deploy: 13f55d073513b3beaefdf0b7e16237b35199ca04

2025-08-09 01:52:41 +00:00 · 2024-06-12 16:02:46 +00:00 · 2024-06-12 16:02:46 +00:00 · 7b03f27183
commit 7b03f27183
parent 2660477d0d
90 changed files with 2160 additions and 20 deletions
--- a/_sources/docker/intro.rst.txt
+++ b/_sources/docker/intro.rst.txt
@ -34,6 +34,8 @@ which will give you something like below:

 .. code-block:: bash

+  "torch2.3.1-cuda12.1"
+  "torch2.3.1-cuda11.8"
  "torch2.2.2-cuda12.1"
  "torch2.2.2-cuda11.8"
  "torch2.2.1-cuda12.1"
--- a/_sources/fst-based-forced-alignment/diff.rst.txt
+++ b/_sources/fst-based-forced-alignment/diff.rst.txt
@ -0,0 +1,41 @@
+Two approaches
+==============
+
+Two approaches for FST-based forced alignment will be described:
+
+  - `Kaldi`_-based
+  - `k2`_-based
+
+Note that the `Kaldi`_-based approach does not depend on `Kaldi`_ at all.
+That is, you don't need to install `Kaldi`_ in order to use it. Instead,
+we use `kaldi-decoder`_, which has ported the C++ decoding code from `Kaldi`_
+without depending on it.
+
+Differences between the two approaches
+--------------------------------------
+
+The following table compares the differences between the two approaches.
+
+.. list-table::
+
+ * - Features
+   - `Kaldi`_-based
+   - `k2`_-based
+ * - Support CUDA
+   - No
+   - Yes
+ * - Support CPU
+   - Yes
+   - Yes
+ * - Support batch processing
+   - No
+   - Yes on CUDA; No on CPU
+ * - Support streaming models
+   - Yes
+   - No
+ * - Support C++ APIs
+   - Yes
+   - Yes
+ * - Support Python APIs
+   - Yes
+   - Yes
--- a/_sources/fst-based-forced-alignment/index.rst.txt
+++ b/_sources/fst-based-forced-alignment/index.rst.txt
@ -0,0 +1,18 @@
+FST-based forced alignment
+==========================
+
+This section describes how to perform **FST-based** ``forced alignment`` with models
+trained by `CTC`_ loss.
+
+We use `CTC FORCED ALIGNMENT API TUTORIAL <https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html>`_
+from `torchaudio`_ as a reference in this section.
+
+Different from `torchaudio`_, we use an ``FST``-based approach.
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+   diff
+   kaldi-based
+   k2-based
--- a/_sources/fst-based-forced-alignment/k2-based.rst.txt
+++ b/_sources/fst-based-forced-alignment/k2-based.rst.txt
@ -0,0 +1,4 @@
+k2-based forced alignment
+=========================
+
+TODO(fangjun)
--- a/_sources/fst-based-forced-alignment/kaldi-based.rst.txt
+++ b/_sources/fst-based-forced-alignment/kaldi-based.rst.txt
@ -0,0 +1,712 @@
+Kaldi-based forced alignment
+============================
+
+This section describes in detail how to use `kaldi-decoder`_
+for **FST-based** ``forced alignment`` with models trained by `CTC`_ loss.
+
+.. hint::
+
+  We have a colab notebook walking you through this section step by step.
+
+  |kaldi-based forced alignment colab notebook|
+
+  .. |kaldi-based forced alignment colab notebook| image:: https://colab.research.google.com/assets/colab-badge.svg
+     :target: https://github.com/k2-fsa/colab/blob/master/icefall/ctc_forced_alignment_fst_based_kaldi.ipynb
+
+Prepare the environment
+-----------------------
+
+Before you continue, make sure you have setup `icefall`_ by following :ref:`install icefall`.
+
+.. hint::
+
+   You don't need to install `Kaldi`_. We will ``NOT`` use `Kaldi`_ below.
+
+Get the test data
+-----------------
+
+We use the test wave
+from `CTC FORCED ALIGNMENT API TUTORIAL <https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html>`_
+
+.. code-block:: python3
+
+  import torchaudio
+
+  # Download test wave
+  speech_file = torchaudio.utils.download_asset("tutorial-assets/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav")
+  print(speech_file)
+  waveform, sr = torchaudio.load(speech_file)
+  transcript = "i had that curiosity beside me at this moment".split()
+  print(waveform.shape, sr)
+
+  assert waveform.ndim == 2
+  assert waveform.shape[0] == 1
+  assert sr == 16000
+
+The test wave is downloaded to::
+
+  $HOME/.cache/torch/hub/torchaudio/tutorial-assets/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav
+
+.. raw:: html
+
+  <table>
+    <tr>
+      <th>Wave filename</th>
+      <th>Content</th>
+      <th>Text</th>
+    </tr>
+    <tr>
+      <td>Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav</td>
+      <td>
+       <audio title="Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+      <td>
+        i had that curiosity beside me at this moment
+      </td>
+    </tr>
+  </table>
+
+We use the test model
+from `CTC FORCED ALIGNMENT API TUTORIAL <https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html>`_
+
+.. code-block:: python3
+
+  import torch
+
+  bundle = torchaudio.pipelines.MMS_FA
+
+  device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+  model = bundle.get_model(with_star=False).to(device)
+
+The model is downloaded to::
+
+  $HOME/.cache/torch/hub/checkpoints/model.pt
+
+Compute log_probs
+-----------------
+
+.. code-block:: bash
+
+  with torch.inference_mode():
+      emission, _ = model(waveform.to(device))
+      print(emission.shape)
+
+It should print::
+
+  torch.Size([1, 169, 28])
+
+Create token2id and id2token
+----------------------------
+
+.. code-block:: python3
+
+    token2id = bundle.get_dict(star=None)
+    id2token = {i:t for t, i in token2id.items()}
+    token2id["<eps>"] = 0
+    del token2id["-"]
+
+Create word2id and id2word
+--------------------------
+
+.. code-block:: python3
+
+  words = list(set(transcript))
+  word2id = dict()
+  word2id['eps'] = 0
+  for i, w in enumerate(words):
+    word2id[w] = i + 1
+
+  id2word = {i:w for w, i in word2id.items()}
+
+Note that we only use words from the transcript of the test wave.
+
+Generate lexicon-related files
+------------------------------
+
+We use the code below to generate the following 4 files:
+
+  - ``lexicon.txt``
+  - ``tokens.txt``
+  - ``words.txt``
+  - ``lexicon_disambig.txt``
+
+.. caution::
+
+   ``words.txt`` contains only words from the transcript of the test wave.
+
+.. code-block:: python3
+
+  from prepare_lang import add_disambig_symbols
+
+  lexicon = [(w, list(w)) for w in word2id if w != "eps"]
+  lexicon_disambig, max_disambig_id = add_disambig_symbols(lexicon)
+
+  with open('lexicon.txt', 'w', encoding='utf-8') as f:
+    for w, tokens in lexicon:
+      f.write(f"{w} {' '.join(tokens)}\n")
+
+  with open('lexicon_disambig.txt', 'w', encoding='utf-8') as f:
+    for w, tokens in lexicon_disambig:
+      f.write(f"{w} {' '.join(tokens)}\n")
+
+  with open('tokens.txt', 'w', encoding='utf-8') as f:
+    for t, i in token2id.items():
+      if t == '-':
+        t = "<eps>"
+      f.write(f"{t} {i}\n")
+
+    for k in range(max_disambig_id + 2):
+      f.write(f"#{k} {len(token2id) + k}\n")
+
+  with open('words.txt', 'w', encoding='utf-8') as f:
+    for w, i in word2id.items():
+      f.write(f"{w} {i}\n")
+    f.write(f'#0 {len(word2id)}\n')
+
+
+To give you an idea about what the generated files look like::
+
+  head -n 50 lexicon.txt lexicon_disambig.txt tokens.txt words.txt
+
+prints::
+
+  ==> lexicon.txt <==
+  moment m o m e n t
+  beside b e s i d e
+  i i
+  this t h i s
+  curiosity c u r i o s i t y
+  had h a d
+  that t h a t
+  at a t
+  me m e
+
+  ==> lexicon_disambig.txt <==
+  moment m o m e n t
+  beside b e s i d e
+  i i
+  this t h i s
+  curiosity c u r i o s i t y
+  had h a d
+  that t h a t
+  at a t
+  me m e
+
+  ==> tokens.txt <==
+  a 1
+  i 2
+  e 3
+  n 4
+  o 5
+  u 6
+  t 7
+  s 8
+  r 9
+  m 10
+  k 11
+  l 12
+  d 13
+  g 14
+  h 15
+  y 16
+  b 17
+  p 18
+  w 19
+  c 20
+  v 21
+  j 22
+  z 23
+  f 24
+  ' 25
+  q 26
+  x 27
+  <eps> 0
+  #0 28
+  #1 29
+
+  ==> words.txt <==
+  eps 0
+  moment 1
+  beside 2
+  i 3
+  this 4
+  curiosity 5
+  had 6
+  that 7
+  at 8
+  me 9
+  #0 10
+
+.. note::
+
+   This test model uses characters as modeling unit. If you use other types of
+   modeling unit, the same code can be used without any change.
+
+Convert transcript to an FST graph
+----------------------------------
+
+.. code-block:: bash
+
+   egs/librispeech/ASR/local/prepare_lang_fst.py --lang-dir ./
+
+The above command should generate two files ``H.fst`` and ``HL.fst``. We will
+use ``HL.fst`` below::
+
+  -rw-r--r-- 1 root root  13K Jun 12 08:28 H.fst
+  -rw-r--r-- 1 root root 3.7K Jun 12 08:28 HL.fst
+
+Force aligner
+-------------
+
+Now, everything is ready. We can use the following code to get forced alignments.
+
+.. code-block:: python3
+
+  from kaldi_decoder import DecodableCtc, FasterDecoder, FasterDecoderOptions
+  import kaldifst
+
+  def force_align():
+      HL = kaldifst.StdVectorFst.read("./HL.fst")
+      decodable = DecodableCtc(emission[0].contiguous().cpu().numpy())
+      decoder_opts = FasterDecoderOptions(max_active=3000)
+      decoder = FasterDecoder(HL, decoder_opts)
+      decoder.decode(decodable)
+      if not decoder.reached_final():
+          print(f"failed to decode xxx")
+          return None
+      ok, best_path = decoder.get_best_path()
+
+      (
+          ok,
+          isymbols_out,
+          osymbols_out,
+          total_weight,
+      ) = kaldifst.get_linear_symbol_sequence(best_path)
+      if not ok:
+          print(f"failed to get linear symbol sequence for xxx")
+          return None
+
+      # We need to use i-1 here since we have incremented tokens during
+      # HL construction
+      alignment = [i-1 for i in isymbols_out]
+      return alignment
+
+  alignment = force_align()
+
+  for i, a in enumerate(alignment):
+    print(i, id2token[a])
+
+The output should be identical to
+`<https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html#frame-level-alignments>`_.
+
+For ease of reference, we list the output below::
+
+  0 -
+  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 i
+  33 -
+  34 -
+  35 h
+  36 h
+  37 a
+  38 -
+  39 -
+  40 -
+  41 d
+  42 -
+  43 -
+  44 t
+  45 h
+  46 -
+  47 a
+  48 -
+  49 -
+  50 t
+  51 -
+  52 -
+  53 -
+  54 c
+  55 -
+  56 -
+  57 -
+  58 u
+  59 u
+  60 -
+  61 -
+  62 -
+  63 r
+  64 -
+  65 i
+  66 -
+  67 -
+  68 -
+  69 -
+  70 -
+  71 -
+  72 o
+  73 -
+  74 -
+  75 -
+  76 -
+  77 -
+  78 -
+  79 s
+  80 -
+  81 -
+  82 -
+  83 i
+  84 -
+  85 t
+  86 -
+  87 -
+  88 y
+  89 -
+  90 -
+  91 -
+  92 -
+  93 b
+  94 -
+  95 e
+  96 -
+  97 -
+  98 -
+  99 -
+  100 -
+  101 s
+  102 -
+  103 -
+  104 -
+  105 -
+  106 -
+  107 -
+  108 -
+  109 -
+  110 i
+  111 -
+  112 -
+  113 d
+  114 e
+  115 -
+  116 m
+  117 -
+  118 -
+  119 e
+  120 -
+  121 -
+  122 -
+  123 -
+  124 a
+  125 -
+  126 -
+  127 t
+  128 -
+  129 t
+  130 h
+  131 -
+  132 i
+  133 -
+  134 -
+  135 -
+  136 s
+  137 -
+  138 -
+  139 -
+  140 -
+  141 m
+  142 -
+  143 -
+  144 o
+  145 -
+  146 -
+  147 -
+  148 m
+  149 -
+  150 -
+  151 e
+  152 -
+  153 n
+  154 -
+  155 t
+  156 -
+  157 -
+  158 -
+  159 -
+  160 -
+  161 -
+  162 -
+  163 -
+  164 -
+  165 -
+  166 -
+  167 -
+  168 -
+
+To merge tokens, we use::
+
+  from icefall.ctc import merge_tokens
+  token_spans = merge_tokens(alignment)
+  for span in token_spans:
+    print(id2token[span.token], span.start, span.end)
+
+The output is given below::
+
+  i 32 33
+  h 35 37
+  a 37 38
+  d 41 42
+  t 44 45
+  h 45 46
+  a 47 48
+  t 50 51
+  c 54 55
+  u 58 60
+  r 63 64
+  i 65 66
+  o 72 73
+  s 79 80
+  i 83 84
+  t 85 86
+  y 88 89
+  b 93 94
+  e 95 96
+  s 101 102
+  i 110 111
+  d 113 114
+  e 114 115
+  m 116 117
+  e 119 120
+  a 124 125
+  t 127 128
+  t 129 130
+  h 130 131
+  i 132 133
+  s 136 137
+  m 141 142
+  o 144 145
+  m 148 149
+  e 151 152
+  n 153 154
+  t 155 156
+
+All of the code below is copied and modified
+from `<https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html>`_.
+
+Segment each word using the computed alignments
+-----------------------------------------------
+
+.. code-block:: python3
+
+  def unflatten(list_, lengths):
+      assert len(list_) == sum(lengths)
+      i = 0
+      ret = []
+      for l in lengths:
+          ret.append(list_[i : i + l])
+          i += l
+      return ret
+
+
+  word_spans = unflatten(token_spans, [len(word) for word in transcript])
+  print(word_spans)
+
+The output is::
+
+  [[TokenSpan(token=2, start=32, end=33)],
+   [TokenSpan(token=15, start=35, end=37), TokenSpan(token=1, start=37, end=38), TokenSpan(token=13, start=41, end=42)],
+   [TokenSpan(token=7, start=44, end=45), TokenSpan(token=15, start=45, end=46), TokenSpan(token=1, start=47, end=48), TokenSpan(token=7, start=50, end=51)],
+   [TokenSpan(token=20, start=54, end=55), TokenSpan(token=6, start=58, end=60), TokenSpan(token=9, start=63, end=64), TokenSpan(token=2, start=65, end=66), TokenSpan(token=5, start=72, end=73), TokenSpan(token=8, start=79, end=80), TokenSpan(token=2, start=83, end=84), TokenSpan(token=7, start=85, end=86), TokenSpan(token=16, start=88, end=89)],
+   [TokenSpan(token=17, start=93, end=94), TokenSpan(token=3, start=95, end=96), TokenSpan(token=8, start=101, end=102), TokenSpan(token=2, start=110, end=111), TokenSpan(token=13, start=113, end=114), TokenSpan(token=3, start=114, end=115)],
+   [TokenSpan(token=10, start=116, end=117), TokenSpan(token=3, start=119, end=120)],
+   [TokenSpan(token=1, start=124, end=125), TokenSpan(token=7, start=127, end=128)],
+   [TokenSpan(token=7, start=129, end=130), TokenSpan(token=15, start=130, end=131), TokenSpan(token=2, start=132, end=133), TokenSpan(token=8, start=136, end=137)],
+   [TokenSpan(token=10, start=141, end=142), TokenSpan(token=5, start=144, end=145), TokenSpan(token=10, start=148, end=149), TokenSpan(token=3, start=151, end=152), TokenSpan(token=4, start=153, end=154), TokenSpan(token=7, start=155, end=156)]
+  ]
+
+
+.. code-block:: python3
+
+  def preview_word(waveform, spans, num_frames, transcript, sample_rate=bundle.sample_rate):
+      ratio = waveform.size(1) / num_frames
+      x0 = int(ratio * spans[0].start)
+      x1 = int(ratio * spans[-1].end)
+      print(f"{transcript} {x0 / sample_rate:.3f} - {x1 / sample_rate:.3f} sec")
+      segment = waveform[:, x0:x1]
+      return IPython.display.Audio(segment.numpy(), rate=sample_rate)
+  num_frames = emission.size(1)
+
+.. code-block:: python3
+
+   preview_word(waveform, word_spans[0], num_frames, transcript[0])
+   preview_word(waveform, word_spans[1], num_frames, transcript[1])
+   preview_word(waveform, word_spans[2], num_frames, transcript[2])
+   preview_word(waveform, word_spans[3], num_frames, transcript[3])
+   preview_word(waveform, word_spans[4], num_frames, transcript[4])
+   preview_word(waveform, word_spans[5], num_frames, transcript[5])
+   preview_word(waveform, word_spans[6], num_frames, transcript[6])
+   preview_word(waveform, word_spans[7], num_frames, transcript[7])
+   preview_word(waveform, word_spans[8], num_frames, transcript[8])
+
+The segmented wave of each word along with its time stamp is given below:
+
+.. raw:: html
+
+  <table>
+    <tr>
+      <th>Word</th>
+      <th>Time</th>
+      <th>Wave</th>
+    </tr>
+    <tr>
+      <td>i</td>
+      <td>0.644 - 0.664 sec</td>
+      <td>
+       <audio title="i.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/i.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>had</td>
+      <td>0.704 - 0.845 sec</td>
+      <td>
+       <audio title="had.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/had.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>that</td>
+      <td>0.885 - 1.026 sec</td>
+      <td>
+       <audio title="that.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/that.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>curiosity</td>
+      <td>1.086 - 1.790 sec</td>
+      <td>
+       <audio title="curiosity.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/curiosity.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>beside</td>
+      <td>1.871 - 2.314 sec</td>
+      <td>
+       <audio title="beside.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/beside.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>me</td>
+      <td>2.334 - 2.414 sec</td>
+      <td>
+       <audio title="me.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/me.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>at</td>
+      <td>2.495 - 2.575 sec</td>
+      <td>
+       <audio title="at.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/at.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>this</td>
+      <td>2.595 - 2.756 sec</td>
+      <td>
+       <audio title="this.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/this.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+    <tr>
+      <td>moment</td>
+      <td>2.837 - 3.138 sec</td>
+      <td>
+       <audio title="moment.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/moment.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+    </tr>
+  </table>
+
+We repost the whole wave below for ease of reference:
+
+.. raw:: html
+
+  <table>
+    <tr>
+      <th>Wave filename</th>
+      <th>Content</th>
+      <th>Text</th>
+    </tr>
+    <tr>
+      <td>Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav</td>
+      <td>
+       <audio title="Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" controls="controls">
+             <source src="/icefall/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" type="audio/wav">
+             Your browser does not support the <code>audio</code> element.
+       </audio>
+      </td>
+      <td>
+        i had that curiosity beside me at this moment
+      </td>
+    </tr>
+  </table>
+
+Summary
+-------
+
+Congratulations! You have succeeded in using the FST-based approach to
+compute alignment of a test wave.
--- a/_sources/index.rst.txt
+++ b/_sources/index.rst.txt
@ -25,7 +25,7 @@ speech recognition recipes using `k2 <https://github.com/k2-fsa/k2>`_.
   docker/index
   faqs
   model-export/index
-
+   fst-based-forced-alignment/index

