1080I / 720P

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What is the difference between 1080i and 720P ?

Thank you

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drs_retired wrote:
> What is the difference between 1080i and 720P ?
>
> Thank you
>
>


1080i: 1080 horizontal lines of resolution, with every other line
drawn each frame (interlaced)

720p: 720 horizontal lines of resolution, with all 720 drawn each
frame (progressive scan).

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drs_retired wrote:
> What is the difference between 1080i and 720P ?
>
> Thank you

360 and a few letters.

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In article <MPG.1b1ecd4293216162989705@news.gwtc.net>,
Ron Malvern <rmlvrn@nospam.com> writes:
> In article <5Y6tc.12403$be.2907@newsread2.news.pas.earthlink.net>,
> drs_retired@earthlink.net says...
>> What is the difference between 1080i and 720P ?
>
> Both are high definition formats. With 1080i, the "i" stands for
> interlace. With 720p, the "p" stands for progressive scan.
>
> They have roughly equivalent resolution, with 1080i having the edge in
> horizontal resolution, 720p having the edge in vertical and color
> resolution.
>
Per the corrected 'Final Technical Report" dated Oct 31, 1995 in the ATSC
archives, the statement about 720p having the edge in vertical and
color resolution isn't quite accurate. For static information (which
is what most of us perceives as viewable detail), both 1080i
and 720p have approx the same vertical chroma and vertical luma
resolution. 1080i has higher horizontal and diagonal, chroma and
luma resolution than 720p.

For dynamic vertical resolution, the 720p does have the edge, but that
has seldom been denied. For almost all perceivable STATIC resolution
figures (including color), 1080i does provide more detail. Even
in the dynamic situation, 1080i has more horizontal detail (both
chroma and luma.)

John

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In article <c93c23$2fnm$1@news.iquest.net>, toor@iquest.net says...
> In article <MPG.1b1ecd4293216162989705@news.gwtc.net>,
> Ron Malvern <rmlvrn@nospam.com> writes:
> > They have roughly equivalent resolution, with 1080i having the edge in
> > horizontal resolution, 720p having the edge in vertical and color
> > resolution.
> >
> Per the corrected 'Final Technical Report" dated Oct 31, 1995 in the ATSC
> archives, the statement about 720p having the edge in vertical and
> color resolution isn't quite accurate. For static information (which
> is what most of us perceives as viewable detail), both 1080i
> and 720p have approx the same vertical chroma and vertical luma
> resolution. 1080i has higher horizontal and diagonal, chroma and
> luma resolution than 720p.

That's a blanket statement that simply isn't true. In the Final
Technical Report from the ATSC you mentioned above, look at table 2.3.

In vertical static chroma resolution, 720p rates 180, 1080i rates only
140.

In vertical dynamic luminance resolution, 720p rates 210, 1080i rates
200.

In horizontal dynamic chroma (color) resolution, 720 rates 170, 1080i
rates 135.

In vertical dynamic chroma (color) resolution, 720p rates 160, 1080i
rates only 100.

In diagonal dynamic chroma (color) resolution, 720p rates 183, 1080i
rates only 135.

> For dynamic vertical resolution, the 720p does have the edge, but that
> has seldom been denied. For almost all perceivable STATIC resolution
> figures (including color), 1080i does provide more detail.

But since we're talking about moving pictures here, dynamic resolution
with moving images will always be more important.
In addition, of course, the progressive formats take up less bandwidth,
meaning cleaner and more artifact-free transmission.

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In article <q8eab0lhb4pqekdt9b06dbhlp10upucns1@4ax.com>,
Karyudo <karyudo_usenet@yahoo.com.remove.me> writes:
> On Wed, 26 May 2004 19:40:00 -0400, "David G."
> <david_please_dont_email_me@i_hate_spam.com> wrote:
>
>>Some high-tech sets are in production that will display 1080p. I doubt
>>the industry will adopt this as a transmission standard as it will
>>consume more bandwidth.
>
> If you're talking 1080/60p, then the industry *can't* adopt this,
> because IIRC it's not even part of the ATSC standard. Or, if it is in
> the standard, it still isn't part of the broadcast standard, because
> it won't fit into the current bandwidth alotted to TV channels.
>
> If you mean 1080/24p, then the industry *should* adopt it (at least
> for film-sourced material) because it reduces bandwidth.
>
If you read the ATSC spec, you'll notice that the 1080i30 signal can
be sent to take advantage of the redundancy of the 1080/24p original
source. So, you can get some advantage from the redundancy in the
24p originated material, yet transmit the signal in the 1080i30 format

