Difference in spectrogram implementation compared to the paper - potential degradation about visqol HOT 5 CLOSED

import librosa
import librosa.display
import numpy as np
from gammatone.filters import centre_freqs, make_erb_filters

# from src/visqol_manager.cc
kNumBandsAudio = 32
kMinimumFreq = 50
kOverlap = 0.25
# from src/include/analysis_window.h
window_duration = 0.08

# compare src/equivalent_rectangular_bandwidth.cc to function make_erb_filters()
# they use the same constants and have similar logic, and seem based on 
# code written by Malcolm Slaney on June 11, 1998, including dividing the order-8 filter into 4 order-2 sections

fs = 48000
window_duration_samples = int(fs * window_duration)
hop_length_samples = int(fs * window_duration*kOverlap)

# python logic uses max frequency of fs / 2, exactly like in src/gammatone_spectrogram_builder.cc line 41
erb_frequencies = centre_freqs(fs, kNumBandsAudio, kMinimumFreq)
gammatone_filters = make_erb_filters(fs, erb_frequencies)


audio, _ = librosa.load(librosa.example('trumpet', hq=True), sr=fs)
# let's look at only 1 second
audio = audio[:fs]

windowed_audio = librosa.util.frame(audio, window_duration_samples, hop_length_samples)
# shape of windowed_audio is now (3840, 47) - 47 windows of 80ms overlapping by 75%

# for comparison's sake - we'll also use a window function
window = np.hanning(window_duration_samples)

output = np.zeros((filters.shape[0], windowed_audio.shape[1]), dtype=np.float32)
output_windowed = np.zeros((filters.shape[0], windowed_audio.shape[1]), dtype=np.float32)
for i in tqdm(range(windowed_audio.shape[1])):
   # calculate with no windowing
   filtered = erb_filterbank(windowed_audio[:, i], filters)
   output[:, i] = np.sum(filtered ** 2, axis=1)
   # calculate with windowing
   filtered = erb_filterbank(windowed_audio[:, i] * window, filters)
   output_windowed[:, i] = np.sum(filtered ** 2, axis=1)

# display log-power spectrograms, flip rows of outputs so low frequencies are at the bottom
fig, axes = plt.subplots(2,1, figsize=(8,8))
axes[0].set_title('No Window Function')
librosa.display.specshow(
   librosa.power_to_db(output[::-1], ref=np.max),
   ax=axes[0]
)
axes[1].set_title('Hanning Window')
librosa.display.specshow(
   librosa.power_to_db(output_windowed[::-1], ref=np.max),
   ax=axes[1]
)
plt.show()