This is an example of using panZoom to remove the captions in a video, and then replacing them with smilText. This example was tested on Windows Ambulant 2.2 on Wine on PCLinuxOS 2010.

PanZoom="left, top, width, height"

The panZoom effect on a video did not work on Linux Ambulant 2.2 plugin but panZoom on an image did.

There is also a switch element used for the videos:
switch
theora video
webm video
/switch

It looks like webm will be the primary free codec I put it in the switch element. Since Ambulant doesn't support webm yet, Theora is placed in first.

panZoom Example no prefetching used
Webm Video, keep the Web Free