Reverse video playback in OpenCV

Question

Is it possible to play videos backwards in OpenCV? Either by an API call or by buffering video frames and reversing the order into a new video file.

Thanks

Answer 1

Yes, it's possible. See code with comments:

//create videocapture
VideoCapture cap("video.avi");

//seek to the end of file
cap.set(CV_CAP_PROP_POS_AVI_RATIO, 1);

//count frames
int number_of_frames = cap.get(CV_CAP_PROP_POS_FRAMES);

//create Mat frame and window to display
Mat frame;
namedWindow("window");

//main loop
while (number_of_frames > 0)
{
    //decrease frames and move to needed frame in file
    number_of_frames--;
    cap.set(CV_CAP_PROP_POS_FRAMES, number_of_frames);

    //grab frame and display it
    cap >> frame;
    imshow("window", frame);

    //wait for displaying
    if (waitKey(30) >= 0)
    {
        break;
    }
}

Also read this article.