add augmentor class

deep_speech_2/data_utils/audio.py

@@ -308,7 +308,7 @@ class AudioSegment(object):
         prior_mean_squared = 10.**(prior_db / 10.)
         prior_sum_of_squares = prior_mean_squared * prior_samples
         cumsum_of_squares = np.cumsum(self.samples**2)
-        sample_count = np.arange(len(self.num_samples)) + 1
+        sample_count = np.arange(self.num_samples) + 1
         if startup_sample_idx > 0:
             cumsum_of_squares[:startup_sample_idx] = \
                 cumsum_of_squares[startup_sample_idx]

deep_speech_2/data_utils/augmentor/augmentation.py

@@ -6,6 +6,9 @@ from __future__ import print_function
 import json
 import random
 from data_utils.augmentor.volume_perturb import VolumePerturbAugmentor
+from data_utils.augmentor.speed_perturb import SpeedPerturbAugmentor
+from data_utils.augmentor.resample import ResampleAugmentor
+from data_utils.augmentor.online_bayesian_normalization import OnlineBayesianNormalizationAugmentor
 
 
 class AugmentationPipeline(object):
@@ -76,5 +79,11 @@ class AugmentationPipeline(object):
         """Return an augmentation model by the type name, and pass in params."""
         if augmentor_type == "volume":
             return VolumePerturbAugmentor(self._rng, **params)
+        if augmentor_type == "speed":
+            return SpeedPerturbAugmentor(self._rng, **params)
+        if augmentor_type == "resample":
+            return ResampleAugmentor(self._rng, **params)
+        if augmentor_type == "baysian_normal":
+            return OnlineBayesianNormalizationAugmentor(self._rng, **params)
         else:
             raise ValueError("Unknown augmentor type [%s]." % augmentor_type)

deep_speech_2/data_utils/augmentor/online_bayesian_normalization.py

+"""Contain the online bayesian normalization augmentation model."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from data_utils.augmentor.base import AugmentorBase
+
+
+class OnlineBayesianNormalizationAugmentor(AugmentorBase):
+    """Augmentation model for adding online bayesian normalization.
+
+    :param rng: Random generator object.
+    :type rng: random.Random
+    :param target_db: Target RMS value in decibels.
+    :type target_db: float
+    :param prior_db: Prior RMS estimate in decibels.
+    :type prior_db: float
+    :param prior_samples: Prior strength in number of samples.
+    :type prior_samples: int
+    :param startup_delay: Default 0.0s. If provided, this function will
+                          accrue statistics for the first startup_delay 
+                          seconds before applying online normalization.
+    :type starup_delay: float.
+    """
+
+    def __init__(self,
+                 rng,
+                 target_db,
+                 prior_db,
+                 prior_samples,
+                 startup_delay=0.0):
+        self._target_db = target_db
+        self._prior_db = prior_db
+        self._prior_samples = prior_samples
+        self._startup_delay = startup_delay
+        self._rng = rng
+        self._startup_delay=startup_delay
+
+    def transform_audio(self, audio_segment):
+        """Normalizes the input audio using the online Bayesian approach.
+
+        Note that this is an in-place transformation.
+
+        :param audio_segment: Audio segment to add effects to.
+        :type audio_segment: AudioSegment|SpeechSegment
+        """
+        audio_segment.normalize_online_bayesian(self._target_db,
+                                                self._prior_db,
+                                                self._prior_samples,
+                                                self._startup_delay)

deep_speech_2/data_utils/augmentor/resample.py

+"""Contain the resample augmentation model."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from data_utils.augmentor.base import AugmentorBase
+
+
+class ResampleAugmentor(AugmentorBase):
+    """Augmentation model for resampling.
+    
+    :param rng: Random generator object.
+    :type rng: random.Random
+    :param new_sample_rate: New sample rate in Hz
+    :type new_sample_rate: int
+    """
+
+    def __init__(self, rng, new_sample_rate):
+        self._new_sample_rate = new_sample_rate
+        self._rng = rng
+
+    def transform_audio(self, audio_segment):
+        """Resamples the input audio to a target sample rate.
+
+        Note that this is an in-place transformation.
+
+        :param audio: Audio segment to add effects to.
+        :type audio: AudioSegment|SpeechSegment
+        """
+        audio_segment.resample(self._new_sample_rate)
\ No newline at end of file

deep_speech_2/data_utils/augmentor/speed_perturb.py

+"""Contain the speech perturbation augmentation model."""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from data_utils.augmentor.base import AugmentorBase
+
+
+class SpeedPerturbAugmentor(AugmentorBase):
+    """Augmentation model for adding speed perturbation.
+
+    See reference paper here:
+    http://www.danielpovey.com/files/2015_interspeech_augmentation.pdf
+
+    :param rng: Random generator object.
+    :type rng: random.Random
+    :param min_speed_rate: Lower bound of new speed rate to sample.
+    :type min_speed_rate: float
+    :param max_speed_rate: Upper bound of new speed rate to sample.
+    :type max_speed_rate: float
+    """
+
+    def __init__(self, rng, min_speed_rate, max_speed_rate):
+
+        if (min_speed_rate < 0.5):
+            raise ValueError("Sampling speed below 0.9 can cause unnatural effects")
+        if (max_speed_rate > 1.5):
+            raise ValueError("Sampling speed above 1.1 can cause unnatural effects")
+        self._min_speed_rate = min_speed_rate
+        self._max_speed_rate = max_speed_rate
+        self._rng = rng
+
+    def transform_audio(self, audio_segment):
+        """Sample a new speed rate from the given range and
+        changes the speed of the given audio clip.
+
+        Note that this is an in-place transformation.
+
+        :param audio_segment: Audio segment to add effects to.
+        :type audio_segment: AudioSegment|SpeechSegment
+        """
+        sampled_speed = self._rng.uniform(self._min_speed_rate, self._max_speed_rate)
+        audio_segment.change_speed(sampled_speed)

deep_speech_2/data_utils/augmentor/volume_perturb.py

@@ -36,5 +36,5 @@ class VolumePerturbAugmentor(AugmentorBase):
         :param audio_segment: Audio segment to add effects to.
         :type audio_segment: AudioSegmenet|SpeechSegment
         """
-        gain = self._rng.uniform(min_gain_dBFS, max_gain_dBFS)
+        gain = self._rng.uniform(self._min_gain_dBFS, self._max_gain_dBFS)
         audio_segment.apply_gain(gain)