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Discussion Starter · #1 ·
I have never been able to get this question fully answered.... When you look at the specs of some RPTVs and the native resolutions they support, they usually list 480p and 1080i. Some, including Hitachis, list 540p and 1080i.


My question is: RPTVs that can display 1080i can also display 540p natively?


Thanks,


Alric
 

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The purpose of 540P versus 480P is that first of all it really isn't true 540 p but upsampling, as is the case with all internal numbers on the RPTV's, and keep that in mind. This means that is you put a DVD in with S Video, than it will upsample it to 540 and say P but it really is simulating and given the chance you should always bring it in 480P through component at a true progressive scan. The 540 allows the upsample to make analog pictures look less stretched and makes the edges more normal on the zooms in doing so. The Hitachi works very well in this regard and the Mitsubishi and it's 480 and the Elite don't do as well. You will most likely see alll of them copy Hitachi in this regard next year.


Your problem lies in thinking that when they say 540P it is really progressed, and it isn't. A good rule of thumb is if it doesn't come component, it can't truly be progressive scanned. You will actually see some of the low level people like circuit city with the XWX Hitachi 57 inch on the floor with a non progresssive scan player hooked up, but with component cables, thus a true job of a moron, as the component cable tells the TV not to line double as it is already doubled by virtue of that being hte purpose of the those cables, and yet the player used can't do it. The reason for this is you don't want to upsample from 480 to 540 as the inherant processing noise isn't worth only 60 lines.


I hope that helps and that is a good question, although if you had seen a Hitachi with that and all the TV's without it in a analog mode, you would truly appreciate what it does and it is huge.
 

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Discussion Starter · #3 ·
I know for a fact the 540p of the Hitachis is real. If fed a 540p signal (1440x540p) the internal scalers of the Hitachi are off.


The question is whether they are off in all 1080i TVs..


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Alric,


AFAIK, the 540p in the Hitachi's (and Toshiba's) is really not a good thing. Basically, it's their way of cutting costs by not having to handle multiple scan rates since 540p uses the same scanning frequency as 1080i while 480i/p uses a different one. At best, the 540p upconversion that's necessary to convert your 480i/p input will not introduce artifacts that are noticeable to you, but that will depend a lot on your own eyes. Nevertheless, it seems that most owners don't notice any upconversion artifacts w/ this year's models from both Hitachi and Toshiba, so maybe you won't either. You should see for yourself though.


_Man_
 

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Discussion Starter · #5 ·
That's the thing I don't have a 480i or 480p input. I have a true 540p input.


My question is the same, do all 1080i capable TVs can also do 540p or is it just the Hitachis and Toshibas?


Thanks,
 

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Quote:
Originally posted by Addicted Help!!
The purpose of 540P versus 480P is that first of all it really isn't true 540 p but upsampling, as is the case with all internal numbers on the RPTV's, and keep that in mind. This means that is you put a DVD in with S Video, than it will upsample it to 540 and say P but it really is simulating and given the chance you should always bring it in 480P through component at a true progressive scan. The 540 allows the upsample to make analog pictures look less stretched and makes the edges more normal on the zooms in doing so. The Hitachi works very well in this regard and the Mitsubishi and it's 480 and the Elite don't do as well. You will most likely see alll of them copy Hitachi in this regard next year.
Addicted, you've got this one wrong. The Toshiba and Hitachi do have true 540P. In fact, the only modes they have are 540P and 1080i. Every signal is converted into one of these two modes. I'm not sure what you're talking about stretches and zooms. It has nothing to do with it.


480i is doubled to 480p and then converted to 540p.

480p is just converted to 540p

540p is displayed as 540p

720p is converted to 1080i

1080i is displayed as 1080i

Quote:
AFAIK, the 540p in the Hitachi's (and Toshiba's) is really not a good thing. Basically, it's their way of cutting costs by not having to handle multiple scan rates since 540p uses the same scanning frequency as 1080i while 480i/p uses a different one.
It's always best to display in the native format, but the 540 upconversion is an acceptable trade-off. Having a single point of converence and focus is a good thing.

