OpenCV в Visual Studio с использованием C ++. Как вырезать выбранное время из видеофайла?

У меня есть 5 минут MP4 видео файл. Я хочу сократить от 2 до 3 минут.

Например. Video1.mp4 — это видео продолжительностью 5 минут, на выходе должен быть другой файл с именем Video2.mp4, содержащий от 2 минут до 3 минут из Video1.mp4.

Что мне нужно редактировать из кода ниже? Пожалуйста помоги?

#include "stdafx.h"     //By default

#include < string.h>

#include < stdio.h>

#include < stdlib.h>

#include "cv.h"
#include < highgui.h>

#include "cxcore.h"
#include <iostream>     //To use cout and cin

using namespace cv;     //To use VideoCapture

//Public file path

string fullPath;

VideoCapture capture(0);void ExplicitWM()

{

//Explicit Watermark

//Input Message
char txt[100] = {'\0'};
cout << "Enter message to encode: " << endl;
cout<<"-----------------------"<< endl;
cin >> txt;double dWidth = capture.get(CV_CAP_PROP_FRAME_WIDTH); //get the width of frames of the video
double dHeight = capture.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));

//Save Video to desktop
string userProfile = getenv("userprofile");
string path = userProfile + "\\Desktop\\";
string saveVid;
getline (cin, saveVid);
string fullPath = path + saveVid;

//CV_FOURCC('P','I','M','1') is a MPEG-1 codec
VideoWriter oVideoWriter (fullPath + "SavedVid.avi", CV_FOURCC('P', 'I', 'M', '1'), 30, 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;
}

while ( capture.isOpened() )
{
Mat frame;

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

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

Mat imgW = frame;

// cvScalar(255,255,255) = rgb
// cvPoint(40,40) = x-y cord
// 0.8 = font size
putText(imgW, txt, cvPoint(400,400), CV_FONT_HERSHEY_COMPLEX, 0.8, cvScalar(255,255,255), 1, CV_AA);imshow("Watermarked Video", imgW); //show the frame of which watermark added

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

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

int main(int argc, char* argv[] )

{

cout<< endl;

cout << "Place video in Desktop and enter file name (e.g. vid.avi):" << endl;

cout<<"--------------------------------------"<< endl;

//Get user desktop file path

string userProfile = getenv("userprofile"); //GetEnvironmentVariable() is to get current userprofile (e.g."C:\Users\L30807")

string path = userProfile + "\\Desktop\\";

string vid;

getline (cin, vid);     //Prompt to input file name
fullPath = path + vid;
capture.open(fullPath); //Read video
cout<< endl;

if ( capture.isOpened() )
{
char choice;
cout<< "Choose option (a or b): "<< endl;
cout<<"-----------------------"<< endl;
cout<< "a.Encode Video "<<endl;
cout<< "b.Decode Video "<<endl;
cout<<"-----------------------"<< endl;
cin >> choice;
cout<< endl;

if (choice== 'a')//Encode Video
{
int choiceEn;
cout<< "Choose option (1 or 2): "<< endl;
cout<<"-----------------------"<< endl;
cout<< "1.Explicit Watermarking " <<endl;
cout<< "2.Implicit Watermarking(DCT) "<<endl;
cout<<"-----------------------"<< endl;
cin >> choiceEn;
cout<< endl;

switch ( choiceEn )
{
case 1:
ExplicitWM();
break;

default:
cout<<"Error: Wrong input. Exiting..." << endl;
return 0;
}
}

else if (choice== 'b')
{

}
}