Tracking Difficult Shots			Stabilizing
Chapter 25, Tracking and Stabilizing

Topics on this Page:

Updating the Reference Point

Resetting the Tracker

Adjusting the Tracker Box

If the tracker box strays from the reference point that it is supposed to be tracking, incorrect keyframes result. If such an error occurs, you can stop the analysis, correct it, and restart it at any frame.

There are a number of different methods you can try to correct tracking errors. Try the strategies given below, then redo the analysis to generate new keyframes based on the updated information you provide.

Updating the Reference Point

If the tracker loses the reference point, you can delete the incorrect keyframes, then, at the last good keyframe, update the reference point to the current contents of the tracker box.

1. Select the appropriate tracker by clicking the appropriate Tracker button.

2. Press Backspace.

   The last keyframe is deleted and the positioner moves back one frame. The tracker box is now on the previous keyframe.

3. If you want to remove this keyframe, press Backspace again.

4. Repeat step 2 for all incorrect keyframes.

5. When you reach the last good keyframe, click Snap. This updates the reference point from the one originally specified in the reference frame to the image currently inside the tracker box.

6. Click Analyze to continue the tracking process.

Resetting the Tracker

If the tracker loses the reference point early in the analysis, you may want to reset the entire tracker and find a new reference point--see Resetting the Tracker Box.

Adjusting the Tracker Box

If the Stabilizer cannot find the reference point within the boundaries of the tracker box during analysis, the tracker box strays from the reference point and produces incorrect keyframes. Although you can manually correct these keyframes, it is easier to make the tracker box large enough to accommodate the movement of the reference point. Note that processing time increases as the size of the tracker box increases.

1. Stop the analysis by clicking the Analyze Forward button.

2. Press Backspace until you reach the last good frame before the tracker box strayed from the reference point. Adjust the size of the tracker box, so that it is large enough to accommodate the largest frame-to-frame movement of the reference point.

   Note: Backspacing deletes the keyframes as you go back. If you do not delete the keyframes, they will be overwritten when you reanalyze. Backspacing in this instance makes it easier to see the tracking path clearly.

3. Click Analyze Forward to continue the analysis.