Hi,

I've been using DVE to adjust the picture geometry of my widescreen plasma.

I've adjusted the horizontal and vertical size to achieve ‘zero’ overscan. However, even though the pattern ratio is for 1.78:1 the circle in the centre of the screen doesn't look truly round.

Why would that be? If I have adjusted the boarders of the horizontal and vertical to equal scan parameters.

Am I using the right pattern? Which pattern should I be using?

I'm using the SD DVE disc played in 'Progressive' mode.

Thanks

Check the settings in your disc player.

Thanks ‘GeorgeAB’

The output of the DVD player is set correctly. Images look fine; however the circle doesn’t look as circular as it should. The screen linearity is perfect and is set correctly to widescreen mode.

I have a ‘Burosch’ test DVD that gives me slightly different settings in the horizontal size compared to the ‘DVE’ disc.

I’m not sure how most other user’s set up the 1.78:1 scan ratios? To get a perfect circle I would have to underscan in the vertical plane, or overscan in the horizontal plane by quite a bit, which to me assumes that the test patterns may not be a true 1:78:1 ratio?

How do the patterns display on other users Flat panels? Do you get a perfect circle? Are the horizontal/vertical overscans equal? Maybe it’s just my perception of vision making the circle look imperfect? Or maybe, it’s a fault with my DVD player?

It's almost as if the image is slightly 'anamorphic'.

P.S.

Also trying to adjust the scan Height/width, on the Satellite box. Same issues here. As there are no test signals, I underscan the image until the outside of the image boarders start to show and then adjust until they just about disappear.

The output of the DVD player is set correctly. Images look fine; however the circle doesn’t look as circular as it should.
It might be an optical illusion. Measure it. Use a tape measure and check it vertically and horizontally.

There is nothing wrong with the geometry patterns on 'DVE.'

If you have a Panasonic plasma, make sure it's not in "just" mode.
The circles measure perfectly on the plasmas I calibrate unless they are in the wrong mode.

OK, I looked further into this.

The standard Sony defaults for vertical (Height) size and horizontal (Width) size is:

V= 0
H= 0

Quite a bit of overscan!

With the DVE disc they come to:

V= -20
H= -35

With the Bursoch disc the settings are:

V= -20
H= -20

Now I know some manufacturers can overscan the image quite a bit to take into account broadcast material, which when flipping through the satellite channels differ a lot, however manufacturers usually ensure that the image ratio is correct.

This would leave me to believe that the Burosch disc, with its 20/20 setting is correct in comparison to the DVE 35/20 setting which will obviously distort the image ratio.

On the DVE ‘Chapter 24: Safe Action, Safe Title’. I would normally underscan to the point of seeing the ’10 pixel count markers’ at the edge of the image. However, if adjusted for this the vertical size is fine on all program material, but the horizontal size seems too small leaving a black bar, of approx 0.5cm on each side. How do people in this forum set the geometry on their displays? Do you set the display to show the ’10 pixel count markers’?

Thanks

How do people in this forum set the geometry on their displays?

I would suggest to set the horizontal size/position first so you get no or very little overscan on the sides.
Bring up a round circle. Measure it. Use a tape measure and check the circle vertically and horizontally.
After you get it "round" with adjusting vertical size, you can use vertical position to place it in the middle of your screen.

Thanks fro the replies.

I have managed to get the 'Perfect circle'

I underscanned the vert/Horizt, using the DVE pattern. However the circles didn't look very round. However when viewing the 16:9 commentated patterns on 'Burosch' DVD, this confirmed a perfect circle.

I'm not sure why the DVE circle does not appear very round?

It's quite a lengthy procedure trying to get the size/shift correctly adjusted for HD TV, as the size and shift vary considerably with each channel. I've settled on compromise which ends up with a little Horizontal overscan on HD channels and a little horizontal underscan on SD channels.

How do people in this forum set the geometry on their displays?I use my own patterns for most stuff. DVE is good for alot of things, but the overscan tests on the SD 2003 Component edition of DVE are not always completely accurate. Many of the patterns seem to have originated as 486-line D1, and appear to be unevenly cropped to 480 lines during translation to the DVD format. That could be why you're getting a different reading with DVE.

The circle is not "circular" in DVE's overscan test because that pattern was probably designed originally for 4:3 TVs. To check for correct aspect ratio with DVE, use the 1.33 and 1.78 aspect ratio tests at Title 12/Chapters 18 & 19. Or you can use the AR tests in the THX Optimizer found in the extras on many THX-mastered DVDs. (The THX patterns could be slightly more accurate because of the cropping issue mentioned above on DVE.)

I'm not familiar with the Bursoch disc, but if you want more accurate overscan adjustment, you'll need a different tool than the SD 2003 Component edition of DVE. If you have a DVD burner and are adept at using programs like Photoshop, it isn't that difficult to make your own by simply making hash marks at the different percentages of image width and height on a 720x480 image. Here's an example I posted for someone else: 114446*

(*Simply burning the image to disc as a JPEG will not be reliable btw because many players scale or add borders when displaying still images. To do anything useful it must be properly converted to the DVD-Video format. Here's the discussion that prompted the above image.)

The circle is not "circular" in DVE's overscan test because that pattern was probably designed originally for 4:3 TVs.The confusion on this is understandable btw, because even though the overscan pattern at Title 12/Chapter 17 was clearly designed with 4:3 TVs in mind (as indicated in the DVE docs), it was apparently authored on the DVD for 16:9 display, and will not, for example, work with the player-based 4:3 pillarboxing on many current HDMI DVD players.

This would not have been a major concern for HDTV owners back when the program was originally produced in 2003 because there were no HDMI upconverting players at the time, and the pattern could be displayed in either 16:9 or 4:3 ratio using the zoom/stretch modes on their HDTVs. It was probably more confusing for SDTVs owners though because they'd have to reconfigure their DVD players into 16:9 mode whenever they wanted to check the overscan on their 4:3 TVs.

I've seen this before on my brother in laws setup, cheap tv, cheap dvd, etc... the DVD player had a setting to determine what it did with certain formatted content as far as pillarboxing, letterboxing, stretching, etc, but nothing I did there changed that image from the DVE disk... movies, in a variety of formats, looked fine, however... looking through the manual I found that the dvd player could override the user settings for aspect ratio in certain circumstances... presumably there's a flag it looked for... and at that point I explained it to my bro-in-law, and gave up... sorry I don't remember the make/model of the EUT, but you get the idea...

Including both a 4:3 and 16:9 overscan pattern probably would have made things a bit easier and less confusing.

If you have a newer 4:3 SDTV that vertically compresses the raster on 16:9 content, then you'll probably need to turn the V-compression off on the TV in order to get DVE's overscan pattern to fill the whole screen. (The DVD player also needs to be configured for 16:9, but that's the way it usually should be set for TVs with V-compression anyway). Just remember to re-enable the V-compression after you're done checking the overscan, so other 16:9 content displays correctly again.

If the V-compression can't be disabled on the TV, then you're probably out of luck because most DVD players will have no way to force the DVE overscan pattern to display full screen in their 4:3 modes.

Very interesting, ADU. Read the link to the DVD player aspect ratio discussion.

I think I’ve managed to get the DVD input set-up correctly.

However, I'm still a little unsure about my STB. I have set the STB to output 1080i. I tune into the HD channels and proceed with adjusting the geometry. I do this by underscanning in both the horizontal/vertical plane until the black boarders are visible. I then proceed to overscan to the point where the back boarders have just disappeared. When I then switch to the SD channels, black bars, of approx 0.5cm, appear on either side. The SD images are slightly distorted and can only be overcome by overscanning the horizontal until the black sidebars disappear.

The vertical scan is the same for both SD and HD.

How would one adjust the scan ratios on a STB box?

Thanks

I think a couple of the HD channels (HDNet and Mojo?) were broadcasting some test patterns. Not sure if they're still doing that, but might be worth investigating. You might try contacting your HD service provider to see if they have any suggestions along these lines as well.

Another way to go is an HD player, either Blu-ray or HDMI DVD player. If you have a BD player, you could probably rent (or buy) the high-def BD edition of DVE. (Maybe it has some improved patterns for these kinds of adjustments.) Or you could just use the players to upconvert the DVD patterns to HD. Settings won't always translate perfectly from one input/device to another, but it's probably better than nothing. I've been sort of keeping an eye on developments in BD players since last fall. But still trying to hold out for a good (but cheap) newer profile unit that's fanless, and has decent DVD upconversion. (Panasonic's BD-35 looked somewhat promising, but that unit still has a fan.)

If none of the above are doable, then working back from underscan settings as you've been doin may be the next best thing.

I'm sort of surprised by the level of control you've got on your plasma btw. Most plasma TVs I've seen only have basic AR controls, and not much facility for tweaking overscan beyond that. The Hitachi model I tested a couple years ago gave the option of either "justified"/0% overscan, or about 2.5% overscan for the HD inputs, for example. That seems a fairly common approach for the new 1080p models. But I wouldn't be surpised if some 720p/768p panels still offer no 0% mode. Is the overscan/sizing control on your TV adjustable for each input/signal, or is it more of a global/one-size-fits-all affair?

Also, if your display is still in it's "break-in period", I'd try to avoid black bars (either vertical or horizontal) as much as possible to keep burn-in/uneven wear of the phosphors to a minimum. The phosphors have their biggest drop in brightness when the panel is new, and that gradually begins to taper off over time.

I have set the STB to output 1080i.Sometimes that works well, and sometimes it's better to just pass things through as is and let the TV do the translation to it's native display mode. It just depends on the equipment involved, and which device has the better deinterlacing and scaling capabilities.

I try to use only 1080i on my older Sony CRT because, to put it bluntly, SD tends to look pretty crappy to me on this TV (though many would probably argue it's SD is still better than many "fixed pixel" displays). 1080i is also the tube's highest native display mode, and the motion quality is generally better on these CRTs when they're in the interlaced (1080i) display mode than in progessive (480p) display mode because of the type of phosphors used on the tube.

If the STB has an option to pass through the different broadcast signals at their original resolutions though, I'd give that a try, because every TV works a bit differently. (And flat panels certainly have some different mechanics than an older analog tube.)

Thanks again, ADU.

I have a 32inch Sony Plasma. It's pretty old now, maybe 4-5years. It allows fine tuning of the scan which is independent for each input. It's the only plasma I know of that allows full adjustment of the horizontal/vertical scan.

The native resolution is something like 864 lines.

It would be nice if there were some HD test cards. I'm using ‘freesat’. The only HD channels available are 'BBC HD', 'LUXE HD' and 'ITV HD'. To my knowledge they are presently not broadcasting any test card?