Are tvs truely 16x9 or 4:3?

[broderp]

What I mean is this,

I have cable TV, 4:3 boadcast.

I've had a problem with 480i windows desktop fitting correctly on my TV screen, and have never gotten powerstrip to fix this problem.

Anyways, I don't think this is a powerstrip isuue.

I want to get the FULL SAGE 4:3 picture on my 4:3 screen with little overscan. I have a 53" SONY TV.

I'm using the ASPECT RATIO SETTINGS in the advanced menu, and started both HOR. and VERT. stretch at 50%. This puts a small picture in the center of the screen. I gradually increase both the same amount to maintain the aspect ratio. I use offest as I go along to maintain a centered picture. (Only used it once).

Here is he problem, when I get to 92% stretch (H & V) I've just about filled the screen VERTICALLY. I set them both to 95% to give me just a bit of overscan and it looks good VERTICALLY.

However at 95%, HORIZONTAL still has a decent amount of "black" bars on the right and left.

If I raise the Horizontal stretch to 98% or 100% to cover the black bars, then I mess up my aspect ratio. If I raise the Vertical to match, then I get more overscan than I want on the vertical aspect.


Why is this? Obviously I will have to overcompensate the VRTICAL and have more overscan than I want, but is it because my screen isn't a true 4:3 or the cable company is not broadcasting in a true 4:3 aspect ratio??

[stanger89]

Well the AR thing is a tricky one, especially when you throw PCs into the mix. On a PC there are really two ARs to consider, the physical AR of the display, and the Pixel AR of the resolution you're running. Pixels aren't always square.

For example, say you've got a 16x9 plasma with a resolution of 1024x768 (they exist). You'll notice that the physical AR of the plasma is 16x9, while the Pixes AR is 4x3. The problem is all AR calculations (in Sage and many other apps) assume square pixels. So, for example, in this situation if you were using the 4x3 AR for 4x3 content it would be stretched 16x9 by the display.

What I'm saying is if you have a 4x3 TV, and are adjusting for 4x3 content, don't worry about whether the AR settings are the same for H and V, make it fill the screen like you think it should.

One more thing, due to the way Powerstrip and your TV out work PS won't help with adjusting the TV-out, you'll need to use the TV-out settings in your drivers to adjust that. If you've got an nVidia card, TV Tool might help you also.

-edit, never mind, you're not using your TV out are you? What resolution are you running?

[mls]

480i should be a 720 x 480 resolution (or same as a DVD player connected to S-video or composite).

However, since you have a 9600, I'll assume your using some DVI out adaptor to connect to the TV (which may, or may not be compatible with your TV). And/or the Transcoder further confusing things.

Either way, I'm not sure what you are trying to do. Almost sounds like you're trying to make a 4:3 picture fill a 16:9 screen area.

Not knowing all the specs for your TV and it's in/out cababilities and/or native resolution...

I'd say first put everything back to defaults and try upgrading to Catalyst 4.8. Then check the specs for the input resolutions for your TV (especialy native resolution) and work from there.

[broderp]

My PC is outputting 640x480i from my ATI 9600XT card that is plugged into my transcoder, then into my HD input on my TV.

My TV is a 4:3 HDREADY SONY with a 16x9 mode. (all scan lines are used in 16x9 area, no wasted lines on upper and lower black bars)
Assumming that the BROADCAST of cable and DVD on 4:3 material is indeed a true 4:3 aspect, and not just "close", it is very important that I keep the Horizontal and Vertical Stretch the same, unless some other factor is involved (pixel shape??)

If I dont, (using Video essentials with dvd player in sage) a ROUND shape is not truely ROUND, but oval. So they (H & V have to be the same.)

As I adjust them in size to fill my screen, I fill the VERTICAL (top to bottom) first, and still have space on the sides.

If I stretch the Horizontal to fit, without adjusting the Vertical (remember Vertical is perfect) then my static image on screen turns to oval.

Obviously I want to fill my 4:3 screen, so I have to also match up the Vertical to match the horizontal, hense gving me more overscan than I want on the vertical access.

So either my TV viewing area really isn't a true 4:3, or the broadcast cable isn't 4:3, or something else is at play..pixel shape and size??

