The actual quality of HD

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LostPacket

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Master Geek

#140645 26-Jun-2008 08:57

DaveB:
pollock:

But now people are saying that 1080i is actually better then 720p for sports here is a interesting article from AVS
http://www.satelliteguys.us/old-voom-chit-chat-archives/20592-interesting-discussion-1080i-vs-720p-battle.html

Im not taking a Dig at you at all just want to understand more where you coming from.

If you take a look at that thread you will see it is 4 years old so I would not read too much into it. A LOT has changed in that time.

Here is a much more up to date (and I would suggest respectable) article where 720p is declared the preferable format, especially when any compression is used.

Industry declares 720p better than 1080i

http://whathifi.com/blogs/television/archive/2008/03/11/news-industry-declares-720p-better-than-1080i.aspx

Personally, although I can plainly see the difference between SD and Hi-Def on my laptop, my pc and my 50 Panasonic Plasma, I just cannot see any difference between 1080i and 720p. My wife on the other hand believes that she can!

Cheers DB

Im still trying to figure out why sky is going with 1080i and that the only article that I have found that makes some sense of the whole Saga,

On Paper 720p should be a lot better, I can't tell the difference between 720p/1080i

Most people can't tell the difference between 1080p and 720p. Often a well calibrated 50" screen running at 720p will look 10 times better then a screen that's not calibrated running at 1080p

sbiddle

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#140647 26-Jun-2008 09:14

I think the real issue is not whether you can tell the difference between 720p and 1080i but why we actually need a 1080i format.

All panels are progressive scan. This means that the TV requires a deinterlacer to convert the signal from interlaced to progressive before it can be displayed. Interlaced pictures were required for CRT TV's - these are now obsolete and interlaced video signals should be as well!

An expensive hardware deinterlacer (as used by TVNZ and broadcaster who have adopted 720p) is argueably far superior to the cheap $5 circuit in your expensive TV. The issue is really the fact that the signal has to be converted somewhere in the chain before you can view the picture on your screen - why not let the broadcaster do this with a decent hardware deinterlacer before it's transmitted?

The other issue to factor in is that many STB's can also do conversion themselves which makes a picture worse. Typically a STB will output in a fixed format - ie 720p or 1080i which means that if you're selecting 1080i as an output format it is having to convert the 720p signal to 1080i for it to then be deinterlaced again by the TV. Many STB's cannot output individual channels in their native format.

We are reastically never going to see 1080p broadcasts due to the bandwidth requirements, it's just a shame that many people seemed to equate 1080i as being step up from 720p when it's not.

Masterpiece

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Master Geek
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#140926 27-Jun-2008 15:55

Hi, I was pointed to this thread via my intial welcome msg to Geekzone.
I am afiliated with ISF, as an acredited calibrator.

I think you guys miss some crucial points when debating what you perceive or don't perceive in many cases.
Putting the effects Interlaced, Progressive aside for the moment.

Resolutions and scalings.
Foremost whenever you change the scalings or resolution anywhere in the video chain you create loss and/or artifacts.

Listing the resolutions
PAL, 720*576
HD(It is considered HD when any resolution is greater than 720*576)
1280*720
1920*1080

You need to think of these sizings in another form,
576=414720 pixels or points of data infomation.
720=921600
1080=2073600

One can see clearly the jump from standard PAL to HD720 then HD1080.
What this means is the steps of graduation is finer and finer the higher the resolution, say for example a grey ramp or shading.

Ill add another size, a common screen size.
1366*768=1049088

Notice how it is neither 720 or 1080, the only relavent bit is the ratio, 16:9
So viewing material on the above screen size will create loss and/or artifacts going down or up to the native screen size to display the image.

This is one reason the viewer cannot perceive a major difference between the material.

The next major reason is because of our visual limit, discribed by the Nyquist visual limit.
In a nut shell our percieved range of detail where everything in a space blends together, like the Red, green and blue dots laying side by side on your plasma screen appearing to you as white, grey, black or the combination of colour range those 3 primaries can produce.

Now if you understood that, when viewing a 1080 or 720 image the range you the viewer sits is important to actually discern a visual difference. (let alone if it scaled at any point)
For example it is pointless to buy a 1366*768 32in screen if you are to sit 4metres from it and expect to see a difference, you wont, you cant, except the bionic man of course.

In an ideal world, if one could afford it, the screen size for you would be based on the distance from your seating position to the screen and fill 30deg of your field view, as opposed to 11deg for standard def.

