HD DVD and 1080i

Discussion in 'Playback Devices' started by Chris Huber, Jun 21, 2006.

  1. Chris Huber

    Chris Huber Second Unit

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    Hey guys, I've been reading all the threads on you guys being able to watch/buy HD-DVD players... Good info for sure!

    Everyone seems to Think that an HD Cable feed switched over to a HD DVD 1080P feed is amazing in the difference...

    There are a lot of people who have HDMI TV sets with only 1080i displays...
    My question is, what about 1080i? Has anyone actually seen 1080i HDMI from a HD-DVD player? How does it look? Any experiences you can share?
     
  2. ChristopherDAC

    ChristopherDAC Producer

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    Everyone running HDMI from HD DVD is getting 1080i, since Toshiba did not include the capability of generating a 1080p output in their hardware.

    It's not clear whether the users of Blu-Ray are getting a "real" 1080p output from the Samsung player, decoded and passed through at the original resolution, or whether that player's 1080p HDMI output is internally reconstructed form a 1080i signal, itself broken down from 1080p in the first place. If the latter, one wonders if the reports of bad picture quality on early titles mightn't have something to do with the video processing, in which case 1080i via HDMI or component might be an improvement over 1080p!
     
  3. Dave H

    Dave H Producer

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    Now, if someone owns a 1080p display, can't they get just upconvert the 1080i HD DVD to 1080p for about the same result?
     
  4. Chris Huber

    Chris Huber Second Unit

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    Wow, I missed that; so everyone reviewing HD-DVD is watching 1080i?
     
  5. Walter Kittel

    Walter Kittel Producer

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    Yep, and it looks splendid. ( Didn't respond to your initial query since I am using component. ) Best images I've EVER seen on my projector. My FP doesn't support 1080P, so no loss for me.

    - Walter.
     
  6. Sami Kallio

    Sami Kallio Screenwriter

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    Yes.
     
  7. Cees Alons

    Cees Alons Moderator
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    If you own a 1080i display the resulting picture of a 1080i source will be exactly the same as the picture of a 1080p source on a 1080p display.

    There is no difference: the picture is precisely the same, just transmitted in a different (internal) order.


    Cees
     
  8. Sam Davatchi

    Sam Davatchi Producer

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    Wow! I didn't know that! So what's the difference between these two? I can imagine 1080p sends its picture in one go but 1080i in two fields but the result of both is a progressive image. Is that correct?
     
  9. Cees Alons

    Cees Alons Moderator
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    The result is the full image. And it's the same image in both cases.


    'Interleaved' means: of the image the odd vertical lines are sent first (as a "half-image"), and then the even vertical lines. The image is then reconstructed, either physically (in memory in a monitor), or else physiologically (to the human eye by projecting the half-images one after another, as in a classic TV set).

    'Progressive' means: of the image all vertical lines are sent in the original order (generally taking twice as much time as the half-image of an interleaved communication does). The image is then reconstructed either physically (in an image- memory) or physiologically (to the human eye by sending it to a CRT, one line after another).

    In both cases (unless gross errors are made somewhere in the process), the resulting image is the same: the one that was transmitted (e.g. a film-frame).

    Problems may arise, when an interleaved image must be converted to a progressive image from a 3-2 pulled down source (and vice versa, but that doesn't arise in practice, because there are no 3-2 pulled-down progressive sources, as far as I know).

    Normally and typically, they don't however.



    When do problems arise?

    Only if the image was a 3-2 pulled-down source (bringing the film's 24 fps to an NTSC TV's 60 fps) and the source does no longer have the original information (about what half-image belongs to which whole film frame).

    One of the solutions then is "reconstructing", as some de-interlacers do, and the result is very acceptable.

    Another solution is called "bobbing": each half-image (intermittently the odd- and the even-halves) are filled by doubling the lines and then treated as a progressive image (at double speed). The result to the human eye is a slightly diminished vertical resolution (horizontal is the same), so it looks a bit softer than the original - but still very acceptable, according to many, and close to the proper interleaved or progressive version.



    Cees
     
  10. Sami Kallio

    Sami Kallio Screenwriter

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    Wouldn't that be true to 480i vs. 480p as well?
     
  11. Cees Alons

    Cees Alons Moderator
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    If done well: yes.

    Did you ever see a DVD and thought that it looked like 240 vertical lines?
    (Caused by the fact that it is interleaved, that is. [​IMG] )


    Cees
     
  12. Sami Kallio

    Sami Kallio Screenwriter

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    No, but 480p does look better in practice. I still have my 480i CRT FP setup in place and you can tell it's interlaced on a 116" projected picture. If it was 480p I would still use it for movies instead of its replacement which is a 720p LCD FP.
     
  13. Allan Jayne

    Allan Jayne Cinematographer

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    All the hi-def DVD players must be able to output 1080i since so many HDTV's accept only that. The players may or may not have selections to output in other format.

    The 1080i player output will deliver the best picture quality your 1080i TV can deliver.

    If the video ends up as 1080i whether recorded on the disk that way or formatted as 1080i by the player prior to output, and if the TV is 1080p or 720p, then picture quality degradation will result if the video is not converted back optimally.

    All SD DVD players initially decode the video as interlaced (480i) and also any output at a higher resolution format including 1080i has quality dependent on good 480i to 480p conversion.

    Today you can buy and hitch something (for as little as $1500 for a Lumagen HDP) behind any 1080p TV that accepts 1080p, and any 1080i program will come out on the screen close to what it would have been if it were 1080p in the first place.

    Video hints:
    http://members.aol.com/ajaynejr/viddoubl.htm
     

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