The first step is to download the AE project and footage from the
tutorials page here.

Open up the comp and select the
that is the single layer in the timeline. Go to
the Animation menu and select . Note that in
some cases you might want to scale the footage up by 10 percent. As AE
stabilizes the motion, the frame will shift, resulting in white space
around the edges. In our case, all the white space is outside the
action safe area.

This opens up the movie in a separate tracking window, with the
tracking UI and widget. The tracking widget is a "+" symbol (the
crosshairs) within a small square, all of which is inside a larger
square.

The tracking widget’s crosshairs determine the tracking point and the
layer is offset relative to this point. You don’t want to move the
crosshairs during stabilization or tracking. It’ll completely distort
the results. Once you’ve found a nice home for it, leave it alone. If
you find you need to adjust it, you’ll need to restart the tracking
process.

The smaller box defines the pattern that the tracker is looking for.
The MT works by taking this pattern and looking for it in each frame.
When you’re stabilizing footage, it finds this pattern and moves the
entire frame so the pattern falls in exactly the same spot as it did in
the previous frame. How much the frame has to be moved is the offset
amount. The goal is to have the tracker locate this pattern in each
frame and have the MT line the pattern up so that every frame has it in
the same location. (More on how to select the pattern in Step 4.)

The larger box is the search area. This is the area that the MT will
look in for the pattern. Be warned: the larger you make this, the
slower the MT will be and the more likely a similar but different
pattern will be found. This will make the MT jump off track. But you do
need to make this large enough that the pattern will be found in all
frames. If the footage is really jumpy, the search area will have to be
larger than the search area for footage with only a slight jitter. You
can change search areas as the track progresses. If the footage is only
jumpy for a second, you can make the search area larger or change the
pattern for just those frames.

The key to motion tracking or stabilization is to find a pattern that
is unique in the search area and is easily identifiable by the MT. Not
by your eye, but by the MT’s calculations. People can easily identify
all sorts of patterns and track them. Computers handle this task
literally and it’s not something they excel at. But a pattern that’s
easy for a computer to keep track of has several key attributes: 1)
high contrast; 2) sharp, perpendicular edges; 3) no repetitions; 4) is
not obscured during the length of the footage.

This is where the black art of motion tracking comes in. The pattern
doesn’t have to have all these attributes, but the closer you get to
fulfilling them, the easier the job will be. Also, since the footage
re-positioned each frame to line up the pattern, you end up with
transparent areas around the edge. In this case, that’s only going to
be noticeable on the extreme edges outside of Action Safe. If the
movement is more noticeable, you might want to scale the footage up by
5 to 10 percent.

Click and drag in the small square and move the crosshairs so they are
on the corner of one of the buildings in the lower, right corner of the
image.

This spot worked well for me, but there are other spots that would have
worked too. Modify the small square a bit, as shown, then shrink the
large square down so it forms a loose fit around it.

Make sure the Time Marker is at 00:00 and hit the play button on the Tracking Palette.

Sometimes it takes some trial and error to find a good tracking
pattern. The pattern I used should work extremely well, but try and
find another one. If you don’t find a good pattern, our tracking point
will lose its way. The crosshairs start wandering away from the cluster
of points that were created in the first part of the footage. If you
can’t get it to work there are a couple of things to try.

If your original pattern changes (like the lighting in this footage)
you may need to make adjustments. Sometimes, this is as easy as
enlarging the pattern square a little. Sometimes it requires some
creative thinking. (Notice I didn’t say "requires thinking outside the
box." In some parts of the world uttering bad, overused clichà©is cause
for imprisonment, forced labor and listening to Vogon poetry.)

The pattern square does not have to be centered around the crosshairs.
If you enlarge the search area to include the entire building we can
select a different pattern, such as the large, bright window below our
original pattern.

In each case you’ll need to press the play button on the Tracking
Palette to start the process. Remember not to move the crosshairs
themselves. This will mess up the stabilization.

Once you get the track done, click the Apply button. This will transfer
all the tracking info to your Anchor Point position and offset the
layer as needed.

Now you can close the tracking window and go back to your main comp.
You should have a nicely stabilized piece of footage. If you still have
a little bit of jiggle you can try starting the process over from
scratch. Don’t worry; it took me a couple of tries to find a good
tracking spot. You can also pre-comp your footage and apply a new
stabilization to that.

After Effects stabilizes footage well, but sometimes, you’ll still have
just a little bit of jitter. Applying stabilization a second time will
get rid of it. Think of it as two-pass stabilization: one-pass to get
rid of the shaking, and another pass to get rid of the smaller
sub-pixel jitters.

That’s it! If you’re still having trouble you can go into the Finished
Comp and double click on the Tracker 1 that’s applied to the
layer. This will open up the MT window and show
you exactly where I positioned the tracking point.

Jim Tierney
President
Digital Anarchy

Jim Tierney has worked on numerous award-winning products from
companies like MetaCreations, Atomic Power and Cycore. After working on
Adobe After Effects plug-ins for almost a decade, he thought it was
finally time to get out there and do some of his own. As "Chief
Executive Anarchist," Jim conceptualizes and designs Digital Anarchy
products.

Motion tracking and stabilization can seem like a bit of a black art.
But it’s really not as difficult as it first might appear. The Motion
Tracker/Stabilizer in After Effects, while still not exactly on a par
with Shake or Flame, will bring fluid movement to a jittery piece of
footage.

The original raw footage I used here comes from stock agency Thought
Equity (www.thoughtequity.com). This is a
cropped, SD resolution chunk of one of their HD time-lapse stock clips.
The footage needed to be stabilized before it would actually be useful
to anyone.

After Effects’ Motion Tracker/Stabilizer is much improved from earlier
versions and for the vast majority of jobs it works very well. We’re
going to discuss the stabilization features of the Motion Tracker, and
then tackle tracking in a future tutorial. The techniques for
stabilizing and tracking are the same, but tracking requires some
additional work. Unfortunately, none of the stabilization techniques
work with mentally unstable clients. That’s a completely different
tutorial.

Digital Anarchy
www.digitalanarchy.com
218 Cordova Avenue
San Francisco, CA 94112
ph. 415.586.8434
jim@digitalanarchy.com