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Bars, Bars and More Bars

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Old 02-04-2005, 10:06 AM   #1
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Default Bars, Bars and More Bars

The first thing I get ask when the new 16:9 HDTV is fired up is, “How do I get rid of those gray bars?” Every new owner of a HDTV has considerable confusion about the pillar boxes that show up when SD 4:3 material is tuned in.

Why Bars?
The original television tubes were round and it would have been very difficult to be able to show a wide screen format on them. Square would have been the best as far as the tube goes, but there have been studies that when we humans watch a square for any length of time we get very tired, so the 4:3 format was adopted. So now along comes HDTV and in addition to greatly improving the picture, they decided to make it 16:9 widescreen as well to emulate the movie experience. Obviously, if you take a 4:3 SD picture and try to show it on a 16:9 widescreen, it will not fit. Enter pillar boxes, or vertical bars on the left and right of the screen.

Why Gray Bars and Sometime Black Bars?
Plain and simple the gray bars are used by the TV manufacturers to reduce the phosphor aging difference between the SD picture and the pillar box areas of the screen. If the pillar box areas of the screen were left black, the phosphors would not age as fast in those areas as the picture area would. Using the gray pillar box areas will cause the phosphors to age roughly the same as the picture area.

So why sometimes are there black bars? The black bars are added by the broadcasters for the 16:9 sub-channels. Once a sub-channel is formatted for 16:9 HD material, they will not switch the format. They just merge the 4:3 SD video into the black 16:9 frame. They could switch formats between the SD format of 480p and the HD format of 720p or 1080i, but that will cause most TV to blink and stutter while they resync to the new format, so they don’t switch formats back and forth. So why don’t the broadcasters use gray pillar boxes, you ask. Because black is the natural no video state and to use gray pillar boxes would require a video generator and quite frankly, they are not worried about your phosphor aging. Some broadcasters, like ESPN and our local FOX station, have added video generators to put their logo in plce of the black bars.

How Do I Get Rid Of The Bars?
When I was looking at this set in the store, I didn’t see any bars, how did they do that? Another study made early on in the adoption of TV was that the vast majority of people do not like to see blank spaces on a TV screen. This is why overscan was adopted by the TV manufacturers from the very first sets. Early on the problem was two fold. Not only were the tubes round, but they were not very accurate out at the edges of the CRTs. By starting the scan a ways beyond the edges of the screen, the edge of the screen that was visible would have less distortion. Bottom line is for decades, we have been conditioned for a TV picture to fill up the screen and we find it annoying if it does not. So enter the zoom and stretch modes to allow the picture to be manipulated to fill the screen. Just a note on this subject, the need for the picture to fill our screens is somewhat unique to TVs as we all seem ok with our computer monitors being adjusted just shy of filling the screen.

To accommodate this need the TV manufacturers have incorporated various methods to manipulate the picture to fill the screen. The electronics to manipulate the video was developed before the HDTV even existed for the early SD widescreen TVs that were for viewing widescreen DVDs, so they will only manipulate SD video. Only a very few HDTVs have any ability to manipulate HD video.

There is the 16:9 mode where the 4:3 SD picture is just stretched horizontally to fill the screen. If the original video is 4:3 material, then everybody on the screen looks very fat. This mode is best suited for widescreen video that was recorded on a VCR from a 16:9 source or viewing an older DVD player through s-video or composite inputs.

There is the Cinema mode where the picture is stretched vertically a small amount and the horizontal stretch is more near the edges than it is in the center of the screen. Tuning into the news channels where they have the crawl at the bottom of the screen will demonstrate this effect very well as the letters of a word will start fat on the left of the screen, gradually shrink to normal size in the middle of the screen and then get fat again as they disappear off the right of the screen. Different manufacturers have different names for this mode, but most all brands have some version of this mode as it is the favored mode for the stores to show SD material, because until you watch for a while it is hard to detect the stretch unless there is a crawl on the screen. Actually, they try their best to only show you HD or Finding Nemo because it shows the TV the best. I have said many times, it is best to audition your prospective HDTV on SD material and get the one that looks the best on SD. The HD will just be all that much better.

The last video mode many manufacturers provide is the zooms. Some provide a zoom that will stretch the screen horizontally to fill the screen and the vertical not quite as much, so while not keeping circles exactly round, the screen is filled without the Cinema effect. Sometimes the TV will have the ability to shift the visible part of the picture up and down. Full zoom where the screen is stretched equally in both directions and the top and bottom of the screen is cropped.

As I said before, the video processors for manipulating the video was developed for SD video. Since most HD video is 16:9 widescreen and will therefore fill the screen, most manufacturers do not provide any video manipulation for the HD video as it would require another video processor. So if you are viewing SD video that the broadcaster has inserted in a black 16:9 frame, you will not be able to stretch it like you could if you were viewing a SD input.

