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enginex_bi_series-sherpa-onnx/python-api-examples/offline-decode-files.py
Askars Salimbajevs f0960342ad Add LODR support to online and offline recognizers (#2026)
This PR integrates LODR (Level-Ordered Deterministic Rescoring) support from Icefall into both online and offline recognizers, enabling LODR for LM shallow fusion and LM rescore.

- Extended OnlineLMConfig and OfflineLMConfig to include lodr_fst, lodr_scale, and lodr_backoff_id.
- Implemented LodrFst and LodrStateCost classes and wired them into RNN LM scoring in both online and offline code paths.
- Updated Python bindings, CLI entry points, examples, and CI test scripts to accept and exercise the new LODR options.
2025-07-09 16:23:46 +08:00

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Python
Executable File

#!/usr/bin/env python3
#
# Copyright (c) 2023 by manyeyes
# Copyright (c) 2023 Xiaomi Corporation
"""
This file demonstrates how to use sherpa-onnx Python API to transcribe
file(s) with a non-streaming model.
(1) For paraformer
./python-api-examples/offline-decode-files.py \
--tokens=/path/to/tokens.txt \
--paraformer=/path/to/paraformer.onnx \
--num-threads=2 \
--decoding-method=greedy_search \
--debug=false \
--sample-rate=16000 \
--feature-dim=80 \
/path/to/0.wav \
/path/to/1.wav
(2) For transducer models from icefall
./python-api-examples/offline-decode-files.py \
--tokens=/path/to/tokens.txt \
--encoder=/path/to/encoder.onnx \
--decoder=/path/to/decoder.onnx \
--joiner=/path/to/joiner.onnx \
--num-threads=2 \
--decoding-method=greedy_search \
--debug=false \
--sample-rate=16000 \
--feature-dim=80 \
/path/to/0.wav \
/path/to/1.wav
also with RNN LM rescoring and LODR (optional):
./python-api-examples/offline-decode-files.py \
--tokens=/path/to/tokens.txt \
--encoder=/path/to/encoder.onnx \
--decoder=/path/to/decoder.onnx \
--joiner=/path/to/joiner.onnx \
--num-threads=2 \
--decoding-method=modified_beam_search \
--debug=false \
--sample-rate=16000 \
--feature-dim=80 \
--lm=/path/to/lm.onnx \
--lm-scale=0.1 \
--lodr-fst=/path/to/lodr.fst \
--lodr-scale=-0.1 \
/path/to/0.wav \
/path/to/1.wav
(3) For CTC models from NeMo
python3 ./python-api-examples/offline-decode-files.py \
--tokens=./sherpa-onnx-nemo-ctc-en-citrinet-512/tokens.txt \
--nemo-ctc=./sherpa-onnx-nemo-ctc-en-citrinet-512/model.onnx \
--num-threads=2 \
--decoding-method=greedy_search \
--debug=false \
./sherpa-onnx-nemo-ctc-en-citrinet-512/test_wavs/0.wav \
./sherpa-onnx-nemo-ctc-en-citrinet-512/test_wavs/1.wav \
./sherpa-onnx-nemo-ctc-en-citrinet-512/test_wavs/8k.wav
(4) For Whisper models
python3 ./python-api-examples/offline-decode-files.py \
--whisper-encoder=./sherpa-onnx-whisper-base.en/base.en-encoder.int8.onnx \
--whisper-decoder=./sherpa-onnx-whisper-base.en/base.en-decoder.int8.onnx \
--tokens=./sherpa-onnx-whisper-base.en/base.en-tokens.txt \
--whisper-task=transcribe \
--num-threads=1 \
./sherpa-onnx-whisper-base.en/test_wavs/0.wav \
./sherpa-onnx-whisper-base.en/test_wavs/1.wav \
./sherpa-onnx-whisper-base.en/test_wavs/8k.wav
(5) For CTC models from WeNet
python3 ./python-api-examples/offline-decode-files.py \
--wenet-ctc=./sherpa-onnx-zh-wenet-wenetspeech/model.onnx \
--tokens=./sherpa-onnx-zh-wenet-wenetspeech/tokens.txt \
./sherpa-onnx-zh-wenet-wenetspeech/test_wavs/0.wav \
./sherpa-onnx-zh-wenet-wenetspeech/test_wavs/1.wav \
./sherpa-onnx-zh-wenet-wenetspeech/test_wavs/8k.wav
(6) For tdnn models of the yesno recipe from icefall
python3 ./python-api-examples/offline-decode-files.py \
--sample-rate=8000 \
--feature-dim=23 \
--tdnn-model=./sherpa-onnx-tdnn-yesno/model-epoch-14-avg-2.onnx \
--tokens=./sherpa-onnx-tdnn-yesno/tokens.txt \
./sherpa-onnx-tdnn-yesno/test_wavs/0_0_0_1_0_0_0_1.wav \
./sherpa-onnx-tdnn-yesno/test_wavs/0_0_1_0_0_0_1_0.wav \
./sherpa-onnx-tdnn-yesno/test_wavs/0_0_1_0_0_1_1_1.wav
Please refer to
https://k2-fsa.github.io/sherpa/onnx/index.html
to install sherpa-onnx and to download non-streaming pre-trained models
used in this file.
