Narratives are subtitles that represent relevant textual information appearing onscreen, as opposed to dialogue. There are two different types of narrative titles
Principal photography narratives (PP)
Principal photography narratives represent text that appears within the filmed reality. For example: road signs, newspaper headlines, an address on an envelope, and information displayed on a computer or TV screen
Burn-in narratives (BI)
Burn-in narratives represent text added in post-production and which does not exist in the reality of the movie. These narratives are often used to identify people, locations or time ("Quentin Tarantino, Director," "Tokyo, 1987" "Two months later," etc.). They may also be used to translate non-English audio.