Now a critical bit, perception of the non real reality.
You are fooling your brain you see depth, 3D when viewing material. The more accurate to source, the finer the resolution the greater the effect of deception.
Calibration of the display aids this effect along with resolution and finer detail as the shades are more readily diserned.

Where differences in scalings and resolutions is seen better is with a 1080 projector and you are setup at the correct field of view range.

You will see adifferences in stock 576 signal vs any of the HD resolutions. If you can't it is because something is altering the signal resolution or some other factor along the video chain.
Most TV's upscale the standard def image so the actual effect is lessoned to some degree. However if you viewed side by side the exact same material, one at 576 native on a HD display then the other with HD source you will see artifacts, like colour blending, poor shading, banding and so forth.

regards
nigel

Me:"I'm not a robot!"

ET: "Maybe; you have some freewill, but you chose your path by arrangement"

Me "That sounds like a program with no freewill?"

ET: "We will catch up when you end this cycle"

Me: "Sounds like a 'KPI'!"

ET: "Did you read the terms and conditions?"

Me: .....

Disrespective

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#140942 27-Jun-2008 17:00

Very nice post Masterpiece, informative too. Stick around, it's always good to have some more video smarts around to glean off of.

argo

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#140984 27-Jun-2008 20:37

Hi Masterpiece - I second Disrespective's sentiment!! :-)

Seeing how you know something about this can I pose a real-world scenario? Good, thought you would say yes!

I'm in the process of investigating the most suitable (quality, cost, future-proof) replacement display for the family's lounge CRT.

Heres the situation:

a) Rectangular lounge of 4m x 5m
b) Anticipate wall-mounting panel, on one of the "long" walls
c) Viewing distance would be between 3000-3500mm
d) Viewing angle would be from 0-degrees and 45-degrees (absolute worst angle) from panel-perpendicular
e) Anticipated Video Inputs: FreeviewHD (so: 720p/1080i), DVD (so: 576i?), BluRay eventually (so: 1080p native)
f) Viewing patterns: Daytime: Kid's educational programming (not!) & Wife's social conscience/educational programming (not!!)
Nighttime: Some more of the above, but most importantly also: Movies, Sport, educational sci-fi (or in other words I grab the remote!!).

- Current purchase thinking: Pioneer 50" 8th generation plasma (yeh saving our dollars for this!)

- Reason: Every review I have read puts the Pioneer Plasmas at the top of pile for IQ (unfortunately also reflected in the price). Downside of plasma's lower level whites is not really a problem for me as who really cares if Ellen or Oprah's backdrop is not sunshine white! Now the nighttime viewing is where I figure the rich contrasts, deep blacks, high depth perception & shudder free sports is going to make a plasma the best panel for us. Why a Pioneer panel? Pioneer gets excellent reviews and the one thing almost raved about is the Pioneer panel's image processing capability.

- Dilemma1: We're talking about spending a fair bit of coin here! Therefore have I got all of the above about right? Certainly my visits to AV stores, that actually make an effort to setup their stock to something other than store-mode, seems to bear all this out.

- Dilemma2: Should I save (and save) to get the PDPLX508G (1080p model) Pioneer, or will the PDP508XG (720p/1080i) model be as close as dammit to the LX given all above?

Any thoughts on my "dilemmas" would be very gratefully received!

stuzzo

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#141004 27-Jun-2008 21:55

sbiddle: I think the real issue is not whether you can tell the difference between 720p and 1080i but why we actually need a 1080i format.

All panels are progressive scan. This means that the TV requires a deinterlacer to convert the signal from interlaced to progressive before it can be displayed. Interlaced pictures were required for CRT TV's - these are now obsolete and interlaced video signals should be as well!

As mentioned by someone previously there is quite a split in the broadcasting industry in use of the 1080i format versus 720p. While I don't know all the reasons for this I would imagine Sky and their affliates would have done more than toss a coin to decide which way they would go. I guess one would have to know more about the whole broadcast chain both technically and financially to have more insight in that.

I wonder if they decided that the movie content and other material (most TV series I believe) they might be getting at 1080p24 was going to be most important and that the sports broadcasts wouldn't suffer greatly as a result. One would also assume that within a few years most new lounge size TVs will be sold at 1080p.

If so then they wouldn't broadcast at 1080p25 as a large proportion of current HD TVs couldn't accept it and so 1080i50 with the TVs having the opportunity to do the inverse telecine would be the only option.

So I would suggest 1080i is the only practical way to get 1080p to the home.