"""
import argparse
import time
import wave
from pathlib import Path
from typing import List, Tuple
import numpy as np
import sherpa_onnx
def get_args():
parser = argparse.ArgumentParser(
formatter_class=argparse.ArgumentDefaultsHelpFormatter
)
parser.add_argument(
"--tokens",
type=str,
help="Path to tokens.txt",
)
parser.add_argument(
"--hotwords-file",
type=str,
default="",
help="""
The file containing hotwords, one words/phrases per line, like
HELLO WORLD
你好世界
""",
)
parser.add_argument(
"--hotwords-score",
type=float,
default=1.5,
help="""
The hotword score of each token for biasing word/phrase. Used only if
--hotwords-file is given.
""",
)
parser.add_argument(
"--modeling-unit",
type=str,
default="",
help="""
The modeling unit of the model, valid values are cjkchar, bpe, cjkchar+bpe.
Used only when hotwords-file is given.
""",
)
parser.add_argument(
"--bpe-vocab",
type=str,
default="",
help="""
The path to the bpe vocabulary, the bpe vocabulary is generated by
sentencepiece, you can also export the bpe vocabulary through a bpe model
by `scripts/export_bpe_vocab.py`. Used only when hotwords-file is given
and modeling-unit is bpe or cjkchar+bpe.
""",
)
parser.add_argument(
"--encoder",
default="",
type=str,
help="Path to the encoder model",
)
parser.add_argument(
"--decoder",
default="",
type=str,
help="Path to the decoder model",
)
parser.add_argument(
"--joiner",
default="",
type=str,
help="Path to the joiner model",
)
parser.add_argument(
"--paraformer",
default="",
type=str,
help="Path to the model.onnx from Paraformer",
)
parser.add_argument(
"--nemo-ctc",
default="",
type=str,
help="Path to the model.onnx from NeMo CTC",
)
parser.add_argument(
"--wenet-ctc",
default="",
type=str,
help="Path to the model.onnx from WeNet CTC",
)
parser.add_argument(
"--tdnn-model",
default="",
type=str,
help="Path to the model.onnx for the tdnn model of the yesno recipe",
)
parser.add_argument(
"--num-threads",
type=int,
default=1,
help="Number of threads for neural network computation",
)
parser.add_argument(
"--whisper-encoder",
default="",
type=str,
help="Path to whisper encoder model",
)
parser.add_argument(
"--whisper-decoder",
default="",
type=str,
help="Path to whisper decoder model",
)
parser.add_argument(
"--whisper-language",
default="",
type=str,
help="""It specifies the spoken language in the input audio file.
Example values: en, fr, de, zh, jp.
Available languages for multilingual models can be found at
https://github.com/openai/whisper/blob/main/whisper/tokenizer.py#L10
If not specified, we infer the language from the input audio file.
""",
)
parser.add_argument(
"--whisper-task",
default="transcribe",
choices=["transcribe", "translate"],
type=str,
help="""For multilingual models, if you specify translate, the output
will be in English.
""",
)
parser.add_argument(
"--whisper-tail-paddings",
default=-1,
type=int,
help="""Number of tail padding frames.
We have removed the 30-second constraint from whisper, so you need to
choose the amount of tail padding frames by yourself.
