Trailer Music can be grouped into Teasers (15-30 sec), Trailers (1-1:30), and Theatrical Trailers (1:30-2:30). The term “trailer” comes from their having originally been shown at the end of a feature film screening. That practice did not last long, because patrons tended to leave the theater after the film ended, but the name still stuck. Trailers are now shown before the film begins. And has somewhat become a music genre. You can also find great teasers in our 30-60 sec categories.