HCFR - Open source projector and display calibration software - Page 134 - AVS Forum
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post #3991 of 4014 Old 07-11-2014, 11:14 AM
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Originally Posted by zoyd View Post
Sounds like your meter does not always get a valid black reading or it's returning 0
Thanks, Zoyd. Should I input a value manually? If yes, any specific value?
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post #3992 of 4014 Old 07-11-2014, 11:19 AM - Thread Starter
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Using the 22% APL I would use 0.04 cd/m2
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post #3993 of 4014 Old 07-11-2014, 11:23 AM
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Using the 22% APL I would use 0.04 cd/m2
Thanks!
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post #3994 of 4014 Old 07-11-2014, 11:27 AM
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I was thinking about using this software, is it relatively easy to use and accurate?

How do you get started calibrating with it, is there an introduction to HCFR or a informational help file?
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post #3995 of 4014 Old 07-11-2014, 11:43 AM
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post #3996 of 4014 Old 07-11-2014, 12:20 PM
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Originally Posted by omenII View Post
Hello all, I'm planning on calibrating my Sony W905(UK W900) tonight using the latest HCFR and my new i1 Display Pro 3. It's been a few years since I did my last set using an i1 Display 2 and an older version of HCFR.

Skimming through this thread, am I right in thinking that I'm best off using a combination of the AVS709 greyscale patterns for white balance and the GCD 75% saturation patterns for colours? My W905 only has 2-point white balance and no CMS anyway.

Cheers.
Why would you not want to use the GCD greyscale patterns? Have I missed something?
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post #3997 of 4014 Old 07-11-2014, 12:24 PM
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Originally Posted by zoyd View Post
Also, don't use the plasma display type, it's not currently working right, use the LCD CCFL backlight.
Is the plasma display type working in the latest version 3.1.5?
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post #3998 of 4014 Old 07-11-2014, 12:26 PM
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Quote:
Originally Posted by dunan View Post
I was thinking about using this software, is it relatively easy to use and accurate?

How do you get started calibrating with it, is there an introduction to HCFR or a informational help file?

Pretty much if you go back
Maybe 10-20 threads where I started learning hcfr I asked a ton of noob questions and they were answered pretty quickly.

Thanks to those that helped that's for sure
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post #3999 of 4014 Old 07-11-2014, 12:53 PM
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Originally Posted by Geoff D View Post
Why would you not want to use the GCD greyscale patterns? Have I missed something?
I didn't realise GCD had greyscale patterns though I've seen them after downloading so will use them as well.

Which of the field patterns do I use for colours? And is there anything I need to set in HCFR to tell it I'm using 75% saturation patterns?

Thanks.
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post #4000 of 4014 Old 07-11-2014, 02:36 PM
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You can go under measures I believe and colors are in there
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post #4001 of 4014 Old 07-11-2014, 03:45 PM
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Quote:
Originally Posted by omenII View Post
I didn't realise GCD had greyscale patterns though I've seen them after downloading so will use them as well.

Which of the field patterns do I use for colours? And is there anything I need to set in HCFR to tell it I'm using 75% saturation patterns?

Thanks.
Ah, no worries. I thought there'd been some sort of difference flagged between the greyscale patterns in GCD and AVS.

As for 75%, go to advanced - preferences - references and change the colour space standard to HDTV REC 709 (75%)
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post #4002 of 4014 Old 07-11-2014, 10:19 PM
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Quote:
Originally Posted by Geoff D View Post
Ah, no worries. I thought there'd been some sort of difference flagged between the greyscale patterns in GCD and AVS.
GCD uses "round nearest" digital values, AVS uses "round down." But not to worry, the latest incarnations of HCFR have a switch for that.
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post #4003 of 4014 Old Yesterday, 02:19 AM
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Hi, I have a Samsung plasma TV 60f5000 and I am trying to learn about calibration.

I have made a first calibration with AVSHD709 disk but now I have used GCD with 10% APL, to avoid ABL as recommended.

I have also used the average version HCFR to overcome any inconsistense of my poor Colomunki Smile probe.

As also recommended, I have not used plasma display as option on HCFR but LCD CCFL (I don't know why, just did what was recommended).

For the colors, I uses 75%/75% ABL patterns with the option REC709 75% on HCFR.

Here are the results:

Gamma


Luminance


RGB Levels


Colors


Can anyone comment if I did right or wrong in any step: What do you think of these curves?

Thanks
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post #4004 of 4014 Old Yesterday, 02:35 AM
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Quote:
Originally Posted by HDTVChallenged View Post
GCD uses "round nearest" digital values, AVS uses "round down." But not to worry, the latest incarnations of HCFR have a switch for that.
Indeed, I just thought there was something more to it than that.

