Posterization/False Contouring

scottthehat

Distinguished Member
Hi just wondering if any one notices it on samsung plasmas, the last couple of nights i watched season of the whitch(nicolas cage) on sky hd and noticed a couple of times when dark scenes that if the turned or moved a body part fast i got a green and red line(if i rewound it it was gone)

so i tryed the end of alien vs predator(sky hd) which is quite a dark misty picture and nothing at all,
but last night whilst flicking channels i had ncsi (sky 1 hd) and noticed it a couple of times
does it sound like Posterization/False Contouring or siomething else.
can be anoying will have to try some games and bluray.
 

smpearce22

Active Member
Certainly sounds like it, Im particularly sensitive to it too, but its just a limitation of Plasma technology and how it works.

You'll find its a lot worse on UK Tv broadcasts because the Bitrate its transmitted at from the source is generally quite low, even in HD.

The general rule of thumb I've experienced is that false contours get more pronounced as the quality of the source is lowered.

For example if you watched the same Movie on Blu-Ray, with a prestine transfer at a nice high Bitrate theres a good chance the false contours would be negligable or gone altogether.

Of course thats not going to be true in EVERY instance, but its a starting point.
 

Scooby2000

Distinguished Member
Hi just wondering if any one notices it on samsung plasmas, the last couple of nights i watched season of the whitch(nicolas cage) on sky hd and noticed a couple of times when dark scenes that if the turned or moved a body part fast i got a green and red line(if i rewound it it was gone)

so i tryed the end of alien vs predator(sky hd) which is quite a dark misty picture and nothing at all,
but last night whilst flicking channels i had ncsi (sky 1 hd) and noticed it a couple of times
does it sound like Posterization/False Contouring or siomething else.
can be anoying will have to try some games and bluray.
Sounds like it, though Samsungs have far less than Panasonics. Dont really see it on my D6900, maybe once or twice but it is very content dependent.
 

scottthehat

Distinguished Member
thanks guys will just have to get used to it as i love the tv.
its a shame as my sharp lcd produces a wonderfull picture and never once had one problem i could moan or worry about, now with plasma i see that and worry about image rention and burn:facepalm:
and thats good that its more content with lower bitrates and it did make me think because when i rewound it it was gone from the same bit.
 

smpearce22

Active Member
thanks guys will just have to get used to it as i love the tv.
its a shame as my sharp lcd produces a wonderfull picture and never once had one problem i could moan or worry about, now with plasma i see that and worry about image rention and burn:facepalm:
and thats good that its more content with lower bitrates and it did make me think because when i rewound it it was gone from the same bit.

Yeah, I know exactly what you mean.

When I made the change from my trusty old Sony LCD to Plasma I found the difference quite jarring.

I couldnt decide if it was better, worse, or just different.

A year later I am solidly sitting in the Plasma camp as its overall a more natural image.

However I think its far to say that Plasmas have their quirks and are generally higher maintenance as you feel the need to wrap them in cotton wool to protect the investment....certainly until you get past the 800-1000hr mark.

.....but its worth it :thumbsup:
 

scottthehat

Distinguished Member
Yeah, I know exactly what you mean.

When I made the change from my trusty old Sony LCD to Plasma I found the difference quite jarring.

I couldnt decide if it was better, worse, or just different.

A year later I am solidly sitting in the Plasma camp as its overall a more natural image.

However I think its far to say that Plasmas have their quirks and are generally higher maintenance as you feel the need to wrap them in cotton wool to protect the investment....certainly until you get past the 800-1000hr mark.


.....but its worth it :thumbsup:
so true.
800hrs :eek: man im on about 115hrs so lots of cotton wool still to be used.:(
 

arenaman

Moderator
Just to throw a spanner in the works about this being a plasma thing I get posterization on my ES8000 LED and had it on my D8000 LED but never saw it on my D6900 plasma. This only happens whilst watching Sky HD. I've had SKY out a few times and they showed me how to minimise it (contrast lower, dynamic contrast high) but it's still not right.

