Editing Marks in a Video Sequence

Editing marks manually is always necessary in a motion capture project. In a given frame, mark editing is the same as in a digitizing project. In addition, these functions are expanded to include editing marks and points appearing in both multiple videos and in multiple frames. The following lists the methods to edit marks across frames:

1. Add a mark to a point sequence: First select a current point in a frame. Then click the right mouse button on a image in another frame. This will add a mark to the current point. It is usually easier to select the current point in the Aux window, then add the new mark in the Image window of the current frame. An alternative way is for you to select the current point in the Image window, then use the Video Control to change the frame. Next, use the right mouse button to add the new mark.
2. Delete marks from a point sequence: First, select (-left button) marks to be deleted in an Image window, then use one of the following Mark menu commands in the Image window to delete the selected marks in the image.
   • [Mark|Delete selected|from current frame]
   • [Mark|Delete selected|from current and subsequent frames]
   • [Mark|Delete selected|from previous and current frames]
   • [Mark|Delete selected|from all frames]

3. Delete selected points is similar to deleting marks. Start by selecting marks, then use one of the following Point menu commands in the Image window to delete the points of the selected marks. Corresponding marks in other images and in other videos will also be deleted.
   • [Point|Delete selected|from current frame]
   • [Point|Delete selected|from current and subsequent frames]
   • [Point|Delete selected|from previous and current frames]
   • [Point|Delete selected|from all frames]

4. Merge two points: To merge point B into point A, first select point A as the current point. Then click the right mouse button on point B while the key is pressed.

5. Break a point sequence in two: Suppose we have point A appearing in 1 to 10 frames and the current frame is 4. We can break this point sequence at the current frame by:
   1. selecting it as the current point, and;
   2. invoking the menu [Point|Break].
   This will break point A into two points: point A will be in 1-3 frames and a new point X in frame 4-10. This function can be used when mark tracking starts to track the wrong point in a particular frame in a sequence.

6. Separate marks from a point sequence: Suppose we have a point with marks in video A, B, C. We can separate marks in video A from this point by:
   1. selecting it as the current point, and;
   2. invoking menu command [Point|Separate] in the Image Window of video A.
   This will separate the point into two points: the current point will only appear in video B and C. All the corresponding video A marks track another point. This function is handy when two point sequences are merged incorrectly.

When the feature points are not obvious in videos, tracking may not work in some frames at all. In this case, manual editing becomes the only choice.