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Wont we need multiple HDMI inputs???

Discussion in 'General TV Discussions Forum' started by dilsher, Mar 19, 2005.

  1. dilsher

    dilsher
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    Ok gang..silly q maybe but i am new to this game.

    Come the time when we get our new Sky High Definition boxes and we buy a new HD DVD player with HDMI output..will the Plasma displays have more than one input to connewct up both ??? or is it a case of a switcher required???

    answers on a very fast postcard please..

    regards

    Dil
     
  2. Roohster

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    I was wondering about this myself.
    Havent seen any screens yet with two HDMI inputs, though when Panasonic sort out their act, we may see an "8 series" with plug in boards, so you can simply buy two HDMI boards.

    The new Viera 500 series is allegedly HDMI/HDCP ready but they've only fitted one digital input.

    The next generation of amps will have HDMI switching - some expensive models already have.

    I'd like to see amps with two HDMI outputs, so you can feed a plasma and a projector...as far as I know no-one is making an HDMI splitter yet.
     
  3. Starburst

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    The Philips DFR9000 amp which is mentioned on the front page of the HCC website has two HDMI inputs and a single output which would indicate that there is no technical reason a HD-DVD or Blu-ray device wouldn't also have the facility. Come to think of it recordable Blu-ray must have a HDMI input and a HDMI output so that would be one box taken care of.
    Somehow I don't think SKY+ HD will but it would certainly future proof the machine a bit but having said that I would suspect multipule HDMI inputs will become the norm (just as they are for scart) on the next generations of displays.
     
  4. hornydragon

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    HMDI splitters switchers and distribution AMPs all available....if you know where to look!
     
  5. dilsher

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    Good to know HD!!!

    Phewwww..

    Dil
     
  6. probedb

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    I guess this will take off as and when the connection becomes established :)
     
  7. Quickbeam

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    Don't Blu-ray recorders use Firewire rather than HDMI for recording MPEG-TS high-def broadcasts, and composite/S-VIDEO inputs for recording analogue SD signals?
     
  8. Starburst

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    The current Blu-ray recorder(s) on the market now can not be used as an example of what the mainstream mass market product will do since there is no wide spread retail pre-recorded discs on the market and thus no pressure from content suppliers for secure connections. SONY of course will be one of those content suppliers and along with other US broadcasters have made it clear HDCP via HDMI is the way to go.
    As for SD sources well who knows, it will probably be cost effective to include secondary video/audio inputs to cover all bases since there will be a market for optical recording of non High Def video.

    The use of Firewire is perhaps more a sign of the times, it was viable and had the capcity required and there were no real issues of content control since the numbers of recorders was so small and no real market for the product.
    Now that has changed and the global corporations are seeing a multi billion dollar hardware and software market being born and thus protecting that is paramount, HDMI is simple and includes the best level of protection and has been accepted from what I can see by everyone involved (Well maybe not the Chinese and other far eastern markets who are keen to develop their own hardware to avoid paying a few dollars for licensing).

    I don't know enough about Firewire to say what if any protection could have been layered onto it but the opporunity has gone, HDMI with HDCP is the standard for content protected digital media and that will be the norm of production/retail recorders.
     
  9. pdundas

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    Does the HDMI standard incorporate a method of sending a compressed digital bitstream (MPEG2, MPEG4 or VC-1) for recording? As far as I know it does not, as yet.
     
  10. Stephen Neal

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    Not sure - I think most (all?) of the BluRay recorders on sale are aimed at the Japanese HD market - and may contain integrated satellite receivers rather than firewire inputs.
     
  11. ahin4114

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    I was pretty sure the full standard for HDMI included audio, though none of the current sets/amps support the full implementation yet.

    Plus I believe that Pioneer have said their new 6 series panels will have 2 HDMI ports. Then of course, playstation 3 and Xbox 2 will take the requirement to 3!!
     
  12. pdundas

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    HDMI 1.1 includes multi-channel audio, yes. But that doesn't answer whether HDMI can deliver a compressed digital bitstream to a recorder.

    HDMI currently delivers the uncompressed digital video and audio. This is not a sensible way to record as we end up with:

    MPEG4 Compressed HD Signal -> decompression to full bandwidth signal over HDMI -> Re-encode to MPEG4 - > Write to disc.

    What makes more sense is:

    MPEG4 Compressed HD Signal -> Write to disc.

    Firewire currently carries the original compressed bitstream. My point is, as far as I am aware, the HDMI standard does not (yet, anyway).
    Decompressing and then re-compressing adds cost and more importantly has an inevitable quality loss.
     
  13. ahin4114

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    Perhaps, but you improve cross-compatibility which will inevitably be an issue with sending ready-compressed data. The minute the compression format changes (ala MPEG2-MPEG4) you have a redundant means of data transferral.
     
  14. pdundas

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    A bitstream is a bitstream so I can't see why that makes a lot of difference. As long as the recorder is designed to cope with whatever the transmission standards are then it should be OK. It's both a cheaper method and gives better quality so is win-win. You basically have the Blu-Ray recorder functioning in the same way as a Sky+ expect the data is written to an optical disc instead of a hard disk.
     
