CUBE              108 libavfilter/af_afade.c         gain = 1.0 - cos(M_PI / 4.0 * (CUBE(2.0*gain - 1) + 1));
CUBE              134 libavfilter/af_afade.c         gain = CUBE(gain);
CUBE              146 libavfilter/af_afade.c         gain = gain <= 0.5 ? CUBE(2 * gain) / 2: 1 - CUBE(2 * (1 - gain)) / 2;