For comparison, it takes 1m8.294s to convert all those frames to 1080p, 0m52.077s to encode them into a VP9 webm, and 0m7.170s to transcode that webm to HEVC mkv.
(Resizing done with imagemagick's mogrify, and encoding and transcoding done with the very spawn of the underworld itself, ffmpeg)
Art Progress, ffmpeg whine Afficher plus
I'm actually starting to understand ffmpeg I think. Soon I too will become video encoding software, as the ancient curse is passed down as said in the legends!