LCD TV's 42inch/46inch

eitai2001 said:
Thats my point ... but there is no downscalling involved because the tv can handle the 540 lines at a time ... the same as the trolley could accommodate 500 apples at a time ... and the trolley comes back for the second load so quickly it appears that all the apples are on the trolley as an optical illusion.
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If the positions of those apples overlap you will not create the illusion of 1000 apples, but 500. In the case of a trolley that can only handle 600 apples you have to downscale 1000 apples before you can put them onto the trolley. What appears on your trolley will only be 600 apples.

Analogue TVs do not have discrete pixels. They just squash whatever you put into them into the number of lines that the gun scans. That is why when you input a 16:9 signal into a 4:3 TV and put the TV into 16:9 mode it does not have to do any processing, it can just scan the full number of lines over a smaller area of the screen. On a digital display there has to be downscaling.

You are not supposed to overlap lines when you interlace the output.
 
Ya ... I suppose that makes sense ... but then remains the question ... why did they ever come out with 1080i ... or was that just for the old analogue CRT HDTV's t 100hz?
Unless it was for the CRT and got sucked into the LCD ... there is not point for 1080i because on a 1366x768 lcd ... it can only support 720p ... so why even bother with 1080i ... and on a 1920x1080 lcd ... why bother with 1080i because you can accept 1080p ... so whats the point of 1080i.
 
because 1080p requires twice as much bandwidth as 1080i, more processing, more expensive hardware!!!
 
eitai2001 said:
Just by the way ... 1366x768 DOES DISPLAY 1080i ... in fact 720p is better than 1080i. If you understand the concept of 1080i, you will know that it is interlaced, meaning for every 1 frame ... it has to show the image twice. First all the odd numbered lines and then all the even numbered lines.
So in this way ... the TV pushes the first 540 vertical lines in the first picture and then then next 540 lines in the next picture ... it does this so quickly though that it seems like a constant picture. A tv with a resolution of 1366x768 is perfectly capable of displaying 1080i because it has a resolution of 768 vertical lines, and it only needs 540 for 1080i.
720p is better because it shows all the lines in 1 go, and there are more vertical lines then just 1 shot of 1080i.
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The best HD format is the 1080p (the only real HD)
 
eitai2001 said:
Agreed on a full HD panel ... but we aren't speaking about full HD panels ... we are speaking about 1366x768 panels ... but in this case it also depends what the signal is ... for sport 720p is much better ... it also boils down to personal preference.
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No. p is better than i for fast moving footage, but 720p is not better than 1080i automatically.

A 1366x768 panel is perfectly capable of displaying a 1080i res the same as it would display on a 1080p screen
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Cr@p. you are confusing de-interlacing and downscaling. A 1080i signal on a 720p panel will be downscaled to 720 lines and de-interlaced to make it progressive. On a panel that is natively capable of displaying 1920x1080, the signal will only be de-interlaced.

... except the 1080p screen upscales it from 1080i to 1080p thereby making it better on a 1080p screen.

1080i is not the same as 1080p ... 1080p is all 1080 lines in 1 pass of 1/30 second
A 1080i image is 2 passes of 540 lines in 1/30 second ... thereby immitating 1080 lines, but instead of giving you 1080 lines in 1 go every 1/30 of a second, it breaks the picture into 2 parts and displays 540 lines every 1/60 of a second thereby equating to 1080 lines every 1/30 of a second ... and your brain then takes the two images of 540 lines and sticks them together to make a 1080 picture in your head.

A tv with a resolution of 1366x768 is more than capable of displaying 540 lines ... and so to make it seem as though the resolution is 1080p ... the TV displays the 540 lines every 1/60 of a second to give you 1080 lines in 1/30 of a second as opposed to the full 1080 lines every 1/30 of a second.

And no offence but if this still doesn't make sense to you ... go practice some maths followed by some logic.
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Please stop writing about stuff you don't fully understand.

I do however agree that a 1080p signal can obviously not play as 1080p on a 1080i screen.
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There is no such thing as a 1080i screen (well not LCD or Plasma - it is possible for CRT, but I don't think that is too important for this discussion) All panels are progressive by nature.
And just by they way ... they don't call a screen with a resolution of 1366x768 a 1080i screen for the fun of it.
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No they don't. They don't call it it that at all. Don't confuse signal input with screen resolution.

