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Martha Stewart's cellmate
Guest
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 Posted:
Fri Dec 31, 2004 2:22 am Post subject:
Is 1024x 1024 true HD? |
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I'm confused, Dell's 42" plasmas say HDTV on their website but resolution is
listed as 1024 x 1024. Is this true HD, or upconverted to HD?
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Matthew L. Martin
Guest
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| Posted:
Fri Dec 31, 2004 2:34 am Post subject:
Re: Is 1024x 1024 true HD? |
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Martha Stewart's cellmate wrote:
| Quote: | I'm confused, Dell's 42" plasmas say HDTV on their website but resolution is
listed as 1024 x 1024. Is this true HD, or upconverted to HD?
|
Since the FTC is useless, there is no definition of HD displays. Some
manufacturers claim that 1024/768 in a 16:9 format are HD. I disagree.
If it isn't 1280x720, at least, I wouldn't consider buying it.
Matthew
--
Thermodynamics and/or Golf for dummies: There is a game
You can't win
You can't break even
You can't get out of the game |
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charper1
Guest
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| Posted:
Fri Dec 31, 2004 2:47 am Post subject:
Re: Is 1024x 1024 true HD? |
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If you have a standard analog TV, you'll see TV shows displayed in 480i
resolution. The 480 refers to the number of horizontal lines that make
up the picture. The "i" means interlaced, which means that half of the
lines are drawn in one 1/60th-of-a-second pass, then the other half of
the lines are drawn in another 1/60th-of-a-second second pass, to draw
the "full" picture every 1/30th of a second.
There are two DVD resolutions. The first is 480i, which uses the
interlaced method to draw the images onscreen. The second is 480p, also
known as progressive scan DVD. Progressive scan means that all of the
lines are drawn sequentially and in one pass, which creates smoother
images than the 480i picture. The progressive scan 480p image isn't
high definition, but it's the next best thing.
The main resolutions used to deliver HD programming are 720p and 1080i.
The 720p picture is drawn with the same method we discussed for
progressive scan DVD, giving you a picture with 720 horizontal lines,
each consisting of 1280 pixels. The 1280 x 720 resolution gives you the
16:9 wide screen aspect ratio that defines HD. The 1080i picture is
drawn in two passes using the interlaced method. However, because there
are far more lines in a 1920 x 1080 picture, the visibility of the lines
is reduced and the level of detail is increased. Some say 720p does a
better job with fast-moving images, while 1080i is the highest possible
HD resolution in terms of detail. At the end of the day, both
resolutions deliver a superior picture - nothing else comes close.
SO I JUST PLUG HD PROGRAMMING INTO MY TV AND I SEE THE HIGHER
RESOLUTION, RIGHT?
Not so fast. There are two issues when it comes to resolution: the
resolution of the signal being sent to the TV, and the resolution that
the TV is capable of displaying. This is where the native resolution of
your TV comes into play. The native resolution describes the amount of
vertical and horizontal pixels your TV can show. To display true 1080i
HD as it is intended to be seen, you need an HDTV with a native
resolution of 1920 x 1080 or higher. Many HDTVs can handle a maximum of
720p at full resolution, and 1080i programs are converted to fit their
screen. In addition, there are digital TVs that have lower than 1280 x
720 native resolution, but are able to convert and display both 720p
and 1080i images.
LONG STORY SHORT, WHAT DOES ALL OF THIS MEAN TO ME?
It means that you can read about HD resolution all the live-long day,
but the best way to understand HD resolution is by watching it. Go to
an electronics store and take a look at what's playing on the HDTVs.
Find out what the resolution of the programming is (Discovery HD
Theater, an electronics store favorite, is 1080i). Then decide what
degree of resolution is satisfactory for your viewing needs. Perhaps
you'll only be satisfied with a top-of-the-line model that allows for
maximum HD resolution. Perhaps you'll find an HDTV that has a lower
resolution but looks better to you for other reasons: contrast ratio,
color temperature, etc. It's time to take another trip down the HDTV
aisle and see the big picture for yourself.
