Every html5 video I try to play online plays at double/1.5x speed (very useful when trying to fastforward through a video, not great otherwise). I can slow it down to half speed (e.g. on YouTube HTML5 player), but can't get it back to normal.
The weirdest part is that it's not just one browser: it's every browser on my computer. (and clearing cache, etc doesn't really help). Flash video still works fine.
I'm using Ubuntu 12.04 (specifically Lubuntu, but I'm guessing it doesn't make a difference).