Is is clearer now?

[stanger89]

Now that's puzzling... First a suggestion, try a higher resolution, you should be able to get 1280x1024i working, it runs in a 1080i timings. I assume you have powerstrip here's my timing parameters:

PowerStrip timing parameters:
1280x1024=1280,68,56,260,1024,43,3,55,56160,280

Generic timing details for 1280x1024:
HFP=68 HSW=56 HBP=260 kHz=34 VFP=43 VSW=3 VBP=55 Hz=30

Linux modeline parameters:
"1280x1024" 56.160 1280 1348 1404 1664 1024 1067 1070 1125 interlace +hsync +vsync

It should give you a better picture than 480i.

-edit

I should ask if the 16x9 mode is defeatable, ie how does it get invoked? Can you feed the TV an HD resolution and have it fill the screen, or is it forced to be letterboxed/squeazed?
-edit

First I assume that your TV is actually 4x3, but just in case, you could always measure it.

Second I know the pixel aspect ratio of recording is 3x2 (720x480), I'm not 100% sure if those are square pixels or not they may be .9, so that would make recordings 1.35:1. The best way to find out is to fire up DVE, put up a 1.33:1 test pattern get out the tape measure and set the zooms so it fills the screen and is square (video background works really good for this)

Now for the tricky bits, you've got a 1.33:1 TV, 1.5:1 (pixel ratio) source, so what you should get with equal zoom settings is bars top and bottom. So from there I must ask, which AR mode are you using. Fill, 4x3, and 16x9 do not maintain the original AR, however Source does. With the exception of fill, all calculate the output AR based on your screen resolution, assuming square pixels.

[broderp]

I'd love to use a higher resolution, but a 1080i resolution will force my set in to it's HDMODE, or 16x9 mode.

This is the equivelent of about a 48" 16x9 TV, on my 53" 4:3 set. Since my material is cable, and is usually 4:3, thiswould be like watching a 30" 4:3 centered in my 53" big screen. Thats not acceptable.

I have an old copy (DVD) of video essentials for my references.


Hmm..I'm using 4:3, let me try source...

[stanger89]

Just curious, does 480p kick you into HDMODE also?

[broderp]

Originally posted by stanger89
Just curious, does 480p kick you into HDMODE also?

NO, but on this SONY, all 480i inputs get upconverted to 960i, which looks better for video, especially DVD IMO.

If I could find a way to disable the squeeze function with 1080i input, I'd have it made.

[stanger89]

Hey, it just occured to me, since 480p doesn't force HDMODE, have you tried driving it with a 960i resolution? Something like 1280x960i.

And wouldn't you know it, karnis just so happens to have powerstrip timings for 960i:

PowerStrip timing parameters:
1280x960i=1280,128,96,160,960,44,1,120,56160,280

Generic timing details for 1280x960:
HFP=128 HSW=96 HBP=160 kHz=34 VFP=44 VSW=1 VBP=120 Hz=30
interlace +hsync +vsync

He's got a buch of PS timings in his guide:
http://www.avsforum.com/avs-vb/showt...hreadid=206854

- Edit, upon closer inspection, that particular timing is 1080i based, but you should be able to build one 480p based.

-edit2, what you're going to want to go for is something with 30Hz refresh (interlaced) and 31.5kHz scan rate.

[broderp]

SHOULD BE ABLE TO is the operative word....unfortunately, I have had a hard time figuring out PS mainly because MOST examples I've seen work on TV's other than mine. When NONE of the examples (ok a few have, like the 480i I found) work, it's difficult to make heads or tails of a concept as those of "front porch, back porch etc...into focus.

[stanger89]

Where to start...

Basically when feeding an analog TV, there's one important value that the TV uses to determine what to do. That value is horizontal scan rate, and it's determined by the refresh rate and the number of lines scanned.

Now there's another important thing to know, and that is that more lines are sent to the TV than just those that are actually used. For example with 480p, there are 480 active lines, however the signal set to the TV actually has 525 lines.

So for 480p the horizontal scan rate is 525*60 = 31.5kHz.

