yCMS - Color Management System [Archive] - Page 3

yesgrey

13th June 2010, 11:50

I really don't understand the values : lv av pv threshold ?
Those values are the coefficients of the transfer function (aka gamma curve) used.

Is there a way to create a custom gamma curve with something like videoequalizer and then save it with the values ( lv/av/ap/threshold)

I mean, to adjust it graphically and then catch the values to paste into ycms.
Those values only can be used if the custom gamma curve is representable by a power function, which does not seem to be what you want.

I'm considering adding some functionality in that area to yCMS, but I don't know when...

j5627429

18th June 2010, 16:48

Hi yesgrey,

First of all, I would like to thank you and madshi for your all of your great contributions to the HTPC world.

I've been trying for a while now with cr3dlut and now with yCMS, and I still can't figure out a way to get my primaries spot on with REC709.

I'm using a colormunki spectrophotometer to measure, which should be fairly accurate.

Setup:
ATI 5770 set to output RGB 4:4:4
FFdshow Video Decoder set to 0-255
madVR set to 0-255
Projector set to RGB limited, 6500K, 2.2 gamma)

I used this code with your latest yCMS release:

Input_Format HD YCbCr 8
Output_Format HD RGB_PC 16
Gamut_Measurements 0.671 0.329 0.293 0.692 0.142 0.048 0.306 0.336

After applying the resulting 3dlut in madVR, my measured primaries are:
0.657 0.333, 0.286 0.609, 0.145 0.53

Which are much better than before but still not dead-on. I actually seem to recall getting a little bit more accuracy with the pixel shader method in EVR.

I have attached images of my before and after primaries.

Is there something that I'm not doing right or anything else that I can try?

Thanks in advance for your help!

kostik

18th June 2010, 17:15

yesgrey any progress about fixing the bugs with Grayscale_Measurements?
Thanks!

yesgrey

18th June 2010, 17:29

yesgrey any progress about fixing the bugs with Grayscale_Measurements?
Yes, they're fixed. I'm just cleaning up the code and making a few more tests before releasing the new version.

I still can't figure out a way to get my primaries spot on with REC709.
After fixing the problem above I've realized that if your display gamma curve is flawed you would only be able to get accurate gamut correction if you also perform gamma correction.

With the release of the new version I will also post some pictures showing this with my projector, which has a flawed gamma curve...

janos666

18th June 2010, 18:05

Yes, they're fixed.

Does it effect the Output_Transfer_Function command? I want to use that one because my gamma curve is already corrected through VGA LUT (gamma 2.2 for general PC usage...)

yesgrey

18th June 2010, 19:17

Does it effect the Output_Transfer_Function command?
Yes, but much less.

BeNooL

19th June 2010, 09:11

Setup:
ATI 5770 set to output RGB 4:4:4
FFdshow Video Decoder set to 0-255
madVR set to 0-255
Projector set to RGB limited, 6500K, 2.2 gamma)

Why set 0-255 (full range) everywhere but in the end set your projector to 16-235 (or limited) ?

j5627429

19th June 2010, 16:12

With the release of the new version I will also post some pictures showing this with my projector, which has a flawed gamma curve...

Great! Looking forward to it.

Why set 0-255 (full range) everywhere but in the end set your projector to 16-235 (or limited) ?

Should I be doing something different? I get really grey blacks If i set the projector to Expanded.

Honestly I'm not sure what the best way to set it up is. I don't mind if the PC desktop and games are innacurate. I just want to maximize the setup for optimum bluray playback. Should I set video card output to YCbCr 444 instead? Will MadVR and yCMS even work with that? Thanks for your help.

cyberlolo

19th June 2010, 16:56

Should I be doing something different? I get really grey blacks If i set the projector to Expanded.

Honestly I'm not sure what the best way to set it up is. I don't mind if the PC desktop and games are innacurate. I just want to maximize the setup for optimum bluray playback. Should I set video card output to YCbCr 444 instead? Will MadVR and yCMS even work with that? Thanks for your help.

