2025-07-10 15:27:08 +08:00

323 lines
8.9 KiB
Python
Executable File

#!/usr/bin/env python3
# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang)
#
# 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.
"""
Usage:
(1) greedy search
./transducer_stateless/pretrained.py \
--checkpoint ./transducer_stateless/exp/pretrained.pt \
--bpe-model ./data/lang_bpe_500/bpe.model \
--method greedy_search \
/path/to/foo.wav \
/path/to/bar.wav \
(1) beam search
./transducer_stateless/pretrained.py \
--checkpoint ./transducer_stateless/exp/pretrained.pt \
--bpe-model ./data/lang_bpe_500/bpe.model \
--method beam_search \
--beam-size 4 \
/path/to/foo.wav \
/path/to/bar.wav \
You can also use `./transducer_stateless/exp/epoch-xx.pt`.
Note: ./transducer_stateless/exp/pretrained.pt is generated by
./transducer_stateless/export.py
"""
import argparse
import logging
import math
from pathlib import Path
from typing import List
import kaldifeat
import torch
import torch.nn as nn
import torchaudio
from beam_search import beam_search, greedy_search
from conformer import Conformer
from decoder import Decoder
from joiner import Joiner
from model import Transducer
from torch.nn.utils.rnn import pad_sequence
from icefall.char_graph_compiler import CharCtcTrainingGraphCompiler
from icefall.env import get_env_info
from icefall.lexicon import Lexicon
from icefall.utils import AttributeDict
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(
"--lang-dir",
type=str,
help="""Path to lang.
Used only when method is ctc-decoding.
""",
)
parser.add_argument(
"--method",
type=str,
default="greedy_search",
help="""Possible values are:
- greedy_search
- beam_search
""",
)
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.",
)
parser.add_argument(
"--beam-size",
type=int,
default=4,
help="Used only when --method is beam_search",
)
parser.add_argument(
"--context-size",
type=int,
default=2,
help="The context size in the decoder. 1 means bigram; 2 means tri-gram",
)
parser.add_argument(
"--max-sym-per-frame",
type=int,
default=3,
help="""Maximum number of symbols per frame. Used only when
--method is greedy_search.
""",
)
return parser
def get_params() -> AttributeDict:
params = AttributeDict(
{
"sample_rate": 16000,
# parameters for conformer
"feature_dim": 80,
"encoder_out_dim": 512,
"subsampling_factor": 4,
"attention_dim": 512,
"nhead": 8,
"dim_feedforward": 2048,
"num_encoder_layers": 12,
"vgg_frontend": False,
"env_info": get_env_info(),
}
)
return params
def get_encoder_model(params: AttributeDict) -> nn.Module:
encoder = Conformer(
num_features=params.feature_dim,
output_dim=params.encoder_out_dim,
subsampling_factor=params.subsampling_factor,
d_model=params.attention_dim,
nhead=params.nhead,
dim_feedforward=params.dim_feedforward,
num_encoder_layers=params.num_encoder_layers,
vgg_frontend=params.vgg_frontend,
)
return encoder
def get_decoder_model(params: AttributeDict) -> nn.Module:
decoder = Decoder(
vocab_size=params.vocab_size,
embedding_dim=params.encoder_out_dim,
blank_id=params.blank_id,
context_size=params.context_size,
)
return decoder
def get_joiner_model(params: AttributeDict) -> nn.Module:
joiner = Joiner(
input_dim=params.encoder_out_dim,
output_dim=params.vocab_size,
)
return joiner
def get_transducer_model(params: AttributeDict) -> nn.Module:
encoder = get_encoder_model(params)
decoder = get_decoder_model(params)
joiner = get_joiner_model(params)
model = Transducer(
encoder=encoder,
decoder=decoder,
joiner=joiner,
)
return model
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()
args.lang_dir = Path(args.lang_dir)
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}")
lexicon = Lexicon(params.lang_dir)
graph_compiler = CharCtcTrainingGraphCompiler(
lexicon=lexicon,
device=device,
)
params.blank_id = graph_compiler.texts_to_ids("<blk>")[0][0]
params.vocab_size = max(lexicon.tokens) + 1
logging.info("Creating model")
model = get_transducer_model(params)
checkpoint = torch.load(args.checkpoint, map_location="cpu", weights_only=False)
model.load_state_dict(checkpoint["model"], strict=False)
model.to(device)
model.eval()
model.device = device
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
opts.mel_opts.high_freq = -400
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)
feature_lengths = [f.size(0) for f in features]
features = pad_sequence(features, batch_first=True, padding_value=math.log(1e-10))
feature_lengths = torch.tensor(feature_lengths, device=device)
with torch.no_grad():
encoder_out, encoder_out_lens = model.encoder(
x=features, x_lens=feature_lengths
)
num_waves = encoder_out.size(0)
hyps = []
msg = f"Using {params.method}"
if params.method == "beam_search":
msg += f" with beam size {params.beam_size}"
logging.info(msg)
for i in range(num_waves):
# fmt: off
encoder_out_i = encoder_out[i:i+1, :encoder_out_lens[i]]
# fmt: on
if params.method == "greedy_search":
hyp = greedy_search(
model=model,
encoder_out=encoder_out_i,
max_sym_per_frame=params.max_sym_per_frame,
)
elif params.method == "beam_search":
hyp = beam_search(
model=model, encoder_out=encoder_out_i, beam=params.beam_size
)
else:
raise ValueError(f"Unsupported method: {params.method}")
hyps.append([lexicon.token_table[i] for i in hyp])
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()