Non standard PBS aspect ratio - AVS Forum
Forum Jump: 
 9Likes
Reply
 
Thread Tools
post #1 of 152 Old 07-08-2014, 10:19 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Exclamation Non standard PBS aspect ratio

I've noticed many PBS programs now have black bars at the top and bottom even though I'm watching on a 9x16 (1:1.78) HD screen. It appears that PBS is using a 1:2 aspect ratio instead of the ATSC standard of 1:1.78.

I find this very annoying because HDTV was suppose to get rid of letter-boxing. Nor do I see any need for it because there is never anything important at the extreme sides of the picture. I'd much rather have the center of picture fill my screen so it's bigger and easier to see. Using my set's zoom feature is no solution since image quality degraded by having fewer vertical pixels.

Worse of all- they are even showing old 3:4 video that has been stretched and cropped to fit a 1:2 screen which means that useful picture information at the top and bottom was discarded. Why can't PBS use the correct ATSC standard like everyone else?
zoreo is offline  
Sponsored Links
Advertisement
 
post #2 of 152 Old 07-08-2014, 10:27 PM
AVS Special Member
 
Aleron Ives's Avatar
 
Join Date: Oct 2009
Posts: 2,819
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 314 Post(s)
Liked: 367
It seems pretty common for PBS to show 16:9 content windowboxed, because they seem to assume that most of their audience is people with 4:3 TVs who wouldn't understand anything about aspect ratios.
Aleron Ives is offline  
post #3 of 152 Old 07-09-2014, 04:47 AM
Senior Member
 
mscottc's Avatar
 
Join Date: Sep 2006
Posts: 216
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked: 30
Are these new shows or perhaps movies being shown in their original aspect ratio? I'd find it incredibly hard to believe that anyone would produce new material for TV in anything but 16x9.
mscottc is offline  
post #4 of 152 Old 07-09-2014, 05:51 AM
Advanced Member
 
Mark12547's Avatar
 
Join Date: Nov 2013
Location: Salem, Oregon, United States
Posts: 655
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 128
What shows have the wrong aspect ratio? And which PBS affiliate? And are you watching it over the air, or through a cable or satellite service? (And, if so, the name of it?)

I haven't noticed my local PBS affiliate (KOPB in Portland, OR) having any aspect ratio issues on their HD channel or their SD subchannel as received through Comcast Cable, but it could be we are watching different programs.

My very humble setup:
Man Cave:Vizio E500i-A1 "Smart TV" (50-in 1080p 120Hz LED/LCD, has Netflix app.), Blu-ray players (Sony BDP-S3100, old LG BD390), Roku (the original model: N1000), PC (Windows 7), Comcast Internet (25Mbps/5Mbps).
Bedroom:LG 32LV3400-UA TV (32-in 768p 60Hz LED/LCD), HD DVR (Motorola RNG200N), Xfinity Comcast cable (Digital Starter Package), DVD/VHS player.
Mark12547 is offline  
post #5 of 152 Old 07-09-2014, 07:56 AM
AVS Special Member
 
dougotte's Avatar
 
Join Date: Oct 2004
Location: Washington, DC
Posts: 2,291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked: 30
Quote:
Originally Posted by zoreo View Post
I find this very annoying because HDTV was suppose (sic) to get rid of letter-boxing.
This is news to me!
dougotte is offline  
post #6 of 152 Old 07-09-2014, 10:13 AM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Quote:
Originally Posted by Mark12547 View Post
What shows have the wrong aspect ratio? And which PBS affiliate? And are you watching it over the air, or through a cable or satellite service? (And, if so, the name of it?).
I'm watching OTA from WGCU in Ft.Myers, FL. Some of the shows are normal 9x16 and fill the screen vertically and horizontally as it should but an increasing number have this black bar at top and bottom.

What really drove me to complain was watching a Ken Burns series called "The War" about WW-II last night. This program had a lot of WW-II era newsreel film in it that I'm sure was made in 3:4 aspect- as nearly everything was in the 1940s- but it is stretched out full width of the screen and you can just tell by looking that the top and bottom is cropped. Sometimes you can't even see the tops of the person's head. No photographer would have made it that way.
zoreo is offline  
post #7 of 152 Old 07-09-2014, 10:36 AM
Advanced Member
 
Mark12547's Avatar
 
Join Date: Nov 2013
Location: Salem, Oregon, United States
Posts: 655
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 128
Quote:
Originally Posted by zoreo View Post
What really drove me to complain was watching a Ken Burns series called "The War" about WW-II last night. This program had a lot of WW-II era newsreel film in it that I'm sure was made in 3:4 aspect- as nearly everything was in the 1940s- but it is stretched out full width of the screen and you can just tell by looking that the top and bottom is cropped. Sometimes you can't even see the tops of the person's head. No photographer would have made it that way.
I noticed that Netflix has this available for streaming and on DVD. It would be interesting to see if the streams or DVDs show the same disregard for OAR as you saw from the station.

I had seen some documentaries on DVD and TV that would stretch or crop to match the overall aspect ratio of the documentary and disregard the OAR of the footage or photos they had included in the documentary. (CNN's The Sixties had done this, I noticed.) If Ken Burns had likewise disregarded the OAR of included material so the entire documentary would be the same aspect ratio (my money is on this), then the PBS station broadcasting the documentary would just broadcast what they have, distorted and cropped images and all. But it is sad that a director working for PBS would do this instead of using pillar bars or other filler content on the sides so original images could be preserved in their entirety.

But then 7 years ago there were fewer HDTVs, smaller average TV sizes, and fewer people who would tolerate pillar bars. But I am not that hopeful after seeing this year's The Sixties on CNN do some nasty cropping.

My very humble setup:
Man Cave:Vizio E500i-A1 "Smart TV" (50-in 1080p 120Hz LED/LCD, has Netflix app.), Blu-ray players (Sony BDP-S3100, old LG BD390), Roku (the original model: N1000), PC (Windows 7), Comcast Internet (25Mbps/5Mbps).
Bedroom:LG 32LV3400-UA TV (32-in 768p 60Hz LED/LCD), HD DVR (Motorola RNG200N), Xfinity Comcast cable (Digital Starter Package), DVD/VHS player.
Mark12547 is offline  
post #8 of 152 Old 07-09-2014, 12:26 PM
AVS Special Member
 
Brian Conrad's Avatar
 
Join Date: Jan 2001
Location: Martinez, CA, USA
Posts: 4,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 169 Post(s)
Liked: 147
Are these European produced shows? Some European productions like Utopia were done in "scope" or a 2:35:1 or 2:1 aspect ratio. That is a better canvas for some stories especially ones that have a lot of action. Get over it. We've had enough destruction of film aspect ratios from HBO's little "scientific survey" of asking their office staff about how they liked "scope" movies presented.
Brian Conrad is offline  
post #9 of 152 Old 07-09-2014, 02:44 PM
Advanced Member
 
Mark12547's Avatar
 
Join Date: Nov 2013
Location: Salem, Oregon, United States
Posts: 655
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 156 Post(s)
Liked: 128
Quote:
Originally Posted by zoreo View Post
I called the station and the lady I talk to said they show the programs just as they get them from PBS. I don't know if she knows what she's talking about but that's the explanation I got.
If the whole show is stretched or cropped, I would suspect the station and notify the station. If the show is correct overall but there are individual sections that are stretched or cropped, that's probably how the show got delivered to the station and would notify the producer or originating site, if known.

My very humble setup:
Man Cave:Vizio E500i-A1 "Smart TV" (50-in 1080p 120Hz LED/LCD, has Netflix app.), Blu-ray players (Sony BDP-S3100, old LG BD390), Roku (the original model: N1000), PC (Windows 7), Comcast Internet (25Mbps/5Mbps).
Bedroom:LG 32LV3400-UA TV (32-in 768p 60Hz LED/LCD), HD DVR (Motorola RNG200N), Xfinity Comcast cable (Digital Starter Package), DVD/VHS player.
Mark12547 is offline  
post #10 of 152 Old 07-09-2014, 03:04 PM
Member
 
agus0103's Avatar
 
Join Date: Oct 2010
Location: Brainerd, MN
Posts: 185
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 17
When you see the bars, are you watching the main 30.1 high definition subchannel of WGCU or one of the three standard definition subchannels? I see, according to Wikipedia, that WGCU offers World, Create, and the Florida Channel. All three of those services are provided to stations in a standard definition 4:3 feed. At least as far as Create and World are concerned, programming produced in 16:9 is shown windowboxed on the 4:3 feed (I believe The Florida Channel is a straight 4:3 production), which will result in black bars only on the top and bottom if your TV is set to stretch 4:3 content to fill a 16:9 frame.

