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4:3 within a 16:9 screen - off topic

454 Views 18 Replies 7 Participants Last post by ChrisWiggles, Jan 23, 2004

mikecazzx

Discussion Starter · Jan 22, 2004

Rather than building a 4:3 screen I am wondering if there is a way to display a perfect 4:3 image within a 16:9 without squashing the picture vertically.

I intend to watch a fair amount of 4:3 but, I think a 16:9 screen will look better in the room.

Using an 8' wide screen as an example, would a 4:3 image in the center basically be about the size of a 53" RPTV?

If possible, how is this done and does it involve an HTPC tweak, CRT setup, or both? Can it be stored in memory in the HTPC and the CRT?

CRT: NEC XG100.

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1 - 19 of 19 Posts

doubleJ

· #2 · Jan 22, 2004

If you're running through a htpc and you have the htpc's resolution set for 16:9, it should be automaticly right. I'm doing it just fine with my x1 (dlp). My screen is 74" 16:9. Even though the x1 is 4:3 native, I couldn't stand the fact that crappy analog cable was bigger than my dvd movies.

JJ

mikecazzx

Discussion Starter · #3 · Jan 22, 2004

Quote:

Originally posted by doubleJ
If you're running through a htpc and you have the htpc's resolution set for 16:9, it should be automaticly right. I'm doing it just fine with my x1 (dlp). My screen is 74" 16:9. Even though the x1 is 4:3 native, I couldn't stand the fact that crappy analog cable was bigger than my dvd movies.

JJ

Such a simple concept has me confused.

If I have a 16:9 screen running a resolution of 1280x720 and I project onto a 16:9 screen with a 4:3 image, won't the image go off the top and bottom of the screen?

doubleJ

· #4 · Jan 22, 2004

Nope...

Not if you're using a htpc and the resolution is 16:9. I'm using 720x480, too. Would you like to see some really crappy screenshots ( http://www.anti-exe.com/theater/screenshots/ ) 0095 is 4:3 inside 16:9. It really is a simple concept (IE...It just works).

JJ

Edit...

720x480? What's wrong with me? I'm using 1280x720.

JJ

Matthew Todd

· #5 · Jan 22, 2004

Quote:

Using an 8' wide screen as an example, would a 4:3 image in the center basically be about the size of a 53" RPTV?

If possible, how is this done and does it involve an HTPC tweak, CRT setup, or both? Can it be stored in memory in the HTPC and the CRT?

Using an 8' wide 16:9 screen, a 4:3 image would have the same height (54") and a length of 72". It would be the same size as a 90" RPTV.

Just to give another example, I'm using an 84" wide 16:9 screen, and an HTPC running Theatertek DVD player. The HTPC feeds the projector a resolution (16:9) of 1280x720.

When I play a 4:3 DVD (say Casablanca) the image is automatically centered in the 16:9 screen. The software makes this change automatically.

doubleJ

· #6 · Jan 22, 2004

mikecazzx...

It's magic. Don't be fooled.

^O^

JJ

pwentz3l

· #7 · Jan 22, 2004

I want to contest the automatic statements. It is if you have your software set correctly. The good thing about TheaterTek and DScaler, is that you can force them to do things that mystify me as to why anyone would be interested in doing such a thing. e.g. you can force DScaler to stretch your 4:3 image to 16:9. If you have changed from the defaults on your software, it will not be automatic. Once you get the software set to the proper settings (very easy to do), it is magic!!

Doug Baisey

· #8 · Jan 22, 2004

Guys,

Glad to see Mike ask, Ill add NTSC to the question.

I cant keep up on the latest 'tricks'

On this subject has anyone tried using the Lumagen Vision scaler for this application.

Im starting on a project now and to save new tubes Im leaning towards scaling the 4:3 to fit the existing 16:9 screen which is quite large 104 X 58"

Its used mainly for DVD but will also be used for 20% sports via sat, upconversion now is being sent through a doubler but ran 4:3 format in the center and why the tubes are being replaced.

Rather then pulling it out of format what are you guys using now to scale the dreaded NTSC ?

Anyone using the Lumagen Vision or know how it looks for scaling / upconverting and keeping format.

Sat STB is a Echostar DV3, I dont think its an option to change that but maybe I can. Thanks in advance. Doug

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ChrisWiggles

· #9 · Jan 22, 2004

JJ: I thought you had a 16:9 digital projector? Your setup would be different.

Regardless, Mike: you need to do the anamorphic squeeze, and then set your computer up to a 16:9 ratio. This will get you a constant height setup on the 4:3 tube face. This is not ideal as for tube wear, as you are wearing a very small 4:3 area, WITHIN a 16:9 area, WITHIN a 4:3 tube face. However, it is a very cinematic setup, since the wider the aspect ratio, the wider/bigger the screen, instead of having to mask smaller with constant width. Hope that makes sense.

