5

Important: The Analyze Motion behavior can only be applied to footage objects (a
QuickTime movie or image sequence).
Parameters in the Inspector
Movement: The Movement parameters contain the Analyze and Reverse controls.
• Analyze: This button, when clicked, begins the motion tracking analysis. When you
click Analyze, a status window appears and displays the tracking progress. To stop the
analysis, click the Stop button in the status window or press Esc.
The start of the track is based on the current playhead position, rather than the start
of the behavior in the Timeline.
• Reverse: This checkbox, when selected, reverses the analysis direction, going from the
playhead position to the first frame of the clip (or the first frame of the tracking
behavior).
Note: You must move the playhead to the frame where you want the reverse analysis
to begin.
Tracker: This button lets you add trackers to the Analyze Motion behavior. By default,
one tracker is available. New trackers are added at the center of the Canvas.
Tracker Preview: This preview area provides a magnified view of the tracking reference
area for the selected tracker. The preview updates as you adjust the position of the tracker
in the Canvas. You can drag in the preview area to adjust the position of the tracker.
When dragging in the preview area, the image moves around the red crosshair that
represent the tracker, while the tracker moves in the Canvas. You can also Option-drag
left or right to decrease or increase pattern size. (You can also adjust the Track Size slider
to achieve the same result.)
Offset Track: This checkbox lets you select a new reference point when the original
reference point becomes temporarily hidden or goes off the screen. Motion uses the new
tracking point to continue the same tracking path as the original reference point. For
more information on offset tracking, see Tracking Obscured or Off-Frame Points Using
Offset Tracking.
Auto-Zoom: This pop-up menu lets you choose a magnification level when positioning
the tracker in the Canvas. You can zoom in on the Canvas when searching for an ideal
tracking reference pattern. There are four choices: None, 2x, 4x, and 8x.
Auto-Zoom Mode: This pop-up menu lets you set the display of the auto-zoomed tracker
in the Canvas. There are three choices:
• Normal: Displays a normal pattern.
• Contrast: Displays the tracker pattern with contrast detection.
• Edge: Displays the tracker pattern with edge detection.
The Auto-Zoom Mode applies to trackers in the Canvas and does not appear in the
Tracker Preview in the Behaviors Inspector.
1342 Chapter 22 Motion Tracking