1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

DVI, HDMI - Explanations for a novice please?

Discussion in 'General TV Discussions Forum' started by Phil from 62, Jun 15, 2005.

  1. Phil from 62

    Phil from 62
    Standard Member

    Joined:
    Jun 14, 2005
    Messages:
    59
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Location:
    Essex
    Ratings:
    +0
    :confused: This whole HD TV thing on the horizon is a bit foggy to me. Although I understand its advantage and worth the difference in connectivity and standards confuses the hell out of me.

    I read one magazine article and think I've grasped it, then read another that sheds doubt over my understanding.

    DVI, as I understand, will deliver image signal only? If so how do you get your sound source? HDMI does both sound and images...so why have DVI?
    What is the best connectivity to have on any new equipment?
    Also most equipment, as far as i can see, are only currently being manufactured with one HD connection...is this not akin to a current TV, say, only having one scart?

    Is this not a good time to buy into the HD market? Is it best to wait?

    Sorry so many questions, but I see each question as part of a puzzle I can't totally piece together.


    HELP!!! :lease: :confused:

    Equipment (at the Mo): ARCAM AVR100, ARCAM DV88 DVD, crappy old CRT TV (my next change and possible step into the LCD market)
     
  2. foz

    foz
    Standard Member

    Joined:
    Apr 23, 2005
    Messages:
    131
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +1
    with dvi equiptment you will either use red and white phono leads to tv or optical/digital coaxal to amp.dvi means you can connect direct to a pc graphics card for digital input(although you can convert to analogue and use 15 pin d sub anyway)you can buy dvi-hdmi leads so no worrys so long as your tv has hdmi.you can also buy hdmi switching boxes that allow you to have either 2,4,6 or even 8 hdmi inputs to 1 or 2 outputs.mabey future tvs will have 2 or more hdmi sockets wh knows?
     
  3. AML

    AML
    Well-known Member

    Joined:
    Jul 22, 2004
    Messages:
    4,989
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Tokyo
    Ratings:
    +228
    DVi was arround before HDMI and wasnt designd for sound. It was designed for Digital picture.

    If you have a home theater im sure you can appreciate wanting to keep sound and picture sepparate.

    HDMI is much newer and is designed to bring digital sound and picture together to make things more simple.

    The best conection to have from now on will be HDMI as it should become the standard for HD equipment.

    If you buy a TV with HDMI you should be safe, but bare in mind that you will eventually need a 5.1 or higher digital decoding amp to decode the digital sound stream.

    Most TVs wont do that for you. They will only give you the picture.

    So in essence having a single cable that does both sound and picture is redundant as you will need a second cable going into your amp for sound. :rolleyes:

    The way it will probably work is that you will have a single HDMI cable coming out of your player (blu ray or HD-dvd) and into your amp, then a second one coming out of your amp and going into your TV.

    If you are using DVi then you will need a audio cable like optical or coaxial coming out of the player and into an amp.

    Personaly i preffer to keep sound and picture sepparate.
     
  4. NicolasB

    NicolasB
    Well-known Member

    Joined:
    Oct 3, 2002
    Messages:
    6,367
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    136
    Location:
    Emily's Shop
    Ratings:
    +844
    Doubtless - but it's important to have some form of industry-standard high-bandwidth digital audio connection. It looks like it's going to be HDMI rather than Firewire. Bundling the audio and video also allows you to switch both with the same switching device.
     
  5. cerebros

    cerebros
    Active Member

    Joined:
    Dec 27, 2002
    Messages:
    1,262
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    38
    Location:
    Leicester
    Ratings:
    +21


    Because DVI started out as a computer connection between graphics card and monitor, so there was no need for sound. However, when we started getting fixed pixel displays like plasma and LCD which could take digital input from computers some manufacturers started putting DVI out on their source devices (i.e. DVD players) so that end users could take advantage of what should, in theory (i.e. barring poor implementation), be perfect transfer of the picture information in the digital domain between source and display.

