A trailer is a short film that previews a feature-length film. It is usually presented prior to the feature film in a movie theater or is broadcast on television before the main show.

Most modern movie trailers follow a three-act structure similar to a feature film. The first act lays out the premise of the story, the middle acts build on that premise, and the final act ends with a dramatic climax. The trailers often feature a strong piece of “signature music” that lasts the duration of the trailer. The music and editing are synchronized so that every shot in the trailer is built to match the key emotions and ideas being conveyed.

In addition to being a marketing tool, the trailer is also used as a form of art in its own right. Trailer editors are considered to be among the most skilled film artists in the world. They are able to present even poor films in an attractive light.

The first trailers were essentially a clip show of scenes from the feature film, accompanied by text that screamed questions at the audience, like, “Does she escape the lion’s pit?” and “See next week to find out!”

When the movie industry became a multi-billion dollar business, studios began to take their trailer production seriously and create more versions for different markets. They also hired voiceover artists, such as the renowned French actor Alain Delon, to give a narrative foundation to each trailer. The voiceover would set the world each trailer was taking place in and explain the narrative structure and story arc of each film.

By the 1980s, trailers were starting to resemble mini-movies, and many incorporated the film’s plot, setting, conflict, and climax-sometimes revealing too much. This style was very effective and led to a solid formula that still holds up today.

Many of today’s trailers have a high energy, with each shot designed to match the beat of an updated version of an iconic classic rock song. The music helps to heighten feelings of excitement, anticipation, and fear. The 2011 trailer for The Girl with the Dragon Tattoo is a great example of this modern aesthetic.

While many modern trailers are heavily influenced by the soundtrack, sound effects can be just as important. Using ambient sounds of battle can indicate that a war movie is being released, or the use of pulsing drums can suggest a science fiction trailer.

The Internet has changed the way that trailers are created and distributed. YouTube and other websites have become studios’ newest, cost-effective, and most successful marketing tools. They are able to reach an enormous audience of potential viewers for free, release red-band trailers that cannot be shown on television, and develop extensive campaigns that include teasers and countdowns. The online sandbox also allows editors to play with trailers, giving them the Honest treatment and fascinating recuts, such as turning Mary Poppins into a horror movie and The Shining into the feel-good comedy of the year.