 .. toctree::
   :maxdepth: 3
@ -40,5 +40,5 @@ speech recognition recipes using `k2 <https://github.com/k2-fsa/k2>`_.

 .. toctree::
   :maxdepth: 2
-   
+
   decoding-with-langugage-models/index
--- a/_sources/model-export/export-ncnn-conv-emformer.rst.txt
+++ b/_sources/model-export/export-ncnn-conv-emformer.rst.txt
@ -15,8 +15,8 @@ We will show you step by step how to export it to `ncnn`_ and run it with `sherp

 .. caution::

-  Please use a more recent version of PyTorch. For instance, ``torch 1.8``
-  may ``not`` work.
+  ``torch > 2.0`` may not work. If you get errors while building pnnx, please switch
+  to ``torch < 2.0``.

 1. Download the pre-trained model
 ---------------------------------
--- a/_sources/model-export/export-ncnn-lstm.rst.txt
+++ b/_sources/model-export/export-ncnn-lstm.rst.txt
@ -15,8 +15,8 @@ We will show you step by step how to export it to `ncnn`_ and run it with `sherp

 .. caution::

-  Please use a more recent version of PyTorch. For instance, ``torch 1.8``
-  may ``not`` work.
+  ``torch > 2.0`` may not work. If you get errors while building pnnx, please switch
+  to ``torch < 2.0``.

 1. Download the pre-trained model
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
--- a/_sources/model-export/export-ncnn-zipformer.rst.txt
+++ b/_sources/model-export/export-ncnn-zipformer.rst.txt
@ -15,8 +15,8 @@ We will show you step by step how to export it to `ncnn`_ and run it with `sherp

 .. caution::

-  Please use a more recent version of PyTorch. For instance, ``torch 1.8``
-  may ``not`` work.
+  ``torch > 2.0`` may not work. If you get errors while building pnnx, please switch
+  to ``torch < 2.0``.