Is it the TV's fault for failing to deal with the colour gradient or is it just the TV exposing Sky's poor feed that they're pumping out these days????
 

scottthehat

Distinguished Member
arenaman said:
Just to throw a spanner in the works about this being a plasma thing I get posterization on my ES8000 LED and had it on my D8000 LED but never saw it on my D6900 plasma. This only happens whilst watching Sky HD. I've had SKY out a few times and they showed me how to minimise it (contrast lower, dynamic contrast high) but it's still not right.

Is it the TV's fault for failing to deal with the colour gradient or is it just the TV exposing Sky's poor feed that they're pumping out these days????
Weird never noticed it on my lcd but that might be because it was 19" smaller. But i will keep my eye on it.
 

arenaman

Moderator
Weird never noticed it on my lcd but that might be because it was 19" smaller. But i will keep my eye on it.
Cheers, this is becoming a right pain for me now, I'm convinced it's to do with the signal strength and quality as it happens always when they're low (50% region) which they regularly drop to.

I've had a Sky "specialist engineer" out who insists it's nothing to do with strength and quality (unless they dipped to 20% and below) Strange I can physically see the correlation between the low strength/quality and the posterization but it's being dismissed as irrelevant. :(
 

Scooby2000

Distinguished Member
Just to throw a spanner in the works about this being a plasma thing I get posterization on my ES8000 LED and had it on my D8000 LED but never saw it on my D6900 plasma. This only happens whilst watching Sky HD. I've had SKY out a few times and they showed me how to minimise it (contrast lower, dynamic contrast high) but it's still not right.

Is it the TV's fault for failing to deal with the colour gradient or is it just the TV exposing Sky's poor feed that they're pumping out these days????
Id go with the latter.
 

Nicholars

Banned
I would have thought the signal would just cut out or get artifacts on the screen such as squares etc.... The bitrate varies on different channels and programmes.... Some will have really good bitrate and some relatively poor bitrate.

I don't think that the banding would change depending on the signal level because it is still the same bitrate signal.... It would either be there or not and if the signal is too low you would see blocking or image cut out.
 

VierraFan

Active Member
Correct. If signal is too low, it is manifested as squares on the screen.

Yes, banding is a problem on plasmas, while it doesn't happen on LCD-s. LCD-s are mostly true 8 bit displays, except those with TN matrices that are 6 bit and are also using dithering (sometimes called FRC to hide that). My LCD monitor has eIPS matrix which is also 6 bit, but dithering used on it is different than on plasma and there is also no banding. As I shown in two threads, Panasonic plasma screens are effectively 3-5 bit displays (depending on mode). Maybe 2500ffd models are better, but I can't tell without making the same tests. So, dithering and banding are visible sometimes

If someone is willing to experiment and has DSLR with manual video mode, we can determine how it is on Samsungs and LG-s
 

arenaman

Moderator
Id go with the latter.
I keep hearing this, so my TV's not broken, I can take that as a morsel of consolation but it doesn't solve the problem does it?
 

scottthehat

Distinguished Member
Correct. If signal is too low, it is manifested as squares on the screen.

Yes, banding is a problem on plasmas, while it doesn't happen on LCD-s. LCD-s are mostly true 8 bit displays, except those with TN matrices that are 6 bit and are also using dithering (sometimes called FRC to hide that). My LCD monitor has eIPS matrix which is also 6 bit, but dithering used on it is different than on plasma and there is also no banding. As I shown in two threads, Panasonic plasma screens are effectively 3-5 bit displays (depending on mode). Maybe 2500ffd models are better, but I can't tell without making the same tests. So, dithering and banding are visible sometimes

If someone is willing to experiment and has DSLR with manual video mode, we can determine how it is on Samsungs and LG-s
i had 2 lcds with major banding.
 

