audio_tools.py 文件源码

def lpc_to_lsf(all_lpc):
    if len(all_lpc.shape) < 2:
        all_lpc = all_lpc[None]
    order = all_lpc.shape[1] - 1
    all_lsf = np.zeros((len(all_lpc), order))
    for i in range(len(all_lpc)):
        lpc = all_lpc[i]
        lpc1 = np.append(lpc, 0)
        lpc2 = lpc1[::-1]
        sum_filt = lpc1 + lpc2
        diff_filt = lpc1 - lpc2

        if order % 2 != 0:
            deconv_diff, _ = sg.deconvolve(diff_filt, [1, 0, -1])
            deconv_sum = sum_filt
        else:
            deconv_diff, _ = sg.deconvolve(diff_filt, [1, -1])
            deconv_sum, _ = sg.deconvolve(sum_filt, [1, 1])

        roots_diff = np.roots(deconv_diff)
        roots_sum = np.roots(deconv_sum)
        angle_diff = np.angle(roots_diff[::2])
        angle_sum = np.angle(roots_sum[::2])
        lsf = np.sort(np.hstack((angle_diff, angle_sum)))
        if len(lsf) != 0:
            all_lsf[i] = lsf
    return np.squeeze(all_lsf)