# Source code for torchaudio.sox_effects.sox_effects

```
import os
from typing import List, Optional, Tuple
import torch
import torchaudio
from torchaudio._internal.module_utils import deprecated
from torchaudio.utils.sox_utils import list_effects
sox_ext = torchaudio._extension.lazy_import_sox_ext()
@deprecated("Please remove the call. This function is called automatically.")
def init_sox_effects():
"""Initialize resources required to use sox effects.
Note:
You do not need to call this function manually. It is called automatically.
Once initialized, you do not need to call this function again across the multiple uses of
sox effects though it is safe to do so as long as :func:`shutdown_sox_effects` is not called yet.
Once :func:`shutdown_sox_effects` is called, you can no longer use SoX effects and initializing
again will result in error.
"""
pass
@deprecated("Please remove the call. This function is called automatically.")
def shutdown_sox_effects():
"""Clean up resources required to use sox effects.
Note:
You do not need to call this function manually. It is called automatically.
It is safe to call this function multiple times.
Once :py:func:`shutdown_sox_effects` is called, you can no longer use SoX effects and
initializing again will result in error.
"""
pass
[docs]def effect_names() -> List[str]:
"""Gets list of valid sox effect names
Returns:
List[str]: list of available effect names.
Example
>>> torchaudio.sox_effects.effect_names()
['allpass', 'band', 'bandpass', ... ]
"""
return list(list_effects().keys())
[docs]def apply_effects_tensor(
tensor: torch.Tensor,
sample_rate: int,
effects: List[List[str]],
channels_first: bool = True,
) -> Tuple[torch.Tensor, int]:
"""Apply sox effects to given Tensor
.. devices:: CPU
.. properties:: TorchScript
Note:
This function only works on CPU Tensors.
This function works in the way very similar to ``sox`` command, however there are slight
differences. For example, ``sox`` command adds certain effects automatically (such as
``rate`` effect after ``speed`` and ``pitch`` and other effects), but this function does
only applies the given effects. (Therefore, to actually apply ``speed`` effect, you also
need to give ``rate`` effect with desired sampling rate.).
Args:
tensor (torch.Tensor): Input 2D CPU Tensor.
sample_rate (int): Sample rate
effects (List[List[str]]): List of effects.
channels_first (bool, optional): Indicates if the input Tensor's dimension is
`[channels, time]` or `[time, channels]`
Returns:
(Tensor, int): Resulting Tensor and sample rate.
The resulting Tensor has the same ``dtype`` as the input Tensor, and
the same channels order. The shape of the Tensor can be different based on the
effects applied. Sample rate can also be different based on the effects applied.
Example - Basic usage
>>>
>>> # Defines the effects to apply
>>> effects = [
... ['gain', '-n'], # normalises to 0dB
... ['pitch', '5'], # 5 cent pitch shift
... ['rate', '8000'], # resample to 8000 Hz
... ]
>>>
>>> # Generate pseudo wave:
>>> # normalized, channels first, 2ch, sampling rate 16000, 1 second
>>> sample_rate = 16000
>>> waveform = 2 * torch.rand([2, sample_rate * 1]) - 1
>>> waveform.shape
torch.Size([2, 16000])
>>> waveform
tensor([[ 0.3138, 0.7620, -0.9019, ..., -0.7495, -0.4935, 0.5442],
[-0.0832, 0.0061, 0.8233, ..., -0.5176, -0.9140, -0.2434]])
>>>
>>> # Apply effects
>>> waveform, sample_rate = apply_effects_tensor(
... wave_form, sample_rate, effects, channels_first=True)
>>>
>>> # Check the result
>>> # The new waveform is sampling rate 8000, 1 second.
>>> # normalization and channel order are preserved
>>> waveform.shape
torch.Size([2, 8000])
>>> waveform
tensor([[ 0.5054, -0.5518, -0.4800, ..., -0.0076, 0.0096, -0.0110],
[ 0.1331, 0.0436, -0.3783, ..., -0.0035, 0.0012, 0.0008]])
>>> sample_rate
8000
Example - Torchscript-able transform
>>>
>>> # Use `apply_effects_tensor` in `torch.nn.Module` and dump it to file,
>>> # then run sox effect via Torchscript runtime.
>>>
>>> class SoxEffectTransform(torch.nn.Module):
... effects: List[List[str]]
...
... def __init__(self, effects: List[List[str]]):
... super().__init__()
... self.effects = effects
...
... def forward(self, tensor: torch.Tensor, sample_rate: int):
... return sox_effects.apply_effects_tensor(
... tensor, sample_rate, self.effects)
...
...
