How to record, capture the desktop?

Question

linux

Good afternoon
Do not tell me how you can capture video from the desktop on the pluses?
For example, I have an application in which there is a window where the desktop is shown.
Maybe there are some functions in OpenCV?
This is certainly good, but I climbed into the documentation and did not understand anything - where to start ?.
The devil's leg will break there. Maybe someone worked with this library and has some sketches?
I just need to read the information from the screen.
Maybe someone has some kind of snares for example, use, etc.?

Answer 1

All this can be done by ffmpeg and gstreamer. Why do you need a bike?

Answer 2

https://trac.ffmpeg.org/wiki/Capture/Desktop

Answer 3

I understood this, but I need to implement it in C++ code.