import random
from typing import Dict, Any
import PIL.Image
import numpy as np
class MIDITokenizerV1:
def __init__(self):
self.version = "v1"
self.optimise_midi = False
self.vocab_size = 0
def allocate_ids(size):
ids = [self.vocab_size + i for i in range(size)]
self.vocab_size += size
return ids
self.pad_id = allocate_ids(1)[0]
self.bos_id = allocate_ids(1)[0]
self.eos_id = allocate_ids(1)[0]
self.events = {
"note": ["time1", "time2", "track", "duration", "channel", "pitch", "velocity"],
"patch_change": ["time1", "time2", "track", "channel", "patch"],
"control_change": ["time1", "time2", "track", "channel", "controller", "value"],
"set_tempo": ["time1", "time2", "track", "bpm"],
}
self.event_parameters = {
"time1": 128, "time2": 16, "duration": 2048, "track": 128, "channel": 16, "pitch": 128, "velocity": 128,
"patch": 128, "controller": 128, "value": 128, "bpm": 256
}
self.event_ids = {e: allocate_ids(1)[0] for e in self.events.keys()}
self.id_events = {i: e for e, i in self.event_ids.items()}
self.parameter_ids = {p: allocate_ids(s) for p, s in self.event_parameters.items()}
self.max_token_seq = max([len(ps) for ps in self.events.values()]) + 1
def to_dict(self) -> Dict[str, Any]:
d = {
"version":self.version,
"optimise_midi":self.optimise_midi,
"vocab_size": self.vocab_size,
"events": self.events,
"event_parameters": self.event_parameters,
"max_token_seq": self.max_token_seq,
"pad_id": self.pad_id,
"bos_id": self.bos_id,
"eos_id": self.eos_id,
}
return d
def set_optimise_midi(self, optimise_midi=True):
self.optimise_midi = optimise_midi
@staticmethod
def tempo2bpm(tempo):
tempo = tempo / 10 ** 6 # us to s
bpm = 60 / tempo
return bpm
@staticmethod
def bpm2tempo(bpm):
if bpm == 0:
bpm = 1
tempo = int((60 / bpm) * 10 ** 6)
return tempo
def tokenize(self, midi_score, add_bos_eos=True, cc_eps=4, tempo_eps=4,
remap_track_channel=None, add_default_instr=None, remove_empty_channels=None):
if remap_track_channel is None: # set default value
remap_track_channel = self.optimise_midi
if add_default_instr is None:
add_default_instr = self.optimise_midi
if remove_empty_channels is None:
remove_empty_channels = self.optimise_midi
ticks_per_beat = midi_score[0]
event_list = {}
track_idx_map = {i: dict() for i in range(16)}
track_idx_dict = {}
channels = []
patch_channels = []
empty_channels = [True] * 16
channel_note_tracks = {i: list() for i in range(16)}
for track_idx, track in enumerate(midi_score[1:129]):
last_notes = {}
patch_dict = {}
control_dict = {}
last_tempo = 0
for event in track:
if event[0] not in self.events:
continue
c = -1
t = round(16 * event[1] / ticks_per_beat) # quantization
new_event = [event[0], t // 16, t % 16, track_idx] + event[2:]
if event[0] == "note":
c = event[3]
if c > 15 or c < 0:
continue
empty_channels[c] = False
track_idx_dict.setdefault(c, track_idx)
note_tracks = channel_note_tracks[c]
if track_idx not in note_tracks:
note_tracks.append(track_idx)
new_event[4] = max(1, round(16 * new_event[4] / ticks_per_beat))
elif event[0] == "set_tempo":
if new_event[4] == 0: # invalid tempo
continue
bpm = int(self.tempo2bpm(new_event[4]))
new_event[4] = min(bpm, 255)
if event[0] == "note":
key = tuple(new_event[:4] + new_event[5:-1])
else:
key = tuple(new_event[:-1])
if event[0] == "patch_change":
c, p = event[2:]
if c > 15 or c < 0:
continue
last_p = patch_dict.setdefault(c, None)
if last_p == p:
continue
patch_dict[c] = p
if c not in patch_channels:
patch_channels.append(c)
elif event[0] == "control_change":
c, cc, v = event[2:]
if c > 15 or c < 0:
continue
last_v = control_dict.setdefault((c, cc), 0)
if abs(last_v - v) < cc_eps:
continue
control_dict[(c, cc)] = v
elif event[0] == "set_tempo":
tempo = new_event[-1]
if abs(last_tempo - tempo) < tempo_eps:
continue
last_tempo = tempo
if c != -1:
if c not in channels:
channels.append(c)
tr_map = track_idx_map[c]
if track_idx not in tr_map:
tr_map[track_idx] = 0
if event[0] == "note": # to eliminate note overlap due to quantization
cp = tuple(new_event[5:7])
if cp in last_notes:
last_note_key, last_note = last_notes[cp]
last_t = last_note[1] * 16 + last_note[2]
last_note[4] = max(0, min(last_note[4], t - last_t))
if last_note[4] == 0:
event_list.pop(last_note_key)
last_notes[cp] = (key, new_event)
event_list[key] = new_event
event_list = list(event_list.values())
empty_channels = [c for c in channels if empty_channels[c]]
