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Discussion Starter · #1 ·
My first projector was a Sony SVGA with 450 ANSI Lumens and no 16:9 mode. Watching anamorphic DVDs I was faced with the choice of letterbox within the 4:3 format or a type of 'pan & scan' version by using the horizontal size control on the projector to essentially 'lose' a full quarter of the picture on the right side of the screen. The H size control was sufficient to unsqueeze the image, but the loss of picture was always on one side, which is worse than pan & scan which generally centres the image around the main activity.


I was never quite sure which option to use because the unsqueezed image was clearly better quality but the letterboxed contained all of the picture. I was caught between a rock and a hard place, as the saying goes.


I remember searching the net at the time - about 4 years ago - but never came across an anamorphic lens designed for digital projectors. It wasn't until I came across this marvelous forum that I learned of the existence of such lenses and I seriously considered buying either a Panamorph or ISCO to upgrade the Sony projector instead of getting a new projector. Well, I opted for the new projector (let's face it, 450 lumens is a serious disadvantage).


However, I'm still searching for that increased vertical resolution that the Panamorph promised. It undoubtedly works with SVGA projectors. But what about SXGA projectors? I can't see any advantage with DVD apart from increased brightness (partially offset by a few small negatives).


1080i is a slightly sore point with me at the moment because of panning and motion artifacts. I can only receive the Aussie HD signal in RGB mode on the SX5500. I'm not sure if it's just that the RGB mode on the Hitachi is deficient in it's de-interlacing capacity, or whether 1080i in general presents some difficult de-interlacing challenges. (Why any HD format includes interlaced is beyond me - but that's another rant).


I've recently been studying the 'squeezed' HD transmission in a 4:3 format, trying to determine if there's any increase in detail. It's difficult because (a) the H size control on the Hitachi is very limited - not nearly enough to unsqueeze the image, and (b) the freeze control is immediately de-activated when switching formats.


The impression I get is that motion artifacts are less prominent in squeezed 4:3 mode. Perhaps it follows that REAL vertical resolution is also greater. I'd like to think so and it's very easy to jump to the conclusion that this is so. Can anyone verify that this is so? Has anyone gone to the trouble of checking this out? In the past I've often come a cropper by making assumptions.
 

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Quote:
Originally posted by barryz



However, I'm still searching for that increased vertical resolution that the Panamorph promised. It undoubtedly works with SVGA projectors. But what about SXGA projectors? I can't see any advantage with DVD apart from increased brightness (partially offset by a few small negatives).
barryz,


The Panamorph will work with any resolution projector. The Panamorph works optically - on the light beam produced by

the projector - quite independent of how many pixels are in the image.

Quote:


1080i is a slightly sore point with me at the moment because of panning and motion artifacts. I can only receive the Aussie HD signal in RGB mode on the SX5500. I'm not sure if it's just that the RGB mode on the Hitachi is deficient in it's de-interlacing capacity, or whether 1080i in general presents some difficult de-interlacing challenges. (Why any HD format includes interlaced is beyond me - but that's another rant).
Interlacing buys you more image lines without increasing the bandwidth. A 1080i image has the same bandwidth requirements

as a 540p image. So for a given bandwidth, you get more lines of resolution. You might inquire as to why not broadcast

the 1080 lines as a progressive signal - 1080p?


That would double the bandwidth requirements - and since there's a limited total bandwidth available - you would

wind up with half as many HD channels available.


Are you using the internal scaler/de-interlacer in the Hitachi? Most internal units can't compete with an external

scaler like the Faroudjas, or an HTPC. There's nothing especially difficult about de-interlacing 1080i. As long as

you have the processing capacity to handle the data, the

de-interlace algorithms are the same.


Dr. Gregory Greenman

Physicist
 

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Discussion Starter · #3 ·
Quote:
Originally posted by Morbius



Are you using the internal scaler/de-interlacer in the Hitachi? Most internal units can't compete with an external

scaler like the Faroudjas, or an HTPC. There's nothing especially difficult about de-interlacing 1080i. As long as

you have the processing capacity to handle the data, the

de-interlace algorithms are the same.


Dr. Gregory Greenman

Physicist
Greg,

Thanks for your response. Yes, I'm using the internal scaler/de-interlacer in the Hitachi. I understand that the Panamorph works in the optical domain independently from the internal electronics of the projector, so my question really is about whether or not the internal scaler/ de-interlacer of the Hitachi justifies the addition of a panamorph into the system.


If it doesn't, would an ATI Radeon 8500DV AIW make it worthwhile, because this seems to be the best card for an HTPC that I know of? Sorry if I'm straddling forum sections with this question.


Having said that, it's just occurred to me (hence the editing) that the 8500DV is not capable of accepting and processing a 1080i signal at 50hz, so it seems I'm stuck with the internal scaler/de-interlacer of the Hitachi in RGB mode (28.2kHz at 25hz).
 

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I am not so failure with the quality of the scaling/deinterlacing inbuilt within the 5500, but I have had the Panamorph for a long time, and seen it on everything from an Lcd to a Dlp, Dila. One of the noticeable things that never seems to get much of a mention is because the Panamorph squeezes more pixels into the image it seems to lessen (to a the naked eye) some of the moire and other artefact's.