In short, your only solution may be to change the aspect ratio setting to zoom on your TV or wait for PBS to start offering Create and World to stations in 16:9. They have been talking about doing this for at least a couple years now, but I don't know if there are any definite plans in the works.
agus0103 is offline  
post #11 of 152 Old 07-09-2014, 06:20 PM
Advanced Member
 
veedon's Avatar
 
Join Date: Nov 2010
Location: Raleigh,NC
Posts: 813
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 179 Post(s)
Liked: 54
Quote:
Originally Posted by zoreo View Post
I'm watching OTA from WGCU in Ft.Myers, FL. Some of the shows are normal 9x16 and fill the screen vertically and horizontally as it should but an increasing number have this black bar at top and bottom.

What really drove me to complain was watching a Ken Burns series called "The War" about WW-II last night. This program had a lot of WW-II era newsreel film in it that I'm sure was made in 3:4 aspect- as nearly everything was in the 1940s- but it is stretched out full width of the screen and you can just tell by looking that the top and bottom is cropped. Sometimes you can't even see the tops of the person's head. No photographer would have made it that way.
According to the "Shop PBS" web site, the resolution and aspect ratio for that documentary are as follows: Video: 1080i High Definition 1.85:1 (Originally shot on Super 16 Film)
veedon is offline  
post #12 of 152 Old 07-09-2014, 06:35 PM
AVS Special Member
 
wuther's Avatar
 
Join Date: Aug 2008
Posts: 1,437
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 33
Quote:
Originally Posted by zoreo View Post
I'm watching OTA from WGCU in Ft.Myers, FL. Some of the shows are normal 9x16 and fill the screen vertically and horizontally as it should but an increasing number have this black bar at top and bottom.
What shows are like that? Films? My local PBS broadcasts (and has from the start of HD) all HD in full HD and all SD in 4:3 SD meaning if a film they get is in widescreen SD it will have bars on all sides. No special upscalling for the SD widescreen just the same treatment the non-widescreen SD got.
Quote:
Originally Posted by zoreo View Post
What really drove me to complain was watching a Ken Burns series called "The War" about WW-II last night. This program had a lot of WW-II era newsreel film in it that I'm sure was made in 3:4 aspect- as nearly everything was in the 1940s- but it is stretched out full width of the screen and you can just tell by looking that the top and bottom is cropped. Sometimes you can't even see the tops of the person's head. No photographer would have made it that way.
Did the non-1940s parts have the same look? If not the cropped footage are Ken Burns' doing. Zooming and cropping 4:3 and 1:37.1 film footage to fit 16:9 is quite common in HD documentary production, there are lots of blu-ray documentaries that do it, in fact you would be hard press to find one not doing it and a lot of them are taking it from a SD video source which of course means they look really bad.

While I agree 1:37.1 and 4:3 video footage should be in the those formats, it is the production company's and or network's fault not the PBS station. In short you are barking up the wrong tree.
wuther is offline  
post #13 of 152 Old 07-09-2014, 09:03 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Well this is really weird. I have a number of sets scattered around the house. Most are not used much so I never compared them on WGCU but tonight I checked them all and I find that some sets display WGCU subs 2 & 3 drawn in on the sides as you would expect when a 9x16 picture is shown on a 480x720 SD channel but 3 sets show subs 2 & 3 full width as if they are 1920 pixel wide and there is no way to change the picture to 3:4 on these sets. All the sets show sub ch 4 correctly as 3:4. All I can figure is that there is something in WGCU' PSIP steam that makes some sets (generally older ones) think subs 2 & 3 are 1920 pixel wide even though they are 480x720 pictures. It will take someone who knows more about ATSC than me to explain this.
zoreo is offline  
post #14 of 152 Old 07-09-2014, 09:44 PM
Advanced Member
 
veedon's Avatar
 
Join Date: Nov 2010
Location: Raleigh,NC
Posts: 813
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 179 Post(s)
Liked: 54
Quote:
Originally Posted by zoreo View Post
Well this is really weird. I have a number of sets scattered around the house. Most are not used much so I never compared them on WGCU but tonight I checked them all and I find that some sets display WGCU subs 2 & 3 drawn in on the sides as you would expect when a 9x16 picture is shown on a 480x720 SD channel but 3 sets show subs 2 & 3 full width as if they are 1920 pixel wide and there is no way to change the picture to 3:4 on these sets. All the sets show sub ch 4 correctly as 3:4. All I can figure is that there is something in WGCU' PSIP steam that makes some sets (generally older ones) think subs 2 & 3 are 1920 pixel wide even though they are 480x720 pictures. It will take someone who knows more about ATSC than me to explain this.

