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well, if you ask ME 24pSf is interlaced, but if you ask a sony guy
they'll tell you that it's progressive, but segmented. hence their
designation.
while i appreciate your striving for technical accuracy, you're kinda
spitting into the wind. convention has taken over.
1080i is gonna mean 1080i/59.94 FIELDS
24p is gonna mean 1080p/23.976 FRAMES
except when it doesn't.
david friedman
On Monday, August 29, 2005, at 09:19 AM, Mathew Sherman wrote:
David, 24P is not the whole story AGAIN! Saying 24P tells you nothing.
Saying 1080p/24, now that's the whole story. Now I know it's a 1080P
format
(1920x1080 progressive frames and this does not yet exist on tape) and
there
are 24 of them per second captured. That is different than saying
1080/24PsF. Sony HDCAM is 1080/24PsF and, my friend, it is still
technically
1080i. It is still stored as two separate fields on the tape. Sure,
they can
be recombined into one progressive frame and they are both captured in
the
same moment in time, which is what Rich is explaining. And, all my
friends,
this is now all sounding a bit silly. My main comment from my first
post is
not to confuse 1080i as absolutely meaning 59.94 fields. Cause
couldn't it
be 50i? That's all. I know in North America it's becoming convention,
typically American to only think everyone is doing what they are.
(Sorry,
flame me if you don't agree, I'm American too so....) But if you are in
international post house and deal with European HD formats such as 25P
and
50i then it's important to specify the difference. That's all.
Matt Sherman.
-----Original Message-----
From: david friedman [mailto:gevalt1(at)gmail.com]
Sent: Sunday, August 28, 2005 11:24 PM
To: DS(at)Softimage.COM
Subject: Re: 1080i format question
ok, there IS a lot of confusion about HD even among professionals.
imagine what the CONSUMERS are going through.
24P is NOT 1080i. if anything you should refer to it as 1080P/24fps
(or 23.98fps)
now that isn't to be confused with those 24p dvc pro cameras that
capture at 24 fps and add pulldown in the camera, because those tapes
end up as 29.97fps NTSC
david friedman
On 8/28/05, tony(at)hdheaven.co.uk <tony(at)hdheaven.co.uk> wrote:
Hi Guys,
Surely the "i" at the end of 1080i means "Interlaced" doesn't it?
Which
would differentiate it, for instance from 1080PsF.
In other words, 1080 specifies the line count, i means interlaced, and
then other information is requred to specify frame rate?
So, 24P couldn't be called 1080i.
Or have I completely misundertood something here?
Cheers,
Tone :)
Mathew Sherman wrote:
Yet again I must remind everyone that saying "1080i" does not have
anything to do with frame rate. People are getting confused when
people tell them "we need 1080i" that it somehow precludes them from
working at 24PsF. But the only thing truly that 1080i means (in this
case I am referring to the HDNet spec) is that they do not want 720P
originals. Sony HDCAM is a 1080i format regardless of what frame
rate
you are using. 24P is also 1080i and that is exactly what HDNet
means.
They don't like DVCPRO-HD since it's low bit rate (100Mbps) and is a
720P format (natively).
In terms of what to do for a possible film-out well definitely
working
progressive will help the film look better, however these days there
are such good de-interlacing tools that I bet one would have a hard
time telling the difference between 59.94i (proper term) or
23.976PsF
on the cinema screen once all is said and done, properly.
Sorry to disagree Matt but in the US 1080i has become synonymous with
59.94 fields. Mark Cuban was involved in a discussion on the Telecine
Internet Group last year on this topic. He was quite adamant that the
research they've done on viewer preferences were so strongly in
favor of
the higher frame rate that they chose to require that for delivery.
I'm
not surprised since Mark Cuban is so involved with sports
broadcasting
and the higher temporal resolution makes a difference. I happen to
prefer 720p for sports for the same reason - disclaimer: I'm ex-ABC
engineering.
If you're planning a film out there is a big advantage to working in
24p
(again, common usage in the US translates to 1080psf(at)23.97 - even for
film jobs you'd need to specify true 24p if you didn't want
23.97psf!).
Yes, there are de-interlace tools but it doesn't look the same and
we've
been through it on numerous projects.
--
Richard Torpey
VP Engineering
Rhinoceros/MultiVideo Group
50 East 42 Street
New York, NY 10017
(212) 986-1577
(212) 986-3833 fax
(212) 692-4465 direct
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