Is Y variance common per device? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 03-13-2017, 04:38 AM - Thread Starter
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Is Y variance common per device?

Between my laptop using Calman internal TPG and Iscan Duo TPG, for 100 cd/m², I have about 1,5% variance for a 100% white patch @ 11% screen area. This measured with an I1 display 3 pro.

So calman's internal TPG 100% white patch will read 100 and the Iscan Duo's 98,5 cd/m².

Strange thing is, is that Calman always reads higher. But between WD LIVE and Calman I have about 4,5%. It it normal that sources vary by this much?

I don't have that many to try out so I can't make a good conclusion. In the screenshot you see the absolute difference for Y (3rd row)between the Calman TPG patches and the WDLIVE patches (GCD disk)
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My gear: Panasonic TH-42PF11EK pro plasma display + TX-P55VT60E -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer

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post #2 of 9 Old 03-13-2017, 09:50 AM
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It isn't uncommon. A few years back, someone measured output at 100% White for a number of DVD players, and there was quite a bit of variation between them. You'll also see it between sensors such as your I1D3 and I1Pro2.

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post #3 of 9 Old 03-13-2017, 09:55 AM
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By default CalMAN expands the built in pattern window to pc levels, which assumes your HDMI output is compressing the range back to video levels, if that is not the case, then you should disable expanding to PC levels. You can do this in the CalMAN settings under application preferences.

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post #4 of 9 Old Yesterday, 04:32 AM - Thread Starter
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Quote:
Originally Posted by WiFi-Spy View Post
By default CalMAN expands the built in pattern window to pc levels, which assumes your HDMI output is compressing the range back to video levels, if that is not the case, then you should disable expanding to PC levels. You can do this in the CalMAN settings under application preferences.
I unchecked the "expand" option. That way video black level 16 agreed between Calman and the GCD disk. I set the level with the GCD disc and then checked it using the Calman brightness pattern. Both methods agreed.

If I check the "Expand" option, brightness goes to 104 cd/m². My HMDI output sends 0-255 with black at level 16 and white at level 235.

My gear: Panasonic TH-42PF11EK pro plasma display + TX-P55VT60E -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #5 of 9 Old Yesterday, 04:58 AM
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Quote:
Originally Posted by Jeroen1000 View Post
Between my laptop using Calman internal TPG and Iscan Duo TPG, for 100 cd/m², I have about 1,5% variance for a 100% white patch @ 11% screen area. This measured with an I1 display 3 pro.

So calman's internal TPG 100% white patch will read 100 and the Iscan Duo's 98,5 cd/m².

Strange thing is, is that Calman always reads higher. But between WD LIVE and Calman I have about 4,5%. It it normal that sources vary by this much?

I don't have that many to try out so I can't make a good conclusion. In the screenshot you see the absolute difference for Y (3rd row)between the Calman TPG patches and the WDLIVE patches (GCD disk)
This is a common issue, since you don't have a video test signal analyser to see which device (or device settings) is outputting correct/incorrect the digital levels for each pattern, like DVDO AVLab TPG or Murideo Six-A, Quantum Data Analysers etc. the best think to do is just load a calibration disk (which has accurate patches for the calibration software you are using) from your player which are you using for movie playback and calibrate Grayscale and Color Gamut from there. It's 11 or 21 patches for Grayscale and 6 for colors, no big deal to do this manually and not automatically, since the end result will be better doing it manually since you will include to your correction adjustments settings the player output (from internal conversions or processing) error, or any additional conversions the TV can do internally when it will receive to it's input your player signal type (colorspace/bitdepth).

Each TV can 'like' better a specific signal (lets say 4:2:2 or 4:4:4), I mean when it receives it, to not do any additional (unwanted colorspace conversions) which may effect the signal (so to see differences to the measured levels for example).

LG OLED's 2016 for example when you send RGB-Video, it's lowering the luminance of the near black details compared to the YCbCr input signal which displays them a bit brighter, so if you use RGB-Video to calibrate even simple stuff like Brightness and then use YCbCr for playback you will have issues to near blacks. If you use RGB-Video for playback also, then you can fix the issue adjusting Brightness setting of the LG, this is just a quick example.

Ted's LightSpace CMS Calibration Disk Free Version for Free Calibration Software: LightSpace DPS / CalMAN ColorChecker / HCFR
S/W: LightSpace CMS, SpaceMan ICC, SpaceMatch DCM, CalMAN 5, CalMAN RGB, ChromaPure, ControlCAL
V/P: eeColor 3D LUT Box - P/G: DVDO AVLab TPG
Meters: JETI Specbos 1211, Klein K-10A, i1PRO2, i1PRO, SpectraCAL C6, i1D3, C5
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post #6 of 9 Old Yesterday, 08:28 AM - Thread Starter
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Quote:
Originally Posted by ConnecTEDDD View Post
This is a common issue, since you don't have a video test signal analyser to see which device (or device settings) is outputting correct/incorrect the digital levels for each pattern, like DVDO AVLab TPG or Murideo Six-A, Quantum Data Analysers etc. the best think to do is just load a calibration disk (which has accurate patches for the calibration software you are using) from your player which are you using for movie playback and calibrate Grayscale and Color Gamut from there. It's 11 or 21 patches for Grayscale and 6 for colors, no big deal to do this manually and not automatically, since the end result will be better doing it manually since you will include to your correction adjustments settings the player output (from internal conversions or processing) error, or any additional conversions the TV can do internally when it will receive to it's input your player signal type (colorspace/bitdepth).

Each TV can 'like' better a specific signal (lets say 4:2:2 or 4:4:4), I mean when it receives it, to not do any additional (unwanted colorspace conversions) which may effect the signal (so to see differences to the measured levels for example).

