Please add support for Dolby Vision -> HDR10+ conversion as well as Wide Colour Gamut

[sagz]

I uploaded video files from an iOS device that encodes in HEVC, in BT.2020 in HLG, in Dolby Vision HDR (profile 8.4). video2commons should auto convert it to VP9, BT.2020 in HDR10+ (just HDR10 supports only static metadata, while HDR10+ will preserve frame-level dynamic metadata like DoVi has)

Currently, when I uploaded the file, this is the ffmpeg command I see Running cmd: /mnt/nfs/labstore-secondary-project/gentoo-prefix/usr/bin/ffmpeg -y -i /srv/v2c/output/9749bc75a4656065/dl.unknown_video -max_muxing_queue_size 4096 -threads 16 -row-mt 1 -crf 20 -qmin 1 -qmax 51 -b:v 0 -vcodec libvpx-vp9 -tile-columns 4 -auto-alt-ref 1 -lag-in-frames 25 -f webm -ss 0 -b:a 128000 -ar 48000 -acodec libopus -pass 2 -passlogfile /srv/v2c/output/9749bc75a4656065/dl.unknown_video.vp9.webm.log /srv/v2c/output/9749bc75a4656065/dl.unknown_video.vp9.webm

As you can see it doesn't do anything to preserve the HDR10+ metadata, nor the Wide Colour Gamut (BT.2020 HLG) that's in the video.

This post has sample ffmpeg commands to detect and use the appropriate flags https://codecalamity.com/encoding-uhd-4k-hdr10-videos-with-ffmpeg/