/usr/lib/x86_64-linux-gnu/libgviewencoder.so is in libguvcview-dev 2.0.2+debian-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgviewencoder-1.1.so.1.0.1
/usr/lib/x86_64-linux-gnu/libgviewencoder-1.1.so.1.0.1