Has anyone ever noticed how the actual displayed resolution of video on the YouTube website is 449 x 337 pixels? Really strange values. So if you create video and your target is the YouTube website, you may want to use those values if you don’t want any resizing artifacts. When you upload a video to PooTube, their servers convert it to 320 x 240 pixels, and after that the flash-player fucks it up (stretches it out). I would advice to downsize the video you upload yourself, it will probably be better quality than the way YT does it for you.
I also noticed how their “embed” object code gives even stranger values:
width=”425″ height=”350″
which is a ratio mismatch conversion of their default video-size either way. In fact, if you post a YouTube video on your own website (like I do sometimes), the grey flash-player control part is different from that on the YouTube site itself (it’s smaller), which is another parameter to take into account.

The embed code should actually have these values if you want to make the video look like how it is shown on YT:
width=”449″ height=”369″
and the embed code should have the following values if you want your video to look most like the original upload:
width=”320″ height=”259″
(Note that these size-values appear in the embed code twice.) I’ve tested this in both linux and Windows browsers, using the latest shockwave/flash-player plugins.