posterization on SKY ?

happyhiker · 23-11-2009, 11:12 AM

Hi,

I've just upgraded my sky didgibox to a sky HD box and now I notice alot of posterization.
Image Posterization
It mainly happens on scenes where there is a plain wall in the background. The wall will have a weird pixel monster on it, sometimes moving.

But it also happens on faces and was really bad on the sky in top gear HD last night.

Any one know how to get rid of this ?

I have a Panasonic pwd6 SD panel fed via scart. I'm wantign to upgrade to a G10 but not if I'm goignm to get the same issue. Is this a problem with the flat screen tvs in general ? Plasmas? Panasonoics? Just me ?

I only get it on SKY broadcasts not freeview or DVD's etc.

*Ragnarok* · 23-11-2009, 1:17 PM

It's a similar effect to Posterization but it's more likely a H.264 artifact. It's one of the ways H.264 can compress more info out of the picture over mpeg2 before descending into macroblocks.
With H.264, on the whole it works and you usually don't notice it and you don't get macroblocks. When it becomes clearly visable, it's sign of bitrate starving in H.264.

paulr2006 · 23-11-2009, 1:47 PM

The only time I have ever seen it is on a poor (low bitrate) SD channel via Sky HD box, usually though SD is pretty good on most mainstream channels, never seen it on any HD channels using my Panasonic 50V10

themoron · 23-11-2009, 2:13 PM

I had my box installed yesterday and noticed this on Supernatural on Living (SD) via HDMI last night. I switched to Scart and it cured it but that's not an ideal solution really.

happyhiker · 23-11-2009, 2:29 PM

whats H.264 artifacts ?

Do Film 4do low bitrates ? I watched White Noise on film four and the effect was all over the place, but the fact I saw it on BBC HD, made me think it wasn't bit rate related ?

Still if you don't get it on a V10 then I presume you won't on a G10 and thats what I'm thinking of getting.

I do feed sky via scart though, and still get this, may be its jst by panel but the PWD6 panny is mean tto be superb, and in all other cases is.

Migman · 23-11-2009, 4:54 PM

Top Gear looked fine to me, bit rate should be 9mbps, not great but adequate, is your scart on a full RGB connection?

simon194 · 23-11-2009, 10:22 PM

Quote:

Originally Posted by Migman

Top Gear looked fine to me, bit rate should be 9mbps, not great but adequate, is your scart on a full RGB connection?

9 Mbps is the norm with the new, suposedly more efficient encoders.

happyhiker · 24-11-2009, 1:47 PM

yeah full rgb scart.
I think its partly the plasma. I was in Curries looking at their wall of 20 different sorts of plasma's and LCDs, when a colour gradation picture comes up (ie dark blue at the top getting lighter all the way down the screen) all of them displayed banding (ie little black lines where the screens can't cope with the gradual change of colour) but the posterization was worse on the Panasonics. The banding was on all of them.

*MunichMag* · 24-11-2009, 2:38 PM

I had this too when I switched to Sky HD at the start of the year. Really noticed on the opening credits of 24 when they showed a small picture of the character with the characters name against a black background. I fixed it by changing the settings on my plasma (Samsung), although it's a while ago and I can't remember exactly what I changed. Sorry can't be more helpful, but if you play with the settings on your plasma you should be able to get rid of it.

happyhiker · 25-11-2009, 10:23 AM

playing with the settings changes the posterization but also screws up the rest of the picture. Its really annoying me now, am I the only person getting this from Sky to Plasma, if its all plasmas or in the broadcast I'd think everyone had it.

Maybe its my cables ?

BOBBYBOB · 02-12-2009, 9:32 AM

Quote:

Originally Posted by happyhiker

playing with the settings changes the posterization but also screws up the rest of the picture. Its really annoying me now, am I the only person getting this from Sky to Plasma, if its all plasmas or in the broadcast I'd think everyone had it.

Maybe its my cables ?

I have just got a 42" G10, and use SKY HD, Posterization is terrible on some programmes, watched a recording of LIFE in HD last night & parts were terrible, seriously thinking of swapping the G10 for a Samsung LCD, and thoughts?

SHATNERSTACTIC · 02-12-2009, 10:36 AM

Quote:

Originally Posted by happyhiker

yeah full rgb scart.
I think its partly the plasma. I was in Curries looking at their wall of 20 different sorts of plasma's and LCDs, when a colour gradation picture comes up (ie dark blue at the top getting lighter all the way down the screen) all of them displayed banding (ie little black lines where the screens can't cope with the gradual change of colour) but the posterization was worse on the Panasonics. The banding was on all of them.

My understanding is that this stepped graduation you describe is also posterization and not banding, which is a seperate issue illustrated here. As commented earlier, most panels exhibit this posterisation effect. (cue avalanche of my panel doesn't replies!)

