Footage in Paint*
recently had the opportunity to shoot a friend's college graduation
on video. Like most of these sort of things, I had about three
days notice and was forced to shoot under less than ideal conditions.
Mostly, the big problem here was camera shake. There wasn't
space to set up a tripod, so I used one of those lap monopods
with the knowledge that some camera shake would be induced by
things like me shifting in my seat. But, I knew I would be editing
it later, and that I could clean up some of the camera shake
by stabilizing it in Paint at the same time.
still using the same setup I was when I wrote my earlier tutorial
on Effect*, so I'm accessing my video as Targa frame sequences
on my DPS Perception. Unfortunately, because of the length of
the ceremony before editing, I couldn't capture the footage
at the best quality my PVR supports. Instead, I had to capture
at the best quality that would fit on the PVR's dedicated drive.
I took the main footage and trimmed it into several separate
sequences based on the planned edit points. I also trimmed the
audio because I won't be changing the length of the sequence,
so I can use my editor to attach the audio from the non-stabilized
sequence. (This is because the PVR stores its audio and video
as separate files, the audio is stored on a system drive while
the video is stored on the PVR's dedicated drive. DPS uses a
file called an Audio-Video Clip [.AVC] file to store the location
of both files so their player utility will play both simultaneously.)
footage loaded into Paint* I then opened the image sequence
in Paint* with and set the appropriate pixel aspect ratio in
the File > Footage Settings Window (PVRs use D1 pixel
aspect ratio.) Since the sequence was a bit long, it would take
awhile to track each sequence (sigh, the only disadvantage)
If I were using Edit* version 5.0, I could simply set up the
track and save the project settings then import the clip as
a project into Edit*, saving myself the trouble of the image
getting recompressed twice (compressed once on capture, again
with the stabilized sequence, and again after editing.) But
alas, Discreet does not support DPS products directly like they
do with Truevision's (now owned by Pinnacle) Targa series, and
the Matrox DigiSuite.
Stabilize 2 points window. Next, I went into the Effects menu,
and selected Stabilize >Stabilize 2 points... because I intended
to use more than one point in the image to provide stabilization
data, and to stabilize for rotation and scaling as well as position.
Positioning the first Stabilize point Once again we come to
the arcane practice of finding tracking points in the image.
Remember, this time the points not only have to have enough
contrast and relative stability (i.e. there are no major changes
in the tracking point, no one walks in front of it etc.) but
they also have to show where the motion is you want to stabilize.
In this case, my first tracking point went along the upper edge
of the podium right where the microphone crosses the edge. To
do this, click on 'pick' next to 'Stabilize point 1' and manually
position the stabilization point crosshairs. Then, you will
need to turn the tracker on for 'Position' and create a tracking
point on the Stabilize point you selected. you can now adjust
the tolerance for the tracker for this point, including the
size of image it uses for the track. Keep it fairly tight because
you don't want the stabilization to wander.
you position the tracker, position the Analyze button in the
tracker palette and track the footage from this point. Positioning
the tracker on the second Stabilize point. Next, I selected
a second tracking point. This time, I picked an outer corner
of a planter halfway across the platform. The nice black
planter provided a lot of contrast against the platform itself,
and the corner stayed a clear enough structure throughout this
part of the shot.
I positioned the stabilizing point, I activated the tracker
and analyzed the footage just as I did with the first point.
After a bit of experimentation, I decided to move the point
to the back edge of the table cover, because with the stabilization
set to 'fit' mode, the field separation of my video footage
became too apparent with the points being so close together
Also, another thing
I noticed is the need to make large tracker boxes. I ended up
going back and making the tracker boxes twice the size that
you saw above in order to get the fit of the image correct.
But, it did stabilize the footage.
Included here are two mpegs, before and after stabilization.
Click the left side of the image for the before clip, and the
side for the after clip.
Jon Carroll is
a freelance animator, illustrator and production designer located
in Richmond, VA. He can be reached at [email protected]