The document discusses various codes and conventions used in film opening sequences. It identifies elements like studio logos, titles, themes, character introductions, sound, narration, enigma, credits, flashbacks, establishing shots, action scenes, and animation that are commonly used to set the tone and genre of a film and grab audience attention. Sound specifically is discussed as being used to display emotion through dialogue, ambient noise, sound effects, and soundtrack. The purpose of these various elements in opening sequences is to effectively introduce audiences to the world of the film.