adding MIDI chords at specific MetaMessage time

问题

I have a MIDI file with marker as meta-messages.

fname = "avm.mid"
mid = MidiFile(fname) # input file of type 0
metas = [m for m in mid.tracks[0] if m.is_meta]

I have stored the meta marker times in the list "chordTimes". The first maker ( chord position) does not start at 0. I make a new MIDI file:

mo = MidiFile(type =1)# output file
track = MidiTrack()

Now I read through my list of desired chords and and add them to a new track to be added to mo.

for i in range(0, len(chords)-1): 
    chordInfo = chordMidiNotes(chords[i], extraBass= False)
    chordNotes = chordInfo[0]
    # append to track note on messages
    if i != 0:
        for note_value in chordNotes: # result has chord notes
            track.append(Message('note_on', note=note_value, velocity=100, time=0))
    else: 
        for j,note_value in enumerate(chordNotes): # result has chord notes
            if j == 0:
                track.append(Message('note_on', note=note_value, velocity=100, time=chordTimes[0])) 
            else: 
                track.append(Message('note_on', note=note_value, velocity=100, time=0))
    # append to track note off messages
    for k,note_value in enumerate(chordNotes): # result has chord notes
        if k == 0:
            track.append(Message('note_off', note=note_value, velocity=127, time=chordTimes[i+1]))
        else: 
            track.append(Message('note_off', note=note_value, velocity=127, time=0))

# now adding track to output file
mo.tracks.append(mid.tracks[0])
mo.tracks.append(track)

mo.save("songWithChords.mid") 

But when I display it, the chords seem to be incorrect and in the wrong position and look much longer ( about 3 times) than the original one. I checked the header chunk of the output:

<meta message time_signature numerator=4 denominator=4 clocks_per_click=24 notated_32nd_notes_per_beat=8 time=0>, 

Any help would be greatly appreciated.

来源：https://stackoverflow.com/questions/61305523/adding-midi-chords-at-specific-metamessage-time