What is Rotoscoping?

Rotoscoping is drawing a moving mask around a subject, frame by frame, so it can be separated from its background. It is the groundwork for compositing, background replacement, selective colour, and placing text behind a person.

Category
Creative & Video Production
Also called
Roto, Rotoscope, Masking
Related
CompositingPaint-OutScreen Replacement
In our work
VFX & Cleanup

A mask has to follow the subject through every frame of a shot, which is why rotoscoping used to be among the most time-consuming jobs in post-production. AI masking tools now produce a usable first pass on many shots in a fraction of the time.

The hard cases are unchanged: hair, motion blur, semi-transparent edges, and objects that cross in front of the subject. A mask that is slightly wrong on those edges shows up as a flicker or a halo, which is why a compositor still checks and refines automated roto frame by frame.

Common questions.

Why does rotoscoping take so long?

Because the mask has to be right on every frame, and a single second of video is 24 to 60 frames. Hair, fast motion, and anything that passes in front of the subject need the most hand correction, even when an AI tool did the first pass.

Is rotoscoping the same as green screen keying?

No. Keying separates a subject from a coloured background automatically, using that colour. Rotoscoping draws the separation by hand or with AI assistance when there is no green or blue screen to key from.

Related terms.

  • Compositing

    Compositing is combining elements from different sources, such as a filmed subject, a replaced background, a screen insert, or a generated object, into a single image that reads as one shot.

    Creative & Video Production

  • Paint-Out

    Paint-out is removing something from a shot that should not be there, such as a logo, a boom microphone, a rig, a crew reflection, or a blemish, and filling the space so the removal cannot be seen.

    Creative & Video Production

  • Screen Replacement

    Screen replacement is placing new content, such as an app interface, a website, or a video, onto a phone, laptop, or monitor screen in footage after it was filmed.

    Creative & Video Production

Scoping a project?

Reading definitions because you are scoping a project? Skip ahead and just ask.

Tell us what you needBack to the glossary