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TDA4VH-Q1: CIE 1976 Standard in DCC? - Color space calibration

Dinesh bharathi
Intellectual 751 points
Part Number: TDA4VH-Q1

Hi Team, 

I would like to know what is the base standard considered in using the DCC tool Xrite calibration for CCM Generation. CIE 1976 is our requirement, I would like to know if the same is considered for DCC Calibration or some Newer standards.I should be able to achieve 99% of sRGB space under 1976 standard.  

Regards,
Dinesh

  • 0
    TI__Guru 59010 points

    Hi Dinesh,

    I recall that by default BT709 gamma is used in TDA4 SDK.
    For sRGB, you may need to change the default gamma curve in SDK.

    On tuning tool side, you may input your own "Target/Reference" JPG and the gamma LUT in color correction plugin.
    That allows you to control both output color and gamma curve.

  • 0 in reply to Gang Hua
    Intellectual 751 points

    Hi Gang,

    So, i think am fine with  BT709 which kind of aligns with my requirement. 
    If I dont give any values and align my inputs with the Xrite chart as given in the DCC tool, Should i apply gamma or this get applied by default?

    Also I have a query what happens if the display is based on 1931 CIE based than 1976 based. will there be any effect do i have to modify to align my CCM and Gamma to fit inside CIE 1931? 

    Also on the whole how does this go along with the forward Perception LUT. What does that represent here in terms of color/luminance reproduction, Is it just the gamma termed as Forward Perception LUT

    Regards,
    Dinesh

  • 0 in reply to Dinesh bharathi
    TI__Guru 59010 points

    Hi Dinesh,

    I suppose you are talking about the target color.
    That is specified by the "Target/Reference Image" tab.

    You may prepare a JPG or PNG image with your desired RGB values (after Gamma) for the 24 patches, which corresponds to your desired final RGB input for your display.
    These RGB values are what really matter for tuning tool.
    As long as the gamma used in your JPG/PNG image matches your "Gamma Contrast LUT" tab, tuning tool will optimize CCM as expected.

    Dinesh bharathi said:
    Also on the whole how does this go along with the forward Perception LUT.

    This is for local tone mapping and it should not change the color.

  • 0 in reply to Gang Hua
    Intellectual 751 points

    Hi Gang,

    What is the Gamma for the current default reference image? where can i get this gamma table in the default setup.

    Regards,
    Dinesh

  • 0 in reply to Dinesh bharathi
    TI__Guru 59010 points
    Dinesh bharathi said:
    where can i get this gamma table in the default setup.

    The current gamma LUT is in the default settings of VISS tiovx kernel "vx_vpac_viss_target_default.c".

    For the target image, only the RGB values matter practically as they are after gamma.