mirror of
https://github.com/k2-fsa/icefall.git
synced 2025-08-09 10:02:22 +00:00
168 lines
8.7 KiB
HTML
168 lines
8.7 KiB
HTML
|
|
|
|
<!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>Decoding with language models — 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=e59714d7" />
|
|
|
|
|
|
<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="Shallow fusion for Transducer" href="shallow-fusion.html" />
|
|
<link rel="prev" title="Huggingface spaces" href="../huggingface/spaces.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>
|
|
<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"><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>
|
|
</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 class="current">
|
|
<li class="toctree-l1 current"><a class="current reference internal" href="#">Decoding with language models</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="shallow-fusion.html">Shallow fusion for Transducer</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="LODR.html">LODR for RNN Transducer</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="rescoring.html">LM rescoring for Transducer</a></li>
|
|
</ul>
|
|
</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>
|
|
<a href="../index.html">icefall</a>
|
|
</nav>
|
|
|
|
<div class="wy-nav-content">
|
|
<div class="rst-content">
|
|
<div role="navigation" aria-label="Page navigation">
|
|
<ul class="wy-breadcrumbs">
|
|
<li><a href="../index.html" class="icon icon-home" aria-label="Home"></a></li>
|
|
<li class="breadcrumb-item active">Decoding with language models</li>
|
|
<li class="wy-breadcrumbs-aside">
|
|
<a href="https://github.com/k2-fsa/icefall/blob/master/docs/source/decoding-with-langugage-models/index.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="decoding-with-language-models">
|
|
<h1>Decoding with language models<a class="headerlink" href="#decoding-with-language-models" title="Permalink to this heading"></a></h1>
|
|
<p>This section describes how to use external langugage models
|
|
during decoding to improve the WER of transducer models. To train an external language model,
|
|
please refer to this tutorial: <a class="reference internal" href="../recipes/RNN-LM/librispeech/lm-training.html#train-nnlm"><span class="std std-ref">Train an RNN language model</span></a>.</p>
|
|
<p>The following decoding methods with external langugage models are available:</p>
|
|
<table class="docutils align-default">
|
|
<colgroup>
|
|
<col style="width: 33.3%" />
|
|
<col style="width: 66.7%" />
|
|
</colgroup>
|
|
<thead>
|
|
<tr class="row-odd"><th class="head"><p>Decoding method</p></th>
|
|
<th class="head"><p>beam=4</p></th>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">modified_beam_search</span></code></p></td>
|
|
<td><p>Beam search (i.e. really n-best decoding, the “beam” is the value of n), similar to the original RNN-T paper. Note, this method does not use language model.</p></td>
|
|
</tr>
|
|
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">modified_beam_search_lm_shallow_fusion</span></code></p></td>
|
|
<td><p>As <code class="docutils literal notranslate"><span class="pre">modified_beam_search</span></code>, but interpolate RNN-T scores with language model scores, also known as shallow fusion</p></td>
|
|
</tr>
|
|
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">modified_beam_search_LODR</span></code></p></td>
|
|
<td><p>As <code class="docutils literal notranslate"><span class="pre">modified_beam_search_lm_shallow_fusion</span></code>, but subtract score of a (BPE-symbol-level) bigram backoff language model used as an approximation to the internal language model of RNN-T.</p></td>
|
|
</tr>
|
|
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">modified_beam_search_lm_rescore</span></code></p></td>
|
|
<td><p>As <code class="docutils literal notranslate"><span class="pre">modified_beam_search</span></code>, but rescore the n-best hypotheses with external language model (e.g. RNNLM) and re-rank them.</p></td>
|
|
</tr>
|
|
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">modified_beam_search_lm_rescore_LODR</span></code></p></td>
|
|
<td><p>As <code class="docutils literal notranslate"><span class="pre">modified_beam_search_lm_rescore</span></code>, but also subtract the score of a (BPE-symbol-level) bigram backoff language model during re-ranking.</p></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="toctree-wrapper compound">
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="shallow-fusion.html">Shallow fusion for Transducer</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="LODR.html">LODR for RNN Transducer</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="rescoring.html">LM rescoring for Transducer</a></li>
|
|
</ul>
|
|
</div>
|
|
</section>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
<footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
|
|
<a href="../huggingface/spaces.html" class="btn btn-neutral float-left" title="Huggingface spaces" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
|
|
<a href="shallow-fusion.html" class="btn btn-neutral float-right" title="Shallow fusion for Transducer" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
|
|
</div>
|
|
|
|
<hr/>
|
|
|
|
<div role="contentinfo">
|
|
<p>© 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>
|
|
provided by <a href="https://readthedocs.org">Read the Docs</a>.
|
|
|
|
|
|
</footer>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
</div>
|
|
<script>
|
|
jQuery(function () {
|
|
SphinxRtdTheme.Navigation.enable(true);
|
|
});
|
|
</script>
|
|
|
|
</body>
|
|
</html> |