klarkxy/hustoj
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
9b13c95e8a4889474d797b7c1d82b6045d766425
hustoj/web/python-docs/library/audioop.html
klarkxy 723430cade 增加python文档
2025-03-09 17:10:56 +08:00

470 lines
39 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="zh_CN">
<head>
<meta charset="utf-8" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" />
<title>audioop --- 处理原始音频数据 &#8212; Python 3.8.20 文档</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
<script id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
<script src="../_static/jquery.js"></script>
<script src="../_static/underscore.js"></script>
<script src="../_static/doctools.js"></script>
<script src="../_static/language_data.js"></script>
<script src="../_static/translations.js"></script>
<script src="../_static/sidebar.js"></script>
<link rel="search" type="application/opensearchdescription+xml"
title="在 Python 3.8.20 文档 中搜索"
href="../_static/opensearch.xml"/>
<link rel="author" title="关于这些文档" href="../about.html" />
<link rel="index" title="索引" href="../genindex.html" />
<link rel="search" title="搜索" href="../search.html" />
<link rel="copyright" title="版权所有" href="../copyright.html" />
<link rel="next" title="aifc --- 读写 AIFF 和 AIFC 文件" href="aifc.html" />
<link rel="prev" title="多媒体服务" href="mm.html" />
<link rel="canonical" href="https://docs.python.org/3/library/audioop.html" />
<style>
@media only screen {
table.full-width-table {
width: 100%;
}
}
</style>
<link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
<script type="text/javascript" src="../_static/copybutton.js"></script>
<script type="text/javascript" src="../_static/menu.js"></script>
</head>
<body>
<div class="mobile-nav">
<input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
<label for="menuToggler" class="toggler__label">
<span></span>
</label>
<nav class="nav-content" role="navigation">
<a href="https://www.python.org/" class="nav-logo">
<img src="../_static/py.svg" alt="Logo"/>
</a>
<div class="version_switcher_placeholder"></div>
<form role="search" class="search" action="../search.html" method="get">
<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
<path fill-rule="nonzero"
d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z" fill="#444"></path>
</svg>
<input type="text" name="q" aria-label="快速搜索"/>
<input type="submit" value="转向"/>
</form>
</nav>
<div class="menu-wrapper">
<nav class="menu" role="navigation" aria-label="main navigation">
<div class="language_switcher_placeholder"></div>
<h4>上一个主题</h4>
<p class="topless"><a href="mm.html"
title="上一章">多媒体服务</a></p>
<h4>下一个主题</h4>
<p class="topless"><a href="aifc.html"
title="下一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">aifc</span></code> --- 读写 AIFF 和 AIFC 文件</a></p>
<div role="note" aria-label="source link">
<h3>本页</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">报告 Bug</a></li>
<li>
<a href="https://github.com/python/cpython/blob/3.8/Doc/library/audioop.rst"
rel="nofollow">显示源代码
</a>
</li>
</ul>
</div>
</nav>
</div>
</div>
<div id="outdated-warning" style="padding: .5em; text-align: center; background-color: #FFBABA; color: #6A0E0E;">
这个文档所针对的是一个已不再受支持的 Python 旧版本。
你应当升级版本，并阅读
<a href="/3/library/audioop.html"> Python 当前稳定版本的文档</a>.
