rasta_plp_extractor.py 文件源码

def lpc2cep(a, nout=None):
    nin = np.size(a, 0)
    ncol = np.size(a, 1)
    order = nin - 1
    if nout is None:
        nout = order + 1
    c = np.zeros((nout, ncol))
    c[0, :] = -1. * np.log(a[0, :])
    renormal_coef = np.reshape(a[0,:], (1, ncol))
    renormal_coef = np.repeat(renormal_coef, nin, axis=0)
    a = a / renormal_coef
    for n in range(1, nout):
        sumn = np.zeros(ncol)
        for m in range(1, n+1):
            sumn = sumn + (n-m) * a[m, :] * c[n-m, :]
        c[n, :] = -1. * (a[n, :] + 1. / n * sumn)
    return c