The problem is that anything written in Shockwave or Flash normally needs the Flash Player to run it. In particular FLV files, (Flash Video), are made specifically for the Flash Player plugin in browsers.
If a web site allows these videos to be downloaded, then you can use the VLC Player to play .flv files, but to see the videos in web pages you are pretty much stuck with the Flash player plugin. It is what the web page demands to play those files.
Personally I don't know of any alternatives, so I use as much caution as I can if and when I want to play such files in the browser.
I've been reading about all the security problems adobe flash player causes in cnet tech news, and wonder if there's an alternate flash plug in for firefox?