This is the source for midiplay. The code is :

makefile
note.a       assembly language code to play a note (using BIOS calls).
midiplay.c   C code to read in and play MIDI file
written by James Allwright

midifile.h   C header file for midifile.c
midifile.c   C code for handling MIDI files
written by Tim Thompson and Michael Czeisperger with some
modifications by James Allwright

There is also a test MIDI file test.mid

The code has been compiled and linked using PCC (Personal C Compiler)
a shareware C compiler. If a different compiler is to be used, it is
likely that the assembly code routines will have to be altered as the
PCC assembler uses slightly non-standard syntax.

James Allwright
28th March 1997
---------------------------------------------------------------------

midiplay version 1.1
  usage :
midiplay midifile <options>
         -t <track>
         -c <channel>
         -s <semitones to transpose>
         -p <percentage of original speed> 100 = no change
         -i more information

     Midiplay
     --------
written March 1997 by James Allwright
using the midifilelib MIDI library.
karaoke capability added October 1998.

This program plays a MIDI file through the PC's internal
speaker. The output is monophonic, so some notes may be lost.
Where two or more notes should be played simultaneously,
midiplay plays the highest pitch one. If the MIDI file is
type 1, midiplay chooses the first non-empty track to play
unless some other track has been specified with the -t option.
While a file is playing, press any key to stop it.