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audio.py
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audio.py
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import librosa
import librosa.filters
import numpy as np
import tensorflow as tf
from scipy import signal
from scipy.io import wavfile
from hyperparameters import hyperparameters as hp
def load_wav(path, sr):
return librosa.core.load(path, sr=sr)[0]
def save_wav(wav, path, sr):
wav *= 32767 / max(0.01, np.max(np.abs(wav)))
wavfile.write(path, sr, wav.astype(np.int16))
def save_wavenet_wav(wav, path, sr):
librosa.output.write_wav(path, wav, sr=sr)
def preemphasis(wav, k, preemphasize=True):
if preemphasize:
return signal.lfilter([1, -k], [1], wav)
return wav
def inv_preemphasis(wav, k, inv_preemphasize=True):
if inv_preemphasize:
return signal.lfilter([1], [1, -k], wav)
return wav
def get_hop_size():
hop_size = hp.hop_size #number of samples between each successive FFT window
if hop_size is None:
assert hp.frame_shift_ms is not None
hop_size = int(hp.frame_shift_ms / 1000 * hp.sample_rate)
return hop_size
def linearspectrogram(wav):
D = _stft(preemphasis(wav, hp.preemphasis, hp.preemphasize))
S = _amp_to_db(np.abs(D)) - hp.ref_level_db
if hp.signal_normalization:
return _normalize(S)
return S
def melspectrogram(wav):
D = _stft(preemphasis(wav, hp.preemphasis, hp.preemphasize))
S = _amp_to_db(_linear_to_mel(np.abs(D))) - hp.ref_level_db
if hp.signal_normalization:
return _normalize(S)
return S
def inv_linear_spectrogram(linear_spectrogram):
"""Converts linear spectrogram to waveform using librosa"""
if hp.signal_normalization:
D = _denormalize(linear_spectrogram)
else:
D = linear_spectrogram
S = _db_to_amp(D + hp.ref_level_db) #Convert back to linear
return inv_preemphasis(_griffin_lim(S ** hp.power), hp.preemphasis, hp.preemphasize)
def inv_mel_spectrogram(mel_spectrogram):
"""Converts mel spectrogram to waveform using librosa"""
if hp.signal_normalization:
D = _denormalize(mel_spectrogram)
else:
D = mel_spectrogram
S = _mel_to_linear(_db_to_amp(D + hp.ref_level_db)) # Convert back to linear
return inv_preemphasis(_griffin_lim(S ** hp.power), hp.preemphasis, hp.preemphasize)
def _griffin_lim(S):
angles = np.exp(2j * np.pi * np.random.rand(*S.shape))
S_complex = np.abs(S).astype(np.complex)
y = _istft(S_complex * angles)
for i in range(hp.griffin_lim_iters):
angles = np.exp(1j * np.angle(_stft(y)))
y = _istft(S_complex * angles)
return y
def _stft(y):
return librosa.stft(y=y, n_fft=hp.n_fft, hop_length=get_hop_size(), win_length=hp.win_size)
def _istft(y):
return librosa.istft(y, hop_length=get_hop_size(), win_length=hp.win_size)
##########################################################
def num_frames(length, fsize, fshift):
"""Compute number of time frames of spectrogram"""
pad = (fsize - fshift)
if length % fshift == 0:
M = (length + pad * 2 - fsize) // fshift + 1
else:
M = (length + pad * 2 - fsize) // fshift + 2
return M
def pad_lr(x, fsize, fshift):
"""Compute left and right padding"""
M = num_frames(len(x), fsize, fshift)
pad = (fsize - fshift)
T = len(x) + 2 * pad
r = (M - 1) * fshift + fsize - T
return pad, pad + r
##########################################################
#Librosa correct padding
def librosa_pad_lr(x, fsize, fshift):
return 0, (x.shape[0] // fshift + 1) * fshift - x.shape[0]
# Conversions
_mel_basis = None
_inv_mel_basis = None
def _linear_to_mel(spectogram):
global _mel_basis
if _mel_basis is None:
_mel_basis = _build_mel_basis()
return np.dot(_mel_basis, spectogram)
def _mel_to_linear(mel_spectrogram):
global _inv_mel_basis
if _inv_mel_basis is None:
_inv_mel_basis = np.linalg.pinv(_build_mel_basis())
return np.maximum(1e-10, np.dot(_inv_mel_basis, mel_spectrogram))
def _build_mel_basis():
assert hp.fmax <= hp.sample_rate // 2
return librosa.filters.mel(hp.sample_rate, hp.n_fft, n_mels=hp.num_mels,
fmin=hp.fmin, fmax=hp.fmax)
def _amp_to_db(x):
min_level = np.exp(hp.min_level_db / 20 * np.log(10))
return 20 * np.log10(np.maximum(min_level, x))
def _db_to_amp(x):
return np.power(10.0, (x) * 0.05)
def _normalize(S):
if hp.allow_clipping_in_normalization:
if hp.symmetric_mels:
return np.clip((2 * hp.max_abs_value) * ((S - hp.min_level_db) / (-hp.min_level_db)) - hp.max_abs_value,
-hp.max_abs_value, hp.max_abs_value)
else:
return np.clip(hp.max_abs_value * ((S - hp.min_level_db) / (-hp.min_level_db)), 0, hp.max_abs_value)
assert S.max() <= 0 and S.min() - hp.min_level_db >= 0
if hp.symmetric_mels:
return (2 * hp.max_abs_value) * ((S - hp.min_level_db) / (-hp.min_level_db)) - hp.max_abs_value
else:
return hp.max_abs_value * ((S - hp.min_level_db) / (-hp.min_level_db))
def _denormalize(D):
if hp.allow_clipping_in_normalization:
if hp.symmetric_mels:
return (((np.clip(D, -hp.max_abs_value,
hp.max_abs_value) + hp.max_abs_value) * -hp.min_level_db / (2 * hp.max_abs_value))
+ hp.min_level_db)
else:
return ((np.clip(D, 0, hp.max_abs_value) * -hp.min_level_db / hp.max_abs_value) + hp.min_level_db)
if hp.symmetric_mels:
return (((D + hp.max_abs_value) * -hp.min_level_db / (2 * hp.max_abs_value)) + hp.min_level_db)
else:
return ((D * -hp.min_level_db / hp.max_abs_value) + hp.min_level_db)