def ycbcr2rgb(y__, cb_, cr_):
    """Convert the three YCbCr channels to RGB channels.
    """
    kb_ = 0.114
    kr_ = 0.299
    r__ = 2 * cr_ / (1 - kr_) + y__
    b__ = 2 * cb_ / (1 - kb_) + y__
    g__ = (y__ - kr_ * r__ - kb_ * b__) / (1 - kr_ - kb_)
    return r__, g__, b__
