193 lines
7.3 KiB
Python
193 lines
7.3 KiB
Python
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"""
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BSD 3-Clause License
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Copyright (c) 2017, Prem Seetharaman
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All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice, this
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list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the names of its
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contributors may be used to endorse or promote products derived from this
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software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"""
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import torch
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import numpy as np
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import torch.nn.functional as F
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from torch.autograd import Variable
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from scipy.signal import get_window
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from librosa.util import pad_center, tiny
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import librosa.util as librosa_util
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def window_sumsquare(window, n_frames, hop_length=200, win_length=800,
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n_fft=800, dtype=np.float32, norm=None):
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"""
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# from librosa 0.6
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Compute the sum-square envelope of a window function at a given hop length.
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This is used to estimate modulation effects induced by windowing
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observations in short-time fourier transforms.
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Parameters
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----------
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window : string, tuple, number, callable, or list-like
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Window specification, as in `get_window`
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n_frames : int > 0
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The number of analysis frames
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hop_length : int > 0
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The number of samples to advance between frames
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win_length : [optional]
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The length of the window function. By default, this matches `n_fft`.
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n_fft : int > 0
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The length of each analysis frame.
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dtype : np.dtype
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The data type of the output
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Returns
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-------
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wss : np.ndarray, shape=`(n_fft + hop_length * (n_frames - 1))`
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The sum-squared envelope of the window function
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"""
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if win_length is None:
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win_length = n_fft
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n = n_fft + hop_length * (n_frames - 1)
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x = np.zeros(n, dtype=dtype)
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# Compute the squared window at the desired length
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win_sq = get_window(window, win_length, fftbins=True)
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win_sq = librosa_util.normalize(win_sq, norm=norm)**2
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win_sq = librosa_util.pad_center(win_sq, n_fft)
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# Fill the envelope
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for i in range(n_frames):
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sample = i * hop_length
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x[sample:min(n, sample + n_fft)] += win_sq[:max(0, min(n_fft, n - sample))]
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return x
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class STFT(torch.nn.Module):
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"""adapted from Prem Seetharaman's https://github.com/pseeth/pytorch-stft"""
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def __init__(self, filter_length=800, hop_length=200, win_length=800,
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window='hann'):
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super(STFT, self).__init__()
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self.filter_length = filter_length
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self.hop_length = hop_length
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self.win_length = win_length
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self.window = window
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self.forward_transform = None
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scale = self.filter_length / self.hop_length
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fourier_basis = np.fft.fft(np.eye(self.filter_length))
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cutoff = int((self.filter_length / 2 + 1))
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fourier_basis = np.vstack([np.real(fourier_basis[:cutoff, :]),
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np.imag(fourier_basis[:cutoff, :])])
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forward_basis = torch.FloatTensor(fourier_basis[:, None, :])
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inverse_basis = torch.FloatTensor(
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np.linalg.pinv(scale * fourier_basis).T[:, None, :])
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if window is not None:
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assert(filter_length >= win_length)
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# get window and zero center pad it to filter_length
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fft_window = get_window(window, win_length, fftbins=True)
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fft_window = pad_center(fft_window, filter_length)
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fft_window = torch.from_numpy(fft_window).float()
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# window the bases
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forward_basis *= fft_window
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inverse_basis *= fft_window
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self.register_buffer('forward_basis', forward_basis.float())
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self.register_buffer('inverse_basis', inverse_basis.float())
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def transform(self, input_data):
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num_batches = input_data.size(0)
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num_samples = input_data.size(1)
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self.num_samples = num_samples
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# similar to librosa, reflect-pad the input
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input_data = input_data.view(num_batches, 1, num_samples)
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input_data = F.pad(
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input_data.unsqueeze(1),
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(int(self.filter_length / 2), int(self.filter_length / 2), 0, 0),
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mode='reflect')
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input_data = input_data.squeeze(1)
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forward_transform = F.conv1d(
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input_data,
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Variable(self.forward_basis, requires_grad=False),
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stride=self.hop_length,
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padding=0)
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cutoff = int((self.filter_length / 2) + 1)
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real_part = forward_transform[:, :cutoff, :]
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imag_part = forward_transform[:, cutoff:, :]
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magnitude = torch.sqrt(real_part**2 + imag_part**2)
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phase = torch.autograd.Variable(
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torch.atan2(imag_part.data, real_part.data))
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return magnitude, phase
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def inverse(self, magnitude, phase):
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recombine_magnitude_phase = torch.cat(
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[magnitude*torch.cos(phase), magnitude*torch.sin(phase)], dim=1)
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inverse_transform = F.conv_transpose1d(
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recombine_magnitude_phase,
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Variable(self.inverse_basis, requires_grad=False),
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stride=self.hop_length,
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padding=0)
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if self.window is not None:
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window_sum = window_sumsquare(
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self.window, magnitude.size(-1), hop_length=self.hop_length,
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win_length=self.win_length, n_fft=self.filter_length,
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dtype=np.float32)
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# remove modulation effects
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approx_nonzero_indices = torch.from_numpy(
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np.where(window_sum > tiny(window_sum))[0])
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window_sum = torch.autograd.Variable(
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torch.from_numpy(window_sum), requires_grad=False)
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window_sum = window_sum.cuda() if magnitude.is_cuda else window_sum
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inverse_transform[:, :, approx_nonzero_indices] /= window_sum[approx_nonzero_indices]
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# scale by hop ratio
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inverse_transform *= float(self.filter_length) / self.hop_length
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inverse_transform = inverse_transform[:, :, int(self.filter_length/2):]
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inverse_transform = inverse_transform[:, :, :-int(self.filter_length/2):]
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return inverse_transform
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def forward(self, input_data):
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self.magnitude, self.phase = self.transform(input_data)
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reconstruction = self.inverse(self.magnitude, self.phase)
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return reconstruction
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