--
charper1
------------------------------------------------------------------------
This message was posted via http://www.satelliteguys.us by charper1 |
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dg
Guest
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| Posted:
Fri Dec 31, 2004 3:17 am Post subject:
Re: Is 1024x 1024 true HD? |
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HD, as I consider it, is either 720P or 1080I. Neither of which can be
displayed in their entirety by a 1024x1024 fixed pixel display.
720p = 1280x720
1080i = 1920x1080
The displays probably look pretty good however, quite a bit better than
regular TV I am sure.
--Dan
"Martha Stewart's cellmate" <arnold@illbeback.com> wrote in message
news:jk_Ad.160793$8G4.109976@tornado.tampabay.rr.com...
| Quote: | I'm confused, Dell's 42" plasmas say HDTV on their website but resolution
is
listed as 1024 x 1024. Is this true HD, or upconverted to HD?
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42
Guest
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| Posted:
Fri Dec 31, 2004 6:08 am Post subject:
Re: Is 1024x 1024 true HD? |
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In article <charper1.1i3kdw@satelliteguys.us>,
charper1.1i3kdw@satelliteguys.us says...
| Quote: | It's time to take another trip down the HDTV
aisle and see the big picture for yourself.
|
Except that what you see is usually a batch of misconfigured TVs with an
array of different hookups and content, surrounded by vulture salesreps
who just want a quick sale and who have no more knowledge about the TV
than what is printed on the box.
The best looking TV is often the one they want to sell...
It would take literally hours on each TV side by side to do a proper
comparison.
On the upside, if you see a TV that you like in the store, at least
there is a good chance you'll like it when you get home... but all those
TVs that you passed by because they had 'inferior pictures' might just
have been configured badly or plugged into a crappy signal source... |
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Karyudo
Guest
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| Posted:
Fri Dec 31, 2004 8:15 am Post subject:
Re: Is 1024x 1024 true HD? |
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On Thu, 30 Dec 2004 16:47:18 -0500, charper1
<charper1.1i3kdw@satelliteguys.us> wrote:
| Quote: | There are two DVD resolutions. The first is 480i, which uses the
interlaced method to draw the images onscreen. The second is 480p, also
known as progressive scan DVD.
|
Careful: this, as written, is not correct.
There *are* two DVD resolutions, but those resolutions are 480i and
576i (NTSC and PAL, respectively). There are no 480p DVDs. The only
things that might be 480p are some (many?) DVD players that will
output a progressive-scan image from a 480i DVD, and some (many?)
display devices that can handle a 480p image. The 480p output from a
progressive-scan DVD player is processed from the 480i material on the
disc. |
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charper1
Guest
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| Posted:
Fri Dec 31, 2004 8:24 am Post subject:
Re: Is 1024x 1024 true HD? |
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This is just a copy & paste from the HD info page for NTSC and it didn't
say that it was a native resolution just a resolution in general.
--
charper1
------------------------------------------------------------------------
This message was posted via http://www.satelliteguys.us by charper1 |
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42
Guest
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| Posted:
Fri Dec 31, 2004 3:49 pm Post subject:
Re: Is 1024x 1024 true HD? |
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In article <gng9t05edjp3i7mfd8phud13gq8lk4kbgg@4ax.com>,
karyudo_usenet@yahoo.com.remove.me says...
| Quote: | On Thu, 30 Dec 2004 16:47:18 -0500, charper1
charper1.1i3kdw@satelliteguys.us> wrote:
There are two DVD resolutions. The first is 480i, which uses the
interlaced method to draw the images onscreen. The second is 480p, also
known as progressive scan DVD.
Careful: this, as written, is not correct.