if remap_track_channel:
patch_channels = []
channels_count = 0
channels_map = {9: 9} if 9 in channels else {}
if remove_empty_channels:
channels = sorted(channels, key=lambda x: 1 if x in empty_channels else 0)
for c in channels:
if c == 9:
continue
channels_map[c] = channels_count
channels_count += 1
if channels_count == 9:
channels_count = 10
channels = list(channels_map.values())
track_count = 0
track_idx_map_order = [k for k, v in sorted(list(channels_map.items()), key=lambda x: x[1])]
for c in track_idx_map_order: # tracks not to remove
if remove_empty_channels and c in empty_channels:
continue
tr_map = track_idx_map[c]
for track_idx in tr_map:
note_tracks = channel_note_tracks[c]
if len(note_tracks) != 0 and track_idx not in note_tracks:
continue
track_count += 1
tr_map[track_idx] = track_count
for c in track_idx_map_order: # tracks to remove
if not (remove_empty_channels and c in empty_channels):
continue
tr_map = track_idx_map[c]
for track_idx in tr_map:
note_tracks = channel_note_tracks[c]
if not (len(note_tracks) != 0 and track_idx not in note_tracks):
continue
track_count += 1
tr_map[track_idx] = track_count
empty_channels = [channels_map[c] for c in empty_channels]
track_idx_dict = {}
for event in event_list:
name = event[0]
track_idx = event[3]
if name == "note":
c = event[5]
event[5] = channels_map[c]
event[3] = track_idx_map[c][track_idx]
track_idx_dict.setdefault(event[5], event[3])
# setdefault, so the track_idx is first of the channel
elif name == "set_tempo":
event[3] = 0
elif name == "control_change" or name == "patch_change":
c = event[4]
event[4] = channels_map[c]
tr_map = track_idx_map[c]
# move the event to first track of the channel if it's original track is empty
note_tracks = channel_note_tracks[c]
if len(note_tracks) != 0 and track_idx not in note_tracks:
track_idx = channel_note_tracks[c][0]
new_track_idx = tr_map[track_idx]
event[3] = new_track_idx
if name == "patch_change" and event[4] not in patch_channels:
patch_channels.append(event[4])
if add_default_instr:
for c in channels:
if c not in patch_channels and c in track_idx_dict:
event_list.append(["patch_change", 0, 0, track_idx_dict[c], c, 0])
events_name_order = {"set_tempo": 0, "patch_change": 1, "control_change": 2, "note": 3}
events_order = lambda e: e[1:4] + [events_name_order[e[0]]]
event_list = sorted(event_list, key=events_order)
setup_events = {}
notes_in_setup = False
for i, event in enumerate(event_list): # optimise setup
new_event = [*event]
if event[0] != "note":
new_event[1] = 0
new_event[2] = 0
has_next = False
has_pre = False
if i < len(event_list) - 1:
next_event = event_list[i + 1]
has_next = event[1] + event[2] == next_event[1] + next_event[2]
if notes_in_setup and i > 0:
pre_event = event_list[i - 1]
has_pre = event[1] + event[2] == pre_event[1] + pre_event[2]
if (event[0] == "note" and not has_next) or (notes_in_setup and not has_pre):
event_list = sorted(setup_events.values(), key=events_order) + event_list[i:]
break
else:
if event[0] == "note":
notes_in_setup = True
key = tuple([event[0]] + event[3:-2])
else:
key = tuple([event[0]] + event[3:-1])
setup_events[key] = new_event
last_t1 = 0
midi_seq = []
for event in event_list:
if remove_empty_channels and event[0] in ["control_change", "patch_change"] and event[4] in empty_channels:
continue
cur_t1 = event[1]
event[1] = event[1] - last_t1
tokens = self.event2tokens(event)
if not tokens:
continue
midi_seq.append(tokens)
last_t1 = cur_t1
if add_bos_eos:
bos = [self.bos_id] + [self.pad_id] * (self.max_token_seq - 1)
eos = [self.eos_id] + [self.pad_id] * (self.max_token_seq - 1)
midi_seq = [bos] + midi_seq + [eos]
return midi_seq
def event2tokens(self, event):
name = event[0]
params = event[1:]
if not all([0 <= params[i] < self.event_parameters[p] for i, p in enumerate(self.events[name])]):
return []
tokens = [self.event_ids[name]] + [self.parameter_ids[p][params[i]]
for i, p in enumerate(self.events[name])]
tokens += [self.pad_id] * (self.max_token_seq - len(tokens))
return tokens
def tokens2event(self, tokens):
if tokens[0] not in self.id_events:
return []
name = self.id_events[tokens[0]]
if len(tokens) <= len(self.events[name]):
return []
params = tokens[1:]
params = [params[i] - self.parameter_ids[p][0] for i, p in enumerate(self.events[name])]
