Trailer terminology

Plot summary
The majority of film trailers have whats known as a three act structure similar to a feature length film, a beggining, this lays out the story, the middle that drives the story and the end which usually has a dramatic climax. These are commonly known as act 1,2 and , act 3 normally has a strong piece of signature music to end it. Act 3 also has a visual montage of powerful emotional moments during the film with a build up.

Voice over
Voice over or narrative is used to briefly set up the premise of the movie and provide explanation when necessary, useful to enhance the audiance understanding.

Music
Music helps to set the tone and the mood of the scene and to create an atmosphere.

cast,crew
cast is a run list of people who will appear in the trailer/movie. This list usually appears at the end of the film.

Technical ElementsSound Mix:  many different movie trailers are presented in Dolby Digital or any other multi channel sound mix. Scenes will include sound affects and also music that will have been enhanced by stereophonic sound and this is the focus point of modern day film trailers.Video Resolution: Trailers today which are feature films are generally presented in the same format as the actual feature, being in general terms 35mm film or digital format.  High bandwidth internet connection will allow trailers to be distributed at any type of resolution up to 1080p.