John

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In article <MPG.1b1f0bca66244a57989707@news.gwtc.net>,
Ron Malvern <rmlvrn@nospam.com> writes:
> In article <c93jum$2i5b$1@news.iquest.net>, John Dyson toor@iquest.net
> says...
>
>> In article <MPG.1b1ef140da52bf36989706@news.gwtc.net>,
>> > In vertical static chroma resolution, 720p rates 180, 1080i rates only
>> > 140.
>
>> That is a slight difference, when comparing the following:
>> 720p diagonal is 230 vs. 1080i diagonal is 260.
>
> In what? Chroma? Luma? You don't say. Be specific, John. For an
> engineer, you are incredibly sloppy with details.
>
The context was obvious if you also look at the table. I assumed that
you could maintain context... Of course, maybe the large number
of discrete data items can cause confusion. (Alot like moving
objects on the screen :-).) Perhaps all of the details within the
field of view might be confusing to you?

Remember also: if you maintain all detail in moving objects (allow temporal
aliasing), then movement doesn't even look natural. Film productions are
generally recorded with averaging over the entire sampling interval. There
is a natural motion smear to 'natural' perception. If you allow temporal
alasing, the movement tends to be less natural (and wierd strobing
effects become more troublesome.)

So, on filmed material, moving items tend to have less 'detail' because
of averaging over the exposure time. Some video cameras can set the
'exposure time' to be different than the frame rate -- but that is
more of a utility for special purposes (e.g. sports freeze frame or
flicker reduction or other purposes.)

>
>
>> Also, in the 'target spec' the difference between 1080i and 720p is
>> reversed.
>
> So?! The target spec doesn't matter.
>
Yes it does -- refer to the 'Note 1' that describes their concept
of measurement error (or equivalent.)

>
> The test spec is what matters.
>
And the differences were in the order of measurement error.

>
> Any
> fool can say he want x and y performance from a given piece of equipment.
>
You are being abusive. A fool with an agenda would ignore the concept of
measurement error...

>
> We're not talking statistics here, John. We're talking test results.
>
All tests have measurment error, Ron. The individuals who collected
the data apparently believed that there was error in their technique
or in their measurements.

>
> But if you want to make a big deal of that, then the entire ATSC Final
> Technical Report is meaningless
>
Reducing the argument to the absurd. Refer to the differences that
were deemed within measurement error. Note that the 'error' in this
context would also include measurement technique issues.

Remember: the significant differences that were outside of
reasonable 'measurement error' showed that 1080i provided more
detail.

>
>> > But since we're talking about moving pictures here, dynamic resolution
>> > with moving images will always be more important.
>
>> Nope -- most detail isn't moving, or MPEG wouldn't work!!!
>
> But the part of the image at the center of attention, faces, bodies, etc.
> are moving all the time.
>
However, the human visual system cannot deal with very much moving detail.
Also(side issue), moving image material that has been properly
exposed (to minimize temporal aliasing) will naturally have smear
due to movement.

Using your argument, you wouldn't care to keep a book still while
reading it -- because you could obviously track the vibrating book!!!
Not!!! (Hint, I have a movement disorder, and can attest to the
difficulty of tracking a moving page of text -- a prototypical
high detail image.)

Mostly, you'll easily see the gross details when something is moving.
You won't see all of the small little precise details (think about a
moving page of written text. Your eyes won't process the detail as well
as if it was still.)

>
>> Take a look
>> at the typical TV show... Detail isn't typically moving!!! If your
>> claim is true, the MPEG wouldn't work. Most detail in video and
>> movies is unchanging...
>
> Gee John, you mean all that stuff on the screen in the movie theatres and
> on television was just standing still all these years!
>
Most of the detail isn't moving, or MPEG-type interframe
compression wouldn't work. It appears that you are using semantics
to justify your incorrect argument...

Again, static detail rendition is more important for the perception
of sharpness. You CAN track moving objects, but your detail perception
is necessarily reduced (otherwise, you wouldn't need to keep books
still while reading them!!!)


