yCMS - Color Management System

[cyberlolo]

@yesgrey: I think I've found a bug too with the Input_Range parameter. Please take a look at this two images: With Input_Range - Without Input_Range.

In the first one, you can clearly see the problem (I've added a white ellipse around it). In the second one, this problem is not there, but of course the levels are then wrong (they're 0-255 instead of 16-240).

I made both screenshots with enabled 3dlut, which was built with these settings. For the first image:

Input_Format NTSC YCbCr 8

Output_Format HD RGB_Video 16

Gamut_Measurements 0.6830 0.3170 0.3130 0.5810 0.1390 0.0500 0.2890 0.2800

Input_Range 16 240
Output_Range 0 255

For the second image, I used the same file, but removing the Input_Range parameter:

Input_Format NTSC YCbCr 8

Output_Format HD RGB_Video 16

Gamut_Measurements 0.6830 0.3170 0.3130 0.5810 0.1390 0.0500 0.2890 0.2800

Output_Range 0 255

Thanks in advance.

[yesgrey]

Originally Posted by cyberlolo

I think I've found a bug too with the Input_Range parameter.

Thanks for the report, it's the same bug. I'm currently working on it...

[cyberlolo]

Originally Posted by yesgrey

Thanks for the report, it's the same bug. I'm currently working on it...

Ok then, I thought it could be a different one, as this seemed to be caused by a different parameter.

Thanks again for your work.

[cyberlolo]

yesgrey, here is more info in case it can help you: I had a surprise today when I tested again the same video, and the problem had disappeared. The only things I made are:
1) Suspend+wakeup PC.
2) Enable ffdshow's levels filter+disable 3dlut in madVR. After that, I switched back by disabling ffdshow's levels filter and re-enabling 3dlut (using the exact same file than before) in madVR, and then everything was Ok. The problem has gone by now.

Weird. Isn't it?

[yesgrey]

Originally Posted by cyberlolo

(using the exact same file than before)

Which 3DLUT file (with or without the Input_Range command)?

[cyberlolo]

Originally Posted by yesgrey

Which 3DLUT file (with or without the Input_Range command)?

The one WITH the Input_Range command.

[yesgrey]

Yes, that's weird, though it doesn't help me...
I already know what the problem is, but I need to find time for correcting it...

[janos666]

I tried to add more low IREs to grayscale measurements to increase the shadow detail with gamma correction but I got an error that I should give the numbers in increaseing order. My IRE list was: 0, 1, 2, 3, 4, 10, 20, 30, 50, 70, 100. So, the real problem is that I should keep equal steps between values or I can not use too little steps.

Can you upload the v1.0 version for me? I can not enjoy any improvements/fixes but I have a bug which I didn't noticed with v1.0 (some - may be out-of-gamut - colors bands to black -> I don't know if this bug exists in v1.0 too but I didn't remember if I saw that)

[Mark_A_W]

Guys

How do I go from an HCFR measurement to a custom 3DLUT?

Can we do that yet?


Thanks

Mark

[janos666]

Do a measurement set with HCFR (primary colors and white will be enough for now but grayscale could be useful later, so choose the icon with the most rings...) and use copy-paste (CTRL+C and CTRL+V keys on your keyboard) the xyY values to a text file, delete the Y values and sort the xy values (in R G B W order) to a row and copy-paste it after the Gamut_Measurements command in your yCMS settings file.
You can do the same with grayscale RGB values but I do not think it is useful with current softwares.

[yesgrey]

Originally Posted by janos666

I got an error that I should give the numbers in increasing order. My IRE list was: 0, 1, 2, 3, 4, 10, 20, 30, 50, 70, 100. So, the real problem is that I should keep equal steps between values or I can not use too little steps.

There isn't such a limitation. The measures values should also be in increasing order, have you checked that? but that would not help you. I've already said that it's a bug. It's preferable to not use the Grayscale_Measurements command with the current version of yCMS. I'm working on it...

[iSeries]

Hi,

I'd like to have a go at creating a 3D LUT but to be honest after reading the 'manual' I am no more clued up than before. Is there a 'dummies' guide anywhere?

I have not calibrated my TV but someone on a well known AV forum posted profesional IRE calibration results. I've applied these through the 'Picture' menu of my TV (and improved colour 100%) but how can I apply these numbers to a 3D LUT?

Sorry for the newbie-ness

[janos666]

Originally Posted by yesgrey

There isn't such a limitation. The measures values should also be in increasing order, have you checked that? but that would not help you. I've already said that it's a bug. It's preferable to not use the Grayscale_Measurements command with the current version of yCMS. I'm working on it...