Use -1 to use a default value for tail padding.
""",
)
parser.add_argument(
"--blank-penalty",
type=float,
default=0.0,
help="""
The penalty applied on blank symbol during decoding.
Note: It is a positive value that would be applied to logits like
this `logits[:, 0] -= blank_penalty` (suppose logits.shape is
[batch_size, vocab] and blank id is 0).
""",
)
parser.add_argument(
"--decoding-method",
type=str,
default="greedy_search",
help="Valid values are greedy_search and modified_beam_search",
)
parser.add_argument(
"--lm",
metavar="file",
type=str,
default="",
help="Path to RNN LM model",
)
parser.add_argument(
"--lm-scale",
metavar="lm_scale",
type=float,
default=0.1,
help="LM model scale for rescoring",
)
parser.add_argument(
"--lodr-fst",
metavar="file",
type=str,
default="",
help="Path to LODR FST model. Used only when --lm is given.",
)
parser.add_argument(
"--lodr-scale",
metavar="lodr_scale",
type=float,
default=-0.1,
help="LODR scale for rescoring.Used only when --lodr_fst is given.",
)
parser.add_argument(
"--debug",
type=bool,
default=False,
help="True to show debug messages",
)
parser.add_argument(
"--sample-rate",
type=int,
default=16000,
help="""Sample rate of the feature extractor. Must match the one
expected by the model. Note: The input sound files can have a
different sample rate from this argument.""",
)
parser.add_argument(
"--feature-dim",
type=int,
default=80,
help="Feature dimension. Must match the one expected by the model",
)
parser.add_argument(
"sound_files",
type=str,
nargs="+",
help="The input sound file(s) to decode. Each file must be of WAVE"
"format with a single channel, and each sample has 16-bit, "
"i.e., int16_t. "
"The sample rate of the file can be arbitrary and does not need to "
"be 16 kHz",
)
return parser.parse_args()
def assert_file_exists(filename: str):
assert Path(filename).is_file(), (
f"{filename} does not exist!\n"
"Please refer to "
"https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html to download it"
)
def read_wave(wave_filename: str) -> Tuple[np.ndarray, int]:
"""
Args:
wave_filename:
Path to a wave file. It should be single channel and each sample should
be 16-bit. Its sample rate does not need to be 16kHz.
Returns:
Return a tuple containing:
- A 1-D array of dtype np.float32 containing the samples, which are
normalized to the range [-1, 1].
- sample rate of the wave file
"""
with wave.open(wave_filename) as f:
assert f.getnchannels() == 1, f.getnchannels()
assert f.getsampwidth() == 2, f.getsampwidth() # it is in bytes
num_samples = f.getnframes()
samples = f.readframes(num_samples)
samples_int16 = np.frombuffer(samples, dtype=np.int16)
samples_float32 = samples_int16.astype(np.float32)
samples_float32 = samples_float32 / 32768
return samples_float32, f.getframerate()
def main():
args = get_args()
assert_file_exists(args.tokens)
assert args.num_threads > 0, args.num_threads
if args.encoder:
assert len(args.paraformer) == 0, args.paraformer
assert len(args.nemo_ctc) == 0, args.nemo_ctc
assert len(args.wenet_ctc) == 0, args.wenet_ctc
assert len(args.whisper_encoder) == 0, args.whisper_encoder
assert len(args.whisper_decoder) == 0, args.whisper_decoder
assert len(args.tdnn_model) == 0, args.tdnn_model
assert_file_exists(args.encoder)
assert_file_exists(args.decoder)
assert_file_exists(args.joiner)
recognizer = sherpa_onnx.OfflineRecognizer.from_transducer(
encoder=args.encoder,
decoder=args.decoder,
joiner=args.joiner,
tokens=args.tokens,
num_threads=args.num_threads,
sample_rate=args.sample_rate,
feature_dim=args.feature_dim,
lm=args.lm,
lm_scale=args.lm_scale,
lodr_fst=args.lodr_fst,
