Qlabel in video not showing - Raspberry pi 4 Opencv 4.1.0

[bknhatice]

I installed Opencv 4.1.0 and Qt Creator on Rpi 4. I created a gui with a button and a label. When the button is clicked, I want the video to play in the label. The codes I use for this are:
VideoCapture cap(“/home/users/video.mp4”);
  if(!cap.isOpened()){
     cout << "Error opening video stream or file" << endl;
     return -1;
  }

while(1)
{
	Mat frame;
	cap >> frame;
	if (frame.empty())

break;

	Qimage img = Qimage((uchar*) frame.data, frame.cols, frame.rows, frame.step, Qimage::Format_RGB888);
	ui→label→setPixmap(QPixmap::fromImage(img));
	char c = (char) waitKey(25);
	if(c==27)
		break;
}
cap.release();
destroyAllWindows();

No video is shown in Label. But imshow (“Frame”, frame); When I add the command line, the video is displayed in the label.
How can I show the video in qlabel ?

[SGaist]

Hi,

You are blocking the event loop with your tight loop as well as your wait key.

Use a Timer that will read your file at regular interval since you anyway wait for 25ms.

[bknhatice]

ui->label->repaint()