- The "Girl" clip

About this Tutorial

The mokey stabilizer has a number of controls that allow you to achieve several different effects. This tutorial will show you how to: -

• Remove camera shake from a tracking shot
• Fill in border regions blanked out by the motion compensation
• Smooth the camera motion
• Achieve the effect of a locked off camera
• Set fixed frames

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This is an interlaced clip, so when you open it, set the Interlaced settings to Separate Fields with the Lower Field First option. Set the frame Offset to zero. Use mask values Top 4 pixels, Bottom 2 pixels to mask out the noisy rows at the top and bottom of the image.

Selections

First make a selection of the beach in the first field. This will be used as the background when filling the blank border areas of the image. Extend the selection to the left to allow for the motion in later frames (this can also be corrected later). Now make a selection of the girl, using a small selection around her body and head. The motion of her arms and legs is too erratic to be tracked accurately.

Image 25 - Selections in field 0

Tracking

Track the selections through the clip. If the selection of the girl starts to drift from being centered on her body and head, stop tracking and correct the contour (hint: drag with the right mouse button to move all the points at the same time). Continue tracking to the end of the clip.

Stabilization

First select the Girl selection to be stabilized and stabilize the clip using the default settings. The girl should now remain fixed in position throughout the shot, emulating an accurate tracking shot.

To fill in the blank borders switch on Auto Fill and repeat the stabilization. This will fill in the blank regions as far as possible, using the motion of the tracked background selection to determine how to move pixels between frames.

Note that in the first frame the pixels on the left side cannot be filled because they would require frames "before" the start of the shot.

Another way of using the mokey stabilizer is to stabilize on a background selection, thus achieving the effect of a locked off camera. To fix the camera in its position at the first frame, set the first frame as a key frame.