2017

Table Of Contents
How the Stabilizer Works
The Stabilizer uses trackers to generate tracking data. Each tracker consists of a solid box, called the reference
box, and a dashed box, called the tracker box. The reference box establishes the reference point (the feature
to track or stabilize) in any frame of the sequence. The tracker box indicates to the Stabilizer where to locate
the reference point. The tracker box follows the frame-to-frame movement of the reference point.
(a) Tracker number (b) Tracker box (c) Reference box
You start by selecting one or more reference points on your clip. Locate the first frame containing the
movement to be tracked (the reference frame). In general, the reference frame is the first frame of the
sequence. The choice of the reference point depends on whether you are tracking or stabilizing. When
tracking, the reference point is a feature you want to track; when stabilizing, the reference point represents
the point around which the image is stabilized. See
Selecting a Reference Point (page 720) for details. Place
the reference box(es) around the selected feature(s).
Once you have set the tracker positions, start the tracking process, also referred to as analyzing the clip.
During the analysis, the tracker box associated with each tracker moves as the Stabilizer looks for a pattern
that matches the reference in each frame of the clip.
The Stabilizer calculates the difference between the position of the tracker box and the position of the
reference box to produce X and Y Shift values. Shift values represent a measurement in pixels and subpixels
of how much the reference point has moved.
718 | Chapter 17 Stabilizing and Tracking