No, there were 11 numbers in increasing order, like I wrote and I got that message.
May be there were some fluctuation in the RGB luminance values and (for example) R-2% was less than R-1%. (I checked the "Average many readings" but my display do not has internal LUT for gamma and software LUT won't give me perfect result through 8 bit link. - After you released this new yCMS and I started to examine dark gradiations I feel that I need a new display. )
I just recalibrated my display and noticed this "Near Black Scale" tab in HCFR, so I thoght it won't harm if I give it a try. It won't be a bad idea to increase the max IRE number to 14 either. (To add this near black scale too - as an experiment. It looks like PVA displays without internal LUT has strange gradiation near to black. I didn't noticed it with my S-PVA earlier but it is clearly noticeable with c-PVA panels and exists here too.)


But can you upload yCMS 1.0 or the latest cr3dlut version for me? I can't remember if I saw something like this in the past (only with simple gamut correction): 3DLUT OFF - ON
I didn't keep any old versions and I would watch movies until your next yCMS release. Thanks.

Originally Posted by iSeries

Hi,

I'd like to have a go at creating a 3D LUT but to be honest after reading the 'manual' I am no more clued up than before. Is there a 'dummies' guide anywhere?

I have not calibrated my TV but someone on a well known AV forum posted profesional IRE calibration results. I've applied these through the 'Picture' menu of my TV (and improved colour 100%) but how can I apply these numbers to a 3D LUT?

Sorry for the newbie-ness

First:
Using measures from others can result in better or worse state as well. If every display would be identical then they wouldn't be calibrated at home (and recalibratead about monthly period), they could be easily calibrated in the factory. (Some manufacturers do this for their displays one by one and you only have to fine tune it at home, if you want...)
But native primary colors should be close (with identical brightness and contrast settings), so you can use those coordinates to do a gamut correction (if necessary).
Second:
If your display has configurable internal CMS then you are very lucky and you do not need software CMS. I do not know the capabilities of your hardware and what settings did you applied exactly...
Third:
Here is a template. You should change the last 4x2 values (four substantional value would be enougt - I just copy-pasted them...) . These are the x;y CIE coordinates of Red, Green, Blue, White colors (in this order).
As yesgrey wrote it earlier too, you should not try to use IREs for gamma correction with current software versions.
Filename: HD - PC.txt

# Source video format
Input_Format       HD YCbCr 8

#3DLUT output format
Output_Format      HD RGB_PC 16

# Gamut correction - measured native x;y coordinates
Gamut_Measurements 0.655471 0.330898 0.232747 0.689508 0.140942 0.090273 0.311221 0.327337

[iSeries]

Thanks janos666 - yes I'm aware using someone elses calibration results will not be 100% perfect, but trust me, its miles better than it was (even Cinema mode was too blue - my TV is a LG 47LH5000).

I have a Spyder3 - can I use this to get the necessary measurements? If so, what software should I use?

[janos666]

Originally Posted by iSeries

Thanks janos666 - yes I'm aware using someone elses calibration results will not be 100% perfect, but trust me, its miles better than it was (even Cinema mode was too blue - my TV is a LG 47LH5000).

I have a Spyder3 - can I use this to get the necessary measurements? If so, what software should I use?

Of course. It will be very easy if the display is connected to a PC through a digital cable and it won't be too hard if it is not.
Install this free software: Color HCFR.
Put some DLL files to it's folder from your bundled calibration software's folder if you asked to do it. (There will be a detailed notice later. Then start again from here...)
Start a new "View images" document, select your instrument from the list.
Set the output range of the image generator as your display requires it. (0-255 for PC monitors and sometimes for TVs which are connected to PC and normally 16-235 for TVs with any input source. You can figure it out with a quick test. Watch a black image. If it is black with 16-235 range then output setting is right.)
Do a complete measure set by clicking on the icon with many colored rings. Wait until it finished and save the document for later.
May be you have to cancel the first attempt and start it again if it would hang on showing a black image. I usually have to double click on the black image, wait, hit ESC, hit OK and start it a second time to do a correct measure set...

If you can't connect the display to a PC then you need the AVS HD 709 test patterns and play it back on your player to manually measure the primaries (or grayscale, ect.) in free measure mode.
But yes, I could figure it out that you have a PC because yCMS can be used with PC softwares (like madVR video renderer) only.

You can select the Primaries and Secondaries tab, set the xyY format and copy-past the R,G,B,W columns to a text file, clear the Y value and sort it.
Or you can choose the Grayscale tab and the RGB value format to get color luminance values for IREs.

