每次我捕获视频并将其写入文件时如何给出不同的文件名？

Question

我是opencv的新手。我正在研究项目的一部分。

在下面的代码中，我使用了 VideoWriter 类来存储名称为 MyVideo.avi 的视频，正如我在下面的代码中指定的那样。 但每次我捕获视频时，它都会以相同的名称存储，但它会被覆盖。 所以我想用计算机的日期和时间命名。 请帮我修改

#include "opencv2/highgui/highgui.hpp"
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char* argv[])
{
VideoCapture cap(0); // open the video camera no. 0

if (!cap.isOpened())  // if not success, exit program
{
    cout << "ERROR: Cannot open the video file" << endl;
    return -1;
}

namedWindow("MyVideo",CV_WINDOW_AUTOSIZE); //create a window called "MyVideo"

 double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH); //get the width of frames of the video
double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT); //get the height of frames of the video

cout << "Frame Size = " << dWidth << "x" << dHeight << endl;

Size frameSize(static_cast<int>(dWidth), static_cast<int>(dHeight));

 VideoWriter oVideoWriter ("D:/MyVideo.avi", CV_FOURCC('P','I','M','1'), 20, frameSize, true); //initialize the VideoWriter object 

 if ( !oVideoWriter.isOpened() ) //if not initialize the VideoWriter successfully, exit the program
{
    cout << "ERROR: Failed to write the video" << endl;
    return -1;
}

while (1)
{

    Mat frame;

    bool bSuccess = cap.read(frame); // read a new frame from video

    if (!bSuccess) //if not success, break loop
   {
         cout << "ERROR: Cannot read a frame from video file" << endl;
         break;
    }

     oVideoWriter.write(frame); //writer the frame into the file

    imshow("MyVideo", frame); //show the frame in "MyVideo" window

    if (waitKey(10) == 27) //wait for 'esc' key press for 30ms. If 'esc' key is pressed, break loop
   {
        cout << "esc key is pressed by user" << endl;
        break; 
   }
}

return 0;

}

Answer 1

文件名在源代码中是硬编码的。

初始化oVideoWriter对象时，请改用此代码：

const QString FILENAME = QDateTime::currentDateTime().toString("yyyy-MM-dd_HH.mm.ss") + ".avi";
VideoWriter oVideoWriter(FILENAME, CV_FOURCC('P','I','M','1'), 20, frameSize, true);

这会将文件名设置为当前日期和时间。日期/时间格式Read the docs。

Answer 2

在运行时期间有很多方法可以创建文件名：

按字符串

创建

std::string filename = "image";
filename += "_001";
filename += ".img";

ostringstream创建：

std::ostringstream name_stream;
name_stream << "image" << 2 << ".img";
std::string filename = name_stream.str();

snprintf创建：

char buffer[128];
int chars_printed = snprintf(buffer, sizeof(buffer),
                             "image_%03d.img",
                              3);
std::string filename(buffer);

创建文件名的方法可能更多，但这些示例应该足够了。选择一个适合您需求的产品。