John

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In article <MPG.1b1f13e39eea8545989709@news.gwtc.net>,
Ron Malvern <rmlvrn@nospam.com> writes:
> In article <c93k1c$2i5b$2@news.iquest.net>, toor@iquest.net says...
>
>> If you read the ATSC spec, you'll notice that the 1080i30 signal can
>> be sent to take advantage of the redundancy of the 1080/24p original
>> source. So, you can get some advantage from the redundancy in the
>> 24p originated material, yet transmit the signal in the 1080i30 format
>
> First of all, 1080i is not referred to as 1080i30. It's 1080/60i.
>
I have seen it both ways. 1080i30 would be 30 frames per second.
This would be equivalent to 720p60 as 60 frames per second. Likewise,
I have also seen it with the inconsistent approach like you suggest,
where sometimes it is 'frames per second' and sometimes it
is 'fields per second.' I prefer using the same units all of
the time, where the number after the i/p is 'frames per second.'

>
> Secondly it's commonly acknowedged that 1080/24p takes less bandwidth
> than does 1080i because of the greater compression efficiency of
> progressive scan.
>
The improvement between 1080p24 and 1080i30 isn't as great as one
might guess, because of the 'repeated' information that is sent
as 'repeats.' So, it doesn't really need to send 30 full frames
per second in the case of 1080i. The progressive thing is another
issue, but NOT THE ONLY ONE :-).

Maybe you didn't realize that?

John

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In article <c93pfp$2jil$1@news.iquest.net>, toor@iquest.net says...
> In article <MPG.1b1f13e39eea8545989709@news.gwtc.net>,

> I have seen it both ways. 1080i30 would be 30 frames per second.
> This would be equivalent to 720p60 as 60 frames per second. Likewise,
> I have also seen it with the inconsistent approach like you suggest,
> where sometimes it is 'frames per second' and sometimes it
> is 'fields per second.' I prefer using the same units all of
> the time, where the number after the i/p is 'frames per second.'

The number doesn't refer to frames per second. It refers to Herz, or
cycles per second. And in this case, passes of the raster.
Secondly "frames" don't exist in an interlaced system. All you have
are "fields" that can't combine to make a frame, in spite of what you
were told in high school. The fields can't match to make a frame since
the fields are always exposed at different moments in time. This is why
taking still "frames" from interlaced material seldom produces good
results. This is also the main reason de-interlacers don't work well at
all.

> > Secondly it's commonly acknowedged that 1080/24p takes less bandwidth
> > than does 1080i because of the greater compression efficiency of
> > progressive scan.
> >
> The improvement between 1080p24 and 1080i30 isn't as great as one
> might guess, because of the 'repeated' information that is sent
> as 'repeats.' So, it doesn't really need to send 30 full frames
> per second in the case of 1080i. The progressive thing is another
> issue, but NOT THE ONLY ONE :-).
> Maybe you didn't realize that?

Obviously you didn't realize that I was talking about compression
efficiencies produced by progressive scan. It is not "another" issue.
It is the main issue.

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Ron Malvern wrote:
> In article <c93pfp$2jil$1@news.iquest.net>, toor@iquest.net says...
>> In article <MPG.1b1f13e39eea8545989709@news.gwtc.net>,
>
>> I have seen it both ways. 1080i30 would be 30 frames per second.
>> This would be equivalent to 720p60 as 60 frames per second.
>> Likewise, I have also seen it with the inconsistent approach like
>> you suggest, where sometimes it is 'frames per second' and sometimes
>> it
>> is 'fields per second.' I prefer using the same units all of
>> the time, where the number after the i/p is 'frames per second.'
>
> The number doesn't refer to frames per second. It refers to Herz,
> or cycles per second. And in this case, passes of the raster.
> Secondly "frames" don't exist in an interlaced system. All you
> have are "fields" that can't combine to make a frame, in spite of
> what you were told in high school. The fields can't match to make a
> frame since the fields are always exposed at different moments in
> time. This is why taking still "frames" from interlaced material
> seldom produces good results. This is also the main reason
> de-interlacers don't work well at all.
>

Many deinterlacers work well in movie mode. It's video encoded
interlaced streams that are difficult to deinterlace. But companies such
as Faroujda with their DCDi have created some great deinterlacers for
video based material. I wonder what kind of processing is required
though to deinterlace a 1080i video stream.

--
David G.

