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What utility (DVD) to calibrate projector?

Discussion in 'Projectors, Screens & Video Processors' started by Tempest, Feb 22, 2005.

  1. Tempest

    Tempest
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    Must say I'm a tad confused about calibrating a projector.

    I've got a Pannie AE200 (but I shall use any info suggested for any future machines!)

    Here's my confusion.

    On the AE200 (and I assume other pannie's) you have a NORMAL mode and a DYNAMIC mode. (plus a few others)

    The problem is. I bought the Avia DVD and have run through it, actually finding the default pannie settings were pretty much dead on + or - a few notches.

    But, It can be Perfect on Normal, and also perfect on Dynamic.

    But when you actually play a DVD movie, the difference between the two modes is enormous, which in my mind makes Avia pretty useless really.

    I actually use a few scenes in a couple of DVD's at the moment to judge if detail is washed out.

    I'm wondering, as I'm driving the projector from a PC, if you could use like some testcard images from the computer to set the thing up.

    Or would there be some other calibration DVD's that you can use?
     
  2. Gary Lightfoot

    Gary Lightfoot
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    These may be different colour settings that don't necessarily effect contrast and brightness. I take it you used the needle pulse tests (title 1 chapter 1)to set the white and black levels? The darker of the two black bars should just be visible, as should the brighter of the two white moving bars. Setting one can alter the other so check them both as you go.

    Using a PC can give some odd results - PCs use a colour range of 0 to 255 which are digital levels (as stored on a DVD), but a DVD will have digital 16 as black, and 235 as white, which are video levels. If you use a software player, it should also use these levels (sometimes called sRGB) on the overlay so that it displays correctly, and you can still set your black and white levels in the same way as a standalone player. Either Avia or DVE is fine, as the PC doesn't output a tv transmission standard, just a progressive image, so you don't have to worry about black levels being different. Having said that, I've not tried comparing both PAL and NTSC on the HTPC, so now that I've mentioned it, I'll have to go and try it. :)

    On a standalone player, Avia will set the black level according to how the player interprets it - as Avia is an NTSC disk, the player will send out an analogue signal of 0.53mv for digital 16 (black) which is often called 7.5 ire. That's normal for a DVD player that has a 'setup' pedestal for North American NTSC. If the player has the facility to convert the output to PAL (PAL 60 is not uncommon), then it will translate digital 16 as black at PAL levels, which is 0mv. If you use the PAL edition of DVE, the player will automaticaly send out black as 0mv.

    As you can see, black levels will be different for PAL and NTSC. Your projector may or may not remember these individualy depending on how many memories it has on its inputs. If it doesn't, what is black for NTSC is only dark grey for PAL. Anything below 0.53mv on PAL will be shadow detail until 0mv is reached. If you've set-up for NTSC, all that shadow detail belowe 0.53mv will be black, so you'll be 'crushing black'.

    Some DVD players have a black setting or 0ire setting under the NTSC menu (Pioneer for example), so setting that to 0ire will mean that both PAL and NTSC will have the same black level output of 0mv or 0ire.

    Getting back to the colour side of things - if you use Avia to display the ramped ire fields (title 1, chapter 7), you will see 11 bars going from black through grey to white. The greys should all be grey. Change the setting from Dynamic to Normal and see if there is any colour change. For D65 you should have a good grey set of bars, with no green or blue tints for example. Quite often the brighter bars will appear green or blue, and the darker bars may appear reddish or purple. This type of colour balancing is difficult to get exactly right to D65 without a colorimiter to measure the balance of the RGBs. UHP projector lamps are usualy red deficient, so that is often why some projector images look greenish. Reducing the green and blue contrast levels to match the red reduces the overall contrast.

    It's also possible that those settings may have different gamma settings so the overall luminence will be different for either setting.

    If it were possible to adjust those different colour settings to D65 using a colorimiter, it's very possible that they would both come out looking the same - provided the gamma was the same of course.

    There is a blue bars test for checking colour saturation. With the blue bars test pattern, you will see some flashing boxes. Looking through the blue gel, adjust the saturation until the flashing boxes appear to have blended in with the bar that they are in. A better explanation is on the disk.

    Does that help at all?

    Gary.
     
  3. Tempest

    Tempest
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    Thanks Gary for the excellent posting.
    I shall run through all you say and see what I find.
    Much appreciated.
     
  4. Gary Lightfoot

    Gary Lightfoot
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    Let me know how you get on. I'll be interested in the results.

    Gary,
     
  5. PjPip

    PjPip
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    Wow, excellent post there Gary!

    I've spent some time tweaking my latest setup as the "below black" bars on the DVE test card never show up. I think it's the DVD player (Pio 2750) as they used to be visible on my old Sony. I think I've probably got an optimum setting anyway, but you know how things bug you when they're not "just right" - new player coming methinks ;)

    Anyway, I was interested to read your bit about the PAL/NTSC black settings on the player as I don't think I have them (will check later - I guess it could be auto set by the PAL/NTSC/AUTO option?) but the PJ does (Epson TW10H). However, I couldn't get any noticeable change out of DVE when switching the PJ setting?? Perhaps I wasn't looking for the right thing.
     
  6. Gary Lightfoot

    Gary Lightfoot
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    If the player is multi-region (I guess it is), then it will be outputting PAL DVDs as PAL (0ire for black) and NTSC as NTSC (7.5ire). If you can make it send out NTSC as PAL, or vice versa, then you should only need one test disk to set black. If the player has the NTSC option of 0ire for black like some Pioneer models do, then both PAL and NTSC will send out black as 0ire.

    The PAL/NTSC/Auto option may be a way of ensuring the output is kept as a single standard such as PAL, and again, a single test disk should be fine. Otherwise you'll ideally need both a PAL and NTSC disk to set the levels.

    My H77 doesn't distinguish between PAL and NTSC on the component inputs, so if I set it up for PAL, the black level is wrong for NTSC, and vice versa. My HT1000 on the other hand recognised the different signals and adjusted accordingly IIRC.

    You can tell if the settings are wrong by using a PAL test disk to set the levels and then check the same levels on an NTSC disk. The THX Optimode is designed for the disk it's on rather than a blanket test disk like DVE or Avia, but you might be able to use that to see if the levels remain correct between the two standards.

    Gary.
     

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