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Picture Size/Upscale Sanity Check

Discussion in 'Blu-ray & DVD Players & Recorders' started by richjthorpe, Feb 7, 2005.

  1. richjthorpe

    richjthorpe
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    Hi all,

    I was watching Star Wars 5 - Empire Strikes Bac at the weekend and also a bit of The Matrix (Showing off the new TV !) both of which are filmed in 2.35:1 ratio. This automatically sets my tv (32" Sharp LCD) to 16:9 aspect ratio.

    The native screen resolution is 1366x768 and I have a question about upscaling pictures......

    1366 is the width of the tv in pixels.

    1366 divided by 2.35 will give the height of the picture which is 581 lines.

    Since the DVD is encoded in normal PAL 576, could you say that the picture is near pixel for pixel matching ?

    And if so, would there be a need to upscale a picture format of 2.35:1 (Either comnputer DVD player) on a TV with my resolution ?

    Ofcourse for pictures with true 16:9 ratio or thereabouts upscaling will help, but 2.35:1 films wont need to be upscaled to 720p or 1080i as the max height (In 16:9 format) is 581 lines. I could obtain full screen by setting it to Cinema 16:9 but this chops off the edges.

    Am I correct in thinking this or am i completely way off ? Is this the correct forum to post this on ?

    Thanks,

    Richie.
     
  2. Thunder

    Thunder
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    Sort of. Dont forget the image on your TV is anamorphically enhanced and therefore not truly 2.35:1 when being displayed on your TV :)
     
  3. richjthorpe

    richjthorpe
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    Does it still get clipped on either side of the pictue with anamorphic ?
     
  4. Thunder

    Thunder
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    Anamorphic stretches the picture mainly in the vertical plain as far as I am aware (Im not sure as to the exact aspect ratio) A true 2.35:1 aspect ratio would be an old non anamorphic disc such as Titanic :)
     
  5. LV426

    LV426
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    I've tried to explain this before. I'll try again.

    Regardless of what shape films may be, there are only two exact intended shapes for video signals. These match exactly with the two available shapes for displays.

    They are 4x3 and 16x9. Your Star Wars DVD is a 16x9 DVD.

    Considering a 16x9 video signal, such as you might get from an anamorphic DVD.......The 576 lines are used to produce the full height of the VISIBLE image which includes the black bars seen on a 16x9 display. The black bars are encoded onto the disc, above and below the film, to create a video signal which is 16x9. They are a part of the video signal.

    Of these 576 lines, 432 (give or take) are used for the actual film image. The rest are plain black padding. They are part of the video signal.

    In other words, it would be strictly INaccurate to say your Star Wars DVD (and all the others like it) are 22x9 or 2.35:1 (or whatever) DVDs. More accurately, they are 16x9 DVDs containing 22x9 films.
     
  6. richjthorpe

    richjthorpe
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    Fully understand that, but the actual image (Not including the black bars) is a 2.35:1 picture that is 576 pixels high.

    As my LCD tv is 1366 pixels wide....1366/2.35 image means the height of the image (Excluding black bars) would be 581 pixels high. The tv is 768 pixels high meaning there will be top and bottom borders of 93/94 pixels deep.

    Would this be near enough 1:1 pixel mapping (I know there are 5 extra pixels) ? How would this compare to viewing a Hi Def image at 720 if I had a DVD player that sent 576p over DVI ? 720 upscale wouldn't do anything to the picture would it ?

    Richie.
     
  7. Strider123

    Strider123
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    Well that sorted that out!!!
    :)
     
  8. LV426

    LV426
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    No, it isn't. On an unscaled PAL TV signal, there are 576 horizontal lines used for picture IN TOTAL. The output from a DVD has 576 lines. Always. Exactly. INCLUDING any black padding put there to preserve the correct shape of the original image. On a 22x9 film around 432 lines have moving colour in them. Assuming it's all encoded right, there are 72 lines above, and 72 lines below, which are plain black.

    072 black
    432 coloured and moving (film)
    072 black
    ---
    576 total.
     
  9. richjthorpe

    richjthorpe
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    Sorry, you're right. I don't know why I put that the picture would be 576 high, ofcourse there are black bars !

    So the actual image I would be seeing is c432 high and that would be scaled up giving 576 pixels high on the LCD (432/576=0.75....0.75x768=576) ?

    So to top it off, it is worth getting an upscaler since what I though is incorrect as it is not a near 1:1 pixel match.

    Thanks Nigel/LV426.

    Richie.
     
  10. LV426

    LV426
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    The fact of the matter is that you already have a scaler/deinterlacer. It's inside your TV. All flat panel/pixel based displays, by necessity, have to have a scaler/de-interlacer to map the incoming interlaced line structure onto a pixel matrix.

    Buying a separate standalone device is a matter of how how much better than the onboard one it is. On that, I really can't comment.
     
  11. richjthorpe

    richjthorpe
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    Indeed. I can only summise that the recent crop of upscaling DVD players with Faroudja processing are better than the internal tv's scaler.

    I will have to wait a couple of months for that !! :D
     
  12. MickyGee

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    Richie,

    Bought a Cambridge Audio DVD 79. At 720p DVI on the Sharp PQ was very good, much better than RGB on my old Tosh - better contrast, dark detail and more natural colours. Even my friends with decent CRT's were impressed with the image. The improvement between 576P and 720P was significant.

    Comparing image size between RGB and 720P DVI, the digital image was very slightly larger, cropping a little of the sides and reducing the black bars top and bottom.

    Only problem is I am having lip synch issues (see dvd79 thread - seems to be an issue with this machine) so I am considering a refund and looking for something else. :thumbsdow

    Mick
     
  13. richjthorpe

    richjthorpe
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    Didn't realise Cambridge Audio did an upscaling DVD player ! Do you know which chips are inside it ? Also, does it upscale over component ?

    Thanks,

    Richie.
     
  14. MickyGee

    MickyGee
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    It has a Faroudja Genesis FL-2310 Scaler (720p & 1080i) however it only scales on DVI, and component isn't progressive.

    Had problems getting a picture on 1080i on the Sharp. Going back to Richer Sound tomorrow for refund.
     

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