Progressive Scan Problems

Discussion in 'Beginners, General Questions' started by ericEsquire, Aug 31, 2004.

  1. ericEsquire

    ericEsquire Extra

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    A couple days ago I picked up a 51" Magnavox Widescreen HDTV. I also have a Toshiba progressive scan DVD player. I was able to get it hooked up through the HD AV-4 inputs, but I'm having some issues...

    When I'm playing Lord of the Rings: The Two Towers - the screen is gorgeous - exactly as I had hoped.

    When I'm playing The Girl Next Door (Brand new movie) - it's horrible - I can see some sort of scan lines during times of high movement (this can include something as simple as walking across the school campus).

    When I'm playing Indepdnance Day - Everything seems fine

    When I'm playing The Matrix (a DVD I figured should have what it takes) - I see the same sort dark/black scan lines.

    -------------------------

    My question is, are all DVD's created equal? Do they have to be special DVD's to work with progressive scan/display properly?

    Is this a problem that many encounter, and hopefully fix?

    I'd love any suggestions, I hate not being able to enjoy my new TV the way it should be.

    Thanks for all of your help!
     
  2. Jack Briggs

    Jack Briggs Executive Producer

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    Eric, not all DVDs are created equal.

    And even with progressive scanning, you still have scan lines -- nature of the CRT beast. But in 480p, with all lines refreshed simultaneously, the picture structure is smoother and less noticeable than with interlaced scanning.

    Now, on a big RPTV, you're paying really close attention to video artifacting that may have escaped your notice on a smaller direct-view set.
     
  3. Michael Reuben

    Michael Reuben Studio Mogul

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    Also, not all progressive scan players are created equal. I'm not familiar with the Toshibas, but if you list the model, someone might be able to tell you about it.

    Have you calibrated the TV? Scan lines will be more obvious if the contrast is cranked too high, which is how TVs are typically shipped from the factory. You might want to look at the calibration sections of our FAQ (link in my signature).

    M.
     
  4. ericEsquire

    ericEsquire Extra

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    Shouldn't progressive scan show less of the scan lines than when in regular mode? When I have the DVD player plugged into just a composite video input (is that correct?) and i have progressive scan turned off, it plays fine with no flaws - other than the fact it's about half the quality as when progressive scan is on (besides the scan lines).

    The Toshiba DVD player is an SD3950 and the TV is a Magnavox 51MP392H - pretty entry level stuff but I've read some great reviews on both of them so I was hoping to play ball with it.
     
  5. Allan Jayne

    Allan Jayne Cinematographer

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    Since you said that the composite connection plays fine, this suggests that the player's de-interlacer is deficient. All players have an MPEG decoder that delivers interlaced video, the progressive players have a de-interlacer as a second stage to make progressive scan.

    Most of the quality loss you saw using composite is from the composite format, not the fact it is interlaced. The TV is still putting progressive scan on the screen, the TV uses its own de-interlacer for incoming interlaced video instead of gearing down the picture tube scanning. The TV's de-interlacer may or may not be better than the player's.

    Video hints:
    http://members.aol.com/ajaynejr/viddoubl.htm
     
  6. ericEsquire

    ericEsquire Extra

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    Well I have the DVD player hooked up to the component inputs now (which I am under the impression is a step up from S-Video) and I don't get any problems on screen. It's only when in progressive scan mode hooked up to the HD Component inputs.

    The guy at Magnolia Hi-Fi told me that it's probably cables and wanted to sell me some $140 2M component video cable set, so I found some comparable ones at a different store for $40 and picked those up - but no difference whatsoever, not even a little bit.

    The movie that has the most problems doesn't have much motion either, it's just people walking across a high school campus and it gets a little jittered.
     
  7. ericEsquire

    ericEsquire Extra

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    By the way - thanks for all the help - this site has such a wealth of information, I really appreciate it!
     
  8. Michael Reuben

    Michael Reuben Studio Mogul

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    Is the player's progressive mode on or off in this setup?

    M.
     
  9. ericEsquire

    ericEsquire Extra

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    When hooked up to the regular component inputs i have it turned off, otherwise it just doesn't display.

    Just a note: I was reading about the Chroma Bug - the description of what's happening sounds similar to what I'm seeing - however the lines go across the entire screen.

    For instance - if there's a bright outdoor background and a guy with dark hair walks across the screen, you can see the dark lines across the entire screen equal to the size of his head/hair. Does this sound like Chroma Bug?
     
  10. John S

    John S Producer

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    Does the HDTV provide Progressive scan? There have been cases where progressive scan from a DVD player, can sort of conflict with the TV's own internal line doubler. If so, even if you feed it 480i via component video, this may be the proper solution. I do see it has no 3:2 pulldown in it's specs, sort of a drag for sure, if this is what is going on.
     
  11. ericEsquire

    ericEsquire Extra

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    3:2 pulldown - I was reading something about that yesterday - that's something that the TV should have or the DVD player? Are there external processors that can do this type of thing if need be?

    Do you think that this feature not being available is whats causing this?

    In the owners manual it tells you how to hook up a DVD player with progressive scan capabilities - so I assume the TV has it.

    I'm a bit more familiar with studio recording equipment where you can have a lot of different effects processors, etc. - that are external from you computer, for instance. Are there similar boxes for home theater?

    Thanks for dealing with the newbie so well [​IMG]
     
  12. John S

    John S Producer

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    Actually your TV can have it, your DVD Player can have it, or both.

