HCFR - Open source projector and display calibration software - Page 217 - AVS Forum | Home Theater Discussions And Reviews
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post #6481 of 6494 Old 08-25-2015, 01:28 PM
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Quote:
Originally Posted by Rumble Devo View Post
What number should I enter following the BT 1886 selection?
Should I enter 2.4 for the expected Gamma?
You do not enter any value for the expected gamma when using BT.1886. The "effective gamma" is calculated automatically based on the measured white point and black point.

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Also, when measuring using BT 1886, should I use the Override black?
You don't normally need to use Override black, unless you find it difficult to get a consistent black level reading, or if you prefer a gamma curve different from the one calculated from the measured black point.
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post #6482 of 6494 Old 08-25-2015, 01:41 PM
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Originally Posted by Iceberg86300 View Post
Just your observations though. Unless you have a grey or white card to calibrate your camera's white balance it could be wildly changing images. Even with a good camera it could be mucking things up.
Even with an "accurate" grey card, you will still need to have a calibrated D65 light source. If you use light from the projector to illuminate the grey card, that will mask the errors that your trying to measure.

The only assessment you can make from posted photographs, is whether the colour temperature changes significantly throughout the range (which the OP's TV seems to do).
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post #6483 of 6494 Old 08-25-2015, 02:39 PM
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Quote:
Originally Posted by Dominic Chan View Post
Even with an "accurate" grey card, you will still need to have a calibrated D65 light source. If you use light from the projector to illuminate the grey card, that will mask the errors that your trying to measure.

The only assessment you can make from posted photographs, is whether the colour temperature changes significantly throughout the range (which the OP's TV seems to do).
Very true. However, I was just talking about simply using a grey card to set the custom white balance of the camera (if it has one) in whatever the calibrations viewing conditions are.

I guess accurate is the wrong word, apologies. It should be repeatable.


This would provide photos for us to check out for comparison from shot to shot only, and only when the camera is set for manual exposure.

If this is done conclusions can be made from photos that are taken at different adjustment values, and the direction of settings changes need to be noted.

In actuality, a grey card WB balance correction isn't even needed. The camera just needs to have WB correction set so it doesn't change from photo to photo (outdoor, incandescent, florescent, ect doesn't matter, just so long as it's fixed) and exposure needs to be locked as well.

Of course you can't calibrate from photos, but if trends can be seen by the use of multiple photos @ different settings better advice can be given.

Regards, (for the vast majority of people :-p)

Steve
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post #6484 of 6494 Old 08-25-2015, 03:24 PM
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Quote:
Originally Posted by Dominic Chan View Post
You do not enter any value for the expected gamma when using BT.1886. The "effective gamma" is calculated automatically based on the measured white point and black point.


You don't normally need to use Override black, unless you find it difficult to get a consistent black level reading, or if you prefer a gamma curve different from the one calculated from the measured black point.
Thanks.

Devo
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post #6485 of 6494 Old 08-25-2015, 03:49 PM
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Quote:
Originally Posted by Iceberg86300 View Post
This would provide photos for us to check out for comparison from shot to shot only, and only when the camera is set for manual exposure.
I think we are in general agreement, except for a few minor quibbles. (Presumably you meant manual WB, rather than manual exposure).

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The camera just needs to have WB correction set so it doesn't change from photo to photo (outdoor, incandescent, florescent, ect doesn't matter, just so long as it's fixed)
Maybe in theory, but in practice that's not quite true. The human eye is far more sensitive to the difference between 0 (neutral) and 1% blue, than between 30% blue and 31% blue. Correct WB for the reference is very important.

However, we are getting off topic. The real question is why his TV has such a strong blue bias.
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post #6486 of 6494 Old 08-25-2015, 04:23 PM
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Quote:
Originally Posted by Dominic Chan View Post
I think we are in general agreement, except for a few minor quibbles. (Presumably you meant manual WB, rather than manual exposure).


Maybe in theory, but in practice that's not quite true. The human eye is far more sensitive to the difference between 0 (neutral) and 1% blue, than between 30% blue and 31% blue. Correct WB for the reference is very important.

However, we are getting off topic. The real question is why his TV has such a strong blue bias.
Yeah, I agree on the agreeing LOL. Actually, I meant both. Anything but auto WB and also use manual exposure. Same ISO, same shutter, same aperture.

Definitely agree on the human eye. Also goes for camera's, which is why you want to kill all auto processing.

Just shoot it in raw LOL.

Basically, even a $5k camera with tons of adjustments will never be an accurate tool for calibrating TV's. But when used correctly it can be a valuable tool to convey certain problems to people on the net.

But yeah, back on topic.

This particular problem may require a venture into the service menu to knock out some blue, shifting the range for adjustment a bit. If that's even possible. Not familiar with this particular set.

