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-   -   Free LightSpace DPS - Manual Display Calibration (https://www.avsforum.com/forum/139-display-calibration/2155625-free-lightspace-dps-manual-display-calibration.html)

Light Illusion 10-02-2015 08:51 AM

Free LightSpace DPS (now LightSpace ZRO) - Manual Display Calibration
 
For those of you using the Free DPS version of LightSpace CMS, with the help of a bunch of Beta Testers, we have written a user Guide on Manual Display Calibration.

This is still a bit work-in-progress, but it's close enough to finished that it's worth linking to.

http://www.lightillusion.com/manual_...ots_guide.html

If anyone spots errors, omissions, grammatical issues, etc, feel free to flag them up!

Steve

Dominic Chan 10-02-2015 10:40 AM

Quote:

Originally Posted by Light Illusion (Post 37740689)
If anyone spots errors, omissions, grammatical issues, etc, feel free to flag them up!

Thanks for sharing. I have not tried the software, but have some comments on the guide based only on a cursory look:
1. There are four pictures showing potential display issues. The 4th one is mislabeled - it should be "Bad RGB Balance", not "Bad Gamma" (which is the 2nd picture).

2. "SET BLACK AND WHITE LEVELS".
- For the first option (using Direct HDMI and CalImages), I find the description confusing. It refers to setting to the TV Legal Range of 16-235, but I suspect it should instead refer to the full PC (or Data) Range of 0-255. The subsequent statement "meaning there will be no 'below black' or 'above white' bars as used from Disc sources" would be valid only for 0-255.
- For the second option (using Calibration Disc). As long as you are achieving the desired target luminance, there is no need or benefit in pushing the Contrast all the way up to make the 236 and above disappear. To high a contrast can cause other issues such as discoloration or colour clipping.

3. "SET PEAK WHITE". The illustration is not showing.

4. "SET GREY SCALE BALANCE". The two "rules of thumb" cannot be "combined". If (1) Green is not to be touched, and (2) RGB values should never be increased, then it would be impossible to correct for an excessive of Green, which is a very common problem with projector lamps.

Typos:
"THE TOOLBOX, Patch Generator". "Form most calibration work" should be "For most calibration work"
"THE TOOLBOX, Calibration Test Patterns". "... enables the calibration disc to be automatically play ..." should be "... enables the calibration disc to automatically play ..."
"as closing LightSpace DPS will loose (lose) any and all profile data collected"
"If desired a second or even third Quick profile can

If I have time I will try out the free Lightspace DPS and check it against the guide.
[EDIT: The program does not seem to work with the retail version of i1D3, which is what I have].

Light Illusion 10-03-2015 02:53 AM

Thanks Dominic, have made the obvious changes/corrections.

I'll work on making the 'Set Black and White Levels' easier to understand.

And good point on the 'Super White' clipping for some home TVs. I'm actually more use to professional displays, and they have specific settings for Data range and TV Legal (0-255, 16-235).

For home TVs it really depends on how the 'Contrast' control functions, compared to a 'Backlight' or 'Iris' type control.

As for the i1D3 question, please e-mail ConnecTED - http://www.displaycalibrations.com/contact_us.html

Steve

zoyd 10-03-2015 03:37 AM

Quote:

Originally Posted by Dominic Chan (Post 37743849)
[EDIT: The program does not seem to work with the retail version of i1D3, which is what I have].

Only the OEM version of the i1D3 is (officially) supported by LS.

Light Illusion 10-03-2015 04:02 AM

1 Attachment(s)
I should probably also say that we are aware of some of the limitations with the present 'Calibration Interface' GUI within LightSpace CMS, and we are working on those issues.

As a sneak-peak... at the moment the bar graph is not functioning correct, but you get the idea.

Steve

Dominic Chan 10-03-2015 05:33 AM

Quote:

Originally Posted by Light Illusion (Post 37762353)
As a sneak-peak... at the moment the bar graph is not functioning correct, but you get the idea.

Displaying the bar graph would be a welcome change. The current scheme relies on the user to adjust the RGB controls by looking at the x,y values, which is next to impossible for new users.

neox387 10-03-2015 10:12 AM

"Idiot's Guide" rofl :D

Light Illusion 10-04-2015 03:01 AM

Ok, I 'think' the Guide is now complete...
(Until you all point out the errors!)

:D

Dominic Chan 10-04-2015 07:39 AM

Quote:

Originally Posted by Light Illusion (Post 37783553)
Ok, I 'think' the Guide is now complete...
(Until you all point out the errors!)

Why would 20% grey correspond to 51, 51, 52?

Light Illusion 10-04-2015 07:48 AM

Oops - that will be one of those errors I mentioned...

