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Can anything out there Display 1080i?

Discussion in 'TVs' started by webbp, Mar 1, 2004.

  1. webbp

    webbp
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    Euro 1080 transmits in 1080i
    From what I can gather most other US stations do aswell.
    A lot of the news content we have discussed comes in full 1080 line format too.
    However, even the biggest plasmas seem to be 768 lines.
    The new Sharp 45inch LCD will support 1080p.

    My question is: Is there any screen out there today, that can display a full 1080i picture thats not a PC?
     
  2. Messiah

    Messiah
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    Hmm. Isn't 1080i actually 540p therefore capable of being displayed on XXX x 720p display devices?

    Don't shout at me, I'm just guessing :)
     
  3. webbp

    webbp
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    Nah, if I read it correctly. 1080i is similar to any normal television where the frame is interlaced. ie alternate lines are sent in two different frames.
    But there are 1080 lines as opposed to 576 in normal PAL broadcast (which are sent in two frames of 283 lines).
     
  4. KraGorn

    KraGorn
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    Well that's what my Z200E displays when I feed in 1080i, it says it's getting 540p. :confused:
     
  5. webbp

    webbp
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    Oops, didn't know I was gonna cause heartache dude :blush:
    My apologies.

    A quote from the net:
    Format Description
    480i Digital version of current television signals.
    480p Also known as "standard definition" - has the same detail as today's television signal but looks sharper
    720p The HDTV format used by ABC and probably Fox. This format provides an image just about as good as 1080i, while allowing other 480p signals to be broadcast at the same time.
    1080i The most detailed image available from broadcast TV - the HDTV format used by NBC and CBS.

    The number refers to the number of lines of vertical resolution . Generally the higher the number, the better the picture. For example A 720p image is much more detailed than a 480p image.

    The letter refers to the way the TV makes the picture, either Progressive (p) or Interlaced (i).

    A progressive scan means the TV draws line 1 of the image, then draws line 2, then line 3, then line 4, etc. until it reaches the bottom of the screen. Then it starts on the next image. This is what your computer monitor is doing right now.

    An interlaced scan means the TV draws line 1 of the image, then draws line 3, then line 5, and every odd numbered line from there. Then it comes back and draws every even numbered line. This is the way regular TVs work.

    You may have noticed that the image on your computer looks better than the image on your TV. With today's technology a progressive scan looks sharper than an interlaced scan. So a 480p image will look sharper than a 480i image.

    Because a 'p' image looks sharper than an 'i' image, we can reduce the number of lines of resolution and still get a good-looking image. So a 720p image looks almost as good as a 1080i image.

    Hope this helps a bit
     
  6. richard plumb

    richard plumb
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    Messiah, I'd say no.

    technically you are displaying the same amount of information per 1/60 second - i.e. 540 lines. But with 540p you are displaying a 540 line image 60 times per second. Thats how much detail is in the image.

    With 1080i, the image contains 1080 discrete lines of detail, but it is built up in two passes. It relies on persistance of vision to show the full image. Surely if it displays as 540p, the 'old' field is being replaced with the new one, so that persistance is not able to build up the full detail possible in 1080 lines.

    And of course, 1080i lends itself to 1080p movies...
     
  7. hornydragon

    hornydragon
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    I think Fujitsu ALIS screens can handle 1080i but the better the picture sent the better the picture displayed.
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    It's a 1920x1080i signal.

    So perhaps a 1920x1080 pixel device might be more appropriate.

    There are many devices that can display an image from a 1080i source but there are not many that can actually display its full resolution
     
  9. ReTrO

    ReTrO
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    At the 'basic' end you could look at a 32" or 36" JVC CRT widescreen set, cost you around the £1k mark. I think it's their top DIST models.
     
  10. Muf

    Muf
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    I would have to agree with Messiah.
    Nothing like a good old argument, just joking.
    1080i 30 frames per second consists of 60 fields per second, each field is 1920 x 540 pixels. Each of the 60 fields are 1/60th of a second apart ie. you cannot combine each pair of fields to reconstruct a 1920 x 1080 frame, it would be jaged where there is a lot of motion. So it is a bit like 540p but a bit more horizontal resolution and double the frame rate.This is why interlaced is great for sport events, very little judder when the camera pans quickly.
    If a 1920 x 1080 DLP became available tomorrow and I rushed out with my checkbook, on ariving home I would only see a 33% increase in resolution (all in the horizontal axis) over my 1280 x 720 DLP even though I would have more than doubled the pixel count what a bummer. If I had 1080p material to look at, that would be a different story.
    Here is a simple experiment to illustrate.
    Capture some footage from Euro1080.
    Play it back in WinDVD or other
    Do a 'Bookmark/Capture' > Capture Image
    Save it as a jpeg and examine it.
    You will have a 1920 x 1080 (1088) image but only the top half is picture ie.1920 x 540, the bottom half is a blank green area.

