Can someone explain to me why the HD-DVD players cant/dont convert 1080p to 720p ?

Discussion in 'Blu-ray & DVD Players & Recorders' started by Kopite4Ever, Aug 22, 2006.

  1. Kopite4Ever

    Kopite4Ever
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    Righty ive been doing some googling about this subject and i cant find a clear answer. Maybe its a simple answer but im taking a fair bit of info in and i could have just confused myself :D

    I realise the whole deal about 1080i > 540p > 720p and why its just "easier" to do that with a simple BOB as there isnt much processing power needed at all. In my opinion this is just not HD as your losing what 20% of the information :thumbsdow

    What ive noticed someone mention is the act of getting from 1080p to 720p is 1080p/24 native on all current releases of HD-DVD (bar the 2 1080i ones) to 1080i/60, converting that to 540p, then upconverting the 540p to 720p. Im sure there is a pretty good reason but im failing to see what it is.

    So why cant i go from straight 1080p to 720p without 4 stages of conversion ?

    Also will this ever change, if my display scales 1080i to 540p then up to 720p & so does the player, in theory i will never get to see proper HD untill i get a display that is native 1920x1080 wether it accepts 1080i or p and at the moment i enjoy my AV gear i dont want to upgrade as of yet.

    So any words of enlightenment from those alot more knowledgeable, oh and please dont say get a proper scaler like a lumagen, im skint enough as it is :devil:

    Im really on the verge of jumping into HD-DVD as ive seen alot of HDTV stuff via my PC :oops: and its quality stuff. I dont want to jump in a feel cheated that im only ever going to see a 540p signal scaled to my display's res.

    Regards
     
  2. gavan

    gavan
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    Most kit out there can't handle 1080p - so the player has to convert this to 1080i at it's output.

    When you feed the interlaced 1080i output to a panel, chances are that the panel takes the easy way out and treats the 1080i signal as a 540p signal. It's the easiest way to 'deinterlace' to prog scan.

    The panel will then upscale that 540p to 720p (or 768p) in order to display it on the actual LCD screen.

    A panel with good deinterlacing will do a more sophisticated job but it's been said that most of the panels out there do it the 540p way.


    There's no reason why a _player_ couldn't scale and deinterlace in a more direct manner to 720p but apparently the current Toshiba HD-DVD players have some sort of defect in their chipsets that leads to substandard 720p output. Hence people are choosing 1080i on the player side and letting the screen or an external deinterlacer do the job.


    Once 720p res panels can handle 1080p input it'll be a moot point. Of course, by that time the market will likely have moved on to 1080i/p panels anyway.

    Gav
     
  3. Kopite4Ever

    Kopite4Ever
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    I got all that and understand why it does it.
    In bold is what i was getting at and wondered why there isnt a more direct route. Is it likely the 2nd generation of players will rectify this ? Id love to be able to afford an external sclaer to do all my inputs but at this present moment in time i couldnt justify one.
     
  4. brandondanger

    brandondanger
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    so is this why my 540 res sharp p50 looks so good with hidef? it just rescales to half the original content?
     
  5. gavan

    gavan
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    People often forget that it's not just about extra horzontal lines, HD also delivers about 3x the vertical lines too.

    I'd guess that those sharps have a greater than 704 vertical line resolution, so they'll look quite a bit better with HD sources.


    Actually, I think that Sharp got it right going for a 540 line panel. By all accounts they look great on SD and show a noticeable improvement with HD.

    Contrast this with 768 panels. They have to scale SD up and still have to scale HD down, and not even with a nice easy 'divide by two' sort of scale like the Sharp has.


    Gav
     

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