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(Aaron Brezenski) wrote in
news:brauuv$69r$:

> Sure, it's possible. It's just not done: you buy a 4:3 monitor which
> is advertised as 1080i, you're not getting one whose 16:9 section is
> 1080i but with extra rez for 4:3, you're getting one whose total line
> count is 1080i and less for 16:9. The CE companies aren't giving away
> free extra rez to the 4:3 TV owner.

Hm. I may be misunderstanding monitor tech, but I didn't think you lost
scan lines by squeezing the picture. I thought the effect was similar to
adjusting the image height on a computer monitor; same number of scan lines
by the electron guns, just aiming at a tighter vertical space on the crt
face. I could see the dot pitch on the mask/grille affecting this, I
guess, but it wouldn't be a steep loss, would it?

Geo
--
George Mealer | geo*at*snarksoft*dot*com

"George Mealer" <> wrote in message
news:Xns944EBC3AC8A19geosnarksoftcom@208.201.224.1 54...
> (Aaron Brezenski) wrote in
> news:brauuv$69r$:

> Sure, it's possible. It's just not done: you buy a 4:3 monitor which
> is advertised as 1080i, you're not getting one whose 16:9 section is
> 1080i but with extra rez for 4:3, you're getting one whose total line
> count is 1080i and less for 16:9. The CE companies aren't giving away
> free extra rez to the 4:3 TV owner.

<<Hm. I may be misunderstanding monitor tech, but I didn't think you
lost scan lines by squeezing the picture. I thought the effect was
similar to adjusting the image height on a computer monitor; same number
of scan lines by the electron guns, just aiming at a tighter vertical
space on the crt face. I could see the dot pitch on the mask/grille
affecting this, I guess, but it wouldn't be a steep loss, would it?
Geo>>


It appears to me that there is no loss of scan lines, but in 4:3 high
definition sets, there could be too few pixels available to display all
of the picture information in a compressed image. Here is a pixel
(dot-pitch) related argument which I once made in regard to compressing
anamorphic DVD images on standard CRT screens. The concept being
presented here may not be fully applicable to standard CRTs, but it may
be fully applicable to high definition sets.

This argument assumes the following criteria is correct:

Dot Pitch
"The dot pitch of a monitor refers to the size of the pixels on the
screen. The pixels are the tiny little dots of color used to make up the
entire picture. The lower the dot pitch number the smaller the actual
dots are. This also means there are more dots on the smaller dot pitch
monitors. This affects the resolution of the image on the screen
dramatically when you compare a .29 dot pitch monitor to one with a .22
dot pitch on the same size screen. The .22 monitor will have more dots
on the screen and a clearer picture."

http://www.epinions.com/cmd-review-8...39455FB8-prod2

As long as the dot pitch, or pixel size, is small enough to meet or
exceed the resolution of the vertically compressed DVD source, there
will be no problem. This "too few pixels" explanation may apply only to
fixed-panel digital displays, such as DLP, LCD, or plasma. It may not
fully apply to standard-resolution CRT sets. Many of these digital
displays already have a fixed-panel resolution inherently higher than
DVD, but these assumptions may not be applicable to high definition
4:3 CRTs.

By vertically-compressing an anamorphic image by 25%, geometric
integrity is restored without taking any scan lines from the visible
image. The resulting increase in resolution is usually said to be around
33%. However, this claim may not always be correct.

Because the compressed anamorphic image is being squeezed into a smaller
slice of the 4:3 TV screen, the actual number of pixels used to display
the visible image is decreased, resulting in the availability of fewer
pixels to display the compressed image. Fewer pixels result in less
resolution and therefore, the assumption that anamorphic DVDs have a
33% increase in image detail may become invalid on some TVs. The
following formula suggests that the actual increase in image detail
present in compressed anamorphic images may drop to as little as 25%.

My premise is that the original anamorphic image has a value of 100% and
then, after it is squeezed down to 75% of its original size, it is being
displayed by 25% fewer pixels. Correspondingly, the original theoretical
33% increase in resolution -- which may not be supported by the
remaining available screen pixels -- could be reduced to as little as
75% of its original value. Depending upon the pixel count, the actual
increase in picture resolution could be as little as 25% and as much
33%.

