Tracking

You can use the Stabilizer to make a clip or part of a clip track an object in another clip. For example, you can paste a logo to the side of a moving car. You can track a clip using one, two, or four reference points:

In one-point tracking, one reference point is tracked to produce 2D motion without rotation or scaling.
In two-point tracking, two reference points are tracked to generate translation, scaling, and rotation data that is applied to the foreground composite.
In four-point tracking, the tracking data generated from four reference points is used to lock the four corners of a bilinear surface to the background in Action.

Since tracking involves compositing at least two clips, you open the Stabilizer from Action. When loading the clips in Action, you load the clip that contains the pattern you want to track as the back clip. The method for selecting the object that follows the pattern on the back clip is different for four-point tracking than it is for one and two-point tracking. Both methods are explained in the following sections.

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