Which order? CRT/Video Processor Calibration

Discussion in 'Home Cinema Buying & Building' started by Jenz, Mar 27, 2001.

  1. Jenz

    Jenz
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    All,
    In light of the discussions in other threads regarding implementing Video Processors (in my case The Rock) into existing systems I have become a bit confused as to the process that should be used to introduce The Rock into my setup.

    Previously with my Barco I would calibrate Component directly from the DVD Player using Avia/VE.

    Then I would calibrate RGB via HTPC (after setting the Geforce 2 to the known Overlay Settings on avsforum). I would then adjust the Barco's settings so that the HTPC matched the DVD Player in the Barco Memory Banks.

    Now however I have a whole suite of settings that can be done within The Rock which seem to support/contradict the others.

    In simple terms what should the steps be for calibrating a complete system now? What is the order it should be done in?

    Kind Regards Neil.


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  2. Mr.D

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    Need to cal for the image chain so I'd say adjust the display to be correct for the source. (ie leave all the rock settings at neutral).

    If the rock has multiple inputs I'd cal for the most accurate source ( normally dvd) at the display end and then use the rock adjustments to equalise for any other sources relative to the dvd.
     
  3. Edgeyboy

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    Who distributes The Rock in the UK ?
     
  4. Boris Blank

    Boris Blank
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    The ROCK is supposed to be going up in price on 1st May to $4000! Puts it out of my range (if I don't buy one before then)
    Paul
     
  5. Jenz

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    Edgeboy,

    No one distributes The Rock in the UK at present.

    Paulb,

    That price is not confirmed, it has been suggested by AVS Forum Members. Personally I'm thinking it'll go to $4.5k or $4999...
     
  6. Boris Blank

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    Jenz,
    Blimey - Thats a big jump in price! To be fair, it is by all accounts a very good product. Its really bad timing for me, I don't have the dosh at the moment although in all honesty I rather think that the Cinematrix route would do me nicely (notice, I have given up on the Quadscan!)

    I looked into the Cinematrix in some depth last year but the (rumoured) problems it had put me off - wish I'd bought now! At around £900 for the player and the mod, its very good value if, like myself, you only route DVDs through your projector with the odd boxing match or something every now and again. I have a PS2 but I'm not sure that a ROCK would be a cost effective purchase just to make it look good (if I could afford it I would jump at it!).

    We'll see (next week I'll have changed my mind again!).

    Paul
     
  7. Mr.D

    Mr.D
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    I would worry that any huge errors at the display device would necessitate rather large corrections at the scaler in software using this approach. Speaking from experience in calibrating hi-res monitors for grading motion picture film you try to avoid having any settings on any of the devices in the image chain going to extremes: mainly because the farther you go the less accurate the tolerances become and this can have a knock on effect on the hardware.

    For example I'd hate to think the settings on the rock were driving the red tube to extremes to compensate for an inordinately high blue gain at the projector.(turning down the blue gun at display would be a better approach) Sort out the hardware accuracy then use software adjustments for tweaking individual sources.

    You don't want to get into a situation where you are correcting one characteristic "curve" with another "curve" on top when you could just set the first curve more correctly in the first place. Any adjustments in software on top are subsequently less extreme and less likely to stress the hardware.

    Think coarse and fine. Display Cal is coarse to get it in the ballpark) tweaks at the rock are finer to sweeten things up and equalise.
     
  8. Jenz

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    Mr.D,

    TAW's view is different:
    Ignore the American PR but this is an interesting approach. Its essentially saying that the Internal Calibration Tools of The Rock should be used for Rock -> Projector setup.

    Then any image issues would probably be a direct result of Source. I must admit to now being quite excited [​IMG]

    If anyone wants a demo in April [​IMG]



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  9. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Gotta say when I thoght about an answer to this I thought of Mr D's. I still suspect he's right.

    I'd set things up with Rock set at FLAT then set colour, brightness etc based on your most used source. Then, if the settings for other sources were wildly out, I'd set to a mid point for all or accept that you can only calibrate the optimum for one source and take the rest as a compromise

    All the best,

    GF

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  10. Oasis

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    I gotta say guys that I believe the TAW method is the right way to go.

