《随堂小记》 OPENCV+获取视频中某一帧的图像并保存

// GetApictureOfVideos.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "string"
#include <iostream>//io流  cout
#include <opencv2/highgui/highgui.hpp>//添加此句不出错说明安装配置成功
#include <time.h>

using namespace std;
using namespace cv;
void Video_to_Image(string filename)
{
VideoCapture capture(filename);//获取VideoCapture 对象
if (!capture.isOpened())
{
cout << "open video error";
}
//capture.get十分强大 可以获得帧的很多信息
int frame_width = (int)capture.get(CAP_PROP_FRAME_WIDTH);
int frame_height = (int)capture.get(CAP_PROP_FRAME_HEIGHT);
int frame_number = capture.get(CAP_PROP_FRAME_COUNT);
cout << "frame_width is " << frame_width << endl;
cout << "frame_height is " << frame_height << endl;
cout << "frame_number is " << frame_number << endl;
srand((unsigned)time(NULL));#时间点
long frameToStart = rand() % frame_number;#取  最大帧数之内的 随机数
cout <<"帧开始的地方"<< frameToStart << endl;
capture.set(CAP_PROP_POS_FRAMES, frameToStart);//从此时的帧数开始获取帧

Mat frame; #Mat对象  其实就是图像对象
char image_name[20];
if (!capture.read(frame))
{
cout << "读取视频失败" << endl;
}
imshow("che", frame);//显示
sprintf(image_name, "%s%s", "image", ".jpg");//保存的图片名
imwrite(image_name, frame);#写入  前面是  path+name不要忘了后缀 后面是 帧

capture.release();#释放对象

}
int main()
{
string filename = "F:/1.mp4";
Video_to_Image(filename);
waitKey(0);
return 0;
}