Add pathlib.Path support to sox_io backend (#907)

torchaudio/backend/sox_io_backend.py

@@ -24,11 +24,15 @@ def info(filepath: str) -> AudioMetaData:
     """Get signal information of an audio file.
 
     Args:
-        filepath (str): Path to audio file
+        filepath (str or pathlib.Path):
+        Path to audio file. This function also handles ``pathlib.Path`` objects, but is annotated as
+        ``str`` for TorchScript compiler compatibility.
 
     Returns:
         AudioMetaData: meta data of the given audio.
     """
+    # Cast to str in case type is `pathlib.Path`
+    filepath = str(filepath)
     sinfo = torch.ops.torchaudio.sox_io_get_info(filepath)
     return AudioMetaData(sinfo.get_sample_rate(), sinfo.get_num_frames(), sinfo.get_num_channels())
 
@@ -80,8 +84,9 @@ def load(
     ``[-1.0, 1.0]``.
 
     Args:
-        filepath (str):
-            Path to audio file
+        filepath (str or pathlib.Path):
+            Path to audio file. This function also handles ``pathlib.Path`` objects, but is
+            annotated as ``str`` for TorchScript compiler compatibility.
         frame_offset (int):
             Number of frames to skip before start reading data.
         num_frames (int):
@@ -105,6 +110,8 @@ def load(
             integer type, else ``float32`` type. If ``channels_first=True``, it has
             ``[channel, time]`` else ``[time, channel]``.
     """
+    # Cast to str in case type is `pathlib.Path`
+    filepath = str(filepath)
     signal = torch.ops.torchaudio.sox_io_load_audio_file(
         filepath, frame_offset, num_frames, normalize, channels_first)
     return signal.get_tensor(), signal.get_sample_rate()
@@ -140,7 +147,9 @@ def save(
         and corresponding codec libraries such as ``libmad`` or ``libmp3lame`` etc.
 
     Args:
-        filepath (str): Path to save file.
+        filepath (str or pathlib.Path):
+            Path to save file. This function also handles ``pathlib.Path`` objects, but is annotated
+            as ``str`` for TorchScript compiler compatibility.
         tensor (torch.Tensor): Audio data to save. must be 2D tensor.
         sample_rate (int): sampling rate
         channels_first (bool):
@@ -158,6 +167,8 @@ def save(
 
             See the detail at http://sox.sourceforge.net/soxformat.html.
     """
+    # Cast to str in case type is `pathlib.Path`
+    filepath = str(filepath)
     if compression is None:
         ext = str(filepath).split('.')[-1].lower()
         if ext in ['wav', 'sph']: