I'm working on a site right now where I have a bunch of vimeo videos.
The problem I ran into now is that they don't have the same aspect ratio all of them, so I decided to remove the WIDTH and HEIGHT parameters from the iframe and let the FitVids script do the fitting instread.
The problem now is that I get black bars on both videos, and I rather not have them if it's possible.
Please have a look at my demo here:
You should probably leave the heights and widths on there. FitVids grabs those and makes the surrounding box match those aspect ratios, avoiding the black bar problem.