open source, linux, and life.

[HQ18] &fmt=18 is video with _480x360 pixels resolution (_4:3 ratio) recorded at _512 kbps
[HQ22] &fmt=22 is video with 1280×720 pixels resolution (16:9 ratio) recorded at 2000 kbps
[HQ35] &fmt=35 is video with _854x480 pixels resolution (16:9 ratio) recorded at _900 kbps
[HQ37] &fmt=37 is video with 1980 x 1080 pixels resolution (16:9 ratio) recorded at _8000 kbs

&fmt=18 is what’s considered high-quality.
&fmt=22 is the standard for high-definition.
&fmt=35 is the true version of high-quality.
&fmt=37 is the true version of high-definition.

How to download 1080p off of youtube:

1. getfirefox.com
2. Download add on: https://addons.mozilla.org/en-US/firefox/addon/3006
3. Go to a youtube video which has 1080p available (for example: http://www.youtube.com/watch?v=XITHbsUUlYI)
4. Click on the download helper icon > and copy the url of one of the .mp4 videos

5.  paste into the url bar/awesome bar/download program and change “&fmt=22″ to “&fmt=37″ and your video should download.

“We’ve heard a lot of feedback around supporting HTML5 and are working hard to meet your request, so stay tuned. “

http://blog.thesilentnumber.me/2010/01/youtube-20-needs-your-input.html