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# On the cheap-How to get into the secret club? - Page 8

Quote:
Originally Posted by timmyotule

Expand one 1.33 times vertically. Now it is a 100:133. Zoom in 6x.

6(100):6(133) = 600 x 800

Now horizontally expand 1.33 times: 1.33(6):8 = 800:800

Now take a 100:100 image. Zoom in 8x. 8(100):8(100) = 800:800

Since a pixel is a fixed unit (on both projectors and PC LCDS) you can't simply stretch it 1.33 times. It can only be stretched by a whole number, 1X, 2X and still be an integer unit.

To scale by 1.33X requires interpolation. The simplest example of which would be to display every 3rd row twice giving the required 1.33 stretch.

Of course in practice there are advanced algorithms that are far more complicated and give a much better result. This has been touched on by previous posters.

Unless you know which algorithm your projector/scaler used and you use the same one for your PC scaling example I don't think you have a valid comparison.

Also on a single frame that you can stare at forever the difference might be noticeable, but crank it upto 60 fps and you'll never see it.

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Quote:
Originally Posted by tryingtimes

I did try and replicate it in photoshop once in this thread http://www.avsforum.com/avs-vb/showp...3&postcount=41
But I'm not sure anyone really understood what I was trying to illustrate.
It's also a pretty extreme example in that the upsampling is way more than you would find in the world of video.

That is a good illustration of upscaling. The blocks / pixels from the source in b are 5x5 while in c they are 1:1. The c image has 25 times the pixels to work with.

FYI You probably already know this but you shouldn't use .jpg since it is a lossy compression format and introduces another variable. Use .png which is lossless.

Quote:

Basically the square edges interfere with our ability to see the original sample which would be a smooth curve if rendered accurately.

BTW - I think the lamp image is a pretty good experiment, but I don't see the loss of detail that you do.

On the left I added the alternating black and white to highlight the symetrical rows of dark and light in the lamp. On the right these alternating rows are smoothed and no longer symetrical. I think the left side is probably more accurate with respect to the orignal in showing the lines in a headlight but without being able to go look at it in the real world I can't prove it.

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wrt x1.1 or 1.01 scaling. It must be theoretically possible to do a great job as all you are doing is shifting the points on a curve by a really small amount. Having a crt projector and HTPC and Crystalio II allows me to test this out in real-world. It's very hard to detect a difference.
The conclusion I've drawn for the time being is that there must be a lot of really bad scaling going on in some devices. But I remain open to other arguments.

I hear you on the bad scaling / processing out there! I've just been conditioned to be very careful when altering the source since so many implementations do a poor job.

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Anyway - if you are getting the lens and trying it for yourself, then we will have some more data to add to our discussions.

I have a lens; I'm just away on work right now.
Quote:
Originally Posted by sk8conz

To scale by 1.33X requires interpolation.

Of course it does. Welcome to the discussion. We're discussing if this is a good or a bad thing.

Quote:

Unless you know which algorithm your projector/scaler used and you use the same one for your PC scaling example I don't think you have a valid comparison.

Why don't you post some images from your scaler? Why don't you answer any questions?

I'll repeat them for you:

Care to tell us about your carefully selected equipment that provides a lovely bright image at these screen sizes?

What viewing angle do you have from your seating positions?

What shape does a pixel look like on the screen with a system using a HE or VC lens?

Quote:

Also on a single frame that you can stare at forever the difference might be noticeable, but crank it upto 60 fps and you'll never see it.

More often than not I bet you're right on this. BTW I prefer to display at 24 fps if that's what the source was shot at. Less processing.
Quote:
Originally Posted by timmyotule

Of course it does. Welcome to the discussion. We're discussing if this is a good or a bad thing.

Why don't you post some images from your scaler? Why don't you answer any questions?

I'll repeat them for you:

Care to tell us about your carefully selected equipment that provides a lovely bright image at these screen sizes?

What viewing angle do you have from your seating positions?

What shape does a pixel look like on the screen with a system using a HE or VC lens?

