OpenCV C++ Program to blur a Video

The following is the explanation to the C++ code to blur a video in C++ using the tool OpenCV.

Things to know:

(1) The code will only compile in Linux environment.

(2) To run in windows, please use the file: ‘blur_video.o’ and run it in cmd. However if it does not run(problem in system architecture) then compile it in windows by making suitable and obvious changes to the code like: Use <iostream.h> in place of <iostream>.

(3) Compile command: g++ ­w blur_vid.cpp ­o blur_vid `pkg­config ­­libs opencv`

(4) Run command: ./blur_vid

(5) The video Bumpy.mp4 has to be in the same directory as the code.

Before you run the code, please make sure that you have OpenCV installed on your // system.

Code Snippets Explained:

#include "opencv2/highgui/highgui.hpp"
// highgui - an interface to video and image capturing.
#include <opencv2/imgproc/imgproc.hpp> // For dealing with images
#include <iostream>
// The header files for performing input and output.

using namespace cv;
// Namespace where all the C++ OpenCV functionality resides.

using namespace std;
// For input output operations.

int main()
{
    VideoCapture cap("Bumpy.mp4");
    // cap is the object of class video capture that tries to capture Bumpy.mp4
    if ( !cap.isOpened() ) // isOpened() returns true if capturing has been initialized.
    {
        cout << "Cannot open the video file. \n";
        return -1;
    }

    double fps = cap.get(CV_CAP_PROP_FPS); //get the frames per seconds of the video
    // The function get is used to derive a property from the element.
    // Example:
    // CV_CAP_PROP_POS_MSEC : Current Video capture timestamp.
    // CV_CAP_PROP_POS_FRAMES : Index of the next frame.
 
    namedWindow("A_good_name",CV_WINDOW_AUTOSIZE); //create a window called "MyVideo"
    // first argument: name of the window.
    // second argument: flag- types:
    // WINDOW_NORMAL : The user can resize the window.
    // WINDOW_AUTOSIZE : The window size is automatically adjusted to 
    //fit the displayed image() ), and you cannot change the window size manually.
    // WINDOW_OPENGL : The window will be created with OpenGL support.

    while(1)
    {
        Mat frame;
        // Mat object is a basic image container. frame is an object of Mat.
        if (!cap.read(frame)) // if not success, break loop
        // read() decodes and captures the next frame.
        {
            cout<<"\n Cannot read the video file. \n";
            break;
        }
    blur(frame,frame,Size(10,10)); // To blur the image.
    imshow("A_good_name", frame);
    // first argument: name of the window.
    // second argument: image to be shown(Mat object).
    
    if(waitKey(30) == 27) // Wait for 'esc' key press to exit
    {
        break;
    }
}
return 0;
}
// END OF PROGRAM