Andrew Goodwin identified a number of key features which distinguish the music video as a form, before you understand his theory you need to understand some key terminology.
Illustrate: Images used to represent the meanings of the lyrics and genre (this is the most common feature of a music video) this is very often literal.
Disjuncture: When the meaning of the song is completely ignored
Amplify: Meanings and effects are manipulated and constantly shown throughout the video and shown to the audience (basically repetition).
