startup function `wavfile_read_mono`: support mono

profile_default/startup/init.py

@@ -51,6 +51,8 @@ def wavfile_read_mono(
 ) -> typing.Tuple[int, numpy.ndarray]:
     # https://docs.scipy.org/doc/scipy/reference/generated/scipy.io.wavfile.read.html
     rate, data = scipy.io.wavfile.read(path)
+    if len(data.shape) == 1:
+        return rate, data
     data_first_channel = data[:, 0]
     for channel_index in range(1, data.shape[1]):
         assert (data_first_channel == data[:, channel_index]).all()