 1. Download the pre-trained model
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
--- a/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav
+++ b/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav
--- a/_static/kaldi-align/at.wav
+++ b/_static/kaldi-align/at.wav
--- a/_static/kaldi-align/beside.wav
+++ b/_static/kaldi-align/beside.wav
--- a/_static/kaldi-align/curiosity.wav
+++ b/_static/kaldi-align/curiosity.wav
--- a/_static/kaldi-align/had.wav
+++ b/_static/kaldi-align/had.wav
--- a/_static/kaldi-align/i.wav
+++ b/_static/kaldi-align/i.wav
--- a/_static/kaldi-align/me.wav
+++ b/_static/kaldi-align/me.wav
--- a/_static/kaldi-align/moment.wav
+++ b/_static/kaldi-align/moment.wav
--- a/_static/kaldi-align/that.wav
+++ b/_static/kaldi-align/that.wav
--- a/_static/kaldi-align/this.wav
+++ b/_static/kaldi-align/this.wav
--- a/contributing/code-style.html
+++ b/contributing/code-style.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/contributing/doc.html
+++ b/contributing/doc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/contributing/how-to-create-a-recipe.html
+++ b/contributing/how-to-create-a-recipe.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/contributing/index.html
+++ b/contributing/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/decoding-with-langugage-models/LODR.html
+++ b/decoding-with-langugage-models/LODR.html
@ -52,6 +52,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/decoding-with-langugage-models/index.html
+++ b/decoding-with-langugage-models/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/decoding-with-langugage-models/rescoring.html
+++ b/decoding-with-langugage-models/rescoring.html
@ -50,6 +50,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/decoding-with-langugage-models/shallow-fusion.html
+++ b/decoding-with-langugage-models/shallow-fusion.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/docker/index.html
+++ b/docker/index.html
@ -60,6 +60,7 @@
 </li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/docker/intro.html
+++ b/docker/intro.html
@ -70,6 +70,7 @@
 </li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
@ -136,7 +137,9 @@ docker images:</p>
 </pre></div>
 </div>
 <p>which will give you something like below:</p>
-<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span><span class="s2">&quot;torch2.2.2-cuda12.1&quot;</span>
+<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span><span class="s2">&quot;torch2.3.1-cuda12.1&quot;</span>
+<span class="s2">&quot;torch2.3.1-cuda11.8&quot;</span>
+<span class="s2">&quot;torch2.2.2-cuda12.1&quot;</span>
 <span class="s2">&quot;torch2.2.2-cuda11.8&quot;</span>
 <span class="s2">&quot;torch2.2.1-cuda12.1&quot;</span>
 <span class="s2">&quot;torch2.2.1-cuda11.8&quot;</span>
--- a/faqs.html
+++ b/faqs.html
@ -56,6 +56,7 @@
 </ul>
 </li>
 <li class="toctree-l1"><a class="reference internal" href="model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="recipes/index.html">Recipes</a></li>
--- a/for-dummies/data-preparation.html
+++ b/for-dummies/data-preparation.html
@ -66,6 +66,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/for-dummies/decoding.html
+++ b/for-dummies/decoding.html
@ -61,6 +61,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/for-dummies/environment-setup.html
+++ b/for-dummies/environment-setup.html
@ -64,6 +64,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/for-dummies/index.html
+++ b/for-dummies/index.html
@ -58,6 +58,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/for-dummies/model-export.html
+++ b/for-dummies/model-export.html
@ -64,6 +64,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/for-dummies/training.html
+++ b/for-dummies/training.html
@ -61,6 +61,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/fst-based-forced-alignment/diff.html
+++ b/fst-based-forced-alignment/diff.html
@ -0,0 +1,182 @@
+<!DOCTYPE html>
+<html class="writer-html5" lang="en">
+<head>
+  <meta charset="utf-8" /><meta name="viewport" content="width=device-width, initial-scale=1" />
+
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>Two approaches &mdash; icefall 0.1 documentation</title>
+      <link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=fa44fd50" />
+      <link rel="stylesheet" type="text/css" href="../_static/css/theme.css?v=19f00094" />
+
+  
+  <!--[if lt IE 9]>
+    <script src="../_static/js/html5shiv.min.js"></script>
+  <![endif]-->
+  
+        <script src="../_static/jquery.js?v=5d32c60e"></script>
+        <script src="../_static/_sphinx_javascript_frameworks_compat.js?v=2cd50e6c"></script>
+        <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js?v=e031e9a9"></script>
+        <script src="../_static/doctools.js?v=888ff710"></script>
+        <script src="../_static/sphinx_highlight.js?v=4825356b"></script>
+    <script src="../_static/js/theme.js"></script>
+    <link rel="index" title="Index" href="../genindex.html" />
+    <link rel="search" title="Search" href="../search.html" />
+    <link rel="next" title="Kaldi-based forced alignment" href="kaldi-based.html" />
+    <link rel="prev" title="FST-based forced alignment" href="index.html" /> 
+</head>
+
+<body class="wy-body-for-nav"> 
+  <div class="wy-grid-for-nav">
+    <nav data-toggle="wy-nav-shift" class="wy-nav-side">
+      <div class="wy-side-scroll">
+        <div class="wy-side-nav-search" >
+
+          
+          
+          <a href="../index.html" class="icon icon-home">
+            icefall
+          </a>
+<div role="search">
+  <form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
+    <input type="text" name="q" placeholder="Search docs" aria-label="Search docs" />
+    <input type="hidden" name="check_keywords" value="yes" />
+    <input type="hidden" name="area" value="default" />
+  </form>
+</div>
+        </div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu">
+              <p class="caption" role="heading"><span class="caption-text">Contents:</span></p>
+<ul class="current">
+<li class="toctree-l1"><a class="reference internal" href="../for-dummies/index.html">Icefall for dummies tutorial</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1 current"><a class="reference internal" href="index.html">FST-based forced alignment</a><ul class="current">
+<li class="toctree-l2 current"><a class="current reference internal" href="#">Two approaches</a><ul>
+<li class="toctree-l3"><a class="reference internal" href="#differences-between-the-two-approaches">Differences between the two approaches</a></li>
+</ul>
+</li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html">Kaldi-based forced alignment</a></li>
+<li class="toctree-l2"><a class="reference internal" href="k2-based.html">k2-based forced alignment</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../huggingface/index.html">Huggingface</a></li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../decoding-with-langugage-models/index.html">Decoding with language models</a></li>
+</ul>
+
+        </div>
+      </div>
+    </nav>
+
+    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"><nav class="wy-nav-top" aria-label="Mobile navigation menu" >
+          <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
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+      <li><a href="../index.html" class="icon icon-home" aria-label="Home"></a></li>
+          <li class="breadcrumb-item"><a href="index.html">FST-based forced alignment</a></li>
+      <li class="breadcrumb-item active">Two approaches</li>
+      <li class="wy-breadcrumbs-aside">
+              <a href="https://github.com/k2-fsa/icefall/blob/master/docs/source/fst-based-forced-alignment/diff.rst" class="fa fa-github"> Edit on GitHub</a>
+      </li>
+  </ul>
+  <hr/>
+</div>
+          <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
+           <div itemprop="articleBody">
+             
+  <section id="two-approaches">
+<h1>Two approaches<a class="headerlink" href="#two-approaches" title="Permalink to this heading"></a></h1>
+<p>Two approaches for FST-based forced alignment will be described:</p>
+<blockquote>
+<div><ul class="simple">
+<li><p><a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a>-based</p></li>
+<li><p><a class="reference external" href="https://github.com/k2-fsa/k2">k2</a>-based</p></li>
+</ul>
+</div></blockquote>
+<p>Note that the <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a>-based approach does not depend on <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a> at all.
+That is, you don’t need to install <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a> in order to use it. Instead,
+we use <a class="reference external" href="https://github.com/k2-fsa/kaldi-decoder">kaldi-decoder</a>, which has ported the C++ decoding code from <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a>
+without depending on it.</p>
+<section id="differences-between-the-two-approaches">
+<h2>Differences between the two approaches<a class="headerlink" href="#differences-between-the-two-approaches" title="Permalink to this heading"></a></h2>
+<p>The following table compares the differences between the two approaches.</p>
+<table class="docutils align-default">
+<tbody>
+<tr class="row-odd"><td><p>Features</p></td>
+<td><p><a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a>-based</p></td>
+<td><p><a class="reference external" href="https://github.com/k2-fsa/k2">k2</a>-based</p></td>
+</tr>
+<tr class="row-even"><td><p>Support CUDA</p></td>
+<td><p>No</p></td>
+<td><p>Yes</p></td>
+</tr>
+<tr class="row-odd"><td><p>Support CPU</p></td>
+<td><p>Yes</p></td>
+<td><p>Yes</p></td>
+</tr>
+<tr class="row-even"><td><p>Support batch processing</p></td>
+<td><p>No</p></td>
+<td><p>Yes on CUDA; No on CPU</p></td>
+</tr>
+<tr class="row-odd"><td><p>Support streaming models</p></td>
+<td><p>Yes</p></td>
+<td><p>No</p></td>
+</tr>
+<tr class="row-even"><td><p>Support C++ APIs</p></td>
+<td><p>Yes</p></td>
+<td><p>Yes</p></td>
+</tr>
+<tr class="row-odd"><td><p>Support Python APIs</p></td>
+<td><p>Yes</p></td>
+<td><p>Yes</p></td>
+</tr>
+</tbody>
+</table>
+</section>
+</section>
+
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+             
+  <section id="fst-based-forced-alignment">
+<h1>FST-based forced alignment<a class="headerlink" href="#fst-based-forced-alignment" title="Permalink to this heading"></a></h1>
+<p>This section describes how to perform <strong>FST-based</strong> <code class="docutils literal notranslate"><span class="pre">forced</span> <span class="pre">alignment</span></code> with models
+trained by <a class="reference external" href="https://www.cs.toronto.edu/~graves/icml_2006.pdf">CTC</a> loss.</p>
+<p>We use <a class="reference external" href="https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html">CTC FORCED ALIGNMENT API TUTORIAL</a>
+from <a class="reference external" href="https://github.com/pytorch/audio">torchaudio</a> as a reference in this section.</p>
+<p>Different from <a class="reference external" href="https://github.com/pytorch/audio">torchaudio</a>, we use an <code class="docutils literal notranslate"><span class="pre">FST</span></code>-based approach.</p>
+<div class="toctree-wrapper compound">
+<p class="caption" role="heading"><span class="caption-text">Contents:</span></p>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="diff.html">Two approaches</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="diff.html#differences-between-the-two-approaches">Differences between the two approaches</a></li>
+</ul>
+</li>
+<li class="toctree-l1"><a class="reference internal" href="kaldi-based.html">Kaldi-based forced alignment</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#prepare-the-environment">Prepare the environment</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#get-the-test-data">Get the test data</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#compute-log-probs">Compute log_probs</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#create-token2id-and-id2token">Create token2id and id2token</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#create-word2id-and-id2word">Create word2id and id2word</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#generate-lexicon-related-files">Generate lexicon-related files</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#convert-transcript-to-an-fst-graph">Convert transcript to an FST graph</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#force-aligner">Force aligner</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#segment-each-word-using-the-computed-alignments">Segment each word using the computed alignments</a></li>
+<li class="toctree-l2"><a class="reference internal" href="kaldi-based.html#summary">Summary</a></li>
+</ul>
+</li>
+<li class="toctree-l1"><a class="reference internal" href="k2-based.html">k2-based forced alignment</a></li>
+</ul>
+</div>
+</section>
+
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+             
+  <section id="k2-based-forced-alignment">
+<h1>k2-based forced alignment<a class="headerlink" href="#k2-based-forced-alignment" title="Permalink to this heading"></a></h1>
+<p>TODO(fangjun)</p>
+</section>
+
+
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+<li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1 current"><a class="reference internal" href="index.html">FST-based forced alignment</a><ul class="current">
+<li class="toctree-l2"><a class="reference internal" href="diff.html">Two approaches</a></li>
+<li class="toctree-l2 current"><a class="current reference internal" href="#">Kaldi-based forced alignment</a><ul>
+<li class="toctree-l3"><a class="reference internal" href="#prepare-the-environment">Prepare the environment</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#get-the-test-data">Get the test data</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#compute-log-probs">Compute log_probs</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#create-token2id-and-id2token">Create token2id and id2token</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#create-word2id-and-id2word">Create word2id and id2word</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#generate-lexicon-related-files">Generate lexicon-related files</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#convert-transcript-to-an-fst-graph">Convert transcript to an FST graph</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#force-aligner">Force aligner</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#segment-each-word-using-the-computed-alignments">Segment each word using the computed alignments</a></li>
+<li class="toctree-l3"><a class="reference internal" href="#summary">Summary</a></li>
+</ul>
+</li>
