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Transfer function for "ICtCp" should vary with method (PQ / HLG)

See original GitHub issue

https://github.com/colour-science/colour/blob/02b595b26313c4b4f55adc41d599f90c4c9edbcd/colour/models/rgb/ictcp.py#L192 This appears always to use eotf_inverse_ST2084 but should in fact use oetf_HLG_BT2100 if method is 'ITU-R BT.2100-2 HLG', according to the November 2020 revision of Rec. ITU-R BT.2100-2.

Issue Analytics

State:
Created 3 years ago
Reactions:1
Comments:9 (8 by maintainers)

Top GitHub Comments

1reaction

nick-shawcommented, Jan 29, 2021

IMHO, duplicated matrix in BT.2100-1 for HLG was just a bad typo, because the derivation of ICtCp matrix from IPT matrix must be different, so no need for all these duplications.

It may have been incorrect, but it existed in a published version of the paper. What we try to do with Colour is enable people to match any other implementation, current or historical. If somebody needed to match the processing in an application version released while the old matrix was published, they would need that option.

0reactions

KelSolaarcommented, Jan 30, 2021

What we try to do with Colour is enable people to match any other implementation, current or historical. If somebody needed to match the processing in an application version released while the old matrix was published, they would need that option.

Yes! 😃

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