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Loss of resolution on 2:35:1 movies?


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#1 of 14 OFFLINE   chris larralde

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Posted June 16 2001 - 04:42 AM

Greetings,

I recently purchased a 56H80 and while I realize that you get full 480 lines of resolution on 1:85 movies, I'm wondering what happens to 2:35:1 aspect ratios that still display black bars on the top and bottom? Are you still losing a percentage even thought you're using a wide screen display?

regards,
chris

#2 of 14 OFFLINE   Joseph Bolus

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Posted June 16 2001 - 05:54 AM

Chris :

As long as the 2.35:1 transfer is anamorphic, you're still ending up with a lot more resolution than you would have with a non-anamorphic 2.35:1 transfer on a legacy 4:3 set ... and you would derive even more benefit if your player is progressive.

THE BOTTOM LINE is that with an anamorphic DVD transfer, you will have enough resolution to provide a pleasing viewing experience for almost any aspect ratio ... all the way up to the 2.78:1 rendering of Ben-Hur!

Joseph

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#3 of 14 OFFLINE   Seth Paxton

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Posted June 17 2001 - 07:12 AM

Yes, Chris, you are, but that's about all you can do with a 1.78 screen size. Posted Image It's still a LOT better than if it was non-anamorphic.

Just remember that 4:3 or 16:9 both have 480 lines of picture info (NTSC standard). Without doing the math at this point, think of it this way - to make a film fit into a 4:3 area you have to reduce the width, and therefore the height. When you reduce the height you are reducing the number of sampling lines that actaully pass through the picture.

When you have a 1.85 film going to a 1.78 viewing area then you really don't have to shrink the film much (tiny LBXing occurs but is lost in the overscan area of the set). So that basically means that roughly all 480 lines go to picture info, rather than maybe 400 or something to fit a 1.33 area (again without doing the math).

2.35 will still require "shrinking" to fit a 1.78 TV, but it will be less shrinking than the 1.33 TV required. That means that maybe the 2.35 film gets 400 sampled lines of video rather than only 325 on a 1.33 TV.

As with any data, picture, graphs, audio, the more data samples you have, the more accurate a representation you have. That's what anamorphic is all about, it's simply a method that takes advantage of W/S sets to devote more sampling lines to the picture.

LBXing bars ALWAYS use up lines of video. Only "squeezing" a 4:3 picture to scan in a 16:9 area gives "LBX bars" that aren't picture info, instead in that special case you get some blank glass tube area that isn't being scanned onto.


POTENTIALLY, if all sets had various squeeze methods, you could provide a varying anamorphic standard in which all the scan lines were used for picture info no matter what aspect ratio and then the TV would just scan the lines in the appropriate area, 1.33, 1.85, 2.35, etc. But that ain't about to happen. Posted Image TV industry wouldn't want to support it for one thing, plus software side would have to deal with yet another standard. Squeeze modes require some thinking with regards to CRT beam deflection, power problems caused by such, screen burn, geometry, etc. Not enough return on investment for such an endeavor.

Rather than see this development, you will see Hi-Def DVD as the next standard to give you a big jump in picture resolution (1080 lines vs 480 lines potential sampling)

That's why we should be thankful to at least have the 1.78 anamorphic standard for now. Posted Image

#4 of 14 OFFLINE   Timmy

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Posted June 17 2001 - 01:47 PM

Quote:
Rather than see this development, you will see Hi-Def DVD as the next standard ...

If I could get HDTV resolution on my DVD's; WOW... that would be great.

But unfortunately 5 years from know we'll still be talking about HD-DVD as if its just around the corner. I won't hold my breath!

#5 of 14 OFFLINE   Abdul Jalib

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Posted June 17 2001 - 09:48 PM

I haven't quite done it yet, but I plan to set up my 4:3 Philips 60PP9601 to have a 2.35:1 hyper-anamorphic squeeze mode, with the help of my HTPC and YXY. This will squeeze all the lines of resolution of the set into a 2.35:1 area, and then 2.35 movies will be fed in without letterbox bars and hyper-stretched vertically on the PC screen so that they will be the correct ratio on the TV screen. I could use 960i for 2.35:1 anamorphic, 1080i for 1.78:1 anamorphic, and 1200i for 4:3 full screen, all with different parameter settings and convergences. Right now I'm using 1440x960i anamorphic for DVD's.


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#6 of 14 OFFLINE   RyanDinan

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Posted June 18 2001 - 04:56 AM

Quote:

I haven't quite done it yet, but I plan to set up my 4:3 Philips 60PP9601 to have a 2.35:1 hyper-anamorphic squeeze mode, with the help of my HTPC and YXY. This will squeeze all the lines of resolution of the set into a 2.35:1 area, and then 2.35 movies will be fed in without letterbox bars and hyper-stretched vertically on the PC screen so that they will be the correct ratio on the TV screen. I could use 960i for 2.35:1 anamorphic, 1080i for 1.78:1 anamorphic, and 1200i for 4:3 full screen, all with different parameter settings and convergences. Right now I'm using 1440x960i anamorphic for DVD's.

