A trailer is a preview of a feature film soon to be released in to the cinemas and are shown at the beginning of other films. The trailer shows a summary of a plot and usually last up to a few minutes. There are normally several versions of a trailer, showing slightly different aspects of the film it's advertising. Trailers also advertise new television programmes and DVDs on the internet as well as on TV and in cinemas.
Teaser trailer is a much shorter trailer (usually between 30-60 seconds) advertising an upcoming film, television program or video game usually released long before the product is released. Teaser ads are also used in advertising campaigns, so to ‘tease’ the audience about what is yet to be released. For example billboards and adverts on busses will be teaser ads.
