startup: define function `wavfile_read_mono` wrapping `scipy.io.wavfile.read`

profile_default/startup/init.py

@@ -0,0 +1,10 @@
+import scipy.io.wavfile
+
+
+def wavfile_read_mono(path):
+    # https://docs.scipy.org/doc/scipy/reference/generated/scipy.io.wavfile.read.html
+    rate, data = scipy.io.wavfile.read(path)
+    data_first_channel = data[:, 0]
+    for channel_index in range(1, data.shape[1]):
+        assert (data_first_channel == data[:, channel_index]).all()
+    return rate, data_first_channel