forked from k2-fsa/icefall
-
Notifications
You must be signed in to change notification settings - Fork 0
/
pretrained.py
executable file
·266 lines (224 loc) · 7.86 KB
/
pretrained.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
#!/usr/bin/env python3
# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang,
# Wei Kang)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import argparse
import logging
import math
from typing import List
import k2
import kaldifeat
import torch
import torchaudio
from model import TdnnLstm
from torch.nn.utils.rnn import pad_sequence
from icefall.decode import get_lattice, one_best_decoding, rescore_with_whole_lattice
from icefall.utils import AttributeDict, get_texts
def get_parser():
parser = argparse.ArgumentParser(
formatter_class=argparse.ArgumentDefaultsHelpFormatter
)
parser.add_argument(
"--checkpoint",
type=str,
required=True,
help="Path to the checkpoint. "
"The checkpoint is assumed to be saved by "
"icefall.checkpoint.save_checkpoint().",
)
parser.add_argument(
"--words-file",
type=str,
required=True,
help="Path to words.txt",
)
parser.add_argument("--HLG", type=str, required=True, help="Path to HLG.pt.")
parser.add_argument(
"--method",
type=str,
default="1best",
help="""Decoding method.
Possible values are:
(1) 1best - Use the best path as decoding output. Only
the transformer encoder output is used for decoding.
We call it HLG decoding.
(2) whole-lattice-rescoring - Use an LM to rescore the
decoding lattice and then use 1best to decode the
rescored lattice.
We call it HLG decoding + n-gram LM rescoring.
""",
)
parser.add_argument(
"--G",
type=str,
help="""An LM for rescoring.
Used only when method is
whole-lattice-rescoring.
It's usually a 4-gram LM.
""",
)
parser.add_argument(
"--ngram-lm-scale",
type=float,
default=0.8,
help="""
Used only when method is whole-lattice-rescoring.
It specifies the scale for n-gram LM scores.
(Note: You need to tune it on a dataset.)
""",
)
parser.add_argument(
"sound_files",
type=str,
nargs="+",
help="The input sound file(s) to transcribe. "
"Supported formats are those supported by torchaudio.load(). "
"For example, wav and flac are supported. "
"The sample rate has to be 16kHz.",
)
return parser
def get_params() -> AttributeDict:
params = AttributeDict(
{
"feature_dim": 80,
"subsampling_factor": 3,
"num_classes": 72,
"sample_rate": 16000,
"search_beam": 20,
"output_beam": 5,
"min_active_states": 30,
"max_active_states": 10000,
"use_double_scores": True,
}
)
return params
def read_sound_files(
filenames: List[str], expected_sample_rate: float
) -> List[torch.Tensor]:
"""Read a list of sound files into a list 1-D float32 torch tensors.
Args:
filenames:
A list of sound filenames.
expected_sample_rate:
The expected sample rate of the sound files.
Returns:
Return a list of 1-D float32 torch tensors.
"""
ans = []
for f in filenames:
wave, sample_rate = torchaudio.load(f)
assert (
sample_rate == expected_sample_rate
), f"expected sample rate: {expected_sample_rate}. Given: {sample_rate}"
# We use only the first channel
ans.append(wave[0])
return ans
def main():
parser = get_parser()
args = parser.parse_args()
params = get_params()
params.update(vars(args))
logging.info(f"{params}")
device = torch.device("cpu")
if torch.cuda.is_available():
device = torch.device("cuda", 0)
logging.info(f"device: {device}")
logging.info("Creating model")
model = TdnnLstm(
num_features=params.feature_dim,
num_classes=params.num_classes,
subsampling_factor=params.subsampling_factor,
)
checkpoint = torch.load(args.checkpoint, map_location="cpu")
model.load_state_dict(checkpoint["model"])
model.to(device)
model.eval()
logging.info(f"Loading HLG from {params.HLG}")
HLG = k2.Fsa.from_dict(torch.load(params.HLG, map_location="cpu"))
HLG = HLG.to(device)
if not hasattr(HLG, "lm_scores"):
# For whole-lattice-rescoring and attention-decoder
HLG.lm_scores = HLG.scores.clone()
if params.method == "whole-lattice-rescoring":
logging.info(f"Loading G from {params.G}")
G = k2.Fsa.from_dict(torch.load(params.G, map_location="cpu"))
# Add epsilon self-loops to G as we will compose
# it with the whole lattice later
G = G.to(device)
G = k2.add_epsilon_self_loops(G)
G = k2.arc_sort(G)
G.lm_scores = G.scores.clone()
logging.info("Constructing Fbank computer")
opts = kaldifeat.FbankOptions()
opts.device = device
opts.frame_opts.dither = 0
opts.frame_opts.snip_edges = False
opts.frame_opts.samp_freq = params.sample_rate
opts.mel_opts.num_bins = params.feature_dim
fbank = kaldifeat.Fbank(opts)
logging.info(f"Reading sound files: {params.sound_files}")
waves = read_sound_files(
filenames=params.sound_files, expected_sample_rate=params.sample_rate
)
waves = [w.to(device) for w in waves]
logging.info("Decoding started")
features = fbank(waves)
features = pad_sequence(features, batch_first=True, padding_value=math.log(1e-10))
features = features.permute(0, 2, 1) # now features is (N, C, T)
with torch.no_grad():
nnet_output = model(features)
# nnet_output is (N, T, C)
batch_size = nnet_output.shape[0]
supervision_segments = torch.tensor(
[[i, 0, nnet_output.shape[1]] for i in range(batch_size)],
dtype=torch.int32,
)
lattice = get_lattice(
nnet_output=nnet_output,
decoding_graph=HLG,
supervision_segments=supervision_segments,
search_beam=params.search_beam,
output_beam=params.output_beam,
min_active_states=params.min_active_states,
max_active_states=params.max_active_states,
subsampling_factor=params.subsampling_factor,
)
if params.method == "1best":
logging.info("Use HLG decoding")
best_path = one_best_decoding(
lattice=lattice, use_double_scores=params.use_double_scores
)
elif params.method == "whole-lattice-rescoring":
logging.info("Use HLG decoding + LM rescoring")
best_path_dict = rescore_with_whole_lattice(
lattice=lattice,
G_with_epsilon_loops=G,
lm_scale_list=[params.ngram_lm_scale],
)
best_path = next(iter(best_path_dict.values()))
hyps = get_texts(best_path)
word_sym_table = k2.SymbolTable.from_file(params.words_file)
hyps = [[word_sym_table[i] for i in ids] for ids in hyps]
s = "\n"
for filename, hyp in zip(params.sound_files, hyps):
words = " ".join(hyp)
s += f"{filename}:\n{words}\n\n"
logging.info(s)
logging.info("Decoding Done")
if __name__ == "__main__":
formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
logging.basicConfig(format=formatter, level=logging.INFO)
main()