May anybody correct me if I'm wrong, but my advice is to set madVR to TV Levels (unmolested), then set the projector to RGB Full, and finally create a 3dlut file adding this lines in yCMS for using it with madVR:

Input_Range 16 240
Output_Range 0 255

By the way, if you're using madVR, you'll need to output RGB. Always.

j5627429

19th June 2010, 20:05

May anybody correct me if I'm wrong, but my advice is to set madVR to TV Levels (unmolested), then set the projector to RGB Full, and finally create a 3dlut file adding this lines in yCMS for using it with madVR:

Input_Range 16 240
Output_Range 0 255

By the way, if you're using madVR, you'll need to output RGB. Always.

Okay I switched MadVR to TV levels and created an HD - Video.3dlut file with:
Input_Format HD YCbCr 8
Output_Format HD RGB_PC 16
Input_Range 16 240
Output_Range 0 255

This still gives me proper blacks only if I keep the projector in "Limited" mode. Expanded washes everything out.

Do I have to change the video card output to "RGB limited" also? And what about the video decoder? Should stay on 0-255 input , 0-255 output within the video decoder?

Thanks

cyberlolo

19th June 2010, 20:32

Okay I switched MadVR to TV levels and created an HD - Video.3dlut file with:
Input_Format HD YCbCr 8
Output_Format HD RGB_PC 16
Input_Range 16 240
Output_Range 0 255

This still gives me proper blacks only if I keep the projector in "Limited" mode. Expanded washes everything out.

Do I have to change the video card output to "RGB limited" also? And what about the video decoder? Should stay on 0-255 input , 0-255 output within the video decoder?

Thanks

Nope, you have to set the video card and the projector to Full RGB both. I think it's not working because you have to use this line:

Output_Format HD RGB_Video 16

instead of:

Output_Format HD RGB_PC 16

If it still doesn't work, please check the following:
1) Have you enabled the "use 3dlut" check box in the madVR settings dialog?
2) Is the created 3dlut file located in the madVR folder?
3) If you've only created a "HD - Video.3dlut" file, are you testing with a HD source video?
4) If you're using CoreAVC, do you have the Input and Output Levels set at Auto-detect?

yesgrey

19th June 2010, 23:18

This still gives me proper blacks only if I keep the projector in "Limited" mode. Expanded washes everything out.
Can you give us more info about your projector modes? Without knowing what exactly the "Limited" mode is I cannot help you...

And what about the video decoder? Should stay on 0-255 input , 0-255 output within the video decoder?
Don't worry with the video decoder. Those settings are used only when it outputs RGB, but when you use madVR the decoder outputs YV12, so you don't need to worry with those settings.

janos666

19th June 2010, 23:38

cyberlolo

20th June 2010, 01:04

j5627429

I think you should use RGB_PC output settings with full RGB range hardware setup or RGB_Video output settings with limited RGB range hardware setup.
"Expanded" mode sounds like it converts limited range to full range. So it should be used with RGB_Video output settings, but you shouldn't do that. (But this is only a guess.)
You shouldn't use the Output_Range command. It is already configured by the Output_Format command. (And you can mess your settings with duplications when you forget that they are duplicated and you try to edit only the first one...)

Maybe, but then he would not be able to keep some space over 235 for some excursions. That's why I recommended him a peak white value of 240, and that's only possible using RGB_Video instead of RGB_PC (which cuts any value over 235), and then using the Input&Output_Range commands.

j5627429

20th June 2010, 10:25

Nope, you have to set the video card and the projector to Full RGB both. I think it's not working because you have to use this line:

Output_Format HD RGB_Video 16

instead of:

Output_Format HD RGB_PC 16

If it still doesn't work, please check the following:
1) Have you enabled the "use 3dlut" check box in the madVR settings dialog?
2) Is the created 3dlut file located in the madVR folder?
3) If you've only created a "HD - Video.3dlut" file, are you testing with a HD source video?
4) If you're using CoreAVC, do you have the Input and Output Levels set at Auto-detect?

Okay I tried recreating the file with:
Output_Format HD RGB_Video 16
Input_Range 16 240
Output_Range 0 255
..and the blacks got even lighter.

1) yes
2) yes
3) yes
4) i was set to 0-255 0-255 in CoreAVC. However yesgrey just said that this doesn't matter.

Can you give us more info about your projector modes? Without knowing what exactly the "Limited" mode is I cannot help you...