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In article <6f2bb0p629dluk5ih2qkhkvmi2gu36cf10@4ax.com>,
karyudo_usenet@yahoo.com.remove.me says...
> On Wed, 26 May 2004 23:24:14 -0600, Ron Malvern <rmlvrn@nospam.com>
> wrote:
>
> >All you have
> >are "fields" that can't combine to make a frame, in spite of what you
> >were told in high school.
>
> False for film-based material.

Well, gee, let's all go back to shooting film. Since film is essentially
a progressive format, you're making my point.


> All of these points are false when you're talking about material that
> may be interlaced, but originated as film. Which is most TV dramas, a
> number of sitcoms, and of course almost all movies.

It doesn't say much for your interlaced system if you have to use an
essentially progressive scan camera-original such as film to make
your interlace work properly.
Film has been saving the ass of interlace for years.


> John is correct; you are less so. You're right in saying that 24p is
> more efficient, but John is not disputing that -- he's saying that the
> improvement in efficiency over correctly-broadcast 30i is minimal,
> which is true.

Progressive scan material compresses up to twenty percent more
efficiently, depending on the nature of the material. You can call that
minimal if you like. Nobody with any sense would. And by the way, 1080i
is 60i not 30i.

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"Ron Malvern" <rmlvrn@nospam.com> wrote in message
news:MPG.1b1f295911a5185098970b@news.gwtc.net...
> In article <c93pfp$2jil$1@news.iquest.net>, toor@iquest.net says...
> > In article <MPG.1b1f13e39eea8545989709@news.gwtc.net>,
>
> > I have seen it both ways. 1080i30 would be 30 frames per second.
> > This would be equivalent to 720p60 as 60 frames per second. Likewise,
> > I have also seen it with the inconsistent approach like you suggest,
> > where sometimes it is 'frames per second' and sometimes it
> > is 'fields per second.' I prefer using the same units all of
> > the time, where the number after the i/p is 'frames per second.'
>
> The number doesn't refer to frames per second. It refers to Herz, or
> cycles per second. And in this case, passes of the raster.
> Secondly "frames" don't exist in an interlaced system. All you have
> are "fields" that can't combine to make a frame, in spite of what you
> were told in high school. The fields can't match to make a frame since
> the fields are always exposed at different moments in time.

This is simply your re-interpretation of terminology. The fact is that two
fields of interlaced material has always been considered a frame and that
usage of terminology is ubiquitous. Just because it violates what you
consider to be the priniciple that all scans lines must be sampled at the
same point in time, doesn't mean that calling two fields a frame is wrong.
While your understanding of what fields are is correct, your use of
terminology is not.

Archived from groups: alt.tv.tech.hdtv (More info?)

Randy Sweeney (rsweeney1@comcast.net) wrote in alt.tv.tech.hdtv:
> 1080 i = 1920x1080 pixels interlaced - interlaced means that every 1/30 of a
> second, 540 of the pixels are displayed (the odd pixels) and the next 1/30
> of a second the next 540 pixels are displayed (the even ones) - interlaced
> like interdigitating the fingers of each hand

That's wrong.

The ATSC mode is 1920x1080/60i, so every 1/60th of a second, 540 lines are
displayed, and then 1/60th of a second later, the other 540 lines are
displayed.

Yes, the display of each field lasts 1/30th of a second, but you get new
information every 1/60th of a second.

--
Jeff Rife | "Hey, dogs guard.
SPAM bait: | Cats watch...and judge."
AskDOJ@usdoj.gov |
uce@ftc.gov | -- Salem the Cat

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In article <CaJtc.28758$zO3.6131@newsread2.news.atl.earthlink.net>,
"FLY135" <fly_135(@ hot not not)notmail.com> says...
>
> "Ron Malvern" <rmlvrn@nospam.com> wrote in message
> news:MPG.1b1f13e39eea8545989709@news.gwtc.net...
> > First of all, 1080i is not referred to as 1080i30. It's 1080/60i.
>
> Says who?

Says the ATSC.

