When vapoursynth is selected, there is a circular dependency
CC'd maintainer of vapoursynth. Circle is caused by libass dependency of vapoursynth.
Try the following: 1. Build multimedia/vapoursynth with ASS=OFF 2. Build multimedia/ffmpeg with VAPOURSYNTH=ON 3. Build multimedia/vapoursynth with ASS=ON After review D16457 ffmpeg can be made to depend only on subpackage that provides libvapoursynth-script.so.
Resolved as of 69e0cbe8eaa6fb6fcb075774c4d8ef7b2a205bba