It all seems very complicated when it comes to how stations handle SD on a screen that physically is 16:9. According to rabbitears.info , WGCU may be using a form of "widescreen SD".

http://www.rabbitears.info/oddsanden...request=widesd

What I don't understand about widescreen SD is how there can be so many different resolutions associated with that. There is some distinction, I think, between aspect ratios defined in terms of physical measurements (inches) and defined in terms of pixel counts. There is also something called anamorphism that basically involves deliberately distorting an image prior to transmission in such a way that it can be "undistorted" later on. This technique may somehow involve combining several square (or round) physical pixels into a single rectangular image element that acts like a single pixel, but my understanding of this is very imperfect.

Maybe somebody who has greater technical knowledge than I have can explain how a "4:3 SD" picture, which to me should always be 640x480 (in its natural or native resolution) can be turned into a 16:9 image (by a technique other than simply stretching), yet still have different pixel counts or resolutions that are nowhere near the 1920x1080 that I associate with "full HD". Even 720p HD is far more pixels (1280x720) than in the various implementations of "widescreen SD".

Last edited by veedon; 07-09-2014 at 09:58 PM.
veedon is offline  
post #15 of 152 Old 07-09-2014, 10:05 PM
AVS Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 6,255
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 93
@Zero

Please use the correct terminology for aspect ratios. It is WxH (W:H), not HxW as you are posting. What you are using results in the image being taller than the width.

It is 16:9, 4:3, 1.78:1, 1920x1080, 720x480 (SD non-square pixel), etc.

IMHO, I believe that you have your TVs set wrong. I'd have to be there and look at what you are doing to truly understand what is going on.

AFAIK, PBS does not produce shows in 2.35:1. All shows are produced in 16:9 for their main HD feed.

For us to see what you are seeing, take a digital photo of the screen and post it.

"What do you say Beckett. Wanna have a baby?" - Castle to Det. Beckett
"How Long have I been gone?" Alexis after arriving home and seeing Castle and Beckett w/ the baby - Castle - 11/25/13
Mr. Video
My Geek Images

mrvideo is offline  
post #16 of 152 Old 07-09-2014, 10:18 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
veedon: Well all digital TVs have the ability to stretch video- like you can set a 4:3 picture to fill the width of a 16x9 screen. It doesn't make it more pixels- it just makes the existing pixels stretch out more.

What has me confused is the fact my set shows these subchannels the full width of the screen when they should be a 16x9 picture within a 4x3 frame like they are on all other SD channels except these two.

-----------------

OK mrvideo- I have reversed the aspect numbers although having the smaller number first seems more natural to me.

Last edited by zoreo; 07-09-2014 at 10:38 PM. Reason: To make mrvideo happy
zoreo is offline  
post #17 of 152 Old 07-09-2014, 11:13 PM
AVS Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 6,255
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 93
Quote:
Originally Posted by zoreo View Post
What has me confused is the fact my set shows these subchannels the full width of the screen when they should be a 16x9 picture within a 4x3 frame like they are on all other SD channels except these two.
Your TV is set wrong for the two PBS 4:3 subchannels. Your TV should be displaying them as 4:3 within the 16:9 image area, with black pillar bars on the left and right. That said, it is very possible that your local PBS affiliate has the aspect ratio flag set wrong. I'd have to do an OTA capture and look that the ATSC data to determine that. In the meantime, try flipping thru the aspect ratio settings on your TV (or whatever the size manipulation is called).

Quote:
Originally Posted by zoreo View Post
OK mrvideo- I have reversed the aspect numbers although having the smaller number first seems more natural to me.
While that may seem natural to you, it is incorrect. For the most part, this is also a technical forum and as such, the terms used should be correct. So please, use the correct aspect ratio terms.

Thank you for your cooperation.

