bmp文件转yuv420文件

/*
    bmp文件转yuv420文件程序
     vc2010 + opencv 2.4.4
    研究hevc时现有图像为bmp格式，HM中需要yuv420格式，网上没找到合适转换工具，就简单写了份转换代码
    zhuyh
    2013-06-08
*/

#include <opencv2/opencv.hpp>
#include <stdio.h>
#include <fstream>
#include <windows.h>
using namespace std;
using namespace cv;

void bmp2yuv420(Mat bmp, char *file_name);
void yuv4202bmp(const char* yuvname, int nHeight, int nWidth);

#define BOOT_CMD 1

int main(int argc, char* argv[])
{
#ifdef BOOT_CMD
	if(argc == 3)
	{
		if(!strcmp(&argv[1][strlen(argv[1]-4)], ".bmp"))
		{
			Mat bmp = imread(argv[1]);
			int yuvRows = bmp.rows*3/2;
			int yuvCols = bmp.cols;
			int yuvSize = yuvRows*yuvCols;
			Mat yuvmat(yuvRows, yuvCols, CV_8UC1);
			const int max_path = 200;
			char filename[max_path] = "";
			strcat(filename, "d:\\bmp2yuv420\\");
			strcat(filename, argv[2]);			
			bmp2yuv420(bmp, argv[2]);
			printf("convert bmp to yuv succ\n");			
		}
	}

	if(argc == 1)
	{
		char file_in[100];
		char file_out[100];
		printf("input bmp file name: ");
		scanf("%s",file_in);
		printf("input yuv file name: ");
		scanf("%s",file_out);
		Mat bmp = imread(file_in);
		bmp2yuv420(bmp, file_out);
		printf("convert bmp to yuv succ\n");
	}
#else

	Mat bmp = imread("bmp.bmp");
	imshow("bmp file", bmp);
	bmp2yuv420(bmp, "yuv.yuv");
#endif
	//等待按键
	waitKey();
	system("pause");
 
	return 1;
}

void bmp2yuv420(Mat bmp, char *file_name)
{
	if(bmp.empty()) return;
	int nHeight = bmp.rows;
	int nWidth = bmp.cols;
	
	//Mat rmat(nHeight, nWidth, CV_8UC1);
	//Mat gmat(nHeight, nWidth, CV_8UC1);
	//Mat bmat(nHeight, nWidth, CV_8UC1);

	Mat ymat(nHeight, nWidth, CV_8UC1);
	Mat umat(nHeight/2, nWidth/2, CV_8UC1);
	Mat vmat(nHeight/2, nWidth/2, CV_8UC1);
	Mat yuvmat(nHeight, nWidth, CV_8UC3);

	//unsigned char r,g,b;
	unsigned char y,u,v;

	cvtColor(bmp, yuvmat, CV_RGB2YCrCb);

	for(int i=0; i<nHeight; i++)
	{
		for(int j=0; j<nWidth; j++)
		{
			//b = bmp.at<Vec3b>(i,j)[0];
			//g = bmp.at<Vec3b>(i,j)[1];
			//r = bmp.at<Vec3b>(i,j)[2];

			//rmat.at<unsigned char>(i,j) = r;
			//gmat.at<unsigned char>(i,j) = g;
			//bmat.at<unsigned char>(i,j) = b;

			y = yuvmat.at<Vec3b>(i,j)[0];
			ymat.at<unsigned char>(Point(j,i)) = y;
			if((i%2==0) && (j%2==0))
			{
				u = yuvmat.at<Vec3b>(i,j)[1];
				v = yuvmat.at<Vec3b>(i,j)[2];
				umat.at<unsigned char>(Point(j/2,i/2)) = u;
				vmat.at<unsigned char>(Point(j/2,i/2)) = v;
			}
		}
	}

	//显式
	//imshow("bmp2yuv420_rgb", bmp);
	//imshow("bmp2yuv420_r", rmat);
	//imshow("bmp2yuv420_g", gmat);
	//imshow("bmp2yuv420_b", gmat);

	//保存
	//imwrite("bmp2yuv420_rgb.bmp",bmp);
	//imwrite("bmp2yuv420_r.bmp",rmat);
	//imwrite("bmp2yuv420_g.bmp",gmat);
	//imwrite("bmp2yuv420_b.bmp",bmat);

	//显式
	//imshow("bmp2yuv420_y", ymat);
	//imshow("bmp2yuv420_u", umat);
	//imshow("bmp2yuv420_v", vmat);

	//保存
	//imwrite("bmp2yuv420_y.bmp", ymat);
	//imwrite("bmp2yuv420_u.bmp", umat);
	//imwrite("bmp2yuv420_v.bmp", vmat);

	int ySize = nWidth * nHeight;
	int uSize = ySize / 4;
	int vSize = ySize / 4;

	//const char* yuvname = "d:\yuv.yuv";
	const char* yuvname = file_name;
	fstream bitstreamFile(yuvname, ios::binary | ios::out);
	if(bitstreamFile.fail()) printf("open fail\n");

	bitstreamFile.write((char*)(ymat.data), ySize);
	if(bitstreamFile.fail() || bitstreamFile.eof())	printf("wirte fail\n");
	bitstreamFile.write((char*)(umat.data), uSize);
	if(bitstreamFile.fail() || bitstreamFile.eof())	printf("wirte fail\n");
	bitstreamFile.write((char*)(vmat.data), vSize);
	if(bitstreamFile.fail() || bitstreamFile.eof())	printf("wirte fail\n");
	printf("write yuv file succ\n");
}