Story Telling Unit-Trailer Research, Drama

I watched two trailers that are both drama's to see the conventions used in the trailers. Such as music being slow and not much singing. There is also a lot of dialogue which is not present in action films. They have voice overs, this is either a character or a omnipotent like voice that follows the characters to tell parts of the story. They have very little transition as most of the film is cut straight, although they do cut to black and have titles throughout. These titles do not add to the story they more advertise the makers and actors in the story.