Letterboxed Movies and Shows
Another source for black bars is the letterboxed movies and commercials. More and more commercials are being shot in widescreen and even some shows are shown letterboxed when broadcast in SD. An example is American Chopper on the Discovery Channel. It is shot in HD widescreen for their HD channel, but is shown in letterbox on their SD channel. On a 4:3 TV the image will have black bars at the top and the bottom. If this image is merged into a 16:9 frame, you will end up with black bars all around the picture.

In the case of a letterboxed movie on DVD any number of strange occurances can occur. If the DVD is formatted for widescreen then there will be letterbox bars top and bottom, but people will look correct. If however the DVD is formatted for full screen (4:3) there will still be letterbox bars top and bottom, but people will look fat.

Tip for viewing SD video
If you want to view stretched video when the broadcaster has opted for black pillar boxes, you might consider hooking up a SD connection, either s-video, composite video or even the RF output to your TV in addition to the HD connections. Then you can select the SD input on the TV when you want to stretch the picture and return to the HD input when HD is being viewed. I know this is a bit of pain, but if you had bought a more expensive TV that allowed HD zooming…. Well that’s the trade off. Some cable and satellite boxes allow for stretching and zooming of the video and that might work for you as well.

Last edited by rbinck; 07-27-2005 at 03:05 PM. Reason: Letterbox info added.
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Old 02-04-2005, 04:31 PM   #2
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good stuff rbink, this should answer a lot of the recent questions on here regarding black bars. I'm sure you made someone's day!
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Old 02-18-2005, 10:57 AM   #3
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Excellent. Two questions:

1. I recently turned off digital / cable HD service. Now running analog cable thru a Tivo 2 in addition to my HD OTA tuner.

Thus, I'm once again concerned about SD PQ and bars when using the Tivo for non-local channels or recorded material.

I'm tempted to use 4:3 aspect setting more frequently on SD Tivo (vs. "stretch / cinema" setting) in order to minimize PQ deterioration. Thus, should I select one of the 3 grey sidebar options (bright, med, dark) on my Pany 42PWD plasma vs. the "off" option (all black)? Is the grey mode sufficiently effective to avoid burn-in?

Such viewing would not be 100% of the time, which is limited to evenings & weekends. If a good HD program is live on OTA, it gets viewing priority.

I realize this is a subjective question but I wanted to confirm my understanding of the purpose of grey bars with respect to moderate use on plasmas.

2. Can the top/bottom bars on 2.35:1 DVD's cause burn-in on the plasma? Somewhere, I had read that such bars were not problematic, but did not understand the logic for that conclusion.
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Old 02-23-2005, 10:55 AM   #4
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The gray bars will cause the pixels in those areas to age faster than the black bars would. I think the medium gray would be where I would start.

I think the issue with the letterbox black bars is there will be even more limited viewing of DVD letterboxed movies than SD viewing, unless you are a certified movie nut!
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Old 02-23-2005, 11:25 AM   #5
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Thanks alot. Sounds like it is ok to drink; I just need to do so in moderation!
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Old 03-08-2005, 01:51 PM   #6
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I think I'll chime in here. I'm a new hdtv plasma owner. I've learned alot on this site. thanks

Anyways, my plasma has a 'wide' or 'Full' (can't remember witch)setting and when I get black bars in viewing SD material, I set it to one of these settings and the bars are removed and the picture looks great (my sd comes in 480p). One of these setting do make people fat but the other does not. For HD, I only have 2 settings full and wide. Full will remove any black bars from some HD channels but the wide will not. Then the zoom which I don't use.

Gosh, you know I love technology but sometimes it can make life more difficult. Sometimes you just want to sit down, turn the TV on and forget about burn in, zoom, hd, sd , burning bars, wide, full, ISF cal, is it in 480i or 480p or 1080i or is there a 1080p yet? Cable box set up right? I wonder if I can get 720p. What about a splitter? ... no might hurt the signal. DVD in 480i! darn I don't have progressive scan. Is this an hd channel? no wait it's sd ... whew I thought my plasma was broken. why is there a buzz sound, is it the fan? I'm at sea level, must be the fan. HDMI to DVI, no I'll use component but wait they say DVI is better. It can drive you mad, ha ha ho ho he he, they're coming to take me away! Hold on, I'm going to the kitchen to watch TV on the 13" CRT on the counter.

Just a little humor .
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Old 03-08-2005, 05:56 PM   #7
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Quote:
Originally Posted by cannonball
I think I'll chime in here. I'm a new hdtv plasma owner. I've learned alot on this site. thanks

Anyways, my plasma has a 'wide' or 'Full' (can't remember witch)setting and when I get black bars in viewing SD material, I set it to one of these settings and the bars are removed and the picture looks great (my sd comes in 480p). One of these setting do make people fat but the other does not. For HD, I only have 2 settings full and wide. Full will remove any black bars from some HD channels but the wide will not. Then the zoom which I don't use.

