YUV422与RGB互相转换（经验证在IPNC与PC上都可以）

前一段时间在DM8168中进行颜色空间的转换，在网上找了些程序，自己也根据网上的改了下，由于能力问题，实在是不好意思说做了好几天才弄出来， 主要是因为YUV<—>RGB有各种各样的转换公式。在多次的实验修改后，终于找到了对的公式，共享出来，以便需要的人选择。

在监控系统中大多采用YUV的颜色空间，原因不说了，网上搜YUV转RGB各种介绍。

在TI的视频英语达芬奇系列中（这里只测试了DVR、IPNC），

采用如下公式：

yCbCr<-->rgb
 
Y’ = 0.257*R' + 0.504*G' + 0.098*B' + 16
 Cb' = -0.148*R' - 0.291*G' + 0.439*B' + 128
 Cr' = 0.439*R' - 0.368*G' - 0.071*B' + 128

R' = 1.164*(Y’-16) + 1.596*(Cr'-128)
 G' = 1.164*(Y’-16) - 0.813*(Cr'-128) - 0.392*(Cb'-128)
 B' = 1.164*(Y’-16) + 2.017*(Cb'-128)

转换效果图如下

第一幅是原图YUV，第二幅是转为RGB后存为bmp，反转是因为BMP图像是从最下面一行开始存取的原因，最下面一副是转回YUV的图像。

代码如下，代码中YUV采用YUYVYUYV的格式，RGB为RGBRGBRGB…..

http://download.csdn.net/detail/guo8113/7318031(代码下载)

#ifndef _RGB2YUV__
#define _RGB2YUV__
#include
using namespace std;

#define TUNE(r) ( r < 0 ? 0 : (r > 255 ? 255 : r) )

static int RGB_Y[];
static int RGBR_V[];
static int RGBG_U[];
static int RGBG_V[];
static int RGBB_U[];

static int YUVY_R[];
static int YUVY_G[];
static int YUVY_B[];

static int YUVU_R[];
static int YUVU_G[];
static int YUVU_B[];

static int YUVV_R[];
static int YUVV_G[];
static int YUVV_B[];

static int coff_rv[];
static int coff_gu[];
static int coff_gv[];
static int coff_bu[];

//直接采用公式浮点计算方式
//仅RGB2YUV采用了查表法，所以有一部分表是没有用到的
void InitTable()
{
int i;
for(i = ;i<;i++)
{
//初始化表,放大256倍
RGB_Y[i] = * (i - );
RGBR_V[i] = * (i - );
RGBG_U[i] = * (- i);
RGBG_V[i]= *(-i);
RGBB_U[i] = * (i - );
//y=0.257*r+0.504*g+0.098*b+16
//u = -0.148*r - 0.291*g + 0.439*b + 128
//0.439*r - 0.368*g - 0.071*b + 128
YUVY_R[i]=*i;
YUVY_G[i]=*i;
YUVY_B[i]=*i;
YUVU_R[i]=-*i;
YUVU_G[i]=-*i;
YUVU_B[i]=*i;
YUVV_R[i]=*i;
YUVV_G[i]=-*i;
YUVV_B[i]=-*i;
/*所用公式(此公式不适用)
*pRGB = (unsigned char)(1.0*y + 8 + 1.402*(v-128)); pRGB++; // r
*pRGB = (unsigned char)(1.0*y - 0.34413*(u-128) - 0.71414*(v-128)); pRGB++; // g
*pRGB = (unsigned char)(1.0*y + 1.772*(u-128) + 0); pRGB++ ;
*/
coff_rv[i] = (+1.402*(i-))*;
coff_gu[i] = -0.34413*(i-)*;
coff_gv[i] = -0.71414*(i-)*;
coff_bu[i] = 1.772*(i-)*;

     /\*应该使用如下公式：  

Y’ = 0.257*R' + 0.504*G' + 0.098*B' + 16
Cb' = -0.148*R' - 0.291*G' + 0.439*B' + 128
Cr' = 0.439*R' - 0.368*G' - 0.071*B' + 128(标红的两组公式是可逆的转换)
R' = 1.164*(Y’-16) + 1.596*(Cr'-128)
G' = 1.164*(Y’-16) - 0.813*(Cr'-128) - 0.392*(Cb'-128)
B' = 1.164*(Y’-16) + 2.017*(Cb'-128)
*/
}
}

void YUV2RGB422(unsigned char *pRGB, unsigned char *pYUV,int size)
{
unsigned char y, u, v,y1;
int r,g,b;
unsigned int i=;
unsigned int loop = size>>;
while(loop-- >)
{

     y = \*pYUV; pYUV++;  
     u = \*pYUV; pYUV++;  
     y1 = \*pYUV;pYUV++;  
     v = \*pYUV; pYUV++; 

     r = 1.164\*(y-) + 1.596\*(v-);  
     g = 1.164\*(y-) - 0.813\*(v-) - 0.392\*(u-);  
     b = 1.164\*(y-) + 2.017\*(u-); 

