OpenCV 学习笔记（13）图像转换成视频

关键

1参数里的分辨率是图像本身的分辨率，而不是指定生成的视频分辨率。如果要修改分辨率，要么后期软件处理，要么读图的时候resize

2要正常退出，不要强制退出。

3生成的只能是avi格式。

#include <iostream>
#include <string>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/core/core.hpp"
#include "opencv2/opencv.hpp"

using namespace std;
using namespace cv;
void  Video_To_Image(string filename);
void  Image_To_Video();
int imagetovideo();
int main()
{
	//string video_name = "test.avi";//注意，使用string时，若不用using namespace std，需要使用std::string
	//Video_To_Image(video_name);
	Image_To_Video();
	//imagetovideo();
	return 0;
}


void Video_To_Image(string filename)
{
	cout << "---------------Video_To_Image-----------------" << endl;
	cv::VideoCapture capture(filename);
	if (!capture.isOpened())
	{
		cout << "open video error";
	}
	/*CV_CAP_PROP_POS_MSEC – 视频的当前位置（毫秒）
	CV_CAP_PROP_POS_FRAMES – 视频的当前位置（帧）
	CV_CAP_PROP_FRAME_WIDTH – 视频流的宽度
	CV_CAP_PROP_FRAME_HEIGHT – 视频流的高度
	CV_CAP_PROP_FPS – 帧速率（帧 / 秒）*/
	int frame_width = (int)capture.get(CV_CAP_PROP_FRAME_WIDTH);
	int frame_height = (int)capture.get(CV_CAP_PROP_FRAME_HEIGHT);
	float frame_fps = capture.get(CV_CAP_PROP_FPS);
	int frame_number = capture.get(CV_CAP_PROP_FRAME_COUNT);//总帧数
	cout << "frame_width is " << frame_width << endl;
	cout << "frame_height is " << frame_height << endl;
	cout << "frame_fps is " << frame_fps << endl;

	int num = 0;//统计帧数
	cv::Mat img;
	string img_name;
	char image_name[20];
	cv::namedWindow("MyVideo", CV_WINDOW_AUTOSIZE);
	while (true)
	{
		cv::Mat frame;
		//从视频中读取一个帧
		bool bSuccess = capture.read(frame);
		if (!bSuccess)
		{
			cout << "不能从视频文件读取帧" << endl;
			break;
		}
		//在MyVideo窗口上显示当前帧
		imshow("MyVideo", frame);
		//保存的图片名
		//sprintf(const_cast<char*>(img_name.data()), "%s%d%s", "image", ++num, ".jpg");//保存的图片名
		sprintf(image_name, "%s%d%s", "image", ++num, ".jpg");//保存的图片名
		img_name = image_name;
		imwrite(img_name, frame);//保存保存一帧图片
		if (cv::waitKey(30) == 27 || num == frame_number)
		{
			cout << "按下ESC键" << endl;
			break;
		}
	}
	capture.release();//这句话貌似不需要
}



void Image_To_Video()
{
	cout << "---------------Video_To_Image-----------------" << endl;
	
	string s_image_name;
	cv::VideoWriter writer;
	int isColor = 1;//不知道是干啥用的
	int frame_fps = 25;
	int frame_width = 1920;   //必须是图像真实的分辨率，这不是指定生成视频的分辨率
	int frame_height = 1080;

	string video_name = "out.avi";
	//CV_FOURCC('M', 'J', 'P', 'G')   CV_FOURCC('D', 'I', 'V', 'X')
	writer = VideoWriter(video_name, CV_FOURCC('D', 'I', 'V', 'X'), frame_fps, Size(frame_width, frame_height), isColor);
	cout << "frame_width is " << frame_width << endl;
	cout << "frame_height is " << frame_height << endl;
	cout << "frame_fps is " << frame_fps << endl;
	cv::namedWindow("image to video", CV_WINDOW_AUTOSIZE);
	int num = 50;//输入的图片总张数
	int i = 1;
	Mat img;


	if (!writer.isOpened())
	{
		cout << "Error : fail to open video writer
" << endl;
		return ;
	}


	while (i <= num)
	{
		string path = "F:/dongdong/1学习资料/1论文/2发表/稠密轨迹跟踪/最新论文/代码/0数据/光流跟踪/result/test2/2GUI/1/";
		s_image_name = path + std::to_string(i++) + ".jpg";
		img = imread(s_image_name);//读入图片
		if (!img.data)//判断图片调入是否成功
		{
			cout << "Could not load image file...
" << endl;
			
			break;
		}
		//imshow();
		//写入
		
		writer << img;

		imshow("image to video", img);
		waitKey(1);

		if (cv::waitKey(30) == 27 || i == num)
		{
			cout << "按下ESC键" << endl;
			cvReleaseVideoWriter;
			break;
		}
	}
	cvReleaseVideoWriter;
}