/usr/lib/x86_64-linux-gnu/libavcodec-ffmpeg.so.56 is in libavcodec-ffmpeg-extra56 7:2.8.6-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libavcodec-ffmpeg.so.56.60.100