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JVC gamma table upload

 
Author ulrichd
ZRO
#1 | Posted: 13 Aug 2019 23:01 
While looking into how to get the LightSpace exported JVC 1D LUT applied to my JVC DLA-X700R, I first found out that that's not possible with the JVC auto-cal software for my model year (2014), but then happened upon Arve's JVC Projector Tools on GitHub.

That tool was written for model year 2015 and beyond, but with a small tweak it works for my projector too. The tool is primarily intended to create HDR gamma curves, which are no use to me as the 2014 model year did not yet feature HDR (or HDMI 2.0 for that matter).

I can download the contents of the Gamma > Custom 1/2/3 > Import slot on the projector, which results in a table with 256 10bit values for each primary colour. Arve's tool saves this in JSON format to a .conf file:

"table": [
[
0,
4,
8,
12,
16,
20,
24,
28,
...
1004,
1008,
1012,
1016,
1020
],
[
0,
4,
8,
12,
...

256 entries each for R, G and B.

Once loaded (or generated), it can then be uploaded to the projector to one of the three gamma Import slots.

My question: can I export a 256 value LUT with my current LightSpace HTL license or would this have to be added as a special export format? I'm willing to modify Arve's tool to add an import function, but want to know first if I can even export the data from LightSpace.

This could potentially make the grayscale calibration of the Projector a lot easier. In my case in particular, as JVC only allowed 2-point calibration on my model.

Author Steve

INF
Male
#2 | Posted: 14 Aug 2019 08:07 
I'm not actually sure what 1D LUTs the HTL version exports, other than the existing JVC and VCGT ones.
(Not in the office to check...)
But, with Excel you can easily modify the VCGT one to be the correct layout, and correct bit depth.

Any help?

Steve
Steve Shaw
Mob Boss at Light Illusion

Author ulrichd
ZRO
#3 | Posted: 15 Aug 2019 02:07 
Steve,

thanks for the suggestion: looks like I should be able to make it work with the VCGT exported file. I'll try adding a parser for it by converting the 16bit values to 10bit.

Author Omardris
ZRO
#4 | Posted: 15 Aug 2019 08:45 
@Ulrichd
If you have adapted "Class Model" for your projector accordingly, your further procedure is completely correct.
Use only the "FIT method" in LightSpace to calculate the LUT - this is in my experience the best method for the later gamma curve.
As export you take "Video_Card_Gamma_Table_16bits" and convert the 16-bit values into 10-bit values.
To test the conversion, you take a "zero cube" that must provide exactly the values of a 2.2 gamma curve.
I do the conversion with an Excel spreadsheet, which then delivers the corresponding output for the ARVE tool. If you can integrate this into the ARVE tool via Python, it is of course more comfortable.
The advantage is that the white point for the LUT is set manually as best as possible before the measurement.

I sent Steve the output structure for the ARVE tool a few months ago, but he probably didn't have time or resources to add it to LightSpace's export list.
Peter

Author ulrichd
ZRO
#5 | Posted: 15 Aug 2019 23:25 
Peter,

I'll do my best to get this implemented and Arve to add it to his tool, if he's still interested. Otherwise I'll look into deriving a dedicated "up/download" gamma tool from his code and hosting it on GitHub as well.

If all goes well it wouldn't require any additional work on Steve's part.

Thanks for the tips: should help with the testing.

Author Steve

INF
Male
#6 | Posted: 16 Aug 2019 13:35 
If we can help with any specifics, let me know.
(We are very busy though, so not a lot of 'free' time.)

Steve
Steve Shaw
Mob Boss at Light Illusion

Author KarlKlammer
ZRO
#7 | Posted: 16 Aug 2019 17:59 
@ulrichd
A few months ago, I wrote a small tool that can upload (and download) a VCGT file directly. But it is also limited to 2015 series and newer.
Are there any documents about the external commands for the 2014 series available?
And are you sure uploading and storing a gamma table to the X700 will work? I read some reports that the projector forgets the uploaded table once it is turned off.

Author ulrichd
ZRO
#8 | Posted: 17 Aug 2019 04:21 
Good news: got the importing and conversion bit done already last night. Will have to to test this next with my projector and then make it a bit more user friendly (adding a prompt for the file name or present a selection).

Ulrich

Author ulrichd
ZRO
#9 | Posted: 18 Aug 2019 21:15 
Just added a pull request on GitHub for the import feature. I ran a quick test last night with my projector and the table was uploaded with no issues. Still have to figure out how to best deal with model year 2014 support (that's not part of this pull request), as my changes for that would break the gamma up/download for model year 2015 and beyond.

Author ulrichd
ZRO
#10 | Posted: 20 Aug 2019 01:52 
@KarlKlammer

Sorry, only saw your message just now - could've saved me some coding!

Is your tool available somewhere publicly?

If you Google for "dla x700r communication specification" you should get a hit for a file called "RS_Model_2014_RS232_Command_Spec.pdf". It has the details of the serial and network protocol of the 2014 series. The essential difference to the following years is that to 2014 models expect one byte for Gamma Correction instead of two.

I can confirm that the "import" slot keeps the data (verified by uploading a table with only red values, so I could tell right away).

Author KarlKlammer
ZRO
#11 | Posted: 20 Aug 2019 06:47 
You were not able to read my message until yesterday, because it had to be "verified".

Thank you for the hints to the specifications. I will take a look at it. If it is just the usual changes it should not be too complicated to add the 2014 series.

I wrote the tool in VB.NET only for myself and some friends. So it is not publicly available. If you would like to use it, I can send it to you. But first I have to translate it a bit, because it is in german.
It has been tested with X5000, X9500, X7900 and NX9. I am rather positive that it will not cause permanent damage.

Author ulrichd
ZRO
#12 | Posted: 21 Aug 2019 02:08 
Sure, wouldn't mind giving it a spin... and no need to translate it first: German is my first language. Just don't know how you can get that to me. I don't think there is a way of sending private messages on this forum, is there?

In other news: the VCGT import feature is now officially part of Arve's tool as he accepted my pull request.

Author KarlKlammer
ZRO
#13 | Posted: 21 Aug 2019 05:27 
You can take my username and add (at)gmx.at to send me a mail.

Display Calibration Light Illusion Forums / Display Calibration /
 JVC gamma table upload

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