"What do you say Beckett. Wanna have a baby?" - Castle to Det. Beckett
"How Long have I been gone?" Alexis after arriving home and seeing Castle and Beckett w/ the baby - Castle - 11/25/13
Mr. Video
My Geek Images

mrvideo is offline  
post #18 of 152 Old 07-10-2014, 01:04 AM
AVS Special Member
 
Aleron Ives's Avatar
 
Join Date: Oct 2009
Posts: 2,819
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 314 Post(s)
Liked: 367
Quote:
Originally Posted by veedon View Post
Maybe somebody who has greater technical knowledge than I have can explain how a "4:3 SD" picture, which to me should always be 640x480 (in its natural or native resolution) can be turned into a 16:9 image (by a technique other than simply stretching), yet still have different pixel counts or resolutions that are nowhere near the 1920x1080 that I associate with "full HD". Even 720p HD is far more pixels (1280x720) than in the various implementations of "widescreen SD".
Uh, of course 1280x720 has more pixels than widescreen SD. 720p is HD. SD is SD.

Here's a partial explanation of the crazy world of digital SD video:

The reason digital SD is so confusing is that it was kludged together as a way to transfer existing analogue standards (e.g. NTSC and PAL) to digital format. In the NTSC world, the image has a fixed number of lines, ~480 of which are used for the actual image and can be mapped to a digital vertical resolution, but the horizontal resolution is not fixed. This is why a CRT monitor can display any number of resolutions and have them look decent, whereas an LCD monitor can only display material at its native resolution at optimal quality, since the number of pixels on an LCD is fixed.

In order to convert NTSC to digital, the horizontal information is sampled a certain number of times, which was chosen as 720 for several different formats; however, not all 720 pixels are used for image information: some of them are used to carry extra information or as overscan, i.e. a margin of error in case the scanning process doesn't keep the image centered the entire time. As a result, NTSC only actually uses 711 pixels, not 720 pixels, which is why if you look at a raw 720x480 image, there are often black borders on the left and right. Because the overscan isn't particularly important anymore, 720 pixels is often cropped to 704 pixels, because 704 is the nearest value to 720 that is still divisible by 16 (a nice number that makes MPEG compression work more effectively).

So, we have either 720x480 or 704x480, neither of which are 4:3, but that's OK, because digital SD always uses anamorphosis in order to correct the aspect ratio upon playback. Anamorphic widescreen isn't the only type of anamorphosis: 4:3 uses it, too. Regardless of whether your video is 4:3 or 16:9, it's always stored at 720x480, which means the image is distorted. (If it's 4:3, the image is wider, so people are shorter and fatter than normal. If it's 16:9, the image is narrower than it should be, so people are taller and skinnier than normal).

The aspect ratio of the storage medium is sometimes called the Frame Aspect Ratio, or FAR. When you play an SD video, the TV corrects the aspect ratio at the same time it resizes the image to fit your display. If you have a 4:3 image, the 720x480 pixels are upscaled and resized to 960x720 for a 720p display or 1440x1080 for a 1080p display. If you have a 16:9 image, the 720x480 pixels are upscaled to 1280x720 for a 720p display or 1920x1080 for a 1080p display. If you weren't upscaling, the resolutions would be 640x480 for 4:3 and 853.333x480 for 16:9 (but of course there's no such thing as .333 of a pixel, so the horizontal resolution has to be rounded to the nearest whole, even pixel, i.e. 854). The aspect ratio of the final image is often called the Display Aspect Ratio, or DAR. The ratio between the FAR and DAR is sometimes called the Sample Aspect Ratio, or the SAR.

An anamorphic video is stored in the FAR (720x480) and flagged with a SAR. When you multiply the horizontal resolution of the FAR by the SAR, you get the final horizontal resolution used during playback, which when divided by the vertical resolution, gives you the DAR. For example, if you have an anamorphic widescreen DVD and want to process it for your HTPC, the video is stored with a FAR of 720x480, but only 711 of those horizontal pixels are used. You can then crop it to 704x480, but the image is still "squished", so we can save the video with a SAR of 40:33. This simply means that you multiply the horizontal resolution (704) by 40 and then divide it by 33, which gives us a final resolution of 853.333 pixels. If we then divide 853.333 by 480, we get 0.777, which is 16:9. Aha! We have restored the correct DAR!

In HD formats, the FAR and the the DAR match, i.e. the image is stored in the same way it is displayed without being stretched or squished at all. This means that the SAR is 1, and the image has so-called "square pixels". An image with a SAR that is not 1 is said to have "non-square pixels", but it's important to recognise that there is no such thing as a "non-square pixel" when referring to modern LCDs; the term is more of an abstraction used to describe the fact that the shape of the video frame in storage does not match the shape of the video frame when it's being displayed.