More often than not I bet you're right on this. BTW I prefer to display at 24 fps if that's what the source was shot at. Less processing.

Lets try and keep this on topic. It isn't about my setup or your setup. It's about your rather interesting perspective on CIH.

For the record, 140" Shearweave, ISCO III, Panny AX100 (yup not even 1080, but 2000 lumens so plenty bright). Sammy BDP1400 BRD player.

Screen has 180 degree veiwing angle, no hotspots. Seating distance - 14 feet.

SD DVDS scaled through the lens are reaching their limit PQ wise. A good transfer is fine, but so many films aren't great transfers.

SD DVD zoomed - forget it. PQ is unacceptible.

BD scaled through the lens - just stunning. I know it's only 720 lines, but that is still nearly double what I was getting off DVD.

BD zoomed - about the same as SD DVD scaled, give or take. Quite watchable, but nowhere near as good as BD scaled.

I do agree with you that 24fps is the way to go. Watched UnderWorld Evolution the other night (big letdown after the first film), but the PQ was excellent. I felt like I was looking out a window, not at a screen.
Quote:
Originally Posted by sk8conz

Lets try and keep this on topic. It isn't about my setup or your setup. It's about your rather interesting perspective on CIH.

And what do you think my interesting perspective is?

Quote:

For the record, 140" Shearweave, ISCO III, Panny AX100 (yup not even 1080, but 2000 lumens so plenty bright). Sammy BDP1400 BRD player.

Screen has 180 degree veiwing angle, no hotspots. Seating distance - 14 feet.

For the record in VTPete's '"small" screen' setup he has a larger viewing angle than you and your 'big league' setup. Just a touch larger. Basically identical though.

Quote:

BD scaled through the lens - just stunning. I know it's only 720 lines, but that is still nearly double what I was getting off DVD.

BD zoomed - about the same as SD DVD scaled, give or take. Quite watchable, but nowhere near as good as BD scaled.

Could please post some comparison shots of this? It would be interesting to see.

How do you think a 1080p zoomed setup would compare to your 720p lens setup?

You still haven't answered this one: What shape does a pixel look like on the screen with a system using a HE or VC lens?
Quote:
Originally Posted by sk8conz

Panny AX100 (2000 lumens so plenty bright).

You don't use it on dynamic do you!
Can we please take convenience out of the discussion. I realize that using a lens eliminates the indescribable hardship of having to actually get out of a chair and spend 30 seconds making a projector adjustment, but what I want to know for certain is which method (zooming or anamorphic) gives the best picture? Let's face it, extremely few people use anamorphic lenses, and the electronic wharehouse stores have never even heard of them. So where do you go to see a demonstration? There is'nt anywhere! So you end up having to make a \$6000-\$10,000 gamble on a lens and sled based on the opinions of a handful of lens enthusiasts on this forum, all of whom expound the huge gain in picture quality obtained with anamorphic, but several of whom are in the business of selling the lenses and sleds!
Maybe for some of the high rollers on this forum, spending several thousand dollars on a lens is no big deal, but for the rest of us it certainly is, we need to know for sure, going in, that the huge investment is going to be worth it in terms of picture quality alone, not just because of a trivial convenience factor. Surely with all the technical knowledge on this forum the issue of picture quality of zoom versus lens method can be demonstrateably settled (by posting comparison screen shot pictures) once and for all.
Taffman: I will be doing a comparison next week of zooming -vs- lens with my setup but the quality is something that will vary from setup to setup.

I posted a list of HD-DVDs I have in an earlier post in this thread. Let me know of any specific screen shots you'd like compared.

http://www.avsforum.com/avs-vb/showt...0#post13274660
Quote:
Originally Posted by timmyotule

You still haven't answered this one: What shape does a pixel look like on the screen with a system using a HE or VC lens?

The shape of the pixel after optical expansion or compression is now a rectangle Tim, but what that pixel contains has not changed by adding a lens, just it's shape.

