Toshibas displaying 540P. Why not just display native 480P??

Discussion in 'Archived Threads 2001-2004' started by JasonRH, Oct 23, 2001.

  1. JasonRH

    JasonRH Second Unit

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    It seems to me that upconverting progressive images to 540P would introduce artifacts in the picture. Why would the set not just display 480P and not do any conversion?
    Are all signals (including 480P) upconverted? Thanks.
    p.s I'm asking because I may buy a new toshiba soon.
     
  2. MichaelG

    MichaelG Second Unit

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    Does anyone have information on the specifications of how Toshiba upconverts the 480i/480p signals to 540p? I noticed that some of their DVD players also list 540 lines. Does that mean that the player is upconverting (which wouldn't make sense) the signal. I haven't heard anyone mention that the picture quality was anything but better than last years models, so I am interested in the algorithm for the conversion process. I am about to check out these TV's, but I doubt that they will have any side by side last years models.
     
  3. Marc Rochkind

    Marc Rochkind Second Unit

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    I don't think a DVD player with 540 HORIZONTAL lines of vertical resolution is possible, as NTSC DVDs have only 480 lines. Perhaps this figure is for the HORIZONTAL resolution. It's still high, as DVDs only have about 500 lines of horizontal resolution, but maybe it makes sense somehow.
    As to why a TV would upconvert to 540p, the answer is that that is half of 1080, which is the maximum a HDTV can display.
    As for artifacts, I don't know... maybe someone else can do the comparison for us.
     
  4. Jim A. Banville

    Jim A. Banville Supporting Actor

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    I may be totally wrong here, but I believe 480p and 580p are the same thing. The difference is one counts lines in the "blanking interval" and the other doesn't.
     
  5. MickeS

    MickeS Producer

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    I think 480p and 525p are the same thing, just different ways of counting lines, but that 480p and 540p are different scan rates. Since 540p is the same scanrate as 1080i, maybe Toshiba saved a few bucks by not showing 480p?
    /Mike
     
  6. JohnnyG

    JohnnyG Screenwriter

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    JasonRH, both 480i and 480p input is converted to 540p for display. The new models support only one scan rate for display (33.75KHz). Why? Most likely cost-cutting, but there was one major added benefit of a requiring only a single convergence/geometry memory.
    The upconversion seems to be quite good. I haven't heard anybody complain about it yet.
     
  7. JasonRH

    JasonRH Second Unit

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    Thanks for clearing that up, Johnny.
     
  8. MichaelG

    MichaelG Second Unit

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    I know why Toshiba does the 540p (same scan rate as 1080i), I was just curious if anyone knew the specifics about how they upconvert the signal. I did see a 50hx81 today at lunch, but only saw a satellite feed into it. There was a Pioneer (non-Elite) next to it and the picture looked fine (once I turned the sharpness down).
    I didn't think that the satellite picture was all that great, but I would like to see what it does with a 480i and 480p signal from a DVD player. Unfortunately I can't find anywhere in Houston that has the 57hx81 or 65hx81 (or the h series for that matter) on display. The store that had the 50hx81 wanted $2799 for it, no way.
     
  9. JohnHN

    JohnHN Stunt Coordinator

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    For what it's worth, I have a 50HX81 and have yet to see anything that looks like a scaling artifact, nor have I seen anyone claim, either here or at the Spot, that they have actually seen a scaling artifact. All the critism of the Toshiba's on this score has been speculative.
    What may be true, however, is that the 50HX81 seems to display somewhat less than the full available DVD resolution, as tested by the various charts on VE and Avia. Others have reported this as well. This noted, let me also say that I find the picture very pleasing. The main limit on resolution is the source: the picture is plenty sharp on the 5th Element superbit, somewhat soft on First Knight, for example.
    Perhaps JohnnyG could speak to this.
    The only real defect is that I have the infamous ringing/ghosting but that is visible only on certain material and seems to be present only on some of the sets.
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  10. JasonRH

    JasonRH Second Unit

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    John,
    Thanks for the added input. That helps.
     
  11. NickSo

    NickSo Producer

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    The toshiba upconverts video using its IDSC Pro Interpolation...
    It like stores the video into some memory, then it does something digitally and upconverts it... Its better than normal line doubling or DRC by sony.. here is a detailed readme of what Interpolation is: http://www.dtp-aus.com/interpol.htm
    It basically means it takes the two shown lines in interlaced video, and 'predicts' what will show in the line missing in...
    I also talked to an ISF Tech guy a couple days, he said it was a benefit to keep only one scan rate on the Toshiba, but i totally forgot why...
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    [Edited last by NickSo on October 23, 2001 at 06:53 PM]
     
  12. Jeff D.

    Jeff D. Supporting Actor

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    There is a reason Toshiba decided to upconvert all incoming signals (except 1080i) to 540p. It all has to do with timing. 540p has the same timing as 1080i. This allows the new Toshiba models to use one single convergence memory for all viewing modes. Convergence set-up is now much easier on the new models.
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  13. Michael St. Clair

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    Presumably the softness with a 480p input does not affect the HD input? If so, an HTPC DVD player outputting 540p may avoid the problem. Hopefully soon we'll have DVD players that scale natively to 540p/1080i and 720p.
     
  14. NickSo

    NickSo Producer

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  15. Jay Mitchosky

    Jay Mitchosky Producer

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    What Toshiba really needs to consider at this point is the release of a dual 480p/540p progressive player. One would think the rationale for scaling/deinterlacing in the player vs. the TV would apply at 540p as well. And since they have that technology for the TVs it shouldn't be too hard to plunk it into a future player. By my estimation this would offer the potential of a) improving the image on new 540p Toshiba TVs, and b) give folks like me a break with the previous 4:3 lineup and allow vertical compression on DVD sources. [​IMG] It's hard enough to differentiate players at these price points. This would allow some more ammunition. I know I would buy a 540p player in a hot second.
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  16. Massimo N

    Massimo N Stunt Coordinator

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    JOHNHN,
    you said:
    ----------------------------------
    the 50HX81 seems to display somewhat less than the full available DVD resolution, as tested by the various charts on VE and Avia.
    ----------------------------------
    Your set probably would beinifit from a calibration. After I calibrated my set (57HX81), (mechanical and electrical focus in particular), I'm able to resolve all lines on all the AVIA reolution (widescreen enhanced pattern, 100TLV and 200TLV)patterns, even the 6.75 pattern.
    I have not seen ill effects of the 540 scalling. I don't think I've read anyone with the set complain about the 540p. All negative comments appear have been people speculating.
     
  17. JohnnyG

    JohnnyG Screenwriter

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    Exactly what the TV is doing to upconvert to 540p is easy to see with the right test pattern. My Sencore pattern generator has a test patter called 'Focus' which makes it easy to see exactly which lines are being interpolated.
    I'm not so sure that a 540p DVD player or a HTPC set to 540p output would do a better job.
    The video scaler is likely interfering somewhat with reading the SMTPE Resolution Chart.
     
  18. Michael St. Clair

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    Johnny,
    Can you describe the line structure? Is it simply creating every 9th line as averaged from the line before and after? Or something else?
     
  19. Will

    Will Guest

     
  20. Michael St. Clair

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    quote: I wouldn't need a 540p player unless my TV couldn't display
    480p natively. Given the choice between displaying a DVD's
    native 480p output in 480p versus converting it to 540p,
    I'd go with the (native) 480p display.[/quote]
    We all think the same way. The issue is sets that do not display 480p natively, and sets that don't show anamorphic 480p in the correct aspect ratio.
    [Edited last by Michael St. Clair on October 24, 2001 at 12:57 PM]
     

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