Strange resolution problem with non-anamorphic DVDs ... help!

Discussion in 'Displays' started by Samuel_Fred, Jan 6, 2004.

  1. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    I'm new here and don't really even know if this is the right place for this question, as my troubles might originate with my DVD player (though I suspect this isn't the case).

    I recently purchased my first HDTV, a modest 30" Philips flatscreen projection HDTV (30PW850H) which is now replacing my 27" 4x3 TV.

    I am noticing some peculiar disturbances in the resolution of the picture with certain DVDs. (Note: I only use the TV to watch DVDs.) My DVD player is a Jaton PSD7611K (progressive scan, hooked up with component cords). I swear by this DVD player mainly because it can zoom in and out incrementally, which allows me to fix the TV's overscan, and even to watch non-anamorphic discs without black bars on all 4 sides.

    (An aside on overscan: why is it that all TVs do this? And why is it that no one seems to care that 16x9 TVs are not the proper dimensions for ANY film's original aspect ration?
    No film that I know of exactly fits the screen, that is, if one properly corrects overscan. 1:1.66 films, for example, still have black bars on the left and right (if overscan is fixed), and 1:1.78 (and wider) films still have "letterboxing" on top and bottom). This doesn't particularly bother me, but if the TV were a tad wider, then at least I would be using the whole screen for a large portion of the films I watch.)

    Back to my problem:
    Widescreen films look great on this TV, no complaints.
    My problem is with non-anamorphic discs, mainly with 1:1.33 (or thereabouts) films. I always adjust overscan, even on these films, which requires a little zooming out to insure I see the whole picture (top and bottom is always cropped with 1:1.33 films). But when I zoom out I see noticeable loss of resolution, the appearance of invisible lines (ok, so they don't "appear") that can break up the image, if only subtely. My wife thinks I'm nuts, but I notice the difference, and when I hook my DVD player up to my old TV this interference effect doesn't happen. It's sort of like pixellation, a series of parallel horizontal lines that become slightly visible when interfering with vertical or other lines in the picture.

    The more I toy with this, the more I think that the picture is poorer even before I zoom out, though with each level of zooming the interference becomes more noticeable.

    I'm totally confused, because I would think zooming a picture OUT (making it smaller) would, if anything, give the picture more lines of resolution. What's going on here? I also notice this effect on non-anamorphic widescreen discs, but only when I zoom OUT *which I would never do with a non-anamorphic picture). I can't really say if this happens with anamorphic discs, though I think I notice the same problem when I zoom the picture to a MUCH smaller size.

    This would lead me to believe it's the process of zooming out that is creating the problem, but I repeat that when I try it on my old (non HD) TV it doesn't happen, and the effect is unnoticeable on anamorphic discs (at least with the first few degrees of zooming).

    Has anyone had these problems or know what might be causing them, or how I might adjust my set up to fix it. Any help would be greatly appreciated.

    Thanks,
    sam
     
  2. John S

    John S Producer

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    Try some real 480p through your component video connection.

    You will get bars on the left and right sides on 4:3 material.


    Good luck with it.
     
  3. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    >Try some real 480p through your component video connection.

    I mistakenly wrote "composite" in my first post. I of course have the DVD player hooked up with the 3 colored component cords. What do you mean "real 480p"?

    >You will get bars on the left and right sides on 4:3 material.

    This I'm fully aware of and have no problems with it.
     
  4. John S

    John S Producer

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    Hmm well your already doing what it then...

    Does it behave more normal if you switch to 480i, instead of 480p from your DVD player?
     
  5. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    We have 16:9 because it is a compromise ratio ...

    There is no winning when it comes to picking the "right" aspect ratio for HDTV design.

    It is also the ratio you end up with if you place all the different ratios on top of each other and equalize each one for area ...

    The box you draw around all these ratios is ... 16:9 ...

    regards
     
  6. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    >Does it behave more normal if you switch to 480i, instead of 480p from your DVD player?

    I'm sorry, but I really don't understand the meaning of i versus p. What's the difference?

    Thanks a lot in advance.
     
  7. John S

    John S Producer

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    If your DVD player is Progressive scan, and your using component video it is out putting 480p EDTV, usually there is an option in the system menu of any given DVD player that allows your to turn this off and out put 480i, or standard definition TV.

    Some HDTV's kind of lock in full when fed 480p or above, generally there is a way to have the TV give you 480p back using the component video DVD 480i source. It is worth a try for you anyways.
     
  8. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    Thanks.
    Yes when I switch the output to interlaced (480i) this effect does not happen-- the problem is my HDTV does not like the 480i so much -- the picture quality is really poor (very dark, lack of color). I'd rather use 480p with lines of interference.

    But as a clue to what's causing the problem, with 480i output these lines disappear. The image on my old (non-HD) TV with 480i is nearly perfect. Now if I could only get this good an image (for 4:3 aspect ratio films) on my HDTV!
     
  9. John S

    John S Producer

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    Do you have a way with your particluar HDTV to have it provide Progressive scan? This is should fix you right up, I would think. I think one of the component inputs on your TV is for 480i specifically. No?

    I have a 60" Philips, I had thought your model had similar inputs as mine is all.
     
  10. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    Thanks for your help, John.
    There are two inputs for the 3 colored component cords: AV1 and AV4. I still don't know which I'm supposed to use. I've tried both. I don't see a difference. I think one is ONLY for 1080i. I now have it hooked up to AV4 and when I switch my player to the interlaced mode the picture is really bad-- many more of those lines breaking up the picture. I guess I should try the interlaced mode on AV1.

    Is there something in the TV set-up menu that needs to be switched?

    thanks again.
    Anyone else on this forum using a Jaton who might be able to chime in...?
     
  11. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    I checked: the TV displays whatever the DVD player puts out. When I switch the DVD player mode to interlaced I get 480i, when switched to progressive I get 480p. It makes no difference if the player is hooked up via AV1 or AV4. Either way 480i looks horrible, worse than the problem I'm trying to fix.

    The problem--strangely enough--seems to be with the 4:3 dimension films. The Hitchcock Collection edition of "Shadow of a Doubt," for example, shows the interference lines I described above IN THE FILM. The widescreen MENU of the DVD does not display these problems!! Weird...

    Help!
     
  12. John S

    John S Producer

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    That is strange...

    On my set the component AV1 is the one it provides the progressive scan on. 480i does not even work on the AV4 component input, it must be 480p or higher.


    Dang quirky stuff, isn't it. Life was easier with NTSC, STD, svideo and composite no doubt.
     
  13. chris*b

    chris*b Stunt Coordinator

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    I would bet that the processor in the DVD player is causing the problems, especially since you are zooming it. The player is having to process this, and it just might not be to great at it. Just a thought. I have never seen a Jaton player before.
     
  14. Samuel_Fred

    Samuel_Fred Stunt Coordinator

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    Indeed it IS the DVD player that is doing it. I tested it on another HDTV and found the same results.

    I'm still bafffled by two things:

    1) Why this only occurs with 1:1.33 films and not with anything wider.

    2) Why the 480i resolution on my HDTV is so much worse than it is on my plain old (non-HD) TV. Isn't the deinterlacing done by the DVD player?
     
  15. John S

    John S Producer

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    If the DVD player is set for Progressive scan, your de-interlacing is being done by the DVD player.

    Right now, my TV is definetly providing mine though, and it works well.

    On your old TV, I would assume you were using Svideo for the connection. HDTV's do reveal many artifacts that could not be detected in non-hdtv's for sure.
     

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