compositing

thumb|thumbtime=18|Exchanging the background of a video clip with a Compositing tool thumb|A composite image of a basketball shot, with six basketballs added to the initial image to depict the arc of the shot.

Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most compositing is achieved through digital image manipulation. Pre-digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use.