:D

W3Rman 10-04-2015 11:54 AM

The manual is really looking good. I have always been impressed with LI website and the great information it provides. Since the new site overhaul it has improved greatly and now this additional guide. Thanks!

randal_r 10-05-2015 06:22 AM

Excellent work. Thank you for offering a free trial version, as I was interested in the software but was not willing to invest the money, only to find out that I may not like it.

I notice that for the DeltaE options that only 1976 and 2000 are offered. I am curious as to why 1994 was dropped.

With regards to legal television range 16~235, I agree with you. I have read this thread and agree with the individual. The Burosch video supports your statement of setting white levels. Since there really is no video content in the super white area, diminishing the "pop" factor of the image to try and view content that is not there seems senseless. The "Super White" features built into various consumer grade displays gravitate to the computer arena as opposed to the television arena. This function seems to be utilized for secondary devices such as the PS3. The statement regarding color shifting is a valid one, but this is due to the poor engineering of the display's controls. Even with displays with these deficiencies should still strive to get as close the the legal range as possible. All in all, we can all agree that the legal range is 16~235 and not 16~254.

Keep up the excellent work.

Light Illusion 10-05-2015 11:07 AM

Quote:

Originally Posted by randal_r (Post 37809505)
I notice that for the DeltaE options that only 1976 and 2000 are offered. I am curious as to why 1994 was dropped.

1976 is basically the 'original' Delta-E colour difference formula, and many users still refer back to it.

1994 attempted to correct for the perceptual non-uniformities with 1976, but basically failed due to a lack of reference data.

2000 correct this failure with refined definitions, and as a result is more perceptually uniform.

We therefore do not use 1994, as the data used has proven to be less accurate than 2000.

Hope that helps.

Steve

JimP 10-05-2015 12:29 PM

Can you use an K10A with this program?

Light Illusion 10-05-2015 12:44 PM

Yep - you can use ANY probe that LS is compatible with.

See: http://www.lightillusion.com/lightspace_ht_options.html

All the DPS options and capabilities can be seen there.

Steve

randal_r 10-05-2015 01:14 PM

Quote:

Originally Posted by Light Illusion (Post 37817361)
1976 is basically the 'original' Delta-E colour difference formula, and many users still refer back to it.

1994 attempted to correct for the perceptual non-uniformities with 1976, but basically failed due to a lack of reference data.

2000 correct this failure with refined definitions, and as a result is more perceptually uniform.

We therefore do not use 1994, as the data used has proven to be less accurate than 2000.

Hope that helps.

Steve

Thank you for the quick reply and the information.

randal_r 10-05-2015 01:14 PM

**

Dominic Chan 10-05-2015 01:17 PM

Quote:

Originally Posted by Light Illusion (Post 37762001)
I'll work on making the 'Set Black and White Levels' easier to understand.

On the setting of white level, the guide states that
Quote:

there are (presently) no consumer sources that ever contain valid content that is below 16 (64), or above 235 (940), so calibrating a home TV to 'allow' for Super White is just limiting the display unnecessarily, with no 'image' benefit at all - in fact, the exact opposite.
This statement seems to be at odds with the posts by Stacey Spears and Don Munsil:
https://www.avsforum.com/forum/139-di...l#post16498326
https://www.avsforum.com/forum/139-di...l#post16498839

In the same thread there are also those who question the "visibility" of whiter-than-white, but that's a separate argument.

Light Illusion 10-05-2015 01:40 PM

That looks just like 'compression ringing' and/or 'bit level inaccuracy' in the playback device to me.
I see no valid image detail there.

I have mastered a lot of material for TV and Disc delivery over the years.
(I have worked exclusively in the professional film and TV industry all my working life)
No broadcaster or mastering facility will ever accept master material with 'illegal' levels - and that means outside the 16-235 range.
there is a whole subsection of the broadcast industry dedicated to signal level verification.

Steve

Dominic Chan 10-05-2015 02:11 PM

Quote:

Originally Posted by Light Illusion (Post 37822257)
No broadcaster or mastering facility will ever accept master material with 'illegal' levels - and that means outside the 16-235 range.
there is a whole subsection of the broadcast industry dedicated to signal level verification.

For the 16-235 range, are you referring to the Y component of YCbCr, or to the R/G/B values? A (legal?) YCbCr value of 230-128-128 corresponds to R-G-B of 249-249-249.

Light Illusion 10-05-2015 02:37 PM

Predominantly the Y component of YCbCr, which directly equates to R/G/B 'legal' triplet levels.
CbCy is nominally 16-240, with 128 representing zero.

It is a real world of pain trying to get your head around all this.
Even though I've done this for years, I still have to go back and re-read the specs. to remind myself of what is what.

The bit that is key to remember is that the screen glass at the end of the image chain is always RGB, even if the signal input is YCbCr.

