Apple Shake 4 Tutorials - Manual (Page 210)

210 Chapter 7 Tracking and Stabilization
The search region is too small to encompass the movement in the clip—the bus moves
too far to the right. In this illustration, the desired area, artificially marked in green,
extends beyond the zone of the tracker search region (the outer red box).
If the search region is too large, you waste time processing. If the search region is too
small, the tracker does not find successful matches. There is also a black line around the
sign along the bottom of the pattern. There is a chance due to the perspective shift in
later frames that the tracker will confuse the two lines. Adjust the search area with
these problem areas in mind.
9 Go back to frame 1.
10 Grab the corners of the search region and scale it outward, but shrink the bottom up
up a bit. Also, scale down the reference pattern to better fit the corner.
Note: When adjusting the tracker boxes, grab an edge to adjust just that edge. Grab a
corner to scale the entire box. Grab the center to move everything. What is adjusted is
highlighted in yellow.
11 Click the Track Forward button.
Any previous keyframes are written over.