YUV格式转换为RGB（基于opencv）

之前写代码过程中需要将YUV格式视频中每帧提取出来，然后保存为图片。网上普遍有两种方法，第一种是通过opencv自带cvCvtColor，但是这种方法有bug，得到的图片会泛白。第二种方法是公式法。

法一：opencv自带cvCvtColor

说明：这种方法会出现图片“泛白”，具体原因网上是说cvCvtColor这个函数左右协议不同，不太懂。

代码：

 

 void FileWriteFrames(){
     char *filename = "E:\\openCV\\zhang\\yuvSource\\football_cif.yuv";
     ifstream readMe(filename, ios::in | ios::binary);  // 打开并读yuv数据
     IplImage *image, *rgbimg, *yimg, *uimg, *vimg, *uuimg, *vvimg;
     cvNamedWindow("yuv",CV_WINDOW_AUTOSIZE);
     rgbimg = cvCreateImage(cvSize(ISizeX, ISizeY), IPL_DEPTH_8U, 3);
     image = cvCreateImage(cvSize(ISizeX, ISizeY), IPL_DEPTH_8U, 3);

     yimg = cvCreateImageHeader(cvSize(ISizeX, ISizeY), IPL_DEPTH_8U, 1);    // 亮度分量
     uimg = cvCreateImageHeader(cvSize(ISizeX/2, ISizeY/2), IPL_DEPTH_8U, 1);  // 这两个都是色度分量
     vimg = cvCreateImageHeader(cvSize(ISizeX/2, ISizeY/2), IPL_DEPTH_8U, 1);

     uuimg = cvCreateImage(cvSize(ISizeX, ISizeY), IPL_DEPTH_8U, 1);
     vvimg = cvCreateImage(cvSize(ISizeX, ISizeY), IPL_DEPTH_8U, 1);
     int nframes;
     for(nframes = 0; nframes < FCount; nframes ++){
         char nframesstr[20];
         readMe.read((char*)Y[nframes],ISizeX*ISizeY);
         //readMe.seekg(-ISizeX*ISizeY, ios::cur);
         //readMe.read((char*)buf[nframes],ISizeX*ISizeY+ISizeX/2*ISizeY/2+ISizeX/2*ISizeY/2);
         readMe.read((char*)buf[nframes],ISizeX/2*ISizeY/2);
         readMe.read((char*)buf2[nframes],ISizeX/2*ISizeY/2);
         cvSetData(yimg,Y[nframes],ISizeX);
         //cvSetData(uimg,buf[nframes] + ISizeX*ISizeY, ISizeX/2);
         cvSetData(uimg,buf[nframes], ISizeX/2);
         cvSetData(vimg,buf2[nframes], ISizeX/2);


         cvResize(uimg,uuimg, CV_INTER_LINEAR);
         cvResize(vimg,vvimg, CV_INTER_LINEAR);
         cvMerge(yimg,uuimg,vvimg,NULL,image);   // 合并单通道为三通道
         cvCvtColor(image,rgbimg,CV_YUV2BGR);

         stringstream ss;  // 类型转换统一转换为char* 类型
         ss << nframes;
         ss << ".jpg" ;
         ss >> nframesstr;
         cvShowImage("yuv", rgbimg);
         cvSaveImage(nframesstr,rgbimg);
         int c = cvWaitKey(30);
         if((char)c == 27)
         {
             break;
         }
     }
     readMe.close();
     cvReleaseImage(&uuimg);
     cvReleaseImage(&vvimg);
     cvReleaseImageHeader(&yimg);
     cvReleaseImageHeader(&uimg);
     cvReleaseImageHeader(&vimg);
     cvReleaseImage(&image);
     cvDestroyWindow("yuv");
 }

法二：公式法

代码：

 bool YUV420_To_BGR24(unsigned char *puc_y, unsigned char *puc_u, unsigned char *puc_v, unsigned char *puc_rgb, int width_y, int height_y)
 {
     if (!puc_y || !puc_u || !puc_v || !puc_rgb)
     {
         return false;
     }

     //初始化变量
     int baseSize = width_y * height_y;
     int rgbSize = baseSize * 3;

     BYTE* rgbData  = new BYTE[rgbSize];
     memset(rgbData, 0, rgbSize);

     /* 变量声明 */
     int temp = 0;

