1080p and the Acuity of Human Vision

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admin

Audioholics Robot
Staff member
"1080p provides the sharpest, most lifelike picture possible." "1080p combines high resolution with a high frame rate, so you see more detail from second to second." This marketing copy is largely accurate. 1080p can be significantly better that 1080i, 720p, 480p or 480i. But, (there’s always a "but") there are qualifications. The most obvious qualification: Is this performance improvement manifest under real world viewing conditions?


Discuss "1080p and the Acuity of Human Vision" here. Read the article.
 
Adam

Adam

Audioholic Jedi
Great article. Thanks for posting it. It's nice to get grounded in reality from time to time.

I think that it would be very useful to have an equation that relates viewing distance, screen size, and max-required resolution (probably already exists, but I haven't looked for it). Another idea would be a table that would contain viewing distance and discrete resolutions (e.g. 480, 720, 1080) as row and column titles, and then the table would contain the smallest screen sizes for which the user would want that resolution at each viewing distance.
 

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BMXTRIX

BMXTRIX

Audioholic Warlord
Great article. Thanks for posting it. It's nice to get grounded in reality from time to time.

I think that it would be very useful to have an equation that relates viewing distance, screen size, and max-required resolution (probably already exists, but I haven't looked for it). Another idea would be a table that would contain viewing distance and discrete resolutions (e.g. 480, 720, 1080) as row and column titles, and then the table would contain the smallest screen sizes for which the user would want that resolution at each viewing distance.
Good reading...
http://forums.audioholics.com/forums/showthread.php?t=30364

The S&V Article was one of my favorites and the charts are a great reference for many. I'll be back to comment on the AH version...
 
BMXTRIX

BMXTRIX

Audioholic Warlord
That's some good information, but definitely lacks the meat of how this applies to 1080p vs. 720p (768p?) in the video world. I would also have simply avoided the explanation of arcminutes and simply said "1/12th of one degree is 20/20 visual acquity and about 1/30th of 1 degree is the limitation of discerning objects" Then tied it altogether with what the heck it actually matters to any of us.

The S&V chart is a great example of mapping out why 1080p matters - and more importantly, when it does not. Most people tend to say that 1080p matters only above 50". That simply isn't the case, resolution is all about the screen size, versus your viewing distance, versus your actual ability to see. A person with 20/20 vision sitting about 1.5x the screen WIDTH (not diagonal) is going to visibly see the pixel structure of whatever display they are viewing if it is 720p. But, this puts someone about 6 feet from a 50" display... which most people would find annyingly close for day to day viewing anyway!

It has always seemed to me that 1080p was overblown for most viewers. It's great marketing, but reality maintains that most people think that a 42" plasma, viewed at 10 feet, is HUGE!

It isn't, in fact, it tends to be a bit small. Yet, many people don't feel that way. But, they do think that 1080p matters. How silly. :)

The other determining factor, which is incredibly critical to all of this, but is rarely discussed... The source material.

It isn't enough to have a 1080p display. You have to feed it 1080p! Since most people include things like DVD (480i) and SDTV (480i) and HDTV (720p/1080i) in their typical viewing habits, it is only a few select sources that can even deliver true 1080p content. What matters though is that a person who watches a lot of regular TV needs to make their screen size smaller for that content. Resolution doesn't even matter that much!

Instead, the important factors remain contrast and color accuracy, because those are far more noticable than resoluiton. I would add that a display with a good processor inside will also show a much better looking image than those with cheap processors. Vizio, is one that I would consider to have 'weak' processing, while Panasonic tends to be better. You may have lower resolution (or the same) with Panasonic, but the better processing combined with similar contrast will deliver a better image from the Panasonic to most viewers. Only when the source jumps up in quality, and you are actually sitting close enough, does higher resolution matter.

ie: I have a 854x480 42" plasma in my master bedroom. This is the bedroom where our heads sit about 13 feet from the screen. Upping the resolution to HD levels (1024x768) or to 1080p? Wouldn't make a damn bit of difference to my viewing quality.
 
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westcott

Audioholic General
I doubt many people could tell you what the were watching at 16 feet, whether it be 1080i,1080p. or 720p on a 100" screen.

I can't.
 
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BradB

Enthusiast
Obvious difference

I saw a sales demo between 1080p and 720p side by side, and I question whether people who don't see the difference should be allowed behind the wheel of a car.

I admit that you could easily degrade a 720p signal to rig this. But this is not the first time I've seen 720p displays, and I have never before seen image clarity anywhere near what I saw on the 1080s.

I appreciate the measurement on human vision, but that oversimplifies things. We are not looking at 1 pixel, or 1280 completely unrelated pixels, we are looking at an image.

