Thanks for the reply Russell.
I think I have found a slightly tedious way.
My friend, may eventually want to play his Impress presentation on an iPad, so as Windows girl, I was goggling to find what he should have his movie file types as.
Anyway, I came across this web page:
http://guide2office.com/1456/how-to-ext ... s-and-mac/
So for Impress:
1.Backup your .odp file
2.Rename your .odp to a .zip file
3. Extract the .zip file. Look at the contents of the zip file.
In the above article for PowerPoint, it shows the movie file names in the media folder:

But for my sample .odp, the media file has only the image files eg. jpeg, .png files
But, if you use a text editor, eg Notepad++ (helps to have XML plugin to may it easier to read), to look at the
content.xml file, you will see something like this:
<draw:plugin draw:mime-type="video/x-ms-wmv" xlink:href="../
lyrebird.wmv" xlink:type="simple" xlink:show="embed" xlink:actuate="onLoad"/>
A little tedious, but it does show you the movie file names used.
Thanks,

Margaret