from typing import Optional, Tuple, Union
from lhotse import CutSet
from lhotse.utils import Decibels
[docs]class CutMix:
"""
A transform for batches of cuts (CutSet's) that stochastically performs
noise augmentation with a constant or varying SNR.
"""
[docs] def __init__(
self,
cuts: CutSet,
snr: Optional[Union[Decibels, Tuple[Decibels, Decibels]]] = (10, 20),
prob: float = 0.5,
pad_to_longest: bool = True
) -> None:
"""
CutMix's constructor.
:param cuts: a ``CutSet`` containing augmentation data, e.g. noise, music, babble.
:param snr: either a float, a pair (range) of floats, or ``None``.
It determines the SNR of the speech signal vs the noise signal that's mixed into it.
When a range is specified, we will uniformly sample SNR in that range.
When it's ``None``, the noise will be mixed as-is -- i.e. without any level adjustment.
Note that it's different from ``snr=0``, which will adjust the noise level so that the SNR is 0.
:param prob: a float probability in range [0, 1].
Specifies the probability with which we will mix augment the cuts.
:param pad_to_longest: when `True`, each processed :class:`CutSet` will be padded with noise
to match the duration of the longest Cut in a batch.
"""
self.cuts = cuts
self.snr = snr
self.prob = prob
self.pad_to_longest = pad_to_longest
def __call__(self, cuts: CutSet) -> CutSet:
maybe_max_duration = max(c.duration for c in cuts) if self.pad_to_longest else None
return cuts.mix(
cuts=self.cuts,
duration=maybe_max_duration,
snr=self.snr,
mix_prob=self.prob
)