LG OLED's 2016 for example when you send RGB-Video, it's lowering the luminance of the near black details compared to the YCbCr input signal which displays them a bit brighter, so if you use RGB-Video to calibrate even simple stuff like Brightness and then use YCbCr for playback you will have issues to near blacks. If you use RGB-Video for playback also, then you can fix the issue adjusting Brightness setting of the LG, this is just a quick example.
Appreciate the advice. A signal analyser would be nice but not really useful enough for the non-pro. I have an Accupel DVG-5000 on the way. Used but the price was right.
That will give me a better reference to compare.

My gear: Panasonic TH-42PF11EK pro plasma display + TX-P55VT60E -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #7 of 9 Old Yesterday, 04:57 PM
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Quote:
Originally Posted by Jeroen1000 View Post
Appreciate the advice. A signal analyser would be nice but not really useful enough for the non-pro. I have an Accupel DVG-5000 on the way. Used but the price was right.
That will give me a better reference to compare.
Accupel DVG-5000 it will be a great way to use as a reference, comparing the readings you have from a calibration disk from your movie playback sources.

The advantage of signal analyser is that you exclude from the results any display in-stability or meter repeatabily, so you know exactly what is happening with digital error reports (while money are a lot for HT users, I agree, but it's the most accurate way to test any output setting combination).

Notebook's HDMI output usually can be accurate when they send RGB output but inaccurate when you send YCbCr.

Blu-Ray Player are doing the opposite, can usually have accurate output with YCbCr but inaccurate with RGB out. See for example some players I recently checked for digital errors: Oppo UDP-203 or Pioneer LX-91 or Sony BDP-S5200.

Ted's LightSpace CMS Calibration Disk Free Version for Free Calibration Software: LightSpace DPS / CalMAN ColorChecker / HCFR
S/W: LightSpace CMS, SpaceMan ICC, SpaceMatch DCM, CalMAN 5, CalMAN RGB, ChromaPure, ControlCAL
V/P: eeColor 3D LUT Box - P/G: DVDO AVLab TPG
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post #8 of 9 Old Today, 12:03 AM - Thread Starter
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Quote:
Originally Posted by ConnecTEDDD View Post
Accupel DVG-5000 it will be a great way to use as a reference, comparing the readings you have from a calibration disk from your movie playback sources.

The advantage of signal analyser is that you exclude from the results any display in-stability or meter repeatabily, so you know exactly what is happening with digital error reports (while money are a lot for HT users, I agree, but it's the most accurate way to test any output setting combination).

Notebook's HDMI output usually can be accurate when they send RGB output but inaccurate when you send YCbCr.

Blu-Ray Player are doing the opposite, can usually have accurate output with YCbCr but inaccurate with RGB out. See for example some players I recently checked for digital errors: Oppo UDP-203 or Pioneer LX-91 or Sony BDP-S5200.
Just for informational purposes (you seem to own every piece of kit worth having). Normally every "YCbCr" source should send something that gets decoded to 235,235,235 or with RGB no decoding is required. They should all end up at the same Y when measured with the same meter. 4 cd/m² difference between sources is too much to be a meter issue. I've also checked the TV does RGB and YCbCr equally well and verified the correct video levels. But I'll check again with the Accupel.

Anyway I'm wondering, how does the hdmi analyzer spot the error? Will you read pixel values like 232,232,232?

My gear: Panasonic TH-42PF11EK pro plasma display + TX-P55VT60E -- Iscan Duo video processor -- i1 display 3 colorimeter -- i1 pro 2 spectrometer
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post #9 of 9 Old Today, 03:57 AM
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Quote:
Originally Posted by Jeroen1000 View Post
Just for informational purposes (you seem to own every piece of kit worth having). Normally every "YCbCr" source should send something that gets decoded to 235,235,235 or with RGB no decoding is required. They should all end up at the same Y when measured with the same meter. 4 cd/m² difference between sources is too much to be a meter issue. I've also checked the TV does RGB and YCbCr equally well and verified the correct video levels. But I'll check again with the Accupel.

Anyway I'm wondering, how does the hdmi analyzer spot the error? Will you read pixel values like 232,232,232?
About digital level testing, if you see the links I posted with player test, I'm saying ''DVDO AVLab TPG Color Checker function (where it displays the digital level of the selected pixel on screen)''.



The cursor box provides key information about the current color format as well as the specific color values for the currently selected pixel.

For more details:

About Bit Depth; Color Checker can recognize 8, 10, or 12 bits per pixel. Upon receiving a video stream with properly formatted info frames and video information, the bit depth indicator will change to indicate the number of bits per pixel. The number of digits in the triplet values will also reflect this.
For 8 bits per pixel, the range will be 0-255 if displaying the value in decimal or 0-FF if displaying in hex.

About Decimal/Hex; For user convenience, the display can be adjusted to show the triplet values in either decimal or hex format. This is only a display setting and does not affect the video data.

About RGB/YUV; This indicates the current color space sent by the source. Note that this is derived from the info frame and indicates to a sink how to interpret the triplet information. An R in this space indicates RGB, and a Y indicates YCbCr. In this case, it tells the user how to interpret the triplet information.
Triplet. The actual color triplet information always consists of three values, either R,G,B or Y,Cb,Cr.

Ted's LightSpace CMS Calibration Disk Free Version for Free Calibration Software: LightSpace DPS / CalMAN ColorChecker / HCFR
S/W: LightSpace CMS, SpaceMan ICC, SpaceMatch DCM, CalMAN 5, CalMAN RGB, ChromaPure, ControlCAL
V/P: eeColor 3D LUT Box - P/G: DVDO AVLab TPG
Meters: JETI Specbos 1211, Klein K-10A, i1PRO2, i1PRO, SpectraCAL C6, i1D3, C5
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