Abdul...
The only problem with this is that the anamorphic 2.35:1 transfers allready have the black bars included...because they're formatted for 16:9 TV's.
Squeezing your set to 2.35:1 instead of 16:9 will yeild a vertically squashed image that is very very narrow...
Anamorphic widescreen DVD's are meant for 16:9 displays - That's why there's still black bars on any aspect ratio higher than 16:9 (1.78:1). For your idea to work, you would need an anamorphic transfer meant for a 2.35:1 aspect TV instead of a 16:9 TV - and they just don't exist.

-Ryan Dinan


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#7 of 14 OFFLINE   Abdul Jalib

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Posted June 18 2001 - 10:39 AM

Nope, Ryan, you're wrong. YXY can remove the bars.


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#8 of 14 OFFLINE   RobertR

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Posted June 18 2001 - 01:09 PM

Abdul, you're right, but the technique you're describing can't really get you the full 480 lines of resolution--it simply isn't there. This isn't to say that what you're doing isn't useful and interesting, though. The main purpose has to do with setting up projector configurations.

Seth, a 2.35 film actually has about 363 lines of resolution on an anamorphic DVD.

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#9 of 14 OFFLINE   Abdul Jalib

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Posted June 18 2001 - 07:08 PM

Well, yeah, there aren't 480i or 480p lines of data per se there, but I'm already seeing a great benefit by upscaling 720x480p DVD to 1440x960i. I suspect one's eyes actually extract more information from the upscaled image, plus it eliminates scan lines.

I could try 1440x600p at 2.35:1 hyper-anamorphic. The picture should be brighter than normal, because it will be progressive plus hypersqueezed to use all 600 lines of resolution, so a lot more lines per inch will be painted each 1/60th of a second.


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#10 of 14 OFFLINE   RyanDinan

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Posted June 19 2001 - 01:33 AM

Abdul,
It's an interesting idea, but I think that squeezing 480 lines in a 2.35:1 area alone would cause some serious scanline overlap - Not to mention 960i (do you use powerstrip to output 960i to your Philips set?).

Even if YXY (what is that?) removes the black bars on 16:9 anamorphic transfers of 2.35:1 filmes (about 120 lines worth), you're left with about 360 lines of image data. This means that 120 lines needs to be interpolated from 360 - This means 33% of your image is going to be interpolated information - and the quality of this upconversion depends solely upon the quality of the algorithm used by the software doing it...
More importantly however, I think that with "hyper-squeezing" to a 2.35:1 area, you'll actually lose image detail and crispness because of severe scanline overlap. There's just not enough room on the CRT's to resolve 480 distinct scanlines in a 2.35:1 area - And most definately not 960i. Those scanlines would have to be VERY thin.
Most consumer HD sets can't even resolve 1080i in a 16:9 area without some % overlap...

I don't know...It sounds like an aweful lot of work for a source image of 720x480 - Which is the most realdetail you're gonna get Posted Image

-Ryan

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#11 of 14 OFFLINE   Abdul Jalib

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Posted June 19 2001 - 02:56 AM

I enjoy brainstorming on this, and I appreciate the assistance.

I use Powerstrip to convince the unruly ATI Radeon in my HTPC to supply my Philips set with 1440x960i. YXY is a program that lets you manipulate the DVD playback window/screen, to change the aspect ratio and/or blank out or remove parts of the picture.

I'm pretty sure that Philips HD RTPV's do not significantly overlap scan lines in squeezed 1080i mode. On my 60" 4:3 set, squeezed 1080i has 40 scan lines per inch, squeezed 960i has 36 scan lines per inch, and hyper-squeezed (2.35:1) 600p would have just 29 scan lines per inch. So, I think if anything I need to worry about gaps, not overlapping.

Oh drat, I just gave it a try, and the service mode won't let me vertically squeeze that much in either 600p/1200i or 480p/960i mode. So much for my dreams of a 2.35:1 hypersqueeze.


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#12 of 14 OFFLINE   Dan Crouthamel

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Posted June 20 2001 - 07:58 AM

This is an interesting topic. Would I see any visual benefit of upscaling 480p DVD to 1080i on my TW40X81 using a PC [besides testing that my HDTV inputs work Posted Image]? If so, what hardware/software is needed?

thanks,
dan

#13 of 14 OFFLINE   Abdul Jalib

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Posted June 20 2001 - 05:59 PM

You would probably see some benefit, except for the fact that your computer outputs RGB and I don't think any Toshiba set accepts RGB. Therefore, you would have to use a RGB to component transcoder, and everybody seems disappointed at the loss of picture quality when using a transcoder. I suggest waiting until the advent of PC video cards that output component video.

Also, your set is relatively small, and if you cannot currently see the scan lines, then the benefit of upscaling to 1080i may be minimal. Toshibas look very good at 480p.

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#14 of 14 OFFLINE   Dan Crouthamel

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Posted June 21 2001 - 12:57 AM

Thanks for the info Abdul.

480p DVD does look awesome on my set, especially after having it calibrated by M-TLV. I've been thinking about using a HTPC, but I'll guess I'll wait awhile for component video cards and when I get a bigger set Posted Image




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