YUV2RGB

#include 
#include 

using namespace  cv;
using namespace std;
//#include <>
#define nWidth 640
#define nHeight 480
#define FrameSize nWidth*nHeight*3/2

#define YUV2R(y, u, v) ({ \
	int r = (y) + ((((v) - 128) * 1436) >> 10); r > 255 ? 255 : r < 0 ? 0 : r; })
#define YUV2G(y, u, v) ({ \
	int g = (y) - ((((u) - 128) * 352 + ((v) - 128) * 731) >> 10); g > 255 ? 255 : g < 0 ? 0 : g; })
#define YUV2B(y, u, v) ({ \
	int b = (y) + ((((u) - 128) * 1814) >> 10); b > 255 ? 255 : b < 0 ? 0 : b; })

#define CLIP(color) (unsigned char)(((color) > 0xFF) ? 0xff : (((color) < 0) ? 0 : (color)))

void v4lconvert_yuv420_to_bgr24__(const unsigned char *src, unsigned char *dest,int width, int height, int yvu)
{
	int i, j;

	const unsigned char *ysrc = src;
	const unsigned char *usrc, *vsrc;

	if (yvu) 
	{
		vsrc = src + width * height;
		usrc = vsrc + (width * height) / 4;
	} else {
		usrc = src + width * height;
		vsrc = usrc + (width * height) / 4;
	}

	for (i = 0; i < height; i++) {
		for (j = 0; j < width; j += 2) {
#if 1 /* fast slightly less accurate multiplication free code */
			int u1 = (((*usrc - 128) << 7) +  (*usrc - 128)) >> 6;
			int rg = (((*usrc - 128) << 1) +  (*usrc - 128) +
				((*vsrc - 128) << 2) + ((*vsrc - 128) << 1)) >> 3;
			int v1 = (((*vsrc - 128) << 1) +  (*vsrc - 128)) >> 1;

			*dest++ = CLIP(*ysrc + u1);
			*dest++ = CLIP(*ysrc - rg);
			*dest++ = CLIP(*ysrc + v1);
			ysrc++;

			*dest++ = CLIP(*ysrc + u1);
			*dest++ = CLIP(*ysrc - rg);
			*dest++ = CLIP(*ysrc + v1);
#else
			*dest++ = YUV2B(*ysrc, *usrc, *vsrc);
			*dest++ = YUV2G(*ysrc, *usrc, *vsrc);
			*dest++ = YUV2R(*ysrc, *usrc, *vsrc);
			ysrc++;

			*dest++ = YUV2B(*ysrc, *usrc, *vsrc);
			*dest++ = YUV2G(*ysrc, *usrc, *vsrc);
			*dest++ = YUV2R(*ysrc, *usrc, *vsrc);
#endif
			ysrc++;
			usrc++;
			vsrc++;
		}
		/* Rewind u and v for next line */
		if (!(i & 1)) {
			usrc -= width / 2;
			vsrc -= width / 2;
		}
	}


}



int main()
{
 /*IplImage *img = cvLoadImage("D:\\workspace\\cv_yun\\DSC_1598.JPG");
 cvNamedWindow("a");
 cvShowImage("a",img);
 cvWaitKey(0);
 */

 FILE *f ;
 if(!(f = fopen("c:\\YUV420.yuv","rb")))
 {
  printf("file open error!");
 }

 // calculate the frame num
 fseek(f, 0, SEEK_END);
 int frame_count = 0;
 long file_size = 0;
 frame_count = (int) ((int)ftell(f)/((nWidth * nHeight * 3) / 2));  // ftell 用于求文件大小
 printf("frame num is %d \n", frame_count);
 printf("file length is   %d",ftell(f));

 fseek(f, 0, SEEK_SET);//文件内位置定位到文件头
 //IplImage *img = cvCreateImage(cvSize(352,288),IPL_DEPTH_8U,1);
 //IplImage *grey;
 for (int i=0;i<100;i++)
 {

 IplImage *yimg = cvCreateImage(cvSize(nWidth, nHeight),IPL_DEPTH_8U,1);
 //IplImage *uimg = cvCreateImageHeader(cvSize(nWidth/2, nHeight/2),IPL_DEPTH_8U,1);  
    //IplImage *vimg = cvCreateImageHeader(cvSize(nWidth/2, nHeight/2),IPL_DEPTH_8U,1);
 
 //----------------------------------------------------------------------实现读取一个文件 显示照片
 unsigned char *pBuf = new unsigned char[nWidth*nHeight*3/2];
 fread(pBuf, 1, (nWidth * nHeight * 3) / 2, f);// nWidth*nHeight*3/2  means 本程序使用 yuv:4:2:0 yuv分为 Y Cb Cr 三部分
 cvSetData(yimg, pBuf, nWidth);
 cvNamedWindow("a");
 cvShowImage("a", yimg);
 cvWaitKey( 1 );


  unsigned char *PRGB = new unsigned char[nWidth*nHeight*3];
  PRGB=(unsigned char*)malloc(nWidth*nHeight*3*sizeof(unsigned char));
   v4lconvert_yuv420_to_bgr24__(pBuf, PRGB,nWidth, nHeight, 24);


   Mat YUVDATA(Size(nWidth,nHeight),CV_8UC3,Scalar(0));

   memcpy(YUVDATA.data,PRGB,nWidth*nHeight*3);
   cvtColor(YUVDATA,YUVDATA,CV_BGR2RGB);
   imshow("YUVDATA",YUVDATA);
   waitKey(1);
   }
 //----------------------------------------------------------------------读取yuv文件的y部分 类似于播放器效果 
 /*unsigned char *pBuf = new unsigned char[nWidth*nHeight*3/2];
 int pos = 0;
 for(int i = 0; i