The basic concept behind Motion Tracking and Stabilization is to follow an object as it moves around from frame to frame in a piece of footage. Once you understand how it works, you can:

•Stabilize the footage: If you know this object was supposed to be in the same place from frame to frame, but it moves for some reason, After Effects can track the object's movements, then animate it to move on the exactly the opposite direction so it appears to be steady.

•Have one object follow another : If you know how an object is moving through a scene, you can then make another object of your choosing follow the exact same path. Check out my tutorial on Basic Tracking for more information.

To do this, you need to show After Effects a “feature region” in the footage for it to track. The best features have clearly defined, consistent shapes with distinct edges. They also have contrasting color or brightness compared with the pixels around them. After Effects has the ability to adapt what it is looking for from frame to frame, but the less the feature changes size or shape the better.

Once After Effects has this initial idea of what to look for, it looks inside a user-defined “search region” for the same feature in the next frame of footage. Once it finds it, it resets the location of these regions and looks at the next frame. The tighter you can define these regions, the faster and more accurate the track.

Basic Video Stabilization in After Effects CS3

1. While previewing the footage, look for items that might make good features to base your stabilization on: something that has good contrast, that keeps roughly the same shape and position throughout the shot, and that isn't obscured by another object. In this tutorial, I'll choose the top of one of the poles. The tip of the pole and the surrounding sky definitely have different luminance values.

2. In the upper right corner of the application window, click on the Workspace popup and select Motion Tracking. This will open the Tracker Controls panel.

3. Double-click the clip itself to open it in its own layer panel. Click Stabilize Motion in the Tracker Controls and a track point will be created. Both tracking and stabilization need to take place in the Layer panel so that you can focus on just that clip. Once the clip is loaded into the Layer Panel, you'll notice that the Motion Source automatically changes to this layer's name.

4. The track point consists of two boxes and a crosshair: The inner box is the feature region, which you will use to enclose the feature you wish to follow. The outer box is the search region, which tells After Effects how far to search in the next frame for a group of pixels that matches what was in the feature region in the previous frame. The crosshair in the middle of these boxes is the attach point. It is the center for any stabilization that takes place. When tracking it defines where the Anchor Point for the new layer will be placed.

5. Drag the inner feature region to the spot that is the easiest to follow according to the qualities in Step 1. Drag the inner feature region just large enough to enclose your feature. Drag the search region a little larger than the feature region. If you drag a corner, the regions will all move symmetrically around its center. To move just one corner, press Cmd/Ctrl while dragging.

6. In the Tracker Controls click on Options. Make sure that you verify your options time to get the desired result. The first option that you come across is Channel. Set this based on how you feature stands out from the pixels around it. In this case, the sky is an orange hue, so I will pinpoint the dark pole sticking up. The brightness between them are considerable different, so I will choose Luminance.

You can usually leave Process Before Match disabled; use it only if you have trouble tracking. If the footage is out of focus, enable it and try Enhancer; if it is noisy, try Blur.

You also always want to leave Subpixel Positioning on, and most of the time you want to leave Track Fields off. If you feature constantly changes shape or size every frame, be sure to have Adapt Feature On Every Frame on. I will also set the popup to Adapt Feature and leave Confidence at 80% to tell After Effects to keep it's eye on the same feature unless it thinks it has changed too much.

7. Click on the Analyze Forward button in the Tracker Controls. After Effects will search each frame for the feature you've defined. When it is finished, you will see a motion path created for Track Point 1. In this case, it's individual points are bunched together, as the feature doesn't move that much. By pressing U, you can actually see all of the keyframes that were just made.

8. In the Tracker Controls, make sure Track Type is set to Stabilize and motion Target is set to your video clip. Click Apply and a Motion Tracker Apply Dimensions dialog box will open. Leave the default of X and Y Dimensions and click OK. After Effects will bring the Comp panel forward and add a set of Anchor Point keyframes in the Timeline panel. These Anchor point keyframes offset the movement detected for youor feature region, causing the footage to be stabilized. Ram Preview

9. If your background color is peeking through now because your footage is no longer centered, then create a solid (Layer>New>Solid) to put behind the video clip. Click on the Make Comp Size button, and eye dropper a color from around the edges of the footage.

10. Wala – Stabilized Footage:)

Corey Richards's Background
With a background as a video editor, videographer, 3d modeler/animator, web designer, and graphic artist, Corey is about as diverse as they come. As the Director of Web Services for the DVPA, Corey ensures that the DVPA community stays well informed of the surrounding news and changes in the industry.