现在虚拟视点生成了yuv格式的视频流，如何计算每一帧的psnr值，进行了如下步骤：
1.对yuv视频流进行转换为jpg图片；
2.把jpg图片转化为avi视频流，便于批处理；
3.对avi视频中的每一帧计算psnr值。
程序：
- #include <stdlib.h>
- #include <stdio.h>
- #include <math.h>
- #include <cv.h>
- #include <highgui.h>
- #define NUM_FRAME 100 //只处理前100帧，根据视频帧数可修改
- void CalcPsnr(const char *in1,const char *in2)
- {
- cv::VideoCapture vc1;
- cv::VideoCapture vc2;
- bool flag1 = vc1.open(in1);
- bool flag2 = vc2.open(in2);
- if (!flag1||!flag2)
- {
- printf("avi file open error \n");
- system("pause");
- exit(-1);
- }
- int frmCount1 = vc1.get(CV_CAP_PROP_FRAME_COUNT);
- int frmCount2 = vc2.get(CV_CAP_PROP_FRAME_COUNT);
- printf("frmCount: %d \n", frmCount1);
- printf("frmCount: %d \n", frmCount2);
- for (int i = 0; i < frmCount1; i++)
- {
- printf("%d/%d \n", i + 1, frmCount1);
- cv::Mat image_ref;
- vc1 >> image_ref;
- cv::Mat image_obj;
- vc2 >> image_obj;
- double mse = 0;
- double div_r = 0;
- double div_g = 0;
- double div_b = 0;
- int width = image_ref.cols;
- int height = image_ref.rows;
- double psnr = 0;
- for (int v = 0; v < height; v++)
- {
- for (int u = 0; u < width; u++)
- {
- div_r = image_ref.at<cv::Vec3b>(v, u)[0] - image_obj.at<cv::Vec3b>(v, u)[0];
- div_g = image_ref.at<cv::Vec3b>(v, u)[1] - image_obj.at<cv::Vec3b>(v, u)[1];
- div_b = image_ref.at<cv::Vec3b>(v, u)[2] - image_obj.at<cv::Vec3b>(v, u)[2];
- mse += ((div_r*div_r + div_b*div_b + div_g*div_g) / 3);
- }
- }
- mse = mse / (width*height);
- psnr = 10 * log10(255 * 255 / mse);
- printf("%lf\n", mse);
- printf("%lf\n", psnr);
- }
- return;
- }
- void DisplayYUV2RGB(const char *dir,const char *in,int _w,int _h)
- {
- int w = _w;
- int h = _h;
- printf("yuv file w: %d, h: %d \n", w, h);
- FILE* pFileIn = fopen(in, "rb+");
- int bufLen = w*h * 3 / 2;
- unsigned char* pYuvBuf = new unsigned char[bufLen];
- int iCount = 0;
- for (int i = 0; i<NUM_FRAME; i++)
- {
- fread(pYuvBuf, bufLen*sizeof(unsigned char), 1, pFileIn);
- cv::Mat yuvImg;
- yuvImg.create(h * 3 / 2, w, CV_8UC1);
- memcpy(yuvImg.data, pYuvBuf, bufLen*sizeof(unsigned char));
- cv::Mat rgbImg;
- cv::cvtColor(yuvImg, rgbImg, CV_YUV2BGR_I420);
- cv::imshow("img", rgbImg);
- char s[100];
- sprintf(s,"%spic%d%s",dir,i,".jpg");
- cv::imwrite(s, rgbImg);
- cv::waitKey(1);
- printf("%d \n", iCount++);
- }
- delete[] pYuvBuf;
- fclose(pFileIn);
- }
- void Image_to_video(const char* in, const char* out)
- {
- int num = 1;
- CvSize size = cvSize(1024, 768); //视频帧格式的大小
- double fps = 30; //每秒钟的帧率
- CvVideoWriter *writer = cvCreateVideoWriter(out, CV_FOURCC('D', 'I', 'V', 'X'), fps, size); //创建视频文件
- char cname[100];
- sprintf(cname, in, num); //加载图片的文件夹，图片的名称编号是1开始1，2,3,4,5.。。。
- IplImage *src = cvLoadImage(cname);
- if (!src)
- {
- return;
- }
- IplImage *src_resize = cvCreateImage(size, 8, 3); //创建视频文件格式大小的图片
- cvNamedWindow("avi");
- while (src)
- {
- cvShowImage("avi", src_resize);
- cvWaitKey(1);
- cvResize(src, src_resize); //将读取的图片设置为视频格式大小相同
- cvWriteFrame(writer, src_resize); //保存图片为视频流格式
- cvReleaseImage(&src); //释放空间
- num++;
- sprintf(cname, in, num);
- src = cvLoadImage(cname); //循环读取数据
- }
- cvReleaseVideoWriter(&writer);
- cvReleaseImage(&src_resize);
- }
- int main(int argc, char *argv[])
- {
- const char *out = "C:/Users/jiang/Desktop/output/book_virtual08.yuv";
- const char *dir = "C:/Users/jiang/Desktop/output/tupian1/";
- DisplayYUV2RGB(dir, out, 1024, 768);
- const char *outImagename = "C:/Users/jiang/Desktop/output/tupian1/pic%d.jpg";
- const char *outVideoname = "C:/Users/jiang/Desktop/output/3outfile.avi";
- Image_to_video(outImagename, outVideoname);
- out = "C:/Users/jiang/Desktop/bookarrival/bookarrival_c_8.yuv";
- dir = "C:/Users/jiang/Desktop/output/tupian1/";
- DisplayYUV2RGB(dir, out, 1024, 768);
- outImagename = "C:/Users/jiang/Desktop/output/tupian1/pic%d.jpg";
- outVideoname = "C:/Users/jiang/Desktop/output/4outfile.avi";
- Image_to_video(outImagename, outVideoname);
- const char *in1 = "C:/Users/jiang/Desktop/output/3outfile.avi";
- const char *in2 = "C:/Users/jiang/Desktop/output/4outfile.avi";
- CalcPsnr(in1, in2);
- getchar();
- }