Your not looking at just one pixel or a small group anyway when watching video. Your image should be made of many pixels, and the reason we have HD is simple - the more pixels the better in a given space. It is about pixel density over a given screen size where 2073600 is better than 1555200 regardless of screen size...

Mark
Quote:
Originally Posted by CAVX

The shape of the pixel after optical expansion or compression is now a rectangle Tim, but what that pixel contains has not changed by adding a lens, just it's shape.

Right, it won't be changed by an ideal lens.

Quote:

Your not looking at just one pixel or a small group anyway when watching video. Your image should be made of many pixels, and the reason we have HD is simple - the more pixels the better in a given space. It is about pixel density over a given screen size where 2073600 is better than 1555200 regardless of screen size...

The reason we have HD increases the display and source resolution which is different than just increasing panel display resolution.

Can increasing the display resolution alone improve the image? Yes it can with good scaling. I already posted about how I was impressed by the additional smoothness in the headlight image. There is slight blurring to high contrast detail but it's doubtful it'd be noticed in a film.

Hey CAVX, what viewing angle are you at from your primary seat? How is the pixel density?

Is pixel density what makes you say 'CIH done correctly uses a lens'? Do you still hold that position?
Quote:
Originally Posted by timmyotule

Right, it won't be changed by an ideal lens.

Such as your H1500FE Tim. So why don't you use it?

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The reason we have HD increases the display and source resolution which is different than just increasing panel display resolution.

True, but increasing panel display resolution is better then no increase at all...

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Can increasing the display resolution alone improve the image? Yes it can with good scaling. I already posted about how I was impressed by the additional smoothness in the headlight image. There is slight blurring to high contrast detail but it's doubtful it'd be noticed in a film.

At least we can agree there...

Quote:
Hey CAVX, what viewing angle are you at from your primary seat? How is the pixel density?

Is pixel density what makes you say 'CIH done correctly uses a lens'? Do you still hold that position?

This set up is a compromise due to a lack of space, but that changes next month. I used to be at 3.5x the image height for both zooming and then the lens.

I found that I could still see the pixels when zooming. I don't seem then with the lens, which is why I use it to this day.

The scaling in my projector is not the best, but it beats zooming hands down in my case.

In my current place, I am about 2.5x the image height, so need to keep those vertical pixels as small as I can...

Mark
Quote:
Originally Posted by stanger89

So you found two people who agree with you, vs unknown how many who have a lens because they decided it's better.

Quote:
Originally Posted by oliverg

This is beginning to sound like a virgin trying to argue about sexual performance issues .. and he's found 2 other virgins to back him up

There's another virgin to add to the list - Joe Kane.

Below is a post from Jason Turk from a thread about the Samsung 1080p Cedia demo. It started a very interesting discussion on whether a lens is an overall pro or con.

Quote:
Originally Posted by Jason Turk

I too saw this at Cedia. I didn't get the feeling when Mr. Kane said "under \$10k" it was going to be way under \$10k...

On thing I sort of understood his point on, but personally disagreed...anamorphic 2.35:1 setups. He doesn't believe in them, so there is no built in vertical stretch. Not a total deal breaker, but, that means whatever it prices out at, you'll need to get an outboard video processor as well. I think they were the only one with a new model NOT supporting vertical stretch at the show.
Yeah, but isn't Joe Kane a CRT man?

Mark
Quote:
Originally Posted by CAVX

Yeah, but isn't Joe Kane a CRT man?

Mark

I don't think so - he's worked closely with Samsung (i.e. not just lending his name) developing two DLP projectors (720p and 1080p).
Quote:
Originally Posted by ilsiu

I don't think so - he's worked closely with Samsung (i.e. not just lending his name) developing two DLP projectors (720p and 1080p).

Well hopefully he'll come around

Mark
Quote:
Originally Posted by CAVX

Such as your H1500FE Tim. So why don't you use it?

It won't physically fit in my current setup. Well, I could get it to fit probably but that would probably mean lowering projector even further to the point where one seat on the couch would put a person's head in the light path.

