Troubleshooting Manual Tracks

Even with manually positioned tracks, some sequences are inevitably going to cause problems. There are a number of pre-tracking checks you can perform to assist C_Tracker:

• Play through the sequence before placing your tracking anchors.

• Look for features that are consistent throughout the majority of the sequence.

• Avoid occluded features where possible - see Dealing with Occlusions.

Tip:  You can also add auto-tracks to improve the result further. See Automatic Tracking for more information.

To troubleshoot manual tracks:

1.   First, turn on the color-coded error indicator by clicking the traffic light Viewer tool .

Each keyframe is colored on a sliding scale from green (good match) to red (poor match).

A red keyframe doesn’t necessarily mean that the tracking result is poor, only that C_Tracker couldn’t reliably match the pattern from one keyframe to the next.

2.   Move the tracking anchor to the first of the poor frames, just about the center of the image in the example.
3.   Using the zoom window, drag the anchor to the correct location of the grabbed pattern.
4.   Advance the playhead to the next poor keyframe and repeat until the track is complete.

When you're happy with the number and distribution of tracked features, you can solve the camera and then use the results for stabilizing or match-moving. See Solving Cameras for more information.

Dealing with Occlusions

C_Tracker’s offset capability allows you track an obscured feature using the relative position of another feature, providing that the distance between the two points remains constant.

1.   Track the pattern normally until the occlusion causes Tracker to fail.

The zoom window helps to identify the failure point.

2.   Play though the sequence to identify a likely offset point - a pattern that remains equidistant from the original pattern grab.
3.   Hold down Ctrl/Cmd and drag the tracking anchor to the offset position.

The offset amount is recorded in the Tracks list and highlighted in yellow in the Viewer.

4.   Continue tracking as normal by clicking the track backward (Z) or forward (V) button.

Tracker combines the two tracks into a single continuous track.

5.   Use the clear backward and forward buttons to clear poor keyframes. Click clear all to remove all keyframes.

Note:  You can reset tracking anchor pattern and search areas by clicking .