480i is SD, technically (in marketing-speak) anything better than that is HD. In this case 480p is...

The PDF linked earlier mentions 720p, so it may only be the ustream that is limited to 480. source: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2011001...

From my understanding the cameras are HD, maybe they don't have the bandwidth to push HD video streams down from the ISS.

there is no standardized definition of HD. HDTV is 720 or 1080, but HD is simply a generic term meaning better than standard definition.

The only exception I've ever seen to the "HD >= 720 lines" rule is that of ignorant video uploaders.

do you have any official sources? I would love to update the related wikipedia page but can't exactly cite a hacker news comment.

The best I can find is this:

http://www.ce.org/CorporateSite/media/Standards-Media/DTV_De...

But it's consistent with your previous comment, in that it only defines HDTV, not "High Definition" as a generic term.

But given that HDTV is what caused "HD" to enter the vernacular, you'd have to be pretty dense to call something HD Video when it doesn't meet the HDTV standard. That would be like burning an .avi to a CD-R, and calling it a Digital Video Disc because it's a disc with digital video on it.

Interestingly, the PDF above suggests that you could have a 960x720 4:3 display that shows letterboxed 16:9 at 540p, and still call it an "HDTV".

480p is DVD quality