MarsSeed [1] filed a request to merge ffmpeg21 [2] into ffmpeg2.1 [3]: Package got renamed by maintainer, and changed the two reverse dependencies to require the new one instead of the old.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ffmpeg21/ [3] https://aur.archlinux.org/pkgbase/ffmpeg2.1/
