libopenmpt is a cross-platform C++ and C library to decode tracked music files (modules) [wikipedia] into a raw PCM audio stream. openmpt123 is a cross-platform command-line or terminal based module file player. libopenmpt is based on the player code of the OpenMPT project (Open ModPlug Tracker). In order to avoid code base fragmentation, libopenmpt is developed in the same source code repository as OpenMPT. libopenmpt ships with a plugin for XMPlay, xmp-openmpt. libopenmpt also provides a compatibility layer implementing the libmodplug interface on top of libopenmpt in the libopenmpt-modplug package. libopenmpt also did provide plugins for Winamp (in_openmpt) and foobar2000 (foo_openmpt) is the past. These are now deprecated in favour of WinAMP or WACUP which both provide their own plugin based on libopenmpt, and foo_openmpt54 which is a fork of foo_openmpt, respectively.