I went back and verified it and the projector actually has three options: Standard, Expanded and Auto. Auto seems to have the same effect as "Standard" (it doesnt actually say "limited", sorry). This under the "HDMI settings". The projector is a JVC RS15. I'm using the standard cinema mode (cinema2) with 6500K color and 2.2 gamma selected, and all brightness and contrast and color sliders are set at the default middle position.

Don't worry with the video decoder. Those settings are used only when it outputs RGB, but when you use madVR the decoder outputs YV12, so you don't need to worry with those settings.
Good to know. Thanks!

janos666, That makes a lot of sense. Maybe I misunderstood what the projector is doing with the Standard and Enhanced setting. Here is what the manual says:
HDMI Input Level - Configures the input level setting of the HDMI input terminal.
Standard: For normal circumstances, select this setting.
Enhanced: Select this setting when the black-and-white of the projected image is unclear when RGB video signals are input from DVI devices.

I'll test the different configurations some more. It seems like setting madvr to video levels and using the Output Range command together with Output Format HD RGB_PC 16 to create the HD - Video.3dlut file looks exactly the same as keeping madvr at PC levels and not using the Output Range command (and naming the file HD - PC.3dlut of course)

yesgrey

20th June 2010, 12:21

The projector is a JVC RS15.

Here is what the manual says:
Standard: For normal circumstances, select this setting.
Enhanced: Select this setting when the black-and-white of the projected image is unclear when RGB video signals are input from DVI devices.

What manual is that? I've just downloaded the manual from JVC's site (http://www.service.jvcpro.eu/public/document.cfm?prog=InstrBook.cfm&Model=DLA-RS15) and look at what it says:
Standard: Select this when the dynamic range of the input images is 16-235.
Enhanced: Select this when the dynamic range of the input images is 0-255.

With this in consideration, you should use Standard when using RGB_Video output in yCMS, or you should use Enhanced when using RGB_PC output in yCMS - this is my recommended working mode.
If you are getting grey blacks with RGB_PC and Enhanced then it might be your graphics card drivers that are messing things up... I think I've read somewhere that sometimes they output video levels. Check that.

j5627429

20th June 2010, 13:53

What manual is that? I've just downloaded the manual from JVC's site (http://www.service.jvcpro.eu/public/document.cfm?prog=InstrBook.cfm&Model=DLA-RS15) and look at what it says:

With this in consideration, you should use Standard when using RGB_Video output in yCMS, or you should use Enhanced when using RGB_PC output in yCMS - this is my recommended working mode.
If you are getting grey blacks with RGB_PC and Enhanced then it might be your graphics card drivers that are messing things up... I think I've read somewhere that sometimes they output video levels. Check that.

That was from my old jvc rs2 manual because I couldn't find my rs15 manual. the function seems to operate in the same way, though I have to say the rs15 wording is much more clear.

Thanks for the help. I'm going to try different ati driver versions to see if I can get it to output pc levels.

yesgrey

20th June 2010, 14:51

I'm going to try different ati driver versions to see if I can get it to output pc levels.
Isn't there any driver setting for just that? or any registry key?

j5627429

20th June 2010, 19:22

Isn't there any driver setting for just that? or any registry key?

There is a setting in the "Video" section of the ATI driver panel that can be enabled and set to full or limited. However, I have tested it and it seems to have not effect whatsoever on either the desktop or the video.

Over at the AVSforum, it seems to be a known issue for some users of ati 5xxx cards, according to Andy o's thread (http://www.avsforum.com/avs-vb/showthread.php?t=1224697&highlight=rgb+full).

- Pixel Format RGB Full in some systems is broken, it seems to output desktop colors at the same levels as Limited. For some others (like me) this doesn't happen and RGB Full and Limited work as expected (Full outputs 0-255 and Limited 16-235). We don't know yet if the display affects the cards' output, but we're trying to test that.

I just tried plugging the projector straight into the video card, but the result is the same. The video card's Pixel Format setting of RGB 444 Full is using Limited levels.

yesgrey

20th June 2010, 21:34

I just tried plugging the projector straight into the video card, but the result is the same. The video card's Pixel Format setting of RGB 444 Full is using Limited levels.
It might not be exactly an issue...

