YUV422与RGB互相转换

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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)

  1 #ifndef _RGB2YUV__ 
  2 #define _RGB2YUV__ 
  3 #include <iostream> 
  4 using namespace std; 
  5  
  6 #define TUNE(r) ( r < 0 ? 0 : (r > 255 ? 255 : r) ) 
  7  
  8 static  int RGB_Y[256]; 
  9 static  int RGBR_V[256]; 
 10 static  int RGBG_U[256]; 
 11 static  int RGBG_V[256]; 
 12 static  int RGBB_U[256]; 
 13  
 14  
 15 static  int YUVY_R[256]; 
 16 static  int YUVY_G[256]; 
 17 static  int YUVY_B[256]; 
 18  
 19 static  int YUVU_R[256]; 
 20 static  int YUVU_G[256]; 
 21 static  int YUVU_B[256]; 
 22  
 23 static  int YUVV_R[256]; 
 24 static  int YUVV_G[256]; 
 25 static  int YUVV_B[256]; 
 26  
 27 static int coff_rv[256]; 
 28 static int coff_gu[256]; 
 29 static int coff_gv[256]; 
 30 static int coff_bu[256]; 
 31  
 32 //直接采用公式浮点计算方式 
 33 //仅RGB2YUV采用了查表法,所以有一部分表是没有用到的 
 34 void InitTable() 
 35 { 
 36     int i; 
 37     for(i = 0;i<256;i++) 
 38     { 
 39         //初始化表,放大256倍 
 40         RGB_Y[i] = 298 * (i - 16); 
 41         RGBR_V[i] = 408 * (i - 128); 
 42         RGBG_U[i] = 100 * (128- i); 
 43         RGBG_V[i]= 208*(128-i); 
 44         RGBB_U[i] =517 * (i - 128); 
 45         //y=0.257*r+0.504*g+0.098*b+16 
 46         //u = -0.148*r - 0.291*g + 0.439*b + 128 
 47         //0.439*r - 0.368*g - 0.071*b + 128 
 48         YUVY_R[i]=66*i; 
 49         YUVY_G[i]=129*i; 
 50         YUVY_B[i]=25*i; 
 51         YUVU_R[i]=-38*i; 
 52         YUVU_G[i]=-74*i; 
 53         YUVU_B[i]=112*i; 
 54         YUVV_R[i]=112*i; 
 55         YUVV_G[i]=-94*i; 
 56         YUVV_B[i]=-18*i; 
 57        /*所用公式(此公式不适用)
 58         *pRGB = (unsigned char)(1.0*y + 8 + 1.402*(v-128));    pRGB++;                 // r
 59         *pRGB = (unsigned char)(1.0*y - 0.34413*(u-128) - 0.71414*(v-128));  pRGB++;   // g
 60         *pRGB = (unsigned char)(1.0*y + 1.772*(u-128) + 0);    pRGB++ ;  
 61         */ 
 62         coff_rv[i] = (8+1.402*(i-128))*256; 
 63         coff_gu[i] = -0.34413*(i-128)*256; 
 64         coff_gv[i] = -0.71414*(i-128)*256; 
 65         coff_bu[i] = 1.772*(i-128)*256; 
 66  
 67         /*应该使用如下公式:
 68 Y’ = 0.257*R\' + 0.504*G\' + 0.098*B\' + 16
 69 Cb\' = -0.148*R\' - 0.291*G\' + 0.439*B\' + 128
 70 Cr\' = 0.439*R\' - 0.368*G\' - 0.071*B\' + 128(标红的两组公式是可逆的转换)
 71 R\' = 1.164*(Y’-16) + 1.596*(Cr\'-128)
 72 G\' = 1.164*(Y’-16) - 0.813*(Cr\'-128) - 0.392*(Cb\'-128)
 73 B\' = 1.164*(Y’-16) + 2.017*(Cb\'-128)
 74 */ 
 75     } 
 76 } 
 77  
 78 void YUV2RGB422(unsigned char *pRGB, unsigned char *pYUV,int size) 
 79 { 
 80     unsigned char y, u, v,y1; 
 81     int r,g,b; 
 82     unsigned int i=0; 
 83     unsigned int loop = size>>1; 
 84     while(loop-- >0) 
 85     { 
 86          
 87         y = *pYUV; pYUV++; 
 88         u = *pYUV; pYUV++; 
 89         y1 = *pYUV;pYUV++; 
 90         v = *pYUV; pYUV++; 
 91      
 92         r = 1.164*(y-16) + 1.596*(v-128); 
 93         g = 1.164*(y-16) - 0.813*(v-128) - 0.392*(u-128); 
 94         b = 1.164*(y-16) + 2.017*(u-128); 
 95  
 96         *pRGB = TUNE(r);pRGB++; 
 97         *pRGB = TUNE(g);pRGB++; 
 98         *pRGB = TUNE(b);pRGB++; 
 99  
100          r = 1.164*(y1-16) + 1.596*(v-128); 
