Thanks for your interest.
The video format is flv (FLV1), simply because Limesurvey has a button for inserting flash elements. Similarly the code we used was just that generated when you click that flash button and choose a file uploaded to the server:
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,40,0"><param name="quality" value="high" /><param name="movie" value="/limesurvey/upload/surveys/333312/flash/test.flv" /><embed pluginspage="http://www.macromedia.com/go/getflashplayer" quality="high" src="/limesurvey/upload/surveys/333312/flash/test.flv" type="application/x-shockwave-flash"></embed></object>
However, this doesn't work. The file doesn't even play in the preview box, and when I preview the question it simply shows a blank box where the video should be. Right-clicking on the box gives me the message "Movie not loaded..."
I tried some code I found for embedding youtube videos:
<object height="315" width="420"><param name="movie" value="http://www.youtube.com/v/5fP4emqw7O4?hl=en_GB&version=3&rel=0" /><param name="allowFullScreen" value="true" /><param name="allowscriptaccess" value="always" /><embed allowfullscreen="true" allowscriptaccess="always" height="315" src="http://www.youtube.com/v/5fP4emqw7O4?hl=en_GB&version=3&rel=0" type="application/x-shockwave-flash" width="420"></embed></object>
This worked fine for the youtube video but not at all when I tried to adapt it to run a video off of our server.
In case it helps, we're using Version 2.00+ Build 121213.