A trailer is a short film that gives audiences an idea of what to expect in a movie. It also entices them to see the finished product. Movies are expensive to produce and to market, so trailers play an important role in a studio’s promotional strategy. They are a form of pre-release film marketing that can be aired on television, shown in theaters before the main feature, or released online.

A movie’s trailer is usually about two minutes long. It is not a full-length film, but it is designed to sell audiences on the story and the characters. In addition to describing the film, the trailer may also include cast lists, a brief plot summary, and music. The film studio’s production logo is often displayed at the beginning of the trailer. A montage of scenes from the movie usually follows the cast list and plot summary.

In the 1950s and 1960s, trailers began to resemble miniature films. They included the movie’s setup, confrontation, and climax. At the same time, they began to rely more on star power and special effects. This era gave rise to the modern-day formula that still exists for some film trailers.

Since the advent of high-speed Internet connections, more types of trailers have appeared. YouTube has become the newest sandbox for editors of trailers, allowing them to create Honest Trailers and other fascinating recuts of the most popular movies. Trailers are also now available in 3-D.

Most movie trailers follow a three act structure similar to a full-length film. The first act lays out the basic premise of the film, then the middle drives the story forward. The final act is a dramatic climax with a rousing signature piece of music. A cast run is often included at the end of the trailer if the film stars prominent actors or actresses.

Occasionally, a film will be in the midst of post-production when the trailer is released. This can cause problems, as the VFX will be incomplete. Sometimes the trailer will be edited with a soundtrack of songs that will not appear in the film, so that the audience has something to hold onto while waiting for the movie to arrive in theaters.

Some movie trailers use genre as a selling tool, drawing in audiences with a sense of spectacle and demonstrating that the film will have all the fight scenes and explosions they desire. Others rely on star power to persuade audiences to attend. Still others make the most of creative editing to tell a story that might not have enough room in a two-hour film.

Most modern trailers are presented in Dolby Digital or other multichannel sound mixes. The audio is more important in modern trailers than the visuals, as most viewers will not see the film in 3-D and are unlikely to have access to special effects and music. The sound is also important for establishing the setting and atmosphere in the film.