Reading video sequences

To process a video sequence, we should be able to read each frame. OpenCV has developed an easy-to-use framework that can work with video files and camera input.

The following code is a videoCamera example that works with a video captured from a video camera. This example is a modification of an example in Chapter 1, Getting Started, and we will use it as the basic structure for other examples in this chapter:

#include "opencv2/opencv.hpp"

using namespace std;
using namespace cv;

int videoCamera()
{
    //1-Open the video camera
    VideoCapture capture(0);

    //Check if video camera is opened
    if(!capture.isOpened()) return 1;

    bool finish = false;
    Mat frame;
    Mat prev_frame;
    namedWindow("Video Camera");

    if(!capture.read(prev_frame)) return 1;

    //Convert to gray image
    cvtColor(prev_frame,prev_frame,COLOR_BGR2GRAY);

    while(!finish)
    {
        //2-Read each frame, if possible
        if(!capture.read(frame)) return 1;

     ...