There *are* two DVD resolutions, but those resolutions are 480i and
576i (NTSC and PAL, respectively). There are no 480p DVDs. The only
things that might be 480p are some (many?) DVD players that will
output a progressive-scan image from a 480i DVD, and some (many?)
display devices that can handle a 480p image. The 480p output from a
progressive-scan DVD player is processed from the 480i material on the
disc.
|
So then, what exactly is the point of a progressive scan DVD player??
My TV currently takes a 480i input from my DVD player and converts it to
720p for display. A progressive scan DVD player, you are saying, will
take the same 480i input (because that's what your saying is actually on
the DVD) convert it to 480p, and then my TV will convert that to 720p.
How is that an 'advantage'?? |
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Matthew L. Martin
Guest
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| Posted:
Fri Dec 31, 2004 7:47 pm Post subject:
Re: Is 1024x 1024 true HD? |
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42 wrote:
| Quote: | In article <gng9t05edjp3i7mfd8phud13gq8lk4kbgg@4ax.com>,
karyudo_usenet@yahoo.com.remove.me says...
There *are* two DVD resolutions, but those resolutions are 480i and
576i (NTSC and PAL, respectively). There are no 480p DVDs. The only
things that might be 480p are some (many?) DVD players that will
output a progressive-scan image from a 480i DVD, and some (many?)
display devices that can handle a 480p image. The 480p output from a
progressive-scan DVD player is processed from the 480i material on the
disc.
So then, what exactly is the point of a progressive scan DVD player??
|
To deinterlace in the digital domain.
| Quote: | My TV currently takes a 480i input from my DVD player and converts it to
720p for display. A progressive scan DVD player, you are saying, will
take the same 480i input (because that's what your saying is actually on
the DVD) convert it to 480p, and then my TV will convert that to 720p.
|
That is exactly what will happen.
| Quote: | How is that an 'advantage'??
|
It may not be. The idea is that if the DVD player does the deinterlace
in the digital domain then there will be fewer D->A, A->D conversions
and the player can take advantage of flags in the MPEG input stream.
Since your display is probably not capable of showing 480p directly, as
many CRT HDTVs can, There would propbably be fewer conversions if you
use a 480i input.
Matthew
--
Thermodynamics and/or Golf for dummies: There is a game
You can't win
You can't break even
You can't get out of the game |
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Karyudo
Guest
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| Posted:
Sat Jan 01, 2005 12:46 am Post subject:
Re: Is 1024x 1024 true HD? |
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On Fri, 31 Dec 2004 09:47:33 -0500, "Matthew L. Martin"
<nothere@notnow.never> wrote:
| Quote: | 42 wrote:
So then, what exactly is the point of a progressive scan DVD player??
To deinterlace in the digital domain.
My TV currently takes a 480i input from my DVD player and converts it to
720p for display. A progressive scan DVD player, you are saying, will
take the same 480i input (because that's what your saying is actually on
the DVD) convert it to 480p, and then my TV will convert that to 720p.
That is exactly what will happen.
How is that an 'advantage'??
It may not be. The idea is that if the DVD player does the deinterlace
in the digital domain then there will be fewer D->A, A->D conversions
and the player can take advantage of flags in the MPEG input stream.
Since your display is probably not capable of showing 480p directly, as
many CRT HDTVs can, There would propbably be fewer conversions if you
use a 480i input.
Matthew
|
Yeah, what he said. To which I'll add some stuff:
- the source for DVD movies is, of course, progressive -- it's film,
at 24fps. So 480i contains *all* the resolution of 480p when the
source is film. Instead of outputting lines 1, 3, 5, 7, [...], 2, 4,
6, 8, [...] to make up one complete frame, a progressive scan player
outputs 1, 2, 3, 4, 5, 6, 7, 8, [...]. Note that video-based sources
(TV sports, news, etc.) are *not* starting from progressive sources.
There the odd lines and even lines actually are part of two separate
moments in time, and things can (and do) move between them. So showing
that type of DVD as progressive means there needs to be some
deinterlacing, and perhaps some clever blending/bobbing/motion
compensating to make sure the picture doesn't suck.