In the case of 4:3 high definition sets, the following formula could be
accurate:

33% (compression) x 75% (area of compressed image) = 25% actual
increased picture resolution.

Here is an explanation of how the above formula was obtained:

For every 4 scan lines present in an anamorphic widescreen image, there
are only 3 scan lines in the same non-anamorphic widescreen image. In
order to restore geometric integrity to vertically-stretched anamorphic
images, the down-conversion process of a DVD player removes 1 out of
every 4 scan lines from an anamorphic picture and then uses the hijacked
scan lines to create the black lines above and below the trashed
down-converted image. On the other hand, a vertically compressed image
does not have its black bars created from any recycled scan lines that
previously contained picture information.

It is now possible to assign values to the two resolutions in order to
see how the math works:

Anamorphic = 4

Non-anamorphic = 3

There is 1 scan line separating anamorphic DVDs from non-anamorphic
DVDs. It is the relationship of this single scan line to anamorphic and
non-anamorphic images that establishes the percentage of difference
between them.

An anamorphic image (with an assigned value of 4) has 33% more picture
detail than a non-anamorphic image (with an assigned value of 3). This
means that unprocessed anamorphic DVDs have 33% more resolution than non
anamorphic and down-converted anamorphic DVDs.

A non-anamorphic image (with an assigned value of 3) has 25% less
picture detail than an anamorphic image (with an assigned value of 4).
This would mean that non-anamorphic and down-converted anamorphic DVDs
have 25% less resolution than unprocessed anamorphic DVDs.

However, a television must have adequate pixels in order to fully
display the maximum picture detail available. It appears that 4:3 high
definition sets may lack this ability.

In article <Xns944EBC3AC8A19geosnarksoftcom@208.201.224.154 >,
George Mealer <> wrote:
> (Aaron Brezenski) wrote in
>news:brauuv$69r$:
>
>> Sure, it's possible. It's just not done: you buy a 4:3 monitor which
>> is advertised as 1080i, you're not getting one whose 16:9 section is
>> 1080i but with extra rez for 4:3, you're getting one whose total line
>> count is 1080i and less for 16:9. The CE companies aren't giving away
>> free extra rez to the 4:3 TV owner.
>
>Hm. I may be misunderstanding monitor tech, but I didn't think you lost
>scan lines by squeezing the picture.

You're right.

> I thought the effect was similar to
>adjusting the image height on a computer monitor; same number of scan lines
>by the electron guns, just aiming at a tighter vertical space on the crt
>face. I could see the dot pitch on the mask/grille affecting this, I
>guess, but it wouldn't be a steep loss, would it?

Scot's post illustrates it far better than I ever could. You're not "losing"
scan lines, but by compressing to a tighter space than usual, the actual resolving
power of the screen (and probably mask/grille to some extent) can come
into play. The scan lines are all *there*, but they're overlapping each other
and your ability to resolve pixels on adjacent lines is reduced.


--
Aaron Brezenski
Not speaking for my employer in any way.

>But you're going to have bars either way, if you enjoy old pre-HD
>shows. Bars on the side, bars on the top... makes no difference to me,
>to be honest.
>
>-

an alcoholic who I know would just love that.

bars everywhere.

I couldn't resist.

(Adam Smith) wrote in message news:< om>...
> What do the new 4:3 hdtvs

4:3 HDTVS are not HDTVs. HDTV is a 16:9 ratio. If the image of a
broadcast HD show does not fill the screen(without any zooming effect
which would crop the image or squeezing effect which would create a
smaller viewing area) then it's not an HDTV.

Smuag69

Invid Fan <> wrote in message news:<111220031701429673%>...
> In article <>,
> LASERandDVDfan <> wrote:
>
> > >It may be purely subjective, but could you state some of the reasons
> > >why 4:3 hdtv is inadequate?
> > >
> >
> > When HDTV ultimately replaces NTSC broadcasts, pretty much all HDTV broadcasts
> > will be done in 16:9. This means that, if you have a 4:3 set, you are going
> > to
> > get black bars on the top and bottom parts of the screen with all broadcasts.
> > 16:9 is wider than 4:3. - Reinhart
>
> But you're going to have bars either way, if you enjoy old pre-HD
> shows. Bars on the side, bars on the top... makes no difference to me,
> to be honest.