To me, 480p looks like TV I grew up with. It is obviously a picture with obvious blurring and other obvious problems, but you can tell what it is. 720p looks amazing by comparison, and allows things to get artistic, but it is still a picture. 1080p starts to blur the line between seeing reality and seeing pixels. I think we are going to need a even a higher resolution than 1080p to completely eliminate pixelation.

Before anyone posts anything about the limits of human vision or the lies of evil salesman, take a look at a 1080p display with a blue ray player yourself.
 
BMXTRIX

BMXTRIX

Audioholic Warlord
I saw a sales demo between 1080p and 720p side by side, and I question whether people who don't see the difference should be allowed behind the wheel of a car.

I admit that you could easily degrade a 720p signal to rig this. But this is not the first time I've seen 720p displays, and I have never before seen image clarity anywhere near what I saw on the 1080s.

I appreciate the measurement on human vision, but that oversimplifies things. We are not looking at 1 pixel, or 1280 completely unrelated pixels, we are looking at an image.

To me, 480p looks like TV I grew up with. It is obviously a picture with obvious blurring and other obvious problems, but you can tell what it is. 720p looks amazing by comparison, and allows things to get artistic, but it is still a picture. 1080p starts to blur the line between seeing reality and seeing pixels. I think we are going to need a even a higher resolution than 1080p to completely eliminate pixelation.

Before anyone posts anything about the limits of human vision or the lies of evil salesman, take a look at a 1080p display with a blue ray player yourself.
Brad, this is a great post, but misses some of the details that are important to what you are saying.

1. Was the source material 1080p/720p/480p/480i or was the display 1080p/1080i/720p/480p/480i? Or both?

It matters a great deal that people understand that 1080p isn't just about the display, it is about the display combined with a great source. I would daresay that you (Brad) likely couldn't tell the difference between Blu-ray or HD DVD played on a 1080p 50" plasma or a 720p 50" plasma at about 13 or 14 feet. Unless, of course, the scaling of the 720p plasma is not good.

There are huge jumps in video quality and the most accurate form of video is uncompressed feeds. Pixelization is NOT something the average human sees. What we tend to call pixelization is far more often compression artifacts. That is, you aren't seeing the individual pixels, but rather a byproduct of the compression that was used for the specific type of video feed you are watching. Analog cable is one of the worst with image quality, but this is generally noise on the line. Digital cable/satellite is better, but still is highly compressed MPEG2. HDTV is compressed much less, but still must go through many connection points for live TV along with real time compression. DVD is not real time compressed and despite not having the bit rate of HDTV, it still is a carefully monitored process of a known source that can be truly tweaked for excellence in quality.

Blu-ray and HD DVD are in another class. Their data transfer rates are far above broadcast HDTV and the advanced codecs allow for far superior quality at those allowed data rates.

Unfortunately, the test between 480i, 480p, 720p, 1080i, and 1080p is rarely valid. What you want to see is a quality HD source, like Blu-ray/HD DVD and then split it between a 1080p, 1080i, 720p, 480p, and 480i display, then see where you actually notice a difference.

FYI: I had a customer of mine go buy their plasma. The sales person showed them a 720p model and a 480p model. The price difference, at the time, was about 500 bucks. I told them to stand at the distance they would be sitting in their home. While they politely nodded at the sales guy, they told me privately (as I thought they would), that they could see ZERO difference in the displays from their seating distance. Up close? Yes! But not from their seating distance.

Point of the story? Buy Blu-ray or HD DVD and spend a little less on your display! ;) :D
 
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BradB

Enthusiast
One source was clearly 1080p out of a blue ray player. The other source was just labeled "DVD". I am guess it was 720p - it was clearly much better than 480i.

I completely agree this is in the context of the source material, and for most of what is available now, it doesn't matter.

I am familiar with compression artifacts, and can say I am talking about pixelation. To be fair, it is much more obvious with some pictures than others. Landscapes, for example, look the same, unless you see a picture that shows each leaf on a tree. But I have never seen a human face on 720p in hard lighting that I could say looks completely "real". The 1080p displays simply went far beyond anything I've seen or thought possible.

My main point is I don't think the difference is subtle or questionable at all, and I am surprised so many people talk as if it is. If you've all actually seen good 1080p from blue ray on a new LCD and say it looks the same or worse than 720p on a good plasma, then I either have super human vision, or more likely I've never seen a good plasma. But I think a lot of people are basing reviews on sources that don't show off the full capability of 1080p, or are just speculating about how human vision works, and a lot of people are reading those reviews and posting their own without actually seeing a 1080p.
 
