Small changes for flexibility and performance

auraloss/freq.py

@@ -2,7 +2,7 @@
 import numpy as np
 from typing import List, Any
 
-from .utils import apply_reduction
+from .utils import apply_reduction, get_window
 from .perceptual import SumAndDifference, FIRFilter
 
 
@@ -25,16 +25,29 @@ class STFTMagnitudeLoss(torch.nn.Module):
     See [Arik et al., 2018](https://arxiv.org/abs/1808.06719)
     and [Engel et al., 2020](https://arxiv.org/abs/2001.04643v1)
 
+    Log-magnitudes are calculated with `log(log_fac*x + log_eps)`, where `log_fac` controls the
+    compression strength (larger value results in more compression), and `log_eps` can be used
+    to control the range of the compressed output values (e.g., `log_eps>=1` ensures positive
+    output values). The default values `log_fac=1` and `log_eps=0` correspond to plain log-compression.
+
     Args:
         log (bool, optional): Log-scale the STFT magnitudes,
             or use linear scale. Default: True
+        log_eps (float, optional): Constant value added to the magnitudes before evaluating the logarithm.
+            Default: 0.0
+        log_fac (float, optional): Constant multiplication factor for the magnitudes before evaluating the logarithm.
+            Default: 1.0
         distance (str, optional): Distance function ["L1", "L2"]. Default: "L1"
         reduction (str, optional): Reduction of the loss elements. Default: "mean"
     """
 
-    def __init__(self, log=True, distance="L1", reduction="mean"):
+    def __init__(self, log=True, log_eps=0.0, log_fac=1.0, distance="L1", reduction="mean"):
         super(STFTMagnitudeLoss, self).__init__()
+
         self.log = log
+        self.log_eps = log_eps
+        self.log_fac = log_fac
+
         if distance == "L1":
             self.distance = torch.nn.L1Loss(reduction=reduction)
         elif distance == "L2":
@@ -44,8 +57,8 @@ def __init__(self, log=True, distance="L1", reduction="mean"):
 
     def forward(self, x_mag, y_mag):
         if self.log:
-            x_mag = torch.log(x_mag)
-            y_mag = torch.log(y_mag)
+            x_mag = torch.log(self.log_fac * x_mag + self.log_eps)
+            y_mag = torch.log(self.log_fac * y_mag + self.log_eps)
         return self.distance(x_mag, y_mag)
 
 
@@ -58,8 +71,9 @@ class STFTLoss(torch.nn.Module):
         fft_size (int, optional): FFT size in samples. Default: 1024
         hop_size (int, optional): Hop size of the FFT in samples. Default: 256
         win_length (int, optional): Length of the FFT analysis window. Default: 1024
-        window (str, optional): Window to apply before FFT, options include:
-           ['hann_window', 'bartlett_window', 'blackman_window', 'hamming_window', 'kaiser_window']
+        window (str, optional): Window to apply before FFT, can either be one of the window function provided in PyTorch
+            ['hann_window', 'bartlett_window', 'blackman_window', 'hamming_window', 'kaiser_window']
+            or any of the windows provided by [SciPy](https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.windows.get_window.html).
             Default: 'hann_window'
         w_sc (float, optional): Weight of the spectral convergence loss term. Default: 1.0
         w_log_mag (float, optional): Weight of the log magnitude loss term. Default: 1.0
@@ -112,12 +126,13 @@ def __init__(
         reduction: str = "mean",
         mag_distance: str = "L1",
         device: Any = None,
+        **kwargs
     ):
         super().__init__()
         self.fft_size = fft_size
         self.hop_size = hop_size
         self.win_length = win_length
-        self.window = getattr(torch, window)(win_length)
+        self.window = get_window(window, win_length)
         self.w_sc = w_sc
         self.w_log_mag = w_log_mag
         self.w_lin_mag = w_lin_mag
@@ -133,16 +148,20 @@ def __init__(
         self.mag_distance = mag_distance
         self.device = device
 
+        self.phs_used = bool(self.w_phs)
+
         self.spectralconv = SpectralConvergenceLoss()
         self.logstft = STFTMagnitudeLoss(
             log=True,
             reduction=reduction,
             distance=mag_distance,
+            **kwargs
         )
         self.linstft = STFTMagnitudeLoss(
             log=False,
             reduction=reduction,
             distance=mag_distance,
+            **kwargs
         )
 
         # setup mel filterbank
@@ -203,7 +222,13 @@ def stft(self, x):
         x_mag = torch.sqrt(
             torch.clamp((x_stft.real**2) + (x_stft.imag**2), min=self.eps)
         )
-        x_phs = torch.angle(x_stft)
+
+        # torch.angle is expensive, so it is only evaluated if the values are used in the loss
+        if self.phs_used:
+            x_phs = torch.angle(x_stft)
+        else:
+            x_phs = None
+
         return x_mag, x_phs
 
     def forward(self, input: torch.Tensor, target: torch.Tensor):
@@ -224,6 +249,7 @@ def forward(self, input: torch.Tensor, target: torch.Tensor):
 
         # compute the magnitude and phase spectra of input and target
         self.window = self.window.to(input.device)
+
         x_mag, x_phs = self.stft(input.view(-1, input.size(-1)))
         y_mag, y_phs = self.stft(target.view(-1, target.size(-1)))
 
@@ -242,7 +268,7 @@ def forward(self, input: torch.Tensor, target: torch.Tensor):
         sc_mag_loss = self.spectralconv(x_mag, y_mag) if self.w_sc else 0.0
         log_mag_loss = self.logstft(x_mag, y_mag) if self.w_log_mag else 0.0
         lin_mag_loss = self.linstft(x_mag, y_mag) if self.w_lin_mag else 0.0
-        phs_loss = torch.nn.functional.mse_loss(x_phs, y_phs) if self.w_phs else 0.0
+        phs_loss = torch.nn.functional.mse_loss(x_phs, y_phs) if self.phs_used else 0.0
 
         # combine loss terms
         loss = (

auraloss/utils.py

@@ -1,4 +1,5 @@
 import torch
+import scipy.signal
 
 
 def apply_reduction(losses, reduction="none"):
@@ -8,3 +9,23 @@ def apply_reduction(losses, reduction="none"):
     elif reduction == "sum":
         losses = losses.sum()
     return losses
+
+def get_window(win_type: str, win_length: int):
+    """Return a window function.
+
+    Args:
+        win_type (str): Window type. Can either be one of the window function provided in PyTorch
+            ['hann_window', 'bartlett_window', 'blackman_window', 'hamming_window', 'kaiser_window']
+            or any of the windows provided by [SciPy](https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.windows.get_window.html).
+        win_length (int): Window length
+
+    Returns:
+        win: The window as a 1D torch tensor
+    """
+
+    try:
+        win = getattr(torch, win_type)(win_length)
+    except:
+        win = torch.from_numpy(scipy.signal.windows.get_window(win_type, win_length))
+
+    return win