I installed media-video/mpv and it pulled media-video/libav which blocked media-video/ffmpeg. I had ffmpeg use flag set but media-video/mpv doesnt support it. When i set encode use flag the dependency changed to media-video/ffmpeg. I think media-video/mpv should have ffmpeg use flag. Reproducible: Always
You probably just need to change your USE flags for media-video/ffmpeg.
Ari, mpv needs ffmpeg or libav from ~: $ grep -e media-video/libav -e media-video/ffmpeg media-video/mpv/mpv-0.3.7.ebuild -2 RDEPEND+=" || ( >=media-video/libav-9:=[encode?,threads,vaapi?,vdpau?] >=media-video/ffmpeg-1.2:0=[encode?,threads,vaapi?,vdpau?] ) ... If you prefer ffmpeg, then you need to do 2 things: 1) Add media-video/ffmpeg to package.keywords 2) Add media-video/libav to package.mask