Digital Video Noise Reduction = evil laserdisc feature?

Discussion in 'Archived Threads 2001-2004' started by Michael St. Clair, Jul 29, 2002.

  1. Michael St. Clair

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    I don't have one of the really high-end players, but I have a CLD-D703 (704 without AC3) and an LX900. Personally, I think the Panasonic has the best picture quality of the two, but it's really, really close. Pioneers are easier to get serviced it seems.

    I used to think DVNR was useful. The LX900 just has off/high/low settings, but the D703 has the five adjustable chroma settings and the five adjustable luma settings. I used to use these with 27" and 32" TVs and the noise reduction seemed useful. For going on a year now, I've been using them with a 53" HDTV.

    On the bigger screen, I can't stand the noise reduction. To me, it seems to always reduce detail. I'd rather have the noise and keep the detail.

    Is it just me? Or is it my players?
     
  2. Lyle_JP

    Lyle_JP Screenwriter

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    It's not just you. I replaced my DVL-909 with a used CLD-59 for the very reason that the 909 has DVNR that cannot be turned off, and on my 65" Mitsubishi, the DVNR artifacts looked horrible. It's not just the loss of detail, but the smearing and trailing effects as well (especially if what you're watching has a good deal of fog, smoke, or other gradients in the picture).
    -Lyle J.P.
     
  3. Michael St. Clair

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    Lyle,

    Well, it is nice to hear someone agree with me. So much was made of the noise reduction features of higher-end LD players towards the end of the LD life cycle.

    With a smaller, interlaced display, I thought noise reduction was pretty sweet for certain noisy discs. The larger displays reveal a multitude of sins. I now fear any digital noise reduction for laserdisc.

    Anyone else have some observations?
     
  4. Philip Hamm

    Philip Hamm Lead Actor

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    The DVNR on LD definitely causes artifacts. I like that it can be defeated on my players.

    This is a big reason that I bought my CLD-99. Louis Carliner explained it to me when he calibrated my set a few years ago.

    In order for niose reduction to work on both Chroma and Lunimance, the signal has to be split through a comb filter. On a anything less than a CLD-99, that comb filter is only a very good 2-D filter. So the signal is split to chroma and luminance then you have the DVNR, then if you are using the composite output the "cleaner" signal is recombined. If you have a modern TV, then most likely it is doing some advance 3-D filtering on the composite in, and perhaps line doubling and more noise reduction.

    So what you end up with is a hell of a lot of processing, with the weakest link being the LD player's noise reduction on the 2D filtered luminance and chroma signals.

    The CLD-99 performs VDNR on the chroma and liminance signals after they have been separated with a top notch (even by today's standards) 3-D comb filter. You use the S-Video plug to go to your TV and all youv'e got is line doubling (if that - my old NTSC does not need it). If you've read this far, you can probably imagine that the DVNR probably works far better on the CLD-99 than lesser players. Assuming you use the S-video out of course, otherwise you've got more conversion in the TV happening.

    Anyway, it can be defeated on most players, but it does cause artifacts, including banding which is very noticable on concert videos not unlike DVD.
     
  5. Michael St. Clair

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    Philip,
    Multiple sources on Usenet studied the schematics in the service manuals for the CLD-D704, CLD-79, CLD-97, and CLD-99. These 4 players (plus various clones and the D703) do not use the comb filter before the noise reduction IC. The noise reduction IC takes composite in and puts composite out, then feeds both the comb filters and the composite output of the player.
    Now, what the noise reduction IC does inside itself to process Y and C noise reduction separately is anybody's guess (other than who designed the guts of the silicon), but the much touted comb filters of these players are outside of this process, and bypassed for composite output. FYI, the 97 does not allow independent adjustment of Y and C in the player, but the service manual indicates that the IC is capable of it.
    Therefore, anybody with one of these players can take the composite out and feed it into the adaptive 3D comb filter of their HDTV or Panasonic DVD recorder and know that they getting the cleanest filtered signal possible for that player. But what we don't know is if the noise reduction ICs are doing additional, lesser quality separation, and if NR is disabled, do these ICs not do the separation (one would hope so).
    Well, that's what I think, anyway. I could be wrong. Maybe Kurtis could add something here. [​IMG]
     
  6. Philip Hamm

    Philip Hamm Lead Actor

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    Hmmm... Louis Carliner gave me bad information? That's surprising. However, I can imagine that having the DVNR work on the composite signal would be easier to accomplish.
     
  7. Michael St. Clair

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    More interesting stuff from usenet. I think this is from Thad:

     
  8. Rachael B

    Rachael B Producer

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    Michael, I've always left DVNR off. I never even thought it helped really crappy mid-80's discs. Having owned the 703 & 79, their S-output won't equal the 99's. I think the 3-line comb in the 900 comes a little closer. Best wishes!
     
  9. Michael St. Clair

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  10. greg_t

    greg_t Screenwriter

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    Does anyone know how the 3D Y/C comb filter in the new Pioneer Elite and non-elite TV's compare to the one in the CLD 99? You would tend to think that it's better, being 5 years or so newer.
     
  11. Michael St. Clair

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