Ran another calibration last night on my Sony X9 after deciding I wanted to get a leetle more brightness out of the set, so I bumped up the backlight by another notch and got: average dE of 0.50 in the greyscale (CIE76), average dE of 0.90 on the primaries and secondaries, and average colour temp 6512K. I like my gamma at 2.2 and that's exactly what I got across the board (there's no 10-point control so I can't even attempt BT.1886). Ran the 24pt colour checker too, ended up with an average dE of 1.11.

That's probably the tightest calibration I've ever done, thanks to everyone in this thread for their help.
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post #4005 of 4014 Old Yesterday, 07:49 AM
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Hi, I've been fighting with my ST60 the last couple of days (choosing the right pattern for it is a pain!) and some things I'm still struggling with...

I used Mascior's patterns and tried to calibrate with 75A/75S but now trying to use HCFR's image generator as it automates the checking process and saves time.

1. REC.709-75% is set in preferences. That means that HCFR automatically displays color patterns @ 75A/75S and I should leave Pattern Intensity at 100 in Generator properties, right?

2. When I enter my gamma measured luminance in GCD_targets_v13.xlsx, the calculated xy for RGB is different than what HCFR calculates in CIE chart. E.g. HCFR shows 0.568/0.330 for Red@75%, but the spreadsheet shows 0.547/0.330 for 75/75. Which is correct?

3. How to manually display e.g. Red@75/75 pattern in HCFR?


Thank you!

Last edited by Touche; Yesterday at 07:56 AM.
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post #4006 of 4014 Old Yesterday, 08:04 AM
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Question regarding bt1886 (oh no - I know).

Just watched Episode 208 of Home Theatre Geeks to get more clarification regarding the bt1886 spec and found that most people even talking about it are bafoons (sic?), including even the types that write the spec...

When Joel Silver talked to TV manufactures he acknowledges that bt1886 is "too dark for lit room viewing" but it would be nice of them to implement it in a "nighttime mode".

When talking about his own setup Joel Silver mentions that he uses bt1886 ONLY in dark room conditions.

When comparing bt1886 to power gamma - Joel Silver is "happy that bt1886 is a FIXED curve" - as in "there is only one".

When talking about post processing environments he mentions that power 2.35 was used on certain CRTs (but that there is a huge variety).

When talking about projector calibration he mentions that his calibrators always shoot for at least 100cd/m2 (whitepoint).

When talking about the de facto post standards in studios that use bias lighting - he mentions that they use a white point of 120cd/m2 even for mastering.

Then he anecdotally talks about experimenting with customers, setting their home theatre rooms to 140cd/m2 and them "loving it".
-

So inside those statements there are at least 3 contradictions/errors of high magnitude.

For now I have but one question for zoyd, if you have the time. HCFR supports (and now defaults) bt1886. The bt1886 formula orients itself on the black point and the white point of the display you are calibrating?

Therefore the bt1886 curve can start at a gamma of lets say 1.9 (lowest point) > upon which it would be suitable for lit room viewing (blacks very visible).

But that in return invalidates the entire reason this standard is pushed upon > mimicking dark room mastering.

Question: wtf?

edit: From the ITU suggestion paper I collect that their argument for implementation is mostly "historical accuracy" to some standard "that wasn't accurate at all". At which point it becomes a mere matter of preference (there ought to be a standard, but which should the standard defining body pick?).

I also still have the question regarding the huge potential variability of the niveau of the curve (up, down) as seen in HCFR. How much of it is depending on the white point, how much of it is dependent on the black point (is the ITU suggesting two formulas should be used dependent on the black point?) (edit: Here is me trying to apply logic - the answer is "it depends" because black and white are both the (individually different) "pseudo" end points of the (greater) curve (which is always the same?)). Can there be a general statement for which "viewing environment" bt1886 aims - at all? Wasnt part of the original intention that the curve would be fixed (as in "set in stone, not movable at all").

Last edited by harlekin; Yesterday at 08:56 AM.
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post #4007 of 4014 Old Yesterday, 08:35 AM
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Quote:
Originally Posted by Touche View Post
Hi, I've been fighting with my ST60 the last couple of days (choosing the right pattern for it is a pain!) and some things I'm still struggling with...

I used Mascior's patterns and tried to calibrate with 75A/75S but now trying to use HCFR's image generator as it automates the checking process and saves time.

1. REC.709-75% is set in preferences. That means that HCFR automatically displays color patterns @ 75A/75S and I should leave Pattern Intensity at 100 in Generator properties, right?