>>> # Create transform object
>>> effects = [
... ["lowpass", "-1", "300"], # apply single-pole lowpass filter
... ["rate", "8000"], # change sample rate to 8000
... ]
>>> transform = SoxEffectTensorTransform(effects, input_sample_rate)
>>>
>>> # Dump it to file and load
>>> path = 'sox_effect.zip'
>>> torch.jit.script(trans).save(path)
>>> transform = torch.jit.load(path)
>>>
>>>> # Run transform
>>> waveform, input_sample_rate = torchaudio.load("input.wav")
>>> waveform, sample_rate = transform(waveform, input_sample_rate)
>>> assert sample_rate == 8000
"""
return sox_ext.apply_effects_tensor(tensor, sample_rate, effects, channels_first)
[docs]def apply_effects_file(
path: str,
effects: List[List[str]],
normalize: bool = True,
channels_first: bool = True,
format: Optional[str] = None,
) -> Tuple[torch.Tensor, int]:
"""Apply sox effects to the audio file and load the resulting data as Tensor
.. devices:: CPU
.. properties:: TorchScript
Note:
This function works in the way very similar to ``sox`` command, however there are slight
differences. For example, ``sox`` commnad adds certain effects automatically (such as
``rate`` effect after ``speed``, ``pitch`` etc), but this function only applies the given
effects. Therefore, to actually apply ``speed`` effect, you also need to give ``rate``
effect with desired sampling rate, because internally, ``speed`` effects only alter sampling
rate and leave samples untouched.
Args:
path (path-like object):
Source of audio data.
effects (List[List[str]]): List of effects.
normalize (bool, optional):
When ``True``, this function converts the native sample type to ``float32``.
Default: ``True``.
If input file is integer WAV, giving ``False`` will change the resulting Tensor type to
integer type.
This argument has no effect for formats other than integer WAV type.
channels_first (bool, optional): When True, the returned Tensor has dimension `[channel, time]`.
Otherwise, the returned Tensor's dimension is `[time, channel]`.
format (str or None, optional):
Override the format detection with the given format.
Providing the argument might help when libsox can not infer the format
from header or extension,
Returns:
(Tensor, int): Resulting Tensor and sample rate.
If ``normalize=True``, the resulting Tensor is always ``float32`` type.
If ``normalize=False`` and the input audio file is of integer WAV file, then the
resulting Tensor has corresponding integer type. (Note 24 bit integer type is not supported)
If ``channels_first=True``, the resulting Tensor has dimension `[channel, time]`,
otherwise `[time, channel]`.
Example - Basic usage
>>>
>>> # Defines the effects to apply
>>> effects = [
... ['gain', '-n'], # normalises to 0dB
... ['pitch', '5'], # 5 cent pitch shift
... ['rate', '8000'], # resample to 8000 Hz
... ]
>>>
>>> # Apply effects and load data with channels_first=True
>>> waveform, sample_rate = apply_effects_file("data.wav", effects, channels_first=True)
>>>
>>> # Check the result
>>> waveform.shape
torch.Size([2, 8000])
>>> waveform
tensor([[ 5.1151e-03, 1.8073e-02, 2.2188e-02, ..., 1.0431e-07,
-1.4761e-07, 1.8114e-07],
[-2.6924e-03, 2.1860e-03, 1.0650e-02, ..., 6.4122e-07,
-5.6159e-07, 4.8103e-07]])
>>> sample_rate
8000
Example - Apply random speed perturbation to dataset
>>>
>>> # Load data from file, apply random speed perturbation
>>> class RandomPerturbationFile(torch.utils.data.Dataset):
... \"\"\"Given flist, apply random speed perturbation
...
... Suppose all the input files are at least one second long.
... \"\"\"
... def __init__(self, flist: List[str], sample_rate: int):
... super().__init__()
... self.flist = flist
... self.sample_rate = sample_rate
...
... def __getitem__(self, index):
... speed = 0.5 + 1.5 * random.randn()
... effects = [
... ['gain', '-n', '-10'], # apply 10 db attenuation
... ['remix', '-'], # merge all the channels
... ['speed', f'{speed:.5f}'], # duration is now 0.5 ~ 2.0 seconds.
... ['rate', f'{self.sample_rate}'],
... ['pad', '0', '1.5'], # add 1.5 seconds silence at the end
... ['trim', '0', '2'], # get the first 2 seconds
... ]
... waveform, _ = torchaudio.sox_effects.apply_effects_file(
... self.flist[index], effects)
... return waveform
...
... def __len__(self):
... return len(self.flist)
...
>>> dataset = RandomPerturbationFile(file_list, sample_rate=8000)
>>> loader = torch.utils.data.DataLoader(dataset, batch_size=32)
>>> for batch in loader:
>>> pass
"""
if not torch.jit.is_scripting():
if hasattr(path, "read"):
raise RuntimeError(
"apply_effects_file function does not support file-like object. "
"Please use torchaudio.io.AudioEffector."
)
path = os.fspath(path)
return sox_ext.apply_effects_file(path, effects, normalize, channels_first, format)
```