GerontoPlayer.library is a shared library making use of several open source libraries dedicated to playing sound files mainly from old game systems, through a simple to use unified API. This is basically just an extremely simple wrapper.
A plugin for AmiNetRadio makes use of it. This library is distributed under the LGPL licence.
Supported sound formats
The 
Blargg's Game Music Emulation library by 
Shay Green enables the support of the following formats (may be gzipped) :
* Nintendo NES (.nsf)
* Nintendo Super NES (.spc)
* Nintendo Gameboy (.gbs)
* Sega Master System (.vgm, .vgz)
* Sega Megadrive (.gym)
The 
SC68 library by 
Benjamin Gérard supports the following :
* Amiga and Atari ST (.sc68, over 90 replay routines)
* Atari ST (.snd(h))
STSound, by 
Arnaud Carré (http://leonard.oxg.free.fr) replays :
* Atari ST (.ym)
HESPlay, by 
Charles Mac Donald supports :
* Nec PC Engine (.hes)
libTimidity allows the replay of :
* MIDI (.mid)
.nsf, .gbs, .sc68 or .hes files may contain subsongs, usually all the music from a single game in one file.
Visit the 
GerontoLibrary site for more info and downloads.