Perhaps you could try to arrange a money back guarantee period and try one for yourself. With HD from Hbo/Sho/Cbs/Abc into the 5500's 1365x1024 pixel array it should look very good. My friend's Jvc G15 Dila which has the same pixel array looks vastly better than it ever looked with 1365x768. But lets face it my opinion is not your opinion.



DavidW
 

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"However, I'm still searching for that increased vertical resolution that the Panamorph promised. It undoubtedly works with SVGA projectors. But what about SXGA projectors? "


The Panamorph works the same with both types of projectors, if I understand your question correctly. :) Obviously the lens can't can't increase the resolution of the source, but it can bring more resolve to the screen by using more of the projectors panel.


"I can't see any advantage with DVD apart from increased brightness"


Well, for starters, you're using the entire 4:3 panel of your Pj for viewing 16:9 material, and with the 2.35 discs, you'll still get a 33% increase in panel usage with the Pannie.


Also consider the lack of light spill above or below the screen with all 16:9 material, which 99% of all Hi Def currently is. For me, that was a biggie. My background walls are off white, so the light spill had an adverse effect on the viewing experience.


Chris
 

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Quote:
Also consider the lack of light spill above or below the screen with all 16:9 material, which 99% of all Hi Def currently is. For me, that was a biggie.
Chris thats another biggie for me as well. The redirection of the light into the picture rather than the black bars is a must have for a digital projector and effects the contrast ratio as well as the whole depth of the image.

You have the DILA like a friend and because it has a native 1365x1024 panel I must admit it works much better for 1920x1080 source material than my 1024x768 or 1280x720. To me a 1365x1024 panel is a pretty good match for a 1080 image.


DavidW
 

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Discussion Starter · #7 ·
Quote:
Originally posted by CCLAY



Obviously the lens can't can't increase the resolution of the source, but it can bring more resolve to the screen by using more of the projectors panel.


Chris
By 'more resolve to the screen' I presume you mean 'preserve the scaling'.


I'm actually slightly confused here, believe it or not! We're all agreed that the panamorph cannot increase the resolution of the source. But what it can do, it seems to me, is preserve the resolution of the source if such resolution is compromised in the unsqueezing of an anamorphic source, as is the case with PAL anamorphic on an SVGA projector, and possibly 1080i anamorphic on an SXGA projector. The two situations seem analagous to me. 576i anamorphic, unsqueezed, occupies the whole of the 4:3 SVGA screen. 1080i anamorphic, unsqueezed, occupies the whole of the SXGA+ screen (give or take a bit). Unsqueezing in both cases will degrade the original source. The panamorph makes it unnecessary to unsqueeze, thus preserving the full resolution of the source in both cases. By that line of reasoning, I should buy a Panamorph without delay, and I guess I probably would if there were more HD material out there.


When it comes to the 2.35:1 aspect ratio, I'm confused again. How can the Panamorph help? A 2.35:1 ratio within the 16:9 format of all modern displays is analagous to the non-anamorphic letterbox within the 4:3 format of old fashioned displays. There are black bars in both cases which represent lost vertical resolution. You could argue that the black bars of the 2.35:1 situation within the 16:9 format are narrower and therefore the loss of vertical resolution is less, and you may be right. I haven't done the maths. But the principle's the same.


Now there might be something else going on here which I can only guess at. The native resolution of DVD is 720x480/576, and that applies to both widescreen and 4:3. The only transfers that I've seen that appear to fully use the capacity of the medium are the box office films where lots of money is available to do a good job. Most of the 4:3 DVDs are rubbish from the technical point of view, which is sad because there's a lot of good material in the 4:3 format and it needn't be that way. It's my view that if anyone producing a 4:3 DVD from a high quality source were to pull out all the stops, the result would knock your socks off.


There's another issue that I think needs clarifying and it relates to Disney's policy of producing 4:3 DVDs from its films, much to the angst of this forum's David Boulet. It's my suspicion that many DVDs that have the 4:3 format on one side and the widescreen on the other - I'm thinking of films such as 7 Years in Tibet (NTSC) and Evita (PAL) - do not contain a remastered 4:3 version, but a 'blown up' section from the one and only widescreen master. That makes a world of difference. So, if Disney are making a 4:3 master for some of their DVDs, then 'good on them'. The clarity and detail SHOULD AND COULD exceed any widescreen transfer. The laws of Physics are such. More picture - less resolution. Less picture - more resolution.
 

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The more pixels you bring to bear on the image the better, regardless of resolution of the input.


I believe there was a post of KBK a while ago showing this in pictures.


For example, let's say you have a 1024x576 image. On XGA, you show it 1-to-1, so you might think that's ideal. If you have an anamorphic lens, you scale it vertically to 1024x768, then optically compress it to 1024x576. The pictures showed that the 1024x768 + lens in fact looks better. The bicubic interpolation makes gradations smoother, and I guess in general makes the image look less pixelated. It doesn't matter that you've gone to a greater resolution than the source itself.


Mike
 

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Discussion Starter · #9 ·
Well that's settled then. I'll put the Panamorph on my shopping list. Thanks all for your help.


- - - unless someone wants to talk me out of it.
 
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