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HDMI question

Discussion in 'Plasma TVs Forum' started by Jules Tohpipi, Mar 8, 2004.

  1. Jules Tohpipi

    Jules Tohpipi
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    Having just bankrupted myself buying a Pioneer 434 plasma, I’m now looking at buying a new DVD player – hopefully without having to spend a penny more than I have to (!)

    So…. regarding HDMI… and how it works…

    Take, for instance, a DVD player with a HDMI output. What comes out of its HDMI connector ? Is it literally just the raw 1s and 0s as read directly off the disc ? Or, is there some processing (in the digital domain) done on the signal before it leaves the DVD player ?

    You can probably see where I’m heading with this. If a HDMI equipped player is just passing out the raw 1s and 0s (unaltered, as found on the disc), then are we saying that the quality of the picture from such machines, is purely derived from the quality of its transport mechanism ?

    So, if this is true, then one could arguably use a cheaper DVD player (equipped with HDMI – when they become available), because it's futile paying for expensive video decoding circuitry that will ultimately be bypassed anyway. I note a great review this month (What Hi-Fi) for the new Samsung DVD-HD935 with DVI out, and scaling up to 720p, all for £150. Surely an indication of future direction on this matter.

    As a final caveat, yes I realise that transport mechs vary in quality (an entirely separate discussion), but will assume for now that the variance is marginally - not massively - significant.

    Opinions anyone ???
     
  2. Deron

    Deron
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    I knew there was something that had caught my eye...

    I know he has a new Hitachi 500e (I think). I presume that you are talking about the same item...

    Galaxy are you about. Can you let us have more info...(and pics too please)
     
  3. KraGorn

    KraGorn
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    The advatange of DVI/HDMI is that the data stream stays digital right through to the display device .. however, all processing like de-interlacing and scaling is still done (if you select it) in the DVD player, the only intrinsic difference is that it doesn't go through a DA->AD cycle like the signals present on, say, the component outputs do.

    So, if you turn off the de-interlacer and any scaler present in the player then as near as dammit what goes out on the HDMI data port is what came out of the MPEG decoder, so the quality of the signal fed to the display device will be a function of transport/laser-tracking/decoding etc. .. of course, the final PQ will depend on the quality of the deinterlacer/scaler in the display.
     
  4. Jules Tohpipi

    Jules Tohpipi
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    Ahh.... right.....

    So, (de-interlacers and scalers aside) it's not just raw - off the disc - ones and zeros going to the plasma, but there's an MPEG decoding circuit in-between, working presumably in the digital domain. And, one might expect a cheaper DVD player to have a less good MPEG decoder than a more expensive player, so the more expensive player would have a better picture than its cheaper HDMI rival ?
     
  5. Galaxy

    Galaxy
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    Hi Lost Cause,

    Yes I do have the 500E and the Samsung 935 cabled via DVI, and am impressed by the picture quality, much "sharper" than my Sony 725 via component inputs, although having said that I did notice at the end of Pirates OTC that the end titles being a totally black background, had some very small colour noise, not noticed during normal picture playback at all, odd artifact actually, as if some of the RGB pixels within a certain area where active and not totally passive. I must qualify this statement though with the fact the noise was only visible from about three feet away, my son actually noticed it while while scrambling for the DVD case in front of the screen, so it is not a "problem" I am worried about.

    As to the technicalities of DVI/HDMI, I think Kragorn has covered it perfectly, basically the signal misses out the digital to analogue processing.

    Best regards David
     
  6. Galaxy

    Galaxy
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    If you read that article the 935 uses some very good chips from better (read expensive) machines too.

    Obviously I would think, or hope that if you pay ten times the cost of the 935 one would expect to see better picture! LOL
     
  7. Jules Tohpipi

    Jules Tohpipi
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    Cheers for that Galaxy. Interesting to hear you have the Samsung already and are getting good results from it.

    I heard that DVI and HDMI are compatible with each other, but at a glance, it looked as if the DVI connector on the back of the Samsung looks different to the HDMI connector on the 434's media box ? So, if I'm correct, I presume you were able to buy a DVI to HDMI connecting lead ? (Unless I'm completely wrong about the connectors being different !) I wonder if you could let me know where you got it from please ?
     
  8. KraGorn

    KraGorn
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  9. Galaxy

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    I didnt need a DVI > HDMI adapter cable as the hitachi 500E has DVI input socket as oppossed to the HDMI socket, and yes they are compatable, although the audio is not transmitted over the DVI connector (I believe this to be true) as on the HDMI standard.
    Of course this will not bother most people as the audio will be feed directly to an AMP via digital output from the player.

    Best regards David

    ps. the samsung amazingly came with a DVI cable.
     
  10. Jules Tohpipi

    Jules Tohpipi
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    Cool. Cheers again chaps.
     
  11. joys_R_us

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    The information on the disc is digital but not readily usable as it is encoded to save space. Hence not every frame is included and the data has to be processed before being output.

    It makes a difference what dvd player you use...
     

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