4.4.0-24.43) is not available, but a newer one is (4.4.0-142.168). We redirected you there.
/usr/lib/x86_64-linux-gnu/libmp4v2.so.2 is in libmp4v2-2 2.0.0~dfsg0-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libmp4v2.so.2.0.0