Josh Bendavid

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 1 week, 1 day ago

    You can use the ddc_reset function in aiopylgtv to reset to a consistent state.  It has an additional boolean parameter reset_1d_lut to control whether the 1D LUT is reset or not.  Since the 2018 sets at least behave differently once the 1D LUT has been set/reset you may want to keep the factory 1D LUT, ie call ddc_reset(picMode, False)

    As soon a…[Read more]

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 4 weeks ago

    Ok, is that also true if I’m reading the .cal file directly to upload to the 1d lut in the TV?

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 4 weeks ago

    In order avoid DisplayCal and/or ArgyllCMS from messing further with the ranges, I needed to hack the code in DisplayCal, changing https://sourceforge.net/p/dispcalgui/code/6382/tree/trunk/DisplayCAL/madvr.py#l638 to always return (0., 255.) regardless of what level is actually set in madTPG.  (@fhoech is there a proper way of dealing with this,…

    [Read more]

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 1 month ago

    I think I uploaded the LG C8 .ccss but I can’t find it in the database.

    And I just remembered I was wary about using a ccmx because it’s a WRGB panel, so the pure R,G,B readings (captured for the gamut mapping) will be drifted by including W in the ccmx calculation. CalMAN didn’t show me by how much but DisplayCAL gave me an idea (probably de~0.…

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  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 1 month ago

    I test this by setting the 1D lut to all white except for the first and last elements which are set to output black, and the 3D LUT to unity.  The first and last RGB values which produce black are then as follows:

    SDR Black Level Low Brightness 50 Contrast 85: 66-1014

    SDR Black Level Low Brightness 50 Contrast 84: 65-1017

    SDR Black Level Low…[Read more]

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 1 month ago

    And with the rest of the attachments.

     

  • Josh Bendavid replied to the topic LG C8 Lut in the forum General Discussion 1 month ago

    Hi,

    A few more technical things.

    1. In order for any of the calibration and profiling to work properly, there has to be a proper mapping from 0.0-1.0 values being sent by ArgyllCMS and the first and last entries of the LUTs on the TV.  In order to get the proper alignment of values, I found that the following combination of black level,…

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  • Ok, at least one mistake I was making with Profile Only was to use Absolute colorimetric rendering intent.  Using Absolute Colorimetric with white point scaling seems to do something much more sensible when the white point is not pre-calibrated.

  • One thing to be aware of.  One shoudl NOT run “profile only” unless the white point is correctly calibrated to start with.

    Ie, even if one wants to use only the 3d lut for the TV, then one should still run the calibration step in DisplayCal (but in this case check enable “Apply calibration” in the 3D lut settings.)  Doing things this way with t…[Read more]

  • Are you sure the dithering behaviour is not changing when resetting the 1d LUT ?

  • The 1D LUT can be created by running the calibration procedure (ie by having Tone Curve set to anything other than “as measured” in the Calibration tab in displaycal).  Then the .cal file created with the profile can be uploaded.  Or was the question something different?

  • My understanding of the behaviour is that the 3d lut does not affect the tv menu/GUI (and I think also the GUI in smart tv apps)

  • In DV mode, the DV chip shall be allowed to handle all the 3D color mapping (dynamic metadata based tone mapping and color space conversion), so any such processing should be bypassed in the TV’s processor. It looks like it was more convenient for LG to leave these steps (like the 3DLUT processing) in the chain and use (most probably) neutral f…

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  • I did confirm that the additional matrices are active on the 2018 sets (by swapping the matrix rows and enjoying the messed up colors 🙂

  • A small update here.  In fact it looks like when starting calibration mode for a picture mode with factory 1D LUT, uploading a 3D LUT will also restore the stronger dithering behaviour.  (Possibly/probably sending any calibration data to the tv aside the 1D LUT will trigger this), so it’s not specifically related to these extra flags at least, w…[Read more]

  • Ok, some additional information, and mostly good news.

    Firstly, on the behaviour of these two mysterious flags 1D_2_2_EN and 1D_0_45_EN

    These both seem to be treated as booleans with default 0 (and in principle should be set to 0 as part of ddc reset).  Despite only being used by calman when addressing 2019 sets, these flags are valid for 2018…[Read more]

  • I have a OLED65C8PLA (EU model) btw.

  • Hmm. So you see more dither patterns in an accurate factory mode (say, Cinema) than in a CalMAN calibrated mode after your did a “full DDC reset”, finished programming both LUTs and quite from calibration mode? Do you also see more near-black flashing (on that test video with the rectangles on black background) in the calibrated mode? Is it an…

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  • Ok thanks, I’ll test with the latest version of Calman, since I realized I had only been using the penultimate version, and also try a factory reset (since I think I was on 05.10.20 the last time I did that)

    I see the same behaviour using (the latest version of) calman, and also after a factory reset, so I’m not sure why we’re seeing different t…[Read more]

  • Ok thanks, I’ll test with the latest version of Calman, since I realized I had only been using the penultimate version, and also try a factory reset (since I think I was on 05.10.20 the last time I did that)

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