For either broadcast video or Internet streaming video, rotoscoping is the rotated projection of a sequence of usually photographed action image frames so that the artist can trace from the frame or create an image to superimpose on it. It can be thought of as "painting on movies" efficiently. Prior to computers, an animation stand called a Rotoscope was used to project a sequence of action frames against a surface so that a set of animation frames could be traced or created. The same work can now be done with digital images and special computer software. Tools that provide efficient ways to rotoscope include Digital Magic and Elastic Reality. Rotoscoping is frequently used as a technique for combining (compositing) cartoon figures with realistic settings in television commercials and is also used for special effects in feature-length films.
A rotoscoping texture (sometimes called a sequence map) is the use of video within an animation, something like an animation within an animation. For example, in a cartoon animation, the television set could show a program containing another animation. Or in a background to an animation in the foreground, you could include some clouds that slowly changed during the foreground animation. The frame rate for both the main animation and the "animation within the animation" must be the same.