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Does an HDTV improve DVD signals compared to normal TV?

Discussion in 'Televisions' started by living_forever, Jun 2, 2003.

  1. living_forever

    living_forever
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    Hi,
    I was just getting ready to buy a new TV for myself to mainly watch broadcasts and DVD's...There aren't any HDTV broadcasts in my locality so that's out of the question. But will a DVD take advantage of an HDTV. That is, do DVD's use 720p and 1080i?Another thing, do consoles(namely XBOX) post a problem with new RPTV? I don't know if this is even a question but it did say something like this in the manual...

    Thanks
     
  2. LV426

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    Can't speak for games, but for DVDs, the native resolution of the image is 704 * 576 (PAL) and 704 * 480 NTSC. Some DVD players can output progressive from on or both of these (ie. 480p and 576p).

    So the simple answer is 'no'.

    However, any high resolution device can (and in the case of fixed panel - DLP, Plasma, LCD - devices must) 'scale' the image to fit the greater resolution.

    Although scaling an image does not actually generate any more information (detail) what it does do, if done well, is subjectively increase detail by estimating what the additional lines might look like.

    This gives the impression of greater detail. The human eye/brain gets 'confused' by the structure of the image and sees the structure (pixels) rather than the image itself. Reducing the size of this structure (ie. by increasing resolution) reduces this effect and we are better able to interpret what we see.

    A couple of years ago, there was a link (on here, I think) to a website in which someone had used a high-end photo editing tool to increase the resolution of a low-res photo of some words on a sign. In its native state, it was illegible, but, having been rescaled, the words became readable. Rather than 'pixelled', they became, simply, blurred. And we can interpret blurred images better than pixellated ones. This was a powerful indication of the effect interpolated upscaling can have.
     
  3. living_forever

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    Thanks...that explains a lot. So, in effect the upscaling, like in PixelPlus, is somewhat like anti-aliasing on the PC. If DVD discs only come in native TV resolutions, not HDTV resolutions, is the difference between native and upscaled resolutions on large RPTV's really signifiacant?
     
  4. LV426

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    In the case of CRT based RPTVs the effect is significant in that the horizontal scan lines that make up the picture will be less clearly visible if they are more, and closer together. The larger the screen and/or the closer you are to it, the more this matters. In particular, users of CRT projectors (who are looking at large screens) often prefer to drive these, not from the native output from their DVD etc, but via external scalers that interpolate (and hence increase the 'subjective' reolution of) the source.

    In the case of LCD, DLP and Plasma devices then the image has to be scaled to fit, so the visibility of scanlines themselves isn't an issue; it is the visibility of the pixels in the panel that becomes the issue. For the same logical reason as described above, this is why more pixels are better on such devices.
     
  5. chiantiking

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    Not sure about the PS2 as I've not had a chance to use it, but Gamecube and XBOX games give warnings on projection TVs. To quote GC's label, 'Do not use with front or rear projection tv'. It goes on to say to contact the TV manufacturer for further info, and I think that's the best to do. Seems like some might be more likely to have burnin then others..?
     
  6. LV426

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    Here is an illustration of the effect scaling can have on an image.

    [​IMG]

    The image on the RIGHT is the original low resolution extract from a photgraph. The image on the LEFT is an upscaled version of the one on the right (actually 4x in each direction) ie - it was created entirely from the one on the right..

    So, although the one on the left actually has no more detail (it CANNOT have), which is more recognisable as a drawing of the US flag? Look especially at the 'stars'. And, on which one can you almost make out the words - given that it is an American flag, you should be able to work it out.
     
  7. NicolasB

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    It's more "filtering" than "anti-aliasing", but to some extent the two terms are equivalent.

    Depending on cheaper display you are comparing your HD display with, the ability to accept a progressive scan input may also be significant.
     
  8. Mora

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    God help me, i must have been reading this forum too much.


    Much of what you guys are saying is actually making sense to me :laugh:

    In theory then, you are much better buying a panel with more vertical resolution, upsizing, and then waiting for a scaler to come along that will give you what you want. rather than having say 480 lines of info and having to downscale the info so that you can see it.


    Steve
     

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