Type of interpolating used for downsampling.
                   Can be mean or IIR, which uses an order 8 Chebyshev type 1 filter (default = mean)

    :returns syllables: downsampled data, in same format as input data
    """

    syllables = []
    for syllable in data:
        samples = []
        for sample in syllable:
            SR = int(np.round(sample[1]/float(sampleRate)))
            if dsType == 'mean':
                pad_size = int(math.ceil(float(sample[0].size)/SR)*SR - sample[0].size)
                s_padded = np.append(sample[0], np.zeros(pad_size)*np.NaN)
                s_new = sp.nanmean(s_padded.reshape(-1,SR), axis=1)
            elif dsType == 'IIR':
                s_new = ss.decimate(sample[0],SR)
            samples.append([s_new, sampleRate])
        syllables.append(samples)
    return syllables

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