Update and deprecate apply_codec function (#3386)

Summary:
To prepare for the upcoming removal of file-like object support from sox_io backend,
this commit changes apply_codec function to use tempfile.

`apply_codec` function is now deprecated and users are encourated to use `torchaudio.io.AudioEffector`.
We will not remove the function itself, but will remove the entry from the doc.

Pull Request resolved: https://github.com/pytorch/audio/pull/3386

Reviewed By: hwangjeff

Differential Revision: D46330610

Pulled By: mthrok

fbshipit-source-id: 3071bdefa05b4cbb9f00629bef50f0981eae89b4

torchaudio/_internal/module_utils.py

@@ -40,7 +40,7 @@ def requires_module(*modules: str):
     return decorator
 
 
-def deprecated(direction: str, version: Optional[str] = None):
+def deprecated(direction: str, version: Optional[str] = None, remove: bool = False):
     """Decorator to add deprecation message
 
     Args:
@@ -51,11 +51,9 @@ def deprecated(direction: str, version: Optional[str] = None):
     def decorator(func):
         @wraps(func)
         def wrapped(*args, **kwargs):
-            message = (
-                f"{func.__module__}.{func.__name__} has been deprecated "
-                f'and will be removed from {"future" if version is None else version} release. '
-                f"{direction}"
-            )
+            message = f"{func.__module__}.{func.__name__} has been deprecated. {direction}"
+            if remove:
+                message += f' It will be removed from {"future" if version is None else version} release. '
             warnings.warn(message, stacklevel=2)
             return func(*args, **kwargs)
 

torchaudio/functional/functional.py

 # -*- coding: utf-8 -*-
 
-import io
 import math
+import tempfile
 import warnings
 from collections.abc import Sequence
 from typing import List, Optional, Tuple, Union
@@ -10,6 +10,7 @@ import torch
 import torchaudio
 from torch import Tensor
 from torchaudio._extension import fail_if_no_align
+from torchaudio._internal.module_utils import deprecated
 
 from .filtering import highpass_biquad, treble_biquad
 
@@ -1290,6 +1291,7 @@ def spectral_centroid(
 
 
 @torchaudio._extension.fail_if_no_sox
+@deprecated("Please migrate to torchaudio.io.AudioEffector.", remove=False)
 def apply_codec(
     waveform: Tensor,
     sample_rate: int,
@@ -1304,6 +1306,12 @@ def apply_codec(
 
     .. devices:: CPU
 
+    .. warnings::
+
+       This function has been deprecated.
+       Please migrate to :py:class:`torchaudio.io.AudioEffector`, which works on all platforms,
+       and supports streaming processing.
+
     Args:
         waveform (Tensor): Audio data. Must be 2 dimensional. See also ```channels_first```.
         sample_rate (int): Sample rate of the audio waveform.
@@ -1322,12 +1330,12 @@ def apply_codec(
         Tensor: Resulting Tensor.
         If ``channels_first=True``, it has `(channel, time)` else `(time, channel)`.
     """
-    bytes = io.BytesIO()
-    torchaudio.backend.sox_io_backend.save(
-        bytes, waveform, sample_rate, channels_first, compression, format, encoding, bits_per_sample
-    )
-    bytes.seek(0)
-    augmented, sr = torchaudio.backend.sox_io_backend.load(bytes, channels_first=channels_first, format=format)
+    with tempfile.TemporaryFile() as f:
+        torchaudio.backend.sox_io_backend.save(
+            f, waveform, sample_rate, channels_first, compression, format, encoding, bits_per_sample
+        )
+        f.seek(0)
+        augmented, sr = torchaudio.backend.sox_io_backend.load(f, channels_first=channels_first, format=format)
     if sr != sample_rate:
         augmented = resample(augmented, sr, sample_rate)
     return augmented