- upscaling a 480i DVD is generally not as bad as it sounds. As I
noted, most movie DVDs start with a progressive master (1080p, say?),
and the DVD MPEG-2 spec allows for pseudo-progressive encoding,
through the use of flags that tell the decoder how to display the
almost-progressive 24fps stored on the disc as 29.97fps interlaced
images on an NTSC TV.
- From what I understand, a lot of progressive scan DVD players ignore
the MPEG-2 flags, and do field matching and decimation to go from
interlaced to progressive for movies. Seems sort of troublesome to me,
but then again it works better in those instances where the flags are
wrong or non-existent, I guess. I'm not sure this is right, but that's
what I thought I'd read. |
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Mack McKinnon
Guest
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| Posted:
Sat Jan 01, 2005 12:55 am Post subject:
Re: Is 1024x 1024 true HD? |
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We are currently using a Panasonic S97 DVD player that upconverts DVD's to
480p, 720p or 1080i, your choice. We have found the best picture on our set
to be at 720p -- which is then shown on our Sony HDTV at 788p, its native
resolution. The picture, upconverted to 720p, is a little smoother and
detailed to a point that it looks very much like HD. That is, until you cut
off the DVD player and change the input back to TV and get a real HD
signal -- then you realize how much better real HD is. Will be nice when HD
DVD gets rolling.
mack
austin
"Karyudo" <karyudo_usenet@yahoo.com.remove.me> wrote in message
news:uk9bt0pkpdusf3p5186qql5nobl12h2j0m@4ax.com...
| Quote: | On Fri, 31 Dec 2004 09:47:33 -0500, "Matthew L. Martin"
nothere@notnow.never> wrote:
42 wrote:
So then, what exactly is the point of a progressive scan DVD player??
To deinterlace in the digital domain.
My TV currently takes a 480i input from my DVD player and converts it to
720p for display. A progressive scan DVD player, you are saying, will
take the same 480i input (because that's what your saying is actually on
the DVD) convert it to 480p, and then my TV will convert that to 720p.
That is exactly what will happen.
How is that an 'advantage'??
It may not be. The idea is that if the DVD player does the deinterlace
in the digital domain then there will be fewer D->A, A->D conversions
and the player can take advantage of flags in the MPEG input stream.
Since your display is probably not capable of showing 480p directly, as
many CRT HDTVs can, There would propbably be fewer conversions if you
use a 480i input.
Matthew
Yeah, what he said. To which I'll add some stuff:
- the source for DVD movies is, of course, progressive -- it's film,
at 24fps. So 480i contains *all* the resolution of 480p when the
source is film. Instead of outputting lines 1, 3, 5, 7, [...], 2, 4,
6, 8, [...] to make up one complete frame, a progressive scan player
outputs 1, 2, 3, 4, 5, 6, 7, 8, [...]. Note that video-based sources
(TV sports, news, etc.) are *not* starting from progressive sources.
There the odd lines and even lines actually are part of two separate
moments in time, and things can (and do) move between them. So showing
that type of DVD as progressive means there needs to be some
deinterlacing, and perhaps some clever blending/bobbing/motion
compensating to make sure the picture doesn't suck.
- upscaling a 480i DVD is generally not as bad as it sounds. As I
noted, most movie DVDs start with a progressive master (1080p, say?),
and the DVD MPEG-2 spec allows for pseudo-progressive encoding,
through the use of flags that tell the decoder how to display the
almost-progressive 24fps stored on the disc as 29.97fps interlaced
images on an NTSC TV.