2. When I enter my gamma measured luminance in GCD_targets_v13.xlsx, the calculated xy for RGB is different than what HCFR calculates in CIE chart. E.g. HCFR shows 0.568/0.330 for Red@75%, but the spreadsheet shows 0.547/0.330 for 75/75. Which is correct?

3. How to manually display e.g. Red@75/75 pattern in HCFR?


Thank you!
I asked this a while ago as well, from what I remember, it really depends on what you have your gamma settings in HCFR set to, i.e. if you have it set to 2.22, it will give you targets based on that number, whereas the spreadsheet is giving you numbers based on your actual measured gamma, which is probably a little different.

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post #4008 of 4014 Old Yesterday, 09:10 AM
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Originally Posted by CheYC View Post
I asked this a while ago as well, from what I remember, it really depends on what you have your gamma settings in HCFR set to, i.e. if you have it set to 2.22, it will give you targets based on that number, whereas the spreadsheet is giving you numbers based on your actual measured gamma, which is probably a little different.
I'm aiming for BT.1886. HCFR also changes the target based on what is measured, at least I see them moving if I change the values for Y.

EDIT: I've found your posts. Since "use measured" is disabled when BT.1886 is chosen, I'm not sure how HCFR is calculating the values. Does it show the targets for the ideal BT.1886 curve or for the measured result? If it is the former, wouldn't the spreadsheet values be more accurate for the current TV's state?

Last edited by Touche; Yesterday at 09:40 AM.
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post #4009 of 4014 Old Yesterday, 09:23 AM
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Originally Posted by Geoff D View Post
Indeed, I just thought there was something more to it than that..
Nothing that I'm aware of. Although the GCD disk is still officially a "beta" release. That being said, it's pretty hard to mess up the grayscale targets.
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post #4010 of 4014 Old Yesterday, 09:36 AM
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Originally Posted by harlekin View Post
Question regarding bt1886 (oh no - I know).

Just watched Episode 208 of Home Theatre Geeks to get more clarification regarding the bt1886 spec and found that most people even talking about it are bafoons (sic?), including even the types that write the spec...

When Joel Silver talked to TV manufactures he acknowledges that bt1886 is "too dark for lit room viewing" but it would be nice of them to implement it in a "nighttime mode".

When talking about his own setup Joel Silver mentions that he uses bt1886 ONLY in dark room conditions.

When comparing bt1886 to power gamma - Joel Silver is "happy that bt1886 is a FIXED curve" - as in "there is only one".
At times, I find that really smart people often have rather shocking knowledge/experience gaps. In this case, I suspect that Mr. Silver has very little "hands on" experience with displays that have poor black-levels (with the exception of front projectors which one wouldn't use in a "bright" environment anyway.) His "business" mostly deals with so-called "reference level" products. Therefore, I suspect that Mr. Silver has simply not encountered the full range of how BT1886 operates ... For a while, I had the same knowledge gap in reverse, as I had never encountered what BT1886 does on a display with "excellent" black-levels. I initially assumed that BT1886 would make everything look horribly washed-out based solely on spreadsheet modeling of my own IPS display. So there you have it: two widely different (but flawed) conclusions.

PS: For the rest of your post ... you appear to be inventing reasoning that is not apparent in the BT1886 "recommendation" as it is written ... at least as I recall it at the moment.

PPS: Yes HCFR is using your measured black and white levels to construct the BT1886 target luminance values. You need to do a greyscale run to get those values before you start tweaking ...

Final edit:
I suspect that the subject of EOTF's vs Gamma/gamma is a little more complex than what can be covered in a few minutes on a web cast and it may be that Mr. Silver was trying to "simplify" things a bit.

Last edited by HDTVChallenged; Yesterday at 09:58 AM.
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post #4011 of 4014 Old Yesterday, 11:26 PM
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The part of the reasoning I therefore would be inventing is "bt1886 is used to mimic dark room mastering".

So if it therefore is only used to mimic CRT characteristics (invented CRT characteristics) and the formula itself changes the low end gamma dependent on the black point to a gamma of "possibly around 1.9" - the ITU has invented a standard that happily configures panels differently dependent on a characteristic that no one really has a grasp on (apart from people with measuring devices) > black level.

So even if you calibrate for bt1886 - you cant make an assertion about in which lighting conditions it would be optimally viewed.

I understand that part of this question also has to do with "how much luminance can you cope with in dark viewing environments" and that there answers diverge hugely dependent on personal taste and the display being able to become "the predominant light source" ("turning nights into days").

