Editing

Editing is the putting together of pieces of film into a sequence and the preparation of written, visual, audible and media used to convey information to their target audience. It is also the manipulation of the mis en scene of a sequence or deleting Un-needed parts e.g. cut offs that weren't included in the film or adding in cg effects and transitions.
Definitions of editing:
Continuity is when the audience don't realize when a cut has been made but the cut offs are made to look in line with each other to create a narrative story that appears to be smooth .
Montage is when relevant shots and information have been used to recap a story  in a short way.
Transitions is the way editors transfer one shot to another using a technique such as
fading out or straight cuts.

Trailers often use montage or match on action scenes of information from the film to tease the audience and leave them hanging off all the time. The most common transition in trailers made is usually quick straight shots to build the mood for the film by creating more fast paced intensity to build on to a climax at the end to get people watching.
Trailer opening analysis: The butterfly effect


This first shot fades out into the rest of the opening sequence without a straight cut to make it more harmonious with the smooth running sequence.


Continuity is used in this shot, however more match on action with the writing that appears before the shot change that creates continuity in the sequence.


In this shot match on action of the brain scan we see here into a butterfly which breaks up into a smoother sequence.