If I'm wrong ... then you better phone Sony, LG, Samsung, Toshiba, Philips, BenQ, Panasonic, Hitachi, PVision, Polaroid, JNC and every other manufacturer out there and tell them that the specifications in their manuals are wrong and that their TV's actually can't display 1080i.
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You're wrong and they don't. They show the signal capability, not the screen resolution.
 
arf9999 said:
There is no such thing as a 1080i screen (well not LCD or Plasma - it is possible for CRT, but I don't think that is too important for this discussion) All panels are progressive by nature.
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Agree with all your points but could you please elaborate on ^ that one please.
 
CRT (Cathode Ray Tube) Screens (mostly) work in an interlaced manner, where each alternate line is scanned. Due to the manner in which phosphors glow, the screen could be built up with two fields per frame. LCD screens and Plasmas are pixel based displays, so it is possible to refresh the entire frame at once. Thus, 1080i which has some advantages in terms of signal bandwidth and processing power requirements, has to be de-interlaced before it is displayed. (Actually all interlaced video has to be de-interlaced before it can be displayed on a panel TV, including normal SD television broadcasts.).
 
I have heard about this ... and have heard that all interlaced signals get converted to progressive ... which I suppose is the same as de-interlaced.
I understand now that the 540 gets converted to 360 and added together to make 720 ... but what I said about interlaced signals getting shown every 1/60th of a second or twice every 30 seconds ... is not crap ... and you can find it on the internet.
When ever the reps from Sony or Samsung come, they call it a 1080i screen ... so thats where I got that from.
Also ... samsung puts a sticker that says they display 1080i on their tv's .. or at least they used to ... can't remember if they still do.
 
dude, just look at the pretty picture and smile!!!
 
eitai2001 said:
but what I said about interlaced signals getting shown every 1/60th of a second or twice every 30 seconds ... is not crap
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Each full frame is refreshed 30 times a second, each field 60 times a second. I'm not sure about LCD and plasma, but for CRTs this was actually 29.97/59.94 for NTSC and 25/50 for PAL.

eitai2001 said:
When ever the reps from Sony or Samsung come, they call it a 1080i screen ... so thats where I got that from.
Also ... samsung puts a sticker that says they display 1080i on their tv's .. or at least they used to ... can't remember if they still do.
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It is a marketing gimmick. It looks impressive if you say your product supports 1080i even though there is no real benefit to the consumer because the screen's resolution is 720p.
 
Damn marketing gimmicks ... that and the 99 story ;)
I read it on some website somewhere that that is the timing ... or at least rounded off timing for interlaced. But it was an american site ... so was probably that NTSC 29.97 bla bla timing. Pal like you say is prob 25/50.
I also read that interlaced gets converted to progressive on LCD's so like mentioned earlier ... (540 /2) * 2 = 720 and then the tv shows that in 1 go ...

Another question ... why did they bother with a resolution of 768 if it only uses 720 ... never figured that one out.
 
They must be scaling 720 up to 768. Why is it 768? Maybe they can make them with that many lines for essentially the same cost and it looks good on your marketing material if you can say you have 768 pixels. It's more than 720.
 
noxibox said:
They must be scaling 720 up to 768. Why is it 768? Maybe they can make them with that many lines for essentially the same cost and it looks good on your marketing material if you can say you have 768 pixels. It's more than 720.
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It's a holdover from XGA PC resolution. Most of these TVs can accept a PC input and in order to claim XGA resolution, they need to display at least 1024x768.
 
noxibox said:
They must be scaling 720 up to 768. Why is it 768? Maybe they can make them with that many lines for essentially the same cost and it looks good on your marketing material if you can say you have 768 pixels. It's more than 720.
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I asked TivoZA this question a while back and I remember him saying it's for closed captioning or something like that.
 
feo said:
I asked TivoZA this question a while back and I remember him saying it's for closed captioning or something like that.
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I don't think so, else Full HD panels would have more than 1080 lines.. which they don't in general.
 
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