A envelope detection to downsample and clean audio data

preprocess.py

def envelope(y, rate, threshold):
    mask = []
    y = pd.Series(y).apply(np.abs)
    y_mean = y.rolling(window=int(rate/10), min_periods=1, center=True).mean()
    for mean in y_mean:
        if mean > threshold:
            mask.append(True)
        else:
            mask.append(False)
    return mask

if len(os.listdir('clean')) == 0:
    for f in tqdm(df.fname):
        signal, rate = librosa.load('wavfiles/'+f, sr=16000)
        mask = envelope(signal, rate, 0.0005)
        wavfile.write(filename='clean/'+f, rate=rate, data=signal[mask])