You'd have to think that 1080i has a little bit of a marketing edge over 720p as well to be cynical.

We are reastically never going to see 1080p broadcasts due to the bandwidth requirements, it's just a shame that many people seemed to equate 1080i as being step up from 720p when it's not.

Most broadcasting authorities are looking to 1080p50 or 1080p60 as the future broadcast standard which is feasible with the use of the mpeg-4 codec.

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Masterpiece

247 posts

Master Geek
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#141738 30-Jun-2008 23:33

Argo, remember unless you upgrade regulary your choice is with you for a while. In CRT days not so long ago the only real concern was size. Now the current displays have so many options and considerations to take into account it gets confusing and very difficult to future proof since a number of options may change by the time they come about...HDMI 1.1 2 3 for example.

Im a projector man and I plan on getting a 1080p PJ to replace my aging(but still good) AE900E (720p)one day.
I still use a old CRT for news and stuff, but do plan on getting a basic panel for general TV duties at some stage, a new bathroom comes before that though.....and some insulation....and ....

The pioneers do have the edge, although the next generations will have Pany panels I believe with their systems.

Don't get concerned about white levels, they all have ample output these days and generally when calibrated get dialed back to levels that don't harm your vision. Yes you can harm your eyes watching these displays with dark viewing and medium/high contrast(defaults)

Most displays trick you into thinking they are brighter than they are anyway with generous use of over saturated green primaries(our dominant spectra) and pushed blue contrast.

When looking at these panels, ask for the remote and make sure all the special features are turned off like black enhancements and so on.

Sizing is tricky, as I stated Im a PJ man, maybe they will die off like technology does, but for panels I see 1080's being standard afare one day, for now dispite freeview being 720p/1080i this is only a bandwidth restraint it could possibly change. Blueray though will become the dominant force eventually over std def DVD for home viewing, personally I would look at this as the current setup positioning than the freeview options.
Consider your video chain also, the weakest link will possibly be the dominant factor in quality. ie don't spend a fortune on a display if you never plan on using the full capability with DVD options.

Quite often a well tuned/calibrated modest system will be better than a mismatched topend system.

Me:"I'm not a robot!"

ET: "Maybe; you have some freewill, but you chose your path by arrangement"

Me "That sounds like a program with no freewill?"

ET: "We will catch up when you end this cycle"

Me: "Sounds like a 'KPI'!"

ET: "Did you read the terms and conditions?"

Me: .....

Dingbatt

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#141800 1-Jul-2008 09:53

Hey Argo:

I would like to endorse Masterpiece's comments above. I was trying to future-proof a couple of years ago with an HT Receiver. After spending a not insubstantial sum I have been caught out with with an hdmi system (1.1) that will not recognise 1080p and is not upgradeable. Since then I have given up trying to future-proof preferring to live in the now, with current but not bleeding edge (expensive) equipment.

I too lusted after the latest beauties from pioneer, but in the end decided not to pay twice as much for a 5-10% improvement in IQ. Having bought a panasonic instead I was able to get a Blu-Ray player and build an HTPC with the difference. I am now well on the way to replacing my 720p projector with a 1080p one (PT-AE2000).

I sit 4m from a 1024x768 42" plasma. It looked big for a start but now I am used to it, a Full HD 50" will do just fine.

Masterpiece: As far as bathrooms go, I also have the same problem but have decided I spend more time watching than washing.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

minimoke

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#141922 1-Jul-2008 15:31

In all this debate I think we sometimes loose sight of the source material. TV (and DVD’s) is only being broadcast in standard definition and is upscaled from there (with the one or two exceptions on Freeview).

So you essentially have a 576 image being blown up to 720/1080. This doesn’t mean you are getting a 720/1080 image – it means you are getting a cruddy image and your TV (or Freeview) is using complex maths to recreate a new image based on the original. A good TV will do a good job of this – but you are still not getting the fine detail you should expect from a true 720 or 1080 source picture (which is only available from Blue ray – or 4 tv shows on TV3 Freeview Terrestrial).

Going from a 576 image and having your TV recreate it to 720 may not be a big leap – but getting your TV to accurately recreate an image to 1080 could be a problem if it gets its math wrong. You might get lots of wee dots per square inch – but they might not be an accurate representation of the original picture. All you may end up with lots of wee dots of rubbish.

Even then, if you have blue ray and you sit too far away or too close to the TV you aren’t going to be getting the true value of your investment – except of course the TV retailer gets to eat meat that week.

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