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Panasonic 36 WS Acuity pic issues

Discussion in 'Televisions' started by darklight, Oct 8, 2004.

  1. darklight

    darklight
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    Have recently purchased a 36" widescreen Panasonic Acuity. THis is running with a Panasonic RV41 multi region DVD player. The problem I seem to have is that at the point the black widescreen ends( watching 2:35:1 ratio) and the picture begins a sort of ghost line is seen from one side of the frame to the other, top and bottom. The screen is set on 16:9 as is the DVD out[put but it's still there if I change to the other screen settings on the TV.
    It's hard to explain exactly the nature of the line as you still have about 1mm of picture before the balck begins which seems slightly lighter in tone than the rest of the picture. Does anyone have any idea what that might be as I had a look in Currys and some of the other widescreen TVs also seem to have it.
    By the way the DVD is connected to the TV from S-VHS to Scart on AV4. I've tried hooking it with scart to scart but the line is still present.
    Since the TV is componsite compatable with a progressive scan DVD player I was thinking of purchasing the Yamaha 520. Would this help.
    Any ideas or responese would be greatly appreacited.
    Many thanks.
     
  2. red16v

    red16v
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    I can't speak for your particular model but in principle what you're describing sounds typical of electronic (artificial) picture sharpening. There are lots of variation on a theme but the general principle is that the circuitry is looking for dark to light (and vice versa) transitions and it then decides that this is an 'edge' and tries to sharpen it. It achieves this (in very general terms) by making the darker part darker and the lighter part a bit lighter. You can imagine then that a black to white transition (as you are describing) would be seen by the circuitry not only as a transition but a large one and accordingly is likely to apply maximum sharpening. The correction signal that's added to the original video signal usually takes the form of a small 'sine-wave' (I'm being very general here) and so the effect graduates over the edge - hence most likely why the first (and last?) line of picture appears lighter or greyer. I hope this makes some sense. A lot of tellys do this and as the same principles are used in some equipment the broadcasters use to sharpen pictures at the point of origination sometimes its 'incoming' to you !! Perhaps you may find adjusting the sharpness settings on your tv may reduce the effect you're seeing, but remember of course the entire picture will be affected. regards, yt.
     
  3. Tight Git

    Tight Git
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    Red16V,

    Forgive me, but the artificial sharpening that you describe is surely only relevant to horizontal transitions (ie vertical lines).

    If I understand Darklight's description correctly, he is referring to the horizontal lines above and below the 2.35 ratio image.

    Of course, I may be wrong...
     
  4. red16v

    red16v
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    Hi Tight Git (I'm sure you're not really tight!) The technique I've described can be applied to horizontal and vertical correction. There are a number of ways of doing it, my description is just one. It might be that Darklights 'effect' is due to something completely different, my suggestion is only one. What led me to think it might be picture sharpening is that however it's carried out a black to white (or white to black) is the most extreme transistion you're going to get and maximum sharpening would be applied 'over' the transition - I've seen the effect described by Darklight for many many years, usually the source was film. regards, yt.
     
  5. Tight Git

    Tight Git
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    (Oh yes I am! :laugh: )

    That's fair enough. I was thinking of the Velocity Modulation system introduced by Sony many years ago. I know the Acuity system produces 833 lines from 625, but thought that only interpolation was involved. Does it digitally sharpen the vertical definition as well?

    Darklight,

    Sorry, I should have said welcome to the Forum. :thumbsup:
     
  6. darklight

    darklight
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    Thanks for the welcome and very fast reply on what may be my problem.
    Just today I tried various DVD's PAL and NTSC and another DVD player and they all seem to have these lines. One thing I did notice which seems interesting is when I tried a PAL DVD with a 2:35:1 ratio but not anamorphic the lines did not seem to be present. Now I can't be sure the DVD is definatly not anamorphic, it just didn't mention it on the case where most do ( the PAL DVD is A Perfect World, by the way). All the other DVDs even PAL that did state anamorphic carried the lines( such as NTSC Start Wars Trilogy, LOTR's, The Alamo and PAL The Big Blue , Solaris).
    Anyway it may have nothing to do with it at all. What do any of you think?

    PS. I even think the lines are noticable on a 1:85:1 ratio. Obviously the screen is filled but you can just see the lines at the screen edges...

    May be I'm going mad... :D
     
  7. darklight

    darklight
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    One thing I forgot to mention is that this effect does not seem to be present when I'm watching SKY movies that are in 2:35:1. ratio.
    Would a Progressive Scan DVD player produce a picture without these lines?
     
  8. red16v

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    TightGit - regretably I can only make broad comments. I'm not familiar with Sony domestic products.

    Darklight. I'm not familair with DVD players etc, I've only just bought one and haven't even played a DVD on it yet - we don't tend to watch much Telly at all !! I hope someone with more direct knowledge of these combinations may be able to offer you more helpful advice. regards, yt.
     

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