Some projectors do not have the range in vertical squeeze to do a complete anamorphic crush, thus need to be modified.

doubleJ

· #10 · Jan 22, 2004

ChrisWiggles...

I have a 4:3 projector, just like any of the crt folks. It's just that mine is dlp instead of crt. I don't see how mine would be done any differently than yours.

JJ

ChrisWiggles

· #11 · Jan 22, 2004

The difference is that there are two (main) ways to do your setup with a CRT:

you can do a constant width setup, where you use a 4:3 resolution on your computer to match the native 4:3 resolution of the CRT projector. Thus a 4:3 AR movie would be the largest picture you'd get. For widescreen 16:9 you'd mask down top and bottom, and for wider AR you'd mask down even further. This is a constant width setup.

You can also do a constant height setup, in which case your AR would likely be 2.35 of your screen. Then you'd mask in from the SIDES. To accomplish this, you'd set your computer to a resolution that would be quite wide to match the screen (you can use something in between like 16:9 and do other crazy things too). Displayed on a 4:3 device like a computer monitor or a CRT projector, everything would be insanely tall and skinny, and still in 4:3. Then you do a vertical image squeeze of the raster itself, which you cannot do on a digital projector (obviously there is no raster).

This brings the image down to a widescreen, correct geometry image.

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doubleJ

· #12 · Jan 22, 2004

ChrisWiggles...

Ok, I'm on an x1 (dlp) with a 16:9 screen and I'm using a resolution of 1280x720. When I set 1280x720 on the htpc and the x1 is on 4:3 mode it is vertically stretched, is that kind of what you're talking about? I then set the projector to 16:9 mode and everything is as it should be.

If I'm reading you correctly, it's the same premise, except that crts don't have a 16:9 mode. You have to use some external process known as "verticle image squeeze of the raster itself". Is this just a setting or some piece of hardware or what?

JJ

Sokoloff

· #13 · Jan 22, 2004

Quote:

Originally posted by Doug Baisey
Its used mainly for DVD but will also be used for 20% sports via sat, upconversion now is being sent through a doubler but ran 4:3 format in the center and why the tubes are being replaced.

Rather then pulling it out of format what are you guys using now to scale the dreaded NTSC ?

"Upconvert" using DScaler and either use "bounce" (to slowly move the 4:3 image back and forth inside the 16:9 scree) or non-linear stretch to stretch 4:3 to 16:9, but preserve the A.R. of the center of the screen more than the edges. It sounds weird, but it works pretty well in practice for most "talking heads" type of shows (less so for auto-racing...

)

---Jim

ChrisWiggles

· #14 · Jan 22, 2004

Yes JJ, you manually crush the V size of the raster through pot adjustments on a CRT projector to achieve correct geometry for anamorphic 4:3. You use a circle pattern to ascertain when you've gotten the correct amount of smush. "Smush" is the professional, technical term for this. jk

Doug Baisey

· #15 · Jan 22, 2004

Jim,

Using a HTPC isnt an option in this application.

Chris,

'Smush'

is added but cant be a global setting. Doug

mikecazzx

Discussion Starter · #16 · Jan 22, 2004

You guys lost me 5 posts ago.

I will sit this one out till my room is done and the projector is up and running, but thanks for now.

ChrisWiggles

· #17 · Jan 23, 2004

I don't understand your comment about it "can't be a global setting?"

I'm running 4:3, but it was my understanding that it very much was a global setting if you run squeeze mode, as the raster v height is global, correct?

Anyway, here are a couple good threads for reading that i came up with:

http://www.avsforum.com/avs-vb/showt...orphic+squeeze

http://www.avsforum.com/avs-vb/showt...orphic+squeeze

Doug Baisey

· #18 · Jan 23, 2004

Chris,

On this one there are more the two inputs, if you change the V size pot it affects all inputs on most projectors (global).

The XG V size is menu driven for each input. I was more interested in keeping the correct format and scaling of the NTSC source where the 4:3 image stays centered and the outside edges scale like 'stadium' mode on the plasmas.

The Lumagen uses 1080I and 720P I believe but was thinking 720P to high for a decent upconversion of NTSC. I havent seen the Lumagen Vision in action or if the scaling cuts information out where I need it, like baseball scores.

Mike,

I dont want to confuse you, I was asking more about NTSC upconversion and scaling. Thanks, Doug

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ChrisWiggles

· #19 · Jan 23, 2004

Oh, yes Doug, that's what my understanding was. A pot adjustment would definitely be a global adjustment.

I was intrigued if you could do it non-globally, then do some wackier setups or something.

1 - 19 of 19 Posts

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