if not all([0 <= params[i] < self.event_parameters[p] for i, p in enumerate(self.events[name])]):
return []
event = [name] + params
return event
def detokenize(self, midi_seq):
ticks_per_beat = 480
tracks_dict = {}
t1 = 0
for tokens in midi_seq:
if tokens[0] in self.id_events:
event = self.tokens2event(tokens)
if not event:
continue
name = event[0]
if name == "set_tempo":
event[4] = self.bpm2tempo(event[4])
if event[0] == "note":
event[4] = int(event[4] * ticks_per_beat / 16)
t1 += event[1]
t = t1 * 16 + event[2]
t = int(t * ticks_per_beat / 16)
track_idx = event[3]
if track_idx not in tracks_dict:
tracks_dict[track_idx] = []
tracks_dict[track_idx].append([event[0], t] + event[4:])
tracks = [tr for idx, tr in sorted(list(tracks_dict.items()), key=lambda it: it[0])]
for i in range(len(tracks)): # to eliminate note overlap
track = tracks[i]
track = sorted(track, key=lambda e: e[1])
last_note_t = {}
zero_len_notes = []
for e in reversed(track):
if e[0] == "note":
t, d, c, p = e[1:5]
key = (c, p)
if key in last_note_t:
d = min(d, max(last_note_t[key] - t, 0))
last_note_t[key] = t
e[2] = d
if d == 0:
zero_len_notes.append(e)
for e in zero_len_notes:
track.remove(e)
tracks[i] = track
return [ticks_per_beat, *tracks]
def midi2img(self, midi_score):
ticks_per_beat = midi_score[0]
notes = []
max_time = 1
track_num = len(midi_score[1:])
for track_idx, track in enumerate(midi_score[1:]):
for event in track:
t = round(16 * event[1] / ticks_per_beat)
if event[0] == "note":
d = max(1, round(16 * event[2] / ticks_per_beat))
c, p = event[3:5]
max_time = max(max_time, t + d + 1)
notes.append((track_idx, c, p, t, d))
img = np.zeros((128, max_time, 3), dtype=np.uint8)
colors = {(i, j): np.random.randint(50, 256, 3) for i in range(track_num) for j in range(16)}
for note in notes:
tr, c, p, t, d = note
img[p, t: t + d] = colors[(tr, c)]
img = PIL.Image.fromarray(np.flip(img, 0))
return img
def augment(self, midi_seq, max_pitch_shift=4, max_vel_shift=10, max_cc_val_shift=10, max_bpm_shift=10,
max_track_shift=0, max_channel_shift=16):
pitch_shift = random.randint(-max_pitch_shift, max_pitch_shift)
vel_shift = random.randint(-max_vel_shift, max_vel_shift)
cc_val_shift = random.randint(-max_cc_val_shift, max_cc_val_shift)
bpm_shift = random.randint(-max_bpm_shift, max_bpm_shift)
track_shift = random.randint(0, max_track_shift)
channel_shift = random.randint(0, max_channel_shift)
midi_seq_new = []
for tokens in midi_seq:
tokens_new = [*tokens]
if tokens[0] in self.id_events:
name = self.id_events[tokens[0]]
for i, pn in enumerate(self.events[name]):
if pn == "track":
tr = tokens[1 + i] - self.parameter_ids[pn][0]
tr += track_shift
tr = tr % self.event_parameters[pn]
tokens_new[1 + i] = self.parameter_ids[pn][tr]
elif pn == "channel":
c = tokens[1 + i] - self.parameter_ids[pn][0]
c0 = c
c += channel_shift
c = c % self.event_parameters[pn]
if c0 == 9:
c = 9
elif c == 9:
c = (9 + channel_shift) % self.event_parameters[pn]
tokens_new[1 + i] = self.parameter_ids[pn][c]
if name == "note":
c = tokens[5] - self.parameter_ids["channel"][0]
p = tokens[6] - self.parameter_ids["pitch"][0]
v = tokens[7] - self.parameter_ids["velocity"][0]
if c != 9: # no shift for drums
p += pitch_shift
if not 0 <= p < 128:
return midi_seq
v += vel_shift
v = max(1, min(127, v))
tokens_new[6] = self.parameter_ids["pitch"][p]
tokens_new[7] = self.parameter_ids["velocity"][v]
elif name == "control_change":
cc = tokens[5] - self.parameter_ids["controller"][0]
val = tokens[6] - self.parameter_ids["value"][0]
if cc in [1, 2, 7, 11]:
val += cc_val_shift
val = max(1, min(127, val))
tokens_new[6] = self.parameter_ids["value"][val]
elif name == "set_tempo":
bpm = tokens[4] - self.parameter_ids["bpm"][0]
bpm += bpm_shift
bpm = max(1, min(255, bpm))
tokens_new[4] = self.parameter_ids["bpm"][bpm]
midi_seq_new.append(tokens_new)
return midi_seq_new
def check_quality(self, midi_seq, alignment_min=0.3, tonality_min=0.8, piano_max=0.7, notes_bandwidth_min=3,
notes_density_max=50, notes_density_min=2.5, total_notes_max=20000, total_notes_min=256,
note_window_size=16):
total_notes = 0
channels = []
time_hist = [0] * 16
note_windows = {}
notes_sametime = []
notes_density_list = []
tonality_list = []
notes_bandwidth_list = []
instruments = {}
piano_channels = []
abs_t1 = 0
last_t = 0
for tsi, tokens in enumerate(midi_seq):
event = self.tokens2event(tokens)