My projector is placed behind the back wall underneath a nook under the stairs into the basement. I was originally planning on putting it on the ceiling but the throw ratio was going to be just barely long enough.

Tucking the projector behind the back wall really makes a clean install. Not to mention the head knocking hazard from a projector and lens installed with 6.5' ceilings!

I could maybe modify my hole in the back wall to get the lens in there but it's ceder paneling which isn't the easiest to patch back up if you want to go back. And the combination of studs and floor joist make fitment a big problem. I'd have to get up and go turn the two knobs on the lens anyway even if I could get it to fit (or pay another \$500 for the remote option, which is tempting...).

I'll check it out next week but I just don't see their being a \$2000 benefit from it anymore. Who knows though. Everytime I think about the full automation it sure sounds sweet.

Quote:

True, but increasing panel display resolution is better then no increase at all...

At least we can agree there...

Yeah, I admit that my little test shows that the increase in even 1.33x vertical resolution provides a noticable increase in smoothness. At some view distance this won't be noticable. At what point? I'll leave that to the visual acuity gurus. There is still the smoothing of contrast lines that is a slight negative but the benefits look to out weigh the positives.

Quote:

This set up is a compromise due to a lack of space, but that changes next month. I used to be at 3.5x the image height for both zooming and then the lens.

I found that I could still see the pixels when zooming. I don't seem then with the lens, which is why I use it to this day.

The scaling in my projector is not the best, but it beats zooming hands down in my case.

In my current place, I am about 2.5x the image height, so need to keep those vertical pixels as small as I can...

Mark

Here's the crux of what I'm getting at. CIH can work with both a lens and by zooming. My setup zooming has a higher pixel density than 720p users with a lens. Over 12% more vertically. 50% more horizontally.

Does that make your system not one that is done correctly? No. If someone has even more resolution with a 1080p projector and a lens does that make my setup incorrect? No.

It sounds like you can't see the pixels at 2.5x the image height. I sit at 2.7x the image height and likewise can't see the pixels with my setup that is using 633600 more pixels. My total pixel count is 69% more than your setup. Will adding even more resolution improve the picture quality a noticable from where I sit? Possibly. But with my short throw there will be some geometric distortion and chromatic aberration introduced along with the added cost. Tradeoffs. Compromises. Still correct.

People need to stop saying something is incorrect just cause their is something out there that is possibly better.

People need to stop saying zooming is 'wasting precious pixels' when the zoomers already more resolution then they do.
Quote:
Originally Posted by timmyotule

For the record in VTPete's '"small" screen' setup he has a larger viewing angle than you and your 'big league' setup. Just a touch larger. Basically identical though.

Maybe I'm missing something, but how could anyone have a viewing angle larger than 180 degrees? Is he watching from behind the screen?

Quote:
Originally Posted by taffman

So where do you go to see a demonstration? There is'nt anywhere! So you end up having to make a \$6000-\$10,000 gamble on a lens and sled based on the opinions of a handful of lens enthusiasts on this forum, all of whom expound the huge gain in picture quality obtained with anamorphic, but several of whom are in the business of selling the lenses and sleds!

I'm not sure why you decided to put those numbers in when you sat down to type the post, but you end up discrediting your own argument when you're low number is 10x what some of us spent for the lenses we bought. I guess I don't have a sled though, and haven't really looked into them, so maybe that's where the other \$5400 of expense goes.

Yes, it sucks that there's no place to go demo them all before we buy. I like what someone said before - start with the cheapest thing you think might work and then upgrade as needed from there. Not only did it not cost me \$6000-\$10000 to "gamble" on my lens, but had I ended up thinking it wasn't any better than zooming, I probably could have sold it aftermarket for \$500, and my lost "gamble" would have cost me a whopping \$100. At a price like that, I can't figure out why anyone struggling to decide whether to add a lens to their setup wouldn't just go ahead and buy one to try out themselves in their own setup.
Quote:
Originally Posted by popechild

Maybe I'm missing something, but how could anyone have a viewing angle larger than 180 degrees? Is he watching from behind the screen?