    The 3:2 pull down is done when the video is made into progressive scan. 3:2 pull down is supposed to identify film ques, and take care of the fact that Video and film run at different frame rates.

    There are a few TV's that if you send them progressive scan, the internal progressive scan still attempts to be done, and there is a conflict of sorts with it.

    On those sets, you simple provide them 480i on the component input and let the TV provide the progressive scan.

    The other can be to get one of the newer DVD players that allow you to scale the DVd output all the way to 1080i. Most CRT RPTV's will not touch this signal at all, and pass it right on through. Now properly, your TV is supposed to idientify 480i -vs- 480p and only try to provide the progressive scan on 480i input, but as I said, there have bee a few sets, that do not do this properly, and people generally just send them the 480i via component video from their DVD, and let the TV provide the progressive scan.

    I don't know if yours is one of those sets of not, to tell you the truth. I just find your particular issue interesting to say the least.
     
  13. Allan Jayne

    Allan Jayne Cinematographer

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    >>> For instance - if there's a bright outdoor background and a guy with dark hair walks across the screen, you can see the dark lines across the entire screen equal to the size of his head/hair. Does this sound like Chroma Bug?

    This is not the chroma bug but is often seen as a result of problems with the TV's picture tube circuits (black level retention) which come well after de-interlacing and/or scaling. But in your case, since you do not see it with composite or S-video or interlaced-component input, the problem has to be elsewhere. It is possible for a de-interlacer to cause it but the de-interlacer would have to be mighty p*ss-poor to have a problem that bad.

    When DVD is played at 1080i, three operations take place:
    1. DVD data is MPEG decoded to 480i
    2. 480i is de-interlaced to 480p
    3. 480p is scaled to 540p
    Both 540p and 1080i go onto the picture tube the same way, as 1080i.

    A DVD player may do all three of these operations.
    The usual progressive DVD player in progressive mode does 1 and 2 and an HDTV does just 3 in that case.
    A progressive DVD player in interlaced mode or a regular player does 1 and the HDTV then does 2 and 3.
    Yes there do exist external processors that do just 2 and external processors that do 2 and 3.

    If the source is 24 fps film, the 3-2 pulldown is created during stage 1. Stage 2 may or may not look for the 3-2 pulldown (better de-interlacers do look) to assist in getting matched odd and even fields to create the progressive scan frames, but as soon as if/when this is done, the 3-2 pulldown is retained or recreated before going on to stage 3. Very simple de-interlacers that do not look for 3-2 pulldown often deliver results with moving subjects having feathering extending a little way to each side, suggestive of coarse visible scan lines.

    We cannot rule out an idiosyncrasy between your DVD player's stage 2 and your TV's stage 3.
     
  14. ericEsquire

    ericEsquire Extra

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    Well my original DVD player, some cheapo thing from Best Buy that came with cheapo surround sound (back when I had a POS TV and didn't really care much - it was $80 for the entire setup 5.1 sound and dvd player) has progressive scan and I didn't know that. It doesn't say it anywhere on the box.

    I had taken it to my fathers and traded him for his Toshiba which was progressive scan because he doesn't have an HDTV and can't take advantage of it anyway.

    Well I got my old one back since the Toshiba wasn't working, and for shits and giggles i plugged the component video into the HD input on the TV and then hit the PAL/NTSC button on the remote a few times - the screen flickered a bit, then a bright, crisp, perfect picture appeared and said (480p) on the TV.

    I checked it with all of my DVD's and it works flawless. I can't believe that this inexpensive DVD player is running circles around the Toshiba - who'd a thought?

    Hopefully this keeps up!
     
  15. Jeff Gatie

    Jeff Gatie Lead Actor

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    Yes, I've heard the 3950 can be a less than stellar example of progressive scan players, sort of like the early inexpensive Pioneer player (forget the model). I think the 3950 is a relatively older model, much improvements since then.
     
  16. Allan Jayne

    Allan Jayne Cinematographer

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    An ordinary el-cheapo interlaced DVD player going into a recent vintage HDTV can give extemely good results with the TV doing the de-interlacing.

    The main difference between cheap MPEG decoding and top of the line MPEG decoding is processing power, lots of fast motion may cause the cheap decoder not to keep up and coarse checkerboarding pixellation to appear.
     
  17. ericEsquire

    ericEsquire Extra

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    Explain "recent vintage" - sounds like an oxymoron to me...
     
  18. Jeff Gatie

    Jeff Gatie Lead Actor

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    .

    No a vintage is just the year of the grape harvest that a wine is fermented from. You can have recent vintage, old vintage, late vintage, early vintage, etc. Essentially, "recent vintage" means made recently.

    Now back to our regularly scheduled program.
     
  19. ericEsquire

    ericEsquire Extra

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    My apologies - I'm not as think as you drunk I am Ocifer.
     
  20. Rocky F

    Rocky F Second Unit

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    I was just looking at this TV set myself, seems a great price for a first HDTV, but I was concerned about the 3:2 pulldown thing myself. I understand that this is to correct film's 24fps to video's 30fps, but I really don't understand how it works. I mean films on video and DVD have never had a problem on old analog sets. Anyway, my question is, how much would I notice the lack of 3:2 pulldown, and should I just first try my 3 1/2 year old interlaced DVD player before I go out and buy a progressive player?
    Also, I've seen size listings for this set at 3 different places and they are all different. Do you know it's correct size and especially how deep the top of the set is?

    Sorry for hijacking the thread, I did a search for the model and this is what I got.
    Thank for any input.
     

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