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import torch
from speechbrain.pretrained import Pretrained
class CustomEncoderWav2vec2Classifier(Pretrained):
"""A ready-to-use class for utterance-level classification (e.g, speaker-id,
language-id, emotion recognition, keyword spotting, etc).
The class assumes that an self-supervised encoder like wav2vec2/hubert and a classifier model
are defined in the yaml file. If you want to
convert the predicted index into a corresponding text label, please
provide the path of the label_encoder in a variable called 'lab_encoder_file'
within the yaml.
The class can be used either to run only the encoder (encode_batch()) to
extract embeddings or to run a classification step (classify_batch()).
```
Example
-------
>>> import torchaudio
>>> from speechbrain.pretrained import EncoderClassifier
>>> # Model is downloaded from the speechbrain HuggingFace repo
>>> tmpdir = getfixture("tmpdir")
>>> classifier = EncoderClassifier.from_hparams(
... source="speechbrain/spkrec-ecapa-voxceleb",
... savedir=tmpdir,
... )
>>> # Compute embeddings
>>> signal, fs = torchaudio.load("samples/audio_samples/example1.wav")
>>> embeddings = classifier.encode_batch(signal)
>>> # Classification
>>> prediction = classifier .classify_batch(signal)
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
def encode_batch(self, wavs, wav_lens=None, normalize=False):
"""Encodes the input audio into a single vector embedding.
The waveforms should already be in the model's desired format.
You can call:
``normalized = <this>.normalizer(signal, sample_rate)``
to get a correctly converted signal in most cases.
Arguments
---------
wavs : torch.tensor
Batch of waveforms [batch, time, channels] or [batch, time]
depending on the model. Make sure the sample rate is fs=16000 Hz.
wav_lens : torch.tensor
Lengths of the waveforms relative to the longest one in the
batch, tensor of shape [batch]. The longest one should have
relative length 1.0 and others len(waveform) / max_length.
Used for ignoring padding.
normalize : bool
If True, it normalizes the embeddings with the statistics
contained in mean_var_norm_emb.
Returns
-------
torch.tensor
The encoded batch
"""
# Manage single waveforms in input
if len(wavs.shape) == 1:
wavs = wavs.unsqueeze(0)
# Assign full length if wav_lens is not assigned
if wav_lens is None:
wav_lens = torch.ones(wavs.shape[0], device=self.device)
# Storing waveform in the specified device
wavs, wav_lens = wavs.to(self.device), wav_lens.to(self.device)
wavs = wavs.float()
# Computing features and embeddings
outputs = self.mods.wav2vec2(wavs)
# last dim will be used for AdaptativeAVG pool
outputs = self.mods.avg_pool(outputs, wav_lens)
outputs = outputs.view(outputs.shape[0], -1)
return outputs
def classify_batch(self, wavs, wav_lens=None):
"""Performs classification on the top of the encoded features.
It returns the posterior probabilities, the index and, if the label
encoder is specified it also the text label.
Arguments
---------
wavs : torch.tensor
Batch of waveforms [batch, time, channels] or [batch, time]
depending on the model. Make sure the sample rate is fs=16000 Hz.
wav_lens : torch.tensor
Lengths of the waveforms relative to the longest one in the
batch, tensor of shape [batch]. The longest one should have
relative length 1.0 and others len(waveform) / max_length.
Used for ignoring padding.
Returns
-------
out_prob
The log posterior probabilities of each class ([batch, N_class])
score:
It is the value of the log-posterior for the best class ([batch,])
index
The indexes of the best class ([batch,])
text_lab:
List with the text labels corresponding to the indexes.
(label encoder should be provided).
"""
outputs = self.encode_batch(wavs, wav_lens)
outputs = self.mods.output_mlp(outputs)
out_prob = self.hparams.softmax(outputs)
score, index = torch.max(out_prob, dim=-1)
text_lab = self.hparams.label_encoder.decode_torch(index)
return out_prob, score, index, text_lab
def classify_file(self, path):
"""Classifies the given audiofile into the given set of labels.
Arguments
---------
path : str
Path to audio file to classify.
Returns
-------
out_prob
The log posterior probabilities of each class ([batch, N_class])
score:
It is the value of the log-posterior for the best class ([batch,])
index
The indexes of the best class ([batch,])
text_lab:
List with the text labels corresponding to the indexes.
(label encoder should be provided).
"""
waveform = self.load_audio(path)
# Fake a batch:
batch = waveform.unsqueeze(0)
rel_length = torch.tensor([1.0])
outputs = self.encode_batch(batch, rel_length)
outputs = self.mods.output_mlp(outputs).squeeze(1)
out_prob = self.hparams.softmax(outputs)
score, index = torch.max(out_prob, dim=-1)
text_lab = self.hparams.label_encoder.decode_torch(index)
return out_prob, score, index, text_lab
def forward(self, wavs, wav_lens=None, normalize=False):
return self.encode_batch(
wavs=wavs, wav_lens=wav_lens, normalize=normalize
)
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