视频合并；将两个视频合并为一个文件，并在视频中打标签

      #include <iostream>
#include <opencv2/opencv.hpp>
#include <unistd.h>
#include <error.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <pthread.h>
#include <linux/videodev2.h>
#include <sys/mman.h>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
using namespace cv;



int main(int argc, char ** argv)
{

    std::string videoFile = "top_view.mp4";//视频的路径
    std::string videoFile1 = "fusion_view.mp4";//视频的路径
    
    /** 打开第一个视频文件 */
    VideoCapture cap; //视频句柄变量
    cap.open(videoFile);//打开视频
    if(!cap.isOpened())  //判断是否打开了
    {  
        printf("cap.isOpened is error\n");
        return -1;  
    } 
    
    /** 打开第二个视频文件 */
    VideoCapture cap1; //视频句柄变量
    cap1.open(videoFile1);//打开视频
    if(!cap1.isOpened())  //判断是否打开了
    {  
        printf("cap.isOpened is error\n");
        return -1;  
    } 
    
    
    /** 打开第一个视频文件的帧数 */
    int frame_num = cap.get(cv::CAP_PROP_FRAME_COUNT);
	std::cout << "videoFile total frame number is: " << frame_num << std::endl;
	/** 打开第二个视频文件的帧数 */
	int frame_num1 = cap1.get(cv::CAP_PROP_FRAME_COUNT);
	std::cout << "videoFile1 total frame number is: " << frame_num1 << std::endl;
	
	/** 打开第一个视频文件的帧率 */
    int fps = cap.get(cv::CAP_PROP_FPS);
	std::cout << "videoFile fps: " << fps << std::endl;
	/** 打开第二个视频文件的帧率 */
	int fps1 = cap1.get(cv::CAP_PROP_FPS);
	std::cout << "videoFile1 fps1: " << fps1 << std::endl;
	
	
	 /** 打开第一个视频文件的宽度 */
    int image_width = cap.get(cv::CAP_PROP_FRAME_WIDTH);
	std::cout << "videoFile image width is: " << image_width << std::endl;
	/** 打开第二个视频文件的宽度 */
	int image_width1 = cap1.get(cv::CAP_PROP_FRAME_WIDTH);
	std::cout << "videoFile1 image width is: " << image_width1 << std::endl;
	
	/** 打开第一个视频文件的高度 */
    int image_height = cap.get(cv::CAP_PROP_FRAME_HEIGHT);
	std::cout << "videoFile image height: " << image_height << std::endl;
	/** 打开第二个视频文件的高度 */
	int image_height1 = cap1.get(cv::CAP_PROP_FRAME_HEIGHT);
	std::cout << "videoFile1 image height: " << image_height1 << std::endl;
	

    /** 打开第一个视频文件的矩阵对象的格式*/
     int frame_format = cap.get(cv::CAP_PROP_FORMAT);
	std::cout << "videoFile frame format: " << frame_format << std::endl;
	/** 打开第二个视频文件的矩阵对象的格式 */
	int frame_format1 = cap1.get(cv::CAP_PROP_FORMAT);
	std::cout << "videoFile1 image height: " << frame_format1 << std::endl;

	
	/** 合并视频初始化 */
	std::string mergeVideooFile = "mergeVideo.avi";
	int mergeVideooHeight = 600;
	int mergeVideooWidth = 1250;
	float mergeVideooFps = 10.0;
	int mergeVideooFpsFrameFormat = CV_8UC3;
	
	/*
	mergeVideooHeight = image_height + image_height1 + 10;
	mergeVideooWidth = image_width + image_width1 + 10;
	mergeVideooFps = fps;
	if(fps1>fps)
	    mergeVideooFps = fps1;
    mergeVideooFps = 10;
    mergeVideooFpsFrameFormat = frame_format;
	*/
	cv::VideoWriter track_writer;
    Mat img = cv::Mat::zeros(mergeVideooWidth, mergeVideooHeight, mergeVideooFpsFrameFormat);
    track_writer.open (mergeVideooFile, cv::VideoWriter::fourcc('M', 'P', '4', '2'), mergeVideooFps, cv::Size(mergeVideooWidth, mergeVideooHeight));
    if(!track_writer.isOpened())
    {
        assert("track writer open failed!\n");
    }
    
    


    Mat frame; 
    Mat frame1;
   
    while(1)
    {
        cap.read(frame);//从第一个视频获取一帧图片
        cap1.read(frame1);//从第二个视频获取一帧图片
        if(frame.empty()) break; //是否加载成功


        //std::cout << "Width : " << frame1.cols << std::endl;
        //std::cout << "Height: " << frame1.rows << std::endl;
        // std::cout << "Width : " << frame.cols << std::endl;
        //std::cout << "Height: " << frame.rows << std::endl;
        //cout << "======================"  << endl;
        
        
        // 设定ROI区域：截取一部分进行合并
        Mat imageROI= frame(Rect(400,0,400,600));
        Mat imageROI1= frame1(Rect(200,0,850,450));
       
        // 大小转换
        Mat imageROI1dst = Mat::zeros(600,850 , CV_8UC3); //我要转化为850*600大小的
	    resize(imageROI1, imageROI1dst, imageROI1dst.size());
   
      
        // 视频写字
        putText(imageROI1dst, videoFile, Point(5, 55),FONT_HERSHEY_PLAIN,2.0,(0, 255, 255),2);
        putText(imageROI, videoFile1, Point(5, 55),FONT_HERSHEY_PLAIN,2.0,(0, 255, 255),2);
      
         
        //创建目标Mat
        Mat des;
        des.create(mergeVideooHeight,mergeVideooWidth, imageROI1dst.type());
        // 视频帧合并
        Mat r1 = des(Rect(0, 0, 850, 600));
        imageROI1dst.copyTo(r1);
        Mat r2 = des(Rect(850, 0, 400, 600));
        imageROI.copyTo(r2);
        
        // 格式化要保存的视频帧
        cv::resize(des, img , cv::Size(mergeVideooWidth, mergeVideooHeight));
        // 保存视频
        track_writer.write(img);
        
        
        
        // 可视化
        imshow("mergeVideoo",des);
        if (cv::waitKey(30) == 'q')//可以用开控制播放或者获取图片的速度，毫秒级别
		{
			break;
		}
    }
    
    
    destroyWindow("mergeVideoo");//关闭窗口bb；
    destroyAllWindows();//关闭所有的窗口
    cap.release();//释放视频句柄
    
    track_writer.release();
	return 0;
}