如何在 midi 中将小节数转换为时间？ （音乐）

Question

给定一个 midi 文件，如何将小节计数转换为时间？ 通常，如何轻松地将小节数（整数）映射到歌曲中的时间（以秒为单位）

Answer 1

使用 pretty midi，我的解决方案

import pretty_midi as pm

def get_bar_to_time_dict(self,song,id):
    def get_numerator_for_sig_change(signature_change,id):
        # since sometime pretty midi count are wierd
        if int(signature_change.numerator)==6 and int(signature_change.denominator)==8:
            # 6/8 goes to 2 for sure
            return 2
        return signature_change.numerator
    # we have to take into account time-signature-changes
    changes = song.time_signature_changes
    beats = song.get_beats()
    bar_to_time_dict = dict()
    # first bar is on first position
    current_beat_index = 0
    current_bar = 1
    bar_to_time_dict[current_bar] = beats[current_beat_index]
    for index_time_sig, _ in enumerate(changes):
        numerator = get_numerator_for_sig_change(changes[index_time_sig],id)
        # keep adding to dictionary until the time signature changes, or we are in the last change, in that case iterate till end of beats
        while index_time_sig == len(changes) - 1 or beats[current_beat_index] < changes[index_time_sig + 1].time:
            # we have to increase in numerator steps, minus 1 for counting logic of natural counting
            current_beat_index += numerator
            if current_beat_index > len(beats) - 1:
                # we labeled all beats so end function
                return bar_to_time_dict
            current_bar += 1
            bar_to_time_dict[current_bar] = beats[current_beat_index]
    return bar_to_time_dict

song = pm.PrettyMIDI('some_midi_file.midi')
get_bar_to_time_dict(song)

如果有人知道 pretty midi 或 music21 中解决相同问题的功能，请告诉我，找不到。 编辑：6/8 节拍也有问题，我认为这涵盖了所有边缘情况（不是 100% 确定）