2011

Table Of Contents
About Tracking and Stabilizing
Understanding how to use the Tracker tool and apply the tracking data to
elements in a composition, and determining to which parameters you want
to apply the tracking data are key factors for producing basic to complex
effects. The more experience you gain from using the Tracker tool and applying
tracker data to elements, the more you see all the effects that trackers can
produce. If your composition is jittery, use the stabilizing feature within the
Tracker tool or the Panner tool to remove, for example, unwanted camera
jitter.
Tracking and stabilizing are often processes of trial and error. You should track
or stabilize with default settings, and if the tracker box strays, fine-tune the
analysis.
Much of the tracking and stabilizing work you do will be done using the
Reaction supertoolsee
Reaction Compositing and Effects on page 240, and
the 2D Transform Toolsee
2D Transform Tool on page 432.
Tracking Concepts
The Tracker is a tool for following and capturing the motion of an on-screen
feature, and then applying that stored motion to a second element, so that
the two appear to be locked together.
You can track any number of features in a length of footage:
1-point tracking Tracks a single feature for position.
2-point tracking Tracks two features, using the relationship between the
two to track scale/rotation.
4-point tracking Tracks four features, also referred to as corner pinning.
Multiple-point tracking Tracks as many features as you want.
You can apply the stored motion to various elements:
Center point of an object For example, you could track a halo over the
head of a person in a clip. Assume that in the clip a woman tilts her head and
advances toward the camera. You would want the halo to reflect the position,
scaling, and rotational changes of the tracked features on the woman's head.
NOTE When you track scaling, you are not performing 3D tracking in true Z-space.
You are simply measuring the amount of change over time in the size of the tracked
object.
754 | Chapter 32 Tracking and Stabilizing