Now in simple terms Porches are just the areas that don't contain active pixels. For example with 480p, in vertical geometry, 480 (active lines) + Front Porch + Back Porch + Sync Width = 525. It's similar with the Horizontal

I'm not entirely sure, but I'd guess PS has a 960i resolution include that would probably be a good starting point.

[mls]

I guess I just don't follow what's being tried to accomplish here with all the xtra resolution changes and out thru a trasncoder?

Since the MPEG enocded files from SageTV would only be standard def 4:3 NTSC (480i), and your TV is supposedly 4:3...

Then one would think the most logical way to connect it would be via the S-video out of the ATI AIW 9600.

That way everything stays at 480i and the TV should do whatever it automatically does with any other standard 4:3 input source.

Seems like a lot of extra work trying to reverse engineer what the TV would automatically do by itself backwords thru the transcoder and vid card to come up with something compatible.

Plus, I can't see where all that extra reprocessing combined would do much of anything other than further reduce the picture quality.

Am I missing something in what you are trying to accomplish here?

[stanger89]

Originally posted by mls
Then one would think the most logical way to connect it would be via the S-video out of the ATI AIW 9600.

It's not that easy, just look at all the threads about the PVR 350 vs video card TV-out. It's especially bad with an HDTV since the video will be deinterlaced by the decoder, interlaced by the TV out, then deinterlaced again in the TV. On our Mits, that resulted in a wierd background going in and out of focus thing (hard to explain).

Driving an HDTV at HD resolution via VGA/DVI/Component will result in much better PQ than via S-Video.

[mls]

Originally posted by stanger89

Driving an HDTV at HD resolution via VGA/DVI/Component will result in much better PQ than via S-Video.

While that may be true for a real 16:9 HDTV, the prob here is that his tv is 4:3 (claiming to be "HD ready").

I looked up the manual for it before and it will not accept 720p input at all. It has a digital in for 1080i (which is the manual says is not designed to work with computer input... that must be why he's trying to use a transcoder).

Otherwise it will accept 480p and 480i.

For any 16:9 input it can be changed to letterbox it to fit in the 4:3 screen (black bars top/bottom).

The 1080i DTV input must be going thru an internal transcoder to convert back down to 480.

In otherwords, it would appear it's native resolution is 480 and everythings is down converted to that anyway. So, that's why I don't see any logic to most of what's been mentioned here so far.

Only thing I didn't spot (yet) in the manual is if it's "native" mode is 480i or 480p. If it's 480i, then S-video or Component in would be the better choices (rather than all the funky upconverting and then coming back to 480 internally).

If it's native mode is 480p (which I somehow doubt), then maybe Component instead of S-video might work better.

Either way, his vid card can output those and there really shouldn't be a need for the transcoder.

Much simpler all the way around to just work with the native resolution of the TV (since everything else would end up being converted back to that anyway).

It's seems to be a rather weird tv. Almost seems to be nothing more than a fancy 4:3 standard def tv with built in downconverter for a DTV receiver.

Follow what I mean now?

[stanger89]

Originally posted by mls
While that may be true for a real 16:9 HDTV, the prob here is that his tv is 4:3 (claiming to be "HD ready").

The AR of the TV makes little difference, mine is a 4:3 HD-ready and it works just fine at 1280x1024i, but mine doesn't squeaze.

I looked up the manual for it before and it will not accept 720p input at all. It has a digital in for 1080i (which is the manual says is not designed to work with computer input... that must be why he's trying to use a transcoder).

Many CRT HDTVs don't accept 720p, and most can't display it. He's using a transcoder I'm sure since it only has component ins. FWIW, nearly all TVs, even if they have computer (VGA/DVI) inputs, say they aren't designed to work with a computer. The truth is, they have no way of knowing if it's a PC or not, it just means it probably won't be plug and play like a monitor.

Otherwise it will accept 480p and 480i.

And probably 960i since it has the exact same scanrate as 480p.

For any 16:9 input it can be changed to letterbox it to fit in the 4:3 screen (black bars top/bottom).

The 1080i DTV input must be going thru an internal transcoder to convert back down to 480.

I doubt it, he already said that 480p is converted to 960i, and that 1080i goes into squeeze mode, so I assume it's a standard HDTV in that it supports up to 1080i scan rate.

