Fade

class auglib.transform.Fade(*, in_dur=0.1, out_dur=0.1, in_shape='tukey', out_shape='tukey', in_db=-120, out_db=-120, unit='seconds', preserve_level=False, bypass_prob=None)

Fade-in and fade-out of signal.

A fade is a gradual increase (fade-in) or decrease (fade-out) in the level of an audio signal. If in_db is greater than -120 dB the fade-in will start from the corresponding level, otherwise from silence. If out_db is greater than -120 dB the fade-out will end at the corresponding level, otherwise from silence.

The shape of the fade-in and fade-out is selected via in_shape and out_shape. The following figure shows all available shapes by the example of a fade-in.

Parameters

• in_dur (typing.Union[int, float, auglib.core.observe.Base, auglib.core.time.Time]) – duration of fade-in

• out_dur (typing.Union[int, float, auglib.core.observe.Base, auglib.core.time.Time]) – duration of fade-out

• in_shape (str) – shape of fade-in

• out_shape (str) – shape of fade-out

• in_db (float) – level in dB the fade-in should start at, -120 dB or less is equivalent to an amplitude of 0

• out_db (float) – level in dB the fade-out should end at, -120 dB or less is equivalent to an amplitude of 0

• unit (str) – literal specifying the format of duration (see auglib.utils.to_samples()).

• preserve_level (typing.Union[bool, auglib.core.observe.Base]) – if True the root mean square value of the augmented signal will be the same as before augmentation

• bypass_prob (typing.Union[float, auglib.core.observe.Base, None]) – probability to bypass the transformation

Raises

• ValueError – if in_shape or out_shape contains a non-supported value

• ValueError – if in_db or out_db are greater or equal to 0

Examples

Fade in a speech signal by 0.2 s, and fade out by 0.7 s.

>>> import audb
>>> import audiofile
>>> import audplot
>>> import auglib
>>> transform = auglib.transform.Fade(in_dur=0.2, out_dur=0.7)
>>> files = audb.load_media("emodb", "wav/03a01Fa.wav", version="1.4.1")
>>> signal, sampling_rate = audiofile.read(files[0])
>>> augmented_signal = transform(signal, sampling_rate)
>>> audplot.waveform(augmented_signal)

Inspect fade window.

>>> import numpy as np
>>> signal = np.ones(signal.shape)
>>> augmented_signal = transform(signal, sampling_rate)
>>> audplot.waveform(augmented_signal)

__call__()

Fade.__call__(signal, sampling_rate=None)

Apply transform to signal.

Parameters

• signal (numpy.ndarray) – signal to be transformed

• sampling_rate (typing.Optional[int]) – sampling rate in Hz

Return type

numpy.ndarray

Returns

augmented signal

Raises

• ValueError – if the signal shape is not support by chosen transform parameters

• ValueError – if sampling_rate is None, but the transform requires a samling rate

• RuntimeError – if the given sampling rate is incompatible with the transform

arguments

Fade.arguments

Returns arguments that are serialized.

Returns

Dictionary of arguments and their values.

Raises

RuntimeError – if arguments are found that are not assigned to attributes of the same name

Examples

>>> import audobject.testing
>>> o = audobject.testing.TestObject('test', point=(1, 1))
>>> o.arguments
{'name': 'test', 'point': (1, 1)}

borrowed_arguments

Fade.borrowed_arguments

Returns borrowed arguments.

Returns

Dictionary with borrowed arguments.

from_dict()

static Fade.from_dict(d, root=None, **kwargs)

Return type

audobject.core.object.Object

from_yaml()

static Fade.from_yaml(path_or_stream, **kwargs)

Return type

audobject.core.object.Object

from_yaml_s()

static Fade.from_yaml_s(yaml_string, **kwargs)

Return type

audobject.core.object.Object

hidden_arguments

Fade.hidden_arguments

Returns hidden arguments.

Returns

List with names of hidden arguments.

id

Fade.id

Object identifier.

The ID of an object ID is created from its non-hidden arguments.

Returns

object identifier

Examples

>>> class Foo(Object):
...    def __init__(self, bar: str):
...        self.bar = bar
>>> foo1 = Foo('I am unique!')
>>> foo1.id
'893df240-babe-d796-cdf1-c436171b7a96'
>>> foo2 = Foo('I am different!')
>>> foo2.id
'9303f2a5-bfc9-e5ff-0ffa-a9846e2d2190'
>>> foo3 = Foo('I am unique!')
>>> foo1.id == foo3.id
True

is_loaded_from_dict

Fade.is_loaded_from_dict

Check if object was loaded from a dictionary.

Returns True if object was initialized from a dictionary, e.g. after loading it from a YAML file.

Returns

True if object was loaded from a dictionary,

otherwise False

resolvers

Fade.resolvers

Return resolvers.

Returns

Dictionary with resolvers.

short_id

Fade.short_id

Short object identifier.

The short ID consists of eight characters and is created from its non-hidden arguments.

Returns

short object identifier

Examples

>>> class Foo(Object):
...    def __init__(self, bar: str):
...        self.bar = bar
>>> foo1 = Foo('I am unique!')
>>> foo1.id
'893df240-babe-d796-cdf1-c436171b7a96'
>>> foo1.short_id
'171b7a96'
>>> foo2 = Foo('I am different!')
>>> foo2.short_id
'6e2d2190'
>>> foo3 = Foo('I am unique!')
>>> foo1.short_id == foo3.short_id
True

to_dict()

Fade.to_dict(*, include_version=True, flatten=False, root=None)

Converts object to a dictionary.

Includes items from audobject.Object.arguments. If an argument has a resolver, its value is encoded. Usually, the object can be re-instantiated using audobject.Object.from_dict(). However, if flatten=True, this is not possible.

Parameters

• include_version (bool) – add version to class name

• flatten (bool) – flatten the dictionary

• root (typing.Optional[str]) – if file is written to disk, set to target directory

Return type

typing.Dict[str, typing.Union[bool, datetime.datetime, dict, float, int, list, None, str]]

Returns

dictionary that represent the object

Examples

>>> import audobject.testing
>>> o = audobject.testing.TestObject('test', point=(1, 1))
>>> o.to_dict(include_version=False)
{'$audobject.core.testing.TestObject': {'name': 'test', 'point': [1, 1]}}
>>> o.to_dict(flatten=True)
{'name': 'test', 'point.0': 1, 'point.1': 1}

to_samples()

Fade.to_samples(value, sampling_rate=None, *, length=None, allow_negative=True)

Convert duration value to samples.

Return type

int

to_yaml()

Fade.to_yaml(path_or_stream, *, include_version=True)

Save object to YAML file.

Parameters

• path_or_stream (typing.Union[str, typing.IO]) – file path or stream

• include_version (bool) – add version to class name

to_yaml_s()

Fade.to_yaml_s(*, include_version=True)

Convert object to YAML string.

Parameters

include_version (bool) – add version to class name

Return type

str

Returns

YAML string

Examples

>>> import audobject.testing
>>> o = audobject.testing.TestObject('test', point=(1, 1))
>>> print(o.to_yaml_s(include_version=False))
$audobject.core.testing.TestObject:
  name: test
  point:
  - 1
  - 1