Add backend module and put all the backend logics there

test/common_utils.py

@@ -10,7 +10,7 @@
 import torchaudio
 
 _TEST_DIR_PATH = os.path.dirname(os.path.realpath(__file__))
-BACKENDS = torchaudio._backend.list_audio_backends()
+BACKENDS = torchaudio.list_audio_backends()
 
 
 def get_asset_path(*paths):

torchaudio/__init__.py

@@ -11,19 +11,19 @@
     sox_effects,
     transforms
 )
-from torchaudio._backend import (
+from torchaudio.backend import (
+    list_audio_backends,
     get_audio_backend,
     set_audio_backend,
-)
-from torchaudio._sox_backend import (
     save_encinfo,
     sox_signalinfo_t,
     sox_encodinginfo_t,
     get_sox_option_t,
     get_sox_encoding_t,
     get_sox_bool,
+    SignalInfo,
+    EncodingInfo,
 )
-from torchaudio._soundfile_backend import SignalInfo, EncodingInfo
 from torchaudio._internal import (
     module_utils as _mod_utils,
     misc_ops as _misc_ops,

torchaudio/backend/__init__.py

@@ -0,0 +1,32 @@
+from .utils import (
+    list_audio_backends,
+    get_audio_backend,
+    set_audio_backend,
+)
+from .sox_backend import (
+    save_encinfo,
+    sox_signalinfo_t,
+    sox_encodinginfo_t,
+    get_sox_option_t,
+    get_sox_encoding_t,
+    get_sox_bool,
+)
+from .common import (
+    SignalInfo,
+    EncodingInfo,
+)
+
+
+def _init_backend():
+    backends = list_audio_backends()
+    if 'sox' in backends:
+        set_audio_backend('sox')
+    elif 'soundfile' in backends:
+        set_audio_backend('soundfile')
+    else:
+        import warnings
+        warnings.warn('No audio backend is available.')
+
+
+_init_backend()
+del _init_backend

torchaudio/backend/common.py

@@ -0,0 +1,31 @@
+from typing import Any, Optional
+
+
+class SignalInfo:
+    def __init__(self,
+                 channels: Optional[int] = None,
+                 rate: Optional[float] = None,
+                 precision: Optional[int] = None,
+                 length: Optional[int] = None) -> None:
+        self.channels = channels
+        self.rate = rate
+        self.precision = precision
+        self.length = length
+
+
+class EncodingInfo:
+    def __init__(self,
+                 encoding: Any = None,
+                 bits_per_sample: Optional[int] = None,
+                 compression: Optional[float] = None,
+                 reverse_bytes: Any = None,
+                 reverse_nibbles: Any = None,
+                 reverse_bits: Any = None,
+                 opposite_endian: Optional[bool] = None) -> None:
+        self.encoding = encoding
+        self.bits_per_sample = bits_per_sample
+        self.compression = compression
+        self.reverse_bytes = reverse_bytes
+        self.reverse_nibbles = reverse_nibbles
+        self.reverse_bits = reverse_bits
+        self.opposite_endian = opposite_endian

torchaudio/_soundfile_backend.py → torchaudio/backend/soundfile_backend.py

@@ -1,5 +1,5 @@
 import os
-from typing import Any, Optional, Tuple
+from typing import Optional, Tuple
 
 import torch
 from torch import Tensor
@@ -8,6 +8,7 @@
     module_utils as _mod_utils,
     misc_ops as _misc_ops,
 )
+from .common import SignalInfo, EncodingInfo
 
 if _mod_utils.is_module_available('soundfile'):
     import soundfile
@@ -22,36 +23,6 @@
 }
 
 
-class SignalInfo:
-    def __init__(self,
-                 channels: Optional[int] = None,
-                 rate: Optional[float] = None,
-                 precision: Optional[int] = None,
-                 length: Optional[int] = None) -> None:
-        self.channels = channels
-        self.rate = rate
-        self.precision = precision
-        self.length = length
-
-
-class EncodingInfo:
-    def __init__(self,
-                 encoding: Any = None,
-                 bits_per_sample: Optional[int] = None,
-                 compression: Optional[float] = None,
-                 reverse_bytes: Any = None,
-                 reverse_nibbles: Any = None,
-                 reverse_bits: Any = None,
-                 opposite_endian: Optional[bool] = None) -> None:
-        self.encoding = encoding
-        self.bits_per_sample = bits_per_sample
-        self.compression = compression
-        self.reverse_bytes = reverse_bytes
-        self.reverse_nibbles = reverse_nibbles
-        self.reverse_bits = reverse_bits
-        self.opposite_endian = opposite_endian
-
-
 @_mod_utils.requires_module('soundfile')
 def load(filepath: str,
          out: Optional[Tensor] = None,

torchaudio/_sox_backend.py → torchaudio/backend/sox_backend.py

@@ -8,10 +8,10 @@
     module_utils as _mod_utils,
     misc_ops as _misc_ops,
 )
-from torchaudio._soundfile_backend import SignalInfo, EncodingInfo
+from .common import SignalInfo, EncodingInfo
 
 if _mod_utils.is_module_available('torchaudio._torchaudio'):
-    from . import _torchaudio
+    from torchaudio import _torchaudio
 
 
 @_mod_utils.requires_module('torchaudio._torchaudio')

torchaudio/_backend.py → torchaudio/backend/utils.py

@@ -1,9 +1,15 @@
-import warnings
+"""Defines utilities for switching audio backends"""
 from typing import Optional, List
 
 import torchaudio
 from torchaudio._internal.module_utils import is_module_available
-from . import _soundfile_backend, _sox_backend
+from . import soundfile_backend, sox_backend
+
+__all__ = [
+    'list_audio_backends',
+    'get_audio_backend',
+    'set_audio_backend',
+]
 
 
 def list_audio_backends() -> List[str]:
@@ -29,9 +35,9 @@ def set_audio_backend(backend: str) -> None:
             f'available backends: {list_audio_backends()}.')
 
     if backend == 'sox':
-        module = _sox_backend
+        module = sox_backend
     elif backend == 'soundfile':
-        module = _soundfile_backend
+        module = soundfile_backend
     else:
         raise NotImplementedError(f'Unexpected backend "{backend}"')
 
@@ -41,21 +47,8 @@ def set_audio_backend(backend: str) -> None:
 
 def get_audio_backend() -> Optional[str]:
     """Get the name of the current backend"""
-    if torchaudio.load == _sox_backend.load:
+    if torchaudio.load == sox_backend.load:
         return 'sox'
-    if torchaudio.load == _soundfile_backend.load:
+    if torchaudio.load == soundfile_backend.load:
         return 'soundfile'
     return None
-
-
-def _init_backend():
-    backends = list_audio_backends()
-    if 'sox' in backends:
-        set_audio_backend('sox')
-    elif 'soundfile' in backends:
-        set_audio_backend('soundfile')
-    else:
-        warnings.warn('No audio backend is available.')
-
-
-_init_backend()