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greg_mitch
Joined: 03 May 2006
Posts: 5320
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| Posted: Sun Apr 26, 2009 3:14 pm Post subject: What defines HDTV? |
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The ATSC standard document A/53 really defines broadcast standards. I don't see it talking about resolution.
SMPTE has standards on almost every resolution and film including 1280x720p and 1920x1080p but they don't refer to them as HDTV as far as I can tell.
Who owns the HDTV trademark and what is the actual definition?
I have heard in the past that HDTV was only defined by a minimum vertical resolution of 720.
Is 1024x768 technically HD with rectangular pixels like on the 42" and under plasma sets?
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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greg_mitch
Joined: 03 May 2006
Posts: 5320
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| Posted: Mon Apr 27, 2009 2:21 am Post subject: |
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Lol...that is worse than a Wiki reference. 
When I searched through ATSC document A/53 I didn't see any requirements for "HDTV".
Have to look at ITU-R....
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greg_mitch
Joined: 03 May 2006
Posts: 5320
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| Posted: Mon Apr 27, 2009 2:34 am Post subject: |
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Edit...cant post...
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Mon Apr 27, 2009 5:05 am Post subject: |
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Greg... HDTV is just part of the ATSC DTV spec... Not sure why you couldn't find it... Took me about 3 seconds. 
http://www.atsc.org/standards/a_53-Part-1-2007.pdf
| Quote: | High-definition television (HDTV) – High-definition television has a resolution of
approximately twice that of conventional television in both the horizontal (H) and vertical
(V) dimensions and a picture aspect ratio (H × V) of 16:9. ITU-R Recommendation 1125
further defines “HDTV quality” as the delivery of a television picture which is subjectively
identical with the interlaced HDTV studio standard.
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Then, in this document:
http://www.atsc.org/standards/a_54a_with_corr_1.pdf
| Quote: | high-definition television (HDTV) High-definition television provides significantly improved
picture quality relative to conventional (analog NTSC) television and a wide screen format
(16:9 aspect ratio). The ATSC Standard enables transmission of HDTV pictures at several
frame rates and one of two picture formats; these are listed in the top two lines of Table 5.1.
The ATSC Standard also enables the delivery digital sound in various formats. |
Table 5.1 defines resolutions supported in the ATSC standard:
1920x1080@24P, 30P, 60I
1280x720@24P, 30P, 60P
and 480i/p.
The most important thing is that "HDTV" isn't a standard per se. The SMPTE standards (274M, 296M, 293M) define the signals themselves, and together are collectively "HDTV" within the ATSC DTV spec.
SC
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greg_mitch
Joined: 03 May 2006
Posts: 5320
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| Posted: Mon Apr 27, 2009 6:09 pm Post subject: |
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Because you are smarter than me (are you happy now?! )
So there is no spec for HDTV.
The real question came up is 1024x768 considered HD?
ITU says at least 1125 lines so no it isn't.
(BTW I was looking in part 4 jerk)
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ralpharch
Joined: 02 Nov 2007
Posts: 211
Location: Derwood
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| Posted: Mon Apr 27, 2009 8:16 pm Post subject: |
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| greg_mitch wrote: | Because you are smarter than me (are you happy now?! )
So there is no spec for HDTV.
The real question came up is 1024x768 considered HD?
ITU says at least 1125 lines so no it isn't.
(BTW I was looking in part 4 jerk) |
Way back when I bought my RCA MM36100 it was labled a "high resolution" display since it was capable of only 930 (H) x 1080i - which did not meet the then somewhat accepted of needing to be able to resolve somewhat over 1 million "pixels" or the equivalent
I believe that later on the plasma/LCD manufacturers started calling the square pixel 1024x768 displays HD versus Enhanced definition (EDTV versus HDTV.
And then there were a whole lot of CRT direct views sold with 850 or so horizontal resolution that were called HDTVs.
So it appears that the "standard" (assuming there ever was one) got relaxed down into the 800000 range with passage of time.
No way a year or two later would RCA market a TV like the MM36100 as high resolution; "with the ability to display high definition material within 1440x1080i 4:3 window" - it would have been called HD from the start.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Mon Apr 27, 2009 9:08 pm Post subject: |
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| greg_mitch wrote: | | Because you are smarter than me (are you happy now?! ) |
Whew. At least we finally have that out of the way. 
| greg_mitch wrote: | | So there is no spec for HDTV. |
Not that I'm aware of. Beyond the ITU/SMPTE broadcast standards, "HDTV" is a really a general trade label that refers to a TV image significantly better than old SDTV. I couldn't even find any official "HDTV" logo... The one we see with the blue "H" and the "checkmark V"... In my brief research, I couldn't find anything that indicated the origins or any owning or governing body. It's like somebody made the thing, and everybody just started using it (or variations of it).
| greg_mitch wrote: | The real question came up is 1024x768 considered HD?