     \*pRGB = TUNE(r);pRGB++;  
     \*pRGB = TUNE(g);pRGB++;  
     \*pRGB = TUNE(b);pRGB++; 

      r = 1.164\*(y1-) + 1.596\*(v-);  
      g = 1.164\*(y1-) - 0.813\*(v-) - 0.392\*(u-);  
      b = 1.164\*(y1-) + 2.017\*(u-);  
      \*pRGB = TUNE(r);pRGB++;  
      \*pRGB = TUNE(g);pRGB++;  
      \*pRGB = TUNE(b);pRGB++;  
  } 

}

//size 为图片的大小
void RGB2YUV422(unsigned char *pRGB, unsigned char *pYUV,int size)
{
unsigned char r,g,b,u,v,u1,v1,r1,g1,b1;
//unsigned char *YUVBuff;
//unsigned char* p;
//p = YUVBuff;//
int loop = size/;
int i;
for( i=;i<loop;i++)
{
r = *pRGB; pRGB++;
g = *pRGB; pRGB++;
b = *pRGB; pRGB++;
r1 = *pRGB; pRGB++;
g1 = *pRGB; pRGB++;
b1 = *pRGB; pRGB++;

      //new method ---  right  
      int y = ((YUVY\_R\[r\] + YUVY\_G\[g\] + YUVY\_B\[b\] + ) >> ) +;  
      u = ((YUVU\_R\[r\] + YUVU\_G\[g\] + YUVU\_B\[b\] + ) >> ) + ;  
      v = ((YUVV\_R\[r\] + YUVV\_G\[g\] + YUVV\_B\[b\] + ) >> ) + ;  
      int y1 = ((YUVY\_R\[r1\] + YUVY\_G\[g1\] + YUVY\_B\[b1\] + ) >> )+;  
      u1 = ((YUVU\_R\[r1\] + YUVU\_G\[g1\] + YUVU\_B\[b1\] + ) >> ) + ;  
      v1 = ((YUVV\_R\[r1\] + YUVV\_G\[g1\] + YUVV\_B\[b1\] + ) >> ) + ; 

      \*pYUV++ = TUNE(y);  
      \*pYUV++ =(TUNE(u)+TUNE(u1))>>;  
      \*pYUV++ = TUNE(y1);  
      \*pYUV++ = TUNE(v);  
  }    

}

void inline Yuv2RgbPixel(unsigned char y,unsigned char u,unsigned char v, unsigned char* rgbPixel)
{
int r = (RGB_Y[y] + RGBR_V[v] + ) >> ;
int g = ((RGB_Y[y] + RGBG_V[v] +RGBG_U[u]+ )>> );
int b = ((RGB_Y[y] + RGBB_U[u]+ )>>);
*rgbPixel=TUNE(r);rgbPixel++;
*rgbPixel=TUNE(g);rgbPixel++;
*rgbPixel=TUNE(b);
}

void YUV2RGB(unsigned char *pRGB, unsigned char *pYUV,int size)//444
{
unsigned char y, u, v;

  for(int i=;i<size;i++)  
  {  
      y = \*pYUV; pYUV++;  
      u = \*pYUV; pYUV++;  
      v = \*pYUV; pYUV++; 

      Yuv2RgbPixel(y,u,v,pRGB);  
      pRGB += ;  
  } 

}

void inline Rgb2YuvPiexl(unsigned char r,unsigned char g,unsigned char b,unsigned char* pYUV)
{
int y = ((YUVY_R[r] + YUVY_G[g] + YUVY_B[b] + ) >> ) + ;
int u = ((YUVU_R[r] + YUVU_G[g] + YUVU_B[b] + ) >> ) + ;
int v = ((YUVV_R[r] + YUVV_G[g] + YUVV_B[b] + ) >> ) + ;
*pYUV = TUNEY(y);pYUV++;
//*pYUV = u < 0 ? 0 : (u > 255 ? 255 : u);pYUV++;
*pYUV =TUNE(u);pYUV++;
*pYUV = TUNE(v);
}

void RGB2YUV(unsigned char *pRGB, unsigned char *pYUV,int size)
{
unsigned char r,g,b,y,u,v;
for(int i=;i<size;i++)
{
r = *pRGB; pRGB++;
g = *pRGB; pRGB++;
b = *pRGB; pRGB++;
Rgb2YuvPiexl(r,g,b,pYUV);
pYUV +=;

  }  

}
#endif

http://www.61ic.com/Article/DaVinci/TMS320DM81x/201408/52651.html

http://blog.csdn.net/xgmiao/article/details/23512021

http://www.cnblogs.com/jck34/p/3898569.html

http://blog.csdn.net/onion2007/article/details/46805335