How Does Lip-Sync Dubbing Work?

A video primer on lip-sync dubbing at Power of Babel, using VoiceQ digital rythmo-band technology.

We’ve talked a lot in this blog about whether to dub or subtitle your video content. Sure, many of us foreign-film fans prefer subtitles. But in many countries, virtually all foreign content is dubbed, with varying degrees of success.

So, how does that actually work? How is a lip-sync dub of a movie or TV show produced, and why is it so difficult to do well? Because it’s a multi-stage process with challenges everywhere along the way.

There are four steps to the process:


It’s not enough to translate the as-produced transcript of your film. To sound and look accurate, the dubbed version has to reproduce every audible breath, every grunt, every chuckle and vocal nuance of the original. So the first step is to go through the film very carefully, and make a note of these extra sounds.

Translation and Adaptation

This is where it gets tricky. The new language not only has to capture the meaning and context of the script, it has to match the duration of the original syllable for syllable, and also – as much as possible – follow the mouth movements. So, for example, the translator has to have a mental catalogue of synonyms containing the letters M, P and B – sounds that are made with the lips closed. That’s a mouth movement that’s hard to disguise as something else. In the end, lip-sync adaptation is rarely perfect, but it has to be believable: it has to make the audience forget that it’s watching a dubbed movie.


For actors, this has to be one of the hardest jobs to do well. The actor stands in a recording booth or on a sound stage, and re-creates the performance on screen in another language. She or he has to capture the mood and emotion of the original, plus hit every audio mark: make sure that every vowel is exactly as long as it needs to be, and that lip movements line up with those of the actor on screen. This is where dubbing software – such as our preferred tool, VoiceQ – really does its job. Have a look at our video, and see how rythmo band technology allows the actor to follow a super-precise script and stay in the moment at the same time, delivering a great performance in the fewest number of takes possible.


After the actors leave, the recording engineer still has a lot of work to do:

    • Cleaning up the dialogue, getting rid of extra breaths, popped P’s and overly hissy S’s, and evening out the levels
    • Recreating the ambience of scenes shot outdoors or in other noisy locations
    • Placing the voices appropriately in the stereo or 5.1 environment, so they sound like they’re coming from the right place on screen.

At the end, says Power of Babel Technical Director Dave Boire, “if the viewer doesn’t notice our work, we’ve done our job.”

Et voilà! Now the film is ready to be screened or broadcast in a new language.

If you need your film, TV series or any other video content dubbed, we’d love to talk to you. Please get in touch!


Eric Geringas
Versioning producer. Documentary filmmaker. Factual TV director. Problem solver.