YUV_FRAC           91 ext/gd/libgd/webpimg.c    v = (v + (257 << (YUV_FRAC + 2 - 1))) >> (YUV_FRAC + 2);
YUV_FRAC          101 ext/gd/libgd/webpimg.c   const int kRound = (1 << (YUV_FRAC - 1)) + (16 << YUV_FRAC);
YUV_FRAC          104 ext/gd/libgd/webpimg.c   return (luma + kRound) >> YUV_FRAC;