if not event:
continue
t1, t2, tr = event[1:4]
abs_t1 += t1
t = abs_t1 * 16 + t2
c = None
if event[0] == "note":
d, c, p, v = event[4:]
total_notes += 1
time_hist[t2] += 1
if c != 9: # ignore drum channel
if c not in instruments:
instruments[c] = 0
if c not in piano_channels:
piano_channels.append(c)
note_windows.setdefault(abs_t1 // note_window_size, []).append(p)
if last_t != t:
notes_sametime = [(et, p_) for et, p_ in notes_sametime if et > last_t]
notes_sametime_p = [p_ for _, p_ in notes_sametime]
if len(notes_sametime) > 0:
notes_bandwidth_list.append(max(notes_sametime_p) - min(notes_sametime_p))
notes_sametime.append((t + d - 1, p))
elif event[0] == "patch_change":
c, p = event[4:]
instruments[c] = p
if p == 0 and c not in piano_channels:
piano_channels.append(c)
if c is not None and c not in channels:
channels.append(c)
last_t = t
reasons = []
if total_notes < total_notes_min:
reasons.append("total_min")
if total_notes > total_notes_max:
reasons.append("total_max")
if len(note_windows) == 0 and total_notes > 0:
reasons.append("drum_only")
if reasons:
return False, reasons
time_hist = sorted(time_hist, reverse=True)
alignment = sum(time_hist[:2]) / total_notes
for notes in note_windows.values():
key_hist = [0] * 12
for p in notes:
key_hist[p % 12] += 1
key_hist = sorted(key_hist, reverse=True)
tonality_list.append(sum(key_hist[:7]) / len(notes))
notes_density_list.append(len(notes) / note_window_size)
tonality_list = sorted(tonality_list)
tonality = sum(tonality_list) / len(tonality_list)
notes_bandwidth = sum(notes_bandwidth_list) / len(notes_bandwidth_list) if notes_bandwidth_list else 0
notes_density = max(notes_density_list) if notes_density_list else 0
piano_ratio = len(piano_channels) / len(channels)
if len(channels) <= 3: # ignore piano threshold if it is a piano solo midi
piano_max = 1
if alignment < alignment_min: # check weather the notes align to the bars (because some midi files are recorded)
reasons.append("alignment")
if tonality < tonality_min: # check whether the music is tonal
reasons.append("tonality")
if notes_bandwidth < notes_bandwidth_min: # check whether music is melodic line only
reasons.append("bandwidth")
if not notes_density_min < notes_density < notes_density_max:
reasons.append("density")
if piano_ratio > piano_max: # check whether most instruments is piano (because some midi files don't have instruments assigned correctly)
reasons.append("piano")
return not reasons, reasons
class MIDITokenizerV2:
def __init__(self):
self.version = "v2"
self.optimise_midi = False
self.vocab_size = 0
def allocate_ids(size):
ids = [self.vocab_size + i for i in range(size)]
self.vocab_size += size
return ids
self.pad_id = allocate_ids(1)[0]
self.bos_id = allocate_ids(1)[0]
self.eos_id = allocate_ids(1)[0]
self.events = {
"note": ["time1", "time2", "track", "channel", "pitch", "velocity", "duration"],
"patch_change": ["time1", "time2", "track", "channel", "patch"],
"control_change": ["time1", "time2", "track", "channel", "controller", "value"],
"set_tempo": ["time1", "time2", "track", "bpm"],
"time_signature": ["time1", "time2", "track", "nn", "dd"],
"key_signature": ["time1", "time2", "track", "sf", "mi"],
}
self.event_parameters = {
"time1": 128, "time2": 16, "duration": 2048, "track": 128, "channel": 16, "pitch": 128, "velocity": 128,
"patch": 128, "controller": 128, "value": 128, "bpm": 384, "nn": 16, "dd": 4, "sf": 15, "mi": 2
}
self.event_ids = {e: allocate_ids(1)[0] for e in self.events.keys()}
self.id_events = {i: e for e, i in self.event_ids.items()}
self.parameter_ids = {p: allocate_ids(s) for p, s in self.event_parameters.items()}
self.max_token_seq = max([len(ps) for ps in self.events.values()]) + 1
def to_dict(self) -> Dict[str, Any]:
d = {
"version":self.version,
"optimise_midi":self.optimise_midi,
"vocab_size": self.vocab_size,
"events": self.events,
"event_parameters": self.event_parameters,
"max_token_seq": self.max_token_seq,
"pad_id": self.pad_id,
"bos_id": self.bos_id,
"eos_id": self.eos_id,
}
return d
def set_optimise_midi(self, optimise_midi=True):
self.optimise_midi = optimise_midi
@staticmethod
def tempo2bpm(tempo):
tempo = tempo / 10 ** 6 # us to s
bpm = 60 / tempo
return bpm
@staticmethod
def bpm2tempo(bpm):
if bpm == 0:
bpm = 1
tempo = int((60 / bpm) * 10 ** 6)
return tempo
@staticmethod
def sf2key(sf):
