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?

Add captions for images

Microsoft Word currently supports attaching captions to embedded images, as seen in the following screenshot. This cannot be done with embedded images in Microsoft PowerPoint, however. It would be useful if users could add captions to PowerPoint images as well.

 

 

Figure: Microsoft Word's image pop-up menu includes Caption command

Figure: Microsoft Word’s image pop-up menu includes Caption command