The bigger problem here is that, from experience on one particular site, it seems hard to rank text-less Flash and video content unless it has a voiceover. I know a lot of the time it's a pointless excercise for users but it seems to be essential for most search engines. Part of that I think is that with no text, you can't do relevant internal links.
Actually to qualify that, I got a reasonable ranking for the main site term but getting any longtail term to rank was a major problem. I haven't found the solution after 4 years of trying. Well, I did in the end - by adding meaningful but ultimately pointless text to each page. This is a scenario where - if your flash/video is engaging - you wish user metrics were more a factor.