Update perturb.py (NVIDIA#5231)

* Update perturb.py

Add checking for channels mismatch for audio and noise data, throw an exception if they have different number of channels. Also fixed `perturb_with_foreground_noise` as done in `perturb_with_input_noise` 

Signed-off-by: He Huang (Steve) <[email protected]>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* update check and teest

Signed-off-by: stevehuang52 <[email protected]>

* fix test

Signed-off-by: stevehuang52 <[email protected]>

Signed-off-by: He Huang (Steve) <[email protected]>
Signed-off-by: stevehuang52 <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Signed-off-by: Hainan Xu <[email protected]>

nemo/collections/asr/parts/preprocessing/perturb.py

@@ -432,6 +432,11 @@ def get_one_noise_sample(self, target_sr):
         )
 
     def perturb(self, data, ref_mic=0):
+        """
+        Args:
+            data (AudioSegment): audio data
+            ref_mic (int): reference mic index for scaling multi-channel audios
+        """
         noise = read_one_audiosegment(
             self._manifest,
             data.sample_rate,
@@ -442,6 +447,23 @@ def perturb(self, data, ref_mic=0):
         self.perturb_with_input_noise(data, noise, ref_mic=ref_mic)
 
     def perturb_with_input_noise(self, data, noise, data_rms=None, ref_mic=0):
+        """
+        Args:
+            data (AudioSegment): audio data
+            noise (AudioSegment): noise data
+            data_rms (Union[float, List[float]): rms_db for data input
+            ref_mic (int): reference mic index for scaling multi-channel audios
+        """
+        if data.num_channels != noise.num_channels:
+            raise ValueError(
+                f"Found mismatched channels for data ({data.num_channels}) and noise ({noise.num_channels})."
+            )
+
+        if not (0 <= ref_mic < data.num_channels):
+            raise ValueError(
+                f" reference mic ID must be an integer in [0, {data.num_channels}), got {ref_mic} instead."
+            )
+
         snr_db = self._rng.uniform(self._min_snr_db, self._max_snr_db)
         if data_rms is None:
             data_rms = data.rms_db
@@ -467,14 +489,36 @@ def perturb_with_input_noise(self, data, noise, data_rms=None, ref_mic=0):
         else:
             data._samples += noise._samples
 
-    def perturb_with_foreground_noise(
-        self, data, noise, data_rms=None, max_noise_dur=2, max_additions=1,
-    ):
+    def perturb_with_foreground_noise(self, data, noise, data_rms=None, max_noise_dur=2, max_additions=1, ref_mic=0):
+        """
+        Args:
+            data (AudioSegment): audio data
+            noise (AudioSegment): noise data
+            data_rms (Union[float, List[float]): rms_db for data input
+            max_noise_dur: (float): max noise duration
+            max_additions (int): number of times for adding noise
+            ref_mic (int): reference mic index for scaling multi-channel audios
+        """
+        if data.num_channels != noise.num_channels:
+            raise ValueError(
+                f"Found mismatched channels for data ({data.num_channels}) and noise ({noise.num_channels})."
+            )
+
+        if not (0 <= ref_mic < data.num_channels):
+            raise ValueError(
+                f" reference mic ID must be an integer in [0, {data.num_channels}), got {ref_mic} instead."
+            )
+
         snr_db = self._rng.uniform(self._min_snr_db, self._max_snr_db)
         if not data_rms:
             data_rms = data.rms_db
 
-        noise_gain_db = min(data_rms - noise.rms_db - snr_db, self._max_gain_db)
+        if data.num_channels > 1:
+            noise_gain_db = data_rms[ref_mic] - noise.rms_db[ref_mic] - snr_db
+        else:
+            noise_gain_db = data_rms - noise.rms_db - snr_db
+        noise_gain_db = min(noise_gain_db, self._max_gain_db)
+
         n_additions = self._rng.randint(1, max_additions)
 
         for i in range(n_additions):

tests/collections/asr/test_preprocessing_segment.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import os
 import tempfile
 from typing import List, Type, Union
@@ -20,6 +21,7 @@
 import pytest
 import soundfile as sf
 
+from nemo.collections.asr.parts.preprocessing.perturb import NoisePerturbation
 from nemo.collections.asr.parts.preprocessing.segment import AudioSegment
 from nemo.collections.asr.parts.utils.audio_utils import select_channels
 
@@ -120,3 +122,58 @@ def test_from_file(self, num_channels, channel_selector):
             assert uut.duration == self.signal_duration_sec
             max_diff = np.max(np.abs(uut.samples - golden_samples))
             assert max_diff < self.max_diff_tol
+
+    @pytest.mark.unit
+    @pytest.mark.parametrize("data_channels", [1, 4])
+    @pytest.mark.parametrize("noise_channels", [1, 4])
+    def test_noise_perturb_channels(self, data_channels, noise_channels):
+        """Test loading a signal from a file.
+        """
+        with tempfile.TemporaryDirectory() as test_dir:
+            # Prepare a wav file
+            audio_file = os.path.join(test_dir, 'audio.wav')
+            if data_channels == 1:
+                # samples is a one-dimensional vector for single-channel signal
+                samples = np.random.rand(self.num_samples)
+            else:
+                samples = np.random.rand(self.num_samples, data_channels)
+            sf.write(audio_file, samples, self.sample_rate, 'float')
+
+            noise_file = os.path.join(test_dir, 'noise.wav')
+            if noise_channels == 1:
+                # samples is a one-dimensional vector for single-channel signal
+                samples = np.random.rand(self.num_samples)
+            else:
+                samples = np.random.rand(self.num_samples, noise_channels)
+            sf.write(noise_file, samples, self.sample_rate, 'float')
+
+            manifest_file = os.path.join(test_dir, 'noise_manifest.json')
+            with open(manifest_file, 'w') as fout:
+                item = {'audio_filepath': os.path.abspath(noise_file), 'label': '-', 'duration': 0.1, 'offset': 0.0}
+                fout.write(f'{json.dumps(item)}\n')
+
+            perturber = NoisePerturbation(manifest_file)
+            audio = AudioSegment.from_file(audio_file)
+            noise = AudioSegment.from_file(noise_file)
+
+            if data_channels == noise_channels:
+                try:
+                    _ = perturber.perturb_with_input_noise(audio, noise, ref_mic=0)
+                except ValueError as e:
+                    assert False, "perturb_with_input_noise failed with ref_mic=0"
+
+                with pytest.raises(ValueError):
+                    _ = perturber.perturb_with_input_noise(audio, noise, ref_mic=data_channels)
+
+                try:
+                    _ = perturber.perturb_with_foreground_noise(audio, noise, ref_mic=0)
+                except ValueError as e:
+                    assert False, "perturb_with_foreground_noise failed with ref_mic=0"
+
+                with pytest.raises(ValueError):
+                    _ = perturber.perturb_with_foreground_noise(audio, noise, ref_mic=data_channels)
+            else:
+                with pytest.raises(ValueError):
+                    _ = perturber.perturb_with_input_noise(audio, noise)
+                with pytest.raises(ValueError):
+                    _ = perturber.perturb_with_foreground_noise(audio, noise)