In otherwords, it would appear it's native resolution is 480 and everythings is down converted to that anyway. So, that's why I don't see any logic to most of what's been mentioned here so far.

CRTs have no native resolution, the closest thing they have is a maximum scan rate, and if it can display 1080i it's max scan rate must be at least 33.75kHz, 480p and 960i are both 31.5kHz scan rate and should be

FWIW, most CRTs don't support 720p because of it's very high scan rate - 45kHz.

Only thing I didn't spot (yet) in the manual is if it's "native" mode is 480i or 480p. If it's 480i, then S-video or Component in would be the better choices (rather than all the funky upconverting and then coming back to 480 internally).

If it's native mode is 480p (which I somehow doubt), then maybe Component instead of S-video might work better.

Either way, his vid card can output those and there really shouldn't be a need for the transcoder.

Most video cards don't offer component output, that's why the transcoder is needed.

Much simpler all the way around to just work with the native resolution of the TV (since everything else would end up being converted back to that anyway).

Like I said, that's not really possible since CRTs have no native resolution, instead on a CRT, you aim to run at it's highest supported scan rate, which would be 33.75kHz, however that forces squeeze mode, so the next best choice would be 31.5kHz which would lead to either 480p or 960i.

It's seems to be a rather weird tv. Almost seems to be nothing more than a fancy 4:3 standard def tv with built in downconverter for a DTV receiver.

I dissagree, it sounds like a rather high-end 4:3 HDTV, which tends to cause problems, most notably, forcing a squeeze mode on 1080i signals. AFIAK, most of the "better" 4:3 HDTV work this way.

Follow what I mean now?

[stanger89]

broderp,

FWIW, here's the Keoki Powerstrip guide, it should get you started on a 960i resolution. You'll probably want to hook up a standard monitor first (or cloned) so you can see what your doing.

[mls]

Will be interesting to see if it will accept 960i input.

BTW: I must have missed something about the Keoki Powerstrip guide. Or was that link somewhere else?

[stanger89]

I sent it telepathically, apparently you don't have that plugin yet

http://www.keohi.com/keohihdtv/exper...uperguide.html

[mls]

Originally posted by stanger89

FWIW, most CRTs don't support 720p because of it's very high scan rate - 45kHz.

Guess we differ in opinions on what "HDTV" and "HD Ready" may mean. I don't consider anything that doesn't support 720p as HDTV (actaully an HDTV should support 1080p). However, in this case its an "HD Ready" tv (which really doesn't have much exact meaning when you think about it).

Most video cards don't offer component output, that's why the transcoder is needed.

True, but ATI does have a DVI-Component adaptor which would have been less espensive than a transcoder.

I'm just trying to understand why we're taking the long complicated way around when it appears there should be an easier (and less expensive) way of accomplishing the same thing?

[stanger89]

Originally posted by mls
Guess we differ in opinions on what "HDTV" and "HD Ready" may mean. I don't consider anything that doesn't support 720p as HDTV (actaully an HDTV should support 1080p). However, in this case its an "HD Ready" tv (which really doesn't have much exact meaning when you think about it).

The general consensus is that to be considered an HDTV, the display has to be able to do 1080i or 720p. HD Ready generally means no integrated ATSC tuner, and HDTV or Integrated HDTV meaning it has a tuner.

Most displays can't currently do both 1080i and 720p. Most digitals (meaning LCD, DLP, LCoS, plasmas) are 720p native (not enough pixels for 1080i), and most CRTs are max 1080i.

Granted there are a few 1080p digitals, and a few CRTs that can go to 45kHz for 720p but they are far from the norm yet.

True, but ATI does have a DVI-Component adaptor which would have been less espensive than a transcoder.

Yes, but he already has the transcoder. Plus the dongle severely limits your resolution options, it only supports 480i, 480p, 720p, 1080i, and a very limited set of variations on those.

I'm just trying to understand why we're taking the long complicated way around when it appears there should be an easier (and less expensive) way of accomplishing the same thing?

FWIW, I'm a firm believer in running the highest scan rate you can (for CRTs) or the native resolution (for digitals) to minimize the number of places the video is messed with. And since PCs are horrible at outputting 480i (probably even via component) I advise running at least 480p, and 720p, 960i, or 1080i if possible.