libgphoto2 is the core library designed to allow access to digital
camera by external programs. Here is an overview of the global
architecture:

It abstracts communication ports and camera protocol, to allow a
complete modularity. To support a new communication physical layer
(like IEEE1394), just add a new port to libgphoto2_port. To support
a new kind a digital camera, just provide a new camlib with the
required callbacks. All of this will be transparent to client
programs that call libgphoto2.

Homepage:
https://gphoto.sourceforge.io/