Try this: instead of madVR use VMR9 or EVR, whether you are using XP or Vista/W7, and play a video without converting it to RGB. Let the renderer perform the conversion. Perhaps that setting only affects the conversion from YV12 -> RGB within the Microsoft renderers...
However, it should output always full RGB when feed with RGB, but let's consider that later...

Edit: It also might be a "smart" setting that detects you're using HDMI and then forces video levels... Have you tried connecting your projector with a DVI cable?

j5627429

21st June 2010, 16:24

It might not be exactly an issue...

Try this: instead of madVR use VMR9 or EVR, whether you are using XP or Vista/W7, and play a video without converting it to RGB. Let the renderer perform the conversion. Perhaps that setting only affects the conversion from YV12 -> RGB within the Microsoft renderers...
However, it should output always full RGB when feed with RGB, but let's consider that later...

Edit: It also might be a "smart" setting that detects you're using HDMI and then forces video levels... Have you tried connecting your projector with a DVI cable?

I haven't tried your first suggestion yet, but i did try using a DVI>HDMI adapter and sure enough, it is outputting PC levels. I had to change the HDMI setting of the projector to Expanded and everything looks normal.

I retook my red green and blue measurements with madVR set to 0-255 and 3dlut off, it looks like my x and y uncalibrated primary coordinates are no different than when my video card output was using video levels, so i guess my gamut correction problems are gamma related (as you mentioned earlier) and not related to the incorrect levels.

yesgrey

23rd June 2010, 10:26

yCMS v1.3 released

http://yesgrey.com/ycms.html

- The extension ".3dlut" is automatically added when missing.
- Video data below black and above white is not clipped anymore.
- Fixed RGB_Video setting. It was not working as it should.
- Removed parameter "mode" from Input/Output_Transfer_Function commands.
- Fixed Grayscale_Measurements command.
- Grayscale_Measurements command no longer supports measures for R,G,B.

Here it is.:)

The Grayscale_Measurements command should work fine now, but I recommend to be careful when using any measurements below 30 IRE. Some meters have lower accuracy at these levels, which might not give you good results...

All the reported cases with samples are working fine now, but I would like you to confirm that. If you could also post some images it would be even better.;)

I've removed temporarily the possibility of using measures for all color channels (R,G,B). I will add it again later.

When using the colorSpace setting RGB_Video yCMS was not working as it should. I would like users that have displays which support both video and PC levels to try both and verify if the image is exactly the same.

I will now prepare an example case...

Mark_A_W

23rd June 2010, 10:54

Please, we need a tutorial on the Greyscale Measurements function!!

yesgrey

23rd June 2010, 11:20

Please, we need a tutorial on the Greyscale Measurements function!!
I've just added my projector's calibration results on the third (http://forum.doom9.org/showpost.php?p=1402014&postcount=3) post (be a little patient because the pictures are waiting approval).

I will try to add later a more detailed explanation.

kostik

23rd June 2010, 12:09

So what measurments I need to put in Greyscale Measurements?
here is a picture with my Measurements from HCFR:

janos666

23rd June 2010, 21:59

I can see a firework with these settings (random pixels with full luminance primary colors):

# Source video format
Input_Format HD YCbCr 8

#3DLUT output format
Output_Format HD RGB_PC 16

Grayscale_Measurements
0 0.280090
10 1.301639
20 4.721668
30 11.083349
40 20.292418
50 33.596230
60 49.406956
70 70.420677
80 93.451164
90 122.102531
100 153.203751

# Gamut correction - measured native x;y coordinates
Gamut_Measurements 0.681838 0.306449 0.223260 0.699915 0.145035 0.063559 0.315212 0.329198

And this version doesn't want to create any LUT file with this command. (I copy-pasted it from the manual...)
Output_Transfer_Function 0 1.0 0.0 0.45 0.0

These are different numbers than I used to post earlier. This is not a mistake, I have a new display... :cool:

sepheas

23rd June 2010, 22:36

I've got a problem. When I want to créate a 3dlut file. Windows report me an error with the color management system. the service stopped.

