This package is deemed to support both media-video/ffmpeg and media-video/libav. Please move it to depend on virtual/ffmpeg. Thanks
http://sources.gentoo.org/media-tv/xbmc/xbmc-10.1.ebuild?r1=1.2&r2=1.3 http://sources.gentoo.org/media-tv/xbmc/xbmc-9999.ebuild?r1=1.79&r2=1.80