3D LUT for HDR doesnt work

[Anonymous]

i get this error message after doing a 3D LUT for HDR

“This 3D LUT file does not match the input/output format required by madvr”

so what format for input ouput works and where do i change that?

[Florian Höch]

You’re trying to put it into the wrong slot in madVR – it needs to go under “convert HDR to SDR content by using an external 3DLUT”.

[Anonymous]

ok just what i thought

one question about max content brightness

My new tv Panasonic DX900 can output 1350nits

what i have seen so far is that with movies mastered at 1000nits it displays a perfect image without clipping.

but movies mastered at 4000nits the tv clips highlights and also the APL is raised so the overall picture is brighter than it should.

if i want the tv to clip at 4000 nits  can i set max content brightness in dispcal to 4000 then?

[Florian Höch]

if i want the tv to clip at 4000 nits can i set max content brightness in dispcal to 4000 then?

Note that this can introduce artifacts if the content goes above 4000 nits (e.g. some of the available HDR demos use the full ST.2084 brightness range despite having a significantly lower maxCLL in their metadata), so usually I would recommend leaving max content brightness at the nominal 10000 value. If you are absolutely 100% certain your content does not go above 4000 anywhere, not even briefly, then you can set it to 4000, and this will net you a comparatively small increase in max brightness of the brightest parts of the content.

[Anonymous]

ok i will try with diffrents luts and compare

i can already see that the hdr 3d lut with 10000 max tones down bright areas compared to the tvs build in hdr gamma.

so it does look better and the overall picture  brightness is lower

i will test and see if there is more details present on those movies that the tv clips highlights or if the 3d lut just tones down the highlights.

yes that maxCLL seems to be tricky

i know movies have diffrent maxCLL even if they are mastered at the same max brightness.

[Anonymous]

one example

if we take the movie Smurfs 2 (really reference quality here lol)

according to the list i have that movie is mastered at 4000nits

but maxCLL is at 1100nits

max fall is at 923nits

if i want a perfect hdr 3d lut just for that movie what max content brightness should i set then?

maybe a separete hdr 3d lut for each movie is the best :)?

one other example

Mad max fury road UHD

Max 4000nits

maxCLL here is  9766 nits!? (whats the difference with higher maxCLL?)

and max fal is at  3242 nits

[Florian Höch]

according to the list i have that movie is mastered at 4000nits

but maxCLL is at 1100nits

max fall is at 923nits

if i want a perfect hdr 3d lut just for that movie what max content brightness should i set then?

4000 to not clip anything (provided the movie really doesn’t go above that).

[Florian Höch]

maybe a separete hdr 3d lut for each movie is the best :)?

I would just use one, with max content level set to 10000. You’ll probably notice there isn’t much of a brightness difference to a 3D LUT with max content light level of 4000.

Mad max fury road UHD

Max 4000nits

maxCLL here is  9766 nits!? (whats the difference with higher maxCLL?)

and max fal is at  3242 nits

I would take this information with a big grain of salt. MaxCLL higher than actual encoded values doesn’t make sense.

[Anonymous]

thanks man

so its the max mastered nits you go after not maxCLL?

yes it seems strange

that list is probably wrong

i think they wrote down the values from what the  hdfury linker showed from the metadata

[Florian Höch]

so its the max mastered nits you go after not maxCLL?

The problem is the first is hard to know (unless you analyze the pixel values of each movie frame), and the latter can at worst be totally inaccurate.

[Anonymous]

also do you think its possible to add hdr metadata to madTPG so the tv switches to HDR mode ?

as it is now i need to manually change the gamma to  ST.2084 from the tv when i do profiling

[Anonymous]

Here you go

https://docs.google.com/spreadsheets/d/15pPvBMCjJogKxt4jau4UI_yp7sxOVPIccob6fRe85_A/edit#gid=184653968

this is another list of UHD movies metadata

[Florian Höch]

also do you think its possible to add hdr metadata to madTPG so the tv switches to HDR mode ?

This feature is planned.

[Anonymous]

i tested two different hdr luts one with 10000 max and one with 4000 max

i cant see no change in picture so as you said it does little.

[Florian Höch]

Btw, can you attach your HDR profile? Thanks.

[Author]

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