def __init__(self):
self.pattern = None
self.transcript = SongTranscript()
class TranscriptLoader(object):
"""
Reads the data from the midi file notes and loads it into a transcript
The class assumes the midi file is in the proper format(read above)
"""
def __init__(self):
self.pattern = None
self.transcript = SongTranscript()
def load(self, midi_file_name):
"""
First load the context, then loop through each track and load the notes from the tracks
"""
self.pattern = midi.read_midifile(midi_file_name)
logger.debug("Loaded Pattern From File")
logger.debug(self.pattern)
self.load_meta()
self.load_tracks()
def load_meta(self):
"""
Loads the metadata from the file into the transcript meta object which is then passed to the transcript object
"""
transcript_meta = TranscriptMeta(midiformat=self.pattern.format, resolution=self.pattern.resolution)
start_time = 0
for event in self.pattern[0]:
start_time += event.tick
if MidiUtils.is_key_signature_event(event):
transcript_meta.key_signature_event = event
if MidiUtils.is_time_signature_event(event):
transcript_meta.time_signature_event = event
if MidiUtils.is_set_tempo_event(event):
transcript_meta.tempo_dict[start_time] = event
self.transcript.set_transcript_meta(transcript_meta)
def load_tracks(self):
"""
Loops through each track after the meta track (the first one), and checks to see if there are any
notes in the track, and if there are, it proceeds forward to load them.
"""
for track_index in range(1, len(self.pattern), 1):
if MidiUtils.has_notes(self.pattern[track_index]):
self.load_track(self.pattern[track_index])
def load_track(self, miditrack):
"""
The main method for converting the track data into sound events
Loops sequentially through each event and does the following:
1. Update the current time from the event
2. If the event is a note on event, then create a new note and add it to the track
3. If the event is a note off event, then compute its duration
"""
present_time = 0
on_notes = {}
track = InstrumentTrack()
for event_index in range(0, len(miditrack), 1):
event = miditrack[event_index]
present_time += event.tick
if MidiUtils.is_new_note(event):
note = Note(start_time=present_time, pitch=event.pitch, volume=event.velocity)
on_notes[note.pitch] = note
track.add_note(note)
if MidiUtils.has_note_ended(event):
note = on_notes[event.pitch]
note.duration = present_time - note.start_time
instrument = MidiUtils.get_instrument(miditrack)
if instrument is None:
instrument = instruments.PIANO
self.transcript.add_track(instrument, track)