/usr/bin/gnupod_convert_MIDI is in gnupod-tools 0.99.8-2.1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103  | #!/usr/bin/perl
#  Copyright (C) 2002-2007 Adrian Ulrich <pab at blinkenlights.ch>
#  Part of the gnupod-tools collection
#
#  URL: http://www.gnu.org/software/gnupod/
#
#    GNUpod is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 3 of the License, or
#    (at your option) any later version.
#
#    GNUpod is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.#
#
# iTunes and iPod are trademarks of Apple
#
# This product is not supported/written/published by Apple!
use strict;
use GNUpod::FooBar;
use GNUpod::FileMagic;
my $file  = $ARGV[0] or exit(1);
my $gimme = $ARGV[1];
my $quality = $ARGV[2];
if(!(-r $file)) {
 warn "$file is not readable!\n";
 exit(1);
}
elsif($gimme eq "GET_META") {
  print "_MEDIATYPE:".(GNUpod::FileMagic::MEDIATYPE_AUDIO)."\n";
  print "FORMAT:MIDI\n";
}
elsif($gimme eq "GET_PCM") {
  my $tmpout = GNUpod::FooBar::get_u_path("/tmp/gnupod_pcm", "wav");
  my $status = system("timidity", "-idqq", "-Ow", "-o", $tmpout, $file);
  
  if($status) {
   warn "timidity exited with $status, $!\n";
   exit(1);
  }
  
  print "PATH:$tmpout\n";
  
}
elsif($gimme eq "GET_MP3") {
  #Open a secure timidity pipe and open anotherone for lame
  #On errors, we'll get a BrokenPipe to stout
  my $tmpout = GNUpod::FooBar::get_u_path("/tmp/gnupod_mp3", "mp3");
  open(MIDIOUT, "-|") or exec("timidity", "-idqq", "-Ow", "-o", "-", $file) or die "Could not exec timidity: $!\n";
  open(LAMEIN , "|-") or exec("lame", "-V", $quality, "--silent", "-", $tmpout) or die "Could not exec lame: $!\n";
  binmode(MIDIOUT);
  binmode(LAMEIN);
   while(<MIDIOUT>) {
    print LAMEIN $_;
   }
  close(MIDIOUT);
  close(LAMEIN);
  print "PATH:$tmpout\n";
}
elsif($gimme eq "GET_AAC" or $gimme eq "GET_AACBM") {
  my $tmpout = GNUpod::FooBar::get_u_path("/tmp/gnupod_faac", "m4a");
     $tmpout = GNUpod::FooBar::get_u_path("/tmp/gnupod_faac", "m4b") if $gimme eq "GET_AACBM";
  $quality = 140 - ($quality*10);
  open(MIDIOUT, "-|") or exec("timidity", "-idqq", "-Ow", "-o", "-", $file) or die "Could not exec timidity: $!\n";
  open(FAACIN , "|-") or exec("faac", "-w", "-q", $quality, "-o", $tmpout, "-") or die "Could not exec faac: $!\n";
  binmode(MIDIOUT);
  binmode(FAACIN);
   while(<MIDIOUT>) { #Feed faac
    print FAACIN $_;
   }
  close(MIDIOUT);
  close(FAACIN);
  print "PATH:$tmpout\n";
}
else {
 warn "$0 can't encode into $gimme\n";
 exit(1);
}
exit(0);
#############################################
# Get Unique path
sub GNUpod::FooBar::get_u_path {
 my($prefix, $ext) = @_;
 my $dst = undef;
 while($dst = sprintf("%s_%d_%d.$ext",$prefix, int(time()), int(rand(99999)))) {
  last unless -e $dst;
 }
 return $dst;
}
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