How to convert Dolby Vision HDR to HDR10+? I'd like to convert a file recorded from an iPhone 12 to a royalty-free version (for upload to Wikimedia, Flickr, etc). So the transfer involves:




Source (iPhone proprietary-encumbered)
Destination (royalty-free)




4k 60fps (UHD, not DCI)
4k 60fps


BT.2020 in HLG (WCG)
BT.2020 in HLG (WCG)


Frame-level dynamic HDR metadata in Dolby Vision profile 8.4
Frame-level dynamic HDR metadata in HDR10+


HEVC
VP9 (open to AV1 as well but that's likely more nascent)


Bitrate is 31 Mb/s
Fine with higher bitrate to maintain same SSIM/PSNR


Audio is in AAC
Audio to Vorbis/OGG




According to https://codecalamity.com/encoding-uhd-4k-hdr10-videos-with-ffmpeg/ it should be possible to do most of this.
Anyone can help me cook up the right command for this?
Sadly no, not without expensive specialist broadcast processing hardware.
From the Reddit link,

Dolby Vision is 100% proprietary. There is no incentive at all for
Dolby to convert anything to HDR10+ to help out Samsung users (and
pre-2019 Panasonics) when the only reason HDR10+ exists is because
Samsung didn’t want to pay Dolby for the license.
Dolby Vision is simply an enhancement layer on top of HDR10 which is
the base layer. There are a couple types of DV layers. The MEL
(minimum enhancement layer) and the FEL (full enhancement layer) which
reconstructs the original 12-bit signal. The FEL is what gives DV a
large advantage over HDR10 and HDR10+.
Page 12:
https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-for-creative-professionals/dolby-vision-uhd-bluray-authoring-workflow.pdf