- From what I understand, a lot of progressive scan DVD players ignore
the MPEG-2 flags, and do field matching and decimation to go from
interlaced to progressive for movies. Seems sort of troublesome to me,
but then again it works better in those instances where the flags are
wrong or non-existent, I guess. I'm not sure this is right, but that's
what I thought I'd read. |
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Jeff Rife
Guest
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| Posted:
Sat Jan 01, 2005 1:42 am Post subject:
Re: Is 1024x 1024 true HD? |
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Karyudo (karyudo_usenet@yahoo.com.remove.me) wrote in alt.tv.tech.hdtv:
| Quote: | - the source for DVD movies is, of course, progressive -- it's film,
at 24fps. So 480i contains *all* the resolution of 480p when the
source is film.
|
This is not true.
In order to reduce interlace artifacts, filtering is done before the MPEG
compression. This loses some resolution.
--
Jeff Rife |
| http://www.nabs.net/Cartoons/Dilbert/LostNetworkPassword.gif |
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Karyudo
Guest
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| Posted:
Sat Jan 01, 2005 3:39 am Post subject:
Re: Is 1024x 1024 true HD? |
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On Fri, 31 Dec 2004 15:42:55 -0500, Jeff Rife <wevsr@nabs.net> wrote:
| Quote: | Karyudo (karyudo_usenet@yahoo.com.remove.me) wrote in alt.tv.tech.hdtv:
- the source for DVD movies is, of course, progressive -- it's film,
at 24fps. So 480i contains *all* the resolution of 480p when the
source is film.
This is not true.
In order to reduce interlace artifacts, filtering is done before the MPEG
compression. This loses some resolution.
|
I've read this from you before, but I've never seen anyone else,
anywhere say the same. I'd like to see a reference, if at all
possible.
I'd also like to read what interlace artifacts are being avoided, and
what sort of filtering is done, and how that reduces resolution.
All I know is, when I look at a DVD, IVTC'ed, in AviSynth, there are
still 720 x 480 pixels, and the luma information for each pixel is
discrete. Diagonal lines are (well, can be) both smooth and sharp.
I'm not trying to be a jerk here or anything; merely a pedant. I'm
genuinely interested to learn more. It's not everyone who goes poking
around under the hood of DVD encoding, so if there's info out there
I'm missing, I want to brush up.
However, I do think it's also a bit disingenuous to make the blanket
statement that what I've written is not true, when there really aren't
any 480p sources to compare to. |
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Jeff Rife
Guest
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| Posted:
Sat Jan 01, 2005 5:17 am Post subject:
Re: Is 1024x 1024 true HD? |
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Karyudo (karyudo_usenet@yahoo.com.remove.me) wrote in alt.tv.tech.hdtv:
| Quote: | In order to reduce interlace artifacts, filtering is done before the MPEG
compression. This loses some resolution.
I've read this from you before, but I've never seen anyone else,
anywhere say the same.
|
You must not read this group closely, then. Just one example:
http://groups-beta.google.com/group/alt.tv.tech.hdtv/msg/02edf33ff6ce1460
| Quote: | I'd like to see a reference, if at all
possible.
|
It's a requirement of *all* interlaced formats, but:
http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html
"For this reason, fine detail is often filtered from the signal before
being encoded for DVD to minimize such twitter when played back at home
on your interlaced display device."
"Often" is an understatement. "Almost always" is more correct.
See also:
http://www.dvddemystified.com/dvdfaq.html#3.8
| Quote: | I'm not trying to be a jerk here or anything; merely a pedant. I'm
genuinely interested to learn more.
|
OK, so don't take this the wrong way either, but a *very* quick Google
search revealed the above references (and there are other postings in this
very group), so I don't think you've been trying very hard on this one
point.
| Quote: | However, I do think it's also a bit disingenuous to make the blanket
statement that what I've written is not true, when there really aren't
any 480p sources to compare to.
|
There actually are. There was one major DVD (I'm sorry that the name
escapes me now) where they forgot to do the filtering and just encoded the
material. All accounts said it looked pretty bad on interlaced displays
but awesome with a progressive scan player and display.
