Add pretrained weights for wavernn (#1612)

docs/source/models.rst

@@ -88,8 +88,15 @@ WaveRNN
 
   .. automethod:: forward
 
+Factory Functions
+-----------------
+
+wavernn
+-------
+
+.. autofunction:: wavernn
+
 References
 ~~~~~~~~~~
 
 .. footbibliography::
-

torchaudio/models/__init__.py

 from .wav2letter import Wav2Letter
-from .wavernn import WaveRNN
+from .wavernn import WaveRNN, wavernn
 from .conv_tasnet import ConvTasNet
 from .deepspeech import DeepSpeech
 from .wav2vec2 import (
@@ -13,6 +13,7 @@ from .wav2vec2 import (
 __all__ = [
     'Wav2Letter',
     'WaveRNN',
+    'wavernn',
     'ConvTasNet',
     'DeepSpeech',
     'Wav2Vec2Model',

torchaudio/models/wavernn.py

-from typing import List, Tuple
+from typing import List, Tuple, Dict, Any
 
 import torch
 from torch import Tensor
 from torch import nn
+from torch.hub import load_state_dict_from_url
+
 
 __all__ = [
     "ResBlock",
@@ -10,9 +12,29 @@ __all__ = [
     "Stretch2d",
     "UpsampleNetwork",
     "WaveRNN",
+    "wavernn",
 ]
 
 
+_MODEL_CONFIG_AND_URLS: Dict[str, Tuple[str, Dict[str, Any]]] = {
+    'wavernn_10k_epochs_8bits_ljspeech': (
+        'https://download.pytorch.org/models/audio/wavernn_10k_epochs_8bits_ljspeech.pth',
+        {
+            'upsample_scales': [5, 5, 11],
+            'n_classes': 2 ** 8,  # n_bits = 8
+            'hop_length': 275,
+            'n_res_block': 10,
+            'n_rnn': 512,
+            'n_fc': 512,
+            'kernel_size': 5,
+            'n_freq': 80,
+            'n_hidden': 128,
+            'n_output': 128
+        }
+    )
+}
+
+
 class ResBlock(nn.Module):
     r"""ResNet block based on *Efficient Neural Audio Synthesis* [:footcite:`kalchbrenner2018efficient`].
 
@@ -324,3 +346,28 @@ class WaveRNN(nn.Module):
 
         # bring back channel dimension
         return x.unsqueeze(1)
+
+
+def wavernn(checkpoint_name: str) -> WaveRNN:
+    r"""Get pretrained WaveRNN model.
+
+    Args:
+        checkpoint_name (str): The name of the checkpoint to load. Available checkpoints:
+
+            - ``"wavernn_10k_epochs_8bits_ljspeech"``:
+
+                WaveRNN model trained with 10k epochs and 8 bits depth waveform on the LJSpeech dataset.
+                The model is trained using the default parameters and code of the
+                `examples/pipeline_wavernn/main.py
+                <https://github.com/pytorch/audio/tree/master/examples/pipeline_wavernn>`_.
+    """
+    if checkpoint_name not in _MODEL_CONFIG_AND_URLS:
+        raise ValueError(
+            f"Unexpected checkpoint_name: '{checkpoint_name}'. "
+            f"Valid choices are; {list(_MODEL_CONFIG_AND_URLS.keys())}")
+
+    url, configs = _MODEL_CONFIG_AND_URLS[checkpoint_name]
+    model = WaveRNN(**configs)
+    state_dict = load_state_dict_from_url(url, progress=False)
+    model.load_state_dict(state_dict)
+    return model