YUV格式转换为RGB（基于opencv）

雨点打透心脏的1/2处 2022-08-26 14:22 347阅读 0赞

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\#