AVS Forum banner

Status
Not open for further replies.
1 - 20 of 26 Posts

·
Registered
Joined
·
2,584 Posts
Discussion Starter · #1 ·
I suspect that most external scalar owners are using their devices to drive 16:9 screens and that most of those screens are burn-in susceptible (e.g. plasmas). This means that if we watch typical 4:3 standard definition material a lot we really need to stretch the material to fill the screen.


I find that standard defintion tv (Time Warner Cable) looks much better on my plasma when piped through my Leeza (no surprise there), but if I want to fill the entire screen while using my Leeza for 4:3 material I've got only two choices: zoom so that a large amount of the top and bottom are cut off, or linear stretch which looks absolutely terrible (obese talking heads).


Most of the time, I end up bypassing my Leeza altogether for standard defintion material (Time Warner cable through my Replaytv), because my plasma (a pioneer 503cmx) allows me to employ a 'wide' mode which looks surprisingly good (the center of the picture isn't streteched very much and the sides are stretched more to compensate; this results in an image that is far less distorted looking than the image you get with a linear stretch). I would love to have that mode available in my Leeza, and I strongly suspect that this feature could be included in a software upgrade if there were enough demand for it.


So, my question is this, for all you scalar owners out there: would this be an important feature for you?


(I've received several private messages from people who have not yet purchased scalars saying that lack of wide mode is the thing that's holding them back, so I know there is some interest for this feature out there.)
 

·
Banned
Joined
·
1,400 Posts
It is possible to re-create this in the Leeza by using the custom aspect ratios. I have never played with them and have no idea how they work, but it is posible to tailor the amount of image stretch and where it stretches in the custom mode. At least, i think that's where it can be done, as i said, I have never tried it or played with it. You should ask Mike to actually do one and forward the exact settings to all of us to copy as our own. Maybe I can ask him next time we speak.
 

·
Registered
Joined
·
2,584 Posts
Discussion Starter · #3 ·
Quote:
Originally posted by ericbee
It is possible to re-create this in the Leeza by using the custom aspect ratios. I have never played with them and have no idea how they work, but it is posible to tailor the amount of image stretch and where it stretches in the custom mode...
Actually, Mike told me a while ago that you can't do a non-linear stretch under the current software (but that he might be able to add it as a feature if there were enough demand).


Perhaps you're thinking about using the custom ratios to create a combination of zoom and linear stretch (e.g. zoom half of what you would need to fill the screen and linear stretch the rest of the way), which I think is possible but not as good as the Pioneer "wide" mode (IMO).


Alternatively, it is entirely possible that Mike and I didn't understand each other when I asked him about this and that you are right (as you usually are about these things!).
 

·
Registered
Joined
·
1,284 Posts
Doesn't the "wide" mode on the Pioneer produce a fishbowl effect? Especially when images are panned or the camera is moving, causing you to run for the barf bag?
 

·
Registered
Joined
·
61 Posts
Actually I think what asinshesq is saying makes a lot of sense. The Panasonic 42 Plasma has a very nice non-linear stretch and it was the lack of this feature that caused me to return one scaler. (Using the scaler to de-interlace disables the non-linear stretch) I'm surprised that someone doesn't do this, it's really the best way to watch 4:3 material on a plasma.
 

·
Registered
Joined
·
2,584 Posts
Discussion Starter · #6 ·
Quote:
Originally posted by lwang
Doesn't the "wide" mode on the Pioneer produce a fishbowl effect? Especially when images are panned or the camera is moving, causing you to run for the barf bag?
Yup, you're right...there's no question that wide mode introduces distortions -- how else could you fit the 4:3 square peg into the 16:9 round hole? But many people believe that for most 4:3 material the tradeoffs are far less in wide mode than in linear stretch. My own view is that there is no contest -- Pioneer's wide mode (Panny has a similar mode but I forget what it's called) is really quite good for most material while simple linear stretch looks absolutely awful.
 

·
Registered
Joined
·
9,884 Posts
I wrote a prototype for it in DScaler a few months ago and there didn't seem to be much interest so I never finished it. But I did implement it as a WarpedResize function of my SimpleResize filter for the open source Avisynth utility.


For instance, a 16:9 image warped to fit on a 4:3 screen:

www.trbarry.com/WarpTest.jpg


or a 4:3 image warped and stretched to fit on a 16:9 screen:

www.trbarry.com/Warptest2.jpg


- Tom
 

·
Registered
Joined
·
1,687 Posts
Tom


Dscaler already has a prototype strech filter in it which is maybe why yours didn't attract much interest, yours may well be better so I wouldn't shelve it just yet, could you post your code to the list or something.


