opencv读取多个视频获取当前帧数并阁帧数截图保存

#include 
#include 
#include 

using namespace std;
using namespace cv;
char image_name[30];
int i=1;

int main()
{
	VideoCapture cap;
	//cap.open(0);        //打开摄像头
	cap.open("33.mp4");   //打开视频

	int frameRate    = static_cast(cap.get(CV_CAP_PROP_FPS));          //帧率 x frames/s
	int totalFrames  = static_cast(cap.get(CV_CAP_PROP_FRAME_COUNT));  //总帧数
	int width        = static_cast(cap.get(CV_CAP_PROP_FRAME_WIDTH));  //帧宽度
	int height       = static_cast(cap.get(CV_CAP_PROP_FRAME_HEIGHT)); //帧高度 
	int frameToStart = static_cast(cap.get(CV_CAP_PROP_POS_FRAMES));   //帧开始

	cout << "视频宽度="   << width        << endl;
	cout << "视频高度="   << height       << endl;
	cout << "视频总帧数=" << totalFrames  << endl;
	cout << "帧率="      << frameRate    << endl;
	cout << "从第"       << frameToStart << "帧开始读" << endl;

	Mat img, imgGray;
	int c = 0;
	int framenum=frameToStart;

	while (c !=27)
	{
		cap >> img; 
		framenum++;
		if (img.channels() == 3)                   //三通道红绿蓝,彩色图像
				{
			cvtColor(img, imgGray, CV_RGB2GRAY);   //变成灰色图像
		} else {
			imgGray = img;
		}
		
		cout << "正在读取第" << framenum << "帧" << endl;
		if ( framenum % 2 == 0 ) //此处为帧数间隔，修改这里就可以了
        {
			cout << "正在写第" << framenum << "帧" << endl;
			//sprintf(image_name, "%s%d%s", "f", framenum, ".jpg");
			sprintf(image_name, "%s%d%s", "f", ++i, ".jpg");
			imwrite("face\\" + string(image_name), imgGray);
		}
			waitKey(1000); //每隔三秒显示

		//imag = imread("mv3.jpg",16);
		//result = img.clone();
		//threshold(img, result, 100, 250, THRESH_OTSU);
		//imwrite(i + "hd.jpg",imgGray);
	}
	return 0;
}

 按顺序读取视频

#include 
#include 
#include 

using namespace std;
using namespace cv;
char image_name[30];
int i=1;

int main()
{
	VideoCapture cap;
	//cap.open(0);        //打开摄像头
	char filename[200];
	for(unsigned int k=1;k<200;k++)
	{
		sprintf(filename,"%d.mp4",k);
		cap.open(filename);   //打开视频

		int frameRate    = static_cast(cap.get(CV_CAP_PROP_FPS));          //帧率 x frames/s
		int totalFrames  = static_cast(cap.get(CV_CAP_PROP_FRAME_COUNT));  //总帧数
		int width        = static_cast(cap.get(CV_CAP_PROP_FRAME_WIDTH));  //帧宽度
		int height       = static_cast(cap.get(CV_CAP_PROP_FRAME_HEIGHT)); //帧高度 
		int frameToStart = static_cast(cap.get(CV_CAP_PROP_POS_FRAMES));   //帧开始

		cout << "视频宽度="   << width        << endl;
		cout << "视频高度="   << height       << endl;
		cout << "视频总帧数=" << totalFrames  << endl;
		cout << "帧率="      << frameRate    << endl;
		cout << "从第"       << frameToStart << "帧开始读" << endl;

		Mat img, imgGray;
		int c = 0;
		int framenum=frameToStart;

		//while (c !=27)
		//while (framenum !=60)
		for(framenum;framenum<60;framenum++)
		{
			cap >> img; 
			//framenum++;
			 if (img.channels() == 3)                   //三通道红绿蓝,彩色图像
			 {
			 	cvtColor(img, imgGray, CV_RGB2GRAY);   //变成灰色图像
			 } else {
			 	imgGray = img;
			 }
			
			cout << "正在读取第" << framenum << "帧" << endl;
			if ( framenum % 2 == 0 )                    //此处为帧数间隔，修改这里就可以了
			{
				sprintf(image_name, "%s%d%s", "1", ++i, ".jpg");
				imwrite("face\\" + string(image_name), imgGray);
			}
			waitKey(10);                           //每隔三秒显示
		}
		//namedWindow("face", 0);
		//imshow("face",imgGray);
		//return 0;
	}
}

g++ -o hd hd.cpp  `pkg-config --cflags --libs opencv`