Diegetic and Non-Diegetic Sound

Diegetic sound is sound that has a source in the scene and can be heard by the characters within. Its source can be on screen or off screen, and is usually only seen in narrative music videos. Examples of diegetic sound include speech and noises that occur within the world.

Non-Diegetic sound is sound that can only be heard by the audience and not the characters in the scene. Examples of non-diegetic sound are a narration, or music/soundtracks.

Part of Me by Katy Perry contains both diegetic and non-diegetic sound. The start of the music video is a narrative and contains diegetic sound, but the majority of the video is non-diegetic sound as it is a music video.