From GizmoTech's YATTA guide
that never got finished:
IVTC Patern Matching:
So you're asking yourself, "Well Bludgers, how do I find a pattern in a scene"? There are really 2 easy ways to quickly find pattern. They involved tracking down an "NcccN" pattern.
First Method: Fast action
Identify a point in the scene (perferably near the start) where a hand/arm/body moves. Identify the first point of movement where it N matches, then set the next 3 frames C and hope that the next frame is a N match. Assuming all goes well, you've just identified a NcccN pattern, which, when moving to the next frame and Activating Auto Patern allows you to just play through the rest of the scene confident in knowing you've achived pattern.
Second Method: Mouth Transitions
The more dificult way, is to identify changes in mouth sizes. Alot of mouth transitions are done in frames of 5, which make identifying mouth transitions usually quite fast. Find a change where a mouth goes from big(er) to small(er) (or vice versa) and make sure it is an N match. Set the next 3 frames to C, and then the 4th frame, in theory, should be a N match on a nother transition. Assuming you were lucky and hit a NcccN pattern, you can now activate auto pattern and finish out the scene automatically.
Now an important point of note. In most cases a scene will NOT change pattern from start to finish, however there are rare occasions where the scene will change pattern mid stream.