src/mxmMidi/example_transpose_octave.py

   1 from MidiOutFile import MidiOutFile
   2 from MidiInFile import MidiInFile
   3
   4 """
   5 This is an example of the smallest possible type 0 midi file, where
   6 all the midi events are in the same track.
   7 """
   8
   9
  10 class Transposer(MidiOutFile):
  11
  12     "Transposes all notes by 1 octave"
  13
  14     def _transp(self, ch, note):
  15         if ch != 9: # not the drums!
  16             note += 12
  17             if note > 127:
  18                 note = 127
  19         return note
  20
  21
  22     def note_on(self, channel=0, note=0x40, velocity=0x40):
  23         note = self._transp(channel, note)
  24         MidiOutFile.note_on(self, channel, note, velocity)
  25
  26
  27     def note_off(self, channel=0, note=0x40, velocity=0x40):
  28         note = self._transp(channel, note)
  29         MidiOutFile.note_off(self, channel, note, velocity)
  30
  31
  32 out_file = 'midiout/transposed.mid'
  33 midi_out = Transposer(out_file)
  34
  35 #in_file = 'midiout/minimal_type0.mid'
  36 #in_file = 'test/midifiles/Lola.mid'
  37 in_file = 'test/midifiles/tennessee_waltz.mid'
  38 midi_in = MidiInFile(midi_out, in_file)
  39 midi_in.read()
  40