Movie trailers, or previews, are film advertisements for films that will be exhibited in the future at a cinema, on whose screen they are shown. The term "trailer" comes from their having originally been shown at the end of a film programme. That practice did not last long, because patrons tended to leave the theater after the films ended, but the name has stuck. Trailers are now shown before the film (or the A movie in a double feature programme) begins.
Trailers normally consist of a series of selected shots from the film being advertised. Since the purpose of the trailer is to attract an audience to the film, these excerpts are usually drawn from the most exciting, funny, or otherwise noteworthy parts of the film but in abbreviated form and without producing spoilers. For this purpose the scenes are not necessarily in the order in which they appear in the film. A trailer has to achieve that in less than two and a half minutes, the maximum length allowed by theaters. Each studio or distributor is allowed to exceed this time limit once a year, if they feel it is necessary for a particular film.
Some trailers use "special shoot" footage, which is material that has been created specifically for advertising purposes and does not appear in the actual film. The most notable film to use this technique was Terminator 2: Judgment Day, whose trailer featured elaborate special effects scenes that were never intended to be in the film itself. One of the most famous "special shoot" trailers is that used for the 1960s thriller Psycho which featured director Alfred Hitchcock giving viewers a guided tour of the Bates Motel, eventually arriving at the infamous shower. At this point, the soft-spoken Hitchcock suddenly throws the shower curtain back to reveal Vera Miles with a blood-curdling scream.
The people who create trailers often begin their work while the movie is still being shot. Since the edited movie does not exist at this point, the trailer editors work from rushes or dailies. The trailer may be created at the agency while the movie itself is being cut together at the studio. Thus, the trailer may contain footage that is not in the final movie, or the trailer editor and the movie editor may use different takes of a particular shot.
Some trailers that incorporate material not in the movie are particularly coveted by collectors, especially trailers for classic films. For example, in a trailer for Casablanca the character Rick Blaine says "OK, you asked for it!" before shooting Major Strasser, an event that does not occur in the final film.
Parts of a trailer
Trailers tell the story of a movie in a highly condensed, maximally appealing fashion. In the decades since movie marketing has become a large industry, trailers have become highly polished pieces of advertising, able to present even poor movies in an attractive light. Some of the elements common to many trailers are listed below.
A green band is an all-green graphic at the beginning of the trailer, usually reading "The following PREVIEW has been approved for ALL AUDIENCES by the Motion Picture Association of America," and sometimes including the movie's MPAA rating. This signifies that the trailer adheres to the standards for motion picture advertising outlined by the MPAA, which includes limitations on foul language and violent, sexual, or otherwise objectionable imagery. Trailers that do not adhere to these guidelines may be issued a red band, (which used to be blood red) which reads "The following PREVIEW has been approved for RESTRICTED AUDIENCES ONLY by the Motion Picture Association of America," and may only be shown before an R-rated, NC-17-rated, or unrated movie. The MPAA also mandates that trailers not exceed two minutes and thirty seconds in length, and each major studio is given one exception to this rule per year.
Usually studio logos are featured near the beginning of the trailer. Until the late 1970s, those were put only at the end of the trailer. Often there will be logos for both the production company and distributor of the film.
Most trailers have a three-act structure similar to a feature-length film. They start with a beginning (act 1) that lays out the premise of the story. The middle (act 2) drives the story further and usually ends with a dramatic climax. Act 3 usually features a strong piece of "signature music" (either a recognizable song or a powerful, sweeping orchestral piece). This last act often consists of a visual montage of powerful and emotional moments of the film and may also contain a cast run if there are noteworthy stars that could help sell the movie.
Voice-over narration is used to briefly set up the premise of the movie and provide explanation when necessary. Since the trailer is a highly condensed format, voice-over is a useful tool to enhance the audience's understanding of the plot. Some of the best-known voice-over artists are Don LaFontaine, Andy Geller, Hal Douglas, Mark Elliott, George DelHoyo, Peter Cullen and Ashton Smith.
Music helps set the tone and mood of the trailer. Usually the music used in the trailer is not from the film itself (the film score may not have been composed yet). The music used in the trailer may be:
Music from the score of other movies
Popular or well-known music, often chosen for its tone, appropriateness of a lyric, or recognizability
"Library" music previously composed specifically to be used in advertising by an independent composer
Specially composed music. One of the most famous Hollywood trailer music composers is John Beal, who began scoring trailers in the 1970's and, in the course of a thirty year career, created original music for over 2,000 movie trailer projects, including 40 of the top-grossing films of all time, such as Star Wars, Forrest Gump, Titanic, Aladdin, Last Samurai and The Matrix.
Songs, which may include knock-offs of recognizable (but expensive to license) songs
A cast run is a list of the stars that appear in the movie. If the director or producer is well-known or has made other popular movies, they often warrant a mention as well.
Most trailers conclude with a billing block, which is a list of the principal cast and crew. It is the same list that appears on posters and print publicity materials, and is the same list that usually appears on-screen at the beginning of the movie.
Sound Mix Many Movie Trailers are presented in Dolby Digital or any other Multichannel sound mix . Is very probable to hear dramatic explosions and music in multichannel sound during a movie trailer.
Video resolution Movie trailers are presented in the same resolution as the feature film. In HDTV Channels (such as Universal HD) movie trailers are presented in HDTV and Dolby Digital 5.1 Sound.