Why ?

edit : yep it's the same thing. There's a problem with "output_transfert_function"

janos666

23rd June 2010, 22:59

I saw that error with v1.2 on a Vista x64 machine without the output_transfert_function command. I couldn't find any solution (run as admin, both x86 and x64 versions, ect...).
I didn't receive any error (Win7_x64) but it simply refused to create the file with that command.

yesgrey

24th June 2010, 00:52

I can see a firework with these settings (random pixels with full luminance primary colors):
Try without the measurements below 30 IRE. ;)

And this version doesn't want to create any LUT file with this command. (I copy-pasted it from the manual...)
Output_Transfer_Function 0 1.0 0.0 0.45 0.0
yep it's the same thing. There's a problem with "output_transfert_function"
Try without the first number after the command name.

Edit: I've confirmed that there is a bug in yCMS, because it shouldn't crash, but if you use the expected parameters it will work fine. I will correct this for not crashing when the wrong parameters are used, but only for next version.

yesgrey

24th June 2010, 01:03

Another thing. I've noticed some people use greyscale, while others use grayscale. I think both can be used, but I've named the command after the last one. I'm not English native, so I don't know which would be more accurate...

Can anyone enlighten me?

flanger216

24th June 2010, 03:13

Both are perfectly fine. One is more native to the UK, the other an American 'mutation,' but both are correct.

Mark_A_W

24th June 2010, 03:34

Yesgrey

Is it possible to add more data points? Like hundreds of them (obviously not manually)?

And can it be done separately for R, G and B? That's very important, to me at least.

Thanks

Mark

madshi

24th June 2010, 07:01

Hint: try without the measurements below 30 IRE. ;)
FWIW:

Yes, but even if the meter is giving bad results for < 30 IRE, that doesn't explain the "firework" janos666 is getting. Bad measurements below 30 IRE would explain problems like bad shadow detail or increased visibility or noise or things like that. But the "firework" points to a clear bug in yCMS.

yesgrey

24th June 2010, 11:31

Both are perfectly fine. One is more native to the UK, the other an American 'mutation,' but both are correct.
Thanks for the clarification. I will keep the current name then.

And can it be done separately for R, G and B?
Yes it can. I only disabled the separated measures to not further delay the release of the new version.

Bad measurements below 30 IRE would explain problems like bad shadow detail or increased visibility or noise or things like that. But the "firework" points to a clear bug in yCMS.
Yes, I will check that. I don't have yCMS immune to bad measures, yet.

yesgrey

24th June 2010, 11:41

And this version doesn't want to create any LUT file with this command. (I copy-pasted it from the manual...)
Output_Transfer_Function 0 1.0 0.0 0.45 0.0

Sorry, I missed that you have copy pasted it from the manual. :o
It's a typo in the manual. Remove the first 0 and it will run fine.

kostik

24th June 2010, 11:57

So what measurments I need to put in Greyscale Measurements?
can someone help me with this? I uploaded a pic of hscfr with my measurments some posts above.
thanks!

madshi

24th June 2010, 12:13

Yes, I will check that. I don't have yCMS immune to bad measures, yet.
Is there a way to detect bad measures with our eyes? I mean janos666's measurements look reasonable to me. How can we see if they're bad or not? JFMI...

yesgrey

24th June 2010, 17:19

So what measurments I need to put in Greyscale Measurements?
Only now the picture was displayed...

With the current version not accepting the grayscale for each color channel, you should change from RGB to xyY in the selection group you've pointed, and use the values of Y. Use values from 30 to 100 IRE.

kostik

24th June 2010, 17:22

Only now the picture was displayed...

With the current version not accepting the grayscale for each color channel, you should change from RGB to xyY in the selection group you've pointed, and use the values of Y. Use values from 30 to 100 IRE.

great thanks!

flanger216

24th June 2010, 17:29

I'm also a little surprised about the warning for low-IRE measurements. I have found that my Spyder 3 Pro does give wildly inconsistent results at low-IREs in HCFR, but that's at default settings: I've also found that if you set the read-time from 3000ms to something more like 9000ms, it gives me dead-on consistency out to three decimal places, pretty much every time. I realize consistency doesn't necessarily correlate to accuracy, but the low-IRE readings correspond to what I'm seeing with my eyes, make sense in terms of colorimetrical theory and, most importantly, I'm using my 10-30IRE measurements in yCMS right now and not seeing any problems. So what's the issue?

