Как сделать, чтобы можно было работать с video в pHash?

misha@misha:~$ irb
irb(main):001:0> require 'phash/video'
Traceback (most recent call last):
8: from /usr/bin/irb:11:in `'
7: from (irb):1
6: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:39:in `require'
5: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:135:in `rescue in require'
4: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:135:in `require'
3: from /var/lib/gems/2.5.0/gems/pHash-1.2.1/lib/phash/video.rb:3:in `'
2: from /var/lib/gems/2.5.0/gems/pHash-1.2.1/lib/phash/video.rb:8:in `'
1: from /var/lib/gems/2.5.0/gems/ffi-1.9.25/lib/ffi/library.rb:273:in `attach_function'
FFI::NotFoundError (Function 'ph_dct_videohash' not found in [libpHash.so])