# RGB与YCbCr颜色空间的变换

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RGB与YCbCr颜色空间的转换

//数字RGB与YCbCr颜色空间转换的精度
//在这两个公式中RGB和YCbCr各分量的值的范围均为0-255。
// RGB转换为YCbCr
// 这个公式来自：Genesis Microchip. gm6010/gm6015 Programming Guide[M]. California US: Genesis Microchip Company, 2002:85-90
// |Y   |    |16  |                    |65.738   129.057  25.06 |   |R|
// |Cb| = |128| + (1/256)*|-37.945  -74.494  112.43| *|G|
// |Cr |    |128|                   |112.439  -94.154  -18.28|   |B|
// YCbCr转换为RGB
// 这个公式来自：Genesis Microchip. gm6015 Preliminary Data Sheet[M]. California US: Genesis Microchip Company, 2001:33-34
//|R|                   |298.082  0               408.58 |   |Y   -16  |
//|G| = (1/256)*|298.082  -100.291 -208.12|* |Cb-128|
//|B|                   |298.082  516.411   0           |   |Cr -128|

```// RGB转换为YCbCr

for(i =0 ; i < dest->dwSize; )
{
UCHAR r,g,b;
r = sBuf[i+0];
g = sBuf[i+1];
b = sBuf[i+2];
dBuf[i+0]= (unsigned char)(r * 0.256789 + g * 0.504129 + b * 0.097906)+ 16;
dBuf[i+1]= (unsigned char)(r *-0.148223 + g * -0.290992 + b * 0.439215)+ 128;
dBuf[i+2]= (unsigned char)(r * 0.439215 + g * -0.367789 + b *-0.071426)+ 128;
i += 3;
}
```

```// YCbCr转换为RGB

for(i =0 ; i < dest->dwSize; )
{
UCHAR y,u,v;
y = sBuf[i+0];
u = sBuf[i+1];
v = sBuf[i+2];
dBuf[i+0]= (unsigned char)(1.164383*(y- 16) + 0 + 1.596027*(v - 128));
dBuf[i+1]= (unsigned char)(1.164383*(y- 16) - 0.391762*(u - 128) - 0.812969*(v - 128));
dBuf[i+2]= (unsigned char)(1.164383*(y- 16) + 2.017230*(u - 128) + 0 );
i += 3;
}
```