Returning to SD video, the main aspect ratio problem occurs when you have 16:9 material presented as 4:3 ("letterboxed widescreen"), so let's consider how that would work.

If you have a 4:3 TV (a CRT, or "tube"), your screen matches the 4:3 image area, so it doesn't matter whether your video is 16:9 letterboxed or 16:9 anamorphic. If it's letterboxed, the 4:3 image just gets mapped to your screen with black bars on it, and you see 16:9 letterboxed. If it's anamorphic, the image wants to be 854x480, but an SD signal can't carry that many pixels, so instead, it gets downscaled to 720x360, the vertical resolution is effectively padded with black bars on the top and bottom to reach the target resolution of 720x480, and then the image is mapped to your screen. The result? You get 16:9 letterboxed, so there's no difference between a letterboxed and an anamorphic widescreen source.

If you have a 16:9 TV, though, then this doesn't work the same way. If you have an anamorphic 16:9 source, the 480 vertical pixels get mapped to either the 720 or 1080 vertical pixels on your TV, and then the horizontal 720 pixels get stretched to either 1280 or 1920 pixels, which fills the horizontal resolution and corrects the image's aspect ratio.

If your source is not anamorphic, though, then you have a problem. The image is 720x480 pixels with only 720x360 pixels containing actual image; 60 pixels on the top and 60 pixels on the bottom of the image are black. The problem is your TV doesn't know that those pixels are useless; it only knows that the image is 720x480 and should be displayed as 4:3. As such, the 480 vertical pixels get mapped to either the 720 or 1080 vertical pixels on your TV, and the horizontal 720 pixels get stretched to either 960 or 1440 pixels, which fills the horizontal resolution and corrects the image's aspect ratio. The result, however, is a "windowboxed" 16:9 image: the black bars on the left and the right of the image are because it's 4:3, so those portions of the screen aren't used at all. The black bars on the top and bottom of the image are not unused portions of your screen, though; they're part of the image. That part of the image just happens to be black and uninteresting to watch, because it's a 16:9 image stored inside a 4:3 frame for convenient viewing on a 4:3 TV.

The only way to correct this is to use the zoom function on your TV, which makes the compression artifacts and the low resolution even more apparent than normal, especially if you have a large TV or sit close to it.

This is why "anamorphic widescreen -- enhanced for 16:9 televisions" DVDs became the standard when widescreen TVs came out, and people would always complain when a DVD was released as letterboxed 16:9, because not only would such a DVD require extra time spent on manual zooming, but that zooming would make image defects even more noticeable.

Unfortunately, many DTV stations show their programs this way, because this may very well be the way the content was originally produced. If they took a 720x480 4:3 image containing 16:9 material, cropped the borders to make it 720x360, resized it to 720x480, and set it as anamorphic widescreen, the image would not look any better (and it might even look worse, since it underwent an extra resizing step and got recompressed); you just wouldn't have to spend extra time using the zoom button on your remote control anymore.

Are you still reading? Isn't digital video fun? If you really want the nitty-gritty on digital video, try reading this article and see if your head explodes.
tubetwister likes this.

Last edited by Aleron Ives; 07-10-2014 at 01:13 AM.
Aleron Ives is offline  
post #19 of 152 Old 07-10-2014, 04:19 AM
AVS Special Member
 
wuther's Avatar
 
Join Date: Aug 2008
Posts: 1,437
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 33
Quote:
Originally Posted by mrvideo View Post
For us to see what you are seeing, take a digital photo of the screen and post it.
This would help indeed.
wuther is offline  
post #20 of 152 Old 07-10-2014, 09:01 AM
AVS Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 6,255
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 93
Quote:
Originally Posted by Aleron Ives View Post
Here's a partial explanation of the crazy world of digital SD video:
Very good explanation.

What kinda sucks is that ATSC allows for a couple of SD image sizes. While 720x480 is the ideal for old NTSC material converted to digital, the ATSC spec actually calls for 704x480 (4:3 or anamorphic 16:9) or 640x480 (4:3 only). The problem is that the FCC does not require stations to only use those two SD formats. 720x480 is allowed because it is within the limits of Main Profile @ High Level. Stations have been known to use 352x480 in order to save bandwidth. The image will probably look like crap, but who cares, as long as it brings in the $$$. Many stations don't care about HD quality, so why care about SD quality.

