YUV422与RGB互相转换

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 <iostream>
 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