User Manual

Once you’re satisfied with your track, you can continue to resize, reposition, or reshape the
window being tracked. Tracking data is separate from the window transform parameters (which
can be keyframed), so changes you make to a window offset it from the originally tracked path.
Tracking Windows When You’ll Be
Exporting Media With Handles
When you track windows to match moving features in a clip, the windows are only transformed
on frames with tracking data. In Round Trip workflows where you add handles to the graded
clips you render for editorial flexibility in the footage you deliver, you need to make sure that
you track all windows from the beginning to the end of these handles to make sure that, if an
editor actually trims any of the clips you give them to use the handles, all windows are doing
what they should.
An easy way to do this is to choose View > Show Current Clips With Handles to display each
clip you select in the Timeline with handles defined by the “Default handles length” setting in
the Editing panel of the User Preferences. Make sure that the “Default handles length” is equal
to the handles you export using the “Add X Frame handles” option in the Render Settings list of
the Deliver page. With each clip’s handles made visible in this way, you can easily track
windows along every frame you’ll be rendering.
Simple Ways of Working With Existing Tracking Data
If there’s a portion of a shot that you haven’t tracked (for example, you started tracking at a later
frame, or you ended tracking before the end of the shot), then the window you’re tracking
remains wherever it was at the first or last frame that was tracked. If you want to fill in these
gaps, you can always move the playhead to the first or last frame that was tracked, and then
use the Track Backward or Track Forward command to track the rest of the frames in that shot.
Tips for Better Tracking
In situations where a feature changes shape in such a way as to confuse the tracker, you can try
tracking a smaller part of the feature by using a smaller window. Once you’ve achieved a
successful track, you can resize the window as necessary, and it will have no effect on the track
that’s already been made.
Also, if you’re tracking a feature that moves behind something onscreen and disappears for the
rest of the shot, there’s an easy way to avoid having an awkward window sitting in the middle of
the scene. You can use dynamic keyframes to animate the Key Output Gain parameter (in the
Key tab of the Color page) to fade from the correction’s full strength of 1.0 down to 0, the value
at which the correction disappears, along with the window itself.
Tracking One Frame at a Time
You can click the “track one frame forward” or “track one frame backward” buttons in the
Tracker palette to track a moving feature one frame at a time, making it easier to make
adjustments to follow a difficult track when you’ve set tracking to Frame mode (by clicking the
Frame button).
In Frame mode, you can keyframe window transformations to more faithfully conform to
troublesome motion as you’re moving one frame at a time through the track; manual changes to
a window’s position will be keyframed to create frame-specific transformations, rather than
used to offset the entire tracked motion path as in Clip mode. When you add multiple keyframes
in the Tracker graph, animation will be automatically interpolated from keyframe to keyframe.
Chapter – 121 Motion Tracking Windows 2740