视频剪切成图像保存到本地

版权声明：guojawee https://blog.csdn.net/weixin_36750623/article/details/84782614

#include<opencv2\opencv.hpp>
#include <iostream>
#include <stdio.h>
#include<fstream> 

using namespace std;
using namespace cv;

//获取视频中的人脸

int main()
{
	//打开视频文件：其实就是建立一个VideoCapture结构  
	VideoCapture capture("G:\\test3.mp4");
	//检测是否正常打开:成功打开时，isOpened返回ture  
	if (!capture.isOpened())
		cout << "fail toopen!" << endl;

	//获取整个帧数  
	long totalFrameNumber = capture.get(CV_CAP_PROP_FRAME_COUNT);
	cout << "整个视频共" << totalFrameNumber << "帧" << endl;
	//设置开始帧()  
	long frameToStart = 1;
	capture.set(CV_CAP_PROP_POS_FRAMES, frameToStart);
	cout << "从第" << frameToStart << "帧开始读" << endl;


	//设置结束帧  
	int frameToStop = totalFrameNumber;

	if (frameToStop < frameToStart)
	{
		cout << "结束帧小于开始帧，程序错误，即将退出！" << endl;
		return -1;
	}
	else
	{
		cout << "结束帧为：第" << frameToStop << "帧" << endl;
	}

	//获取帧率  
	double rate = capture.get(CV_CAP_PROP_FPS);
	cout << "帧率为:" << rate << endl;
	//定义一个用来控制读取视频循环结束的变量  
	bool stop = false;

	//承载每一帧的图像  
	Mat frame;

	//显示每一帧的窗口  
	namedWindow("Extractedframe");

	//两帧间的间隔时间:  
	//int delay = 1000/rate;  
	double delay = 1000 / rate;


	//利用while循环读取帧  
	//currentFrame是在循环体中控制读取到指定的帧后循环结束的变量  
	long currentFrame = frameToStart;


	//滤波器的核  
	int kernel_size = 3;
	Mat kernel = Mat::ones(kernel_size, kernel_size, CV_32F) / (float)(kernel_size*kernel_size);

	while (!stop)
	{
		//读取下一帧  
		if (!capture.read(frame))
		{
			cout << "读取视频失败" << endl;
			return -1;
		}


		cout << "正在读取第" << currentFrame << "帧" << endl;
		imshow("Extractedframe", frame);

		cout << "正在写第" << currentFrame << "帧" << endl;
		stringstream str;
		str << "G:\\1\\" << currentFrame << ".jpg";
		cout << str.str() << endl;


		//waitKey(intdelay=0)当delay≤ 0时会永远等待；当delay>0时会等待delay毫秒  
		//当时间结束前没有按键按下时，返回值为-1；否则返回按键  
		//int c = waitKey(delay);
		int c = waitKey(1);
		//按下ESC或者到达指定的结束帧后退出读取视频  
		if ((char)c == 27 || currentFrame > frameToStop)
		{
			stop = true;
		}
		//按下按键后会停留在当前帧，等待下一次按键  


		if (currentFrame % 7 == 0)
			imwrite(str.str(), frame);
		currentFrame = currentFrame + 1;

	}
	//关闭视频文件  
	capture.release();

	return 0;
}