cv2.VideoCapture is a class for video capturing from video files, image sequences or cameras. We set the frame rate to be 0.5 seconds, which would capture the frame every 0.5 secods. That is, 2 frames per second. The program saves the images as image[num].jpg in an images folder.
For combining images into a video we add path variables to the image folder and set the images in a list. We sort this list in order so that we have the image sequence right. Using a frame-rate, here, 0.5, we can output a video in .avi format.
Using the cv2.VideoCapture class, we can access the webcam. We keep the video displayed constantly, hitting the SPACE key clicks a picture which is saved in the images folder, as opencv_frame_[num].jpg. Hitting the ESC key quits the window.
Having a green screen video and another which would act as a background, we use openCV to mask the green screen. This was challenging as the window quit with an error, but still gave the desired output.