The main column of my website is 500 pixels wide.
Lately for whatever reason, for certain videos Youtube only provides
width options that go down to 560 pixels or so.
Fortunately, it's never been hard to show a video at whatever size you wish, you just have to do a bit of math and fiddle with a few parameters. This miniapp takes care of that - just paste in any existing embed code and indicate the width you want. (This seems to work on most tag-based things that use width= and height= attributes in logical ways)