Upstream for proprietary app makemkv which has a free version and which has had ebuilds in portage for a few years has stated that their new version has the following requirements for either ffmpeg or libav: 1.0.x - for ffmpeg 0.8.9 - for libav I'm not sure if that makes sense - but it is what the upstream has posted. This, of course, is why virtual/ffmpeg exists but none of the existing slots matches the above. slot 9 requires libav9.0 and above, 0.10 allows for ffmpeg versions prior to 1.0. I will have to bypass the virtual and specify manual dependencies for newer ebuild until we get a necessary slot added.
requirements specified are minimum versions to be clear.
you should likely use a || instead of using the virtual, with the leftmost being what upstream (or you in case there is no strong preference) prefers both forks have distinct release cycles and it is hard to have versions of the virtual that match all the needs
This looks obsolete now as I see in current deps in ebuild: !libav? ( >=media-video/ffmpeg-1.0.0:0= ) libav? ( >=media-video/libav-0.8.9:0= )