yesgrey

24th June 2010, 17:45

I'm also a little surprised about the warning for low-IRE measurements.
Ok, you're right, I was too cautious with my warning. I've rephrased it:
I recommend to be careful when using any measurements below 30 IRE. Some meters have lower accuracy at these levels, which might not give you good results...
I hope it's better now.;)

And it's good to know that you're having good results even with low IREs.:)

flanger216

24th June 2010, 18:41

Ok, you're right, I was too cautious with my warning. I've rephrased it:

I hope it's better now.;)

And it's good to know that you're having good results even with low IREs.:)

Ah, gotcha. I thought there was some inherent, theoretical reason that I wasn't understanding. But now it looks like, if it works, then use it!

BTW, it's looking freaking fantastic, yesgrey. I've never gotten this sort of performance out of my display before.

yesgrey

24th June 2010, 19:11

But now it looks like, if it works, then use it!
Yes, that's it.

BTW, it's looking freaking fantastic, yesgrey. I've never gotten this sort of performance out of my display before.
It's good to know that, and this is just the beginning... :)

yesgrey

24th June 2010, 19:17

Is there a way to detect bad measures with our eyes? I mean janos666's measurements look reasonable to me. How can we see if they're bad or not? JFMI...
The only way would be tracing the curve and looking at it to find any oddity, and even with that it might not be so simple...

janos666

24th June 2010, 22:55

This image shows the gamut coverage with native gmaut + yCMS 1.3 and U2410 in sRGB mode: HCFR - CIE charts (http://img12.tar.hu/janos666/img/77699490.png)
This display wins in the degree of the total uncovered + oversaturated areas. I think that blue would be oversaturated as well but my display can't show that color...
But I think I would choose the small oversaturation instead of the smaller oversaturations with an unnecessary clipping from the coverable gamut.

And here is a screenshot with the "firework" (I saw a different scene with more random colors when I gave it that name :p): click (http://img12.tar.hu/janos666/img/77701281.png)
I made it with this screenshot with the following settings:

# Source video format
Input_Format HD YCbCr 8

#3DLUT output format
Output_Format HD RGB_PC 16

Grayscale_Measurements
0 0.212637
10 1.141124
20 4.312172
30 10.302929
40 18.898254
50 31.034897
60 45.865826
70 64.588158
80 86.119484
90 112.591156
100 141.689590

# Gamut correction - measured native x;y coordinates
Gamut_Measurements 0.690234 0.299633 0.222931 0.703515 0.144627 0.062981 0.313639 0.330513

These are new measurements with different hardware settings. (I hate my new display. It was so cool when I tested my friend's one but I hate this one. I had to calibrate it from the factory menu to get a usable state. There was a serious mess in there... But my old and cheaper display looks better than this relatively expensive shit...)
I used HCFR 2.1 with an EyeOne and I set it to "Average many reads on dark measurements" mode. The display is calibrated to gamma 2.2 with the VGA LUT. (And it was in the native gamut.) But this is a crippled display anyway, so these measures can be wrong and my real gamma curve could be very strange. My LUT curves are strange...

I tried to use the Output_Transfer_Function 1.0 0.0 0.45 0.0 again but I don't think it is correct with v1.3 (as it never was...) or I don't think I would do a proper gamma correction. :p

yesgrey

25th June 2010, 20:00

yCMS v1.4 released

http://yesgrey.com/ycms.html

- Fixed "firework" bug on Grayscale_Measurements.
- Re-added support of different measures for R,G,B on Grayscale_Measurements.
- Increased maximum number of measurements on Grayscale_Measurements to 256.
- Fixed bug on Input/Output_Transfer_Function.

madshi

25th June 2010, 20:28

Very cool - congrats on the new version!

janos666

26th June 2010, 13:13

Yes, firework is gone. And you were right about the "wrong measures".
This Dell U2410 display is really sick. The standar mode has a gamma curve which lies around the gamma 1.8 curve and I tried to calibrate it with gamma 2.2 curve (by VGA LUT). The white balance is acceptable in the middle range but it is a complete mess near to black and white. (Other presets has their own sicknesses but I don't want to write too much about it in this topic...)
So, my measures were good readings but my display was a mess. I won't keep this industrial trash. :devil: