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HDCP? please explain

Discussion in 'TVs' started by steves1923, Aug 17, 2005.

  1. steves1923

    steves1923
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    Ok, I have had so many different explainations about HDCP and its purpose that I still have no definitive answer. I know that the tv and player both need it to talk to one another and echange certain "keys" to keep communication open and the data in the digital domain. But what for. Is it purely for upscaling or copy protection matters. Does this mean that if I dont have it on one of my devices will I not be able to see the data, or not be able to record onto my PVR.
    I appologise if this is basic knowledge but I think that there is a big grey area regarding this technology that needs to be explained to the beginner to medium knoledge group.
    Thanks in advance
    SteveS
     
  2. Tony Hoyle

    Tony Hoyle
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    The purpose of HDCP is entirely for encryption (although there's some convenience to be gained by putting the audio on the same connector).

    In a fully HDCP compliant system you would not be able to get at the data for recording - your PVR could only record what the content providers had chosen to let you record, and nothing else (probably just a long stream of adverts).

    Also in a fully locked down system non-HDCP devices would be rendered useless.

    Luckily that's a worst case and probably won't happen.. it's what some companies want but the buying public are a bit smarter than that.
     
  3. steves1923

    steves1923
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    Hi Tony.
    So are you saying that if I dont have a HDCP tv and play something through my HDCP DVD player, if the content is encrypted I will not be able to see it? or maybe just not upscale it? (HDMI)
     
  4. Tony Hoyle

    Tony Hoyle
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    If you have for example an HD-DVD which uses HDMI (and HDCP) exclusively, you will not be able to use a non-HDCP compliant TV with it.

    There's some indication that you might be able to get an SD (480i) feed out of such devices, but there's little point in having one if you're going to do that... just get a cheap DVD player from Argos that does the same thing.
     
  5. steves1923

    steves1923
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    So this relates back to not allowing the upscaling of the 480i through the HDMI connector to a non HDCP Tv.
    Is this the only benefits of having HDCP, to allow upscaling to better resolutions?
    Can upscaling be done without HDCP i.e having an non HDCP TV and HDDVD?
     
  6. Tony Hoyle

    Tony Hoyle
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    It's got nothing to do with upscaling or resolutions.. it's all to do with using encryption to force you to use compliant devices.

    You cannot connect an HD-DVD to a non-HDCP TV. In the future, Sky HD may start using their HDMI connector so it'll eventually be impossible to watch Sky through a non-HDCP TV (or record it on a PVR or VCR)... that's a few years off I expect.

    The option of getting an SD feed (which is downscaling, not upscaling) is only a rumour and may not pan out.
     
  7. steves1923

    steves1923
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    Ok, Thanks Tony for your input. You have explained well
    Sorry if it was a basic concept but I really believe that not all "professionals" eg sales people, have a grasp on this technology. Maybe a post explaining this concept in layman's terms and examples of different situations would be of benefit to these guys.
     
  8. Tony Hoyle

    Tony Hoyle
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  9. binbag

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    HDCP (High-bandwidth Digital Content Protection) is a specification developed by Intel Corporation to "protect" digital audio and video content as it travels across Digital Visual Interface (DVI) or High Definition Multimedia Interface (HDMI) connections. The HDCP specification is proprietary and implementation of HDCP requires a license. It is a form of Digital rights management.

    HDCP is licensed by Digital Content Protection, LLC. In addition to paying fees, licensees must also agree to limit the usefulness and interoperability of their products by restricting outputs and lowering the quality of reproduction on some interfaces such as speaker cables. Licensees cannot allow their devices to make copies of content, and must design their products to "effectively frustrate attempts to defeat the content protection requirements."
    :nono:

    Wikipedia (icon by me)
     
  10. steves1923

    steves1923
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    What about the new players that have WMV9 or D:vx HD playback. e.g. Z500 from Zensonic. www.z500series.com. This player has hdcp through HDMI
    I am assuming that these will not get affected whether you have an HDCP TV or not for these types of files? If I connected this machine to a non hdcp tv and played a regular dvd will I get anything?
    Also if you cant connect non hdcp gear with gear that has hdcp, wont that mean that there is going to be a lot of useless gear out there in the coming 12 months as HDMI becomes more popular or will it just restrict the content for some people?
     
  11. Tony Hoyle

    Tony Hoyle
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    Yup. There will be a lot of useless kit with the next year or two, if the record companies have their way. OTOH there are already boxes to strip HDCP from the video signal and I can't see those going away.

    WMV9 with DRM will presumably not play without HDCP on the Z500 (one of the conditions of the HDCP license apparently is you disable all nonprotected outputs on protected video). You can of course play it on a standard PC anyway..
     
  12. steves1923

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    By "disabling noprotected outputs" do you mean that they disable playback from all other outputs on the machine including svideo, composite and componant?
    This seems rather extreme as I thought it was only meant to protect pure digital signals and not analogue.
     
  13. binbag

    binbag
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    I've always taken this to mean that a device won't allow a protected source to be converted to a non protected output while that source is active. Put simply, it won't output to anything other than the HDMI when given a digital source.

    And as someone who's planning to go SDI to VGA next year and looking to pick up a used panel VERY cheaply I say bring it on!
     
  14. Welwynnick

    Welwynnick
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    The HDCP license requires that any equipment that can generate an HDCP protected HDMI or DVI output must disable any analogue outputs.

    Rotton sports.

    Nick
     
  15. ianh64

    ianh64
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    I don't think that is strictly the case - my DVD player does component, composite, s-video simultaneously with HDMI out. It is fully licensed so is not trying to break any rules.

    What I believe HDCP does forbid is the simultaneous output of copy protected scaled or high definition content. So the non HDCP outputs can be active, but only at SD/progressive resolutions.

    -Ian
     
  16. steves1923

    steves1923
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    This seems to make more sense to me as the definition of HDCP (or rather its reson for being) is to protect the pure digital source from being throughput and copied.
    So am I right in saying that it is not to totally stop people watching the content but to inhibit HD and upscaling if you dont have compliant devices?
     
  17. MeatSim

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    Is HDCP a hardware feature built on to the device which is always working or a software feature? (which in theory could be switched off and no)

    and what happens when you try and go the other way? for example if you have a tv with HDCP over DVI and you connect a player that has a DVI out but no HDCP is the TV able to display the image since it would be expecting the DHCP key or is it able to realise that the key isn't there and just not use HDPC?
    (that is a very bad way of explaining it i'm sorry)

    or is it that in a HDCP setup everything must support HDCP for it to work?
     
  18. binbag

    binbag
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    I have a HDCP PJ and a non HDCP DVD; via DVI-D it gives a lovely picture.
     
  19. Joe Fernand

    Joe Fernand
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    Hello MeatSim

    In theory the HDCP encryption on HDCP compliant source devices is triggered by the content - be it a pre recorded disc or an MPEG stream from a broadcaster (and soon enough an MPEG stream from your PC's hardrive as HDCP is on the way in the PC market too).

    Some source devices simply whack HDCP on to everything - which is obviously problematic!

    An HDCP compliant Display device will work with and accept non HDCP content from a non HDCP complaint Source device - hence the availability of 'work around' boxes that Input a Digital Signal with HDCP and Output a Digital Signal with the HDCP 'stripped'; the manufacturers of these products have NOT signed up to the HDCP Licence agreement from DCP, LLC so these products are not strictly 'legal'.

    See http://www.digital-cp.com/home

    Best regards

    Joe
     
  20. Welwynnick

    Welwynnick
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    HDCP is probably implemented in firmware, but that will not significant. The important thing is that it certainly CANNOT be switched off. The Microsoft designers will have been wise to the fact that service menus become public over time, and they have to anticipate the stongest hacking efforts of many clever and resourceful people. They will be mindfullof the rapid cracking of DVD copy protection, and will try to ensure it won't happen again. Spoilsports.

    HDCP will only be enabled when required by the source and the display and the copyrighted status of the material. Not all material will require HDCP to be enabled - that will be for the copyright holder to specify. But any studio releasing an HD film on HD-DVD or Blu-Ray will surely require this.

    Not all HD displays are HDCP capable, but they will still be able to show unencrypted material, even if the source is HDCP capable.

    If the source is not HDCP capable, but the display is, then the display will be able to show any material that the source can play, notwithstanding any other technical incompatibilities.

    Nick
     
  21. Joe Fernand

    Joe Fernand
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    Nick

    In a DVD player HDCP is triggered by the same 'Flag' that triggers Macrovision - the Flag is on the Disc and once the Player reads that Flag HDCP handshaking is initiated.