M

mjhamre

Audioholic Intern
...My main point is I don't think the difference is subtle or questionable at all, and I am surprised so many people talk as if it is. If you've all actually seen good 1080p from blue ray on a new LCD and say it looks the same or worse than 720p on a good plasma, then I either have super human vision, or more likely I've never seen a good plasma. But I think a lot of people are basing reviews on sources that don't show off the full capability of 1080p, or are just speculating about how human vision works, and a lot of people are reading those reviews and posting their own without actually seeing a 1080p.
I have seen both side by side, and while I agree that if I am close enough there is a significant difference, I also completely agree with the basic point of the article (and the comments two posts back) which is that from the distance that a lot of people wind up doing their viewing, for the size screen that a lot of people wind up viewing, the two look the same (with appropriate sources).

Having said that, when I upgrade my 42" old school 480 line plasma, I am going to wait until there is a 1080 one in my price range, even though at my 10 foot viewing distance I'm not sure I could pass the Pepsi challenge.
 
M

MDS

Audioholic Spartan
The point of the article and the sound and vision chart in the same vein is for a display with a native resolution of 1080p (1920 x 1080 pixels) displaying a standard HD resolution such as 720p or 1080i and NOT for the same display showing an image from a true 1080p source.

If the source does not match the native resolution of the display, it has to be scaled. If you sit far enough away the eye generally cannot discern all of the detail available and thus a native resolution of 720p will look the same as a native resolution of 1080p.

I've said it before but it bears repeating: a 640 x 480 resolution on your computer monitor (VGA) looks horrid when you sit two feet away. If you can back off to 10 feet or so it doesn't look so bad and that is the point.

Ironically, the point is probably moot anyway as all displays in the near future will be 1080p native resolution. That is the trend and marketing will convince the average buyer that 'more is always better' and everyone will clamor for the latest 1080p displays.
 

Micker

Audiophyte
resolution

I also agree that the resolution has more to it then just seeing the pixels or not. There is more information in a 1080p picture then a 720p picture. It not only enhances detail, but also colors, and edge transitions. The picture takes on a fuller more complete look. Also, many people have VERY good eyesight, like myself, and on big screens, like my 62" dlp at 10', 1080p is noticable. I'm sure if you took a 720p signal on one screen and a TRUE 1080p signal on another, with a source that was pristine, you would see a difference in all aspects of the picture with higher resolution.

The biggest problem with high def, like a poster stated above, is compression. Resolution doesn't matter when you have a pixelated mess of a signal. I doubt that most cable/sat feeds are good enough to showcase the diferences in resolution. Even a lot of hd/blu ray stuff are crap transfers. We need to focus on BETTER SOURCE MATERIAL, before we worry about 1080p vs 720p. Once we start getting HIGH bit rate, perfect transfer sources, then hdtvs that accept 1080p/24 will really start to pull away.
 
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wseaton

Audiophyte
Amen.

My father has a 65" Pioneer Elite, which was one of the last/best CRT based rear projection sets you can buy. I have a 31' Toshiba regular CRT based set in my bedroom, and a 42" HiDef Samsung LCD in the living room.

I consider myself extremely fussy when it comes to video playback given I did video analysis of film based source for years and was one of the first adopters of both laser disc and DVD.

I hate to say it, but the truth is that CRT based Pioneer Elite and my 31' Toshiba provide far superior displays for 100% of conventional broadcast and DVD. The Elite beats my Toshiba obviously because of progressive scan, but my Samsung doesn't always beat the 31" Toshiba when it comes to DVD. The CRT based Elite provides a superior picture over more modern scaled displays like LCDs for about 80% of HiDef material.

Why? Because the CRTs based displays are far more tolerant of compression artifacts and sloppy mastering while more high tech displays show every bad pixel, dithering, artifact, etc., then scale it to make it even worse. When I'm watching 720p on the Elite I'm not reminded that I'm watching a digital signal pumped and enhanced through many IC chips and digital scaling algorithms. Every 1080p LCD I've watched does.

This is obviously a problem with source materials though, the majority of which are still in the dark ages. Another problem is without an extensive library of 1080p source material manufacturers are free to claim 1080p as they want without a real market to do subjective comparisons. Case in point were first generation DVD players and movies which were painfully full of artifacts and comb filtering problems because of poor compression standards.
 

Micker

Audiophyte
hd

I agree that the biggest concern today shouldn't be if 1080p is better then 720p etc., but compression of the feeds we get. The weak link right now is compression, esp. for cable/sat signals. We aren't seeing the best we can on most video sources. Our tvs are capable of producing even sharper, more vibrant pictures, but we are at the mercy of the compression gods.

