LG C8 Lut

Home Forums General Discussion LG C8 Lut

Viewing 9 posts - 211 through 219 (of 219 total)
  • Author
    Posts
  • #24687

    briandwagner
    Participant
    • Offline

    Is aiopylgtvcommand able to set the peak luminance values for HDR10 and DV on the 2019 models? I took a look at the source on github and found “set_tonemap_params” and “set_dolby_vision_config_data”. I’m just not sure what to do from here. Is it as simple as running the following if I wanted to change peak luminance to 750.0 and change nothing else?

    aiopylgtvcommand 192.168.XX.XX set_tonemap_params hdr_technicolorExpert luminance=750, mastering_peak_1=1000, rolloff_point_1=70, mastering_peak_2=4000, rolloff_point_2=60, mastering_peak_3=10000, rolloff_point_3=50
    
    aiopylgtvcommand 192.168.XX.XX set_dolby_vision_config_data white_level=750.0, black_level=0.0, gamma=2.2, primaries=BT2020_PRIMARIES

    Normally, I’d just try it and see what happens, but after reading about a bad DV config bricking a TV, I’m scared to just try something without being certain I’m doing it right.

    #25043

    János Tóth F.
    Participant
    • Offline

    I ran some test measurements on my C9 and found that it’s HDR panel mode (with the HDR tone mapping disabled on the SoC side by CalMAN) is now much closer to gamma 2.2 than it used to be on my C8 (which had a sort-of “S curve”). This is the result of a matrix-only 3DLUT calibration (done by CalMAN) with neutral 1DLUT. For some reason, that “S curve” of the C8 wasn’t corrected enough by a DisplayCAL generated 3DLUT.

    Attachments:
    You must be logged in to view attached files.
    #25575

    Josh Bendavid
    Participant
    • Offline

    Is aiopylgtvcommand able to set the peak luminance values for HDR10 and DV on the 2019 models? I took a look at the source on github and found “set_tonemap_params” and “set_dolby_vision_config_data”. I’m just not sure what to do from here. Is it as simple as running the following if I wanted to change peak luminance to 750.0 and change nothing else?

    aiopylgtvcommand 192.168.XX.XX set_tonemap_params hdr_technicolorExpert luminance=750, mastering_peak_1=1000, rolloff_point_1=70, mastering_peak_2=4000, rolloff_point_2=60, mastering_peak_3=10000, rolloff_point_3=50
    aiopylgtvcommand 192.168.XX.XX set_dolby_vision_config_data white_level=750.0, black_level=0.0, gamma=2.2, primaries=BT2020_PRIMARIES

    Normally, I’d just try it and see what happens, but after reading about a bad DV config bricking a TV, I’m scared to just try something without being certain I’m doing it right.

    I don’t think you can pass keyword arguments on the command line like that.

    For the tonemap_params given the default values for the other arguments you should be able to do just

    aiopylgtvcommand 192.168.XX.XX set_tonemap_params hdr_technicolorExpert 750

    For dolby vision you cannot do it like this without changing other things, because the default values correspond to BT2020 primaries and NOT the native wide gamut primaries of the TV.  So if you upload a dolby vision config with those values, it will mess up the colour.  Uploading a dolby vision config in this way is intended to be used in conjunction with a 3D LUT to map between BT2020 and the panel native colour space (in this case one can use the same 3d LUT for HDR10 and Dolby Vision in principle)

    If someone knows what the default primaries for the dolby vision configuration are, I can add this as an option to make it possible to keep these when uploading a DV config.

    As for the safety of these operations, I did indeed brick my 2018 set with a bad dolby vision configuration while working out the protocol.  I’ve tested the current aiopylgtv implementation of the dolby vision config upload with my 2018 set without issue and the configuration validity checking is fairly strict, but no guarantees of course.  I’ve not tested the set_tonemap_params at all, since I don’t have a 2019 set.

    #25891

    stama
    Participant
    • Offline

    @josh-2, I was wondering if you could step in the discussion on the 3D LUT creation for full range RGB input I started in the avsforum ColourSpace thread here.Ted claims that the TV internal 3D LUT can only by written by sending it a 3D LUT meant to transform 16-255 input signals (so limited range + WTW). I’m not so sure about that, since I have calibrated the TV for full range with DisplayCal and it seemed to work fine. Is he right and aiopylgtv does level mapping before uploading the 3D LUT to the TV?

    #25892

    Josh Bendavid
    Participant
    • Offline

    Sure I’ll have a look.

    aiopylgtv is not doing any level mapping itself aside from applying the offsets present in the cube file if present, according to the cube file format specification

    https://github.com/bendavid/aiopylgtv/blob/abc914d4ee7474851741d666cbd240f7cb0b8a7f/aiopylgtv/lut_tools.py#L98-L99

    https://wwwimages2.adobe.com/content/dam/acom/en/products/speedgrade/cc/pdfs/cube-lut-specification-1.0.pdf

    The behaviour of the tv in this regard depends on the black level setting, as well as the brightness and contrast settings.

    #25893

    stama
    Participant
    • Offline

    Ok, thanks! So, it’s as I imagined.Btw, if there’s anyone still using the 04.10.15 firmware version on their C8 as I did, please don’t do it anymore.The latest version 05.20.02 not only has a new setting in the service menu (GSR) to disable the undefeatable-till-now static dimming, but the TV does not dim as quickly and as badly even with it enabled compared to 04.10.15.

    #25894

    stama
    Participant
    • Offline

    @flhoech, does DisplayCal do levels mapping when creating the IRIDAS 3D LUT? Maybe this is why the lut can be uploaded to the LG TV?I did notice, btw, that the 3D LUT created by DIsplayCal is not the same as the one I get when using collink myself with the same profile icm file input and the same command line arguments. So I assume DisplayCal does some extra processing?

    #25976

    Justin
    Participant
    • Offline

    Hi All, I’ve gone through this entire thread and done a calibration of my LG C8. Unfortunately I’m not getting good results (report attached) so must have missed something. Hopefully someone can help.

    These are the settings I set on the C8

    profile: cinema
    contrast: 85
    Brightness:50
    OLED light: 25
    Saturation: 50

    I then used aiopylgtvcommand to reset the lut aiopylgtvcommand xx.xx.xx.xx upload_3d_lut_bt709 cinema

    The calibration/profile was run with the settings in the images attached. Before I ran the verification I uploaded the generated 3D LUT to my C8 using aiopylgtvcommand.

    Can someone tell me where I might have gone wrong?

    Attachments:
    You must be logged in to view attached files.
    #25983

    Justin
    Participant
    • Offline

    Please ignore the file profilename in the 3rd screengrab. I did some other tests afterwards and didn’t realise the name didn’t get recalled with the settings.

Viewing 9 posts - 211 through 219 (of 219 total)

You must be logged in to reply to this topic.

Log in or Register

Display Calibration and Characterization powered by ArgyllCMS