BTW, as a side note, in the digital world NTSC, or PAL, does not exist. NTSC and PAL are OTA analog transmission standards. NTSC has been used to describe analog tape based devices as well, even though most recorded the color in a different format. Plus, the video and audio are separate on tape and playback. That said, what was recorded on analog tape was damn close to what was transmitted.

In the digital world, all of that is gone. No more vertical, or horizontal, sync pulses. No more color burst, hell no more separate luminance and color for that matter. SD video should not be labeled as NTSC or PAL. Hell, I've even seen 1080i29.97 labeled as NTSC. If it is 29.97/59.94, it is NTSC. If it is 25/50 it is PAL. Wrong, all wrong. For some idiotic reason, I've even seen 23.976 digital video labeled as NTSC.

Sorry, I'll climb off my soapbox now.

"What do you say Beckett. Wanna have a baby?" - Castle to Det. Beckett
"How Long have I been gone?" Alexis after arriving home and seeing Castle and Beckett w/ the baby - Castle - 11/25/13
Mr. Video
My Geek Images

mrvideo is offline  
post #21 of 152 Old 07-10-2014, 10:52 AM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Quote:
Originally Posted by wuther View Post
This would help indeed.
OK for those who want a picture here's one. I took this without flash to avoid glare so I brighten up the blacks in this picture so you can see the frame of the TV and the edge of the screen.

Notice that the info box says "480 I" but the picture goes the full the width of the screen even though set aspect is set to "normal" and on other 480 I channels shows the picture stopping at the little yellow arrows at bottom that mark the correct boundary of a normal 480 I picture.

zoreo is offline  
post #22 of 152 Old 07-10-2014, 11:26 AM
AVS Special Member
 
Brian Conrad's Avatar
 
Join Date: Jan 2001
Location: Martinez, CA, USA
Posts: 4,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 169 Post(s)
Liked: 147
I was at Fry's yesterday and they had the new LG 21:9 computer monitors on display and sale. That'll take care of those "black bars" for ya.
CinemaAndy likes this.
Brian Conrad is offline  
post #23 of 152 Old 07-10-2014, 11:51 AM
AVS Special Member
 
jjeff's Avatar
 
Join Date: Nov 2007
Location: Minneapolis MN
Posts: 9,865
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 140 Post(s)
Liked: 90
Quote:
Originally Posted by Brian Conrad View Post
I was at Fry's yesterday and they had the new LG 21:9 computer monitors on display and sale. That'll take care of those "black bars" for ya.
I've also been looking at one at Costco but the problem is with a 29"(I think that was the size) diagonal screen the picture height is only like a 20" 16:9 or 16" 4:3
(I could be all wrong on my numbers but the point is with a 21:9 screen one would need a really large diagonal size to get the vertical height one is used to). With tube technology one could never do such wide aspects(which is why I believe our current ATSC standard is 16:9 and not wider) but with flat panels the sky is the limit.
tubetwister likes this.
jjeff is offline  
post #24 of 152 Old 07-10-2014, 12:57 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Well I'm not a believer that wider is always better. The wider a screen is, the relatively smaller it is vertically, and vertical size is very important. I think the 16:9 ATSC standard is a good compromise. There is rarely anything important at the edges of screens wider than that. Early movies and TV did OK for decades using a 4:3 screen.
zoreo is offline  
post #25 of 152 Old 07-10-2014, 02:06 PM
AVS Special Member
 
Brian Conrad's Avatar
 
Join Date: Jan 2001
Location: Martinez, CA, USA
Posts: 4,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 169 Post(s)
Liked: 147
Quote:
Originally Posted by jjeff View Post
I've also been looking at one at Costco but the problem is with a 29"(I think that was the size) diagonal screen the picture height is only like a 20" 16:9 or 16" 4:3
(I could be all wrong on my numbers but the point is with a 21:9 screen one would need a really large diagonal size to get the vertical height one is used to). With tube technology one could never do such wide aspects(which is why I believe our current ATSC standard is 16:9 and not wider) but with flat panels the sky is the limit.
The LG display was pushing using them so you could have multiple documents up horizontally but I would still want one as least as tall as this 19" 16:9 monitor. I think larger displays will be coming. Right now the price (around $400) is a little steep.

