alternative transfer characteristics for HLG

[Former user]

Could alternative transfer characteristics SEI flag for HLG compatibility be added to x265?

"HEVC HDR UHDTV Bitstreams using HLG10 shall also contain the alternative_transfer_characteristics SEI message. The alternative_transfer_characteristics SEI message shall be inserted on the HEVC DVB_RAP, and preferred_transfer_characteristics shall be set equal to "18", indicating Recommendation ITU-R BT. 2100 [45] HLG system."

http://www.etsi.org/deliver/etsi_ts/101100_101199/101154/02.03.01_60/ts_101154v020301p.pdf

[Vittorio Giovara]

I would like to have this feature too.

[Marcus Forchner]

+1 -> this would really help to produce backwards compatible HLG files

[Tom Vaughan]

We’re looking into support for HLG, and talking to some folks who should be able to help. In the meantime, contributions are welcomed (in other words, if anyone has already modified x265 to support HLG, we would gladly accept their patches to make this part of the main repo).

[Marcus Forchner]

Thank you for the update Tom.

[Marcus Forchner]

Tom, are there any news on this topic, is an update in sight? ATM we are using SEIedit to manually set the correct bq compatibility in our files, it would be great to do this in x265 directly.