--
Jeff Rife | "What kind of universe is this where a man can't
| love his fake wife's mother's best friend?"
|
| -- Ned Dorsey, "Ned and Stacey" |
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John S. Dyson
Guest
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| Posted:
Sat Jan 01, 2005 5:32 am Post subject:
Re: Is 1024x 1024 true HD? |
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In article <MPG.1c3fb62040f8c0dd989a36@news.nabs.net>,
Jeff Rife <wevsr@nabs.net> writes:
| Quote: | Karyudo (karyudo_usenet@yahoo.com.remove.me) wrote in alt.tv.tech.hdtv:
In order to reduce interlace artifacts, filtering is done before the MPEG
compression. This loses some resolution.
I've read this from you before, but I've never seen anyone else,
anywhere say the same.
You must not read this group closely, then. Just one example:
I agree with Jeff also. Twitter can be obnoxious unless it is |
removed. Even if there isn't twitter, anti aliasing is important,
otherwise the video can be ugly. (Stairsteppy, even moire is possible.)
| Quote: |
"For this reason, fine detail is often filtered from the signal before
being encoded for DVD to minimize such twitter when played back at home
on your interlaced display device."
"Often" is an understatement. "Almost always" is more correct.
Intelligent anti-aliasing can be used (dynamic rolloff of vertical |
detail.) This can keep the loss of fine vertical detail minimzed,
but also mitigate the worst of the twitter.
| Quote: |
I'm not trying to be a jerk here or anything; merely a pedant. I'm
genuinely interested to learn more.
OK, so don't take this the wrong way either, but a *very* quick Google
search revealed the above references (and there are other postings in this
very group), so I don't think you've been trying very hard on this one
point.
It is important to understand the effects of aliasing in video, even |
if the mathematical details aren't well understood. (Of course,
DSP knowledgeable people can easily understand the effects of
aliasing.)
| Quote: |
However, I do think it's also a bit disingenuous to make the blanket
statement that what I've written is not true, when there really aren't
any 480p sources to compare to.
There actually are. There was one major DVD (I'm sorry that the name
escapes me now) where they forgot to do the filtering and just encoded the
material. All accounts said it looked pretty bad on interlaced displays
but awesome with a progressive scan player and display.
Even in that case, I'd suspect that they did an adequate job of anti-aliasing |
based upon the 720Hx480V sampling structure. Without anti-aliasing, even
non-interlaced video can look ugly... (Many video sampling devices do
automatically handle some modicum of anti-aliasing.) In a TV camera,
they actually can use a special optical filter BEFORE the CCD, so that
the spatial filtering happens before the sampling of the CCD imager. In
higher end TV cameras, they use a less drastic optical filter, and then
the CCD array has a finer (more pixel) structure like perhaps 860Hx960V,
and then the output of the CCD is further digitally filtered down to
720Hx480V. This has the effect of providing a sharper vertical/horizontal
filter, and the normal optical filters for 720Hx480V tend to be sloppier
than can be done by the digital filtering.
Of course, like usual, I drifted in my discussion about anti-alias filtering
for digital video.
Bottom line: normally you really do want to rolloff the video before
sampling it. In some cases, this filtering can happen in the optical domain.
Without proper anti-aliasing, video image quality can look very very rough
and ugly. With proper anti-aliasing, the video can provide nice, fine detail,
yet also avoid twitter and avoid excessive stairstepping. Each of twitter,
stairstepping, Moire, and a harsh-edgy look can at least partially result
from aliasing... (Also, an overly sharp rolloff can make the edges look
harsh also.)
Another thing: MPEG encoding (probable current distribution technology)
and/or NTSC composite encoding (legacy distribution technology) each don't
necessarily like to see lots of excess high frequency detail, and especially
MPEG doesn't like to see lots of random high frequency noise... In the
case of NTSC, it doesn't like to see lots of excess high frequency vertical
detail, because it makes distingushing between chroma and luma more
problematical... (Of course, appropriate prefiltering helps to mitigate
the comb filter decode problem.)
John |
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