Steve

ConnecTEDDD 10-05-2015 02:51 PM

Quote:

Originally Posted by Dominic Chan (Post 37823105)
For the 16-235 range, are you referring to the Y component of YCbCr, or to the R/G/B values? A (legal?) YCbCr value of 230-128-128 corresponds to R-G-B of 249-249-249.

Hi Dominic,

YCbCr value of 230-128-128 corresponds to R-G-B of 249-249-249 when you convert YCbCr to RGB-Data Levels.

YCbCr value of 230-128-128 corresponds to R-G-B of 230-230-230 when you convert YCbCr to RGB-Video Levels.

Pres2play 10-05-2015 03:27 PM

Steve, great add-on to the other LS manuals.

Dominic Chan 10-05-2015 03:37 PM

Quote:

Originally Posted by ConnecTEDDD (Post 37824113)
YCbCr value of 230-128-128 corresponds to R-G-B of 230-230-230 when you convert YCbCr to RGB-Video Levels.

Thanks Ted, for the clarification. Are there no combinations of Y-Cb-Cr in the 235-240-240 range that correspond to RGB values outside the 16-235 video range?

It seems like even among the experts there are disagreements on whether there's any "real" information in the white-than-white range. Luckily most TVs these days, other than projectors, have enough luminance for optimal viewing even when Contrast is reduced from the maximum, so I'll just "play it safe" and leave some headroom above 235.

ConnecTEDDD 10-05-2015 04:23 PM

Quote:

Originally Posted by Dominic Chan (Post 37825257)
Thanks Ted, for the clarification. Are there no combinations of Y-Cb-Cr in the 235-240-240 range that correspond to RGB values outside the 16-235 video range?

It seems like even among the experts there are disagreements on whether there's any "real" information in the white-than-white range. Luckily most TVs these days, other than projectors, have enough luminance for optimal viewing even when Contrast is reduced from the maximum, so I'll just "play it safe" and leave some headroom above 235.

Dominic, if you convert any RGB Video value to YCbCr, you will never get 235-240-240.

YCbCr(legal) 235.240.240 = RGB(Video) 407.163.438

Dominic Chan 10-06-2015 05:44 AM

Quote:

Originally Posted by ConnecTEDDD (Post 37826465)
Dominic, if you convert any RGB Video value to YCbCr, you will never get 235-240-240.

YCbCr(legal) 235.240.240 = RGB(Video) 407.163.438

Those values are the individual maximum legal values; I was wondering if some combinations will be equivalent to R-G-B values >235 but <255.

ConnecTEDDD 10-06-2015 05:53 AM

Quote:

Originally Posted by Dominic Chan (Post 37837833)
Those values are the individual maximum legal values; I was wondering if some combinations will be equivalent to R-G-B values >235 but <255.

Dominic, imagine that a movie master which is Full Data Level (12 or 16bit) it's videoscaled (mapping of 0-255 to 16-235; I use as example 8bit values) to legal YCbCr for Broadcast/TV/Blu-Ray delivery. The numbers you posted can't be re-produced during that conversion.

Dominic Chan 10-06-2015 06:00 AM

Quote:

Originally Posted by ConnecTEDDD (Post 37838009)
Dominic, imagine that a movie master which is Full Data Level (12 or 16bit) it's videoscaled (mapping of 0-255 to 16-235; I use as example 8bit values) to legal YCbCr for Broadcast/TV/Blu-Ray delivery. The numbers you posted can't be re-produced during that conversion.

I was just trying to figure out how those "out-of-range" signals came about:
https://www.avsforum.com/forum/139-di...l#post16498326

ConnecTEDDD 10-06-2015 06:06 AM

Quote:

Originally Posted by Dominic Chan (Post 37838161)
I was just trying to figure out how those "out-of-range" signals came about:
https://www.avsforum.com/forum/139-di...l#post16498326

http://n1vqpq.bay.livefilestore.com/...5MzY3/POTC.png

The Black frame boarder (up/down) of the image of the Pirates of the Caribbean still has RGB Triplet 29.30.30 (lol). Ask Stacey to reply what kind of test is this?

If you can locate that still scene and tell me which of all Pirates is this (@ what time also), I can load the DVDO AVLab TPG ColorChecker Function to see if I can reproduce the same findings.

Dominic Chan 10-06-2015 07:03 AM

Quote:

Originally Posted by ConnecTEDDD (Post 37838337)
The Black frame boarder (up/down) of the image of the Pirates of the Caribbean still has RGB Triplet 29.30.30 (lol).

When I downloaded that screenshot and use the colour sampler tool in Photoshop CS6, the border is at exactly 16,16,16 and the white at 235, 235, 235.


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