     BYTE* rData = rgbData;                  //r分量地址
     BYTE* gData = rgbData + baseSize;       //g分量地址
     BYTE* bData = gData   + baseSize;       //b分量地址

     int uvIndex =0, yIndex =0;

     //YUV->RGB 的转换矩阵
     //double  Yuv2Rgb[3][3] = {1, 0, 1.4022,
     //    1, -0.3456, -0.7145,
     //    1, 1.771,   0};

     for(int y=0; y < height_y; y++)
     {
         for(int x=0; x < width_y; x++)
         {
             uvIndex        = (y>>1) * (width_y>>1) + (x>>1);
             yIndex         = y * width_y + x;

             /* r分量 */
             temp          = (int)(puc_y[yIndex] + (puc_v[uvIndex] - 128) * 1.4022);
             rData[yIndex] = temp<0 ? 0 : (temp > 255 ? 255 : temp);

             /* g分量 */
             temp          = (int)(puc_y[yIndex] + (puc_u[uvIndex] - 128) * (-0.3456) +
                 (puc_v[uvIndex] - 128) * (-0.7145));
             gData[yIndex] = temp < 0 ? 0 : (temp > 255 ? 255 : temp);

             /* b分量 */
             temp          = (int)(puc_y[yIndex] + (puc_u[uvIndex] - 128) * 1.771);
             bData[yIndex] = temp < 0 ? 0 : (temp > 255 ? 255 : temp);
         }
     }

     //将R,G,B三个分量赋给img_data
     int widthStep = width_y*3;
     for (int y = 0; y < height_y; y++)
     {
         for (int x = 0; x < width_y; x++)
         {
             puc_rgb[y * widthStep + x * 3 + 2] = rData[y * width_y + x];   //R
             puc_rgb[y * widthStep + x * 3 + 1] = gData[y * width_y + x];   //G
             puc_rgb[y * widthStep + x * 3 + 0] = bData[y * width_y + x];   //B
         }
     }

     if (!puc_rgb)
     {
         return false;
     }
     delete [] rgbData;
     return true;
 }

 IplImage* YUV420_To_IplImage(unsigned char* pYUV420, int width, int height)
 {
     if (!pYUV420)
     {
         return NULL;
     }

     //初始化变量
     int baseSize = width*height;
     int imgSize = baseSize*3;
     BYTE* pRGB24  = new BYTE[imgSize];
     memset(pRGB24,  0, imgSize);

     /* 变量声明 */
     int temp = 0;

     BYTE* yData = pYUV420;                  //y分量地址
     BYTE* uData = pYUV420 + baseSize;       //u分量地址
     BYTE* vData = uData  + (baseSize>>2);   //v分量地址

     if(YUV420_To_BGR24(yData, uData, vData, pRGB24, width, height) == false || !pRGB24)
     {
         return NULL;
     }

     IplImage *image = cvCreateImage(cvSize(width, height), 8,3);
     memcpy(image->imageData, pRGB24, imgSize);

     if (!image)
     {
         return NULL;
     }

     delete [] pRGB24;
     return image;
 }

 void FileWriteFrames(){
     char *filename = "E:\\openCV\\zhang\\yuvSource\\FOOTBALL_352x288_30_orig_01.yuv";
     ifstream readMe(filename, ios::in | ios::binary);  // 打开并读yuv数据
     int nframes;
     for(nframes = 0; nframes < FCount; nframes ++){
         char nframesstr[20];
         readMe.read((char*)Y[nframes],ISizeX*ISizeY);
         readMe.seekg(-ISizeX*ISizeY, ios::cur);
         readMe.read((char*)buf[nframes],ISizeX*ISizeY+ISizeX/2*ISizeY/2+ISizeX/2*ISizeY/2);
         IplImage *rgbimg = YUV420_To_IplImage(buf[nframes], ISizeX, ISizeY);
         stringstream ss;  // 类型转换统一转换为char* 类型
         ss << nframes;
         ss << ".jpg" ;
         ss >> nframesstr;
         cvShowImage("yuv", rgbimg);
         cvSaveImage(nframesstr,rgbimg);
         int c = cvWaitKey(30);
         if((char)c == 27)
         {
             break;
         }
     }
     readMe.close();
 }

完整代码见：http://download.csdn.net/detail/lu597203933/7362687

参见blog：http://blog.csdn.net/dreamd1987/article/details/7259479#