Regards, (for the vast majority of people :-p)

Steve

Last edited by Iceberg86300; 08-25-2015 at 04:43 PM.
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post #6487 of 6494 Old 08-25-2015, 08:31 PM
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Does it make sense to use BT.1886 gamma for video games on IPS monitors? It seems to only make sense to use for FILMS, not video games. We don't know which gamma is used during film mastering and even if we do, we cannot always re-create that image due to difference between mastering TV's black levels and viewer TV's black levels. This is why BT.1886 gamma makes sense for film viewing/playback.

HOWEVER, almost all AAA games are exclusively developed on IPS monitors with ~1000:1 contrast ratio and power-law gamma 2.22 after calibration*. By using power-law gamma 2.22 to view video games, you actually WOULD get to see the image was it was developed. Therefore, BT.1886 is only useful for film viewing and possibly TN monitors with contrast ratio below 1000:1...

*Some game studios do not calibrate their monitors at all, in which case, it really doesn't matter which gamma curve tone is used - you're not going to see the game as it was developed as it is possible that each graphics designer saw the image differently due to lack of standardization...
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post #6488 of 6494 Old 08-25-2015, 09:34 PM
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Minor bug latest version

Hi Zoyd,

I found a minor bug. The colour checker on the measures page has a broken delete button and the button mouseover popup is using the text from the go button.
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post #6489 of 6494 Old Yesterday, 01:31 AM
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Quote:
Originally Posted by Iceberg86300 View Post
In regards to external sources, they should all output the same.

In reality they often don't, but this depends on what sources you have chosen as well as the TV.

I haven't really done any more calibrating, but thought I would do a little testing on how different devices handled the greyscale, with interesting results. Originally I would have sworn I could see differences when using different devices to run through the same test patterns, but all were pretty much in line with each other. This includes my Pioneer BD player, my Humax 4Tune PVR, and my Xbox One.

But when measuring the greyscale using my laptop connected directly via HDMI (to the same input source), the measured curve was noticeably higher. Additionally, the actual reference curve also seems to sit higher, so would there be a difference in the way the HCFR auto patterns are measured? Would my Windows theme settings (already calibrated via ColorMunki Display software) have an impact?

I have attached my greyscale checks for each device, as well as two images highlighting the difference between my regular sources and my laptop (HCFR Laptop via HDMI vs Pioneer BD player HDMI). Any thoughts on this? Note that the measurements were taken of Movie mode, uncalibrated with colour temp set to Low.

Cheers!
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Name:	Graph - AVSHD USB via Pioneer BD.png
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post #6490 of 6494 Old Yesterday, 07:11 AM
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Quote:
Originally Posted by Clemery76 View Post
But when measuring the greyscale using my laptop connected directly via HDMI (to the same input source), the measured curve was noticeably higher.
Is your TV set for full range (0-255) or limited range (16-235)? The "Laptop - HDMI direct - HCFR Auto" measurement shows a much higher black point and a lower white point, which usually indicates a range mismatch.

Quote:
Additionally, the actual reference curve also seems to sit higher, so would there be a difference in the way the HCFR auto patterns are measured?
Since you're using BT.1886, the reference curve will vary depending on the measure black point and white point.

Quote:
Would my Windows theme settings (already calibrated via ColorMunki Display software) have an impact?
If you have calibrated the display previously using the ColorMunki Display software, that will modify the test values being sent to the TV, unless you disable the loading of the LUT during startup.
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post #6491 of 6494 Old Yesterday, 02:08 PM
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Originally Posted by chchrlam View Post
Hi Zoyd,

I found a minor bug. The colour checker on the measures page has a broken delete button and the button mouseover popup is using the text from the go button.
Another minor issue: the "Override black" option is not being saved or compared for Preference Mismatch.
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post #6492 of 6494 Old Today, 02:04 AM
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Quote:
Originally Posted by Dominic Chan View Post
Is your TV set for full range (0-255) or limited range (16-235)? The "Laptop - HDMI direct - HCFR Auto" measurement shows a much higher black point and a lower white point, which usually indicates a range mismatch.


Since you're using BT.1886, the reference curve will vary depending on the measure black point and white point.


If you have calibrated the display previously using the ColorMunki Display software, that will modify the test values being sent to the TV, unless you disable the loading of the LUT during startup.

Movie mode does provide two Colour Gamut options: Standard or Extended. Would these basically translate to 16-235 vs 0-255? Perhaps that is whats going on.
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post #6493 of 6494 Old Today, 05:35 AM
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Quote:
Originally Posted by Clemery76 View Post
Movie mode does provide two Colour Gamut options: Standard or Extended. Would these basically translate to 16-235 vs 0-255? Perhaps that is whats going on.
The signal range should be independent of the Gamut options. In most cases, the "PC mode" uses 0-255, while other video modes use 16-235.

Last edited by Dominic Chan; Today at 06:26 AM.
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post #6494 of 6494 Old Today, 06:48 AM - Thread Starter
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Quote:
Originally Posted by Dominic Chan View Post
Another minor issue: the "Override black" option is not being saved or compared for Preference Mismatch.
This was intentional because use of the black override option is meant for a particular hardware set-up (probe + display) in which blacks can't reliably be measured. It's not a sharable preference like gamut options.
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