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DVI Vs.SDI WHAT IF ANY ARE THE DIFFERENCES

Discussion in 'Blu-ray & DVD Players & Recorders' started by alwyn, Mar 9, 2005.

  1. alwyn

    alwyn
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    Would someone kindly enlighten me on the merits of one over the other.I ask this because I see dvd players being upgraded to SDI when they have DVI to start with.
    Many thanks
     
  2. NPM108

    NPM108
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    Am no expert on this issue and was curious myself. As best I understand it with SDI you take the raw MPEG signal out of the player and are able to pass it through a scaler like the Lumagen scaler.

    I quote from Convergent-AV's website:

    SDI modified DVD players take the digital picture information direct off the player immediately after the MPEG decoder chip. This information is then serialised and sent out of the player down a single 75 Ohm co-ax cable to a suitably equipped display device or video processor.
    The advantage of this signal is that the video goes through less digital to analogue and analogue to digital conversions. This results in more detailed image with less artefacts. Below are some simplified flow diagrams:

    Hope this helps, its not a cheap route!
     
  3. alwyn

    alwyn
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    Thanks for that info,but dosent the DVI do just the same?
     
  4. KraGorn

    KraGorn
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    The problem is that there are very few players capable of outputting normal SD resolution interlaced via a digital output, most force progressive on digital because the DVI/HDMI specs. don't specifically mention interlaced output.

    Players like the Arcam DV79 and Pioneer 868 CAN output 480i/576i via HDMI and so in that case there is very little difference in the quality produced by, say, a Lumagen whether fed SDI or HDMI/DVI .. while the signal will be protected with HDCP that doesn't of course affect image quality. Denons are among the many that can't.

    The one remaining difference is that SDI outputs in the 4:2:2 colour-space of the native MPEG stream, the 868 converts this to 4:4:4 while the Arcam can be configured to keep it in 4:2:2 .. however AIUI the difference is minimal and probably undetectable to the vast majority of viewers.
     
  5. alwyn

    alwyn
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    KRAGORN,
    Thank you for that very informative info.I wonder could you advise me on the unit that I am using,it is the Teac Esoteric UX-1
    Many thanks
     
  6. KraGorn

    KraGorn
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    'Fraid I don't know that model. I have read on AVS that some Teac models can output interlaced via DVI but don't know which.

    Does your manual list output resolutions it supports? The spec shows it's progressive so I presume it'll output 480p/576p, can you disable the progressive scan on the DVI output to get 480i/576i?

    If no-one posts a postive reply one way or the other you may want to post the question in the 'Video Processing' forum where scalers are discussed, one of the guys who sell and install A/V equipment, Joe and Gordon spring to mind ), may know the answer.
     
  7. alwyn

    alwyn
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    KRAGORN,
    Yes my player supports both and the progressive can be disabled via menue.
     
  8. KraGorn

    KraGorn
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    If you're able to select 480i/576i for outputting via DVI then you'll get nigh on the same quality as if it had been modded when coonecting to a scaler or other device that can accept interlaced via DVI, such as a Lumagen.
     

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