Lip-sync (short for lip synchronization) is a technical term for matching lip movements with voice. The term can refer to: a technique often used for performances in the production of film, video and television shows; the science of synchronization of visual and audio signals during post-production and transmission; the common practice of people including singers performing with recorded audio as a source of entertainment and; matching lip movements of animated characters (including computer facial animation). In the case of live concert performances, lip-synching is generally considered controversial although in many instances it is required from a production standpoint to ensure quality for broadcast or a performer may be harmonizing with their own vocals.


In film production lip-synching is often part of the post-production phase. Most film today contains scenes where the dialogue has been re-recorded afterwards, lip-synching is the technique used when animated characters speak, and lip-synching is essential when films are dubbed into other languages.


Automated dialogue replacement, also known as "ADR" or "looping," is a film sound technique involving the re-recording of dialogue after photography. Sometimes actors lip-synch during filming and sound is added later to reduce costs.


Another manifestation of lip-sync is the art of making a character appear to speak in a prerecorded track of dialogue. The lip-sync technique to make an animated character appear to speak involves figuring out the timings of the speech (breakdown) as well as the actual animating of the lips/mouth to match the dialogue track. The earliest examples of lip-sync in animation were attempted by Max Fleischer in his 1926 short My Old Kentucky Home. The technique continues to this day, with animated films and television shows such as Shrek, Lilo & Stitch, and The Simpsons using lip-synching to make their artificial characters talk. Lip-synching is also used in comedies such as This Hour Has 22 Minutes and political satire, changing totally or just partially the original wording. It has been used in conjunction with translation of films from one language to another, for example, Spirited Away. Lip-synching can be a very difficult issue in translating foreign works to a domestic release, as a simple translation of the lines often leaves overrun or underrun of high dialog to mouth movements.


Early video games did not feature prominent use of voice, mainly being text-based. At most, games featured some generic jaw or mouth movement to convey a communication process in addition to text. However, as games become more advanced, lip sync and voice acting has become a major focus of many games.

Role-playing games

Lip sync is a minor focus in role-playing games. Because of the sheer amount of information conveyed through the game, the majority of communication is done through the use of scrolling text. Most RPGs rely solely on text, while some games display inanimate portraits to provide a better sense of who is speaking. Some games make use of some voice acting, such as Grandia II, but due to simple character models, there is no mouth movement to simulate speech. RPGs are still largely based on text, with the rare use of lip sync and voice files being reserved for full motion video cutscenes. Some newer RPGs, however, use full voice overs. These games are typically for computers or next gen systems and include such games as Star Wars: Knights of the Old Republic and The Elder Scrolls: Oblivion. In these full voice over games, lip sync is crucial.

Strategy games

Unlike RPGs, strategy games make extensive use of sound files to create an immersive battle environment. Most games simply played a recorded audio track on cue with some games providing inanimate portraits to accompany the respective voice. StarCraft used full motion video character portraits with several generic speaking animations that did not synchronize with the lines spoken in the game. The game did, however, make extensive use of recorded speech to convey the game's plot, with the speaking animations providing a good idea of the flow of the conversation. Warcraft III used fully rendered 3D models to animate speech with generic mouth movements, both as character portraits as well as the in-game units. Like the FMV portraits, the 3D models did not synchronize with actual spoken text, while in-game models tended to simulate speech by moving their heads and arms rather than using actual lip synchronization. Similarly, the game Codename Panzers uses camera angles and hand movements to simulate speech, as the characters have no actual mouth movement.

First-person shooters

FPS is a genre that generally places much more emphasis on graphical display, mainly due to the camera almost always being very close to character models. Due to increasingly detailed character models requiring animation, FPS developers assign many resources to create realistic lip synchronization with the many lines of speech used in most FPS games. Early 3D models used basic up-and-down jaw movements to simulate speech. As technology progressed, mouth movements began to closely resemble real human speech movements. To date, the most accurate lip synching in any video game was displayed in a video featuring the new lip synching technology used in the co-op FPS Team Fortress 2. Gamers who create their own videos using character models with no lip movements, such as the helmeted Master Chief from Halo, improvise lip movements by moving the characters' arms, bodies and making a bobbing movement with the head.

