Not really. Simply do not autoplay videos, just like Flashblock allows you to not autoplay Flash. I already had a MPlayer plugin for Mozilla Seamonkey back in the days, and its same story with it. Unfortunately, there was no consensus on which video and audio codec HTML 5 should support which is rather sad. Apple preferred H.264, Mozilla preferred OGG Theora and OGG Vorbis, and Nokia... well from what I remember they said their previous mantra that OGG is patent encumbered.