# sf in key_signature to key.
# key represents the sequence from C note to B note (12 in total)
return (sf * 7) % 12
@staticmethod
def key2sf(k, mi):
# key to sf
sf = (k * 7) % 12
if sf > 6 or (mi == 1 and sf >= 5):
sf -= 12
return sf
@staticmethod
def detect_key_signature(key_hist, threshold=0.7):
if len(key_hist) != 12:
return None
if sum(key_hist) == 0:
return None
p = sum(sorted(key_hist, reverse=True)[:7]) / sum(key_hist)
if p < threshold:
return None
keys = [x[1] for x in sorted(zip(key_hist, range(len(key_hist))), reverse=True, key=lambda x: x[0])[:7]]
keys = sorted(keys)
semitones = []
for i in range(len(keys)):
dis = keys[i] - keys[i - 1]
if dis == 1 or dis == -11:
semitones.append(keys[i])
if len(semitones) != 2:
return None
semitones_dis = semitones[1] - semitones[0]
if semitones_dis == 5:
root_key = semitones[0]
elif semitones_dis == 7:
root_key = semitones[1]
else:
return None
return root_key
def tokenize(self, midi_score, add_bos_eos=True, cc_eps=4, tempo_eps=4,
remap_track_channel=None, add_default_instr=None, remove_empty_channels=None):
if remap_track_channel is None: # set default value
remap_track_channel = self.optimise_midi
if add_default_instr is None:
add_default_instr = self.optimise_midi
if remove_empty_channels is None:
remove_empty_channels = self.optimise_midi
ticks_per_beat = midi_score[0]
event_list = {}
track_idx_map = {i: dict() for i in range(16)}
track_idx_dict = {}
channels = []
patch_channels = []
empty_channels = [True] * 16
channel_note_tracks = {i: list() for i in range(16)}
note_key_hist = [0]*12
key_sigs = []
track_to_channels = {}
for track_idx, track in enumerate(midi_score[1:129]):
last_notes = {}
patch_dict = {}
control_dict = {}
last_bpm = 0
track_channels = []
track_to_channels.setdefault(track_idx, track_channels)
for event in track:
if event[0] not in self.events:
continue
name = event[0]
c = -1
t = round(16 * event[1] / ticks_per_beat) # quantization
new_event = [name, t // 16, t % 16, track_idx]
if name == "note":
d, c, p, v = event[2:]
if not (0 <= c <= 15):
continue
d = max(1, round(16 * d / ticks_per_beat))
new_event += [c, p, v, d]
empty_channels[c] = False
track_idx_dict.setdefault(c, track_idx)
note_tracks = channel_note_tracks[c]
if track_idx not in note_tracks:
note_tracks.append(track_idx)
if c != 9:
note_key_hist[p%12] += 1
if c not in track_channels:
track_channels.append(c)
elif name == "patch_change":
c, p = event[2:]
if not (0 <= c <= 15):
continue
new_event += [c, p]
last_p = patch_dict.setdefault(c, None)
if last_p == p:
continue
patch_dict[c] = p
if c not in patch_channels:
patch_channels.append(c)
elif name == "control_change":
c, cc, v = event[2:]
if not (0 <= c <= 15):
continue
new_event += [c, cc, v]
last_v = control_dict.setdefault((c, cc), 0)
if abs(last_v - v) < cc_eps:
continue
control_dict[(c, cc)] = v
elif name == "set_tempo":
tempo = event[2]
if tempo == 0: # invalid tempo
continue
bpm = min(int(self.tempo2bpm(tempo)), 383)
new_event += [bpm]
if abs(last_bpm - bpm) < tempo_eps:
continue
last_bpm = bpm
elif name == "time_signature":
nn, dd = event[2:4]
if not (1 <= nn <= 16 and 1 <= dd <= 4): # invalid
continue
nn -= 1 # make it start from 0
dd -= 1
new_event += [nn, dd]
elif name == "key_signature":
sf, mi = event[2:]
if not (-7 <= sf <= 7 and 0 <= mi <= 1): # invalid
continue
sf += 7
new_event += [sf, mi]
key_sigs.append(new_event)
if name in ["note", "time_signature", "key_signature"]:
key = tuple(new_event[:-2])
else:
key = tuple(new_event[:-1])
if c != -1:
if c not in channels:
channels.append(c)
tr_map = track_idx_map[c]
if track_idx not in tr_map:
tr_map[track_idx] = 0
if event[0] == "note": # to eliminate note overlap due to quantization
cp = tuple(new_event[4:6]) # channel pitch
if cp in last_notes:
last_note_key, last_note = last_notes[cp]
last_t = last_note[1] * 16 + last_note[2]
last_note[-1] = max(0, min(last_note[-1], t - last_t)) # modify duration
if last_note[-1] == 0:
event_list.pop(last_note_key)
last_notes[cp] = (key, new_event)
event_list[key] = new_event
event_list = list(event_list.values())
empty_channels = [c for c in channels if empty_channels[c]]
if remap_track_channel:
patch_channels = []
channels_count = 0
channels_map = {9: 9} if 9 in channels else {}
if remove_empty_channels:
channels = sorted(channels, key=lambda x: 1 if x in empty_channels else 0)
for c in channels:
if c == 9:
continue
channels_map[c] = channels_count
channels_count += 1
if channels_count == 9:
channels_count = 10
channels = list(channels_map.values())
track_count = 0
track_idx_map_order = [k for k, v in sorted(list(channels_map.items()), key=lambda x: x[1])]
for c in track_idx_map_order: # tracks not to remove
if remove_empty_channels and c in empty_channels:
continue
tr_map = track_idx_map[c]
for track_idx in tr_map:
note_tracks = channel_note_tracks[c]
if len(note_tracks) != 0 and track_idx not in note_tracks:
continue
track_count += 1
tr_map[track_idx] = track_count
for c in track_idx_map_order: # tracks to remove
if not (remove_empty_channels and c in empty_channels):
continue
tr_map = track_idx_map[c]
for track_idx in tr_map:
note_tracks = channel_note_tracks[c]
if not (len(note_tracks) != 0 and track_idx not in note_tracks):
continue
track_count += 1
tr_map[track_idx] = track_count
empty_channels = [channels_map[c] for c in empty_channels]
track_idx_dict = {}
key_sigs = []
key_signature_to_add = []
key_signature_to_remove = []
for event in event_list:
name = event[0]
track_idx = event[3]
if name == "note":
c = event[4]
event[4] = channels_map[c] # channel
event[3] = track_idx_map[c][track_idx] # track
track_idx_dict.setdefault(event[4], event[3])
# setdefault, so the track_idx is first of the channel
elif name in ["set_tempo", "time_signature"]:
event[3] = 0 # set track 0 for meta events
elif name == "key_signature":
new_channel_track_idxs = []
for c, tr_map in track_idx_map.items():
if track_idx in tr_map:
new_track_idx = tr_map[track_idx]
c = channels_map[c]
new_channel_track_idx = (c, new_track_idx)
if new_track_idx == 0:
continue
if new_channel_track_idx not in new_channel_track_idxs:
new_channel_track_idxs.append(new_channel_track_idx)
if len(new_channel_track_idxs) == 0:
if event[3] == 0: # keep key_signature on track 0 (meta)
key_sigs.append(event)
continue
event[3] = -1 # avoid remove same event
key_signature_to_remove.append(event) # empty track
continue
c, nt = new_channel_track_idxs[0]
event[3] = nt
key_sigs.append(event)
if c == 9:
event[4] = 7 # sf=0
for c, nt in new_channel_track_idxs[1:]:
new_event = [*event]
new_event[3] = nt
if c == 9:
new_event[4] = 7 # sf=0
key_sigs.append(new_event)
key_signature_to_add.append(new_event)
elif name == "control_change" or name == "patch_change":
c = event[4]
event[4] = channels_map[c] # channel
tr_map = track_idx_map[c]
# move the event to first track of the channel if it's original track is empty
note_tracks = channel_note_tracks[c]
if len(note_tracks) != 0 and track_idx not in note_tracks:
track_idx = channel_note_tracks[c][0]
new_track_idx = tr_map[track_idx]
event[3] = new_track_idx
if name == "patch_change" and event[4] not in patch_channels:
patch_channels.append(event[4])
for key_sig in key_signature_to_remove:
event_list.remove(key_sig)
event_list += key_signature_to_add
track_to_channels ={}
for c, tr_map in track_idx_map.items():
if c not in channels_map:
continue
c = channels_map[c]
for _, track_idx in tr_map.items():
track_to_channels.setdefault(track_idx, [])
cs = track_to_channels[track_idx]
if c not in cs:
cs.append(c)
if add_default_instr:
for c in channels:
if c not in patch_channels and c in track_idx_dict:
event_list.append(["patch_change", 0, 0, track_idx_dict[c], c, 0])
if len(key_sigs) == 0 or all([key_sig[4]==7 for key_sig in key_sigs]):
# detect key signature or fix the default key signature
root_key = self.detect_key_signature(note_key_hist)
if root_key is not None:
sf = self.key2sf(root_key, 0)
# print("detect_key_signature",sf)
if len(key_sigs) == 0:
for tr, cs in track_to_channels.items():
if remap_track_channel and tr == 0:
continue
new_event = ["key_signature", 0, 0, tr, (0 if (len(cs) == 1 and cs[0] == 9) else sf) + 7, 0]
event_list.append(new_event)
else:
for key_sig in key_sigs:
tr = key_sig[3]
if tr in track_to_channels:
cs = track_to_channels[tr]
if len(cs) == 1 and cs[0] == 9:
continue
key_sig[4] = sf + 7
key_sig[5] = 0
else:
# remove default key signature
for key_sig in key_sigs:
event_list.remove(key_sig)
events_name_order = ["time_signature", "key_signature", "set_tempo", "patch_change", "control_change", "note"]
events_name_order = {name: i for i, name in enumerate(events_name_order)}
events_order = lambda e: e[1:4] + [events_name_order[e[0]]]
event_list = sorted(event_list, key=events_order)
setup_events = {}
notes_in_setup = False
for i, event in enumerate(event_list): # optimise setup
new_event = [*event] # make copy of event
if event[0] not in ["note", "time_signature"]:
new_event[1] = 0
new_event[2] = 0
has_next = False
has_pre = False
if i < len(event_list) - 1:
next_event = event_list[i + 1]
has_next = event[1] + event[2] == next_event[1] + next_event[2]
if notes_in_setup and i > 0:
pre_event = event_list[i - 1]
has_pre = event[1] + event[2] == pre_event[1] + pre_event[2]
if (event[0] == "note" and not has_next) or (notes_in_setup and not has_pre):
event_list = sorted(setup_events.values(), key=events_order) + event_list[i:]
break
else:
if event[0] == "note":
notes_in_setup = True