Having watched the HD broadcast of Life on my Panny V10 this week (the one with the Great Barrier Reef) posterization was not overtly noticeable to me (I wasn't analyzing for it) so with a degree of uncertainty I'd say the issue is the panel settings and not the broadcast here. Is it fair to assume nearly all posterization issues on a HD broadcast will be a panel issue given the greater bitrate of these channels?

happyhiker · 02-12-2009, 11:09 AM

Quote:

Originally Posted by BOBBYBOB

I have just got a 42" G10, and use SKY HD, Posterization is terrible on some programmes, watched a recording of LIFE in HD last night & parts were terrible, seriously thinking of swapping the G10 for a Samsung LCD, and thoughts?

I've just bought a G10 and comparing it directly to my SD panasonic plasma the banding is exactly the same on both. However I do not get it on my LCD. So I think it is a Panel Issue and I'm also considering swapping my G10 for an LCD

BOBBYBOB · 02-12-2009, 1:47 PM

I also watched 'LIFE' last night, recorded in HD, the underwater scene at about 13 mins, where the camera pans from the starfish towards the blue ocean is terrible, worst colour banding/posterization I have ever seen, no amount of fiddling with the settings would improve it.
Contacted Panasonic today about this, to be told, 'We do not look at forums, and no-one else has contacted us to say they have a problem like this with a G10'

Has anyone else been in contact with Panasonic? if so what did they say? If not, can I suggest you do!!!!
Seems to me Panasonic might be struggling here.

Siochain · 03-12-2009, 2:42 PM

I'm seeing exactly what the op has said. I would have thought it was my Pioneer Kuro but I didn't have these issues with an Amstrad hd box. The Amstrad was replaced with a pace hd box and it was noticeable straight away. Surely if this was the tv It would have been noticeable with the Amstrad HD box

*MunichMag* · 03-12-2009, 2:54 PM

Quote:

Originally Posted by lee12

My understanding is that this stepped graduation you describe is also posterization and not banding, which is a seperate issue illustrated here. As commented earlier, most panels exhibit this posterisation effect. (cue avalanche of my panel doesn't replies!)

My panel doesn't.....because I adjusted the settings to get rid of it......

Quote:

Originally Posted by lee12

Having watched the HD broadcast of Life on my Panny V10 this week (the one with the Great Barrier Reef) posterization was not overtly noticeable to me (I wasn't analyzing for it) so with a degree of uncertainty I'd say the issue is the panel settings and not the broadcast here. Is it fair to assume nearly all posterization issues on a HD broadcast will be a panel issue given the greater bitrate of these channels?

so.....no noticeable issues for me either.

*MunichMag* · 03-12-2009, 3:05 PM

Quote:

Originally Posted by Siochain

I'm seeing exactly what the op has said. I would have thought it was my Pioneer Kuro but I didn't have these issues with an Amstrad hd box. The Amstrad was replaced with a pace hd box and it was noticeable straight away. Surely if this was the tv It would have been noticeable with the Amstrad HD box

Not sure which box it is (either Sammy or Amstrad I think, but def not Pace as I have a pace would have remembered), but there was a thread or threads about contrast issues on one of them. If the boxes handle contrast differently, it could be that your Kuro (I'm very jealous) was set just right for the Amstrad box, and now you've swith to a Pace the panel settings don't match quite as well.

No idea what the settings are on a Kuro (I have a samsumg plasma), but thinking back, it could have been something as simple changing the mode from Move or Dynamic back to Standard that cured the posterization problem and then I changed the individual contrast, etc settings to get the best picture but without posterization.

You could also try playing with the contrast settings on the new Pace box and see if that makes any difference. Between the box and the panel you should be able to find settings that get rid of the problem.

Siochain · 03-12-2009, 3:41 PM

Quote:

Originally Posted by MunichMag

You could also try playing with the contrast settings on the new Pace box and see if that makes any difference. Between the box and the panel you should be able to find settings that get rid of the problem.

Thanks for the advice MunichMag. The Amstrad was originally swapped out due to the contrast issue causing white clipping and black crush. The thing is posterization doesn't appear to be visible on all HD broadcasts. I watched Mission to Mars in HD last night and it was Flawless, the same can be said for a variety of HD content i've viewed. Truly outstanding image. The first thing I done when I got the the pace was adjust the relevant tv settings and SKY box contrast to low or mid. No amount of tinkering with tv settings seems to get rid of this.

Apart from colour which as you know can't be adjusted by eye, contrast and brightness is set correctly on the tv for every other source and sky to an extent. I have all the picture enhancements and NR off. At present my belief is that this is a broadcast issue or perhaps the Pace box. But there hasn't been any reports of this being specific to a certain HD STB or even that the hd box was the issue. No other av source has this issue

I do not believe it's simply the tv and can't be fixed or anyone elses panel that has posted in the thread, There was a suggestion by one member that it was the tv's. But surely if the Panel itself was the cause this posterization would be visible across all sources. You yourself having fixed this indicates that it may be a combination of panel and stb settings and can be resloved. I just don't know. At the moment i'm watching Tombstone on sky HD and the picture is free of posterization.

tele1962 · 03-12-2009, 3:51 PM

Quote:

Originally Posted by Siochain

Thanks for the advice MunichMag. The Amstrad was originally swapped out due to the contrast issue causing white clipping and black crush. The thing is it doesn't appear to be visible on all HD broadcasts. I watched Mission to Mars in HD last night and it was Flawless, the same can be said for a variety of HD content i've viewed. Truly outstanding image. The first thing I done when I got the the pace was adjust the relevant tv settings and SKY box contrast to low or mid. No amount of tinkering with tv settings seems to get rid of this.

