Librosa 0.8.0 | Vocal separation output works, but is sped up to 200% speed

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I am working on this script in python to separate vocals from a track and write it to a music file. I have chosen librosa as a library for this. Here is the code:

import numpy as np
import librosa.display
import soundfile as sf
import matplotlib.pyplot as plt
import librosa

y, sr = librosa.load('testInput.mp3')
output_file_path = "testOutput.wav"

S_full, phase = librosa.magphase(librosa.stft(y))
S_filter = librosa.decompose.nn_filter(S_full,
                                       aggregate=np.median,
                                       metric='cosine',
                                       width=int(librosa.time_to_frames(2, sr=sr)))
S_filter = np.minimum(S_full, S_filter)
margin_i, margin_v = 2, 10
power = 2

mask_i = librosa.util.softmask(S_filter,
                               margin_i * (S_full - S_filter),
                               power=power)

mask_v = librosa.util.softmask(S_full - S_filter,
                               margin_v * S_filter,
                               power=power)

# Once we have the masks, simply multiply them with the input spectrum
# to separate the components
S_foreground = mask_v * S_full
S_background = mask_i * S_full
D_foreground = S_foreground * phase
y_foreground = librosa.istft(D_foreground)
sf.write(output_file_path, y_foreground, samplerate=44100, subtype='PCM_24')

It works somewhat, however the output is sped up to 200%, which also results in the voice being pitched up a lot. Whatever the input is, the output will sound alvin and the chipmunks alike. Does anyone have an idea how to fix this, or what i am doing wrong?

librosa audio python
1 Answers

librosa.load will by default resample to 22050 Hz. To preserve the original sampelrate of the input, use librosa.load(..., sr=None). However note that many parameters in librosa are tuned for 22050 Hz, like FFT lengths etc. In this example the stft and istft, at least.

So you may also want to try keeping that samplerate. In either case it would be good to use samplerate=sr in your call to sf.write() to avoid hardcoding it.

user_19675710
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