opencv yuvNV21转RGB

void yuv420Torgb()
{
FILE *fp = fopen("D:\\1.yuv","rb");
int width = ;
int height = ;
uchar *yuvdata = new uchar[height *  /  * width * sizeof(uchar)];
fread(yuvdata, height *  / , width, fp);
Mat yuvimg(height *  / , width, CV_8UC1, yuvdata);
Mat rgbimg(height, width, CV_8UC3);
cvtColor(yuvimg, rgbimg, COLOR_YUV2BGR_NV21);
namedWindow("src", );
imshow("src", rgbimg);
waitKey();
fclose(fp);
delete[] yuvdata;
}