if event[0] in ["note", "time_signature", "key_signature"]:
key = tuple([event[0]]+event[3:-2])
else:
key = tuple([event[0]]+event[3:-1])
setup_events[key] = new_event
last_t1 = 0
midi_seq = []
for event in event_list:
if remove_empty_channels and event[0] in ["control_change", "patch_change"] and event[4] in empty_channels:
continue
cur_t1 = event[1]
event[1] = event[1] - last_t1
tokens = self.event2tokens(event)
if not tokens:
continue
midi_seq.append(tokens)
last_t1 = cur_t1
if add_bos_eos:
bos = [self.bos_id] + [self.pad_id] * (self.max_token_seq - 1)
eos = [self.eos_id] + [self.pad_id] * (self.max_token_seq - 1)
midi_seq = [bos] + midi_seq + [eos]
return midi_seq
def event2tokens(self, event):
name = event[0]
params = event[1:]
if not all([0 <= params[i] < self.event_parameters[p] for i, p in enumerate(self.events[name])]):
return []
tokens = [self.event_ids[name]] + [self.parameter_ids[p][params[i]]
for i, p in enumerate(self.events[name])]
tokens += [self.pad_id] * (self.max_token_seq - len(tokens))
return tokens
def tokens2event(self, tokens):
if tokens[0] not in self.id_events:
return []
name = self.id_events[tokens[0]]
if len(tokens) <= len(self.events[name]):
return []
params = tokens[1:]
params = [params[i] - self.parameter_ids[p][0] for i, p in enumerate(self.events[name])]
if not all([0 <= params[i] < self.event_parameters[p] for i, p in enumerate(self.events[name])]):
return []
event = [name] + params
return event
def detokenize(self, midi_seq):
ticks_per_beat = 480
tracks_dict = {}
t1 = 0
for tokens in midi_seq:
if tokens[0] in self.id_events:
event = self.tokens2event(tokens)
if not event:
continue
name = event[0]
t1 += event[1]
t = t1 * 16 + event[2]
t = int(t * ticks_per_beat / 16)
track_idx = event[3]
event_new = [name, t]
if name == "note":
c, p, v, d = event[4:]
d = int(d * ticks_per_beat / 16)
event_new += [d, c, p, v]
elif name == "control_change" or name == "patch_change":
event_new += event[4:]
elif name == "set_tempo":
event_new += [self.bpm2tempo(event[4])]
elif name == "time_signature":
nn, dd = event[4:]
nn += 1
dd += 1
event_new += [nn, dd, 24, 8] # usually cc, bb = 24, 8
elif name == "key_signature":
sf, mi = event[4:]
sf -= 7
event_new += [sf, mi]
else: # should not go here
continue
if track_idx not in tracks_dict:
tracks_dict[track_idx] = []
tracks_dict[track_idx].append(event_new)
tracks = [tr for idx, tr in sorted(list(tracks_dict.items()), key=lambda it: it[0])]
for i in range(len(tracks)): # to eliminate note overlap
track = tracks[i]
track = sorted(track, key=lambda e: e[1])
last_note_t = {}
zero_len_notes = []
for e in reversed(track):
if e[0] == "note":
t, d, c, p = e[1:5]
key = (c, p)
if key in last_note_t:
d = min(d, max(last_note_t[key] - t, 0))
last_note_t[key] = t
e[2] = d
if d == 0:
zero_len_notes.append(e)
for e in zero_len_notes:
track.remove(e)
tracks[i] = track
return [ticks_per_beat, *tracks]
def midi2img(self, midi_score):
ticks_per_beat = midi_score[0]
notes = []
max_time = 1
track_num = len(midi_score[1:])
for track_idx, track in enumerate(midi_score[1:]):
for event in track:
t = round(16 * event[1] / ticks_per_beat)
if event[0] == "note":
d = max(1, round(16 * event[2] / ticks_per_beat))
c, p = event[3:5]
max_time = max(max_time, t + d + 1)
notes.append((track_idx, c, p, t, d))
img = np.zeros((128, max_time, 3), dtype=np.uint8)
colors = {(i, j): np.random.randint(50, 256, 3) for i in range(track_num) for j in range(16)}
for note in notes:
tr, c, p, t, d = note
img[p, t: t + d] = colors[(tr, c)]
img = PIL.Image.fromarray(np.flip(img, 0))
return img
def augment(self, midi_seq, max_pitch_shift=4, max_vel_shift=10, max_cc_val_shift=10, max_bpm_shift=10,
max_track_shift=0, max_channel_shift=16):
pitch_shift = random.randint(-max_pitch_shift, max_pitch_shift)
vel_shift = random.randint(-max_vel_shift, max_vel_shift)
cc_val_shift = random.randint(-max_cc_val_shift, max_cc_val_shift)
bpm_shift = random.randint(-max_bpm_shift, max_bpm_shift)
track_shift = random.randint(0, max_track_shift)
channel_shift = random.randint(0, max_channel_shift)
midi_seq_new = []
key_signature_tokens = []
track_to_channels = {}
for tokens in midi_seq:
tokens_new = [*tokens]
if tokens[0] in self.id_events:
name = self.id_events[tokens[0]]
for i, pn in enumerate(self.events[name]):
if pn == "track":
tr = tokens[1 + i] - self.parameter_ids[pn][0]
tr += track_shift
tr = tr % self.event_parameters[pn]
tokens_new[1 + i] = self.parameter_ids[pn][tr]
elif pn == "channel":
c = tokens[1 + i] - self.parameter_ids[pn][0]
c0 = c
c += channel_shift
c = c % self.event_parameters[pn]
if c0 == 9:
c = 9
elif c == 9:
c = (9 + channel_shift) % self.event_parameters[pn]
tokens_new[1 + i] = self.parameter_ids[pn][c]
