High Def Question

Discussion in 'Displays' started by Scott W., Sep 18, 2004.

  1. Scott W.

    Scott W. Second Unit

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    A 16X9 tv has anamorphic enhancement (better resolution) on selected dvds these days, and you abviously get better picture. What do these HD tv sets add to an already great anamorphic picture on a hd tv set? Besides watching tv programs in HD, what does a HD set do for an anamorphic dvd, enhance it even further? or nothing at all...? a responce would be appreciated. TIA.

    Scott
     
  2. Ike

    Ike Screenwriter

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    HD sets allow for progressive scan, which yields a crisper picture. You can also get players that upscale to hi-def, though it is just an upconvert. I have one, and find DVDs in 1080i are a little more pleasing than at 480p.
     
  3. Jack Briggs

    Jack Briggs Executive Producer

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    Please ask this sort of question here in Display Devices.

    No monitor/TV has "anamorphic enhancement." Widescreen sets are in 16:9, and, thus, are ideally suited to display DVDs that are encoded in a 16:9 aspect ratio. In addition, ATSC-based sets, as Ike notes, offer 480p resolution, which means you see all 480 lines refreshed simultaneously, unlike with interlaced output.

    Since DVDs are 480i natively, you cannot "add" resolution — even though you may view them either in 480p or 1080i mode. At 1080i, they won't necessarily look better, given that there are only 480 lines to resolve.

    What you want to see is whatever high-def optical-disc format comes along (Blu-ray or HD-DVD — neither of which are on the market in the U.S. as of now).
     
  4. Roger_R

    Roger_R Second Unit

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    I've found that playing back a DVD in a higher resolution makes the image softer. I particularly notice it when there's, for example, a black line that's exactly one pixel wide and there's white over and under it. When you upscale the image, that one pixel will have turned into 3 or 4 pixels where most of them are grey. It makes the whole thing look soft and out of focus.
     
  5. Allan Jayne

    Allan Jayne Cinematographer

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    The most common scaling done in an HDTV set is converting 480p to fields of 540 scan lines each. One method of doing that conversion is to double one line out of every eight. This way single black scan lines will remain single black scan lines for the most part. A few of the single black scan lines become double black scan lines.

    This makes diagonals a bit more jagged than one might otherwise think. To smoothe the diagonals, some additional blending is done making single black scan lines (on a white background) into triple gray scan lines, etc.

    I would expect that good scaling will still have the center of the triple gray scan lines really dark gray and the scan lines just above and below almost white. Alternatively just two scan lines would be dark dark gray and dark gray respectively while the neighbors are all pure white.

    Poor de-interlacing (such as exclusive interpolation), or going directly from 480i to 1080i without 480p as an intermediate step, can cause the problem you describe.

    Also, if the HDTV does not have a 540p/1080i option, or if 1080i is selected from that option, single scan lines in the source show up as two on the screen, double scan lines show up as four, etc. If the scan lines are fat enough, you may not notice this.

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

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