Update SpectralCentroid to accept window_fn and wkwargs (#1216)

Author: NicolasHug

torchaudio/transforms.py

@@ -1087,8 +1087,9 @@ class SpectralCentroid(torch.nn.Module):
         win_length (int or None, optional): Window size. (Default: ``n_fft``)
         hop_length (int or None, optional): Length of hop between STFT windows. (Default: ``win_length // 2``)
         pad (int, optional): Two sided padding of signal. (Default: ``0``)
-        window(Tensor, optional): A window tensor that is applied/multiplied to each frame.
-            (Default: ``torch.hann_window(win_length)``)
+        window_fn (Callable[..., Tensor], optional): A function to create a window tensor
+            that is applied/multiplied to each frame/window. (Default: ``torch.hann_window``)
+        wkwargs (dict or None, optional): Arguments for window function. (Default: ``None``)
 
     Example
         >>> waveform, sample_rate = torchaudio.load('test.wav', normalization=True)
@@ -1102,14 +1103,14 @@ def __init__(self,
                  win_length: Optional[int] = None,
                  hop_length: Optional[int] = None,
                  pad: int = 0,
-                 window: Optional[Tensor] = None) -> None:
+                 window_fn: Callable[..., Tensor] = torch.hann_window,
+                 wkwargs: Optional[dict] = None) -> None:
         super(SpectralCentroid, self).__init__()
         self.sample_rate = sample_rate
         self.n_fft = n_fft
         self.win_length = win_length if win_length is not None else n_fft
         self.hop_length = hop_length if hop_length is not None else self.win_length // 2
-        if window is None:
-            window = torch.hann_window(self.win_length)
+        window = window_fn(self.win_length) if wkwargs is None else window_fn(self.win_length, **wkwargs)
         self.register_buffer('window', window)
         self.pad = pad