The term voice-over refers to a production technique where a non-diegetic voice is broadcast live or pre-recorded in radio, television, film, theatre and/or presentation. The voice-over may be spoken by someone who also appears on-screen in other segments or it may be performed by a specialist voice actor. Voice-over is also commonly referred to as "off camera" commentary.
The term voice-over can also refer to the actual voice actor who performed the recording. The terms voice actor, narrator, voice artist, and announcer are all similarly used.

As a creative device

In film, the film-maker places the sound of a human voice (or voices) over images shown on the screen that may or may not be related to the images being shown. Consequently, voice-overs are sometimes used to create ironic counterpoint. Also, sometimes they can be random voices not directly connected to the people seen on the screen. In works of fiction, the voice-over is often by a character reflecting back on his or her past, or by a person external to the story who usually has a more complete knowledge of the events in the film than the other characters.
Voice-overs are often used to create the effect of storytelling by a character/omniscient narrator. For example, in The Usual Suspects, the character of Verbal Kint has voice-over segments as he is recounting details of a crime. Other examples of storytelling voice overs can be heard in Gattaca, Blade Runner, The Shawshank Redemption, Big Fish, Moulin Rouge! and Goodfellas.
Sometimes, voice-over can be used to aid continuity in edited versions of films, in order for the audience to gain a better understanding of what has gone on between scenes. This was done when the 1948 Joan of Arc, starring Ingrid Bergman, turned out to be far from the box-office and critical hit that was expected, and was edited down from 145 minutes to 100 minutes for its second run in theatres. The edited version, which circulated for years, used narration to conceal the fact that large chunks of the film had been cut. In the full-length version, restored in 1998 and released on DVD in 2004, the voice-over narration is heard only at the beginning of the film.
The genre of film noir is especially associated with the voice-over technique.
In radio, voice-overs are an integral part of the success of the radio programme. Although the announcer holds the prestige and claims all the glory, it is the voice-over artist that is the real drive behind the show. For example, David M. Green's Summer Pow-Wow [1] and his voice-over artist, Tim Wray.

As an educational or descriptive device

The voice-over has many applications in non-fiction as well. Television news is often presented as a series of video clips of newsworthy events, with voice-over by the reporters describing the significance of the scenes being presented; these are interspersed with straight video of the news anchors describing stories for which video is not shown.
Television networks such as The History Channel and the Discovery Channel make extensive use of voice-overs.
Live sports broadcasts are usually shown as extensive voice-overs by expert announcers over video of the sporting event.
Game shows formerly made extensive use of voice-overs to introduce contestants and describe available or awarded prizes, but this technique has diminished as shows have moved toward predominantly cash prizes.
Voice-over commentary by a leading critic, historian, or by the production personnel themselves is often a prominent feature of the release of feature films or documentaries on DVDs.

As a commercial device

The commercial use of voice-over in advertising has been popular since the beginning of radio broadcasting.
In the early years, before effective sound recording and mixing, announcements were produced "live" and at-once in a studio with the entire cast, crew and, usually, orchestra. A corporate sponsor hired a producer, who hired writers and voice actors to perform comedy or drama.
The industry expanded very rapidly with the advent of television in the 1950s and the age of highly produced serial radio shows ended. The ability to record high-quality sound on magnetic tape also created opportunities, as has the proliferation of home computers capable of recording, often using inexpensive (even free) software and a microphone of reasonable quality.

As a translation device

In some countries, a voice-over provided by a single artist is commonly used on television as a localization technique, as an alternative to full dubbing.

