Help me understand PowerPoint 2010 disabled options

The disabled options have me confused?

  1. Change the source file (from the original .avi you selected)
  2. Change the starting point (say start at 30 seconds)

I can see that those toolbar options are disabled (below) but I cannot see the reason.

Figure: Why can't I 'Trim Video' but others can http://www.dkszone.net/how-to-embed-format-and-edit-videos-in

Figure: Why can’t I ‘Trim Video’ but others can http://www.dkszone.net/how-to-embed-format-and-edit-videos-in

Figure: Why are these options in the toolbar disabled?

Figure: Why are these options in the toolbar disabled?