Quote:
My question is the same, do all 1080i capable TVs can also do 540p or is it just the Hitachis and Toshibas?
Hitachi and Toshiba like you said and also it looks like the new Pioneer Elite (x30) does the conversion to 540 this year. Most of the others will not display 540 natively.


John
 

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Quote:
Originally posted by Alric
That's the thing I don't have a 480i or 480p input. I have a true 540p input.


My question is the same, do all 1080i capable TVs can also do 540p or is it just the Hitachis and Toshibas?


Thanks,
Alric,

It is NOT just Hitachi and Toshiba (Sharp and some others also upconvert to 540P)

Although I can not definitively answer the question as to whether 1080i-capable TV's can accept 540p input...I believe the answer is NO. (at least not neccesarily)

You need to segregate the TV's accepted INPUT formats from it's stated DISPLAY formats. So the manufacturers spec will be the only way to truly tell.
 

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Discussion Starter · #8 ·
Quote:
It is NOT just Hitachi and Toshiba (Sharp and some others also upconvert to 540P)
That is what confuses most people. The 540p of Hitachis and Toshibas is not the result of upconvert. If fed a true 540p signal they will display it natively without upconverting.
 

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There are other reasons why 540p.


Hitachi engineers thier CRT and lense systems for HDTV. 540P more closely resembles the resolution of HDTV.


With 480P displayed on a CRT and lense system optimized for 1080i, there is problem of scan lines and the width of them...


480P optimized CRT and lenses requires lines that are too fat for proper display of HDTV...
http://www.hitachi.com/tv/discover/t...d_proj06.shtml


Click the link and watch the first apple quicktime video....
 

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Quote:
Originally posted by Alric
That is what confuses most people. The 540p of Hitachis and Toshibas is not the result of upconvert. If fed a true 540p signal they will display it natively without upconverting.
But where would you get a 540p signal? That's not a standard format for anything. The earlier explanation of why 540p exists on so many sets (conversion of 480i/p to format that uses same scan rate as 1080i) is correct.
 

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Discussion Starter · #11 ·
Quote:
But where would you get a 540p signal? That's not a standard format for anything. The earlier explanation of why 540p exists on so many sets (conversion of 480i/p to format that uses same scan rate as 1080i) is correct.
DVDs looks stunning at 960x540p or 1440x540p using a computer to drive a Hitachi widescreen.


Cheers,
 

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Quote:
Originally posted by Alric
DVDs looks stunning at 960x540p or 1440x540p using a computer to drive a Hitachi widescreen.


Cheers,
They are also stunning with VirtualHD when fed a simple 480i signal...


-the differnece between Sony, toshiba ect... and hitachi.


hitachi upconverts dvd's from 720x480 to 1080iX1280 or 540px1280.


Sony does 960ix720 or 480px720...


optimized for 480p, the sets look sharper on 1080i at first, and un calibrated because of the thickness or not of the scan lines....


Kinda like the sharpness control....cranking it one way reduces or thickens the scan lines on a tv.....


But, the gaps between scan line becomes apparent on a calibtrated set...


It's why sharpness is better left on the lower side. (try AVIA)


To most people who do not know better, cranking the sharpness seems like a sharper picture....but really it is not...and is lowering the picture quality by reduceing the thickness of the scan lines and makeing them more apparent.


Click the link above I posted....
 

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Discussion Starter · #13 ·
Quote:
They are also stunning with VirtualHD when fed a simple 480i signal...
Mfusick,


The image quality of 540p native on the Hitachi is so much better than using the virtual HD that for me 480i is unwatchable... :)


Cheers,
 

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Quote:
To most people who do not know better, cranking the sharpness seems like a sharper picture....but really it is not...and is lowering the picture quality by reduceing the thickness of the scan lines and makeing them more apparent.
Sharpness control setting should not affect the thickness of scan lines. I don't even see how it could, frankly. Sharpness controls are peaking circuits that affect the luminance signal's high-frequency response. The effect is thus on the horizontal, not the vertical. Nothing in the video signal modulates the width of a scan line.
 