+<li class="toctree-l2"><a class="reference internal" href="k2-based.html">k2-based forced alignment</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../huggingface/index.html">Huggingface</a></li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../decoding-with-langugage-models/index.html">Decoding with language models</a></li>
+</ul>
+
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+             
+  <section id="kaldi-based-forced-alignment">
+<h1>Kaldi-based forced alignment<a class="headerlink" href="#kaldi-based-forced-alignment" title="Permalink to this heading"></a></h1>
+<p>This section describes in detail how to use <a class="reference external" href="https://github.com/k2-fsa/kaldi-decoder">kaldi-decoder</a>
+for <strong>FST-based</strong> <code class="docutils literal notranslate"><span class="pre">forced</span> <span class="pre">alignment</span></code> with models trained by <a class="reference external" href="https://www.cs.toronto.edu/~graves/icml_2006.pdf">CTC</a> loss.</p>
+<div class="admonition hint">
+<p class="admonition-title">Hint</p>
+<p>We have a colab notebook walking you through this section step by step.</p>
+<p><a class="reference external" href="https://github.com/k2-fsa/colab/blob/master/icefall/ctc_forced_alignment_fst_based_kaldi.ipynb"><img alt="kaldi-based forced alignment colab notebook" src="https://colab.research.google.com/assets/colab-badge.svg" /></a></p>
+</div>
+<section id="prepare-the-environment">
+<h2>Prepare the environment<a class="headerlink" href="#prepare-the-environment" title="Permalink to this heading"></a></h2>
+<p>Before you continue, make sure you have setup <a class="reference external" href="https://github.com/k2-fsa/icefall">icefall</a> by following <a class="reference internal" href="../installation/index.html#install-icefall"><span class="std std-ref">Installation</span></a>.</p>
+<div class="admonition hint">
+<p class="admonition-title">Hint</p>
+<p>You don’t need to install <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a>. We will <code class="docutils literal notranslate"><span class="pre">NOT</span></code> use <a class="reference external" href="https://github.com/kaldi-asr/kaldi">Kaldi</a> below.</p>
+</div>
+</section>
+<section id="get-the-test-data">
+<h2>Get the test data<a class="headerlink" href="#get-the-test-data" title="Permalink to this heading"></a></h2>
+<p>We use the test wave
+from <a class="reference external" href="https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html">CTC FORCED ALIGNMENT API TUTORIAL</a></p>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">torchaudio</span>
+
+<span class="c1"># Download test wave</span>
+<span class="n">speech_file</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">utils</span><span class="o">.</span><span class="n">download_asset</span><span class="p">(</span><span class="s2">&quot;tutorial-assets/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav&quot;</span><span class="p">)</span>
+<span class="nb">print</span><span class="p">(</span><span class="n">speech_file</span><span class="p">)</span>
+<span class="n">waveform</span><span class="p">,</span> <span class="n">sr</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">load</span><span class="p">(</span><span class="n">speech_file</span><span class="p">)</span>
+<span class="n">transcript</span> <span class="o">=</span> <span class="s2">&quot;i had that curiosity beside me at this moment&quot;</span><span class="o">.</span><span class="n">split</span><span class="p">()</span>
+<span class="nb">print</span><span class="p">(</span><span class="n">waveform</span><span class="o">.</span><span class="n">shape</span><span class="p">,</span> <span class="n">sr</span><span class="p">)</span>
+
+<span class="k">assert</span> <span class="n">waveform</span><span class="o">.</span><span class="n">ndim</span> <span class="o">==</span> <span class="mi">2</span>
+<span class="k">assert</span> <span class="n">waveform</span><span class="o">.</span><span class="n">shape</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="mi">1</span>
+<span class="k">assert</span> <span class="n">sr</span> <span class="o">==</span> <span class="mi">16000</span>
+</pre></div>
+</div>
+<p>The test wave is downloaded to:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span>$HOME/.cache/torch/hub/torchaudio/tutorial-assets/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav
+</pre></div>
+</div>
+<table>
+  <tr>
+    <th>Wave filename</th>
+    <th>Content</th>
+    <th>Text</th>
+  </tr>
+  <tr>
+    <td>Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav</td>
+    <td>
+     <audio title="Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+    <td>
+      i had that curiosity beside me at this moment
+    </td>
+  </tr>
+</table><p>We use the test model
+from <a class="reference external" href="https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html">CTC FORCED ALIGNMENT API TUTORIAL</a></p>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">torch</span>
+
+<span class="n">bundle</span> <span class="o">=</span> <span class="n">torchaudio</span><span class="o">.</span><span class="n">pipelines</span><span class="o">.</span><span class="n">MMS_FA</span>
+
+<span class="n">device</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">device</span><span class="p">(</span><span class="s2">&quot;cuda&quot;</span> <span class="k">if</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">is_available</span><span class="p">()</span> <span class="k">else</span> <span class="s2">&quot;cpu&quot;</span><span class="p">)</span>
+<span class="n">model</span> <span class="o">=</span> <span class="n">bundle</span><span class="o">.</span><span class="n">get_model</span><span class="p">(</span><span class="n">with_star</span><span class="o">=</span><span class="kc">False</span><span class="p">)</span><span class="o">.</span><span class="n">to</span><span class="p">(</span><span class="n">device</span><span class="p">)</span>
+</pre></div>
+</div>
+<p>The model is downloaded to:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span>$HOME/.cache/torch/hub/checkpoints/model.pt
+</pre></div>
+</div>
+</section>
+<section id="compute-log-probs">
+<h2>Compute log_probs<a class="headerlink" href="#compute-log-probs" title="Permalink to this heading"></a></h2>
+<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>with<span class="w"> </span>torch.inference_mode<span class="o">()</span>:
+<span class="w">    </span>emission,<span class="w"> </span><span class="nv">_</span><span class="w"> </span><span class="o">=</span><span class="w"> </span>model<span class="o">(</span>waveform.to<span class="o">(</span>device<span class="o">))</span>
+<span class="w">    </span>print<span class="o">(</span>emission.shape<span class="o">)</span>
+</pre></div>
+</div>
+<p>It should print:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">torch</span><span class="o">.</span><span class="n">Size</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">169</span><span class="p">,</span> <span class="mi">28</span><span class="p">])</span>
+</pre></div>
+</div>
+</section>
+<section id="create-token2id-and-id2token">
+<h2>Create token2id and id2token<a class="headerlink" href="#create-token2id-and-id2token" title="Permalink to this heading"></a></h2>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">token2id</span> <span class="o">=</span> <span class="n">bundle</span><span class="o">.</span><span class="n">get_dict</span><span class="p">(</span><span class="n">star</span><span class="o">=</span><span class="kc">None</span><span class="p">)</span>
+<span class="n">id2token</span> <span class="o">=</span> <span class="p">{</span><span class="n">i</span><span class="p">:</span><span class="n">t</span> <span class="k">for</span> <span class="n">t</span><span class="p">,</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">token2id</span><span class="o">.</span><span class="n">items</span><span class="p">()}</span>
+<span class="n">token2id</span><span class="p">[</span><span class="s2">&quot;&lt;eps&gt;&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
+<span class="k">del</span> <span class="n">token2id</span><span class="p">[</span><span class="s2">&quot;-&quot;</span><span class="p">]</span>
+</pre></div>
+</div>
+</section>
+<section id="create-word2id-and-id2word">
+<h2>Create word2id and id2word<a class="headerlink" href="#create-word2id-and-id2word" title="Permalink to this heading"></a></h2>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">words</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">set</span><span class="p">(</span><span class="n">transcript</span><span class="p">))</span>
+<span class="n">word2id</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">()</span>
+<span class="n">word2id</span><span class="p">[</span><span class="s1">&#39;eps&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
+<span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">w</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">words</span><span class="p">):</span>
+  <span class="n">word2id</span><span class="p">[</span><span class="n">w</span><span class="p">]</span> <span class="o">=</span> <span class="n">i</span> <span class="o">+</span> <span class="mi">1</span>
+
+<span class="n">id2word</span> <span class="o">=</span> <span class="p">{</span><span class="n">i</span><span class="p">:</span><span class="n">w</span> <span class="k">for</span> <span class="n">w</span><span class="p">,</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">word2id</span><span class="o">.</span><span class="n">items</span><span class="p">()}</span>
+</pre></div>
+</div>
+<p>Note that we only use words from the transcript of the test wave.</p>
+</section>
+<section id="generate-lexicon-related-files">
+<h2>Generate lexicon-related files<a class="headerlink" href="#generate-lexicon-related-files" title="Permalink to this heading"></a></h2>
+<p>We use the code below to generate the following 4 files:</p>
+<blockquote>
+<div><ul class="simple">
+<li><p><code class="docutils literal notranslate"><span class="pre">lexicon.txt</span></code></p></li>
+<li><p><code class="docutils literal notranslate"><span class="pre">tokens.txt</span></code></p></li>
+<li><p><code class="docutils literal notranslate"><span class="pre">words.txt</span></code></p></li>
+<li><p><code class="docutils literal notranslate"><span class="pre">lexicon_disambig.txt</span></code></p></li>
+</ul>
+</div></blockquote>
+<div class="admonition caution">
+<p class="admonition-title">Caution</p>
+<p><code class="docutils literal notranslate"><span class="pre">words.txt</span></code> contains only words from the transcript of the test wave.</p>
+</div>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">prepare_lang</span> <span class="kn">import</span> <span class="n">add_disambig_symbols</span>
+
+<span class="n">lexicon</span> <span class="o">=</span> <span class="p">[(</span><span class="n">w</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">w</span><span class="p">))</span> <span class="k">for</span> <span class="n">w</span> <span class="ow">in</span> <span class="n">word2id</span> <span class="k">if</span> <span class="n">w</span> <span class="o">!=</span> <span class="s2">&quot;eps&quot;</span><span class="p">]</span>
+<span class="n">lexicon_disambig</span><span class="p">,</span> <span class="n">max_disambig_id</span> <span class="o">=</span> <span class="n">add_disambig_symbols</span><span class="p">(</span><span class="n">lexicon</span><span class="p">)</span>
+
+<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">&#39;lexicon.txt&#39;</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">,</span> <span class="n">encoding</span><span class="o">=</span><span class="s1">&#39;utf-8&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
+  <span class="k">for</span> <span class="n">w</span><span class="p">,</span> <span class="n">tokens</span> <span class="ow">in</span> <span class="n">lexicon</span><span class="p">:</span>
+    <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">w</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="s1">&#39; &#39;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">tokens</span><span class="p">)</span><span class="si">}</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
+
+<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">&#39;lexicon_disambig.txt&#39;</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">,</span> <span class="n">encoding</span><span class="o">=</span><span class="s1">&#39;utf-8&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
+  <span class="k">for</span> <span class="n">w</span><span class="p">,</span> <span class="n">tokens</span> <span class="ow">in</span> <span class="n">lexicon_disambig</span><span class="p">:</span>
+    <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">w</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="s1">&#39; &#39;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">tokens</span><span class="p">)</span><span class="si">}</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
+
+<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">&#39;tokens.txt&#39;</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">,</span> <span class="n">encoding</span><span class="o">=</span><span class="s1">&#39;utf-8&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
+  <span class="k">for</span> <span class="n">t</span><span class="p">,</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">token2id</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
+    <span class="k">if</span> <span class="n">t</span> <span class="o">==</span> <span class="s1">&#39;-&#39;</span><span class="p">:</span>
+      <span class="n">t</span> <span class="o">=</span> <span class="s2">&quot;&lt;eps&gt;&quot;</span>
+    <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">t</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="n">i</span><span class="si">}</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
+
+  <span class="k">for</span> <span class="n">k</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">max_disambig_id</span> <span class="o">+</span> <span class="mi">2</span><span class="p">):</span>
+    <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;#</span><span class="si">{</span><span class="n">k</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="nb">len</span><span class="p">(</span><span class="n">token2id</span><span class="p">)</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">k</span><span class="si">}</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
+
+<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">&#39;words.txt&#39;</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">,</span> <span class="n">encoding</span><span class="o">=</span><span class="s1">&#39;utf-8&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
