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1024x1024 plasma

Discussion in 'Plasma TVs' started by laser, Apr 1, 2005.

  1. laser

    laser
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    I have a Hitachi 42PMA400E plasma with a 1024x1024 resolution which seems pretty unusual in the world of plasma. Most displays tend to be 1024 x768. Can anyone please explain if there are any advantages or disadantages of a display with this rsolution when viewing either standard definition or hi-def material.
     
  2. johndon

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    One thing the ALIS panel in the Hitachi does is to chop the top and bottom off a 1080i signal rather than scaling it to fit the 1024 pixels.

    For normal, standard def viewing the number of pixels doesn't make much of a difference.

    Getting a 1:1 pixel match with a PC is somewhat more problematic though...

    John
     
  3. hornydragon

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    have a search for ALIS one unfortunate issue i am 90% sure on is it will downscale 720p>512p and then duplicate a field giving you 512 x2 res................
     
  4. Liam @ Prog AV

    Liam @ Prog AV
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    The 1024x1024 models use ALIS technology to achieve this resolution. It has 1024 lines (each 1024 pixels wide) but is only able to light eery other line at once (so only 512 remian lit at any one time). It splits an image into it's odd and even line information (image is usually in this format anyway from Sky or non progressive scan DVD) and displays all the odd then all the even lines. The eye percieves this as one picture.

    The advantage is that (for similar price to low res panels) there is a bigger pixel count available to the screen to push forward more detail in the picture. The disadvantage of this technology is that as the lines are always flickered, it's never really a precisely sharp edge to that detail. It was really intended for commerical use, in the boardroom/reception etc, where it is cheaper running than other plasmas, higher resolution, but perhaps not the best for video usage in the home.

    A 1024x768 display while apparently giving less resolution, will light all pixels simultaneously for a sharper image with quite a significant amount of detail as is. And as has been highlighted above, the technology doesn't involve lopping off parts of a video signal!!

    TBH if it looks good to you, then that's job done however it does it.
     
  5. laser

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    Thanks for the explanation.
     
  6. JH4

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    Thought I'd chip in here. I have had the 42PMA400E for about 2 years now, and have run HI DEF D-VHS signals into it. The result - marvelous. A much superior picture. I've not noticed any loss of picture at the edges, and its rock solid, with no flickering.
     
  7. Stephen Wilde

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    I have a Hitachi 4121 Alis screen and it is much less sharp than my non Alis Fujitsu.
    It may perform well with a good video source but it is weak on text to the extent that I run an old crt next to it for text based uses.
     
  8. NicolasB

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    Did we ever clear up the question of what happens when an ALIS screen is fed a 576p signal?
     
  9. laser

    laser
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    I'm just hoping HD-DVD and BD will allow hi-def signals to be output through component connections to I don't need to replace the 42PMA400E.
     
  10. laser

    laser
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    Is this something to do with panel being interlaced and not liking a progressive input????

    Incidently I do have a recurring problem when I feed a SD progressive scan video singal into the 42PMA400E from by Pioneer DV-686i. Occassionally when a scene changes from a very bright to a dark scene or vica versa the picture on the plasma rolls for one frame. You can even recreate the rolling stepping forward one frame at a time. It only ever occurs between frames of very dark and bright colours and seems more prone to occur with PAL material!!! Switching off progressive scan stops the problem.

    I've not been able to find the root cause i.e. DVD player, plasma screen or DVD material as I don't have any other displays with component inputs to check with.

    Perhaps this could be a side effect of the ALIS planel or a problem with the Pioneer DVD player???

    However, switching between progressive and interlaced on the DV-686 seems to produce no benefit in picture quality anyway. I've looked at the pcture on the 42PMA400E with fast and slow moving scenes and have switched progressive scan on and off but can't actually see any difference in picture resolution, stability or flicker. Is this again due to the ALIS panel.
     
  11. Nick_UK

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    Your customers may swallow that, but I do not ! "Flickering pixels" indeed !

    I do wish that people who go on about Alis panels would read up on what they are talking about. The eyes cannot differentiate between a pixel which is switched on a 50/50 duty cycle, and one which is permanently lit, due to "persistance of vision". You also forgot to mention the advantages of Alis panels, which need fewer "wires" to each pixel, thus reducing the black spaces between pixels, resulting in a more defined and brighter picture. Also, because the pixels are off 50% of the time, screen life is extended.

    It's all on the Fujitsu (inventor of the Alis panel) web site :)
     
  12. Stephen Wilde

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    But there is a less sharp edge to text on an Alis panel for whatever reason.
     
  13. hornydragon

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    ALIS was designed for digital signage early on in PDP development when info boards and graphic displays were the order of the day for the PDP major uses, the biggest advantages of ALIS resistance to burn (comparitavely) and high brightness levels are ideal for these applications they have since been adapted for domestic use and have been reasonably sucessful but with 1024x768 panels readily avaiable and the plummeting price of SD (852 x 480) panels there is very little reason to buy ALis for domestic use, there are some applications where it is ideal and some people prefer the "look" but on the whole there is better out there..
     
  14. MAW

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    Yeah, of course Fujitsu will tell you all about the drawbacks too. Just like Panasonic advertise the green speckles in the black parts of a picture, and Pioneer tell you about mosquito noise on RGB scart of course. I'm not sigling out ALIS as you see, it's just that for 95% of professionally installed setups the cons outweigh the pros. Hitachi are to be commended for making an affordable plug and play TV out of the technology, but as a video display it has less merit than more conventional panels.
     
  15. welsh113

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    I have to agree as an owner of the hitachi i can say that it suits my needs perfectly (childrens telly and for xbox). The ALIS was sold to me as something it wasnt but you live and learn. If i was in the market right now i would be looking for something else probably the panny route but maybe an LG........
     
  16. MAW

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    LG? And why not, if you've seen it and like it. The advice that really is given out here, ad nauseum, is go see them, don't buy just cos Madasahat or Ross thinks you yould buy their screen. Fact is a lot of people do, partly because they don't get to see any others, apart from the FDE Pioneer, set up badly and way too expensive. Then there's no contest, naturally.
     
  17. NicolasB

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    Well, sort of. It was suggested a while back that a 576p signal has to be downscaled to 512p as the first of the process of converting it to 1024i (which is what is actually displayed on an ALIS panel). I think this probably does happen to a 720p signal, although I'm not sure.
     

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