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Aaaah! Now Alric's question makes sense to me. Maybe next time, you might want to clarify that you intend to use an HTPC to drive the TV. :D


Anyhoo, theoretically, ANY upconversion from 480i/p to 540p can ONLY be worse, not better, although it may not be noticeably worse. However, how things really look in the end results will vary simply because there are other factors that come into play, eg. the benefits of optimizing for one scanning frequency MIGHT potentially be enough to offset the loss of accuracy from upconversion.


Anyway, none of this answers the original question. But I suspect you'll have to hunt down the answer for each specific brand of TV, if not specific model. My guess would be that any TV that doesn't do the 540p upconversion won't be able to handle a 540p signal simply because they are not designed for it.


BUT really, why do you even care if a TV supports 540p natively unless the TV would otherwise force upconversion?? Even though your HTPC can do a superb job of upconversion to 540p, that doesn't mean it'll be better than simply feeding a 480p signal into a TV that doesn't do 540p.


BTW, I would take the Hitachi link w/ a grain of salt. Afterall, why wouldn't they paint the best possible picture about their adoption of 540p upconversion when they are one of the first makers to do that and can benefit by cutting costs?


Anyhoo... Just my $.02.


_Man_
 

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Quote:
Originally posted by MDRiggs
Sharpness control setting should not affect the thickness of scan lines. I don't even see how it could, frankly. Sharpness controls are peaking circuits that affect the luminance signal's high-frequency response. The effect is thus on the horizontal, not the vertical. Nothing in the video signal modulates the width of a scan line.
Do you have any analog TV's in the house?


Crank the sharpness and watch the scan lines.... they become much more apparent.


The width of the actual lines decreases, while the space between them increases.


This is not as noticable on HDTV's...but instead becomes grainy quickly.
 

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Believe some have indicated that there's no such thing as true 540p or 540 native. If you use a PC to convert 480 to 540p then you've simply upscaled the scan rate and probably the horizontal resolution. My vintage Philips RPTV was designed for 480p and 1080i, and only sideconverts 720p to 1080i. But like other 1080i sets it could handle a 540p input from a PC because the two signals are so similar electrically.


A related 540p/1080i issue is that when motion is involved in a true HDTV 1080i scene, the image tends to look very similar to the same scene at 540p. That's because actual vertical resolution with interlaced 1080i HDTV drops so sharply, as outlined by the ATSC test committee here and in a simplified form here . -- John
 

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Discussion Starter · #18 ·
Quote:
If you use a PC to convert 480 to 540p then you've simply upscaled the scan rate and probably the horizontal resolution.
"Simply" in an understatement here. Computer graphic cards are comparable if not better than Faroudja based scalers. Much better than the scaling done internally by most RPTVs.


If you hop on to the Home Theater Computer forums you will find comparisons between very expensive scalers and HTPCs, and HTPCs are found to be as good if not better than very high end scalers.


I find the Hitachi at 540p native fed by an HTPC to blow away the image quality of any Sony (480p) RPTV fed by a high end (Panasonic RP-91) progressive scan DVD player.


Cheers,
 

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I totally agree with Man-Fai Wong.


Also, if you have to use a HTPC to get the best DVD picture from the Hitachi then in my opinion it's counter-productive. To me it's just too much hassle to use a HTPC for a RPTV, if you are set on using a HTPC then start looking at FP instead.


FWIW I actually returned a Hitachi RPTV precisely because of the 540p upconvert. There is not enough difference between a RPTV that does native 480p and one that is driven by HTPC at 540p to justify the extra effort and expense IMHO.
 

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I have to agree with Alric. DVD image quality via HTPC blows away 480i/480p on my Hitachi 51SWX20B. It's well worth the effort in my opinion. I was starting to think I was the only one that noticed the upconversion artifacts on these sets (not just Hitachi).


HTPC can have other uses as well. It can drive a card like MyHD for receiving and recording High-Def broadcasts. You can use software like DScaler for a non-linear stretch that's better than Hitachi's 4:3 expand. You can playback archived video using Divx or WM9 with decent quality. The list goes on.
 
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