我编写了一个接收 MIDI 文件的程序，然后使用 Mido，它通过删除特定类型的元数据、重复消息等来清理数据。它还计算了累积时间（因为每个 midi 消息中的时间都是 delta时间）。然后使用它创建一个新的 mido 文件（从头开始），我将所有这些消息附加到一个轨道中（因此基本上轨道被合并）并按累积时间对它们进行排序。然后相应地调整增量时间（请记住，每个新的 midi 轨道从累积时间 0 开始）。我意识到这可能看起来毫无意义（因为我试图构建更干净的同一首歌曲），但目的是拥有更好的数据然后做其他事情。
我已将我的代码分成两部分。第一个执行所有过滤并构造一个大列表，其中每个子列表中的第一项是消息本身，每个子列表中的第二项是累积时间（如上所述，这是按累积时间排序的）。代码的第二部分调整此列表中每个项目的增量时间，然后将列表中的所有消息按顺序（具有更正的增量时间）附加到从头开始创建的轨道上。然后它使用 pygame 播放该曲目。
我似乎遇到的主要问题是时间/节奏。重建的曲目似乎播放得太快或太慢。在某些文件（例如 Bohemian Rhapsody 文件）的情况下，乐器部分也似乎是分离和混乱的。
这是解构和列表构建代码：
import mido
import pygame
all_mid = ['major-scale.mid']
# check is midi file is type 2 (and removes if so) - this is unlikely but can happen on old sites
def remove_type_2(midi):
return True if midi.type == 2 else False
# removes unnecessary meta data types
def filter_meta_type(msg):
accept = ["set_tempo", "time_signature", "key_signature"]
return True if msg.type in accept else False
# removes tempo duplicates and only keeps the last tempo stated for a particular cumulative time
def remove_extra_tempo(msg, msgwithtempos, current_time):
if not msgwithtempos: # if the list is empty
msgwithtempos.append([msg, current_time])
else:
for i in range(len(msgwithtempos)):
msgwithtempo = msgwithtempos[i]
if msgwithtempo[1] == current_time: # this checks duplicates
msgwithtempos.remove(msgwithtempo)
msgwithtempos.append([msg, current_time])
return msgwithtempos
def do_shit(mid, all_messages): # for each track (then message) do the following
msgwithtempos = []
for i, track in enumerate(mid.tracks):
current_time = 0
print(f"Track {i}: {track.name}")
for msg in track:
current_time += msg.time
if msg.type == "sysex data":
pass
elif msg.is_meta:
if filter_meta_type(msg):
if msg.type == "set_tempo":
msgwithtempos = remove_extra_tempo(msg, msgwithtempos, current_time)
else:
all_messages.append([msg, current_time])
else:
all_messages.append([msg, current_time])
return all_messages, msgwithtempos
def main(): # for each midi file do the following
all_lists = []
for i in range(0, len(all_mid)):
all_messages = []
mid = mido.MidiFile(all_mid[i])
if not remove_type_2(mid):
all_messages, msgwithtempos = do_shit(mid, all_messages)
final_messages = all_messages + msgwithtempos
final_messages = sorted(final_messages, key=lambda x: x[1])
all_lists.append(final_messages)
print(all_lists)
return all_lists
if __name__ == '__main__':
main()
这是重构代码：
import mido
import pygame
import regulate_tracks
def play_with_pygame(song):
pygame.init()
pygame.mixer.music.load(song)
length = pygame.time.get_ticks()
pygame.mixer.music.play()
while pygame.mixer.music.get_busy():
pygame.time.wait(length)
def printmessages(mid):
for i, track in enumerate(mid.tracks):
print(f"Track {i}: {track.name}")
for msg in track:
print(msg)
def main():
# get the list of midi files from regulate_tracks
output = regulate_tracks.main()
list1 = output[0]
# create a blank midi file and add a track to it
mid = mido.MidiFile()
track = mido.MidiTrack()
mid.tracks.append(track)
for i in range(len(list1)):
message = list1[i][0]
print(message.type)
if i == 0:
message.time = 0
else:
message.time = list1[i][1] - list1[i - 1][1]
print(message)
track.append(message)
mid.save('new_song.mid')
printmessages(mid)
play_with_pygame('new_song.mid')
if __name__ == '__main__':
main()
示例文件：
波西米亚狂想曲：https ://bitmidi.com/queen-bohemian-rhapsody-mid
河流在你心中流淌：http ://midicollection.net/songs/index.php?id=13
谢谢
编辑：
这似乎是空白 MIDI 创建和附加的问题，因为我创建了此代码，该代码手动复制了短 MIDI 文件中的消息，并且在播放时它们仍然听起来错误（较慢）。
import mido
import pygame
def play_with_pygame(song):
pygame.init()
pygame.mixer.music.load(song)
length = pygame.time.get_ticks()
pygame.mixer.music.play()
while pygame.mixer.music.get_busy():
pygame.time.wait(length)
def main():
mid = mido.MidiFile()
track = mido.MidiTrack()
mid.tracks.append(track)
track.append(mido.MetaMessage('set_tempo', tempo=500000, time=3840))
track.append(mido.MetaMessage('end_of_track', time=0))
track = mido.MidiTrack()
mid.tracks.append(track)
track.append(mido.Message('note_on', channel=0, note=60, velocity=100, time=0))
track.append(mido.Message('note_on', channel=0, note=62, velocity=100, time=960))
track.append(mido.Message('note_on', channel=0, note=64, velocity=100, time=960))
track.append(mido.Message('note_on', channel=0, note=65, velocity=100, time=960))
track.append(mido.Message('program_change', channel=0, program=123, time=960))
track.append(mido.Message('note_on', channel=0, note=67, velocity=100, time=0))
track.append(mido.Message('note_on', channel=0, note=69, velocity=100, time=960))
track.append(mido.Message('note_on', channel=0, note=71, velocity=100, time=960))
track.append(mido.Message('note_on', channel=0, note=72, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=60, velocity=100, time=2880))
track.append(mido.Message('note_off', channel=0, note=62, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=64, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=65, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=67, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=69, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=71, velocity=100, time=960))
track.append(mido.Message('note_off', channel=0, note=72, velocity=100, time=960))
track.append(mido.MetaMessage('end_of_track', time=0))
mid.save('new_song.mid')
play_with_pygame('new_song.mid')
if __name__ == '__main__':
main()