@MarsSeed: yes, I've discovered that around the same time you were commenting here. I was relying on an example from ArchLinux' wiki, but without any mention about the epoch. Thanks for notifying me.
I know ffmpeg 4.4 is now available, but I have to wait until ffmpeg package is updated before pushing the appropriate commit. Stay tuned.
Pinned Comments
oxalin commented on 2018-02-25 07:37
About GPG, it is up to you to import the missing public key. If you receive an error about it, this is ffmpeg's project public key. Something like the following should do the trick: gpg --recv-keys B4322F04D67658D8