In filmmaking, dubbing or looping is the process of recording or replacing voices for a motion picture. The term most commonly refers to voices recorded that do not belong to the original actors and speak in a different language from the one in which the actor is speaking. "Dubbing" also describes the process of an actor re-recording lines they spoke during filming that must be replaced to improve audio quality or reflect dialog changes. This process is called automated dialogue replacement, or ADR for short. Music is also dubbed onto a film after editing is completed.
Foreign-language films, videos and sometimes video games are often dubbed into the local language of their target markets to increase their popularity with the local audience by making them more accessible. Dubbing is common both in theatrically released film and in television series, including Hollywood series and serialized Japanese anime that have received foreign distribution.
Dubbing is often used to localize a foreign movie. The new voice track will usually be spoken by a voice artist. In many countries, most actors who regularly perform this duty are generally little-known, outside of popular circles such as anime fandom, for example, or when their voice has become synonymous with the role or the actor or actress whose voice they usually dub. In the United States, many of these actors also employ pseudonyms or go uncredited due to Screen Actors Guild regulations or simple desire to dissociate themselves from the role. However, famous local actors can also be hired to perform the dubbing, particularly for comedies and animated movies, as their names are supposed to attract moviegoers, and the entire Hollywood cast is dubbed by a local cast of similar notoriety.
Dub localization, also often simply referred to as localization, of which it is a form, is the practice of altering the dubbed translation of a foreign language film or television series to further adapt it for a "local" audience.
Dub localization is a hot button issue amongst aficionados of foreign film and television, particularly anime fans as dubs are still a popular form of translation of animated series. While some localization is virtually inevitable in translation, the controversy surrounding how much localization is "too much" is often much-discussed in such communities, especially when the final dub product is significantly different from the original. Some frown on any extensive localization, while others expect it and, to a degree, appreciate it.
Some dub localizations are considered so extreme as to have produced a different show or film entirely.
In Romania, virtually all programmes intended for children are dubbed in Romanian, including cartoons on Jetix, Cartoon Network, Minimax as well as those shown on generalist television networks, children-focused series like Power Rangers, The New Addams Family, The Planet's Funniest Animals or movies screened on children television. Animation movies are shown in theatres with Romanian dubbing, but usually those cinemas with more screening rooms also provide the original subtitled version; that was the case of such movies like Babe, Atlantis: The Lost Empire, Finding Nemo, Cars, Shrek the Third, Ratatouille, Kung Fu Panda or Wall-e. Other foreign TV shows and movies are shown in the original language with Romanian subtitles. Usually subtitles are preferred in the Romanian market, except for children-intended programme: according to "Special Eurobarometer 243" of the European Commission (research carried out in November and December 2005), 62% of Romanians prefer to watch foreign films and programmes with subtitles, rather than dubbed; nonetheless 22% prefer dubbing, while other 16% declined to answer.[2] This is led by the missconception that watching movies in their original version is very efficient in learning foreign languages. However, only 7 percent of the respondents in that same survey claimed they learned a foreign language by doing so (EU average: 10 percent), compared to 69 percent that learned a foreign language during language lessons at school (EU average: 69 percent). Moreover, according to the Eurobarometer, virtually no Romanian found this method – watching movies in their original version – as the most efficient way of learning foreign languages, compared to 53 percent that chose language lessons at school.

Quality film dubbing requires that the dialogue is first translated in such a way that the words used can match the lip movements of the actor. This is often impossible to achieve if the translation is to stay true to the original dialogue. Elaborate lip-synch of dubbing is also a very lengthy and expensive process.
In English-speaking countries, many foreign TV series, especially Japanese anime, are dubbed to be put on television. However, cinematic releases of films tend to come with subtitles instead. The same is true of countries in which a language is spoken that is not spoken widely enough to make the expensive dubbing commercially viable (in other words, there is not enough market for it).
However, most non-English-speaking countries with a large enough population dub all foreign films into their national language before releasing them to cinemas. In such countries, people are accustomed to dubbed films so much that somewhat less than optimal matches between the lip movements and the speech are not generally noticed. At the same time, they are unaccustomed to subtitles, so they tend to find them distracting because they lack the skills to follow the on-screen action and the subtitles at the same time.