    HDMI equipped source devices are still quite rare, while there's still a valid space for including a DVI on the TV as there's every chance it will be hooked up to a PC or HCPC, which won't have HDMI connectors, but will more than likely have a DVI. That's why you'll probably see DVI on flat panel TV's for a while yet (although I understand there's a new connection standard being devised for the computer market which will supersede it)
     
  6. Colman

    Colman
    Standard Member

    Joined:
    Jun 15, 2005
    Messages:
    5
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    3
    Ratings:
    +1
    I'm also quite new to this. My setup will soon require me to feed an HDMI lead (from the new High Def Sky box) to my TV for pictures, but my audio needs to go to a separate amplifier which provides Dolby Digital decoding, which will no doubt go via phono leads (along with an optical lead for DD). My question is, does the HDMI connection introduce any delay to the video, which will make my audio out of sync?

    Colman
     
  7. cerebros

    cerebros
    Active Member

    Joined:
    Dec 27, 2002
    Messages:
    1,262
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    38
    Location:
    Leicester
    Ratings:
    +21
    As AML has said, the optimal option in the HDMI enabled age would be to take HDMI from your HDMI enabled source (DVD player, HD-DVD/Blu-Ray player, Sky HD decoder) straight to your amp and then use the amps HDMI output to your TV so you get the picture.

    You shouldn't have any need for phono leads if your amp doesn't support HDMI switching - an optical or coax cable will suffice.

    I wouldn't have thought it highly unlikely that HDMI would introduce any delay if you're connecting straight from source to screen, or routing audio and video into the amplifier. You'd probably get delay if you were running the video through a scaler, but your amp will have an audio delay setting anyway which should allow you to compensate.
     
  8. Petrushka

    Petrushka
    Active Member

    Joined:
    May 23, 2005
    Messages:
    212
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    21
    Location:
    Hoofddorp NL
    Ratings:
    +5
    Sorry for cutting away part of your post, which was quite clear. Thanks!

    However, I am one of those who wants everything combined as it makes everything much easier to connect and operate. Also, I would like my AV receiver to act as control center, distributing the incoming signals.

    The reason being that I have / will have multiple digital (HDMI) sources, like sat-receiver, cable receiver, DVD/HD recorder, (inter-)network client (multimedia receiver), and last but not least a game console.

    I would want to connect all of that to the AV receiver and then forward the signal to the plasma, which also has HDMI. This leads me to the following question:

    Obviously I also want a cable between AV-receiver and HD/DVD recorder so I can record from various sources. Just like we used to do when HiFi audio was still purely audio. You would record from a tuner or a record player or a casettedeck onto a tape deck and all signals would flow through the amplifier.

    I would like to have a the same flow for the AV combined signal. Multiple sources connected to the receiver, one HDMI output to the screen and...

    Now what? Is an HDMI connection bi-directional? I.e. if I have a HDMI cable between receiver and recorder, can I also record, or will I need a second cable between amplifier and recorder? If the latter, then why don't the recorders have HDMI inputs. If the former, then why are HDMI ports on recorders always specifief as output connections?
     
  9. quig

    quig
    Standard Member

    Joined:
    Jan 17, 2004
    Messages:
    20
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Ratings:
    +1
    Current consumer level recording devices are not able to record signals from HDMI. These signals use very high data rates, so it would be impractical to store them on a recording device without compression.

    Compressing the high bandwidth signals from a HDMI output requires more processing power than is available. Adding another compression cycle is also detrimental to the picture quality, so is undesirable.

    Current devices in the USA may be hard disk based, and integrated with a satellite, cable or terrestrial set top box receiver, so can record broadcasts directly, without needing the processing power required to compress high definition video.

    They may also feature a IEEE 1394 (firewire) interface, such as D-VHS recorders. These devices also record the broadcast MPEG2 stream from the firewire input intact, so do not re-compress the signal unnecessarily.

    In the case of Sky's HD service, as all set top boxes will have an integrated hard disk, recording using external devices will probably not be possible, as there may not be a firewire output. It is even less likely that HD-DVD and Blu-ray devices will have a firewire output, for copy protection reasons.

    Only non-Sky broadcasts will likely be able to be recorded with an external recorder such as Blu-ray, HD-DVD or D-VHS. It is possible that this will be the case with BBC channels, but the BBC has as yet confirmed no plans to start broadcasting in HDTV. It may be possible to record Euro1080 broadcasts and the output of high definition consumer camcorders to Blu-ray or HD-DVD, but whether the devices will feature firewire inputs is questionable at present.
     
  10. AML

    AML
    Well-known Member

    Joined:
    Jul 22, 2004
    Messages:
    4,989
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Tokyo
    Ratings:
    +228
    Comprehensive!

    Its true that at the moment its not looking like we will be able to use HDMI as a source for recording.

