gensound.effect

The module of audio effects

class gensound.effect.Effect

Bases: object

Base class of sound effect

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A Sound instance that applied effect.

You can use shift operator as apply() like a streaming operator of C++.

>>> effect = LinearFadeIn()
>>> sound = Sound.from_sinwave(440)
>>> effect.apply(sound) == (effect << sound) == (sound >> effect)
True

then(effect)

Join effect

Effect:Effect that will apply after this effect. Return type:Effect Returns:Joined effect.

>>> in_ = LinearFadeIn()
>>> out = LinearFadeOut()
>>> sound = Sound.from_sinwave(440)

>>> out.apply(in_.apply(sound)) == in_.then(out).apply(sound)
True

You can use shift operator as then() like a streaming operator of C++.

>>> sound >> in_ >> out == in_.then(out).apply(sound)
True

class gensound.effect.JoinedEffect(*effects: gensound.effect.Effect) → None

Bases: gensound.effect.Effect

Joined multiple effects

Parameters:effects (Effect) – Effect instances to joint. Raises:ValueError – If effects not given.

>>> in_ = LinearFadeIn()
>>> out = LinearFadeOut()
>>> sound = Sound.from_sinwave(440)

>>> out.apply(in_.apply(sound)) == JoinedEffect(in_, out).apply(sound)
True

>>> out.apply(in_.apply(sound)) == in_.then(out).apply(sound)
True

>>> out << in_ << sound == JoinedEffect(in_, out).apply(sound)
True

apply(sound)

Apply all effects

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied all effects.

class gensound.effect.MaskEffect(duration: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.Effect

Masking effect

Parameters:duration (Optional[float]) – Duration in seconds of mask. Mathing to sound duration if None.

gen_mask(length)

Generate mask

Parameters:length (int) – Length of mask array. Return type:<built-in function array> Returns:Mask value.

class gensound.effect.MaskStartEffect(duration: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.MaskEffect

Effect that masking start of sound

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.MaskEndEffect(duration: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.MaskEffect

Effect that masking end of sound

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.LinearFadeIn(duration: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.MaskStartEffect

Linear fade-in effect

Parameters:duration (Optional[float]) – Duration in seconds of mask. Mathing to sound duration if None.

>>> s = Sound.from_array([1, 1, 1, 1, 1], 1)
>>> (LinearFadeIn().apply(s)
...  == Sound.from_array([0.0, 0.25, 0.5, 0.75, 1.0], 1))
True
>>> (LinearFadeIn(duration=3).apply(s)
...  == Sound.from_array([0.0, 0.5, 1.0, 1.0, 1.0], 1))
True

gen_mask(length)

Return type:<built-in function array>

class gensound.effect.LinearFadeOut(duration: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.MaskEndEffect

Linear fade-out effect

Parameters:duration (Optional[float]) – Duration in seconds of mask. Mathing to sound duration if None.

>>> s = Sound.from_array([1, 1, 1, 1, 1], 1)
>>> (LinearFadeOut().apply(s)
...  == Sound.from_array([1.0, 0.75, 0.5, 0.25, 0.0], 1))
True
>>> (LinearFadeOut(duration=3).apply(s)
...  == Sound.from_array([1.0, 1.0, 1.0, 0.5, 0.0], 1))
True

gen_mask(length)

Return type:<built-in function array>

class gensound.effect.LowPassFilter(freq: float) → None

Bases: gensound.effect.Effect

Low pass filter

Parameters:freq (float) – A threshold frequency.

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.HighPassFilter(freq: float) → None

Bases: gensound.effect.Effect

High pass filter

Parameters:freq (float) – A threshold frequency.

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.Resampling(samplerate: float, kind: str = 'cubic') → None

Bases: gensound.effect.Effect

Resampling effect

Parameters:

• samplerate (float) – New sampling rate.
• kind (str) – The way to interpolating data. Please see document of scipy.interpolate.interp1d.

Change sampling rate without changes sound duration.

If the sampling rate of passed sound is same as target sampling rate, will return the same instance without re-sampling process.

This example does resampling from 44100 Hz to 88200 Hz.

>>> original = Sound.from_sinwave(440, duration=1, samplerate=44100)
>>> original.samplerate
44100
>>> abs(original.duration - 1) < 0.01
True

>>> resampled = Resampling(88200).apply(original)
>>> resampled.samplerate
88200
>>> abs(resampled.duration - 1) < 0.01
True

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.ChangeSpeed(speed_rate: float, kind: str = 'cubic') → None

Bases: gensound.effect.Effect

Change sound speed effect

Parameters:

• speed_rate (float) – Speed rate of new sound. 1.0 means don’t change speed.
• kind (str) – The way to interpolating data. Please see document of scipy.interpolate.interp1d.

Change sound duration without changes sampling rate.

>>> original = Sound.from_sinwave(440, duration=1, smooth_end=False)
>>> original.duration == 1.0
True

This example changes duration from 1sec to 2sec.

>>> slow = ChangeSpeed(2).apply(original)
>>> slow.duration == 0.5
True

And, changes duration to 0.5sec.

>>> fast = ChangeSpeed(0.5).apply(original)
>>> fast.duration == 2.0
True

Automatically use ReversePlay if speed_rate was lower than 0. >>> ChangeSpeed(-1).apply(original) == ReversePlay().apply(original) True

Sampling rate will not be changed.

>>> original.samplerate == slow.samplerate
True
>>> original.samplerate == fast.samplerate
True

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.ChangeVolume(new_volume: float) → None

Bases: gensound.effect.Effect

Change volume effect

Parameters:new_volume (float) – New target volume. Raises:InvalidVolumeError – Volume was lower than 0 or higher than 1.

This volume means the maximum value of the wave. Please be careful that is not gain.

>>> sound = Sound.from_sinwave(440, volume=1.0)

>>> 0.999 <= sound.data.max() <= 1.0
True
>>> -0.999 >= sound.data.min() >= -1.0
True

>>> half = ChangeVolume(0.5).apply(sound)
>>> 0.499 <= half.volume <= 0.501
True

This effect will return the same instance if given sound had the same volume as the target volume.

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A Sound instance that applied effect.

class gensound.effect.ReversePlay

Bases: gensound.effect.Effect

Reverse play effect

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.

class gensound.effect.Trim(start: typing.Union[float, NoneType] = None, end: typing.Union[float, NoneType] = None) → None

Bases: gensound.effect.Effect

Trim sound

Parameters:

• start (Optional[float]) – The start position of trimming in seconds. If None, won’t trim start side. Default is None.
• end (Optional[float]) – The end position of trimming in seconds. If None, won’t trim end side. Default is None.

Raises:

InvalidDurationError – If start was same or greater than end.

This is alias of Sound.__getitem__.

>>> sound = Sound.from_sinwave(440)

>>> Trim(end=0.5).apply(sound) == sound[:0.5]
True
>>> Trim(start=0.5).apply(sound) == sound[0.5:]
True
>>> Trim(start=0.3, end=0.7).apply(sound) == sound[0.3: 0.7]
True

apply(sound)

Apply effect to sound

Parameters:sound (Sound) – Sound instance to appling effect. Return type:Sound Returns:A new Sound instance that applied effect.