+  <span class="k">for</span> <span class="n">w</span><span class="p">,</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">word2id</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
+    <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">w</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="n">i</span><span class="si">}</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
+  <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;#0 </span><span class="si">{</span><span class="nb">len</span><span class="p">(</span><span class="n">word2id</span><span class="p">)</span><span class="si">}</span><span class="se">\n</span><span class="s1">&#39;</span><span class="p">)</span>
+</pre></div>
+</div>
+<p>To give you an idea about what the generated files look like:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">head</span> <span class="o">-</span><span class="n">n</span> <span class="mi">50</span> <span class="n">lexicon</span><span class="o">.</span><span class="n">txt</span> <span class="n">lexicon_disambig</span><span class="o">.</span><span class="n">txt</span> <span class="n">tokens</span><span class="o">.</span><span class="n">txt</span> <span class="n">words</span><span class="o">.</span><span class="n">txt</span>
+</pre></div>
+</div>
+<p>prints:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="o">==&gt;</span> <span class="n">lexicon</span><span class="o">.</span><span class="n">txt</span> <span class="o">&lt;==</span>
+<span class="n">moment</span> <span class="n">m</span> <span class="n">o</span> <span class="n">m</span> <span class="n">e</span> <span class="n">n</span> <span class="n">t</span>
+<span class="n">beside</span> <span class="n">b</span> <span class="n">e</span> <span class="n">s</span> <span class="n">i</span> <span class="n">d</span> <span class="n">e</span>
+<span class="n">i</span> <span class="n">i</span>
+<span class="n">this</span> <span class="n">t</span> <span class="n">h</span> <span class="n">i</span> <span class="n">s</span>
+<span class="n">curiosity</span> <span class="n">c</span> <span class="n">u</span> <span class="n">r</span> <span class="n">i</span> <span class="n">o</span> <span class="n">s</span> <span class="n">i</span> <span class="n">t</span> <span class="n">y</span>
+<span class="n">had</span> <span class="n">h</span> <span class="n">a</span> <span class="n">d</span>
+<span class="n">that</span> <span class="n">t</span> <span class="n">h</span> <span class="n">a</span> <span class="n">t</span>
+<span class="n">at</span> <span class="n">a</span> <span class="n">t</span>
+<span class="n">me</span> <span class="n">m</span> <span class="n">e</span>
+
+<span class="o">==&gt;</span> <span class="n">lexicon_disambig</span><span class="o">.</span><span class="n">txt</span> <span class="o">&lt;==</span>
+<span class="n">moment</span> <span class="n">m</span> <span class="n">o</span> <span class="n">m</span> <span class="n">e</span> <span class="n">n</span> <span class="n">t</span>
+<span class="n">beside</span> <span class="n">b</span> <span class="n">e</span> <span class="n">s</span> <span class="n">i</span> <span class="n">d</span> <span class="n">e</span>
+<span class="n">i</span> <span class="n">i</span>
+<span class="n">this</span> <span class="n">t</span> <span class="n">h</span> <span class="n">i</span> <span class="n">s</span>
+<span class="n">curiosity</span> <span class="n">c</span> <span class="n">u</span> <span class="n">r</span> <span class="n">i</span> <span class="n">o</span> <span class="n">s</span> <span class="n">i</span> <span class="n">t</span> <span class="n">y</span>
+<span class="n">had</span> <span class="n">h</span> <span class="n">a</span> <span class="n">d</span>
+<span class="n">that</span> <span class="n">t</span> <span class="n">h</span> <span class="n">a</span> <span class="n">t</span>
+<span class="n">at</span> <span class="n">a</span> <span class="n">t</span>
+<span class="n">me</span> <span class="n">m</span> <span class="n">e</span>
+
+<span class="o">==&gt;</span> <span class="n">tokens</span><span class="o">.</span><span class="n">txt</span> <span class="o">&lt;==</span>
+<span class="n">a</span> <span class="mi">1</span>
+<span class="n">i</span> <span class="mi">2</span>
+<span class="n">e</span> <span class="mi">3</span>
+<span class="n">n</span> <span class="mi">4</span>
+<span class="n">o</span> <span class="mi">5</span>
+<span class="n">u</span> <span class="mi">6</span>
+<span class="n">t</span> <span class="mi">7</span>
+<span class="n">s</span> <span class="mi">8</span>
+<span class="n">r</span> <span class="mi">9</span>
+<span class="n">m</span> <span class="mi">10</span>
+<span class="n">k</span> <span class="mi">11</span>
+<span class="n">l</span> <span class="mi">12</span>
+<span class="n">d</span> <span class="mi">13</span>
+<span class="n">g</span> <span class="mi">14</span>
+<span class="n">h</span> <span class="mi">15</span>
+<span class="n">y</span> <span class="mi">16</span>
+<span class="n">b</span> <span class="mi">17</span>
+<span class="n">p</span> <span class="mi">18</span>
+<span class="n">w</span> <span class="mi">19</span>
+<span class="n">c</span> <span class="mi">20</span>
+<span class="n">v</span> <span class="mi">21</span>
+<span class="n">j</span> <span class="mi">22</span>
+<span class="n">z</span> <span class="mi">23</span>
+<span class="n">f</span> <span class="mi">24</span>
+<span class="s1">&#39; 25</span>
+<span class="n">q</span> <span class="mi">26</span>
+<span class="n">x</span> <span class="mi">27</span>
+<span class="o">&lt;</span><span class="n">eps</span><span class="o">&gt;</span> <span class="mi">0</span>
+<span class="c1">#0 28</span>
+<span class="c1">#1 29</span>
+
+<span class="o">==&gt;</span> <span class="n">words</span><span class="o">.</span><span class="n">txt</span> <span class="o">&lt;==</span>
+<span class="n">eps</span> <span class="mi">0</span>
+<span class="n">moment</span> <span class="mi">1</span>
+<span class="n">beside</span> <span class="mi">2</span>
+<span class="n">i</span> <span class="mi">3</span>
+<span class="n">this</span> <span class="mi">4</span>
+<span class="n">curiosity</span> <span class="mi">5</span>
+<span class="n">had</span> <span class="mi">6</span>
+<span class="n">that</span> <span class="mi">7</span>
+<span class="n">at</span> <span class="mi">8</span>
+<span class="n">me</span> <span class="mi">9</span>
+<span class="c1">#0 10</span>
+</pre></div>
+</div>
+<div class="admonition note">
+<p class="admonition-title">Note</p>
+<p>This test model uses characters as modeling unit. If you use other types of
+modeling unit, the same code can be used without any change.</p>
+</div>
+</section>
+<section id="convert-transcript-to-an-fst-graph">
+<h2>Convert transcript to an FST graph<a class="headerlink" href="#convert-transcript-to-an-fst-graph" title="Permalink to this heading"></a></h2>
+<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>egs/librispeech/ASR/local/prepare_lang_fst.py<span class="w"> </span>--lang-dir<span class="w"> </span>./
+</pre></div>
+</div>
+<p>The above command should generate two files <code class="docutils literal notranslate"><span class="pre">H.fst</span></code> and <code class="docutils literal notranslate"><span class="pre">HL.fst</span></code>. We will
+use <code class="docutils literal notranslate"><span class="pre">HL.fst</span></code> below:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="o">-</span><span class="n">rw</span><span class="o">-</span><span class="n">r</span><span class="o">--</span><span class="n">r</span><span class="o">--</span> <span class="mi">1</span> <span class="n">root</span> <span class="n">root</span>  <span class="mi">13</span><span class="n">K</span> <span class="n">Jun</span> <span class="mi">12</span> <span class="mi">08</span><span class="p">:</span><span class="mi">28</span> <span class="n">H</span><span class="o">.</span><span class="n">fst</span>
+<span class="o">-</span><span class="n">rw</span><span class="o">-</span><span class="n">r</span><span class="o">--</span><span class="n">r</span><span class="o">--</span> <span class="mi">1</span> <span class="n">root</span> <span class="n">root</span> <span class="mf">3.7</span><span class="n">K</span> <span class="n">Jun</span> <span class="mi">12</span> <span class="mi">08</span><span class="p">:</span><span class="mi">28</span> <span class="n">HL</span><span class="o">.</span><span class="n">fst</span>
+</pre></div>
+</div>
+</section>
+<section id="force-aligner">
+<h2>Force aligner<a class="headerlink" href="#force-aligner" title="Permalink to this heading"></a></h2>
+<p>Now, everything is ready. We can use the following code to get forced alignments.</p>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">kaldi_decoder</span> <span class="kn">import</span> <span class="n">DecodableCtc</span><span class="p">,</span> <span class="n">FasterDecoder</span><span class="p">,</span> <span class="n">FasterDecoderOptions</span>
+<span class="kn">import</span> <span class="nn">kaldifst</span>
+
+<span class="k">def</span> <span class="nf">force_align</span><span class="p">():</span>
+    <span class="n">HL</span> <span class="o">=</span> <span class="n">kaldifst</span><span class="o">.</span><span class="n">StdVectorFst</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="s2">&quot;./HL.fst&quot;</span><span class="p">)</span>
+    <span class="n">decodable</span> <span class="o">=</span> <span class="n">DecodableCtc</span><span class="p">(</span><span class="n">emission</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">contiguous</span><span class="p">()</span><span class="o">.</span><span class="n">cpu</span><span class="p">()</span><span class="o">.</span><span class="n">numpy</span><span class="p">())</span>
+    <span class="n">decoder_opts</span> <span class="o">=</span> <span class="n">FasterDecoderOptions</span><span class="p">(</span><span class="n">max_active</span><span class="o">=</span><span class="mi">3000</span><span class="p">)</span>
+    <span class="n">decoder</span> <span class="o">=</span> <span class="n">FasterDecoder</span><span class="p">(</span><span class="n">HL</span><span class="p">,</span> <span class="n">decoder_opts</span><span class="p">)</span>
+    <span class="n">decoder</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="n">decodable</span><span class="p">)</span>
+    <span class="k">if</span> <span class="ow">not</span> <span class="n">decoder</span><span class="o">.</span><span class="n">reached_final</span><span class="p">():</span>
+        <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;failed to decode xxx&quot;</span><span class="p">)</span>
+        <span class="k">return</span> <span class="kc">None</span>
+    <span class="n">ok</span><span class="p">,</span> <span class="n">best_path</span> <span class="o">=</span> <span class="n">decoder</span><span class="o">.</span><span class="n">get_best_path</span><span class="p">()</span>
+
+    <span class="p">(</span>
+        <span class="n">ok</span><span class="p">,</span>
+        <span class="n">isymbols_out</span><span class="p">,</span>
+        <span class="n">osymbols_out</span><span class="p">,</span>
+        <span class="n">total_weight</span><span class="p">,</span>
+    <span class="p">)</span> <span class="o">=</span> <span class="n">kaldifst</span><span class="o">.</span><span class="n">get_linear_symbol_sequence</span><span class="p">(</span><span class="n">best_path</span><span class="p">)</span>
+    <span class="k">if</span> <span class="ow">not</span> <span class="n">ok</span><span class="p">:</span>
+        <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;failed to get linear symbol sequence for xxx&quot;</span><span class="p">)</span>
+        <span class="k">return</span> <span class="kc">None</span>
+
+    <span class="c1"># We need to use i-1 here since we have incremented tokens during</span>
+    <span class="c1"># HL construction</span>
+    <span class="n">alignment</span> <span class="o">=</span> <span class="p">[</span><span class="n">i</span><span class="o">-</span><span class="mi">1</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">isymbols_out</span><span class="p">]</span>
+    <span class="k">return</span> <span class="n">alignment</span>
+
+<span class="n">alignment</span> <span class="o">=</span> <span class="n">force_align</span><span class="p">()</span>
+
+<span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">a</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">alignment</span><span class="p">):</span>
+  <span class="nb">print</span><span class="p">(</span><span class="n">i</span><span class="p">,</span> <span class="n">id2token</span><span class="p">[</span><span class="n">a</span><span class="p">])</span>
+</pre></div>
+</div>
+<p>The output should be identical to
+<a class="reference external" href="https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html#frame-level-alignments">https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html#frame-level-alignments</a>.</p>
+<p>For ease of reference, we list the output below:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="mi">0</span> <span class="o">-</span>
+<span class="mi">1</span> <span class="o">-</span>
+<span class="mi">2</span> <span class="o">-</span>
+<span class="mi">3</span> <span class="o">-</span>
+<span class="mi">4</span> <span class="o">-</span>
+<span class="mi">5</span> <span class="o">-</span>
+<span class="mi">6</span> <span class="o">-</span>
+<span class="mi">7</span> <span class="o">-</span>
+<span class="mi">8</span> <span class="o">-</span>
+<span class="mi">9</span> <span class="o">-</span>
+<span class="mi">10</span> <span class="o">-</span>
+<span class="mi">11</span> <span class="o">-</span>
+<span class="mi">12</span> <span class="o">-</span>
+<span class="mi">13</span> <span class="o">-</span>
+<span class="mi">14</span> <span class="o">-</span>
+<span class="mi">15</span> <span class="o">-</span>
+<span class="mi">16</span> <span class="o">-</span>
+<span class="mi">17</span> <span class="o">-</span>
+<span class="mi">18</span> <span class="o">-</span>
+<span class="mi">19</span> <span class="o">-</span>
+<span class="mi">20</span> <span class="o">-</span>
+<span class="mi">21</span> <span class="o">-</span>
+<span class="mi">22</span> <span class="o">-</span>
+<span class="mi">23</span> <span class="o">-</span>
+<span class="mi">24</span> <span class="o">-</span>
+<span class="mi">25</span> <span class="o">-</span>
+<span class="mi">26</span> <span class="o">-</span>
+<span class="mi">27</span> <span class="o">-</span>
+<span class="mi">28</span> <span class="o">-</span>
+<span class="mi">29</span> <span class="o">-</span>
+<span class="mi">30</span> <span class="o">-</span>
+<span class="mi">31</span> <span class="o">-</span>
+<span class="mi">32</span> <span class="n">i</span>
