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- import torch
- import numpy as np
- from scipy.signal import get_window
- import librosa.util as librosa_util
-
-
- def window_sumsquare(window, n_frames, hop_length=200, win_length=800,
- n_fft=800, dtype=np.float32, norm=None):
- """
- # from librosa 0.6
- Compute the sum-square envelope of a window function at a given hop length.
-
- This is used to estimate modulation effects induced by windowing
- observations in short-time fourier transforms.
-
- Parameters
- ----------
- window : string, tuple, number, callable, or list-like
- Window specification, as in `get_window`
-
- n_frames : int > 0
- The number of analysis frames
-
- hop_length : int > 0
- The number of samples to advance between frames
-
- win_length : [optional]
- The length of the window function. By default, this matches `n_fft`.
-
- n_fft : int > 0
- The length of each analysis frame.
-
- dtype : np.dtype
- The data type of the output
-
- Returns
- -------
- wss : np.ndarray, shape=`(n_fft + hop_length * (n_frames - 1))`
- The sum-squared envelope of the window function
- """
- if win_length is None:
- win_length = n_fft
-
- n = n_fft + hop_length * (n_frames - 1)
- x = np.zeros(n, dtype=dtype)
-
- # Compute the squared window at the desired length
- win_sq = get_window(window, win_length, fftbins=True)
- win_sq = librosa_util.normalize(win_sq, norm=norm)**2
- win_sq = librosa_util.pad_center(win_sq, n_fft)
-
- # Fill the envelope
- for i in range(n_frames):
- sample = i * hop_length
- x[sample:min(n, sample + n_fft)
- ] += win_sq[:max(0, min(n_fft, n - sample))]
- return x
-
-
- def griffin_lim(magnitudes, stft_fn, n_iters=30):
- """
- PARAMS
- ------
- magnitudes: spectrogram magnitudes
- stft_fn: STFT class with transform (STFT) and inverse (ISTFT) methods
- """
-
- angles = np.angle(np.exp(2j * np.pi * np.random.rand(*magnitudes.size())))
- angles = angles.astype(np.float32)
- angles = torch.autograd.Variable(torch.from_numpy(angles))
- signal = stft_fn.inverse(magnitudes, angles).squeeze(1)
-
- for i in range(n_iters):
- _, angles = stft_fn.transform(signal)
- signal = stft_fn.inverse(magnitudes, angles).squeeze(1)
- return signal
-
-
- def dynamic_range_compression(x, C=1, clip_val=1e-5):
- """
- PARAMS
- ------
- C: compression factor
- """
- return torch.log(torch.clamp(x, min=clip_val) * C)
-
-
- def dynamic_range_decompression(x, C=1):
- """
- PARAMS
- ------
- C: compression factor used to compress
- """
- return torch.exp(x) / C
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