The traditional approach to lip synching is to define facial expressions, with specific mouth and lip positions called 'key shapes' or 'frames,' and then to identify which shapes are needed at points along the sound track. This has to be done in perfect sync with the audio track and the words a character is saying. Changing Face of Animation To get an idea of how difficult this is, Riley says to look in the mirror and say a word. In animation, for each one of the different mouth shapes, an artist needs to create a model of a cartoon character holding that specific position. While today's animation software can interpolate movement and animation between shapes, it's a labor-intensive and mundane process.
Animators typically place a key shape on one out of every five or six video frames.
Face2face, however, allows for direct animation. After creating a character, animators need only to videotape an actor speaking lines. Face2face also makes producing multilingual versions of a cartoon easier and more efficient. And because face2face requires only an S-VHS or better video source with the actor's nostrils visible, animation can actually be done at the PC level. The software runs on Windows, SGI, and Linux platforms.