shithub: opus

ref: b6af21f31c9309e1ee031bb4c0cf51b213cf7f3c
dir: /dnn/ulaw.py/

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import numpy as np
import math

def ulaw2lin(u):
    return (math.exp(u/128*math.log(256))-1)/255


def lin2ulaw(x):
    s = np.sign(x)
    x = np.abs(x)
    u = (s*(128*np.log(1+255*x)/math.log(256)))
    u = np.round(u)
    return u.astype('int16')