if name == "note":
tr = tokens[3] - self.parameter_ids["track"][0]
c = tokens[4] - self.parameter_ids["channel"][0]
p = tokens[5] - self.parameter_ids["pitch"][0]
v = tokens[6] - self.parameter_ids["velocity"][0]
if c != 9: # no shift for drums
p += pitch_shift
if not 0 <= p < 128:
return midi_seq
v += vel_shift
v = max(1, min(127, v))
tokens_new[5] = self.parameter_ids["pitch"][p]
tokens_new[6] = self.parameter_ids["velocity"][v]
track_to_channels.setdefault(tr, [])
cs = track_to_channels[tr]
if c not in cs:
cs.append(c)
elif name == "control_change":
cc = tokens[5] - self.parameter_ids["controller"][0]
val = tokens[6] - self.parameter_ids["value"][0]
if cc in [1, 2, 7, 11]:
val += cc_val_shift
val = max(1, min(127, val))
tokens_new[6] = self.parameter_ids["value"][val]
elif name == "set_tempo":
bpm = tokens[4] - self.parameter_ids["bpm"][0]
bpm += bpm_shift
bpm = max(1, min(383, bpm))
tokens_new[4] = self.parameter_ids["bpm"][bpm]
elif name == "key_signature":
sf = tokens[4] - self.parameter_ids["sf"][0]
mi = tokens[5] - self.parameter_ids["mi"][0]
sf -= 7
k = self.sf2key(sf)
k = (k + pitch_shift) % 12
sf = self.key2sf(k, mi)
sf += 7
tokens_new[4] = self.parameter_ids["sf"][sf]
tokens_new[5] = self.parameter_ids["mi"][mi]
key_signature_tokens.append(tokens_new)
midi_seq_new.append(tokens_new)
for tokens in key_signature_tokens:
tr = tokens[3] - self.parameter_ids["track"][0]
if tr in track_to_channels:
cs = track_to_channels[tr]
if len(cs) == 1 and cs[0] == 9:
tokens[4] = self.parameter_ids["sf"][7] # sf=0
return midi_seq_new
def check_quality(self, midi_seq, alignment_min=0.3, tonality_min=0.8, piano_max=0.7, notes_bandwidth_min=3,
notes_density_max=50, notes_density_min=2.5, total_notes_max=20000, total_notes_min=256,
note_window_size=16):
total_notes = 0
channels = []
time_hist = [0] * 16
note_windows = {}
notes_sametime = []
notes_density_list = []
tonality_list = []
notes_bandwidth_list = []
instruments = {}
piano_channels = []
abs_t1 = 0
last_t = 0
for tsi, tokens in enumerate(midi_seq):
event = self.tokens2event(tokens)
if not event:
continue
t1, t2, tr = event[1:4]
abs_t1 += t1
t = abs_t1 * 16 + t2
c = None
if event[0] == "note":
c, p, v, d = event[4:]
total_notes += 1
time_hist[t2] += 1
if c != 9: # ignore drum channel
if c not in instruments:
instruments[c] = 0
if c not in piano_channels:
piano_channels.append(c)
note_windows.setdefault(abs_t1 // note_window_size, []).append(p)
if last_t != t:
notes_sametime = [(et, p_) for et, p_ in notes_sametime if et > last_t]
notes_sametime_p = [p_ for _, p_ in notes_sametime]
if len(notes_sametime) > 0:
notes_bandwidth_list.append(max(notes_sametime_p) - min(notes_sametime_p))
notes_sametime.append((t + d - 1, p))
elif event[0] == "patch_change":
c, p = event[4:]
instruments[c] = p
if p == 0 and c not in piano_channels:
piano_channels.append(c)
if c is not None and c not in channels:
channels.append(c)
last_t = t
reasons = []
if total_notes < total_notes_min:
reasons.append("total_min")
if total_notes > total_notes_max:
reasons.append("total_max")
if len(note_windows) == 0 and total_notes > 0:
reasons.append("drum_only")
if reasons:
return False, reasons
time_hist = sorted(time_hist, reverse=True)
alignment = sum(time_hist[:2]) / total_notes
for notes in note_windows.values():
key_hist = [0] * 12
for p in notes:
key_hist[p % 12] += 1
key_hist = sorted(key_hist, reverse=True)
tonality_list.append(sum(key_hist[:7]) / len(notes))
notes_density_list.append(len(notes) / note_window_size)
tonality_list = sorted(tonality_list)
tonality = sum(tonality_list) / len(tonality_list)
notes_bandwidth = sum(notes_bandwidth_list) / len(notes_bandwidth_list) if notes_bandwidth_list else 0
notes_density = max(notes_density_list) if notes_density_list else 0
piano_ratio = len(piano_channels) / len(channels)
if len(channels) <= 3: # ignore piano threshold if it is a piano solo midi
piano_max = 1
if alignment < alignment_min: # check weather the notes align to the bars (because some midi files are recorded)
reasons.append("alignment")
if tonality < tonality_min: # check whether the music is tonal
reasons.append("tonality")
if notes_bandwidth < notes_bandwidth_min: # check whether music is melodic line only
reasons.append("bandwidth")
if not notes_density_min < notes_density < notes_density_max:
reasons.append("density")
if piano_ratio > piano_max: # check whether most instruments is piano (because some midi files don't have instruments assigned correctly)
reasons.append("piano")
return not reasons, reasons
class MIDITokenizer:
def __new__(cls, version="v2"):
if version == "v1":
return MIDITokenizerV1()
elif version == "v2":
return MIDITokenizerV2()
else:
raise ValueError(f"Unsupported version: {version}")