audio_tools.py 文件源码

def cheaptrick_smoothing_with_recovery(smoothed_spectrum, f0, fs, fft_size, q1):
    quefrency_axis = np.arange(fft_size) / float(fs)
    # 0 is NaN
    smoothing_lifter = np.sin(np.pi * f0 * quefrency_axis) / (np.pi * f0 * quefrency_axis)
    p = smoothing_lifter[1:int(fft_size / 2)][::-1].copy()
    smoothing_lifter[int(fft_size / 2) + 1:] = p
    smoothing_lifter[0] = 1.
    compensation_lifter = (1 - 2. * q1) + 2. * q1 * np.cos(2 * np.pi * quefrency_axis * f0)
    p = compensation_lifter[1:int(fft_size / 2)][::-1].copy()
    compensation_lifter[int(fft_size / 2) + 1:] = p
    tandem_cepstrum = np.fft.fft(np.log(smoothed_spectrum))
    tmp_spectral_envelope = np.exp(np.real(np.fft.ifft(tandem_cepstrum * smoothing_lifter * compensation_lifter)))
    spectral_envelope = tmp_spectral_envelope[:int(fft_size / 2) + 1]
    return spectral_envelope