    One reason will be digital content copy protection.

    I see HDMI as being a one way system designd to conect future HD hardware.

    One probelm i see at the moment is that most new amps and TVs dont have more than 1 or 2 HDMI conections. Thats gonna make it hard to conect all these different surces in the future.

    Anyway, im sure some one will make a decent cheap switch box for HDMI.

    As for recording, PCs or analog cables.
     
  11. Joe Fernand

    Joe Fernand
    Distinguished Member AVForums Sponsor

    Joined:
    Jan 20, 2002
    Messages:
    26,219
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    The Borders
    Ratings:
    +2,933
    Hello all

    A lot of good points already covered so I'll try not to go over old ground.

    A coupe of pointers:

    HDMI - can transmit both Digital Video plus Stereo or Multichannel Audio. NOTE the CAN bit - there are a lot of HDMI Source and Display devices out there that jumped in early and can ONLY Transmit/Receive Digital Video or Digital Video with Stereo audio; don't assume every HDMI equipped device is full spec; there are allowed sub sets of the HDMI standard.

    DVI - conceived for the PC industry so no support for Analogue or Digital Audio.

    DVI-D is an all Digital Video connectivity standard and DVI-I offers support for Digital and Analogue video.

    HDMI to DVI - as long as the DVI receiver chip in the Display, Projector etc is HDCP compliant you can mix and match these two standards for high quality Digital Video connectivity. Non HDCP DVI receiver chips will reject any Copyrighted material being output from an HDMI source which automatically apply the HDCP encryption when flagged to do so by the DVD disc or Broadcast stream.

    HDCP encryption - this is what its all about. Not as the marketers would like us to believe 'Pristine' Digital Video transfer; all of this shift to Digital Video is purely to introduce a more secure Copy Protection and Digital Rights management system.

    Digital Video and Audio paths - it'll be a while before we see a range of AV Receivers with full Bi-Directional implementation of the HDMI standard and until then your looking at all sorts of combinations of HDMI for Digital Video plus Stereo Audio plus Coaxial and Optical for Multichannel Audio, HDMI for Digital Video Plus Multichannel Audio plus Coaxial and Optical for Multichannel Audio... and that's before you start to factor in what to do with SD and HD on the same Video path and the ability to record SD sources via an all Digital pathway but not HD on the same pathway even though you can view both SD and HD on your Display etc

    For now your most likely to be looking at adding Digital Video connectivity, switching and distribution to your system using a dedicated Digital switching solution that can work in tandem with the Audio and Analogue Video switching of your AV Receiver; Zektor and Gefen have a range of products to add this functionality to most system already.

    The problem with a 'one box' solution is that they invariably don't cover all the bases for every owner - we've had folk return the likes of Pioneers 'Flagship' VSA-AX10Ai because even as sophisticated as it is it failed to offer certain combinations of switching, distribution, conversion we could achieve using a lower spec AV receiver plus an external switcher, distributor and still offer as 'seamless' a system using a programmable remote for a comparable budget.

    Best regards

    Joe
     
  12. Phil from 62

    Phil from 62
    Standard Member

    Joined:
    Jun 14, 2005
    Messages:
    59
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Location:
    Essex
    Ratings:
    +0
    Thanks everyone for your input, advice and opinions etc.
    What with this info and scouting around the Forum I believe my understanding, base knowledge and perceptions have improved 100%.

    All I can say, as with any technology and fast moving industry, what a minefield.

    Bearing in mind that I would assume that the vast majority of people on here are enthusiasts....what hope is there for high street buyers walking into the high street retailers with staff of little experianced and knowledge as AV in general and HD takes off evn more.

    Thanks again
     
  13. AML

    AML
    Well-known Member

    Joined:
    Jul 22, 2004
    Messages:
    4,989
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Tokyo
    Ratings:
    +228
    Yep it is geting harder and harder to understand whats happening.

    Companies make all this effort to bring out new products and market them in the way they want, but they never make any effort to educate people on the benefits of these new prosucts.

    I would like to see companies paying for seminars designed to teach stores and store assistants how their new products work. Not just the good points either.

    Then i would like to see these assistants be able to give customers and objective and impartial view on the new product.

    I noticed that in many shops they just regurgitate what they have been told to tell customers in order to sell something.

    Thats my experience anyway. Most of these fools dont know anything and all they care about is making a sale.

