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egs/vystadial_cz/online_demo/pykaldi-online-latgen-recogniser.py 3.75 KB
8dcb6dfcb   Yannick Estève   first commit
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  #!/usr/bin/env python
  # Copyright (c) 2013, Ondrej Platek, Ufal MFF UK <oplatek@ufal.mff.cuni.cz>
  #
  # 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
  #
  # THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  # WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  # MERCHANTABLITY OR NON-INFRINGEMENT.
  # See the Apache 2 License for the specific language governing permissions and
  # limitations under the License. #
  from __future__ import unicode_literals
  from __future__ import division
  from __future__ import print_function
  
  from kaldi.utils import load_wav, wst2dict, lattice_to_nbest
  from kaldi.decoders import PyOnlineLatgenRecogniser
  import sys
  import fst
  import time
  
  # DEBUG = True
  DEBUG = False
  
  
  def write_decoded(f, wav_name, word_ids, wst):
      assert(len(word_ids) > 0)
      best_weight, best_path = word_ids[0]
      if wst is not None:
          decoded = [wst[w] for w in best_path]
      else:
          decoded = [str(w) for w in best_path]
      line = u' '.join([wav_name] + decoded + ['
  '])
      if DEBUG:
          print('%s best path %s' % (wav_name, decoded.encode('UTF-8')))
          for i, s in enumerate(word_ids):
              if i > 0:
                  break
              print('best path %d: %s' % (i, str(s)))
      f.write(line.encode('UTF-8'))
  
  
  # @profile
  def decode(d, pcm):
      frame_len = (2 * audio_batch_size)  # 16-bit audio so 1 sample = 2 chars
      i, decoded_frames, max_end = 0, 0, len(pcm)
      start = time.time()
      while i * frame_len < len(pcm):
          i, begin, end = i + 1, i * frame_len, min(max_end, (i + 1) * frame_len)
          audio_chunk = pcm[begin:end]
          d.frame_in(audio_chunk)
          dec_t = d.decode(max_frames=10)
          while dec_t > 0:
              decoded_frames += dec_t
              dec_t = d.decode(max_frames=10)
      print("forward decode: %s secs" % str(time.time() - start))
      start = time.time()
      d.prune_final()
      lik, lat = d.get_lattice()
      print("backward decode: %s secs" % str(time.time() - start))
      d.reset(keep_buffer_data=False)
      return (lat, lik, decoded_frames)
  
  
  def decode_wrap(argv, audio_batch_size, wav_paths,
          file_output, wst_path=None):
      wst = wst2dict(wst_path)
      d = PyOnlineLatgenRecogniser()
      d.setup(argv)
      for wav_name, wav_path in wav_paths:
          sw, sr = 2, 16000  # 16-bit audio so 1 sample_width = 2 chars
          pcm = load_wav(wav_path, def_sample_width=sw, def_sample_rate=sr)
          print('%s has %f sec' % (wav_name, (float(len(pcm)) / sw) / sr))
          lat, lik, decoded_frames = decode(d, pcm)
          lat.isyms = lat.osyms = fst.read_symbols_text(wst_path)
          if DEBUG:
              with open('pykaldi_%s.svg' % wav_name, 'w') as f:
                  f.write(lat._repr_svg_())
              lat.write('%s_pykaldi.fst' % wav_name)
  
          print("Log-likelihood per frame for utterance %s is %f over %d frames" % (
              wav_name, int(lik / decoded_frames), decoded_frames))
          word_ids = lattice_to_nbest(lat, n=10)
          write_decoded(file_output, wav_name, word_ids, wst)
  
  
  if __name__ == '__main__':
      audio_scp, audio_batch_size = sys.argv[1], int(sys.argv[2])
      dec_hypo, wst_path = sys.argv[3], sys.argv[4]
      argv = sys.argv[5:]
      print('Python args: %s' % str(sys.argv), file=sys.stderr)
  
      # open audio_scp, decode and write to dec_hypo file
      with open(audio_scp, 'rb') as r:
          with open(dec_hypo, 'wb') as w:
              lines = r.readlines()
              scp = [tuple(line.strip().split(' ', 1)) for line in lines]
              decode_wrap(argv, audio_batch_size, scp, w, wst_path)