Also in my tests in HCFR the bt1886 gamma curve did hardly move (0(=absolute) enabled) at a whole range of whitepoints (100 to 150 cd/m2), but Im told that it would shift greatly dependent on the black point. I would very much like some clarification on this point. (= Double, tripple, quadruple check if bt1886 implementation in HCFR is correct - the white point doesnt move the curve hardly at all - but the black point should extesively?)

Also - what does the ITU recommend for people that view content predominantly in daytime environments? Buy a TV with a worse black level? What message does that send to manufacturers (as your primary audience doesn't view content in theatre environments, never aim for deeper blacks)? And what about the mastering booths that use bias lighting? Displays would have great black levels, but their editing environment is 120 cd/m2 with bias lighting - so welcome the black crush?

This is insanity on a whole different level?

Also reagarding the Interview on Home Theatre Geeks. Scott W never asks any question regarding the subject he just laughs over some of the most cringingly and ludicrously worsening errors of some magnitude in the explanations made - but SURE - he does reviews and calibrates HDTVs himself... State of the industry, rly.

Last edited by harlekin; Yesterday at 11:36 PM.
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post #4012 of 4014 Old Yesterday, 11:54 PM
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Originally Posted by harlekin View Post
So even if you calibrate for bt1886 - you cant make an assertion about in which lighting conditions it would be optimally viewed.
Well, yes you can, on the basis of the historical context. BT.1886 is a recommendation based on the observation that historically video is mastered to reference CRT displays. CRT's are relatively low brightness devices, and hence to get any sort of decent image, need to be viewed in a dim environment. The originators of the TV systems took account of this in the way the video is encoded for broadcast, using a lower gamma than a CRT, so that there is a "bright studio" to "dim living room" viewing conditions adjustment built in. You can see this in the different curves for Rec709 encoding and BT.1886 decoding.

Now, if you are using an LCD that is capable of 3 or 4 times the brightness, you may well need to make an adjustment. BT.1886 doesn't attempt to cover such things - I guess it was a struggle to get as far as they did in standardizing the de-facto situation, and broadening such a standard is something "for future". Certainly the science of appearance is reasonably well establihsed.
Quote:
Originally Posted by harlekin
Also in my tests in HCFR the bt1886 gamma curve did hardly move (0(=absolute) enabled) at a whole range of whitepoints (100 to 150 cd/m2), but Im told that it would shift greatly dependent on the black point.
I wouldn't expect it to change at all with white level - the equation includes it so that the curve goes through the white, irrespective of what value that is. Since the usual view of such a curve is to normalize white to 1, then this cancels out the value of the white level in the BT.1886 equation.
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Originally Posted by harlekin
Also - what does the ITU recommend for people that view content predominantly in daytime environments?
Color science indicates that in this situation you should 1) Get a brighter display 2) Decrease your decode gamma slightly. You would raise your black level if there was a lot of added glare and you were loosing too much of the deep shadow detail, but it's a tradeoff with loss of contrast ratio. That's the main reasons that dim viewing environments are preferred.
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post #4013 of 4014 Old Today, 12:01 AM
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Is this the right assessment?
http://forum.doom9.org/showthread.ph...72#post1672972

Did 2.2 and 2.4 crush all our blacks on 0.04 blackpoint devices? How effectively was this tested against?

And also, if that is the case - why does contrast, specifically the white point seemingly hardly factor in into the equation at all?

Why does the black point induce the majority of the change in the gamma curve at its peak (white) points? My black effectively chooses if I should have 2.27 or 2.4 at the higher end. This is intended?

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post #4014 of 4014 Old Today, 12:11 AM
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@gwgill : If that is the case - we either have the state I was referring to - that we are optimizing for a standard that doesnt take room light levels into account at all - producing all kinds of different reaction curves

"never meant to be used for high brightness devices" - great, because even the latest Samsung plasma, ... *cough, cough*

Also - as the black point predominantly influences the "level" of the curve - was the intentional standard predominantly created with "devices with a very low black level" in mind (CRTs not very bright, but - good blacks (on mastering level)) -

So arent we therefore applying CRT characteristics to devices which INHERENTLY show different characteristics than the ones the standard was mimicked on? Brighter AND blacks that (on a user average) are far less deep?

And then we are making it the new standard?

As displays get brighter and (assuming) black level can be kept "very low" what does that mean for the standard - as white level seemingly doesnt influence the curve at all ("My black level influences the gamma of white")?

edit: "Dear TV manufacturers, please allow us to darken your Tvs picture on the top end and brighten it on the low end, to adher to an invented CRT standard?" All in the name of color reproduction the same as on the averaged mastering table - but with gamma curves (influencing color reproduction on the viewers end), which can widely differ - dependent on his black point?

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