void RGBto422 (unsigned char *rgb, unsigned char *yuv, int width, int
height)
{
int r, g, b, Y1, Cb1, Cr1, Y2, Cb2, Cr2, x, y;
for(y = 0; y<height; y++)
for(x = 0; x < width; x += 2) {
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y1 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb1 = (b - Y1) / (2. - 2. * 0.1145);
Cr1 = (r - Y1) / (2. - 2. * 0.2989);
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y2 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb2 = (b - Y2) / (2. - 2. * 0.1145);
Cr2 = (r - Y2) / (2. - 2. * 0.2989);
*yuv++ = (unsigned char) (128 + (Cb1 + Cb2) / 2) * 224./255.+ 16;
*yuv++ = (unsigned char) Y1 * 219./255/ + 16;
*yuv++ = (unsigned char) (128 + (Cr1 + Cr2) / 2) * 224./255.+ 16;
*yuv++ = (unsigned char) Y2 * 219./255/ + 16;
}
}
//a nd for completeness 411:
void RGBto420 (unsigned char *rgb, unsigned char *yuv, int width, int
height)
{
int r, g, b, Y1, Cb1, Cr1, Y2, Cb2, Cr2, Y3, Cb3, Cr3, Y4, Cb4, Cr4,
x, y;
for(y = 0; y<height; y += 2)
for(x = 0; x < width; x += 2) {
r = *rgb;
g = *(rgb+1);
b = *(rgb+2);
Y1 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb1 = (b - Y1) / (2. - 2. * 0.1145);
Cr1 = (r - Y1) / (2. - 2. * 0.2989);
r = *(rgb+3);
g = *(rgb+4);
b = *(rgb+5);
Y2 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb2 = (b - Y2) / (2. - 2. * 0.1145);
Cr2 = (r - Y2) / (2. - 2. * 0.2989);
r = *(rgb+3*width);
g = *(rgb+3*width+1);
b = *(rgb+3*width+2);
Y3 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb3 = (b - Y3) / (2. - 2. * 0.1145);
Cr3 = (r - Y3) / (2. - 2. * 0.2989);
r = *(rgb+3*width+3);
g = *(rgb+3*width+4);
b = *(rgb+3*width+5);
Y4 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb4 = (b - Y4) / (2. - 2. * 0.1145);
Cr4 = (r - Y4) / (2. - 2. * 0.2989);
*yuv++ = (unsigned char) Y1 * 219./255/ + 16;
*yuv++ = (unsigned char) Y2 * 219./255/ + 16;
*yuv++ = (unsigned char) Y3 * 219./255/ + 16;
*yuv++ = (unsigned char) Y4 * 219./255/ + 16;
*yuv++ = (unsigned char) (128 + (Cb1 + Cb2 + Cb3 + Cb4) / 4) * 224./255. + 16;
*yuv++ = (unsigned char) (128 + (Cr1 + Cr2 + Cr3 + Cr4) / 4) * 224./255. + 16;
rgb += 6;
}
}
void RGBto411 (unsigned char *rgb, unsigned char *yuv, int width, int
height)
{
int r, g, b, Y1, Cb1, Cr1, Y2, Cb2, Cr2, Y3, Cb3, Cr3, Y4, Cb4, Cr4,
x, y;
for(y = 0; y<height; y++)
for(x = 0; x < width; x += 4) {
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y1 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb1 = (b - Y1) / (2. - 2. * 0.1145);
Cr1 = (r - Y1) / (2. - 2. * 0.2989);
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y2 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb2 = (b - Y2) / (2. - 2. * 0.1145);
Cr2 = (r - Y2) / (2. - 2. * 0.2989);
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y3 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb3 = (b - Y3) / (2. - 2. * 0.1145);
Cr3 = (r - Y3) / (2. - 2. * 0.2989);
r = *rgb++;
g = *rgb++;
b = *rgb++;
Y4 = 0.2989 * r + 0.5866 * g + 0.1145 * b;
Cb4 = (b - Y4) / (2. - 2. * 0.1145);
Cr4 = (r - Y4) / (2. - 2. * 0.2989);
*yuv++ = (unsigned char) Y1 * 219./255/ + 16;
*yuv++ = (unsigned char) Y2 * 219./255/ + 16;
*yuv++ = (unsigned char) Y3 * 219./255/ + 16;
*yuv++ = (unsigned char) Y4 * 219./255/ + 16;
*yuv++ = (unsigned char) (128 + (Cb1 + Cb2 + Cb3 + Cb4) / 4) * 224./255. + 16;
*yuv++ = (unsigned char) (128 + (Cr1 + Cr2 + Cr3 + Cr4) / 4) * 224./255. + 16;
}
}
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