Instruction Manual

Chapter 22 Motion tracking 971
Combine masks with tracking behaviors
When a mask is added to an object with applied tracking data, the data is applied to the mask. In
the following image, the foreground object is tracked to four points on the background clip, but
still must be masked to t into the picture frame.
By masking the image being tracked, you can include only the portion of the image you want to
t in the frame.
Although the mask is attached to the foreground image, you might need to animate changes in
the mask’s position and scale to accommodate changes in the background clip over time.
Note: As an alternative to using masks, you can also crop an object with applied tracking data
using Crop controls in the Properties Inspector.
You can track the control points of a mask to a clip or apply existing tracking data to the control
points of a mask. For more information, see Track Points workow on page 974.
Stabilize workow
Use the Stabilize tracking behavior to smooth shaky motion in a movie or image sequence. For a
full description of Stabilize parameters, see Stabilize controls on page 1001.
With the Stabilize behavior, there are three ways to analyze a clip:
•
Use the default advanced motion analysis technique that evaluates the entire frame of a clip
at once to extract movement data without onscreen trackers.
•
Use onscreen trackers that analyze a reference pattern (a small group of pixels) in the Canvas.
These are the same trackers used by the Match Move and Analyze Motion behaviors.
•
Use a combination of the advanced motion analysis and onscreen trackers.
Important: For information on using onscreen trackers with the Stabilize behavior, see Basic
strategies to improve stabilization on page 990.
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