This is a Python script that uses the pyautogui and OpenCV libraries to record the screen of a selected monitor. The script prompts the user to select a screen to record, creates a VideoWriter object to save the recording as an AVI file, and uses pyautogui to take screenshots of the selected screen and OpenCV to write the screenshots to the video file.

The script also uses the tkinter library to create a simple GUI with "Start Recording" and "Stop Recording" buttons. The "Start Recording" button starts a new thread that runs the start_recording() function, and the "Stop Recording" button sets a global variable called "recording" to False, which stops the while loop in the start_recording() function and releases the VideoWriter object to save the video file.