+<span class="mi">33</span> <span class="o">-</span>
+<span class="mi">34</span> <span class="o">-</span>
+<span class="mi">35</span> <span class="n">h</span>
+<span class="mi">36</span> <span class="n">h</span>
+<span class="mi">37</span> <span class="n">a</span>
+<span class="mi">38</span> <span class="o">-</span>
+<span class="mi">39</span> <span class="o">-</span>
+<span class="mi">40</span> <span class="o">-</span>
+<span class="mi">41</span> <span class="n">d</span>
+<span class="mi">42</span> <span class="o">-</span>
+<span class="mi">43</span> <span class="o">-</span>
+<span class="mi">44</span> <span class="n">t</span>
+<span class="mi">45</span> <span class="n">h</span>
+<span class="mi">46</span> <span class="o">-</span>
+<span class="mi">47</span> <span class="n">a</span>
+<span class="mi">48</span> <span class="o">-</span>
+<span class="mi">49</span> <span class="o">-</span>
+<span class="mi">50</span> <span class="n">t</span>
+<span class="mi">51</span> <span class="o">-</span>
+<span class="mi">52</span> <span class="o">-</span>
+<span class="mi">53</span> <span class="o">-</span>
+<span class="mi">54</span> <span class="n">c</span>
+<span class="mi">55</span> <span class="o">-</span>
+<span class="mi">56</span> <span class="o">-</span>
+<span class="mi">57</span> <span class="o">-</span>
+<span class="mi">58</span> <span class="n">u</span>
+<span class="mi">59</span> <span class="n">u</span>
+<span class="mi">60</span> <span class="o">-</span>
+<span class="mi">61</span> <span class="o">-</span>
+<span class="mi">62</span> <span class="o">-</span>
+<span class="mi">63</span> <span class="n">r</span>
+<span class="mi">64</span> <span class="o">-</span>
+<span class="mi">65</span> <span class="n">i</span>
+<span class="mi">66</span> <span class="o">-</span>
+<span class="mi">67</span> <span class="o">-</span>
+<span class="mi">68</span> <span class="o">-</span>
+<span class="mi">69</span> <span class="o">-</span>
+<span class="mi">70</span> <span class="o">-</span>
+<span class="mi">71</span> <span class="o">-</span>
+<span class="mi">72</span> <span class="n">o</span>
+<span class="mi">73</span> <span class="o">-</span>
+<span class="mi">74</span> <span class="o">-</span>
+<span class="mi">75</span> <span class="o">-</span>
+<span class="mi">76</span> <span class="o">-</span>
+<span class="mi">77</span> <span class="o">-</span>
+<span class="mi">78</span> <span class="o">-</span>
+<span class="mi">79</span> <span class="n">s</span>
+<span class="mi">80</span> <span class="o">-</span>
+<span class="mi">81</span> <span class="o">-</span>
+<span class="mi">82</span> <span class="o">-</span>
+<span class="mi">83</span> <span class="n">i</span>
+<span class="mi">84</span> <span class="o">-</span>
+<span class="mi">85</span> <span class="n">t</span>
+<span class="mi">86</span> <span class="o">-</span>
+<span class="mi">87</span> <span class="o">-</span>
+<span class="mi">88</span> <span class="n">y</span>
+<span class="mi">89</span> <span class="o">-</span>
+<span class="mi">90</span> <span class="o">-</span>
+<span class="mi">91</span> <span class="o">-</span>
+<span class="mi">92</span> <span class="o">-</span>
+<span class="mi">93</span> <span class="n">b</span>
+<span class="mi">94</span> <span class="o">-</span>
+<span class="mi">95</span> <span class="n">e</span>
+<span class="mi">96</span> <span class="o">-</span>
+<span class="mi">97</span> <span class="o">-</span>
+<span class="mi">98</span> <span class="o">-</span>
+<span class="mi">99</span> <span class="o">-</span>
+<span class="mi">100</span> <span class="o">-</span>
+<span class="mi">101</span> <span class="n">s</span>
+<span class="mi">102</span> <span class="o">-</span>
+<span class="mi">103</span> <span class="o">-</span>
+<span class="mi">104</span> <span class="o">-</span>
+<span class="mi">105</span> <span class="o">-</span>
+<span class="mi">106</span> <span class="o">-</span>
+<span class="mi">107</span> <span class="o">-</span>
+<span class="mi">108</span> <span class="o">-</span>
+<span class="mi">109</span> <span class="o">-</span>
+<span class="mi">110</span> <span class="n">i</span>
+<span class="mi">111</span> <span class="o">-</span>
+<span class="mi">112</span> <span class="o">-</span>
+<span class="mi">113</span> <span class="n">d</span>
+<span class="mi">114</span> <span class="n">e</span>
+<span class="mi">115</span> <span class="o">-</span>
+<span class="mi">116</span> <span class="n">m</span>
+<span class="mi">117</span> <span class="o">-</span>
+<span class="mi">118</span> <span class="o">-</span>
+<span class="mi">119</span> <span class="n">e</span>
+<span class="mi">120</span> <span class="o">-</span>
+<span class="mi">121</span> <span class="o">-</span>
+<span class="mi">122</span> <span class="o">-</span>
+<span class="mi">123</span> <span class="o">-</span>
+<span class="mi">124</span> <span class="n">a</span>
+<span class="mi">125</span> <span class="o">-</span>
+<span class="mi">126</span> <span class="o">-</span>
+<span class="mi">127</span> <span class="n">t</span>
+<span class="mi">128</span> <span class="o">-</span>
+<span class="mi">129</span> <span class="n">t</span>
+<span class="mi">130</span> <span class="n">h</span>
+<span class="mi">131</span> <span class="o">-</span>
+<span class="mi">132</span> <span class="n">i</span>
+<span class="mi">133</span> <span class="o">-</span>
+<span class="mi">134</span> <span class="o">-</span>
+<span class="mi">135</span> <span class="o">-</span>
+<span class="mi">136</span> <span class="n">s</span>
+<span class="mi">137</span> <span class="o">-</span>
+<span class="mi">138</span> <span class="o">-</span>
+<span class="mi">139</span> <span class="o">-</span>
+<span class="mi">140</span> <span class="o">-</span>
+<span class="mi">141</span> <span class="n">m</span>
+<span class="mi">142</span> <span class="o">-</span>
+<span class="mi">143</span> <span class="o">-</span>
+<span class="mi">144</span> <span class="n">o</span>
+<span class="mi">145</span> <span class="o">-</span>
+<span class="mi">146</span> <span class="o">-</span>
+<span class="mi">147</span> <span class="o">-</span>
+<span class="mi">148</span> <span class="n">m</span>
+<span class="mi">149</span> <span class="o">-</span>
+<span class="mi">150</span> <span class="o">-</span>
+<span class="mi">151</span> <span class="n">e</span>
+<span class="mi">152</span> <span class="o">-</span>
+<span class="mi">153</span> <span class="n">n</span>
+<span class="mi">154</span> <span class="o">-</span>
+<span class="mi">155</span> <span class="n">t</span>
+<span class="mi">156</span> <span class="o">-</span>
+<span class="mi">157</span> <span class="o">-</span>
+<span class="mi">158</span> <span class="o">-</span>
+<span class="mi">159</span> <span class="o">-</span>
+<span class="mi">160</span> <span class="o">-</span>
+<span class="mi">161</span> <span class="o">-</span>
+<span class="mi">162</span> <span class="o">-</span>
+<span class="mi">163</span> <span class="o">-</span>
+<span class="mi">164</span> <span class="o">-</span>
+<span class="mi">165</span> <span class="o">-</span>
+<span class="mi">166</span> <span class="o">-</span>
+<span class="mi">167</span> <span class="o">-</span>
+<span class="mi">168</span> <span class="o">-</span>
+</pre></div>
+</div>
+<p>To merge tokens, we use:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">icefall.ctc</span> <span class="kn">import</span> <span class="n">merge_tokens</span>
+<span class="n">token_spans</span> <span class="o">=</span> <span class="n">merge_tokens</span><span class="p">(</span><span class="n">alignment</span><span class="p">)</span>
+<span class="k">for</span> <span class="n">span</span> <span class="ow">in</span> <span class="n">token_spans</span><span class="p">:</span>
+  <span class="nb">print</span><span class="p">(</span><span class="n">id2token</span><span class="p">[</span><span class="n">span</span><span class="o">.</span><span class="n">token</span><span class="p">],</span> <span class="n">span</span><span class="o">.</span><span class="n">start</span><span class="p">,</span> <span class="n">span</span><span class="o">.</span><span class="n">end</span><span class="p">)</span>
+</pre></div>
+</div>
+<p>The output is given below:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">i</span> <span class="mi">32</span> <span class="mi">33</span>
+<span class="n">h</span> <span class="mi">35</span> <span class="mi">37</span>
+<span class="n">a</span> <span class="mi">37</span> <span class="mi">38</span>
+<span class="n">d</span> <span class="mi">41</span> <span class="mi">42</span>
+<span class="n">t</span> <span class="mi">44</span> <span class="mi">45</span>
+<span class="n">h</span> <span class="mi">45</span> <span class="mi">46</span>
+<span class="n">a</span> <span class="mi">47</span> <span class="mi">48</span>
+<span class="n">t</span> <span class="mi">50</span> <span class="mi">51</span>
+<span class="n">c</span> <span class="mi">54</span> <span class="mi">55</span>
+<span class="n">u</span> <span class="mi">58</span> <span class="mi">60</span>
+<span class="n">r</span> <span class="mi">63</span> <span class="mi">64</span>
+<span class="n">i</span> <span class="mi">65</span> <span class="mi">66</span>
+<span class="n">o</span> <span class="mi">72</span> <span class="mi">73</span>
+<span class="n">s</span> <span class="mi">79</span> <span class="mi">80</span>
+<span class="n">i</span> <span class="mi">83</span> <span class="mi">84</span>
+<span class="n">t</span> <span class="mi">85</span> <span class="mi">86</span>
+<span class="n">y</span> <span class="mi">88</span> <span class="mi">89</span>
+<span class="n">b</span> <span class="mi">93</span> <span class="mi">94</span>
+<span class="n">e</span> <span class="mi">95</span> <span class="mi">96</span>
+<span class="n">s</span> <span class="mi">101</span> <span class="mi">102</span>
+<span class="n">i</span> <span class="mi">110</span> <span class="mi">111</span>
+<span class="n">d</span> <span class="mi">113</span> <span class="mi">114</span>
+<span class="n">e</span> <span class="mi">114</span> <span class="mi">115</span>
+<span class="n">m</span> <span class="mi">116</span> <span class="mi">117</span>
+<span class="n">e</span> <span class="mi">119</span> <span class="mi">120</span>
+<span class="n">a</span> <span class="mi">124</span> <span class="mi">125</span>
+<span class="n">t</span> <span class="mi">127</span> <span class="mi">128</span>
+<span class="n">t</span> <span class="mi">129</span> <span class="mi">130</span>
+<span class="n">h</span> <span class="mi">130</span> <span class="mi">131</span>
+<span class="n">i</span> <span class="mi">132</span> <span class="mi">133</span>
+<span class="n">s</span> <span class="mi">136</span> <span class="mi">137</span>
+<span class="n">m</span> <span class="mi">141</span> <span class="mi">142</span>
+<span class="n">o</span> <span class="mi">144</span> <span class="mi">145</span>
+<span class="n">m</span> <span class="mi">148</span> <span class="mi">149</span>
+<span class="n">e</span> <span class="mi">151</span> <span class="mi">152</span>
+<span class="n">n</span> <span class="mi">153</span> <span class="mi">154</span>
+<span class="n">t</span> <span class="mi">155</span> <span class="mi">156</span>
+</pre></div>
+</div>
+<p>All of the code below is copied and modified
+from <a class="reference external" href="https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html">https://pytorch.org/audio/main/tutorials/ctc_forced_alignment_api_tutorial.html</a>.</p>
+</section>
+<section id="segment-each-word-using-the-computed-alignments">
+<h2>Segment each word using the computed alignments<a class="headerlink" href="#segment-each-word-using-the-computed-alignments" title="Permalink to this heading"></a></h2>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">unflatten</span><span class="p">(</span><span class="n">list_</span><span class="p">,</span> <span class="n">lengths</span><span class="p">):</span>
+    <span class="k">assert</span> <span class="nb">len</span><span class="p">(</span><span class="n">list_</span><span class="p">)</span> <span class="o">==</span> <span class="nb">sum</span><span class="p">(</span><span class="n">lengths</span><span class="p">)</span>
+    <span class="n">i</span> <span class="o">=</span> <span class="mi">0</span>
+    <span class="n">ret</span> <span class="o">=</span> <span class="p">[]</span>
+    <span class="k">for</span> <span class="n">l</span> <span class="ow">in</span> <span class="n">lengths</span><span class="p">:</span>
+        <span class="n">ret</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">list_</span><span class="p">[</span><span class="n">i</span> <span class="p">:</span> <span class="n">i</span> <span class="o">+</span> <span class="n">l</span><span class="p">])</span>
+        <span class="n">i</span> <span class="o">+=</span> <span class="n">l</span>
+    <span class="k">return</span> <span class="n">ret</span>
+
+
+<span class="n">word_spans</span> <span class="o">=</span> <span class="n">unflatten</span><span class="p">(</span><span class="n">token_spans</span><span class="p">,</span> <span class="p">[</span><span class="nb">len</span><span class="p">(</span><span class="n">word</span><span class="p">)</span> <span class="k">for</span> <span class="n">word</span> <span class="ow">in</span> <span class="n">transcript</span><span class="p">])</span>
+<span class="nb">print</span><span class="p">(</span><span class="n">word_spans</span><span class="p">)</span>
+</pre></div>
+</div>
+<p>The output is:</p>
