I would like to duplicate the images of a video via a vector, There are the right number of frames in vector but when copying, they are empty when writing the file, so the file only has the first copy of the frames but not the rest.
I think the problem comes from this loop but I do not know why it does not work :
for (cv::Mat &trame_vid : video_vect) {
video_vect.emplace_back(trame_vid.clone());
}
Clone makes a copy and it is sent to the vector via emplace_back(), if I understand correctly ?
the entire code :
std::string filename = "chaplin.mp4";
cv::VideoCapture capture(filename);
if (!capture.isOpened())
throw "Error when reading chaplin.mp4";
double fps = capture.get(cv::CAP_PROP_FPS);
cv::Mat frame;
std::vector<cv::Mat> video_vect;
video_vect.reserve(capture.get(cv::CAP_PROP_FRAME_COUNT) * 2);
while (1) {
// Capture frame-by-frame
capture >> frame;
// If the frame is empty, break immediately
if (frame.empty())
break;
// Copy current image to vector
video_vect.emplace_back(frame.clone());
imshow("Frame", frame);
// ESC to stop
char c = (char)cv::waitKey(20);
if (c == 27)
break;
}
int codec = cv::VideoWriter::fourcc('X', '2', '6', '4');
cv::VideoWriter video("out.avi", codec, (int)fps,
cv::Size(frame_width, frame_height), true);
std::cout << video_vect.size() << std::endl;
//Copy Mat
for (cv::Mat &trame_vid : video_vect) {
video_vect.emplace_back(trame_vid.clone());
}
std::cout << video_vect.size() << std::endl;
for (cv::Mat &trame_vid : video_vect) {
video.write(trame_vid);
}
// Liberation des ressources
capture.release();
video.release();
video_vect.clear();
video_vect.shrink_to_fit();
// Closes all the frames
cv::destroyAllWindows();