Apart from colour which as you know can't be adjusted by eye, contrast and brightness is set correctly on the tv for every other source and sky to an extent. I have all the picture enhancements and NR off. At present my belief is that this is a broadcast issue or perhaps the Pace box. But there hasn't been any reports of this being specific to a certain HD STB or even that the hd box was the issue. No other av source has this issue

I do not believe it's simply the tv and can't be fixed or anyone elses panel that has posted in the thread, There was a suggestion by one member that it was the tv's. But surely if the Panel itself was the cause this posterization would be visible across all sources. You yourself having fixed this indicates that it may be a combination of panel and stb settings and can be resloved. I just don't know. At the moment i'm watching Tombstone on sky HD and the picture is free of posterization.

As i have said in the G10 owners thread i wonder if the severity of the posturisation could be regional bit rates so some see it a lot worse than others?

For example very low bit rates such as ITV,bad posturisation and Blu-Ray DVD hardly noticeable.

Even HD broadcasts have variable bit rates,i wonder!!!!.

Siochain · 03-12-2009, 4:09 PM

Quote:

Originally Posted by tele1962

As i have said in the G10 owners thread i wonder if the severity of the posturisation could be regional bit rates so some see it a lot worse than others?

For example very low bit rates such as ITV,bad posturisation and Blu-Ray DVD hardly noticeable.

Even HD broadcasts have variable bit rates,i wonder!!!!.

Hey Tele
That my thinking at the moment. What I can say is that I haven't seen this on any other sources through the Kuro. Only Sky.

tele1962 · 03-12-2009, 4:12 PM

Quote:

Originally Posted by Siochain

Hey Tele
That my thinking at the moment. What I can say is that I haven't seen this on any other sources through the Kuro. Only Sky.

Hi Ya Siochain,

It does make you wonder.

Siochain · 03-12-2009, 4:16 PM

Quote:

Originally Posted by tele1962

Hi Ya Siochain,

It does make you wonder.

It certainly does. Tele your set is professionally calibrated isn't it. Have you seen posterization on your set.

tele1962 · 03-12-2009, 4:22 PM

Quote:

Originally Posted by Siochain

It certainly does. Tele your set is professionally calibrated isn't it. Have you seen posterization on your set.

I do get it from time to time but mainly on low bit rate broadcasts mind saying that it was quite bad on Top Gear hd the other week. Again though i think its down to the braodcast quality.

Siochain · 03-12-2009, 4:26 PM

Quote:

Originally Posted by tele1962

I do get it from time to time but mainly on low bit rate broadcasts mind saying that it was quite bad on Top Gear hd the other week. Again though i think its down to the braodcast quality.

I'm sure someone will tell me i'm wrong but as the 9g Kuro is not known to have issues with posterization. and i'm only seeing this with one source (Sky SD/HD).
It does lead me to think it's the broadcast.

happyhiker · 04-12-2009, 11:08 AM

I finally got to plug in my TV ariel last night, excellent SD quality on my G10 via the in built freeview BTW. So I was switching between sky and the ariel (as you do) to check the quality and I saw a bit of posterization on the Sky feed, switch to Freeview to get the exact same picture, no posterization.

So I am sure this is a Sky thing. Theres some setting that shows you the stength and quality of the sky feeds, mine have strong signal, but only 50% quality. I wondered if that had anything to do with it.

i think different screens handle the bad feed differently, with pannys not being the best. Though the G10 is better than my older panny.

tele-addict · 04-12-2009, 11:17 AM

If I am right in thinking what you are describing as Posterization. I occasionally have an unnatural affect that appears on walls and faces but this is not just confined to SKYHD images. The problem appears on DVD's as well. I have a 42" 1080i Panasonic Plasma and have tried all sorts of adjustments to try and improve the image but nothing works. I just put it down to being relatively old Tech now in comparison with some of the newer model panels.

happyhiker · 04-12-2009, 11:30 AM

Yes that sounds right. Its similar to Banding.

Banding is where you get colour graduation from dark to light and the panel can't display the subtle differences so you get lines, or steps of colour. Usually happens on Scenes of the sky, or underwater or on indoor scenes on back walls etc.

Posterization is a similar thing its where you get flat colours like a 1980's pop video. Or a Photo thats been dropped to 256 colours, but its still the inability to disp[lay graduation of colour.

On my Old panny I used to get Pixel monsters on back walls ( where you got a patch of colour that didn't quite match the wall, sometimes it flickered and moved. Lie to me in SD was a bad cause of this). But also on Faces sometimes, usually womens cheeks if they had shiny skin.

On My newer panny I don't get the pixel monster, but I still get a bit of banding. The banding doesn't bother me much, the posterization drove me mad.