Apply codec-based data augmentation

test/torchaudio_unittest/functional/functional_cpu_test.py

@@ -8,6 +8,12 @@
 import itertools
 
 from torchaudio_unittest import common_utils
+from torchaudio_unittest.common_utils import (
+    TorchaudioTestCase,
+    skipIfNoExtension,
+)
+from torchaudio_unittest.backend.sox_io.common import name_func
+
 from .functional_impl import Lfilter, Spectrogram
 
 
@@ -53,6 +59,7 @@ def test_warning(self):
 
 class TestComputeDeltas(common_utils.TorchaudioTestCase):
     """Test suite for correctness of compute_deltas"""
+
     def test_one_channel(self):
         specgram = torch.tensor([[[1.0, 2.0, 3.0, 4.0]]])
         expected = torch.tensor([[[0.5, 1.0, 1.0, 0.5]]])
@@ -211,3 +218,48 @@ def test_mask_along_axis_iid(self, mask_param, mask_value, axis):
 
         assert mask_specgrams.size() == specgrams.size()
         assert (num_masked_columns < mask_param).sum() == num_masked_columns.numel()
+
+
+@skipIfNoExtension
+class TestApplyCodec(TorchaudioTestCase):
+    backend = "sox_io"
+
+    def _smoke_test(self, format, compression, check_num_frames):
+        """
+        The purpose of this test suite is to verify that apply_codec functionalities do not exhibit
+        abnormal behaviors.
+        """
+        torch.random.manual_seed(42)
+        sample_rate = 8000
+        num_frames = 3 * sample_rate
+        num_channels = 2
+        waveform = torch.rand(num_channels, num_frames)
+
+        augmented = F.apply_codec(waveform,
+                                  sample_rate,
+                                  format,
+                                  True,
+                                  compression
+                                  )
+        assert augmented.dtype == waveform.dtype
+        assert augmented.shape[0] == num_channels
+        if check_num_frames:
+            assert augmented.shape[1] == num_frames
+
+    def test_wave(self):
+        self._smoke_test("wav", compression=None, check_num_frames=True)
+
+    @parameterized.expand([(96,), (128,), (160,), (192,), (224,), (256,), (320,)],
+                          name_func=name_func)
+    def test_mp3(self, compression):
+        self._smoke_test("mp3", compression, check_num_frames=False)
+
+    @parameterized.expand([(0,), (1,), (2,), (3,), (4,), (5,), (6,), (7,), (8,)],
+                          name_func=name_func)
+    def test_flac(self, compression):
+        self._smoke_test("flac", compression, check_num_frames=False)
+
+    @parameterized.expand([(-1,), (0,), (1,), (2,), (3,), (3.6,), (5,), (10,)],
+                          name_func=name_func)
+    def test_vorbis(self, compression):
+        self._smoke_test("vorbis", compression, check_num_frames=False)

torchaudio/functional/__init__.py

@@ -18,6 +18,7 @@
     sliding_window_cmn,
     spectrogram,
     spectral_centroid,
+    apply_codec,
 )
 from .filtering import (
     allpass_biquad,
@@ -84,4 +85,5 @@
     'riaa_biquad',
     'treble_biquad',
     'vad',
+    'apply_codec'
 ]

torchaudio/functional/functional.py

@@ -1,11 +1,16 @@
 # -*- coding: utf-8 -*-
 
+import io
 import math
-from typing import Optional, Tuple
 import warnings
+from typing import Optional, Tuple
 
 import torch
 from torch import Tensor
+from torchaudio._internal import (
+    module_utils as _mod_utils,
+)
+import torchaudio
 
 __all__ = [
     "spectrogram",
@@ -29,6 +34,7 @@
     'mask_along_axis_iid',
     'sliding_window_cmn',
     "spectral_centroid",
+    "apply_codec",
 ]
 
 
@@ -994,6 +1000,52 @@ def spectral_centroid(
     return (freqs * specgram).sum(dim=freq_dim) / specgram.sum(dim=freq_dim)
 
 
+@_mod_utils.requires_module('torchaudio._torchaudio')
+def apply_codec(
+    waveform: Tensor,
+    sample_rate: int,
+    format: str,
+    channels_first: bool = True,
+    compression: Optional[float] = None,
+    encoding: Optional[str] = None,
+    bits_per_sample: Optional[int] = None,
+) -> Tensor:
+    r"""
+    Applies codecs as a form of augmentation
+    Args:
+        waveform (Tensor): Audio data. Must be 2 dimensional. See also ```channels_first```
+        sample_rate (int): Sample rate of the audio waveform
+        format (str): file format
+        channels_first (bool):
+            When True, both the input and output Tensor have dimension ``[channel, time]``.
+            Otherwise, they have dimension ``[time, channel]``.
+        compression (float): Used for formats other than WAV.
+            For mor details see :py:func:`torchaudio.backend.sox_io_backend.save`
+        encoding (str, optional): Changes the encoding for the supported formats.
+            For more details see :py:func:`torchaudio.backend.sox_io_backend.save`
+        bits_per_sample (int, optional): Changes the bit depth for the supported formats.
+            For more details see :py:func:`torchaudio.backend.sox_io_backend.save`
+
+    Returns:
+        torch.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, _ = torchaudio.sox_effects.sox_effects.apply_effects_file(
+        bytes, effects=[["rate", f"{sample_rate}"]], channels_first=channels_first, format=format)
+    return augmented
+
+
 def compute_kaldi_pitch(
         waveform: torch.Tensor,
         sample_rate: float,