101          g = 1.164*(y1-16) - 0.813*(v-128) - 0.392*(u-128); 
102          b = 1.164*(y1-16) + 2.017*(u-128); 
103          *pRGB = TUNE(r);pRGB++; 
104          *pRGB = TUNE(g);pRGB++; 
105          *pRGB = TUNE(b);pRGB++; 
106      } 
107   
108  }
109  
110  //size 为图片的大小 
111  void RGB2YUV422(unsigned char *pRGB, unsigned char *pYUV,int size) 
112  { 
113      unsigned char r,g,b,u,v,u1,v1,r1,g1,b1; 
114      //unsigned char *YUVBuff; 
115      //unsigned char* p; 
116      //p = YUVBuff;// 
117      int loop = size/2; 
118      int i; 
119      for( i=0;i<loop;i++) 
120      { 
121          r = *pRGB; pRGB++; 
122          g = *pRGB; pRGB++; 
123          b = *pRGB; pRGB++; 
124          r1 = *pRGB; pRGB++; 
125          g1 = *pRGB; pRGB++; 
126          b1 = *pRGB; pRGB++; 
127           
128          //new method ---  right 
129          int y = ((YUVY_R[r] + YUVY_G[g] + YUVY_B[b] + 128) >> 8) +16;      
130          u = ((YUVU_R[r] + YUVU_G[g] + YUVU_B[b] + 128) >> 8) + 128; 
131          v = ((YUVV_R[r] + YUVV_G[g] + YUVV_B[b] + 128) >> 8) + 128; 
132          int y1 = ((YUVY_R[r1] + YUVY_G[g1] + YUVY_B[b1] + 128) >> 8)+16; 
133          u1 = ((YUVU_R[r1] + YUVU_G[g1] + YUVU_B[b1] + 128) >> 8) + 128; 
134          v1 = ((YUVV_R[r1] + YUVV_G[g1] + YUVV_B[b1] + 128) >> 8) + 128; 
135           
136          *pYUV++ = TUNE(y); 
137          *pYUV++ =(TUNE(u)+TUNE(u1))>>1; 
138          *pYUV++ = TUNE(y1); 
139          *pYUV++ = TUNE(v); 
140      }    
141       
142  } 
143   
144  void inline Yuv2RgbPixel(unsigned char y,unsigned char u,unsigned char v, unsigned char* rgbPixel) 
145  { 
146      int r = (RGB_Y[y] + RGBR_V[v] + 128) >> 8; 
147      int g = ((RGB_Y[y] + RGBG_V[v]  +RGBG_U[u]+ 128)>>8 ); 
148      int b = ((RGB_Y[y] + RGBB_U[u]+128 )>>8);  
149      *rgbPixel=TUNE(r);rgbPixel++; 
150      *rgbPixel=TUNE(g);rgbPixel++; 
151      *rgbPixel=TUNE(b); 
152  }
153  
154  void YUV2RGB(unsigned char *pRGB, unsigned char *pYUV,int size)//444 
155  { 
156      unsigned char y, u, v; 
157   
158      for(int i=0;i<size;i++) 
159      { 
160          y = *pYUV; pYUV++; 
161          u = *pYUV; pYUV++; 
162          v = *pYUV; pYUV++; 
163   
164          Yuv2RgbPixel(y,u,v,pRGB); 
165          pRGB += 3; 
166      } 
167       
168  } 
169  
170  void inline Rgb2YuvPiexl(unsigned char r,unsigned char g,unsigned char b,unsigned char* pYUV) 
171  { 
172      int y = ((YUVY_R[r] + YUVY_G[g] + YUVY_B[b] + 128) >> 8) + 16;      
173      int u = ((YUVU_R[r] + YUVU_G[g] + YUVU_B[b] + 128) >> 8) + 128; 
174      int v = ((YUVV_R[r] + YUVV_G[g] + YUVV_B[b] + 128) >> 8) + 128; 
175      *pYUV = TUNEY(y);pYUV++; 
176          //*pYUV = u < 0 ? 0 : (u > 255 ? 255 : u);pYUV++;  
177      *pYUV =TUNE(u);pYUV++; 
178      *pYUV = TUNE(v); 
179  } 
180  
181  void RGB2YUV(unsigned char *pRGB, unsigned char *pYUV,int size) 
182  { 
183      unsigned char r,g,b,y,u,v; 
184      for(int i=0;i<size;i++) 
185      { 
186          r = *pRGB; pRGB++; 
187          g = *pRGB; pRGB++; 
188          b = *pRGB; pRGB++; 
189          Rgb2YuvPiexl(r,g,b,pYUV); 
190          pYUV +=3; 
191   
192      }    
193  } 
194  #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

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