This is just an attempt to explore some options that may exist with YouTube's embedded players. The following player has been defined as 560x200. But any other set of dimensions should also be possible.
This is an extension of the post made recently, speculating about the reasons for the appearance of the viewers on YouTube itself. I have to wonder... at least I have wondered for quite awhile, whether this isn't some subtle incentive for YouTube's users to focus on using embedded players, rather than sending them to YouTube pages more directly. It's a silly and overly complicated speculation, I know.
Oddly enough, this particular player embeds the video at its uploaded dimensions. In this case, the video was rendered at 1200x496 pixels... a 2.42:1 aspect ratio I mostly invented. The 560x200 player provides a 2.8:1 aspect ratio window... wider than the uploaded video. The result is the pillarboxing you see below.
Below the jump, I'll put up a 600x248 (+30px for the progress bar) player, which should be roughly a match to the video contained there... My apologies to any early readers of this post, which should probably not have been published before debugging everything. I'll try to follow this up with some more technical details on just how to determine the size of your embedded player, once I'm a bit more sure of what I'm doing here.
Below: Bringing widescreen options to YouTube. One crazy person at a time.
This player SHOULD be a half-size match to the original upload.
And here's another example... in this case the image and rendering were matched... this should show neither letterboxing nor pillarboxing.