Freesat greyscale problems

stanleyntl

Novice Member
I had a butcher's at both a Z1 46" and V20 42" in a local panasonic dealer's showroom. I set both to THX and ensured gamma was at 2.2.
Using freesat as a source (internal on V20, tuner box on Z1), I could still see subtle colour anomalies in a black and white film that could not be accounted for i.e. the familiar traces of purple and green that I have encountered before on my own G15 plasma. This can be quite severe on my own gear, acute purple and green striping on HD and SD programs.
e.g. The Wonders of The Solar System (BBC HD), I see marked purple and green bands in skies.

While Panasonic would like you to think this is source related, ie a poorly transcoded film (b/w CH5, Murder Ahoy), this type of error frequently pops up on SD broadcasts and even HD broadcasts!
Without doing further evaluation, I cant see whether it is better or worse than my own G15.

Phil Hinton has told me that greyscale is fine on the V20. I dont dispute his findings, presumably arrived at with DVD or BluRay source.
So why is there a problem with FreeSat source as witnessed by me today?

Are there any other eagle-eyed members who have seen this phenomena?

I have another member ********, telling me that Panasonic plasma can not render perfect greyscale, unlike the Pioneer Kuros which use dithering.
 

Phil Hinton

Editor
Staff member
I had a butcher's at both a Z1 46" and V20 42" in a local panasonic dealer's showroom. I set both to THX and ensured gamma was at 2.2.
Using freesat as a source (internal on V20, tuner box on Z1), I could still see subtle colour anomalies in a black and white film that could not be accounted for i.e. the familiar traces of purple and green that I have encountered before on my own G15 plasma. This can be quite severe on my own gear, acute purple and green striping on HD and SD programs.
e.g. The Wonders of The Solar System (BBC HD), I see marked purple and green bands in skies.

While Panasonic would like you to think this is source related, ie a poorly transcoded film (b/w CH5, Murder Ahoy), this type of error frequently pops up on SD broadcasts and even HD broadcasts!
Without doing further evaluation, I cant see whether it is better or worse than my own G15.

Phil Hinton has told me that greyscale is fine on the V20. I dont dispute his findings, presumably arrived at with DVD or BluRay source.
So why is there a problem with FreeSat source as witnessed by me today?

Are there any other eagle-eyed members who have seen this phenomena?

I have another member ********, telling me that Panasonic plasma can not render perfect greyscale, unlike the Pioneer Kuros which use dithering.
Out of the box you are going to get differences in the greyscale, it will not be correct. If it is well out in some areas then you will clearly see colour casts on screen. THX mode should give a good result, but like I say in every review, it is a catch all setting that is not perfect and can vary quite a bit from THX TV to THX TV. it is better than most out of the box settings, but it's not perfect. Far from it.

Greyscale will not cause colour fringing. This can be caused by a few issues but most likely phophor trailing or contouring. This is a well documented issue with the Panasonic screens which can be seen by some users much like the flicker issues seen by some and not seen by others. I see more fringing and phosphor trailing on a Pioneer (not calibrated and in bright modes) than on a calibrated Panasonic. I also see some slight banding on the Panasonic (with broadcast) but this in my opinion is better than the plaster-like faces on an LCD. Only saw one small instance of the floating blacks and again better than a full screen of floating blacks and everything else on most LCDs. Varies from person to person, from screen to screen, and every TV, no matter the technology used, will have it's issues and traits. The Kuro for example has poor chroma upsampling, buzzing, banding, retention and in some cases and presets - picture tearing and crushed blacks. You see even a reference screen can be full of issues if you go looking for them, it's whether they affect the overall aim or not of the TV and what other strong points that set may have. We have not dumped the LX5090 as a reference yet, for good reason.

Again as documented the latest Panasonic's are not as good as our reference LX5090 and will be slightly further again behind the KRP, but you can't buy a Pioneer new anywhere these days, so in terms of what is available the Panasonic is the best option IMHO if you must have a new TV now. But again, demo, demo, demo. It's your money and your choice so weigh up what you will use it for and then use that to narrow down your search. This is where technical reviews that go looking for issues can help.

Without seeing your G15 in the flesh I wouldn't like to guess what is wrong, but it sounds like a mix of the issues above that you can clearly see. There is no such thing as the best TV as every make and model has its strengths and areas where it will perform poorly. Its finding the best balance for you and your needs, against what is available. For me, I just couldn't live with the vast majority of LCD and LCD LED screens due to clouding, poor viewing angles and in most cases huge colour inaccuracies. But I do know that those TVs will appeal to others because their needs are different to mine. Which is why my advice will always be as balanced as possible when taking into consideration where a certain model or technology will be used, offset against the performance critia that people are looking for.

If you take for example the latest LG TVs against the Panasonic's. The Panasonic has a clearly better black level as the LG is not up to competeing here. However the LG has better calibration controls to fine tune the image to the standards. The LG doesn't suffer from floating blacks and I have yet to see any Phosphor trailing or fringing on their panels. However, the LG has pretty excessive Image retention when compared to the Panasonic and it has higher instances of colour banding. Both have THX mode that measures quite well and both offer good colour reproduction out of the box in that mode. Both have about the same lag time for gaming. So, as you can see even between two plasma screens there can be instances where you will have to weigh up the plus points and negatives to find what you can live with and what suits your needs. I know a few who have returned their LGs after seeing that the black levels are poor even though the set is strong in other areas. There are those who have returned Panasonic sets because of issues they couldn't live with. I can think of only two LCDs that could come close to competeing with either of those sets though, if you are looking for accuracy.