Hopefully, they will start to take advantage of BD50 disks and start mastering material with very high bit rates and take time with the transfer. Otherwise, we might be getting 1080 resolution, but with artifacts/banding/noise, what good is it??
 
E

European

Audiophyte
Yes, I agree...

Take a look at:

BBC Research & Development White Paper: WHP092
Tests of visual acuity to determine the resolution required of a television transmission system
John Drewery, Richard Salmon
http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP092.pdf

It has a handy chart showing size of screen vs required resolution for average visual acuity and average TV viewing distance, and concludes that 720p is, on average, just adequate for a 50" screen.

What all of this discussion ignores is that Red, Green and Blue sub-pixels are not coincident on LCDs/Plasmas, hence you will get improved picture rendition from a higher resolution panel than one might think would be required. The BBC paper only considers the TV transmission standard, not the display type.

"European"
 
E

EnzoPolotso

Audioholic Intern
One source was clearly 1080p out of a blue ray player. The other source was just labeled "DVD". I am guess it was 720p - it was clearly much better than 480i.

I completely agree this is in the context of the source material, and for most of what is available now, it doesn't matter.

I am familiar with compression artifacts, and can say I am talking about pixelation. To be fair, it is much more obvious with some pictures than others. Landscapes, for example, look the same, unless you see a picture that shows each leaf on a tree. But I have never seen a human face on 720p in hard lighting that I could say looks completely "real". The 1080p displays simply went far beyond anything I've seen or thought possible.

My main point is I don't think the difference is subtle or questionable at all, and I am surprised so many people talk as if it is. If you've all actually seen good 1080p from blue ray on a new LCD and say it looks the same or worse than 720p on a good plasma, then I either have super human vision, or more likely I've never seen a good plasma. But I think a lot of people are basing reviews on sources that don't show off the full capability of 1080p, or are just speculating about how human vision works, and a lot of people are reading those reviews and posting their own without actually seeing a 1080p.
They should have used Blu-Ray at 1080p, and Blu-Ray at 720p for a fair comparison. Obviously a DVD upscaled to 720p is not going to compete with a 1080p Blu-Ray disc.
That comparison is completely bunk.
 
emorphien

emorphien

Audioholic General
Viewing distance and the required resolution are very important. Money is wasted on 1080P if you're sitting far enough away that you can't resolve the difference between 720 and 1080. All the same, if you've got the money to burn or know you might be rearranging then that obviously may change.

I know there are certainly some home theaters I've seen where 720P was fine, the seating distance was far enough that it works just fine. In fact for my preferred seating distance (in relationship to TV size) I would probably be fine with something in the 800-900 range resolution wise, even though my corrected vision is better than 20/20.

This is nothing new to me though, human vision was forced down my throat right at the start of my graduate program.
 
R

renindy

Audiophyte
Glad the topic was brought up

Glad the topic was brought up.

Clearly (no pun intended!),
Different pairs of eyes will discern images differently won't they?

Look what Yves Faroudja did for plain ol' NTSC video, (with his "line doubler") long before HDTV was even talked about. This technology offered a signfican't upgrade using ordinary NTSC, at a time when "projection" tv sets were nearly an immediate turn off with the obvious blurring, registration problems, dot crawl & other NTSC artifacting present.

Whether we can agree on the merits of i vs p, its certainly a trend in a good direction. We can always scale back in terms of application, but to have it there in hand is always a good thing. I doubt if most of us would want to change our computer monitors' modes FROM progressive TO interlaced.
: )

Lets take this display development towards progessive & use it to our advantage, especially if the marketing people don't kill it with un realistic price points etc.

Don
 
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MrPirate2882

Junior Audioholic
I think there is a clear difference between 1080p and 720p on large displays, 60"+. I doubt you'd be able to tell the difference if the resolution were greater than 1080p.

It is 100% dependant on the screen size. Since I got a 50" DLP (only does 720p), I find myself disappointed when I watch movies in a theater. Since theaters have gigantic screens and despite the fact that the resolution in the theater is higher than 720p, the massive size of the displayed image makes it blurry compared to a decently sized HDTV.

If you've got a massive television, 1080p should make a big difference, if you don't you won't be able to tell.
 
BMXTRIX

BMXTRIX

Audioholic Warlord
It is 100% dependant on the screen size
Actually, the point of most of these posts is that your statement is 100% incorrect.

Maximum resolution is based on human visual acquity and it is a ratio of screen size to viewing distance based upon a highest quality source available.

If you stand 10" from a 50" 1080p display it will look far worse than if you stand 10 feet from a 19" 480i display. There is a scientific way to test these results and measure human vision, but it comes down further to basic common sense.

Saying that it is just screen size, does not make sense and is not correct, but will confuse people who may read this and think it is accurate.
 

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