2-point
stabilizing is useful when the motion you want to remove involves changes
in scale/rotation (zoom/roll). For example, your camera may be zooming
out from someone in a rocking chair.
As in tracking, when
you choose to stabilize combinations of position, scale, and rotation
simultaneously, the roles of each of the points are additive:
- If you track both scale and rotation,
the first point indicates the pivot point of the rotation; the second
indicates the arc of the rotation; and the distance between the
two indicates the scaling changes.
- If you track position at the same time,
the first point also indicates the vertical/horizontal motion you
want to eliminate.
- If you track scale, choose two reference
features that are at the same Z-depth throughout the shot. For example,
if you have two rows of trees lining a driveway, choose two trees
at about the same Z-depth (distance away from camera).
- If you track rotation, choose two reference
features that are as far as possible from each other. This gives
the Tracker the maximum amount of roll to analyze and correct.
- If you do 2-point stabilizing, each of
the two reference features stays fixed throughout the stabilized
clip. That is, if you are stabilizing scaling, the scaling change
is eliminated. If you are stabilizing rotation, the rotation is eliminated.
To perform 2-point stabilization:
- Track the video clip using a Tracker
node with 2 trackers.
- Connect the clip into a Transform2D node.
- Set Transform Type to 2 Point.
- Click on Set Source Trackers and choose
the 2 trackers.
- Click on Set Destination Trackers and
choose the same 2 trackers, but select the frame number to which
you want the clip stabilized. This will set the destination points
to a non-animated value, positioning the stabilized clip to match
the desired frame. Alternatively, you can just edit the values of
the Destination 1 and 2 boxes to create the desired stabilized position.
- Click Link.
- Play the clip. The unwanted motion is
eliminated.
NoteYou can also perform
4-point stabilization by adding 2 extra tracker analyzers.