This chapter is true for Qt5 only, in Qt6 the rules of the game have been changed.
In this chapter I will show how to work with QCamera, QAbstractVideoSurface.
How to detect motion with OpenCV, capture with QCamera frames and store them
in some place on the disk. This chapter is based on the real project SecurityCam
that places on GitHub https://github.com/igormironchik/security-cam
In this chapter I will describe only the most interesting parts of the code of SecurityCam, I won't show you how I save configuration file, how I organized configuration of the application. Only a few words, that for reading/saving configuration file I used cfgfile. This is Open Source library for reading and saving configurations. It places on GitHub https://github.com/igormironchik/cfgfile
SecurityCam is an application that connects to USB camera and tries to detect motions in the frame, as soon as motion is detected camera starts to capture images and store them in the configured folder with yyyy/MM/dd hierarchy. SecurityCam can do clean at the configured time and delete folders with images that stored more than N days.
The window of the application displays stream from the camera and on closing minimizes to tray, so the application works in the background and protects the entrusted territory.