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1080i vs. 1080p clearly explained - finally!

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Old 09-15-2006, 07:32 AM   #46  
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Yeah, I wasn't disagreeing with you, just elaborating. Actually avoiding the pull-down to 30 (or 60) Fps is a good reason to want a 1080p/24 output and 1080p/24 input.

Yes, I know that with proper reverse pull-down everything will be recovered, but why take 1080p/24 disc content, interlace it and pull it down to 1080i/30 (in the player), then perform reverse-pull-down and de-interlace it back to 1080p/24 (in the display) if you don't have to?

And, as you indicated, unless your display has a refresh rate that is a multiple of 24Hz, you essentially add the pull-down judder back in when you display 24Fps on a 60Hz refresh display.
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Old 09-15-2006, 11:12 AM   #47  
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Only source I expect for 1080p/60 would be video games. I think for everything else, people would be happy with 1080p/24.
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Old 09-16-2006, 05:31 AM   #48  
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Default 1080p hoopla.....

Let's face it folks, the cat is out of the bag....1080p, much ado about nothing.
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Old 09-16-2006, 12:46 PM   #49  
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Quote:
Originally Posted by hdrichtv
Let's face it folks, the cat is out of the bag....1080p, much ado about nothing.
If you mean 1080p/60, I would agree. 1080p/24 would be very nice for movies. Just saying 1080p does not describe a format fully.
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Old 09-17-2006, 05:43 PM   #50  
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Hdrichtv-

Did I ever mention there are a number of displays (including 1080p displays) that don't de-interlace 1080i properly?
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Old 09-18-2006, 03:12 AM   #51  
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The issue is not defective TV's, but rather will 1080i vs 1080p HDTV's show any difference from broadcasts or movies. Read the threads, read the articles embedded in the threads. The answer is clearly --no. I stand by the statement--1080p, much ado about nothing.
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Old 09-18-2006, 03:26 AM   #52  
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Quote:
Originally Posted by BobY
...Did I ever mention there are a number of displays (including 1080p displays) that don't de-interlace 1080i properly?
Quote:
Search: Key Word(s): de-interlace ; Posts Made By: BobY
Showing results 1 to 25 of 26
Yes and that doesn't include "de-interlacer"
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Showing results 1 to 25 of 27
Search: Key Word(s): de-interlacer ; Posts Made By: BobY

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Old 09-18-2006, 07:58 AM   #53  
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Oh yeah, thanks for reminding me! Did I ever mention there are a number of displays (including 1080p displays) with bad de-interlacers?

And some, I suspect, which won't perform reverse pull-down properly on 1080i content?

Since there's no way a consumer can test for those things, any of those issues can be avoided by using a 1080p/24 output into a 1080p/24 input, which more and more manufacturers are beginning to offer.

I say: "1080p, Bring it On!" It doesn't matter even if it is much ado about nothing, it's where the HD world is headed.

Seriously, though, the above article was the first one that even *mentioned* that there are displays which can't de-interlace 1080i to 1080p. It is theoretically true that 1080i (made from a 1080p source) can be de-interlaced perfectly back to 1080p, but that assumes the de-interlacer only weaves the fields and that, in turn, assumes the de-interlacer recognizes the 1080i content is film-based and doesn't do anything other than weaving. Based on the realities of the CE market, which always cuts corners to maximize profits, I think it's really optimistic to assume the vast majority of displays do it properly. Who would have thought that on such a flagship product as their HD DVD players, Toshiba would have trashed the 720p output by upscaling 540-line fields to 720-line frames instead of downscaling 1080-line frames to 720-line frames? Who would have thought Samsung would achieve their 1080p output by not simply transmitting the 1080p content as is, but rather processing it at 1080i, then kludging on a de-interlacer chip to convert it back to 1080p? Just some food for thought...