+<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">[[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">32</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">33</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">15</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">35</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">37</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">37</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">38</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">13</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">41</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">42</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">44</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">45</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">15</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">45</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">46</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">47</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">48</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">50</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">51</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">20</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">54</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">55</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">6</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">58</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">60</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">9</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">63</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">64</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">65</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">66</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">5</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">72</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">73</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">8</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">79</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">80</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">83</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">84</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">85</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">86</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">16</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">88</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">89</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">17</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">93</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">94</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">95</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">96</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">8</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">101</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">102</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">110</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">111</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">13</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">113</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">114</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">114</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">115</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">116</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">117</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">119</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">120</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">124</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">125</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">127</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">128</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">129</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">130</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">15</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">130</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">131</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">132</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">133</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">8</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">136</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">137</span><span class="p">)],</span>
+ <span class="p">[</span><span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">141</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">142</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">5</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">144</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">145</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">148</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">149</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">151</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">152</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">4</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">153</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">154</span><span class="p">),</span> <span class="n">TokenSpan</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="mi">155</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="mi">156</span><span class="p">)]</span>
+<span class="p">]</span>
+</pre></div>
+</div>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">spans</span><span class="p">,</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">,</span> <span class="n">sample_rate</span><span class="o">=</span><span class="n">bundle</span><span class="o">.</span><span class="n">sample_rate</span><span class="p">):</span>
+    <span class="n">ratio</span> <span class="o">=</span> <span class="n">waveform</span><span class="o">.</span><span class="n">size</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">num_frames</span>
+    <span class="n">x0</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">ratio</span> <span class="o">*</span> <span class="n">spans</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">start</span><span class="p">)</span>
+    <span class="n">x1</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">ratio</span> <span class="o">*</span> <span class="n">spans</span><span class="p">[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span><span class="o">.</span><span class="n">end</span><span class="p">)</span>
+    <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">transcript</span><span class="si">}</span><span class="s2"> </span><span class="si">{</span><span class="n">x0</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">sample_rate</span><span class="si">:</span><span class="s2">.3f</span><span class="si">}</span><span class="s2"> - </span><span class="si">{</span><span class="n">x1</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">sample_rate</span><span class="si">:</span><span class="s2">.3f</span><span class="si">}</span><span class="s2"> sec&quot;</span><span class="p">)</span>
+    <span class="n">segment</span> <span class="o">=</span> <span class="n">waveform</span><span class="p">[:,</span> <span class="n">x0</span><span class="p">:</span><span class="n">x1</span><span class="p">]</span>
+    <span class="k">return</span> <span class="n">IPython</span><span class="o">.</span><span class="n">display</span><span class="o">.</span><span class="n">Audio</span><span class="p">(</span><span class="n">segment</span><span class="o">.</span><span class="n">numpy</span><span class="p">(),</span> <span class="n">rate</span><span class="o">=</span><span class="n">sample_rate</span><span class="p">)</span>
+<span class="n">num_frames</span> <span class="o">=</span> <span class="n">emission</span><span class="o">.</span><span class="n">size</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
+</pre></div>
+</div>
+<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">2</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">2</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">3</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">3</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">4</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">4</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">5</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">5</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">6</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">6</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">7</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">7</span><span class="p">])</span>
+<span class="n">preview_word</span><span class="p">(</span><span class="n">waveform</span><span class="p">,</span> <span class="n">word_spans</span><span class="p">[</span><span class="mi">8</span><span class="p">],</span> <span class="n">num_frames</span><span class="p">,</span> <span class="n">transcript</span><span class="p">[</span><span class="mi">8</span><span class="p">])</span>
+</pre></div>
+</div>
+<p>The segmented wave of each word along with its time stamp is given below:</p>
+<table>
+  <tr>
+    <th>Word</th>
+    <th>Time</th>
+    <th>Wave</th>
+  </tr>
+  <tr>
+    <td>i</td>
+    <td>0.644 - 0.664 sec</td>
+    <td>
+     <audio title="i.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/i.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>had</td>
+    <td>0.704 - 0.845 sec</td>
+    <td>
+     <audio title="had.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/had.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>that</td>
+    <td>0.885 - 1.026 sec</td>
+    <td>
+     <audio title="that.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/that.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>curiosity</td>
+    <td>1.086 - 1.790 sec</td>
+    <td>
+     <audio title="curiosity.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/curiosity.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>beside</td>
+    <td>1.871 - 2.314 sec</td>
+    <td>
+     <audio title="beside.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/beside.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>me</td>
+    <td>2.334 - 2.414 sec</td>
+    <td>
+     <audio title="me.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/me.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>at</td>
+    <td>2.495 - 2.575 sec</td>
+    <td>
+     <audio title="at.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/at.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>this</td>
+    <td>2.595 - 2.756 sec</td>
+    <td>
+     <audio title="this.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/this.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+  <tr>
+    <td>moment</td>
+    <td>2.837 - 3.138 sec</td>
+    <td>
+     <audio title="moment.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/moment.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+  </tr>
+</table><p>We repost the whole wave below for ease of reference:</p>
+<table>
+  <tr>
+    <th>Wave filename</th>
+    <th>Content</th>
+    <th>Text</th>
+  </tr>
+  <tr>
+    <td>Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav</td>
+    <td>
+     <audio title="Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" controls="controls">
+           <source src="/icefall/_static/kaldi-align/Lab41-SRI-VOiCES-src-sp0307-ch127535-sg0042.wav" type="audio/wav">
+           Your browser does not support the <code>audio</code> element.
+     </audio>
+    </td>
+    <td>
+      i had that curiosity beside me at this moment
+    </td>
+  </tr>
+</table></section>
+<section id="summary">
+<h2>Summary<a class="headerlink" href="#summary" title="Permalink to this heading"></a></h2>
+<p>Congratulations! You have succeeded in using the FST-based approach to
+compute alignment of a test wave.</p>
+</section>
+</section>
+
+
+           </div>
+          </div>
+          <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
+        <a href="diff.html" class="btn btn-neutral float-left" title="Two approaches" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
+        <a href="k2-based.html" class="btn btn-neutral float-right" title="k2-based forced alignment" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
+    </div>
+
+  <hr/>
+
+  <div role="contentinfo">
+    <p>&#169; Copyright 2021, icefall development team.</p>
+  </div>
+
+  Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a
+    <a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a>
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+
+</body>
+</html>
--- a/genindex.html
+++ b/genindex.html
@ -48,6 +48,7 @@
 <li class="toctree-l1"><a class="reference internal" href="docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="recipes/index.html">Recipes</a></li>
--- a/huggingface/index.html
+++ b/huggingface/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/huggingface/pretrained-models.html
+++ b/huggingface/pretrained-models.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/huggingface/spaces.html
+++ b/huggingface/spaces.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/index.html
+++ b/index.html
@ -50,6 +50,7 @@
 <li class="toctree-l1"><a class="reference internal" href="docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="recipes/index.html">Recipes</a></li>
@ -137,6 +138,12 @@ speech recognition recipes using <a class="reference external" href="https://git
 <li class="toctree-l2"><a class="reference internal" href="model-export/export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="fst-based-forced-alignment/index.html">FST-based forced alignment</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="fst-based-forced-alignment/diff.html">Two approaches</a></li>
+<li class="toctree-l2"><a class="reference internal" href="fst-based-forced-alignment/kaldi-based.html">Kaldi-based forced alignment</a></li>
+<li class="toctree-l2"><a class="reference internal" href="fst-based-forced-alignment/k2-based.html">k2-based forced alignment</a></li>
+</ul>
+</li>
 </ul>
 </div>
 <div class="toctree-wrapper compound">
--- a/installation/index.html
+++ b/installation/index.html
@ -74,6 +74,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/export-model-state-dict.html
+++ b/model-export/export-model-state-dict.html
@ -64,6 +64,7 @@
 <li class="toctree-l2"><a class="reference internal" href="export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/export-ncnn-conv-emformer.html
+++ b/model-export/export-ncnn-conv-emformer.html
@ -72,6 +72,7 @@
 </li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
@ -125,8 +126,8 @@
 </div>
 <div class="admonition caution">
 <p class="admonition-title">Caution</p>
-<p>Please use a more recent version of PyTorch. For instance, <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">1.8</span></code>
-may <code class="docutils literal notranslate"><span class="pre">not</span></code> work.</p>
+<p><code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&gt;</span> <span class="pre">2.0</span></code> may not work. If you get errors while building pnnx, please switch
+to <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&lt;</span> <span class="pre">2.0</span></code>.</p>
 </div>
 <section id="download-the-pre-trained-model">
 <h2>1. Download the pre-trained model<a class="headerlink" href="#download-the-pre-trained-model" title="Permalink to this heading"></a></h2>
--- a/model-export/export-ncnn-lstm.html
+++ b/model-export/export-ncnn-lstm.html
@ -21,7 +21,7 @@
    <script src="../_static/js/theme.js"></script>
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
-    <link rel="next" title="Recipes" href="../recipes/index.html" />
+    <link rel="next" title="FST-based forced alignment" href="../fst-based-forced-alignment/index.html" />
    <link rel="prev" title="Export ConvEmformer transducer models to ncnn" href="export-ncnn-conv-emformer.html" /> 
 </head>