    For some folk the frustration or first indicator of something being amiss will be when they stick a disc in an HDCP complaint Player (attached to the non HDCP DVI Input on a Display) - the 'adverts' will play fine (no HDCP) and look excellent and then as soon as the Movie credits roll the picture will simply drop out when the player reads the Macrovision flag.

    Best regards

    Joe
     
  22. steves1923

    steves1923
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    In this scenario, will you be able to watch the movie in HD through your component?
     
  23. Joe Fernand

    Joe Fernand
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    steves1923

    Most likely not - assuming your Up-scaling or HD player also has YUV outputs that are active when your in HDMI mode if the HDMI handshake doesn't happen you wont get an Image from any output on the player.

    You would have to re-set the player in its user menu to YUV out and on most players that will disable any up-scaling or HD output via YUV.

    Even when you have HDMI initiated your up-scaling or HD player is unlikely to output a simultaneous HD YUV signal;
    look at Denon's 'Flagship' DVD-A1XV for example - even if you have HDMI Initiated with a suitable Display and the Players on-board Up-conversion set to 720P or 1080i invoked the YUV Outputs only ever Output a 480P or 576P signal.

    See http://www.denon.co.uk/site/frames_main.php?main=prod&ver=&MID=3&sub=1&action=detail&Pid=176

    Best regards

    Joe
     
  24. steves1923

    steves1923
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    I wonder how long it will be before all dvds, hd or not will have hdcp encrypted on them making a lot of peoples equipment useless.
     
  25. MeatSim

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    Hi Joe,

    Thanks for that, if it is just a flag then one would presume it is only a matter of time before we start to see the option to "remove HDCP" in burning software so people who don't have a HDCP setup but buy a disc with HDCP come copy there own discs to allow them to play.

    i'm sure that that isn't really legal but that has never stopped people before
     
  26. ianh64

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    HDCP encryption is not on the disc. HDCP encryption is added by the source player when it detects the copy protected flag on the disc. As Joe says, this is the same flag that triggers macrovision on analogue outputs and is on the majority of DVD's that have ever been produced.

    There is no reason why a DVD player using HDCP encrpyption should not have simultaneous output at SD resolution on analogue output thus allowing legacy equipment to still be used. Of course, if you wish to utilise HD or upscaled material, then you will need a HD display that has a digital input with HDCP.

    -Ia
     
  27. steves1923

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    Hi Ian,
    Thanks for clearing that up. I think that its finally starting to sink in :clap:
    There still seems to be some confusion however whether we will be able to get any content pass through when there is no HDCP handshaking albeit SD through any other output other than the DVI/HDMI, or whether it gets totally blocked.
     
  28. Joe Fernand

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    Hello MeatSim

    It will be better for most folk to leave the 'On-disc' Flag intact and deal with the HDCP encryption on the Output stage of the Player - otherwise if you have a player with 'up-conversion' and want to use that facility the 'up-conversion' option will not be allowed on non flagged discs.

    There is already a growing list of hardware vendors producing DVI (with HDCP) to DVI converters and DVI (with HDCP) to VGA or YUV converters.

    If you have a DVD player that is HDMI enabled (up scaling or not) and don't have an HDMI or DVI (with HDCP) input on your Display then you simply set the player to output Composite, S-Video, RGB or YUV (whichever is available and optimal for your system) and you'll get an Interlaced or Progressive non scaled output on one of the Analogue outputs.

    What will happen with a true HD source is still unclear (to me) if there is an Analogue Output provided you should be able to connect a Standard Definition feed to your non 'HD Ready' Display and definitely view conventional DVD's on the HD Player though I'm not sure if the hardware vendors MUST also provide an SD feed from an HD source disc; time will tell I guess.

    Best regards

    Joe
     
  29. GalileoFigaro

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    Hopefully a quick question:
    Why do some HD Ready TV manuals not mention HDCP?
    I might expect it where the set has a HDMI socket because my understanding is that HDCP is implied by that. However, when a TV has a DVI socket - e.g. Philips 32PF7520D - why not mention in the manual that it copes with HDCP?
     
  30. Starburst

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    DVI does not have to include HDCP so the manual may not mention it since a particular model does not have that feature.

    I can't speak for that particular model but my Philips lists HDCP via DVI on a seperate specification sheet and also the website.
     

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