My system being Debian Jessie 8.6, fully updated.
I have installed
x265 packages from official repositories.
On Linux Mint 18, there is no problem, it's just there.
On Debian 8.6, there is a package called
handbrake, on Linux Mint 18 I have added a PPA and installed
Versions seem to matter in this case:
Debian: 0.9.9 (x86_64)
Mint: 0.10.5 (x86_64)