Another thing: If you watch movies from your PC than you can use the calibration software to correct your gamma curve. The problem is that I do not know any free/bundle software which can work with a real Rec709 tonal response curve. But it won't be a problem if you target a gamma function like x^2.2. (I am not sure yet if in the real life, most HDTVs really use the Rec709 inverse transfer function or they have a simple gamma curve like x^2.2)

[Mark_A_W]

Originally Posted by janos666

Do a measurement set with HCFR (primary colors and white will be enough for now but grayscale could be useful later, so choose the icon with the most rings...) and use copy-paste (CTRL+C and CTRL+V keys on your keyboard) the xyY values to a text file, delete the Y values and sort the xy values (in R G B W order) to a row and copy-paste it after the Gamut_Measurements command in your yCMS settings file.
You can do the same with grayscale RGB values but I do not think it is useful with current softwares.

Originally Posted by janos666

Of course. It will be very easy if the display is connected to a PC through a digital cable and it won't be too hard if it is not.
Install this free software: Color HCFR.
Put some DLL files to it's folder from your bundled calibration software's folder if you asked to do it. (There will be a detailed notice later. Then start again from here...)
Start a new "View images" document, select your instrument from the list.
Set the output range of the image generator as your display requires it. (0-255 for PC monitors and sometimes for TVs which are connected to PC and normally 16-235 for TVs with any input source. You can figure it out with a quick test. Watch a black image. If it is black with 16-235 range then output setting is right.)
Do a complete measure set by clicking on the icon with many colored rings. Wait until it finished and save the document for later.
May be you have to cancel the first attempt and start it again if it would hang on showing a black image. I usually have to double click on the black image, wait, hit ESC, hit OK and start it a second time to do a correct measure set...

If you can't connect the display to a PC then you need the AVS HD 709 test patterns and play it back on your player to manually measure the primaries (or grayscale, ect.) in free measure mode.
But yes, I could figure it out that you have a PC because yCMS can be used with PC softwares (like madVR video renderer) only.

You can select the Primaries and Secondaries tab, set the xyY format and copy-past the R,G,B,W columns to a text file, clear the Y value and sort it.
Or you can choose the Grayscale tab and the RGB value format to get color luminance values for IREs.

Another thing: If you watch movies from your PC than you can use the calibration software to correct your gamma curve. The problem is that I do not know any free/bundle software which can work with a real Rec709 tonal response curve. But it won't be a problem if you target a gamma function like x^2.2. (I am not sure yet if in the real life, most HDTVs really use the Rec709 inverse transfer function or they have a simple gamma curve like x^2.2)

Janos, it seems to me from the first post that you are talking about doing Gamut cropping - as you are measuring primaries only, not greyscale.


But from the second post you kinda are talking about a custom gamma curve, which would need a greyscale measurement.


And we would need a target curve input somewhere.

What if I don't want the end result to be 2.2? What if I want, say, 2.5? Or a non-standard result?


It still seems to me that something is missing between the raw measurements and yCMS.


But we are getting somewhere

[cyberbeing]

Originally Posted by janos666

But there is a huge bug with the out of gamut colors (I think) in this version. Take a look at the blue area on the upper left corner: off - on

I've run into this problem as well with a couple different videos. The yCMS created LUT creates black blocks within portions of certain video sequences (repeatable). Until some of these bugs get fixed, I've rolled back to using cr3dlut which at least was 'stable' (yet no longer available on your website). Hint: It may be nice if you continued to make cr3dlut available until you can consider yCMS as being 'stable', without any significant bugs.

[iSeries]

@ janos666 - this isn't going to be as simple as I'd hoped! I've copied spyder3.dll to the install directory as it asked but when I try to start the measurements the software is saying 'Spyder3.dll returned an error during initialisation', and then 'Error during sensor initialisation'. Any ideas?

[yesgrey]

Originally Posted by Mark_A_W

What if I don't want the end result to be 2.2? What if I want, say, 2.5? Or a non-standard result?

That's the next thing I will take care after solving the current issue with Grayscale_Measurements. It's a subject that will need some discussion, so we'll get back to it after I fix the Grayscale_Measurements... Don't forget yCMS is still a new-born...

Originally Posted by cyberbeing

I've run into this problem as well with a couple different videos. The yCMS created LUT creates black blocks within portions of certain video sequences (repeatable).

I thought the problem only affected the Grayscale_Measurements command, but I've also fixed a bug that might affect the image even when it's not used.
Can you upload a small video sample? If that fixed bug solves the problem I will soon release a new yCMS version.

[cyberbeing]

Here you go (blocking appears in the blue haze around the 4 second mark):
http://www.mediafire.com/?mdmvmnyzqom

The other time it occurred it was in a blue area as well, but I forgot what video showed it. The image janos666 posted also had blocking in a blue area, so maybe it only effects blue? Or possibly any significantly out of gamut colors for any primary?

# Set input format
Input_Format   HD   YCbCr    8

# Set output format
Output_Format  HD   RGB_PC  16

# Display Gamut Measurements
Gamut_Measurements 0.626 0.343 0.294 0.607 0.149 0.078 0.3127 0.3290