But for HDTV content- things that are broadcast in 16x9- it really
does matter whether you have a 16x9 TV or not.

Smaug69

"Aaron Brezenski" <> wrote in message
news:brahct$vpi$...
> In article < >,
In article < >,
Adam Smith <> wrote:
>It may be purely subjective, but could you state some of the reasons
>why 4:3 hdtv is inadequate?
>
>Thanks.
>
>Adam Smith

<<You'll lose resolution on true-HDTV presentations (16x9), as the 4:3
TV will letterbox them, or do an anamorphic squeeze to a size which
likely exceeds the true capability of the set to resolve 1080i.>>

<<On the other hand, if all you're watching are 4:3 presentations, or
DVDs, you'll "lose" nothing, although with comparable upconversion
circuitry you'd be better off with a 16:9 for watching widescreen
DVDs.>>

<<I don't think anyone is broadcasting 4:3 1080i, but I could be
wrong.>>


I have recently been experimenting with a new phenomenon: Anamorphic 4:3
material. While this may seem like a contradiction in terms, it is not
without precedent:

The _Boogie Nights_ supplementary disk has a couple of anamorphic images
with a 4:3 aspect ratio. The only other time that I ever saw this was on
the theatrical trailer from Jailhouse rock. This can be found on the
_Boogie Nights_ disk containing the supplements. The deleted scenes 3
and 6 are anamorphic, but they are in a 4:3 aspect ratio with black bars
on the top and bottom as well as the sides.

I recently bought a Panasonic DVD-S55 player, which has the following
picture size adjustments:

4:3 Aspect: Select how to show images made for 4:3 aspect
screens on a 16:9 aspect television.

Normal: Laterally stretches images made for a 4:3 screen.

Auto: Expands suitable 4:3 letterbox images to fill more of
the screen. Other images appear in full in the center of the
screen.

Shrink: Images appear in the center of the screen.

Zoom: Expands all images to fill the screen.

In order to view anamorphic 4:3 DVD images on a conventional TV, you
must have a TV which can do the vertical squeeze (an anamrophic mode)
and a DVD player which has a "shrink" mode. What the shrink mode of the
DVD player does is to squeeze the sides of a non-anamorphic 4:3 DVD
image by 25%. This creates black bars on the sides of the image.
Then, when the TV's vertical compression is also used, the image is
compressed into a geometrically-correct 4:3 shape. True, the shrunken
image is now 25% smaller than a standard 4:3 image, but the picture
clarity, color and overall detail are vastly improved. Best of all, the
horizontal scan lines have nearly disappeared.

Prior to using the "shrink" mode on 4:3 DVD images, only anamorphic DVDs
could benefit from vertical compression. (The player seems to be able to
differentiate between non-anamorphic material and anamorphic material
because anamorphic menus and movies, are never shrunk.)

Traditional 4:3 DVD images come in two varieties: Standard academy ratio
4:3 and various sizes of widescreen letterboxed images. All of these
non-anamorphic images benefit from player shrinking and vertical
compression. On non-anamorphic widescreen material, the zoom mode may be
used to enlarge the image slightly, without seriously affecting the
picture quality. (Zooming on compressed 4:3 material is not an option
because the top and bottom of the image becomes more and more cut off as
the size increases. On widescreen material, the top and bottom sections
of the image are black bars, so there is no picture loss, but of course,
the image becomes less and less detailed as it is enlarged.)

"Scot Gardner" <> wrote in news:20031212115259.429
$:

> However, a television must have adequate pixels in order to fully
> display the maximum picture detail available. It appears that 4:3 high
> definition sets may lack this ability.

OK, so to distill your argument, the screen itself may not have the dot
pitch necessary to support the tighter scanlines. I can go with that.
Without knowing the dot pitch of a particular CRT, though, all you can say
for sure is that it -might- not be as clear. It's possible that there are
"dots to spare", at least for 480p. Clearly, a good audition of the set
would be in order.

Geo
--
George Mealer | geo*at*snarksoft*dot*com