Track failure means the tracker stops before the end or falls off the target. Failures are a natural result of the track pattern changing with camera movement. Although Live compensates for pattern changes, the quality typically drops off toward the end of the track. You can see this occurrence graphically in the Track Summary.
There are various approaches you can try to correct track failure. In general, keep in mind these important settings on the Track control panel:
With this method, the goal is to track from the opposite end until your track data meets in the middle with the beginning track data. For example, if you started forward, move to the last frame where the point is visible and track backward.
To avoid overwriting the valid track data, change Stop Tracking On to Better Frame or User Tracked Frame. Also, be careful to avoid jumps where the forward and backward tracking meet; you may need to reposition the tracker yourself.
If the track quality dips in the middle, try choosing Bidirectional as the Tracking Direction. Bidirectional tracks both forward and backward from the selected frame. This method is also useful to continue tracking a feature that fails toward the end.
To avoid overwriting the valid track data, change Stop Tracking On to Better Frame or User Tracked Frame.
Resize the target or search box
The tracker can fail, drift off track, or jump to other objects if the target or search box are not sized properly. See Size track boxes for guidelines on resizing. You may need to resize the target or search box on the failed frame or start over with a new size.
Be careful to keep the track box cross-hairs positioned over the same part of the feature as the original target.
Position the track box yourself
In some cases, you may save time by positioning the track box yourself. For example, if the object you are tracking becomes blurry and then clear again, try positioning it yourself on the blurred frames and then restart tracking when it is clear. Remember to click the track box tool to enable manipulation of the track box. Also note that the Track Summary draws a blue line to indicate you have positioned the track box on a given frame.
If the previous techniques do not help, see Track Options panel for other settings that may improve tracking.
You should delete the tracking data if the feature falls out of view or is poorly tracked. For example, the feature may become obstructed by another object or move out of the camera’s view.
Delete the frames even if they are in the middle of the tracking. If you don’t, these problems will negatively affect your solution.
To delete tracking data frames
Press Ctrl+Alt and drag the mouse around a zoom region. Drag from left to right.
Delete and deactivate track points
You can permanently delete track points or temporarily deactivate them. To delete them, use the Delete key, the Edit > Delete option, or the Delete button on the Track control panel. To deactivate them, turn off the Active checkbox on the Track control panel.
Deleting a track point removes affiliated 3D locators from all solutions. If the point is used in any survey constraints, Live forces those constraints to be inactive. In this case, you need to recreate the constraint.
