The Stabilize behavior uses a sophisticated motion analysis to track every pixel from one frame to the next to smooth shaky motion in a video clip or image sequence. Unlike the Match Move and Analyze Motion behaviors, the Stabilize behavior does not use onscreen trackers to analyze motion. However, if the result of the analysis requires additional correction, you can manually add onscreen trackers to noncontiguous segments of the clip. For example, if an accidental camera bump affects frames 350 to 380, you can add a tracker to analyze that portion of the clip. The data recorded from the analysis is added to the data recorded by default analysis to further smooth the clip.
In addition to considering horizontal, vertical, or horizontal and vertical movement in the clip, the Stabilize behavior looks at position, scale, and rotation. The Stabilize behavior can only be applied to footage objects in your project (QuickTime movies or image sequences).
For information on using the Stabilize behavior, see Stabilize a shaky clip.
After you apply a Stabilize behavior to a clip or image sequence, the Behaviors Inspector displays the following adjustable controls:
Source: A source well to designate the source object supplying the tracking data used to stabilize the clip. By default, the clip you apply the Stabilize behavior to appears in this well, ready to be analyzed. However, you can manually drag a different source object into the well—another Stabilize behavior in your project or even a different footage object in your project. To clear a Source well, drag the thumbnail away from the well and release the mouse button.
Action pop-up menu: A pop-up menu (with a gear icon) to manually assign tracking data (from other tracking behaviors in your project).
Movement-Analyze: A button to activate a 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.
When using the Stabilize behavior (without trackers), the track begins at the start of the clip, rather than the current playhead position.
Quality: A pop-up menu to define the level of detail in the motion analysis. There are two options:
Faster: Allows for a faster operation, but motion analysis is less detailed.
Better: Provides a more detailed analysis, but is slower. This is the recommended option when the clip contains rotation.
Track Region: A checkbox that, when selected, lets you manually define an area in the frame to be analyzed. A red overlay appears in the canvas. The area outside this overlay is ignored by the analysis. The track region’s onscreen controls are similar to a shape’s onscreen controls, allowing you to modify the size, shape, and position of the track region.
For more information on setting a track region, see Stabilize a shaky clip.
Method: A pop-up menu to define how the stabilization is applied to the clip. There are two options:
Stabilize: Attempts to lock the motion of the principal subject in the shot to eliminate motion. As a result, the background appears to move around the subject being tracked.
Smooth: Smooths the apparent motion of the camera, while allowing the general movement in the frame to proceed. Use this method to remove camera jitter.
Translation Smooth: A slider (available when Method is set to Smooth) to smooth motion in the X and Y dimensions.
Rotation Smooth: A slider (available when Method is set to Smooth) to smooth image rotation.
Scale Smooth: A slider (available when Method is set to Smooth) to smooth an uneven zoom.
Note: Don’t set the Scale Smooth value above 0 unless you’re positive the clip is being zoomed.
Borders: A pop-up menu to set how moving border artifacts are handled. When you stabilize a clip, the resulting transformations may cause moving black borders to appear around the edges of the clip. Stabilized clips containing extreme horizontal or vertical movement (due to excessive camera shake) may result in very large black borders. There are two Borders options:
Normal: Maintains the size of the stabilized footage. The moving black borders remain around the edges of the clip.
Zoom: Expands the clip to fill the canvas. This prevents black borders from appearing around the edges, but scales up the stabilized clip, which may degrade image quality.
Tip: You can also eliminate the black borders manually by adjusting the layer’s scale or Z position in the Properties pane of the Inspector.
Direction: A pop-up menu to specify the dimensions in which the recorded movement are applied—Horizontal and Vertical (X and Y), Horizontal (only X), or Vertical (only Y).
Adjust: Three buttons to set the type of transformation applied. Select any combination of the three:
Position: Stabilization is applied to the position of the analyzed image.
Scale: Stabilization is applied to the scale of the analyzed image.
Rotation: Stabilization is applied to the rotation of the analyzed image.
Tracker: An Add button to add trackers to the Stabilize behavior. By default, trackers are added at the center of the canvas. You can add a maximum of two trackers to the Stabilize behavior. The first tracker you add is the Anchor tracker, used to analyze changes in X and Y position. The second tracker you add is the Rotation-Scale tracker, used to analyze changes in rotation and scale.
When you add trackers, the following occurs:
The Track Region parameter is no longer available.
The Reverse checkbox becomes available, allowing you to analyze a clip backwards from the playhead position (in reverse).
The Tracker Preview, Offset Track, Auto-Zoom, Auto-Zoom Mode, Look Ahead Frames, and track list controls become available. For more information about these controls, see Match Move controls.
Note: When another behavior is used as the source for the stabilization, you cannot add trackers to the Stabilize behavior.