When watching flash movies, for example BBC Iplayer, ubuntu allows my screen to dim and switch off.

I do not want to change my settings so that it waits an hour or so for my computer to be 'idle' as I do wish to save power etc.

It already knows when I am watching a movie in totem or something and blocks the computer from going idle, I would like this to also work for flash movies.

I see that a lot of sites use flash for content that is not movies, so possibly only allow the flash to block idle when the browser is visible on the screen, i.e. non minimised.