Conventions of film

Film opening 
The ritual

Production companies introduced normally two one major and a smaller/independent one.

Actors names

Can include flash backs

Narration

Opening scene before the title comes up

Main characters introduced

Reveals what genre/sub-genre the film is to the audience through sound, typography and lighting

Theatrical trailer
22 jump street

Includes date of when the film is coming out

Extended narrative of the film explained

Key characters introduced

Normally 2 minutes or longer

Teaser Trailer
The hunger games

Between 30-60 seconds in length

Introduces main characters but does not give away the whole narrative.

Normally does not have a date that the film will come out on.

Can contain scenes that are not in the actual film if the director decides to cut that scene.

Normally only made for large budget films

Comes out a long time before the actual film comes out up to a year and a half before the film