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In article <m4Ntc.28949$zO3.21044@newsread2.news.atl.earthlink.net>,
"FLY135" <fly_135(@ hot not not)notmail.com> writes:
>
> "Ron Malvern" <rmlvrn@nospam.com> wrote in message
> news:MPG.1b21494f2397eb8098970d@news.gwtc.net...
>> In article <CaJtc.28758$zO3.6131@newsread2.news.atl.earthlink.net>,
>> "FLY135" <fly_135(@ hot not not)notmail.com> says...
>> >
>> > "Ron Malvern" <rmlvrn@nospam.com> wrote in message
>> > news:MPG.1b1f13e39eea8545989709@news.gwtc.net...
>> > > First of all, 1080i is not referred to as 1080i30. It's 1080/60i.
>> >
>> > Says who?
>>
>> Says the ATSC.
>
> I didn't say that term 60i was incorrect. I'm saying that it is used both
> ways. Although just 1080i is the most common.
>
I just did a quick scan of the spec, and didn't see the 'official
specification' of the 1080i30 (normal HDTV) vs. 1080i60 as being
normal HDTV. It makes much more sense to use the same units for
720p60 and 1080i30 as meaning that each pixel location is updated
at the 60Hz rate in the 720p example, and at the 30Hz rate in the
1080i example.

However, I have definitely seen both kinds of designation, and it
is usually pretty clear when someone has mixed the field and frame
update rates like 1080i60 vs. 720p60. If this was formally defined,
it makes MUCH MORE sense to use the same units --

<scanning-structure> [p | i ] <full-picture-update>

Frankly, I wouldn't see a need to 'correct' someone who used
consistent units, just as I wouldn't see a need to 'correct'
someone who used inconsistent units. In the scheme of things,
this designation isn't all that important, and cannot understand
the importance of strongly asserting a 'correction' that
only changes the kind of error :-).

As an engineer, I am loathe to mix units, and is why I personally
prefer the more consistent 1080i30 (for 30 frames per second) or
720p60 (for 60 frames per second.)

John

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <%t0uc.3676$Yd3.3467@newsread3.news.atl.earthlink.net>,
"FLY135" <FLY_135(@hot not not)notmail.com> writes:
>
> "John S. Dyson" <toor@iquest.net> wrote in message
> news:c98lrd$1021$1@news.iquest.net...
>> In article <m4Ntc.28949$zO3.21044@newsread2.news.atl.earthlink.net>,
>> "FLY135" <fly_135(@ hot not not)notmail.com> writes:
>> >
>> > "Ron Malvern" <rmlvrn@nospam.com> wrote in message
>> > news:MPG.1b21494f2397eb8098970d@news.gwtc.net...
>> >> In article <CaJtc.28758$zO3.6131@newsread2.news.atl.earthlink.net>,
>> >> "FLY135" <fly_135(@ hot not not)notmail.com> says...
>> >> >
>> >> > "Ron Malvern" <rmlvrn@nospam.com> wrote in message
>> >> > news:MPG.1b1f13e39eea8545989709@news.gwtc.net...
>> >> > > First of all, 1080i is not referred to as 1080i30. It's 1080/60i.
>> >> >
>> >> > Says who?
>> >>
>> >> Says the ATSC.
>> >
>> > I didn't say that term 60i was incorrect. I'm saying that it is used
> both
>> > ways. Although just 1080i is the most common.
>> >
>> I just did a quick scan of the spec, and didn't see the 'official
>> specification' of the 1080i30 (normal HDTV) vs. 1080i60 as being
>> normal HDTV. It makes much more sense to use the same units for
>> 720p60 and 1080i30 as meaning that each pixel location is updated
>> at the 60Hz rate in the 720p example, and at the 30Hz rate in the
>> 1080i example.
>
> ATSC does use vertical scan frequency (i.e 60Hz) when describing the format.
> It's not any kind of an official declaration of terminology to the extent it
> could be cited to prove others wrong.
>
>> Frankly, I wouldn't see a need to 'correct' someone who used
>> consistent units, just as I wouldn't see a need to 'correct'
>> someone who used inconsistent units.
>
> Well this the important thing, especially in light of his insistance that
> two fields of interlaced material don't make a frame. Which is clearly
> incorrect.
>
>> As an engineer, I am loathe to mix units, and is why I personally
>> prefer the more consistent 1080i30 (for 30 frames per second) or
>> 720p60 (for 60 frames per second.)
>
> Yes but both 1080i and 720p are 60Hz. So it's a matter of what units you
> are using. Vert scan or frames. Either way it's obvious as to what is
> being refered to just by saying 1080i and 720p.
>
One problem with 1080i or 720p is that 720p might be 720p30 or 720p60.
There are actually some consumer camcorders that use 720p30.

John

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"John S. Dyson" <toor@iquest.net> wrote in message
news:c98lrd$1021$1@news.iquest.net...