The reviews are a tell it all exercise that will give you all the plus and minus points we find, along with accurate measurements. But it is for information only and is down to the reader to use it against their requirements. (We measure greyscale and calibrate it from a calibrated pattern generator, not a source. It can be that a source player has a greyscale that can be pretty far out - rare but it can happen FYI).
 

stanleyntl

Novice Member
Your valued opinion is much appreciated Phil.
Does colour fringing vary significantly from one Panasonic model to another?
 

Phil Hinton

Editor
Staff member
Your valued opinion is much appreciated Phil.
Does colour fringing vary significantly from one Panasonic model to another?
It's a mix of the technology used and personal perception of the issue. Some see it on everything and it can ruin the experience, some see it now and again, some don't see it at all. There are cases where it can be worse on one model from one manufacturer than from another and is therefor seen more by those who normally maybe wouldn't notice it. It is a bit like the single chip DLP rainbow effect that some see and others don't as well as some models using technology to reduce the instances of it. But it can also rear up with certain material, like a B&W film or something like Sin City. Add in an incorrect Greyscale with that type of material and the problems can seem worse again. That is a rather simplified answer but I hope it helps.
 

stanleyntl

Novice Member
It's a mix of the technology used and personal perception of the issue. Some see it on everything and it can ruin the experience, some see it now and again, some don't see it at all. There are cases where it can be worse on one model from one manufacturer than from another and is therefor seen more by those who normally maybe wouldn't notice it. It is a bit like the single chip DLP rainbow effect that some see and others don't as well as some models using technology to reduce the instances of it. But it can also rear up with certain material, like a B&W film or something like Sin City. Add in an incorrect Greyscale with that type of material and the problems can seem worse again. That is a rather simplified answer but I hope it helps.
That is helpful, strange you should mention Sin City because when broadcast on BBC2, thru a previous Viera S10. That was outstanding IMHO. Like you said, it could no doubt vary badly between one model and the next!
 

Phil Hinton

Editor
Staff member
That is helpful, strange you should mention Sin City because when broadcast on BBC2, thru a previous Viera S10. That was outstanding IMHO. Like you said, it could no doubt vary badly between one model and the next!
Well another thing to consider is that broadcast material should never be used as test material for colour reproduction etc. It can vary too much in terms of transmission quality. Look at Channel 4 at the moment. There seems to be some issue with their transmissions (or masters) when it comes to colour reproduction and one issue I have seen recently is some form of chroma delay or sample error, not quite sure exactly what it is, migh even be a strange compression error, but you can see excessive banding and colours like reds, pulsating and flickering. Seen this on a few TVs and even our reference so its a Channel 4 issue, was particularly bad on location, location. Remember that all broadcast material is heavily compressed, even the HD channels can look pretty bad for artefacts like banding. However, I will also stress that it is not always compression that can affect broadcast quality. Strange issue with C4 and I have yet to find out exactly what it is. Stick to good sources for picture evaluation. If in doubt get the test patterns out (But also remember that the source of the test patterns may be compromised LOL).
 

tele1962

Distinguished Member
Phil it's been mentioned by a few on here. Somebody said that it was an encode fault on certain C4 broadcasts and they were working on a fix.

Just a quick question Phil. Pattern generators are they expensive and where can i purchase one?
 
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Phil Hinton

Editor
Staff member
Just a quick question Phil. Pattern generators are they expensive and where can i purchase one?
Best budget one I have seen is the CalMAN DSG which will set you back about a grand. Next up are the Sencore ones we use and they start at about £2.3k. Really only worth it to professionals and review sites. Most sources like a good quality BD player and DVE will be fine for most.
 

tele1962

Distinguished Member
Best budget one I have seen is the CalMAN DSG which will set you back about a grand. Next up are the Sencore ones we use and they start at about £2.3k. Really only worth it to professionals and review sites. Most sources like a good quality BD player and DVE will be fine for most.
Wow :eek: I think i will stick with my AVCHD test patterns and DVE disc.:D
 

Insanity202

Distinguished Member
Phil it's been mentioned by a few on here. Somebody said that it was an encode fault on certain C4 broadcasts and they were working on a fix.
That was ME :D
They told me a fix was on the cards and they were looking into the issue, but tbh that was before xmas. Still no fix. Come dine with me is a top culprit to show red 'shudder/flicker'. Yet on other shows its fine. :confused:
Maybe its something to do with there shows are not recorded in native HD but is SD poorly upscaled?
 
That was ME :D
They told me a fix was on the cards and they were looking into the issue, but tbh that was before xmas. Still no fix. Come dine with me is a top culprit to show red 'shudder/flicker'. Yet on other shows its fine. :confused:
Maybe its something to do with there shows are not recorded in native HD but is SD poorly upscaled?
no because the reds are all over the place on CDWM via Sky+ on my CRT set :hiya:
 

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