    You've got to believe that the Rock has actually been set up correctly - i.e. gains of red green and blue being equal - so there is little chance of one channel driving the projector too hard.

    The thing we don't know about the Rock is where it's proc-amp controls (brightness, contrast etc...) are actually implemented i.e. whether they affect the input side or the output side.

    As the Rock has test patterns, the assumption would be that they are generated at full range of the output of the unit and that therefore you should set the projector up so that the test patterns are correct.
    You would then use the Rock proc-amp controls (assuming they don't affect the test patterns) to match the sources to the test patterns.

    If, however, the proc-amp controls do affect the test patterns and there are no input proc-amp controls then the test patterns are redundant for calibration set up, their only use then being to set up the geometry!

    If you use the Rock's controls to compensate for projector inaccuracies you are pretty much guaranteed to either a) run out of range or b) limit the bit depth of the processing chain. The controls on the Rock should be used to compensate for source inaccuracies.


    Still, only my opinion of course!

    Oasis

    [This message has been edited by Oasis (edited 29-03-2001).]
     
  11. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Thanks Oasis.

    I will bow to your superiour knowledge on this one then!

    Gordon

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  12. Mr.D

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    You've got to bear in mind IF the Rock is 100% accurate what is it accurate to? Does it state this anywhere in the documentation?

    You can only make a decision on the level of accuracy in your image path after you've seen it displayed.

    You then have to make a decision as to whether the source or display is accurate in the first place and adjust the other one relative to it.

    IF you can guarantee the patterns generated from the rock are correct and valid then it would be fine to calibrate the display relative to these patterns.

    However as Gordon says I'd advise keeping the rock at its defaults (or rather the defaults that are correct for your given situation) then calibrate the display device relative to this set-up then use the adjustments on the rock to equalise variations between different sources.

    This can ONLY be a good thing as you are ensuring the display and scaler aren't pulling in opposite directions.

    If the accuracy of the rock is questionable I'd still stick to my original scenario. Have the rock at default and use a dvd player (most are pretty accurate IME) as source through the scaler displaying VE or AVIA patterns as reference and use that as your baseline for display calibration. Then once again use the rock adjustments for other source equalisation.

    Even if The rock is 100% I'd still personally calibrate to the most important image path ie: the dvd player. This would ensure that any inaccuracies at the dvd player were also corrected for at the display. You are then effectively calibrating for the whole image path not just individual components.
     
  13. Oasis

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    Originally posted by Mr.D:

    However as Gordon says I'd advise keeping the rock at its defaults (or rather the defaults that are correct for your given situation) then calibrate the display device relative to this set-up then use the adjustments on the rock to equalise variations between different sources.

    Mr D,

    I think this means we are actually saying the same thing, albeit in different ways!

    The important thing is always to get the primary signal path correct - and if this means compromise elsewhere so be it, but I would maintain that the test patterns give a very useful tool to ensure that the system is optomised and matched throughout. If you do not have this feature you CANNOT reliably set up the controls on the projector, Rock or DVD player as all three sets of controls will be working against each other.

    The other thing involved here is colour space. I'm assuming that the input to the Rock is Y,Pr,Pb, Composite or S-Video and the output of the Rock to the projector is RGB. In this case the controls for the Output side have different effects to the input side as some examples; R, G and B controls (fundamentally colour balance) can only be set on the output side (i.e. the projector) whereas Saturation can only really be set in the YUV domain. Using the wrong controls for the colour space you are in will give distorted results which cannot be easily rectified later on. Built in test patterns give you the opportunity to identify and resolve those errors at source and not bodge it later on!

    Broadcast types usually have test pattern generators (often built into the equipment)and waveform monitors or vectorscopes (even in the digital domain) to make sure that the various controls through a chain specifically don't fight each other, so I think TAW;s inclusion of test patterns, while perhaps making the installation initially more confusing, actually makes it more accurate, repeatable and reliable.

    Anyway still only my very humble opinion!

    Oasis
     
  14. Jenz

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    Well at least it appears I'm going to have hours and hours of fun setting up [​IMG]
     

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