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HDMI and 1080i (jeff help)

Discussion in 'Projectors, Screens & Video Processors' started by gandley, Aug 6, 2005.

  1. gandley

    gandley
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    Ok im not having any problems but just want to clarify this thought.

    The HDMI input of the sim2 can not except a 480i/576i signal because the HDMI input of the PJ requires a prog scan signal.
    So how the heck then does it display 1080i. is the 1080i signal sent out as progressive from the dvd player as 540p, which in turn if my display was native 1080i would be converted back to 1080i. so does the sim2 see it as a progressive signal at the lower resolution of 540p then upconvert it to 720p.?? or what??

    :confused:
     
  2. gandley

    gandley
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    ANYONE then as this does baffle me a bit as i am of the opinion 1080i will be deinterlaced first before its sent out the dvd player?
     
  3. Nic Rhodes

    Nic Rhodes
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    my money would be on 540p as t is for most of these devices :(
     
  4. gandley

    gandley
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    So it does not send out a pure 1080i signal, hence why perhaps you can send 1080i over DVI which is very much limited to progressive. so 1080is 2 interlaced fields are sent out as one progressive field and if the display was a native 1080i it would be converted back to 1080i to display natively.

    Its seems darn hard to actually find any concrete info on this, but thanks Nic
     
  5. Nic Rhodes

    Nic Rhodes
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    Tag explained it well several years ago on their forum but basically that is my understanding. Personally I think 720p has MUCH to offer as it removes many of the issues dealing with 1080i, particularly on deinterlacing. Most 1080i deinterlacing is rubbish, hence I prefer 720p, re actual resolutions there is little in it. 1080i deinterlacing just adds another complication and few can do this motion adaptive.
     
  6. Liam @ Prog AV

    Liam @ Prog AV
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    I would've thought a 1080i source would surprisingly enough send a 1080i signal!! And this doesn't need any deinterlacing before leaving the player as it is deinterlaced already on the disc. The player just needs to upscale the 480i/576i frames to 1080i frames.

    If the Domino doesn't accept interlaced SD resolution signals it is out of choice, not because the the standard does not allow for interlaced video. A 1080i source will still send 1080i, the Domino will receive it and use it's own methods (rightly or wrongly) to scale and deinterlace it back down to 1280x720 or whatever the native resolution is.

    But yes, 1080i is often deinterlaced so badly 720p can look quite better on all but the slowest moving scenes. Unless you stick a Lumagen in the chain :D ....
     
  7. gandley

    gandley
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    i see your point Liam but then how could you send a 1080i signal over DVI as it will only except a progressive signal? not saying anyones wrong its just many say 1080i is deinterlaced first, others say its not but i havent found a site that says, this is how 1080i is done.
     
  8. Nic Rhodes

    Nic Rhodes
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    More general info really....



    1080i is an interlaced signal and only fits into HDMI spec. The DVI spec is all progressive. There are a few DVI inputs that do recognise interlaced signals like Lumagen and KD but this is not part of the spec or the norm. It is to be encouraged however.

    The 1080i signal leaves players (scaled from 480i / 576i?) but interlaced. The receiving device then needs to deinterlace it and scale it. The later is generally more sucessful than the former. Deinterlacing on 1080i is currently largely NOT motion adaptive. Signals are converted to 540p and bob and weaved if we are lucky. These are the same techniques we were so critical of for DVD resolutions years ago and the reason why more accurate solutions like SIL504 and Faroudja are 'prefered' solutions. Once you get past the resolution and colour thing you will soon find you are back to worrying about poor deinterlacing.

    I have high hopes for the new Lumagen which may offer a step change in this area soon (along with the 11 point IRE tracking anf Genlock). The firm to watch :)
     
  9. gandley

    gandley
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    aaahhhh good stuff Nic
     

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