Y1                174 ext/gd/libgd/webpimg.c double GetPSNRYuv(const uint8* Y1,
Y1                190 ext/gd/libgd/webpimg.c       double diff = Y1[row_idx + x] - Y2[row_idx + x];
Y1                215 ext/gd/libgd/webpimg.c double WebPGetPSNR(const uint8* Y1,
Y1                234 ext/gd/libgd/webpimg.c   psnr = GetPSNRYuv(Y1, U1, V1, Y2, U2, V2, w, h);