SoundUtils.py 文件源码

def RMSWind(x, sr=1, nwind=1024, nhop=512, windfunc=np.blackman):
    '''
    Calculates the RMS amplitude amplitude of x, in frames of
    length nwind, and in steps of nhop. windfunc is used as
    windowing function.

    nwind should be at least 3 periods if the signal is periodic.
    '''

    nsam = len(x)
    ist = 0
    iend = ist+nwind

    t = []
    ret = []

    wind = windfunc(nwind)
    wsum2 = np.sum(wind**2)

    while (iend < nsam):
        thisx = x[ist:iend]
        xw = thisx*wind

        ret.append(np.sum(xw*xw/wsum2))
        t.append(float(ist+iend)/2.0/float(sr))

        ist = ist+nhop
        iend = ist+nwind

    return np.sqrt(np.array(ret)), np.array(t)