    I find myself looking into something before I go into a shop and just buy what i want directly without asking for assistance.

    Because of that i also find myself buying things online to save time and money. After all why should I pay extra at a shop that knows nothing?

    They only have themselves to blame if they loose customers to the net.
     
  14. PinkPig

    PinkPig
    Standard Member

    Joined:
    Feb 14, 2005
    Messages:
    98
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Ratings:
    +0
    This is a bit of a silly question - but, in theory, and if someone decided to do it, would it be possible to use a DVI output from a DVD player to connect to a PC monitor with a DVI input? What sort of image quality would it give? Just wondering, really......
     
  15. ianh64

    ianh64
    Active Member

    Joined:
    Aug 7, 2004
    Messages:
    2,233
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    SW London/Surrey borders
    Ratings:
    +63
    You would probably be faced with two problems:

    1. HDCP. The output from a DVD player will possibly be HDCP encrypted. A PC DVI monitor will probably not display a HDCP encrypted signal.

    2. The output from a DVD player will probably output DVI-Video level (16..235) signals. A PC monitor would likely expect DVI-PC levels (0..255). The result of this would be that blacks and whites will not be full level, so the picture would lack contrast.

    -Ian
     
  16. Stephen Neal

    Stephen Neal
    Well-known Member

    Joined:
    Mar 29, 2003
    Messages:
    6,259
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +763
    Presumably this is also an issue with Media Center PCs? AIUI they also use 16-235 for their video - as that is the broadcast standard used on DVD and Freeview (rather than remapping to 0-255)
     
  17. AML

    AML
    Well-known Member

    Joined:
    Jul 22, 2004
    Messages:
    4,989
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Tokyo
    Ratings:
    +228
    All i know is that there are 3 or 4 types of DVi.

    DVi-i (digital and analog)
    DVi-D (digital only and used with HDCP on new HDTVs)
    DVi-A (analog only. Not really used anymore)

    There may be another but not sure.

    Theres also the Dual and Single types you need to think about. Dual offers slightly higher resolutions and is supposed to be the best for Hi def stuff. Finding Dual DVi-D cables is hard though. They can be expensive and not many companies make them.
     
  18. Dutch

    Dutch
    Well-known Member

    Joined:
    Dec 5, 2002
    Messages:
    2,601
    Products Owned:
    2
    Products Wanted:
    5
    Trophy Points:
    106
    Location:
    North Yorkshire
    Ratings:
    +284
  19. Joe Fernand

    Joe Fernand
    Distinguished Member AVForums Sponsor

    Joined:
    Jan 20, 2002
    Messages:
    26,219
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    The Borders
    Ratings:
    +2,933
    Hello all

    Dual Link DVI has the ability to carry up to 2048x1536 resolution signals - which only a very very few high end graphic workstations and dedicated high resolutions Monitors will handle; Dual Link is only enabled on dedicated hardware.

    Single Link DVI has the ability to carry up to 1920x1080 resolution signals so is more than up to the job of any current SD or HD signal in Hone Theatre land.

    We have some 9m and 5m Dual Link BetterCables Display Magic DVI cables on offer in the AVForums Cables Power Buy section :)

    Best regards

    Joe
     
  20. Welwynnick

    Welwynnick
    Well-known Member

    Joined:
    Mar 16, 2005
    Messages:
    7,113
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Location:
    Welwyn, Herts
    Ratings:
    +837
    I believe that the great majority of cables and connectors are dual link DVI, which still work with single or dual link equipment.

    Howerver, AV devices generally implement single link, as that is sufficient for what they use, but they can still use single or dual cables .

    A rare glimmer of common sense: it would be tragic if it were the other way round.........

    But I guess the thing to watch out for would be trying to fit a DVI-I plug into a DVI-D socket, which will not have enough holes.

    Nick
     
  21. Stephen Neal

    Stephen Neal
    Well-known Member

    Joined:
    Mar 29, 2003
    Messages:
    6,259
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +763
    AIUI single link connectors can have a gap in the middle of the the two groups of 9 pins (i.e. an 18 pin connector), with dual link connectors having an additional 6 pins in the middle (to create a 24 pin connector)

    This is ignoring the analogue section at one end.

    The extra 6 pins can carry a second, parallel, stream of digital video, allowing more "pixels" to be pumped out a second, and thus higher resolutions?
     

Share This Page

Loading...