Understanding the tracker plug-in options (Pro only)

After Effects includes several options to help improve your success in tracking. These options are available using the built-in tracker plug-in. You access these options by clicking the Options button in the Motion Tracker Options dialog box. This opens the Tracker Plug-in Options dialog box. (See Defining tracker options (Pro only).)


Tracker Plug-in Options dialog box

Use Channel

Specifies the comparison method to use for tracking:

• RGB compares the RGB values in the feature region. Select if the feature is a distinct color.
• Luminance compares the brightness value in the feature region. Select if the feature has high contrast, or brightness, compared to the surrounding objects and background (such as a burning candle carried through a room).
• Saturation compares the density of color in the tracking region. Select if the feature has a high concentration of color, surrounded by variations of the same color (such as a bright red scarf against a brick wall).

Process Before Match

Temporarily blurs or sharpens an image to improve tracking. Select Blur to reduce noise in the footage. Usually a value of 2 to 3 pixels is enough to produce better tracks in grainy or noisy footage. Select Enhance to exaggerate or refine the edges of an image and make them easier to track.

Note: After Effects blurs or enhances the footage only for tracking, restoring it to its original state after tracking.

Subpixel Positioning

Specifies fractional position keyframes to match the specified feature region. When deselected, the tracker rounds off position keyframes to the nearest pixel.

Extrapolate Motion if Confidence is Below _%

Specifies a tolerance level for matching the feature, after which After Effects extrapolates the motion. In other words, if the accuracy of the frame-to-frame match falls below the specified percentage, After Effects estimates the position of the Feature region. Use this option if the feature is obscured by another object or temporarily blends into the background. For example, if you are tracking a dog that walks behind a tree, the tracker can calculate the position of the dog in those frames where it is blocked by the tree.