Zoreo, the Lumiere brothers camera filmed in 1:66:1 or 5:3. This probably because they were selling film for 3x5 postcards. 4:3 is a bit constrained for story telling and really only good for talking heads.
Brian Conrad is offline  
post #26 of 152 Old 07-10-2014, 02:20 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Quote:
Originally Posted by Brian Conrad View Post
Zoreo, the Lumiere brothers camera filmed in 1:66:1 or 5:3. This probably because they were selling film for 3x5 postcards. 4:3 is a bit constrained for story telling and really only good for talking heads.
Well there were many great movies like "Gone with the Wind" and the "Wizard of Oz" made in a 4:3 format (1.37:1) and for 50 years movies were shown on TV chopped to 4:3 and people watched without problem.

But I'm not advocating we go back to 4:3- just not some of these ridiculously wide formats like 2.5:1 that some people are advocating.
zoreo is offline  
post #27 of 152 Old 07-10-2014, 03:23 PM
AVS Special Member
 
Brian Conrad's Avatar
 
Join Date: Jan 2001
Location: Martinez, CA, USA
Posts: 4,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 169 Post(s)
Liked: 147
I have a few classic 4:3 movies. One, "Citizen Kane" I was watching once on DVD and noticed that in about every frame there was empty space at the top and sometimes at the bottom depending on the scene. If you read up on or watch some of the documentaries about famous cinematographers, many were painters and some were still photographers too. I think that some of them were mentally framing within the 4:3 aspect for a wider frame. This is an artistic medium and plays were produced for years on broad stages with about a 2:1 aspect ratio.

Early cathode ray tubes were round so many early TVs had round sides. Eventually square tubes became available for TV. My folks bought a 21" Magnavox around 1954 with a square tube. When widescreen TVs became available in the early 1990s mainly for laser disc enthusiasts I recall reading articles from engineers about how difficult it was to make a CRT that worked for 16:9. Of course these days it is a moot subject with flat panels.

Sydney Pollack on his preference for widescreen:

Most good sets and inexpensive ones have zoom settings where you can eliminate any "black bars" you don't like or even get rid of the default overscan which will cut off edges of "scope" movies though not entirely the top and bottom masks. A few years back when I was visiting friends at their vacation home they were watching a football game on a 4:3 TV. I asked, "where is the rest of the game?" The husband cracked up because he had seen my widescreen TV and knew what I was referring to.
Brian Conrad is offline  
post #28 of 152 Old 07-10-2014, 03:56 PM
AVS Special Member
 
wuther's Avatar
 
Join Date: Aug 2008
Posts: 1,437
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 33
Quote:
Originally Posted by zoreo View Post
OK for those who want a picture here's one. I took this without flash to avoid glare so I brighten up the blacks in this picture so you can see the frame of the TV and the edge of the screen.

Notice that the info box says "480 I" but the picture goes the full the width of the screen even though set aspect is set to "normal" and on other 480 I channels shows the picture stopping at the little yellow arrows at bottom that mark the correct boundary of a normal 480 I picture.
I am confused now. Your first post wrote about HD yet this appears to a SD (World?) channel.

Last edited by wuther; 07-10-2014 at 03:59 PM.
wuther is offline  
post #29 of 152 Old 07-10-2014, 04:25 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
There are trade-offs to everything. And as I said above I'm not saying we should go back to 4:3- I agree that's too limiting. But too much in a picture is bad too- it distracts from what's important and makes the important thing smaller and harder to see. Yes, you can use zoom to make it bigger- but then you lose definition so it's not as clear.

So you can choose to show a lot of miscellaneous stuff on the sides with a very wide picture or focus on what's really important- making it big and easy to see with a more narrow format.
I think for the size of picture most people watch at home 16x9 strikes a pretty good balance between these objectives.
zoreo is offline  
post #30 of 152 Old 07-10-2014, 04:28 PM - Thread Starter
Member
 
zoreo's Avatar
 
Join Date: Feb 2004
Location: Lehigh Acres, FL
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 10
Quote:
Originally Posted by wuther View Post
I am confused now. Your first post wrote about HD yet this appears to a SD (World?) channel.
Well I was confused too- why was what was suppose to be a 4:3 SD picture filling the width of a 16x9 HD screen?
zoreo is offline  
Reply HDTV Programming

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off