Gosh, you know I love technology but sometimes it can make life more difficult. Sometimes you just want to sit down, turn the TV on and forget about burn in, zoom, hd, sd , burning bars, wide, full, ISF cal, is it in 480i or 480p or 1080i or is there a 1080p yet? Cable box set up right? I wonder if I can get 720p. What about a splitter? ... no might hurt the signal. DVD in 480i! darn I don't have progressive scan. Is this an hd channel? no wait it's sd ... whew I thought my plasma was broken. why is there a buzz sound, is it the fan? I'm at sea level, must be the fan. HDMI to DVI, no I'll use component but wait they say DVI is better. It can drive you mad, ha ha ho ho he he, they're coming to take me away! Hold on, I'm going to the kitchen to watch TV on the 13" CRT on the counter.

Just a little humor .
Cannonball
That is hilarious
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Old 03-15-2005, 07:55 PM   #8
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I am beginning to understand about this bar stuff but I still have a concern. Should not the vertical bars be symetrical? On my new set (rear proj.) I have the bars, both those broadcasted and the grey ones the TV provides, but they are not the same width on both sides of the picture. This seems strange to me. Is this to be expected or am I experiencing some kind of alignment problem?
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Old 03-16-2005, 11:50 AM   #9
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I haven't had that problem. See if your monitor has an adjustment for the position of the picture (vertical / horizontal adjustments); if so, is it centered?
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Old 03-16-2005, 07:27 PM   #10
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Just a bit of follow up.

Talked to Misubishi tech #1.....in short the response was that's the way it is just get used to it.

24 hours passes

Talked to Misubishi tech #2.....in short the response was that's not the way it should be call a service tech, it's still under warranty.

I have called the service tech to schedule a service call and we'll see what happens (wish me luck) . I'll post a result in case anyone is interested.
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Old 03-16-2005, 08:12 PM   #11
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Thumbs up I agree with jdmlsvtec -- this was hilarious!

Quote:
Originally Posted by cannonball
I think I'll chime in here. I'm a new hdtv plasma owner. I've learned alot on this site. thanks

Anyways, my plasma has a 'wide' or 'Full' (can't remember witch)setting and when I get black bars in viewing SD material, I set it to one of these settings and the bars are removed and the picture looks great (my sd comes in 480p). One of these setting do make people fat but the other does not. For HD, I only have 2 settings full and wide. Full will remove any black bars from some HD channels but the wide will not. Then the zoom which I don't use.

Gosh, you know I love technology but sometimes it can make life more difficult. Sometimes you just want to sit down, turn the TV on and forget about burn in, zoom, hd, sd , burning bars, wide, full, ISF cal, is it in 480i or 480p or 1080i or is there a 1080p yet? Cable box set up right? I wonder if I can get 720p. What about a splitter? ... no might hurt the signal. DVD in 480i! darn I don't have progressive scan. Is this an hd channel? no wait it's sd ... whew I thought my plasma was broken. why is there a buzz sound, is it the fan? I'm at sea level, must be the fan. HDMI to DVI, no I'll use component but wait they say DVI is better. It can drive you mad, ha ha ho ho he he, they're coming to take me away! Hold on, I'm going to the kitchen to watch TV on the 13" CRT on the counter.

Just a little humor .
Cannonball
As soon as my boss gets back to work next Monday March 21st, I'm logging in to this post and making him read it. (He's Irish, so I obviously won't see him tomorrow the 17th or during his day of recouperation after the annual bender). This was hysterical!! As I was reading it, I could hear his voice. He still has the 4:3 analog 20 year old RCA, and prefers his movies in Black and White. I'm afraid that when they finally cut the analog signals in 2007 we better have an ambulence and paramedics nearby.....
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Old 03-17-2005, 10:26 AM   #12
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If cannonball wanted a TV where he didn't have to worry about burn in or distorting aspect ratios to keep his screen filled or PQ loss from cross conversion he should have bought a 1080p LCD display like the 45" AQUOS... virtually all his complaints are solved by it.
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Old 03-17-2005, 10:36 AM   #13
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Glad your getting some laughs.

I wouldn't say they were complaints and I didn't mean them that way, it's just alot information especially when it's new technology and info.. ... and I did think about the LCD, but the larger sizes were to costly ... and I wanted a 50" PLUS even if I did get the LCD, any techno nut would STILL be thinking about all kinds of things. LCD and Plasma have their pros and cons.
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Old 03-17-2005, 07:39 PM   #14
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Here is the follow up on the Mitsu and picture being off center.
posted here

I hope the link works. I didn't want to duplicate the post here.
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Old 03-17-2005, 09:48 PM   #15
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Thumbs up How'd you do that?

Quote:
Originally Posted by Oldgoat
Here is the follow up on the Mitsu and picture being off center.
posted here

I hope the link works. I didn't want to duplicate the post here.
To Goat from Cat:

How did you do that? I've been able to put in links to a web page, but I could never figure out how to reference another post in a different thread on this Forum without doing a copy and paste. Anyway, it worked. Good job!
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