John
 

·
Registered
Joined
·
25 Posts
Actually I had been looking at processors for my Panny 42" Plasma and it was this exact reason I didn't get one. I would love to get great de-interlacing for my Cable and ReplayTV's, but I won't give up my "Just" mode (thats the panny's term for Wide, I think it stands for justified, could be wrong). After you watch for a short amount of time, you can hardly tell there is some streching going on (unless there is a ticker or something running along the screen). I would be very interested in this feature on a good reasonably priced scaler (i.e. omega 1 or CS-1 price range).
 

·
Banned
Joined
·
1,400 Posts
Just got off the phone with Mike at KD. You are all correct, the only thing the custom aspect ratio's allow you to do is a linear stretch. The Leeza cannot do a non linear stretch and neither can any other external scaler on the market today. For the laymen: Non linear allows you to non uniformly stretch any part of the image seperate from other parts of the image. A linear stretch can only stretch the image uniformly, all together up and down and left and right, so you have equal distortion all around as opposed to distorted sides and normal center which is what most internal plasma scalers provide. He did say he would work on it though.
 

·
Registered
Joined
·
1,948 Posts
just to nit-pick at eric:


you can have a stretch without distortion. assuming it is linear and applied equally in the horizontal and vertical dimensions.


what most seem to want is to take an image which is not full width and stretch to full width. to not distort, you would have to also equally stretch the vertical, but then it would exceed the screen height. the work around is to only stretch the horizontal, but that "only" is what can produce the distortion. a workaround for that is to horizontally stretch the side 25% areas and leave the center alone (the non-linear horizontal stretch). the idea being faces in the middle won't look too fat, but the screen will still be filled. then you get the other wacky effects, like weirdly distorted yardline markers when at diagonal and the huge shoulder/tiny head effect, or wide body growth when a charachter moves from the center to the side.


nasty as it is with its cropping, i prefer the non-distorted h and v stretch where circles are round anywhere on the screen. i cannot deal with any of the distortions.
 

·
Registered
Joined
·
615 Posts
Quote:
Originally posted by ericbee
Just got off the phone with Mike at KD. You are all correct, the only thing the custom aspect ratio's allow you to do is a linear stretch. The Leeza cannot do a non linear stretch and neither can any other external scaler on the market today.
Vigatec Dune can do nonlinear stretch, although it's not called that in the menu. Works very well, and you can customize the amount of non-linearity, which makes it superior to the non-linear stretch modes that I've seen available in displays.
 

·
Registered
Joined
·
18 Posts
My Extron DVS 204 allows me to do non-linear sizing. It isn't called that in the controls, but it offers both independent vertical and horizontal sizing. I have 3 sizing settings on each input. It's actually really cool. When I have a DVD with a different ratio, i just press the input button a second time and "Pop" it pulls up another setting and fills the screen.
 

·
Registered
Joined
·
9,884 Posts
To stretch a 4:3 (12:9) ratio onto a 16:9 screen requires a 33% stretch. This is a lot but can be spread over 4 factors, each of which can each be made small enough to not annoy too many people.


1) Stretch the width toward the edges enough for a 7.5% overall horizontal stretch.


2) Crunch the vertical near the tops and bottoms enough for a 7.5% overall vertical squeeze.


3) Crop (overscan) the vertical 7.5% more than the horizontal. (just minimize horizontal overscan)


4) Let the aspect ratio even in the center still be 7.5% too wide.


But 1.075^4 = 1.335


For the software oriented folks there is source code at www.trbarry.com/SimpleResize.zip . That is what I used for the pics above though I don't think I cropped there.


- Tom
 

·
Registered
Joined
·
629 Posts
I have to agree with you all - I have a Leeza/503cmx combination and I wish I was able to use the "Wide" mode on the 503.


I think that this would be a fabulous upgrade to the Leeza!


David
 

·
Registered
Joined
·
18 Posts
I can take any image ratio 1.33, 1.77, 1.85 or 2.35 and fill my Princeton Graphics display without cutting off any active video. I think that is non-linear. There is more sizing and centering range than I need.


I'm running the output at 720p. I don't know if that makes a difference.
 

·
Registered
Joined
·
2,584 Posts
Discussion Starter · #20 ·
Ofer, I don't think there's anything non-linear about trbarry's suggestion, it just seems to spread linear impacts over more dimensions. I also suspect that the idea of stretching horizontally 7.5% and crunching vertically 7.5% (and then filling out the screen with enough overscan to do the job) is really no different mathematically than stretching more horizontally to begin with -- I suspect the end result is really a compromise where you stretch halfway and zoom the remainder (with half as much stretch and half as much crop as you would otherwise need to fill the screen). I still expect things would look too distorted for me in the middle, but it's worth playing with. Anyone played around enough with the custom a/r's to figure out how to make his idea work in practice? I tried to set up a combo of stretch zoom once before and the Leeza kept defaulting back to more 'proper' measuremetns that didn't work (it seemed to only allow me to zoom or do a full anamorphic stretch).
 
1 - 20 of 26 Posts
Status
Not open for further replies.
Top