我试图将原始wav文件拉伸k倍。在下面的代码中，我使用stretch_factor=2，但理论上我希望这里有任何k。我的问题是output.wav没有被拉伸，甚至音频现在也很混乱。它不适用于k〈1的情况，我试图压缩音频

import numpy as np
from scipy.io import wavfile

sampling_rate, signal = wavfile.read("test.wav")

NFFT = 1024
overlap_factor = 4
stretch_factor = 2

hop_size = int(NFFT / overlap_factor)
num_hops = int(np.ceil(float(len(signal)) / hop_size))
pad_size = num_hops * hop_size - len(signal)
z = np.zeros((pad_size,))
pad_signal = np.concatenate((signal, z))

frames = np.array_split(pad_signal, num_hops)

output = np.zeros((0,), dtype=np.float32)
previous_phase = np.zeros((NFFT,), dtype=np.float32)
summed_phase = np.zeros((NFFT,), dtype=np.float32)

for i, frame in enumerate(frames):
    spectrum = np.fft.fft(frame, n=NFFT)
    magnitude = np.abs(spectrum)
    phase = np.angle(spectrum)
    
    frequencies = np.fft.fftfreq(NFFT, d=1.0/sampling_rate)
    frequencies = np.repeat(frequencies, stretch_factor)
    phase_diff = (frequencies[1] - frequencies[0]) * hop_size / sampling_rate

    expected_phase = previous_phase + phase_diff * 2 * np.pi
    delta_phase = phase - expected_phase

    previous_phase = phase.copy()
    summed_phase += delta_phase
    phase_advances = hop_size * summed_phase / (2 * np.pi)
    phase_advances = np.round(phase_advances).astype(int)

    new_spectrum = np.zeros((NFFT,), dtype=np.complex64)
    for j in range(NFFT):
        j2 = j + phase_advances[j]
        if j2 >= 0 and j2 < NFFT:
            new_spectrum[j2] += spectrum[j]
    new_frame = np.fft.ifft(new_spectrum).real

    output = np.concatenate((output, new_frame[:hop_size]))

wavfile.write("output.wav", sampling_rate, output.astype(np.int16))

这是我第三次重写代码，这是第一次，当它终于做的东西没有错误。我是新的工作与音频，所以不知道该怎么做