audio_tools.py 文件源码

def cheaptrick_get_power_spectrum(waveform, fs, fft_size, f0):
    power_spectrum = np.abs(np.fft.fft(waveform, fft_size)) ** 2
    frequency_axis = np.arange(fft_size) / float(fft_size) * float(fs)
    ind = frequency_axis < (f0 + fs / fft_size)
    low_frequency_axis = frequency_axis[ind]
    low_frequency_replica = interp1d(f0 - low_frequency_axis,
            power_spectrum[ind], kind="linear",
            fill_value="extrapolate")(low_frequency_axis)
    p1 = low_frequency_replica[(frequency_axis < f0)[:len(low_frequency_replica)]]
    p2 = power_spectrum[(frequency_axis < f0)[:len(power_spectrum)]]
    power_spectrum[frequency_axis < f0] = p1 + p2
    lb1 = int(fft_size / 2) + 1
    lb2 = 1
    ub2 = int(fft_size / 2)
    power_spectrum[lb1:] = power_spectrum[lb2:ub2][::-1]
    return power_spectrum