If you upload your videos to YouTube — or most video sharing sites for that matter — there isn't much you can do to improve them after the fact. Starting today, though, YouTube will finally provide basic tools to make your kitty videos suck less.
YouTube is rolling out the new feature in the form of a simple "Edit Video" button on your My Videos page. It's a little like if they just took their cloud-based editor and sucked it back into the site. All you have to do is select one of your videos, and it'll let you trim away excess footage, rotate, stabilise to get rid of shake, and changes the attributes to make things brighter, warmer, or more saturated. You can also add Instagram-style filters to make things look old-timey. And when you're done, the video won't lose views and its link won't change. All is right with the world. Thanks, guys.
Unfortunately, the new tools can't be used on uploads that have more than 1000 views or have a Content ID claim on them. In those cases, you'll have to re-upload (and, at that point, why?). But, while it's not the most robust of feature sets, it's a definite improvement as it lets you add a little something to your vids.