You cannot avoid the subjectiveness of HDTV; The ITU-R BT.709-5 (latest version -2002-) defines:
The executive summary is not a definition, nor is, as the iteration you quote, a footnote in a section on color space a definition to resolution.
HDTV is a set of standards. It is not subjective. To address any concerns that 720p is a uniquely American phenomenon, I refer you to the EBU (*European* Broadcasting Union) Technical Committee: "
a minimum of 720 vertical lines(PDF)"
I'll also refer you to the (groan) Wikipedia article on HDTV, which has a very clear chart that accurately reflects the embodiment of international standards:
here
Finally, I'll refer to Samsung's excellent guide for beginners:
here
ATSC and DVB both define SDTV and HDTV standards (there is no such thing as EDTV except in marketing), and all 720 vertical-line formats and higher are classified as HDTV per A/53.
Actually, if you were following the controversy, you should remember that the issue wasn't that 720p wasn't 'high definition', it was that they objected to the inclusion of multiple resolutions and formats in the standard. In other words, they urged "HDTV" to be defined as 1920x1080 progressive and nothing else. 720p would have to be called something else, as would 2160p, as would 1080i. As history has played out, that view did not prevail (for better or worse). They objected to 1080i being called HDTV for about a decade before revising their position to "just 1920x1080"--but within a few years, they'd lost that argument, too.
But this is more considered to be enhanced TV rather than HD (like 480p60).
Considering that neither ATSC nor DVB, let alone ITU-R, EBU, ISDB, or the FCC, have any idea what "enhanced TV" is, I think we all can move on. "EDTV" is marketing and nothing else. SDTV and HDTV are the only two officially recognized kinds of DTV worldwide.
The distinction is clean and intuitive as it actually exists. 480/576 formats are SDTV; 720p and higher are HDTV. Splitting the resolutions around a convoluted scheme of framerate and color space, including some but not others is needlessly complex and detracts from the central and immediate difference between HD and other content: resolution. Since 720p and 1080i share the same approximate effective vertical resolution (due to idiosyncrasies in the production of most 1080i), it would be odd to separate them in that way. I can see how you would come away from reading on ITU-R BT.709 with that impression, since it is dominated by issues of colorspace reproduction (i.e. predominantly sRGB), not by broadcasting (ATSC/DVB) or image production.
yeh but come on, what is the main point of editing HD - to deliver it in the most natural format, which in 2008 is probably disc.
still i agree in principle with what you say
I think it's more accurate to say that the point of editing HD is to preserve as much of the original content as possible so that when moving to final production, your final encoding is the only source of quality loss. Delivery in the "most natural format" as of today would still be DVD, so encoding for DVD would entail a loss of HD. As has been said, however, HD-DVD players can play back properly encoded HD video from a DVD.