VierraFan

Active Member
Well, I didn't say that it isn't possible to get banding on LCD-s, for various reasons:

- cheaper TV's have 8 bit color managemet, which can descrease number of possible levels from 255 to less and produce banding. It's surely true on the PC - moving saturation, cotrast, gamma etc sliders from default position on graphic card driver will produce banding, because number of possible levels is decreased due to the rounding of those values to nearest integer value. However, it's not happening on Philips LCD TV in my parents' flat - whether color management is more than 8 bit, or these things are performed in analog domain (because LCD screen is actually an analog device - cells are driven by voltage, while plasma is purely digital - each cell can be only on or off)
- uniformity of backlight (LED mostly)
- various dynamic contrast options that are raising brightness on dark scenes, making imperfections in source material more visible (shadows are more compressed, so if you make shadows brighter, it is becoming visible). The same on my UT30 plasma - it has undefeatable dynamic contrast, known as "floating blacks issue"
- etc etc

However, if LCD matrix is 8 bit, it surely doesn't produce visible banding by itself - there must be some other reason for banding
 

arenaman

Moderator

Scooby2000

Distinguished Member
I keep hearing this, so my TV's not broken, I can take that as a morsel of consolation but it doesn't solve the problem does it?
Im not an expert but experiance with panasonics shows whats being broadcast has an effect, quite a big one. Though improved Panasonics still dont seem that great with DFC.

Only way to solve your problem is to get another set but Id check the same feed/material on another set first.
 
Last edited:

panman40

Distinguished Member
Fair enough, it just read like that.
Edge lit LCD's suffer the vertical banding, As for Sky Signal Strength / Quality it would need to be very poor to cause an issue, ie you would get proper pixellation which would be very obvious or the signal and resulting Pic would dissapear altogether briefly.

If you want to try and improve the signal anyhow get a new LNB cheap off ebay and an Analouge style Sat meter and have a tiny tweak. I did re done my own setup 18 mths ago and get 95/95% but as the signal is digital it wont make any difference :)
 

arenaman

Moderator
Im not an expert but experiance with panasonics shows whats being broadcast has an effect, quite a big one. Though improved Panasonics still dont seem that great with DFC.

Only way to solve your problem is to get another set but Id check the same feed/material on another set first.
I've checked it on 3 separate sets (2 x LEDs and an LCD) had a new sky box and tried it on the multiroom box, all the same. I've just tuned in the freesat and am trying to monitor the HD quality on that, if it doesn't do it on there then it has to be the feed from sky.

And don't mention DFC, relegation day today :suicide::( :laugh:
 

arenaman

Moderator
I've been watching The Addams family on 4HD both on Freesat amd Sky HD, I'm getting Posturisation on Sky HD when the signal strength drops below 90%, really bad when it drops towards 50. No problem at all on Freesat. My sky box is an Amstrad DRX 890 which is apparently quite decent. I'm running out of options now
 

panman40

Distinguished Member
I've been watching The Addams family on 4HD both on Freesat amd Sky HD, I'm getting Posturisation on Sky HD when the signal strength drops below 90%, really bad when it drops towards 50. No problem at all on Freesat. My sky box is an Amstrad DRX 890 which is apparently quite decent. I'm running out of options now
Really cannot make that out at all then :confused:. Definately should not make an iota of difference to posterisation.
 

Nicholars

Banned
Hmmm well 2 people just said that it is not to do with signal level lol. It might just be that you are noticing it because you are looking for it and it is just due to the bitrate being used on the channel....

If anything your 8000 series LCD should not have banding because I have used a D6100 and a D6530 and very rarely noticed any banding... They are either 8 bit or 10 bit panels so they should be fine... As Vierrafan said you should only get bad banding on plasmas and cheap panels such as TN panels.
 

Nicholars

Banned
MMM banding can be used to describe the vertical full screen type or the colour banding type. I meant colour banding like you are showing. That does look quite bad hmmm.
 

arenaman

Moderator
MMM banding can be used to describe the vertical full screen type or the colour banding type. I meant colour banding like you are showing. That does look quite bad hmmm.
Got ya :laugh: what about horizontal banding? you missed that ;)

This doesn't happen all the time but I see it daily and it has various degrees of severity (picture is about the worst I've seen) but you can probably see why it's bugging me. Brand new TV, brand new dish, brand new box, everything checked and double checked what the hell do I do next?
 

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