lodr_scale=args.lodr_scale,
decoding_method=args.decoding_method,
hotwords_file=args.hotwords_file,
hotwords_score=args.hotwords_score,
modeling_unit=args.modeling_unit,
bpe_vocab=args.bpe_vocab,
blank_penalty=args.blank_penalty,
debug=args.debug,
)
elif args.paraformer:
assert len(args.nemo_ctc) == 0, args.nemo_ctc
assert len(args.wenet_ctc) == 0, args.wenet_ctc
assert len(args.whisper_encoder) == 0, args.whisper_encoder
assert len(args.whisper_decoder) == 0, args.whisper_decoder
assert len(args.tdnn_model) == 0, args.tdnn_model
assert_file_exists(args.paraformer)
recognizer = sherpa_onnx.OfflineRecognizer.from_paraformer(
paraformer=args.paraformer,
tokens=args.tokens,
num_threads=args.num_threads,
sample_rate=args.sample_rate,
feature_dim=args.feature_dim,
decoding_method=args.decoding_method,
debug=args.debug,
)
elif args.nemo_ctc:
assert len(args.wenet_ctc) == 0, args.wenet_ctc
assert len(args.whisper_encoder) == 0, args.whisper_encoder
assert len(args.whisper_decoder) == 0, args.whisper_decoder
assert len(args.tdnn_model) == 0, args.tdnn_model
assert_file_exists(args.nemo_ctc)
recognizer = sherpa_onnx.OfflineRecognizer.from_nemo_ctc(
model=args.nemo_ctc,
tokens=args.tokens,
num_threads=args.num_threads,
sample_rate=args.sample_rate,
feature_dim=args.feature_dim,
decoding_method=args.decoding_method,
debug=args.debug,
)
elif args.wenet_ctc:
assert len(args.whisper_encoder) == 0, args.whisper_encoder
assert len(args.whisper_decoder) == 0, args.whisper_decoder
assert len(args.tdnn_model) == 0, args.tdnn_model
assert_file_exists(args.wenet_ctc)
recognizer = sherpa_onnx.OfflineRecognizer.from_wenet_ctc(
model=args.wenet_ctc,
tokens=args.tokens,
num_threads=args.num_threads,
sample_rate=args.sample_rate,
feature_dim=args.feature_dim,
decoding_method=args.decoding_method,
debug=args.debug,
)
elif args.whisper_encoder:
assert len(args.tdnn_model) == 0, args.tdnn_model
assert_file_exists(args.whisper_encoder)
assert_file_exists(args.whisper_decoder)
recognizer = sherpa_onnx.OfflineRecognizer.from_whisper(
encoder=args.whisper_encoder,
decoder=args.whisper_decoder,
tokens=args.tokens,
num_threads=args.num_threads,
decoding_method=args.decoding_method,
debug=args.debug,
language=args.whisper_language,
task=args.whisper_task,
tail_paddings=args.whisper_tail_paddings,
)
elif args.tdnn_model:
assert_file_exists(args.tdnn_model)
recognizer = sherpa_onnx.OfflineRecognizer.from_tdnn_ctc(
model=args.tdnn_model,
tokens=args.tokens,
sample_rate=args.sample_rate,
feature_dim=args.feature_dim,
num_threads=args.num_threads,
decoding_method=args.decoding_method,
debug=args.debug,
)
else:
print("Please specify at least one model")
return
print("Started!")
start_time = time.time()
streams = []
total_duration = 0
for wave_filename in args.sound_files:
assert_file_exists(wave_filename)
samples, sample_rate = read_wave(wave_filename)
duration = len(samples) / sample_rate
total_duration += duration
s = recognizer.create_stream()
s.accept_waveform(sample_rate, samples)
streams.append(s)
recognizer.decode_streams(streams)
results = [s.result.text for s in streams]
end_time = time.time()
print("Done!")
for wave_filename, result in zip(args.sound_files, results):
print(f"{wave_filename}\n{result}")
print("-" * 10)
elapsed_seconds = end_time - start_time
rtf = elapsed_seconds / total_duration
print(f"num_threads: {args.num_threads}")
print(f"decoding_method: {args.decoding_method}")
print(f"Wave duration: {total_duration:.3f} s")
print(f"Elapsed time: {elapsed_seconds:.3f} s")
print(
f"Real time factor (RTF): {elapsed_seconds:.3f}/{total_duration:.3f} = {rtf:.3f}"
)
if __name__ == "__main__":
main()