What is a "poor source"

AirCooledHeaven

Standard Member
I'm agonising over whether to go for a 50hz or 100hz TV, I understand this is a subjective decision, but one I've still been unable to make, despite looking at many 50/100Hz sets.

I can find one set that looks great in one store and yet looks awful in another. I'm coming to the conclusion that it's impossible to make an objective comparison when places like Currys/comet/etc clearly have no idea how to display sets to demonstrate their true potential.

Looking through this forum for advice I see comments like "100hz/digital processing chews up a poor source (sky)" I don't have sky so I'd like to understand what a "poor source" really is. Is freeview a "poor source"? My new set will mainly be used for freeview, so if this is likely to be "chewed up" by 100Hz/digital processing then my decision becomes easier.

Thanks
 

NicolasB

Well-known Member
"Poor source" is (IMO! :) ) a term invented by people who have spent too much money on a poor quality screen in an attempt to make themselves feel better. Certain types of display (LCD TVs seem to be particularly prone to this) tend to look very good if you feed them a high-quality progressive-scan signal from a DVD player, but look like crap when you use them to watch Sky. People don't want to admit to themselves that they've just spent £5000 on a "bad" TV, so they tell themselves that the TV is great and the problem is with Sky.

IMO this isn't true - it's mostly the fault of the poor deinterlacing electronics in the screen.

To be fair, there's really no such thing as a "good" deinterlaced signal. The reason you get a good picture from prog scan DVD is that the thing you're watching was generally shot on film, and is therefore inherently progressive - it actually can be converted to a progressive picture correctly. With something inherently interlaced (shot on video) there simply isn't any definitively "correct" deinterlaced picture, and any attempt to produce one will sometimes look bad, now matter how sophisticated a method is used.

For this sort of source a display that is inherently interlaced itself (i.e. a 50Hz direct-view CRT) is likely to produce the best results, because it's displaying the signal as it is intended to be displayed.
 
B

Bombdogs

Guest
Sounds like one of my quotes. They key concept to understand is that of 'bandwidth' - the more detailed a scene is the more bandwidth required to transmit it. SKY compresses the f*** out of its signals, in order to squeeze 140 shopping channels, 347 sex-cam channels & 939 phone-in quiz channels onto its platform. This compression really hits detailed scenes & you can see 'artifacts' around the edges of objects, in much the same way that you can see a haze around objects in poor jpeg images on the web. A normal CRT softens these haze effects due to the way it displays pictures. However digital processing assumes this haze is an integral part of an image & tries to sharpen it up, really making a 'feature' out of it. Not ideal.

Other poor sources I have had personal experience of :- PlayStation 2 & any RF input.

A good source would be a DVD player - it outputs a crystal clear picture with no compression at all - the digital processing is designed to work on this sort of picture & genrally does it's stuff very well.

PMF
 

AirCooledHeaven

Standard Member
Bombdogs said:
Sounds like one of my quotes. They key concept to understand is that of 'bandwidth' - the more detailed a scene is the more bandwidth required to transmit it. SKY compresses the f*** out of its signals, in order to squeeze 140 shopping channels, 347 sex-cam channels & 939 phone-in quiz channels onto its platform. This compression really hits detailed scenes & you can see 'artifacts' around the edges of objects, in much the same way that you can see a haze around objects in poor jpeg images on the web.

PMF
So how much is Freeview compressed compared to sky? 50%, 25%???
 
N

nig28

Guest
Hi

The question "a good sourse" would depend on the context it was said in.

If you are viewing TVs in Comet/Currys, they may get their signal, via rf/aerial lead - which is a poor sourse because it will pick up interference along the way.
And if you are viewing in your own home with a poor analogue signal this would be classed as a poor sourse.
With a good aerial freeview should be generally a good sourse - on a 28" screen
If you are viewing on a 36"+ screen thenanything which is poor can be seen.

Nigel
 
B

Bombdogs

Guest
AirCooledHeaven said:
So how much is Freeview compressed compared to sky? 50%, 25%???
Unfortunately I've no personal experience of freeview - I'm sure it'll be compressed to some degree, but I've no idea how much & whether this leads to visible artifacts. I'd imagine it to be better than Sky tho - it can't get any worse :eek:

PMF
 

matJ

Standard Member
The difference I noticed when looking at 50hz and 100hz TV's is that the 100hz could not display the colour white as well as the 50hz. It would look slightly dirty, and not as bright, even with contrast and brighness set to max. There is less flicker though!!
I've just ordered a Sony 28" 50hz rather than a Panasonic 28" 100hz simply because the sony IDTV is more reliable and the Panasonics have a turning off problem when using q-link. Would have got the 100Hz Panasonic if these where not issues.
 

Will Scarlet

Well-known Member
Bombdogs said:
However digital processing assumes this haze is an integral part of an image & tries to sharpen it up, really making a 'feature' out of it. Not ideal.
Quite correct. It is not that they process the information badly, it is that they assume, as Bombdogs says, that the crap in the signal is part of the picture and enhance it. Instead of stating stuff like, "people don't want to admit to themselves that they've just spent £5000 on a "bad" TV", you should be asking WTF am I paying Sky for? Talk about shooting the messenger. It's the signal not the T.V., feed it a decent signal and..... that's a fact, not an excuse!:lesson:
Slightly off-topic, but why on earth people are getting excited about Sky HD I have no idea. Given their record so far in broadcasting it'll be the absolute lowest quality HD signal they can get away with that'll be broadcast. Granted it'll be better than what they broadcast now, but that wouldn't be too hard would it? and they'll have you paying through the nose for it.
 

Kalos Geros

Active Member
Actually, I'd recommend people to get a decent low cost 16:9 50Hz set for watching SKY and freeview and a decent not overly expensive home cinema projector for progressive DVD - the two combined wouldn't set you back any more than a 42" SD plasma which is I'm starting find out, is way to small to enjoy cinematic experience...I'm curently investigatng into such a combination...
 
M

mjr600

Guest
Own brand and budget I wouldn't touch, always go for HP or Heinz with red, Daddies is the king of Brown.

Sorry, I've been drinking...
 

Will Scarlet

Well-known Member
Really? I'd never have guessed. :D Got to be Heinz IMHO.
 

NicolasB

Well-known Member
Will Scarlet said:
It is not that they process the information badly, it is that they assume, as Bombdogs says, that the crap in the signal is part of the picture and enhance it. Instead of stating stuff like, "people don't want to admit to themselves that they've just spent £5000 on a "bad" TV", you should be asking WTF am I paying Sky for? Talk about shooting the messenger. It's the signal not the T.V., feed it a decent signal and..... that's a fact, not an excuse!:lesson:
The fact that it is the TV and not the signal is precisely the point I was trying to make. Yes, a Sky signal is poorer quality than a DVD signal, but this does not explain why many expensive flat-panel devices look as bad as they do with Sky. The difference is the result of the DVD player correctly deinterlacing inherently progressive material and the screen not introducing deinterlacing errors of its own.
 

Trending threads

Top Bottom