def get_window(window_type: str,
window_length_in_samp: int,
device: Optional[torch.device] = None) -> torch.Tensor:
# Increase precision in order to achieve parity with scipy.signal.windows.get_window implementation
if window_type == "bartlett":
return torch.bartlett_window(window_length_in_samp,
periodic=False,
dtype=torch.float64,
device=device).to(torch.float32)
elif window_type == "blackman":
return torch.blackman_window(window_length_in_samp,
periodic=False,
dtype=torch.float64,
device=device).to(torch.float32)
elif window_type == "hamming":
return torch.hamming_window(window_length_in_samp,
periodic=False,
dtype=torch.float64,
device=device).to(torch.float32)
elif window_type == "hann":
return torch.hann_window(window_length_in_samp,
periodic=False,
dtype=torch.float64,
device=device).to(torch.float32)
else:
raise ValueError(f"Unknown window type: {window_type}")
def spectral_ops(self):
a = torch.randn(10)
b = torch.randn(10, 8, 4, 2)
return (
torch.stft(a, 8),
torch.istft(b, 8),
torch.bartlett_window(2, dtype=torch.float),
torch.blackman_window(2, dtype=torch.float),
torch.hamming_window(4, dtype=torch.float),
torch.hann_window(4, dtype=torch.float),
torch.kaiser_window(4, dtype=torch.float),
)
def __init__(self,
n_fft=4096,
n_hop=1024,
center=False,
kind_window='hann'):
super(STFT, self).__init__()
# choose stft window
if kind_window == 'bartlett':
window = torch.bartlett_window(n_fft)
elif kind_window == 'gaussian':
window = gaussian_window(n_fft, 1 / sqrt(pi))
elif kind_window == 'hamming':
window = torch.hamming_window(n_fft)
elif kind_window == 'hann':
window = torch.hann_window(n_fft)
else:
raise NotImplementedError
self.window = nn.Parameter(window, requires_grad=False)
self.n_fft = n_fft
self.n_hop = n_hop
self.center = center
def _create_fb_matrix(self, n_fft):
""" Create a frequency bin conversion matrix.
Args:
n_fft (int): number of filter banks from spectrogram
"""
m_min = 0. if self.f_min == 0 else 2595 * np.log10(1. +
(self.f_min / 700))
m_max = 2595 * np.log10(1. + (self.f_max / 700))
m_pts = torch.linspace(m_min, m_max, self.n_mels + 2)
f_pts = (700 * (10**(m_pts / 2595) - 1))
bins = torch.floor(((n_fft - 1) * 2) * f_pts / self.sr).long()
fb = torch.zeros(n_fft, self.n_mels, dtype=torch.float)
for m in range(1, self.n_mels + 1):
f_m_minus = bins[m - 1].item()
f_m_plus = bins[m + 1].item()
fb[f_m_minus:f_m_plus,
m - 1] = torch.bartlett_window(f_m_plus - f_m_minus)
return fb
def _apply_probability_distribution(waveform, density_function="TPDF"):
# type: (Tensor, str) -> Tensor
r"""Apply a probability distribution function on a waveform.
Triangular probability density function (TPDF) dither noise has a
triangular distribution; values in the center of the range have a higher
probability of occurring.
Rectangular probability density function (RPDF) dither noise has a
uniform distribution; any value in the specified range has the same
probability of occurring.
Gaussian probability density function (GPDF) has a normal distribution.
The relationship of probabilities of results follows a bell-shaped,
or Gaussian curve, typical of dither generated by analog sources.
Args:
waveform (torch.Tensor): Tensor of audio of dimension (channel, time)
probability_density_function (string): The density function of a
continuous random variable (Default: `TPDF`)
Options: Triangular Probability Density Function - `TPDF`
Rectangular Probability Density Function - `RPDF`
Gaussian Probability Density Function - `GPDF`
Returns:
torch.Tensor: waveform dithered with TPDF
"""
shape = waveform.size()
waveform = waveform.reshape(-1, shape[-1])
channel_size = waveform.size()[0] - 1
time_size = waveform.size()[-1] - 1
random_channel = int(torch.randint(channel_size, [1, ]).item()) if channel_size > 0 else 0
random_time = int(torch.randint(time_size, [1, ]).item()) if time_size > 0 else 0
number_of_bits = 16
up_scaling = 2 ** (number_of_bits - 1) - 2
signal_scaled = waveform * up_scaling
down_scaling = 2 ** (number_of_bits - 1)
signal_scaled_dis = waveform
if (density_function == "RPDF"):
RPDF = waveform[random_channel][random_time] - 0.5
signal_scaled_dis = signal_scaled + RPDF
elif (density_function == "GPDF"):
# TODO Replace by distribution code once
# https://github.com/pytorch/pytorch/issues/29843 is resolved
# gaussian = torch.distributions.normal.Normal(torch.mean(waveform, -1), 1).sample()
num_rand_variables = 6
gaussian = waveform[random_channel][random_time]
for ws in num_rand_variables * [time_size]:
rand_chan = int(torch.randint(channel_size, [1, ]).item())
gaussian += waveform[rand_chan][int(torch.randint(ws, [1, ]).item())]
signal_scaled_dis = signal_scaled + gaussian
else:
TPDF = torch.bartlett_window(time_size + 1)
TPDF = TPDF.repeat((channel_size + 1), 1)
signal_scaled_dis = signal_scaled + TPDF
quantised_signal_scaled = torch.round(signal_scaled_dis)
quantised_signal = quantised_signal_scaled / down_scaling
return quantised_signal.reshape(shape[:-1] + quantised_signal.shape[-1:])