def decode_one(self, logits, padding):
from kaldi.matrix import Matrix
decoder = self.dec_cls(self.fst, self.decoder_options)
asr = self.rec_cls(decoder,
self.symbol_table,
acoustic_scale=self.acoustic_scale)
if padding is not None:
logits = logits[~padding]
mat = Matrix(logits.numpy())
out = asr.decode(mat)
if self.nbest > 1:
from kaldi.fstext import shortestpath
from kaldi.fstext.utils import (
convert_compact_lattice_to_lattice,
convert_lattice_to_std,
convert_nbest_to_list,
get_linear_symbol_sequence,
)
lat = out["lattice"]
sp = shortestpath(lat, nshortest=self.nbest)
sp = convert_compact_lattice_to_lattice(sp)
sp = convert_lattice_to_std(sp)
seq = convert_nbest_to_list(sp)
results = []
for s in seq:
_, o, w = get_linear_symbol_sequence(s)
words = list(self.output_symbols[z] for z in o)
results.append({
"tokens": words,
"words": words,
"score": w.value,
"emissions": logits,
})
return results
else:
words = out["text"].split()
return [{
"tokens": words,
"words": words,
"score": out["likelihood"],
"emissions": logits,
}]
def asr(filenameS_hash, filenameS, asr_beamsize=13, asr_max_active=8000):
models_dir = "models/"
# Read yaml File
config_file = "models/kaldi_tuda_de_nnet3_chain2.yaml"
with open(config_file, 'r') as stream:
model_yaml = yaml.safe_load(stream)
decoder_yaml_opts = model_yaml['decoder']
scp_filename = "tmp/%s.scp" % filenameS_hash
wav_filename = "tmp/%s.wav" % filenameS_hash
spk2utt_filename = "tmp/%s_spk2utt" % filenameS_hash
# write scp file
with open(scp_filename, 'w') as scp_file:
scp_file.write("%s tmp/%s.wav\n" % (filenameS_hash, filenameS_hash))
# write scp file
with open(spk2utt_filename, 'w') as scp_file:
scp_file.write("%s %s\n" % (filenameS_hash, filenameS_hash))
# use ffmpeg to convert the input media file (any format!) to 16 kHz wav mono
(
ffmpeg
.input(filename)
.output("tmp/%s.wav" % filenameS_hash, acodec='pcm_s16le', ac=1, ar='16k')
.overwrite_output()
.run()
)
# Construct recognizer
decoder_opts = LatticeFasterDecoderOptions()
decoder_opts.beam = asr_beamsize
decoder_opts.max_active = asr_max_active
decodable_opts = NnetSimpleComputationOptions()
decodable_opts.acoustic_scale = 1.0
decodable_opts.frame_subsampling_factor = 3
decodable_opts.frames_per_chunk = 150
asr = NnetLatticeFasterRecognizer.from_files(
models_dir + decoder_yaml_opts["model"],
models_dir + decoder_yaml_opts["fst"],
models_dir + decoder_yaml_opts["word-syms"],
decoder_opts=decoder_opts, decodable_opts=decodable_opts)
# Construct symbol table
symbols = SymbolTable.read_text(models_dir + decoder_yaml_opts["word-syms"])
phi_label = symbols.find_index("#0")
# Define feature pipelines as Kaldi rspecifiers
feats_rspec = ("ark:compute-mfcc-feats --config=%s scp:" + scp_filename + " ark:- |") % \
(models_dir + decoder_yaml_opts["mfcc-config"])
ivectors_rspec = (
("ark:compute-mfcc-feats --config=%s scp:" + scp_filename + " ark:-"
+ " | ivector-extract-online2 --config=%s ark:" + spk2utt_filename + " ark:- ark:- |") %
((models_dir + decoder_yaml_opts["mfcc-config"]),
(models_dir + decoder_yaml_opts["ivector-extraction-config"]))
)
did_decode = False
# Decode wav files
with SequentialMatrixReader(feats_rspec) as f, \
SequentialMatrixReader(ivectors_rspec) as i:
for (fkey, feats), (ikey, ivectors) in zip(f, i):
did_decode = True
assert (fkey == ikey)
out = asr.decode((feats, ivectors))
best_path = functions.compact_lattice_shortest_path(out["lattice"])
words, _, _ = get_linear_symbol_sequence(shortestpath(best_path))
timing = functions.compact_lattice_to_word_alignment(best_path)
assert(did_decode)
# Maps words to the numbers
words = indices_to_symbols(symbols, timing[0])
# Creates the datastructure (Word, begin(Frames), end(Frames))
vtt = list(map(list, zip(words, timing[1], timing[2])))
# Cleanup tmp files
print('removing tmp file:', scp_filename)
os.remove(scp_filename)
print('removing tmp file:', wav_filename)
os.remove(wav_filename)
print('removing tmp file:', spk2utt_filename)
os.remove(spk2utt_filename)
return vtt, words
rnnlm_opts.eos_index = symbols.find_index("</s>")
rnnlm_opts.brk_index = symbols.find_index("<brk>")
compose_opts = ComposeLatticePrunedOptions()
compose_opts.lattice_compose_beam = 4
rescorer = LatticeRnnlmPrunedRescorer.from_files(
"lm/G.carpa",
"rnnlm-get-word-embedding lm/word_feats.txt lm/feat_embedding.final.mat -|",
"lm/final.raw",
acoustic_scale=1.0,
max_ngram_order=4,
use_const_arpa=True,
opts=rnnlm_opts,
compose_opts=compose_opts)
# Define feature pipelines as Kaldi rspecifiers
feats_rspec = "ark:compute-mfcc-feats --config=mfcc.conf scp:wav.scp ark:- |"
ivectors_rspec = (
"ark:compute-mfcc-feats --config=mfcc.conf scp:wav.scp ark:-"
" | ivector-extract-online2 --config=ivector.conf ark:spk2utt ark:- ark:- |"
)
# Decode wav files
with SequentialMatrixReader(feats_rspec) as f, \
SequentialMatrixReader(ivectors_rspec) as i:
for (fkey, feats), (ikey, ivectors) in zip(f, i):
assert (fkey == ikey)
out = asr.decode((feats, ivectors))
rescored_lat = rescorer.rescore(out["lattice"])
words, _, _ = get_linear_symbol_sequence(shortestpath(rescored_lat))
print(fkey, " ".join(indices_to_symbols(symbols, words)), flush=True)