Sometimes you want to ensure your viewers are getting the best viewing experience from YouTube. Here's how to link directly to full-screen and HD versions of your video.
We're not sure when it was disabled, but the old &fmt= suffix doesn't work any more for determining resolution on YouTube. Here's what does work at the time of writing.
Replace the watch in the URL with watch_popup.
Add &vq=hd1080 to the end of the URL for 1080p.
Add &vq=hd720 to the end of the URL for 720p.
Note that the video will have to exist in these resolutions for the URLs to work, and these tags must be used in conjunction with watch_popup.
Bonus: start the video at a specific time
Add #t=0m0s to the end of the URL, replacing the zeroes where you want the clip to start.