The viewer's viewing angle. AKA the angle from your head to the side edges of the screen. AKA the screen height to seating distance ratio.
Hey CAVX (do you prefer that or Mark?),

I was thinking about the 720p lens setup. I wonder if it converts it to 720p before or after doing the scaling. Do you send the projector a 1080 signal or 720?

Hopefully it does a down conversion scaling of the 1080 signal. Have you tried testing it?
Quote:
Originally Posted by timmyotule

Hey CAVX (do you prefer that or Mark?),

I was thinking about the 720p lens setup. I wonder if it converts it to 720p before or after doing the scaling. Do you send the projector a 1080 signal or 720?

Hopefully it does a down conversion scaling of the 1080 signal. Have you tried testing it?

That's a very good point. If (as I'd assume) they scale from 1080i, then you are getting real extra resolution when using a 1080 source.
Quote:
Originally Posted by timmyotule

The viewer's viewing angle. AKA the angle from your head to the side edges of the screen. AKA the screen height to seating distance ratio.

Still confused. You said two different things. I understand what screen height to seating distance ratio is, but have never heard that called a viewing angle. (For one thing, it's not an angle at all, but a...umm..ratio.)

As far as "the angle from your head to the side edges of the screen," I'm not clear on exactly what you mean, so I'm not sure if that's what I'd term a viewing angle or not. I still have no idea how that could be more than 180 degrees. Please explain exactly what you mean by this (maybe an example would help?)

FWIW, wikipedia defines viewing angle the same way I've always seen it referred to - ie. "the maximum angle at which a display can be viewed with acceptable visual performance." Incidentally, it also says that "The viewing angle is measured from one direction to the opposite, giving a maximum of 180Â° for a flat, one-sided screen."
Quote:
Originally Posted by popechild

Still confused. You said two different things. I understand what screen height to seating distance ratio is, but have never heard that called a viewing angle. (For one thing, it's not an angle at all, but a...umm..ratio.)

As far as "the angle from your head to the side edges of the screen," I'm not clear on exactly what you mean, so I'm not sure if that's what I'd term a viewing angle or not. I still have no idea how that could be more than 180 degrees. Please explain exactly what you mean by this (maybe an example would help?)

FWIW, wikipedia defines viewing angle the same way I've always seen it referred to - ie. "the maximum angle at which a display can be viewed with acceptable visual performance." Incidentally, it also says that "The viewing angle is measured from one direction to the opposite, giving a maximum of 180Â° for a flat, one-sided screen."

I think he's referring to 'field of view' angle.

(I agree that most people share you definition of viewing angle)
Field of View may be a better term but viewing angle also gets used a fair amount in this forum. Viewing angle is also what THX calls it for whatever that's worth. Interchangable terms.

http://www.avsforum.com/avs-vb/showt...php?p=12867220
http://www.avsforum.com/avs-vb/showt...e#post13042884
http://www.thx.com/home/setup/display.html

And on and on...
Quote:
Originally Posted by popechild

As far as "the angle from your head to the side edges of the screen," I'm not clear on exactly what you mean, so I'm not sure if that's what I'd term a viewing angle or not. I still have no idea how that could be more than 180 degrees. Please explain exactly what you mean by this (maybe an example would help?)

For viewing angle, if we define it as the angle from left to right side of the screen from the viewers perspective, in order for it to be 180 degrees, the viewer would have to be 0 feet from the screens surface.

