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HDMI and DVI

Discussion in 'Projectors, Screens & Video Processors' started by zamwessell, Jun 1, 2004.

  1. zamwessell

    zamwessell
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    I have read some reports that HDMI is superior in visual quality to DVI.

    If this is true,surely it must marginal.

    I was about set with my future purchases....HDMI dvd player,DVI projector,HDMI to DVI convertor cable and when they are available..30"+ LCD tv with HDMI input.

    Now i am having doubts about buying a DVI only ( No HDMI input ) projector.I would have thought the HDMI to DVI convertor would sort things out ?
     
  2. RTFM

    RTFM
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    DVI is fine. As long as the input is HDCP compliant you won't have any problems.
     
  3. rscott4563

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    When transmitting the same type of signal, progressive RGB 4:4:4 both connection are the same, the only benefit of HDMI is that it can also transmit Component at both 8bit 4:4:4 and 12bit 4:2:2, also HDMI can be interlaced as well as progressive but DVI can only transmit progressive. This means that with DVI your limited to the de-interlacing of the source device, however good or bad that maybe..

    Also another reason for going with HDMI at least in the display device is that you can have longer cable runs if the receiver is a HDMI device as these support cable-equalization, so a DVI - DVI setup would have DVI cable length limitations, whereas a DVI/HDMI - HDMI setup would have the longer HDMI cable limitations.

    Cheers

    Ryan :thumbsup:
     
  4. zamwessell

    zamwessell
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    I would be connecting a HDMI dvd player to a DVI projector.
     
  5. satlogic

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    Apparently DVI cable run can be 5 metres, whereas HDMI is 15metres.
     
  6. RTFM

    RTFM
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    If only it were that simple.
    A lot of factors come into length of cable runs. Probably one of the most important being the strength of signal from the DVD player. Also cable geometry, construction and materials will play a big role. Within that you have the impedance, inductance and capacitance of of cable, source, and display device to consider

    Jeff :rtfm:
     
  7. JohnWH

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    I think the "official" limit on DVI is 7.5m, for HDMI I think its 9.5m.

    This said, I'm running DVI over 10m with a cheapo Lindy cable (2x5m ones actually). I don't appear to be having any issues when driven from the DVD player (samsung 935), although my PC shows some definite signs of intermitant pixel drop out at that distance.

    John.
     
  8. Mark Ward

    Mark Ward
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    Another factor to consider is whether your PJ will support your chosen resolution via HDMI.

    For example, my HS20 doesn't support HDMI at the native panel resolution meaning that 1:1 pixel mapping isn't possible by HDMI.

    I now have a 9M DVI Better Cables from The Media Factory that works perfectly.
     
  9. Ali K

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    "Also another reason for going with HDMI at least in the display device is that you can have longer cable runs if the receiver is a HDMI device as these support cable-equalization, so a DVI - DVI setup would have DVI cable length limitations, whereas a DVI/HDMI - HDMI setup would have the longer HDMI cable limitations."

    Ryan,

    This was something I have been thinking about but haven't been able to find solid info on. I've invested a rather large sum of money in a 12m Monster DVI cable for my HS20 which I am currently running off my PC as I am still undecided on a player, from what you've said it appears that I would be safer with HDMI, is that correct? Could you point me to where you've got your information on the DVI-HDMI issue?
     
  10. rscott4563

    rscott4563
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    The infomation was gained from Jim Peterson, he is the founder of Lumagen who make top notch video proccessors. He discussed this point in a thread over at the AVS forums and he stated that he had got his information from Silicon Image who are the company which produce the DVI and HDMI chips.

    I'll try and find the specific posts...

    See link here
     
  11. ukaudiophile

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    Hi,

    The big thing to check here is that the DVI equipped projector supports HDCP. If you have a HDMI source with a DVI receiving device which doesn't support HDCP, then you will probably have problems because the security protocols can't handshake. The HDMI and DVI with HDCP receiving chip has a code in it which tells the transmitting device it is safe to transmit the data as it is a secure receiver. If this handshaking doesn't take place, then the transmitting device will not pass through data and the link won't work.

    The good news is that a lot of DVI equipped projectors do support HDCP, but not all of them, especially the early DVI equipped projectors, so it's worth checking.

    At the end of the day this is surely only going to be a temporary situation, as I'm sure in the near future a Taiwanese or Chinese factory will figure out how to emulate the HDMI of HDCP handshaking in a chip which they'll put in a £150 DVD recorder, and at that point the whole system's integrity will fail, but until then it is a secure system.

    Best wishes,

    Dave
     
  12. Ali K

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    Thanks for the prompt reply Ray, much appreciated.

    I am just getting around to formatting and installing new software on my PC, it'd be interesting to see if I'll have artifacts driving the HS20 at native resolution on a 12 m DVI cable.
     
  13. Richard Harnwell

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    Ali,

    Have you had chance to get this installed & hooked up yet? If so, what is the max resolution you are running at (native panel?), and have you noticed any problems?

    This is about the length of DVI and HDMI cables that I'm going to need for my HS20. I'm going for a DVI cable first, as I currently have no way of connecting up my PC to my projector (after upgrading from a 10HT where I just used lots of RG59 cables for everything!)

    If yours is working fine, then I think I'll break open my piggy bank!

    Cheers,

    Richard
     

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