@ -72,6 +72,7 @@
 </li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
@ -121,8 +122,8 @@
 </div>
 <div class="admonition caution">
 <p class="admonition-title">Caution</p>
-<p>Please use a more recent version of PyTorch. For instance, <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">1.8</span></code>
-may <code class="docutils literal notranslate"><span class="pre">not</span></code> work.</p>
+<p><code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&gt;</span> <span class="pre">2.0</span></code> may not work. If you get errors while building pnnx, please switch
+to <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&lt;</span> <span class="pre">2.0</span></code>.</p>
 </div>
 <section id="download-the-pre-trained-model">
 <h2>1. Download the pre-trained model<a class="headerlink" href="#download-the-pre-trained-model" title="Permalink to this heading"></a></h2>
@ -806,7 +807,7 @@ with <code class="docutils literal notranslate"><span class="pre">int8</span></c
          </div>
          <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
        <a href="export-ncnn-conv-emformer.html" class="btn btn-neutral float-left" title="Export ConvEmformer transducer models to ncnn" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
-        <a href="../recipes/index.html" class="btn btn-neutral float-right" title="Recipes" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
+        <a href="../fst-based-forced-alignment/index.html" class="btn btn-neutral float-right" title="FST-based forced alignment" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
    </div>

  <hr/>
--- a/model-export/export-ncnn-zipformer.html
+++ b/model-export/export-ncnn-zipformer.html
@ -71,6 +71,7 @@
 </li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
@ -120,8 +121,8 @@
 </div>
 <div class="admonition caution">
 <p class="admonition-title">Caution</p>
-<p>Please use a more recent version of PyTorch. For instance, <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">1.8</span></code>
-may <code class="docutils literal notranslate"><span class="pre">not</span></code> work.</p>
+<p><code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&gt;</span> <span class="pre">2.0</span></code> may not work. If you get errors while building pnnx, please switch
+to <code class="docutils literal notranslate"><span class="pre">torch</span> <span class="pre">&lt;</span> <span class="pre">2.0</span></code>.</p>
 </div>
 <section id="download-the-pre-trained-model">
 <h2>1. Download the pre-trained model<a class="headerlink" href="#download-the-pre-trained-model" title="Permalink to this heading"></a></h2>
--- a/model-export/export-ncnn.html
+++ b/model-export/export-ncnn.html
@ -63,6 +63,7 @@
 </li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/export-onnx.html
+++ b/model-export/export-onnx.html
@ -65,6 +65,7 @@
 <li class="toctree-l2"><a class="reference internal" href="export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/export-with-torch-jit-script.html
+++ b/model-export/export-with-torch-jit-script.html
@ -63,6 +63,7 @@
 <li class="toctree-l2"><a class="reference internal" href="export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/export-with-torch-jit-trace.html
+++ b/model-export/export-with-torch-jit-trace.html
@ -63,6 +63,7 @@
 <li class="toctree-l2"><a class="reference internal" href="export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/model-export/index.html
+++ b/model-export/index.html
@ -58,6 +58,7 @@
 <li class="toctree-l2"><a class="reference internal" href="export-ncnn.html">Export to ncnn</a></li>
 </ul>
 </li>
+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul>
 <li class="toctree-l1"><a class="reference internal" href="../recipes/index.html">Recipes</a></li>
--- a/objects.inv
+++ b/objects.inv
--- a/recipes/Finetune/adapter/finetune_adapter.html
+++ b/recipes/Finetune/adapter/finetune_adapter.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Finetune/from_supervised/finetune_zipformer.html
+++ b/recipes/Finetune/from_supervised/finetune_zipformer.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Finetune/index.html
+++ b/recipes/Finetune/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/aishell/conformer_ctc.html
+++ b/recipes/Non-streaming-ASR/aishell/conformer_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/aishell/index.html
+++ b/recipes/Non-streaming-ASR/aishell/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/aishell/stateless_transducer.html
+++ b/recipes/Non-streaming-ASR/aishell/stateless_transducer.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/aishell/tdnn_lstm_ctc.html
+++ b/recipes/Non-streaming-ASR/aishell/tdnn_lstm_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/index.html
+++ b/recipes/Non-streaming-ASR/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/conformer_ctc.html
+++ b/recipes/Non-streaming-ASR/librispeech/conformer_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/distillation.html
+++ b/recipes/Non-streaming-ASR/librispeech/distillation.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/index.html
+++ b/recipes/Non-streaming-ASR/librispeech/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/pruned_transducer_stateless.html
+++ b/recipes/Non-streaming-ASR/librispeech/pruned_transducer_stateless.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/tdnn_lstm_ctc.html
+++ b/recipes/Non-streaming-ASR/librispeech/tdnn_lstm_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/zipformer_ctc_blankskip.html
+++ b/recipes/Non-streaming-ASR/librispeech/zipformer_ctc_blankskip.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/librispeech/zipformer_mmi.html
+++ b/recipes/Non-streaming-ASR/librispeech/zipformer_mmi.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/timit/index.html
+++ b/recipes/Non-streaming-ASR/timit/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/timit/tdnn_ligru_ctc.html
+++ b/recipes/Non-streaming-ASR/timit/tdnn_ligru_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/timit/tdnn_lstm_ctc.html
+++ b/recipes/Non-streaming-ASR/timit/tdnn_lstm_ctc.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/yesno/index.html
+++ b/recipes/Non-streaming-ASR/yesno/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Non-streaming-ASR/yesno/tdnn.html
+++ b/recipes/Non-streaming-ASR/yesno/tdnn.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/RNN-LM/index.html
+++ b/recipes/RNN-LM/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/RNN-LM/librispeech/lm-training.html
+++ b/recipes/RNN-LM/librispeech/lm-training.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/index.html
+++ b/recipes/Streaming-ASR/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/introduction.html
+++ b/recipes/Streaming-ASR/introduction.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/librispeech/index.html
+++ b/recipes/Streaming-ASR/librispeech/index.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/librispeech/lstm_pruned_stateless_transducer.html
+++ b/recipes/Streaming-ASR/librispeech/lstm_pruned_stateless_transducer.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../faqs.html">Frequently Asked Questions (FAQs)</a></li>
 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/librispeech/pruned_transducer_stateless.html
+++ b/recipes/Streaming-ASR/librispeech/pruned_transducer_stateless.html
@ -51,6 +51,7 @@
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+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
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 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/Streaming-ASR/librispeech/zipformer_transducer.html
+++ b/recipes/Streaming-ASR/librispeech/zipformer_transducer.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
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 <li class="toctree-l1"><a class="reference internal" href="../../../model-export/index.html">Model export</a></li>
+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
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--- a/recipes/TTS/index.html
+++ b/recipes/TTS/index.html
@ -51,6 +51,7 @@
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+<li class="toctree-l1"><a class="reference internal" href="../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../index.html">Recipes</a><ul class="current">
--- a/recipes/TTS/ljspeech/vits.html
+++ b/recipes/TTS/ljspeech/vits.html
@ -51,6 +51,7 @@
 <li class="toctree-l1"><a class="reference internal" href="../../../docker/index.html">Docker</a></li>
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+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
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--- a/recipes/TTS/vctk/vits.html
+++ b/recipes/TTS/vctk/vits.html
@ -51,6 +51,7 @@
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+<li class="toctree-l1"><a class="reference internal" href="../../../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
 </ul>
 <ul class="current">
 <li class="toctree-l1 current"><a class="reference internal" href="../../index.html">Recipes</a><ul class="current">
--- a/recipes/index.html
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@ -22,7 +22,7 @@
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    <link rel="next" title="Non Streaming ASR" href="Non-streaming-ASR/index.html" />
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+    <link rel="prev" title="k2-based forced alignment" href="../fst-based-forced-alignment/k2-based.html" /> 
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@ -51,6 +51,7 @@
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+<li class="toctree-l1"><a class="reference internal" href="../fst-based-forced-alignment/index.html">FST-based forced alignment</a></li>
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@ -136,7 +137,7 @@ Currently, we provide recipes for speech recognition, language model, and speech
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