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Discussion Starter · #1 ·
I know that Dilard 2.2 will have the new gamma wizard and is due out very soon. Unfortunately for me, though, I just got a used Dukane 9000 projector installed, and it has terrible gamma settings (at least that's what I'm assuming the problem is). Dark scenes such as many in Gladiator, for example, come out extremely low contrast. No detail can be seen in dark areas. Bright scenes look great!


I've tried adjusting the gamma settings in the HTPC I'm using, but this rapidly leads to posterization in darker scenes. I guess the projector just doesn't have enough low intensity shades of grey to accomodate the greater range the HTPC is outputting when you boost the intensity range of the low end.


Increasing brightness and contrast helps a bit, but you end up with color bleed and bright colors that end up becoming a single intense blob, losing their detail. Again, I'm assuming this is a problem that appropriate adjustments to the projector gamma table could fix.


Is there any manual way to tweak the D-ILA gamma table, so I could experiment with different gamma settings? Either via remote or via a program of some sort? Otherwise, I'll just wait for Dilard 2.2. I'm getting tired of making excuses why low light scenes look so horrible to the uninitiated when they view this otherwise nice projector... (I know, I'm whining, I'll stop now!)


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- Dan Butterfield
 

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Quote:
I'm getting tired of making excuses why low light scenes look so horrible to the uninitiated when they view this otherwise nice projector
You're not alone in this, Dan. I'm starting to think that the best strategy for digital projector (not just DILA) owners would be for us to march on Hollywood and insist that from now on they shoot all movie scenes in daylight.


Bob


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~ The Sultan of Cheap ~


[This message has been edited by RobertWood (edited 08-29-2001).]
 

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Discussion Starter · #3 ·
I'm curious technically how Dilard will be able to adjust any "gamma" type settings on the D-ILA projectors. I looked through the JVC RS-232 spec, and as far as I can tell it only describes overall brightness / contrast controls, as well as individual RBG gain controls. Nothing similar to a gamma table, though.


Will this be accomplished through some undocumented protocol?


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- Dan Butterfield
 

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Dan,


As I understand it, the protocols that are used by the

gamma table "wizards" of the D-ILA; Martin, Phelps,

Hunter,.... are not documented for the user - only for

the professionals.


You would have to get your hands on the professional

technician's documentation.


I assure you - the gamma table can be read and loaded

[ i.e. set ] via the RS-232 interface - that's how

DILARD works.


Greg
 

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Discussion Starter · #6 ·
It seems odd to me that JVC would publish a detailed RS-232 spec that is probably capable of rendering a projector unusable (if incorrectly used), but would not describe all the features of the protocol. I assume the motivation is more to reserve something that only the professionals can do, therefore justifying the existance of those professionals, than it is to protect end users from damaging their projectors or to save resources.


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- Dan Butterfield
 

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Dan,


They may also want to preclude you from getting enough

rope to hang yourself.


After all, a novice might mess up the gamma table pretty

bad - and then call JVC for a "warranty" call.


Greg

 

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Hi Dan,


With all due respect, those low-level D-ILA RS-232 codes are hidden because they are very powerful yet very dangerous.


Not only can you render the projector unwatchable, you can render it unwatchable in such a way that it is difficult or impossible to return to normal (complete loss of video sync, white wash, black out, etc.).


If all settings are not kept in-line and consistent, very bad things happen. I have been there more times than I care to count and have learned many lessons. One lesson is that it was wise to not publish the codes.


The Gamma could probably have been exposed somewhere, as touching it can make your picture look worse, but it won't (in general) totally ruin it.
 

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Mark's not kidding. If you don't have a complete backup of EVERY register value in your projector, you can really screw it up. And, it's not just a matter of knowing the rs232 codes - JVC did not use any checking in the rs232 protocol for these projectors. The gamma data is a rather long set of binary data, transmitted without any checksum or CRC. It is possible to have a comm error mid string and have the projector start interpreting the rest of the data as some other command. You can only imagine what a mess this can make.


Wm
 

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Discussion Starter · #10 ·
Well, I understand not wanting to give your customers enough rope to hang themselves (I've been in both the rope giving and getting end of that equation...). I just found it curious that JVC puts out a spec that seems detailed enough to contain enough hanging rope already, but left that part out. And, as Mark observes, probably the gamma table thing is one of the lesser harmful areas...


Just a curiosity, and I'm probably being a conspiracy theorist (he said looking over his shoulder) about something that is more likely a simple oversight.


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Kevin,


Thanks for the clarification.


JVC is typical - documentation is the last priority.


Of course, this is the pot calling the kettle black -

I'm no angel in that regard either - better than some.


Greg
 
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