Motion uses behaviors to collect, analyze, store, and apply tracked motion data. Because the data is stored in the behavior (as keyframes), it can easily be applied to other objects in a project. A Motion Tracking behavior can also be used to apply animation data created by standard behaviors or keyframes. Motion Tracking behaviors are applied in the same manner as all other behaviors.
When a tracking behavior performs its analysis, track points appear in the Canvas, and tracking keyframes are created in the behavior. These keyframes live in the behavior that is applied to an object—the keyframes are not applied to the object itself.
Note: Onscreen track points (and their corresponding tracking keyframes that appear in the Keyframe Editor) are not created when using the default motion analysis in the Stabilize behavior.
There are four Motion Tracking behaviors:
Note: The Analyze Motion behavior can only be applied to footage (a QuickTime movie or image sequence).
The Analyze Motion behavior lets you add multiple trackers to a clip. In this way, you can analyze multiple reference patterns at the same time.
You can match a foreground element to a background element using one-point (position), two-point (position, scale, or rotation), or four-point (corner-pinning) tracking. Unlike other tracking behaviors, the Match Move behavior can perform the analysis and compositing operations. You can add further modifications (blur, color corrections, and so on) before you create the final composite.
You can use the Match Move behavior to apply a reference a track recorded by another tracking behavior. You do this by choosing a track from the Action pop-up menu (the gear icon) in the Match Move behavior’s HUD or Inspector.
You can apply the animation data of one object (animation created by behaviors or keyframes, for example) to another object. You do this by dragging an animated source object from the Layers list into the Source well in a destination object’s Match Move behavior HUD or Inspector. In this way, you can apply the animated source object’s movement to the destination object without analyzing the motion of the source object.
Note: The Match Move behavior can be applied to nearly any object type.
The Stabilize behavior can analyze and stabilize a clip without onscreen trackers. In this case, the Stabilize behavior evaluates the entire frame of a clip using motion analysis to record the movement of the camera. This behavior offers two ways to use this recorded data: clip smoothing, which eliminates unwanted jitter while maintaining the general motion of the camera; and clip locking, which stabilizes a subject. This behavior can analyze and affect position, scale, and rotation.
In addition to full-frame motion analysis, you can add onscreen trackers for one-point (position) tracking or two-point (position, scaling, or rotation) tracking. When you add manual trackers to the Stabilize behavior, Motion stabilizes the clip using data from the trackers rather than from an automated motion analysis. When using this method, the tracker moves the frame so the track point falls in the same spot in each subsequent frame. You can also combine these methods; for example, you can track part of a clip with the full-frame method and then switch to manually added trackers later on.
You can load analysis tracks recorded in one Stabilize behavior into another. To load an analysis track, choose a track from the Action pop-up menu in the destination object’s Stabilize behavior HUD or Inspector.
Note: The Stabilize behavior can only be applied to footage (a QuickTime movie or an image sequence).
Note: The Unstabilize behavior can be applied to nearly any object type.
When applicable, you can convert tracking data recorded or referenced by the Match Move, Stabilize, or Unstabilize behaviors to object keyframes. When converted, the tracking behavior is removed and the transform keyframes are “baked” into the object. For more information on converting behaviors, see Converting Tracks to Keyframes.