ITU says at least 1125 lines so no it isn't. |
I agree. XGA isn't HD. It's twice as much resolution as SDTV, but only what, 75% of 720p... It's not 16:9, either - which I think is kind of a given for something to be HDTV. Not sure about the 1125-line thing, though... That refers to the analog broadcast version of what we call 1080i, now... 720p is HDTV by any standard I've ever read, but it certainly wouldn't qualify as "at least 1125 lines".
| greg_mitch wrote: | | (BTW I was looking in part 4 jerk) |
Regardless of where you were looking, it wasn't in the right place, was it..... butthead!?!?
SC
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Angus_rg
Joined: 16 Dec 2007
Posts: 339
Location: A planet far, far away..... Baltimore, MD
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| Posted: Mon Apr 27, 2009 9:30 pm Post subject: |
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| ecrabb wrote: |
I agree. XGA isn't HD. It's twice as much resolution as SDTV, but only what, 75% of 720p... It's not 16:9, either - which I think is kind of a given for something to be HDTV. Not sure about the 1125-line thing, though... That refers to the analog broadcast version of what we call 1080i, now... 720p is HDTV by any standard I've ever read, but it certainly wouldn't qualify as "at least 1125 lines".
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A lot of plasma's used xga as 720p, and they looked better than many LCDs that were 1080p because they had crappy deinterlacers, scalers, etc.
How many people here would rather have a CRT displaying an XGA image stretched to 16x9 over a 1080p LCD? I think the true measure of HD is, does it look better than what I am replacing, rather than some standard I had no say in.
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Curt Palme
CRT Tech
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| Posted: Mon Apr 27, 2009 9:59 pm Post subject: |
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My spec is when you think you can actually reach out and touch the models in 'Bikini Destinations'
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Angus_rg
Joined: 16 Dec 2007
Posts: 339
Location: A planet far, far away..... Baltimore, MD
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| Posted: Mon Apr 27, 2009 10:10 pm Post subject: |
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| Curt Palme wrote: | My spec is when you think you can actually reach out and touch the models in 'Bikini Destinations'
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I just ordered that DVD. Time for some nightly calibrations. 
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WanMan
Joined: 19 Mar 2006
Posts: 10270
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| Posted: Wed Apr 29, 2009 9:30 pm Post subject: Re: What defines HDTV? |
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| greg_mitch wrote: | The ATSC standard document A/53 really defines broadcast standards. I don't see it talking about resolution.
SMPTE has standards on almost every resolution and film including 1280x720p and 1920x1080p but they don't refer to them as HDTV as far as I can tell.
Who owns the HDTV trademark and what is the actual definition?
I have heard in the past that HDTV was only defined by a minimum vertical resolution of 720.
Is 1024x768 technically HD with rectangular pixels like on the 42" and under plasma sets? |
I am not sure anyone owns the HDTV trademark. Also, HDTV is more of a CEA convention than one from the FCC. Even the FCC is limited to what they adopt, and hence the ATSC adoption. As a result of all of this, you get a lot of abuses in the HDTV department.
Some of the early flat-panels claimed HDTV because it a) had a minimum of 480 progressive lines and the screen fit the 16:9 aspect ratio (employing non-square pixels).
From the perspective of broadcasters in the USA I think their adoption has been 1280x720P and 1920x1080i, but these are only two of the approximate 18 formats in the ATSC specification.
Buit the bigger question is ... whay are you asking, Greg?
And this topic has been asked by me almost 8-9 years ago. Not bad for something the FCC started adopting 14 years ago.
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Thu Jun 11, 2009 2:44 pm Post subject: |
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| ralpharch wrote: | | greg_mitch wrote: | Because you are smarter than me (are you happy now?! )
So there is no spec for HDTV.
The real question came up is 1024x768 considered HD?
ITU says at least 1125 lines so no it isn't.
(BTW I was looking in part 4 jerk) |
Way back when I bought my RCA MM36100 it was labled a "high resolution" display since it was capable of only 930 (H) x 1080i - which did not meet the then somewhat accepted of needing to be able to resolve somewhat over 1 million "pixels" or the equivalent
I believe that later on the plasma/LCD manufacturers started calling the square pixel 1024x768 displays HD versus Enhanced definition (EDTV versus HDTV.
And then there were a whole lot of CRT direct views sold with 850 or so horizontal resolution that were called HDTVs.
So it appears that the "standard" (assuming there ever was one) got relaxed down into the 800000 range with passage of time.
No way a year or two later would RCA market a TV like the MM36100 as high resolution; "with the ability to display high definition material within 1440x1080i 4:3 window" - it would have been called HD from the start. |
Enhanced definintion was typically used for 480p displays. Since vertical resolution is more perceivable by humans than horizontal, plasmas used to use the rectangular pixel "trick" to lower cost. So many plasmas that were 16:9 were 1024x768 or 1024x1024. Both of these are considered "high definition".
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A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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