拍の位置を考慮してトラックを断片化する

beatseg.py

import itertools
import os
import shutil
import soundfile as sf
import librosa
import librosa.beat
import librosa.effects

beat = 4

with open("01. What An Amazing Swing.wav", "rb") as fp:
    data, samplerate = sf.read(fp)
x = data.transpose((1, 0))
print(f"{x.dtype=}", f"{x.shape=}", f"{samplerate=}Hz")

y, (start, end) = librosa.effects.trim(x)
mono = librosa.to_mono(y)
tempo, beats = librosa.beat.beat_track(y=mono, sr=samplerate, units="samples")

shutil.rmtree("segments", ignore_errors=True)
os.makedirs("segments", exist_ok=True)

bs = list(map(int, beats))
ts = [0] + [(l + r) // 2 for l, r in zip(bs, bs[1:])]
ss = [t[0] for t in itertools.batched(ts, n=beat)]
xs = list(zip(ss, ss[1:] + [len(mono)]))
kn = len(str(len(xs) + 1))
ops = {"subtype": "PCM_24"}
sf.write(f"segments/a-{0:0{kn}}-start.wav", data[:start], samplerate, **ops)
for i, (l, r) in enumerate(xs, 1):
    print(l, r)
    fr = y[:, l:r]
    sf.write(f"segments/a-{i:0{kn}}.wav", fr.transpose((1, 0)), samplerate, **ops)
sf.write(f"segments/a-{i + 1:0{kn}}-end.wav", data[end:], samplerate, **ops)