In its most basic sense, a deepfake is a combination of face- and voice-cloning AI technologies that allow for the creation of life-like, computer-generated videos of a real person.
In order to develop a high-quality deepfake of an individual, developers need to accumulate tens of hours of video footage associated with the person whose face/voice is to be cloned, as well as a human imitator who has learned the facial mannerisms and voice of the target.