A trailer is a short video that uses clips and footage from an upcoming film to generate publicity and interest. Trailers typically contain dramatic or engaging clips and aim to persuade viewers to see the film without revealing too much of the plot. They are most commonly shown in cinemas before movies, as cinema audiences are highly focused and fall within the target demographic. While trailers can also be shown on television and online, these platforms are less effective at capturing viewers' attention due to distractions and the ability to skip advertisements.