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Quadscan Elite...

Discussion in 'Projectors, Screens & Video Processors' started by Paul D, Sep 30, 2001.

  1. Paul D

    Paul D
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    I was wondering about scaling and line doubling/tripling/quading.<br />Is line "quading" the same as scaling?.<br />Ie would the elite running at say 1024x768 be same as line doubling/tripling/quading.<br />Or do line quaders just up scale one way ie horizontal/vertical resolution etc.<br />What would give the best results for CRT quading or scaling.<br />I know i'm not being very clear but i have not got the hang of this side of things!.
     
  2. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Paul: Scaling is just outputing a different resolution from what goes in. So quadrupling, is a scaled output. It's 720 X 960 I think, off the top of my head.Tripling is 720 x 720 with a Quadscan. That's given a NTSC input signal.

    So you can see 1024 x 768 (xga) is an in betweeny sort of ratio. There are those who say that direct multiple' sof the incoming signal give best results. I'm not sure of this yet.

    Now, just to confuse a wee bit more....There are scalers, and Vigatec is one of them, that have 720P and line Tripled as output resolutions...So, if NTSC tripled is 720P what is their 720P resolution? Well, it's 1280 x 720 with timings as Specified by ATSC for HiDef TV playback in the US. It mimics a HDTV720P resolution.

    CRT devices are cool. They can do all sorts of weird resolutions as long as it's within their bandwidth and scan frequencies. Nic has been talking about this recently.

    For CRT what you want is to get each scan line as close together as possible without them overlapping. (that's the vertical resolution bit) then you want to get as much horizontal resolution as is possible without the bandwidth limitations of the unit making the picture soft. Preferably at refresh rates which reduce motion artifacts. That's my take on the matter anyway.

    Problems occur with CRT in that ideal vertical resolution for getting scan lines touching is different from unit to unit and dependant on age and set up. At ISF training they were using a Runco992 Ultra (Barco Cine8 in disguise) It was being run at NTSC tripled (720 horizintal ines across the screen). Standing 1 foot away you could see scan line structure. This was on a 16:9 screen. It was set up immensly well. The guy who did it figured it needed a 840P signal. Now, try finding an off the shelf scaler with that output resolution.....I can only think of one...just now.

    Oh my god! reading back through this is a mine field and a can of worms...and that sounds dangerous...

    See you guys later.

    Gordon
     
  3. Paul D

    Paul D
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    Gordon. Thanks for the swift reply!<br />What i had been lead to believe is line doub/trip/quads scale only.<br />Where as scalers (quadscan etc) also de-interlace + 3-2 pulldown.<br />So if the quadscan was set to "Line Quadrupling" instead of say 720x960(or what ever res) would it still de-interlace + 3-2 pulldown. Or is doub/trip/quad just a easier way of saying 480p-720p-960p etc, still doing de-inter + 3-2?.

    I'm not going to start getting "Anul" about figures, as i'm sure you will set me up correctly with the Quadscan.<br />It just nice to have some basic idea where next months mortgage moneys going!.
     
  4. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    All scalers I know of will de-interlace the image first, if it isn't progressive already, then dol the scaling.

    They may use 2:3 pulldown recognition to re-constitute teh original film frames or they may not. Depends on the processor in question. For instance, I don' think the Terranex has 2:3 recognition...yet by all accounts it does film based DVD de-inter;acing quite well.

    The Quadscan Elite has auto sensing to work out what sort of processing to use.

    Gordon
     
  5. ReTrO

    ReTrO
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    fulabeer: If the signal is being quadrupled I think it is first being de-interlaced (which doubles it) and then somehow doubles the lines again, whether by inpertpolation (guessing the inbetween lines since they don't actually exhist, as it were) or just doubling up the other lines.

    For scaling is kinda multiplies the input signal by the appropriate ratio to give your desired output signal. But rather then just doing this to the vertical resolution (as with doubling tripling etc. where it is still 720xXXXp), it also multiplies the horizontal resolution so you will get, using Gordon's example, 1280x720p (tripling will just give 720x720p).

    Scaling will give square dots/pixels, whereas doubling etc. can give different shapes depending of the vertical resolution.

    Hope this is correct, chat tonight!

    If you get one enjoy it, I hopefully will have one myself for 'testing' for work at home...
     
  6. RichardA

    RichardA
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    Theoretically at least a Line doubler/tripler/quad repeats the number of lines that many times - it does not generate additional information, it simply repeats whats there. This will help to fill in the gaps between CRT scan line but that's it.

    A scaler will take the incoming information and use it to interpolate in between information to fill in the gaps - this should provide a smoother image with better apparent resolution. Most scalers operate in the progressive scan domain so will have a de-interlacer first and then a scaler. Certain scalers can then output interlace again if needed.

    The generic terms used have been applied with alternate meanings - the vigatec line tripling for example is actually scaling (i.e. lines are not physically repeated - they are interpolated, but within the timing profile of tripling)- so you can't be completely sure that what I've explained is true in all cases!

    It is also true that many advocate scalers to be set to do clean multiples of pixels or lines - this is only appropriate if the interpolation algorithms are not as good as they could be and therefore varies between scalers. As I hope anyone who went to the 'Event' saw - all scalers are not created equal!

    I hope this helps!

    Richard Ansell<br />Snell & Wilcox

    (I have a nasty feeling a lesson on interpolation may be requested soon!!!)
     
  7. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Richard: Glad you're back. Did you see my question about V.E.'s new disc. Have you seen it? Is it good?

    Gordon
     
  8. Paul D

    Paul D
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    Top class answers guys! <img src="biggrin.gif" border="0">

    I feel i'm grasping the fundamentals.

    Now if i can just find a "Interpolater Gold" for about £1500 i will be fine!.

    Richard, is there any factory returns in the region of £1500.(i don't mind if it doesn't have SDI etc) No? well i had to ask!. <img src="graemlins/evil.gif" border="0" alt="[Evil]" />

    Gordon, get a Quadscan Elite warmed up!. <img src="wink.gif" border="0">
     
  9. Jimmy the Saint

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    fulabeer<br />I already have a system comprising of an 808 and an elite. If you need any help, or a demo of this combo, please free to e-mail me and I will oblige. <img src="smile.gif" border="0">
     
  10. RichardA

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    Gordon - sorry I haven't seen your post on VE2 & I don't think search is working. Can you post the thread address please!

    I have seen a prototype of some of what I believe was VE2 and there are a lot more (S&W created) test patterns including Test Card M which has been designed specifically for MPEG testing. Next time I'm in the office I'll have a word with the relevent parties to find out what we know on this

    Fulabeer - For some unknown reason we find it difficult to get even demo units back, let alone returns - I guess people like them!!! The only unit I am aware of is the one that was on the classifieds which was about £19000 - it's only one extra zero on your target price, I'm sure the plastic can take the heat!

    Richard.
     
  11. Paul D

    Paul D
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    Richard.<br />The only thing i will be spending £19,000 on, will be on a "used" Audi TT after Christmas! <img src="biggrin.gif" border="0">
     
  12. Edgeyboy

    Edgeyboy
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    For £19,000 you would be better off with the Snell & Wilcox mate!

    The TT is all form and no function...
     
  13. Jeff

    Jeff
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    the TT is class as is my own Audi coupe.

    Jeff
     
  14. Edgeyboy

    Edgeyboy
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    We has a 230bhp TT and it had a gear box from that resembled a wooden spoon in a cardboard box.<br />Sold it and bought a BMW 330ci. Much better.
     
  15. ReTrO

    ReTrO
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