[astrange]

No, the HEIC has a proprietary attachment with the HDR data as well. You can see the iPhone display adapting when you view it in Photos.

[_aavaa_]

Do you have any info on how that attachment is stored/accesssed?

[illiac786]

I think I found it:

https://github.com/m13253/heif-hdrgainmap-decode

[_aavaa_]

Thanks! I'll take a look