> As an engineer, I am loathe to mix units, and is why I personally
> prefer the more consistent 1080i30 (for 30 frames per second) or
> 720p60 (for 60 frames per second.)

Sorry John, but, regardless of how commonly it may be used, that is an
extremely inconsistent usage and to me quite confusing. To me, that means
that each field is updated 30 times per second, giving an overall framerate
equivalent of only 15fps (and intolerable flickering, unless each field line
is then displayed twice as it would be in a 30p arrangement).

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <174uc.13918$Fo4.195490@typhoon.sonic.net>,
"Matthew Vaughan" <matt-no-spam-109@NOSPAM.hotmail.com> writes:
> "John S. Dyson" <toor@iquest.net> wrote in message
> news:c9ahvd$1k0o$1@news.iquest.net...
>>
>> One problem with 1080i or 720p is that 720p might be 720p30 or 720p60.
>> There are actually some consumer camcorders that use 720p30.
>
> Precisely. And if the last number is used to distinguish between 30p and
> 60p, why would it suddenly make sense for both 30 and 60 to refer to 60i?
>
For 720p60, that means 60 FRAMES PER SECOND. 1080i30 means 30 FRAMES
PER SECOND. Note the consistency of units.

John

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In article <TeJtc.28760$zO3.7508@newsread2.news.atl.earthlink.net>,
"FLY135" <fly_135(@ hot not not)notmail.com> says...

> This is simply your re-interpretation of terminology. The fact is that two
> fields of interlaced material has always been considered a frame and that
> usage of terminology is ubiquitous. Just because it violates what you
> consider to be the priniciple that all scans lines must be sampled at the
> same point in time, doesn't mean that calling two fields a frame is wrong.
> While your understanding of what fields are is correct, your use of
> terminology is not.

With the coming of digital television and it's 18 seperate formats
involving muliple frame rates and various means of refresh, including
interlace, segmented frame and progressive, we in the production industry
have had to re-define our terms to be more precisely descriptive. With
the old NTSC system, it was "good enough" to construct a still "frame"
from two fields exposed at different moments, even if the man waving his
hand ended up with eight fingers. In the new world of high definition
production, that sort of thing is clearly no longer "good enough".

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On Mon, 31 May 2004 15:36:52 -0600, Ron Malvern <rmlvrn@nospam.com>
wrote:

>Interlace isn't evil. It's simply a poor way to construct motion
>pictures. It introduces problems for special effects and editing at the
>post production level, and introduces grossly unneccessary interlace
>artifacts at the display level.

I agree with you 100%. In a perfect world (i.e. in a few years,
hopefully, when it comes to HDTV), everything would be 1080p. Movies
could still be 24p, and TV could be something higher. I'm looking
forward to it.

I really only had a problem with your somewhat-disingenuous claim that
you couldn't get the original progressive source back from an
interlaced product, when in fact for most film material, you can.
That's it! Otherwise I'm wholeheartedly a 1080 progressive fan. (Until
that becomes a reality, I'll have to pick and choose between 720p and
1080i...)

Well, actually I have one more problem: why can't the ATSC use common
terms everywhere, so when I go looking in an actual spec, I see the
same sorts of stuff you see when you search the site itself?? We're
both citing the same source -- the ATSC itself -- yet still can't
agree on terms!

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <%t0uc.3676$Yd3.3467@newsread3.news.atl.earthlink.net>,
"FLY135" <FLY_135(@hot not not)notmail.com> says...
> Well this the important thing, especially in light of his insistance that
> two fields of interlaced material don't make a frame. Which is clearly
> incorrect.

I'm well aware the conventional thinking is that two fields make a
frame. It's taught in all the schools and the convention has been in use
for a long time.
I'm not going to go to war over this because it's not really worth
fighting over. But we've had to change our thinking about fields and
frames with the coming of progressive scan field production gear in the
last few years.
When editing, we have to be careful nowadays about the origin of our
material and how we refer to it in technical specifications and in
editing and special effects instructions; whether a still shot, for
example, is film derived, progressive derived, segmented-frame derived,
or dual-field derived.
In this context, the still derived from two fields is going to be
inferior to a still derived from a film or progressive source because of
the timing mismatch between the fields. In this context, a lot of
editors, including me, have come to the conclusion that a dual-field
still does not qualify as a true frame, and we simply can't use it as
such.