If, while preparing sample widescreen videos for the ‘YouTube/GooVid aspect ratios Howto’ you’ve been planning to make, you are suddenly mystified at how none of them are actually at the correct aspect ratio, I’d suggest that you make sure that your widescreen monitors are at the aspect ratio you thought they were.
It turns out that when I got my new Viewsonics to replace the off-brand LCD I had for a while before that, I assumed they were the same aspect ratio (1.78:1) as the old one. Turns out that at the resolution I’m currently using they’re actually 1.6:1. I’ve been both literally and figuratively pulling my hair out trying to figure out just why I had to stretch my videos to 2:1 to get them to display correctly, when I handcrafted them to need to be at 1.78:1 for proper display. Turns out it was a really simple misconfiguration problem that, had I not made some assumptions leading up to it, would have been the first thing I would have checked.
This is just another example of how when you “assume,” you can often make an “ass” out of “u.”