A code is an aspect of a text from which the audience can derive meaning. We can do this through decoding or deconstructing the text; literally breaking it to pieces.
Roland Barthes was a French theorist who studied a variety of fields. Perhaps his most famous contribution to Media Studies was through his study of semiology. The following five codes can be very useful in the process of textual analysis. While you will be making far more use of some than others (action codes and enigma codes for example), learning to apply all five will prepare you for anything that may come up in the exam.
Hermeneutic/ enigma code - An enigma code is a mystery within a text that is not immediately answered. Examples could include "The man lies slumped with an ornate silver knife in his back. Who did it? Why did they do it? And why did they use such a weapon?" As an audience, we assume that this mystery is going to be solved at some point. If it isn't, the audience potentially will be frustrated. On the flip side, if the mystery is revealed too quickly (or if the audience is able to work it out too quickly!), then they could be let down. Writing a successful mystery is a difficult business!
Proairetic/ action code - Parts of a narrative which are related to things happening. For example "Gus glared at Gary, and started to crack his knuckles threateningly". At this point, the audience would probably guess that Gary is going to get punched! This code, along with enigma codes can create considerable suspense. Think about how many times James Bond has disarmed a ticking time-bomb with only one second on the clock! As an audience, we have decoded the action code of the time-bomb, and we assume that Bond is going to die, even though deep inside we know he definitely will survive!
Semantic code - Something within a text that means something, often multiple meanings. There can be many meanings within a single text.
Symbolic code - A part of a text that 'stands in' for, or means something else. For example the gold dress Nicole Kidman wears in the Chanel No.5 advert symbolizes wealth, luxury, glamour and even power. The deeper meaning of a text.
Referential code - Where a part of a text refers to something outside of the text. This assumes the audience has knowledge of whatever it is that the text is refering to. This is closely related to intertextuality, and often it can be the basis for humour. For example, The Big Bang Theory makes frequent reference to other texts, including Star Trek, Star Wars, and other aspects of 'nerd culture'. As an audience, you are more likely to get the joke if you have knowledge of these texts. Likewise, Neil Gaiman's Sandman comics take place in a world where seemingly all myths, legends, gods and comic book heroes exist. It requires a lot of background knowledge to fully comprehend every reference, but the audience can get by if they read it as a creepy story with many enigmas and symbolic codes.