Building media-video/totem-3.8.2 with +grilo USE flag pulls in media-libs/grilo but doesn't pull in media-plugins/grilo-plugins which leads to the following logs when launching totem:
(totem:28417): Grilo-WARNING **: [registry] grl-registry.c:440: Could not open plugins' info directory '/usr/lib64/grilo-0.2': Error opening directory '/usr/lib64/grilo-0.2': No such file or directory
Emerging media-plugins/grilo-plugins fixes the issue. The totem ebuild should depend on media-plugins/grilo-plugins when the grilo USE flag is set.
+*totem-3.8.2-r1 (14 Jul 2013)
+ 14 Jul 2013; Pacho Ramos <email@example.com>
+ +files/totem-3.8.2-vimeo-compat.patch, +totem-3.8.2-r1.ebuild,
+ -totem-3.8.0.ebuild, -totem-3.8.2.ebuild:
+ Apply upstream patch to be compatible with vimeo videos, pass configure
+ options properly (#475878 by Mark R. Pariente), USE grilo needs grilo-plugins
+ (#475886 by Mark R. Pariente, confirmed by me and seen in Fedora .spec), drop
+ old and broken versions.