libdcp is a library to create Digital Cinema Packages (DCPs) from video, audio and subtitle data, and also to read and process existing DCPs.
Most of the hard work is done by a (slightly patched) version of asdcplib (http://www.cinecert.com/asdcplib/) which is included in the source distribution for libdcp.
libdcp is distributed under the GNU GPL.
An example of DCP creation is given in examples/make_dcp.cc.
An example of DCP reading is given in examples/read_dcp.cc.