If anyone is interested in open source semantic temporal audio/video metadata in mediaWiki take a look at the metavidWiki extension. I just posted a screen cast ... still a few weeks away from public launch but you can check out the preview now:
http://metavid.ucsc.edu/blog/2007/12/18/short-metavidwiki-extension-screenca...
if your *really* interested come by #metavid on freenode (like most projects) we could use more testers / whatever level you interested in getting engaged at ;)
peace, michael