OSError: can’t find 'ffms2' library, but the library is there

[James-Carroll]

I remember something similar happening before.

Trouble getting a PIP Package to work as a snap

The problem comes down to Python’s ctypes.util find_library() having a dependency on /sbin/ldconfig, when the host has liblept installed, the snap works, if the host doesn’t, the snap fails. Even if the host has a copy of the library, the snap would still be using it’s own version bundled internally. The easiest fix would be to change the one line that even bothers looking for the library, because this is in a snap, we know the library will always where we put it. Keep the $LD_LIBRARY_PATH chan…

Likely you’ll need to patch your snap the same way as in the linked thread.