However I think what sk8conz meant by viewing angle is the LCD TV definition, where it's the angle (relative to the screen) where the brightness is roughly equally bright, meaning basically the screen is the same brightness from any angle, ie exactly what you got from wikipedia.
no matter what you ment, viewing angle or field of view, an angle above 180Â° is impossible on a flat screen
follow the THX link you posted and look at the 1st picture, it doesnÂ´t matter where you start with the angle, from the screen or from the viewer, but usually viewing angle means the angle which the person is standing and looking upon the screen and the angle is starting from the center of the screen, 180Â° is the absolut maximum you can achieve, well actually 180Â° is impossible since you canÂ´t look around the corner, from 180Â° you would just stare @ the frame

however if you ment the "height angle" in the 2nd pic the maximum you could achieve is 90Â° but only with a domelike screen that ends directly avove your head
so the "bigger than 180Â° viewing angle statement" is simply wrong no matter how you turn it
Quote:
Originally Posted by timmyotule

The viewer's viewing angle. AKA the angle from your head to the side edges of the screen. AKA the screen height to seating distance ratio.

A 2.39:1 Scope screen, veiwed from 3.68x the image height gives a veiwing angle 36 degree...

Mark
Quote:
Originally Posted by Theron2

the "bigger than 180Â° viewing angle statement" is simply wrong no matter how you turn it

Good thing I never said that
Quote:
Originally Posted by timmyotule

Hey CAVX (do you prefer that or Mark?),

I was thinking about the 720p lens setup. I wonder if it converts it to 720p before or after doing the scaling. Do you send the projector a 1080 signal or 720?

Hopefully it does a down conversion scaling of the 1080 signal. Have you tried testing it?

Mark is good though CAVX works too

My understanding of the scaling process is that it simply allows the projector to zoom in on the centre portion of the image discarding the top and bottom portions, hence the black bars. The media (both SD and HD) is normally electronically stretched by the display. When we have a display that allows the so called "Vertical Stretch" is means that it does not lock to 16:9 mode. This "lock" was introduced to prevent consumer confusion about HDTV and geometry, ensuring that the end user would always see goemetry correct images.

In CIH using a lens, we are by default not doing what the manufacture originally intended, so we want to see our image with incorrect geometry so we can correct it optically with the lens.

Whilst HD media is native 16:9, it still requires the display to electrically stretch it for goemetry correct images, and why even though it is not true anamorphic material, work for CIH with the lens.

Whilst some scaling algorthims works better than some, using the projector to scale is kind of like taking a 4 x 3 (12:9) image and zooming it to fill the 16:9 panel width. When blown up to be the same width, the 4 x 3 image is actually taller, and the pprojectors like SONY WV60 seem to simply chop off the top and bottom of that frame. Because the top and bottom contain black bars, this is desirable for CIH with a lens.

This is a really simplified explaination, but it seems to be the same from projector to projector that allow this to happen, but to test this theory, simply set the source to 4 x 3, and this will simply "zoom" the image.

So even though HD media is not considered "anamorphically enhanced" the way SD versions are, they still need the "electric stretch" to be performed by the display...

Mark
Yeah Mark, I got all that, I don't think I was clear in what I was getting at. What I'm wondering is if you're sending your projector a 1080 or 720 signal. And in what order the projector performs the conversion to 720p and vertical stretch.

If you're sending a 720p signal then your projector gets 1280x540 scope image to work with. It verticall stretches this image to fill the panel and projects it.

If you're sending a 1080i/p signal the projector has to convert it to 720p to display it. If it does this before the vertical stretch process then it will be doing the stretch again working with a 1280x540 resolution image. But if it does the vertical stretch first it could scale a 1920x810 image to the panel resolution of 1280x720 (or it may even do both at the same time). There would be a lot more information to work with and it would only be downscaling the vertical resolution slightly.

If it's doing the vertical stretch first you would be using more information from the source versus zooming out a 1280x540 image and you would see a lot more detail in the image.
Quote:
Originally Posted by timmyotule

Good thing I never said that

My bad. Not sure where I could've got that.
Quote:
Originally Posted by sk8conz

Screen has 180 degree veiwing angle, no hotspots. Seating distance - 14 feet.

Quote:
Originally Posted by timmyotule

For the record in VTPete's '"small" screen' setup he has a larger viewing angle than you and your 'big league' setup.

Is this where I do the eye rolling smilie?
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