[This question is off-topic for tor-dev, which is for development *of* tor. Please take future usage questions to tor-talk@ instead.]
Are you certain that the video in question is using Flash? Browsers have native video support nowadays. It's difficult to tell for certain without breaking out the webpage debugger, but you can make an educated guess based on the contents of the menu that appears when you right-click on the video. Flash videos normally have "About Adobe Flash Player" or similar at the very bottom of that menu, and native browser videos normally don't (however, the contents of the menu are somewhat under the control of the page, so this isn't a waterproof test).
zw