    Jim
     
  11. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Ah...but when there is no motion there is double the perceived resolution.

    Also what heppens if your 1080i material may have been derived from a progressive source such as a Film frame. In that case your 1920x1080P dlp would hopefully be able to reconstruct the original1920X1080P frame and display it. This would have double the vertical resolution of a 540P signal.

    Gordon
     
  12. Muf

    Muf
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    True enough Gordon, 1080p or indeed 1080p broadcast in 1080i format is a different story. I am eagerly anticipating that problem

    Jim.
     
  13. webbp

    webbp
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    Ok boys, Chill ;)

    Now that we kinda are on the same page.
    Is there anything out currently that can display the full 1920x1080 resolution?

    I dont mean accept the signal.
    I mean actually display it.
     
  14. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    yes Some hi-res Dila projectors from JVC, Sony's new Qalia SXRD display and well set up 9" CRT projectors. There are no direct view CRT displays that I know of that can actually resolve the full resolution of that signal.

    There might also be D-Cinema DLP's but I can't remember the res of the top TI chips.

    Gordon
     
  15. Rimmer

    Rimmer
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    Correct me if I'm wrong, but I believe 1080i is not really 1080i!

    I don't know if this also applies to Euro1080, but due to bandwidth limitations 1080i is filtered down to 1440 horizontal pixels for broadcast in the US/Australia. Therefore the actual resolution is 1440 x 540. In addition, the Sony HDW-F900 HDCam, with a purported resolution of 1920 x 1080, actually captures only 1440 horizontal pixels and interpolates up to 1920. I think this is due to data storage issues.

    When broadcasting low frame rate progressive material e.g. movies 1080i should still look better than 720p, provided it isn't filtered for its vertical detail. A 720p/50/60 recording should look better than a native 1080i/50/60 recording due to better motion capture and the absence of artifacts - at least in theory.
     
  16. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    You are wrong....but possibly right

    The spec is for 1920x1080 and that is what is broadcast. However what the resolution of the content is may be different. It might be 1440x540m per field but that issues with fields and frames has been covered above already.

    Gordon
     
  17. Muf

    Muf
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    Thanks Rimmer,
    Interesting information. I had noticed also that some of the WMVHD 1080 clips are 1440 x 1080 when you inquire the file properties.
    I have done a number of tests as described above (JPEG frame captures at the full resolution) on the Euro 1080 transmissions and making comparisons with my 720p image. Always curious about how much I am missing and really I don't see a big difference. For instance, small details in a frame, I wonder if it would be clearer in full res so I do a JPEG capture, blow it up in photo shop and there is nothing more in it. To be fair I don't know enough about the whole process to make a reasonable criticism but I suspect that the codec could be the weakest link in the chain. Perhaps the signal quality really is 1920 horiz pixels but the decoder cant resolve it in which case it wont matter how many pixels you have in your display beyond a certain limit. A test card with an area of fine vertical lines would be a good test. There were some test cards transmitted before the Super Bowl, I must have a look and see if I saved any of that.
    Still the quality is fantastic when compared to SD, especially that new Astra HD test transmission and lots of credit to Euro 1080 for kick starting the whole thing.
    Sorry Webbp I am of no help to you in deciding which display to get.

    Jim
     
  18. webbp

    webbp
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    No worries muf. I welcome all info. So big thanks to all.
    I think I'll wait for the new Sharp LCD as it says it can do 1080p

    Besides, not that much content around currently.
    Be interesting to find out what that Astra test is leading to though.
     
  19. Rimmer

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    Gordon, I wasn't implying the broadcast signal itself has anything other than 1920 horizontal pixels - obviously it has to have that to fit the HDTV 1080i spec.

    Muf, as I understand it the signal is filtered down because hardly anyone has a 1080p display anyway, and because a 1440 pixels interpolated up to 1920 has fewer MPEG-2 compression artifacts. I surprised the WM9 clips are filtered though - maybe they were encoded from 1440 x 1080 masters?
     

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