/usr/lib/x86_64-linux-gnu/libtheoradec.so.1 is in libtheora0 1.1.1+dfsg.1-8.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libtheoradec.so.1.1.4
/usr/lib/x86_64-linux-gnu/libtheoradec.so.1.1.4