Last edited by BobY; 09-18-2006 at 08:10 AM..
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Old 09-18-2006, 08:27 AM   #54  
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Are you sure that Samsung is doing that in their 95 and 96 series? The logic behind interlacing a progressive signal, then electronically stitching it back to a progressive signal fails me...
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Old 09-18-2006, 09:04 AM   #55  
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Sorry, I was referring to Samsung's much-maligned Blu-Ray player. It was originally designed to output only 720p and 1080i, but when the product introduction was delayed and they saw that 1080p was becoming a marketing hot-button, they needed some way to quickly add a 1080p output.

All they did was slap a Faroujda de-interlacer chip on the existing 1080i output (so the player is doing nothing more than any HDTV with a good de-interlacer would do). It's strictly for marketing reasons--in this case I agree it's much ado about nothing. Wait a minute...suppose the de-interlacer chip doesn't de-interlace 1080i properly and instead bobs the image...nah...couldn't be.

Or could it?
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Old 09-18-2006, 11:28 AM   #56  
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As long as there are possibilities that TVs aren't properly deinterlacing an incoming 1080i signal, there's value to 1080p/24 output source equipment and TVs that support 1080p/24 input. So I agree with BobY that it simply isn't a "much ado about nothing" scenario.
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Old 09-18-2006, 01:27 PM   #57  
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This thread started out with some new information in the OP -but the other 54 unsourced posts seems to be flogging all the same ideas that have been posted 100s of times around here over the last year - This article seems to be the basis for a lot of the later posts - maybe it's time for anyone who didn't read it - or doesn't have a perfect recollection - to read it
it's not the latest news - it's about 2005 models - but it's only 4 months since it was published -
Are You Getting All the HDTV Resolution You Expected? by G. Merson
BTW the older link in the OP from Aug 7 has been updated here http://blog.hometheatermag.com/geoff...1606more1080p/ on Sept 8 by the 'other GM' G. Morrison
also read his last article You don't need 1080p

Last edited by maicaw; 09-18-2006 at 01:54 PM..
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Old 09-18-2006, 06:44 PM   #58  
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Excellent links!

BTW, I'm on the verge of proving that my Toshiba CRT-based HDTV *does not* perform reverse pull-down on 1080i content. The manual implies that Cinema mode only operates on DVD's at 480i and the schematics show there is not nearly enough field memory to compare multiple fields at 1920 x 540 in order to determine cadence. From this one might conclude that is possibly a limitation of all Toshiba HD CRT's and, presumably all Orion HD CRT's since they are based on Toshiba electronics.

OK, it's an interlaced display, so who cares? Well, if a progressive scan display doesn't properly detect film cadence and switch de-interlacing mode to film (weaving) mode, then you will *never* reconstruct the original 1080p frame from a Hi-Def player when using 1080i output.

Are there any progressive displays out there that don't detect film at 1080i? Here's an easy test:

Use either an HD DVD player or a Blu-Ray player and select 1080i output. Play a movie for a few minutes (to give the display time to detect cadence and lock into film mode). Press "Pause" during a scene with some moderate amount of motion (say a close-up of someone speaking, or someone walking across the room), then single step from that point. If the display is properly detecting film content, you should see some change in the frame each time you single step. If you see frames being repeated (i.e., no difference in two frames in a row), then the display is not detecting film content at 1080i, the de-interlacer is not in film mode and, even if it's the best video mode de-interlacer in existence, it is *not* recovering the original 1080p frame.

Anybody wanna try it and let me know the results?
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Old 09-18-2006, 07:13 PM   #59  
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I don't think that will work because the TV, if detecting the cadence, does that on the fly within a few frames. Since on pause or single step it will be detecting frames, or fields, of identical information there will be no 3:2 cadence.
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Old 09-18-2006, 07:55 PM   #60  
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Rats, that's probably true. But as I understand it, most displays don't detect cadence continuously, rather they switch into film or video mode and stay there until they detect a change in cadence, which is tested periodically, but not continuously.

That was a complaint with some DVD's that mixed movie and video content (like special features that switched between film outakes and video-based interviews), they wouldn't detect the change in time and by the time they did, it had changed again.

Got any good ideas for how to tell if a display is performing reverse pull-down on 1080i?
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