  15. Starburst

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    I would have thought so.
    After all why would the content of the digital data stream actually make any difference to the connection?
    I wouldn't think it did since why would the connection care if it was uncompressed video data or compressed data, the only thing that is important is that the data is compliant to the receiving device.

    Mind you the common sense approach is not always compatable with what the manufacturers and content suppliers take:)

    Even if it doesn't and the SKY+ HD sends a uncompressed data stream to the Blu-ray device via a HDCP HDMI connection then the data in compressed via mpegII or mpeg4 (as is done by TIVO and every other standalone DVD/Hard drive recorder) then perhaps that helps the studios.
    While the recording would still be very high quality it wouldn't be quite upto the standards of a retail release and therefore make paying for a genuine first gen copy more attractive.

    Until we see domestic/retail blu-ray or recordable hd-dvd products mass marketed at a viable price point then it's all guess work, well at least on my part:)
     
  16. ahin4114

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    On the surface of things that may be true, but what if the bitstream was a format that the player could not play back. It's a bit of a pointless comparison based on current technology, but the analogy is that you could stream an MPEG4 encoded bit stream to a deck that was only capable of playing back MPEG2. The encoded stream may well be written to the disc without error, but what's the point if you can't play it back?
    We don't know what new standards are going to be in 2 years time, a recordable deck should be able to record anything, even in ten years time, and therefore it should be designed to be as flexible as possible, that means it should always ensure that anything it writes it's capable of reading back. The only surefire way of doing this would be to encode it itself.
     
  17. Quickbeam

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    The idea of getting a Blu-ray recorder to re-encode high-def video is interesting, but as pdundas pointed out it's hardly ideal as it would degrade the video quality needlessly, and make high-def content easier to pirate. But how close are we to real time encoder MPEG-4 HD consumer encoder chipsets being ready? Sony's 1080i HDV camcorder has one of the first MPEG-2 HD encoder chipsets, but that wouldn't be ideal for Blu-ray as it would use up more disc space than a prospective MPEG-4 encoder. I think it will be a few years before MPEG-4 HD chipsets are ready. It will be interesting to see whether HDMI does finally emerge as the defacto standard for compressed bitstream recording.
     
  18. square_eyes

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  19. ahin4114

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    How does this differ from DVD recorders available now. They encode in exactly the same way as I describe, and I can see no reason why the industry would make it easier for an exact replica of material to be made. By making a home recorded picture less perfect than a pre-recorded one they will be ensuring that pirated material is not a perfect copy.
     
  20. pdundas

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    Because, in countries which already have HD, this is how it works (Bitstream recording) whether from two devices connected by Firewire or by a device with an integrated tuner. There is already a well established copy protection method (5C) for doing this. It is also easier to protect a digital signal (as long as the copy protection has not been broken) than an analogue one.

    If we have re-encoding devices then we have the depressing spectacle of a 2007 model Blu-Ray recorder unable to record a HD signal with as good quality as has previously been possible on a VHS tape. That's progress?!
     
  21. ahin4114

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    Rather an extreme example, would you say that existing dvd recorders only produce images equivelant to VHS? MPEG 2 encoders are capable of producing a very high quality image, assuming you have a high enough bit rate.

    It appears that your overlooking the main point of my post. I will add at this point that I'm not sure about how the bitstream recording/playback system works on existing D-VHS decks etc, I would assume that it's bi-directional. If you want to plug your Blu-ray deck directly into your display, then there must be a decoder on that deck capable of decoding whatever bitstream you have written onto the disk. Otherwise you end up having to replay the bitstream up a digital link to something that does have the relevant decoder, much the same way Sky+ works.

    It's the sama analogy that I can copy WMA files to a portable MP3 player and save them without any issue, but I can't play them back, becuase the deck doesn't have the right codec to play them.
     
  22. pdundas

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    I meant that you can currently make a perfect copy using a D-VHS or 1st generation Blu-Ray recorder so not to be able to do so in the future is a step backwards.

    The codecs of the forthcoming optical formats and HDTV are basically the same so it really should not be impossible to make a Blu-Ray recorder which takes broadcast stream and writes to a Blu-Ray disc in such as way as to make it playable in all Blu-Ray devices. At the moment it is not difficult to write a MPEG2 broadcast stream to a DVD in such as way to make it fully DVD compliant so I can't see it as that big a hurdle to do it with HD.

    I would also disagree that the quality of current DVD recorders is good enough. I have one but hardly ever use it because I find the quality even at high rates surprisingly poor. I can see the difference on a 32" SD TV but it is probably acceptable to most eyes, up this to large displays or projectors and the quality drop is quite severe.

    To me it just seems a shame that in a future world of HD and 1080p display devices all connected digitally we could end up with a quality losing encode/re-encode part in the recording chain which is actually a step back from the current HD recording solutions.
     

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