/usr/lib/x86_64-linux-gnu/libgstsdp-1.0.so.0 is in libgstreamer-plugins-base1.0-0 1.4.4-2+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgstsdp-1.0.so.0.404.0
/usr/lib/x86_64-linux-gnu/libgstsdp-1.0.so.0.404.0