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>导航</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="总目录"
accesskey="I">索引</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python 模块索引"
>模块</a> |</li>
<li class="right" >
<a href="aifc.html" title="aifc --- 读写 AIFF 和 AIFC 文件"
accesskey="N">下一页</a> |</li>
<li class="right" >
<a href="mm.html" title="多媒体服务"
accesskey="P">上一页</a> |</li>
<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> &#187;</li>
<li class="switchers">
<div class="language_switcher_placeholder"></div>
<div class="version_switcher_placeholder"></div>
</li>
<li>
</li>
<li id="cpython-language-and-version">
<a href="../index.html">3.8.20 Documentation</a> &#187;
</li>
<li class="nav-item nav-item-1"><a href="index.html" >Python 标准库</a> &#187;</li>
<li class="nav-item nav-item-2"><a href="mm.html" accesskey="U">多媒体服务</a> &#187;</li>
<li class="right">
<div class="inline-search" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="快速搜索" aria-label="快速搜索" type="text" name="q" />
<input type="submit" value="转向" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
|
</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="module-audioop">
<span id="audioop-manipulate-raw-audio-data"></span><h1><a class="reference internal" href="#module-audioop" title="audioop: Manipulate raw audio data."><code class="xref py py-mod docutils literal notranslate"><span class="pre">audioop</span></code></a> --- 处理原始音频数据<a class="headerlink" href="#module-audioop" title="永久链接至标题"></a></h1>
<hr class="docutils" />
<p><a class="reference internal" href="#module-audioop" title="audioop: Manipulate raw audio data."><code class="xref py py-mod docutils literal notranslate"><span class="pre">audioop</span></code></a> 模块包含针对声音片段的一些有用操作。它操作的声音片段由 8、16、24 或 32 位宽的有符号整型样本组成，存储在 <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">类字节串对象</span></a> 中。除非特别说明，否则所有标量项目均为整数。</p>
<div class="versionchanged">
<p><span class="versionmodified changed">在 3.4 版更改: </span>增加了对 24 位样本的支持。现在，所有函数都接受任何 <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">类字节串对象</span></a>。而传入字符串会立即导致错误。</p>
</div>
<p id="index-0">本模块提供对 a-LAW、u-LAW 和 Intel/DVI ADPCM 编码的支持。</p>
<p>部分更复杂的操作仅接受 16 位样本，而其他操作始终需要样本大小（以字节为单位）作为该操作的参数。</p>
<p>此模块定义了下列变量和函数：</p>
<dl class="exception">
<dt id="audioop.error">
<em class="property">exception </em><code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">error</code><a class="headerlink" href="#audioop.error" title="永久链接至目标"></a></dt>
<dd><p>所有错误都会抛出此异常，比如样本的字节数未知等等。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.add">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">add</code><span class="sig-paren">(</span><em class="sig-param">fragment1</em>, <em class="sig-param">fragment2</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.add" title="永久链接至目标"></a></dt>
<dd><p>两个样本作为参数传入，返回一个片段，该片段是两个样本的和。<em>width</em> 是样本宽度（以字节为单位），可以取 <code class="docutils literal notranslate"><span class="pre">1</span></code>, <code class="docutils literal notranslate"><span class="pre">2</span></code>, <code class="docutils literal notranslate"><span class="pre">3</span></code> 或 <code class="docutils literal notranslate"><span class="pre">4</span></code>。两个片段的长度应相同。如果发生溢出，较长的样本将被截断。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.adpcm2lin">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">adpcm2lin</code><span class="sig-paren">(</span><em class="sig-param">adpcmfragment</em>, <em class="sig-param">width</em>, <em class="sig-param">state</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.adpcm2lin" title="永久链接至目标"></a></dt>
<dd><p>将 Intel/DVI ADPCM 编码的片段解码为线性片段。关于 ADPCM 编码的详情请参阅 <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate"><span class="pre">lin2adpcm()</span></code></a> 的描述。返回一个元组 <code class="docutils literal notranslate"><span class="pre">(sample,</span> <span class="pre">newstate)</span></code>，其中 sample 的位宽由 <em>width</em> 指定。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.alaw2lin">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">alaw2lin</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.alaw2lin" title="永久链接至目标"></a></dt>
<dd><p>将 a-LAW 编码的声音片段转换为线性编码声音片段。由于 a-LAW 编码样本始终为 8 位，因此这里的 <em>width</em> 仅指输出片段的样本位宽。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.avg">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">avg</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.avg" title="永久链接至目标"></a></dt>
<dd><p>返回片段中所有样本的平均值。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.avgpp">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">avgpp</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.avgpp" title="永久链接至目标"></a></dt>
<dd><p>返回片段中所有样本的平均峰峰值。由于没有进行过滤，因此该例程的实用性尚存疑。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.bias">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">bias</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">bias</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.bias" title="永久链接至目标"></a></dt>
<dd><p>返回一个片段，该片段由原始片段中的每个样本加上偏差组成。在溢出时样本会回卷 (wrap around)。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.byteswap">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">byteswap</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.byteswap" title="永久链接至目标"></a></dt>
<dd><p>“按字节交换”片段中的所有样本，返回修改后的片段。将大端序样本转换为小端序样本，反之亦然。</p>
<div class="versionadded">
<p><span class="versionmodified added">3.4 新版功能.</span></p>
</div>
</dd></dl>
<dl class="function">
<dt id="audioop.cross">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">cross</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.cross" title="永久链接至目标"></a></dt>
<dd><p>将片段作为参数传入，返回其中过零点的数量。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.findfactor">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">findfactor</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">reference</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.findfactor" title="永久链接至目标"></a></dt>
<dd><p>返回一个系数 <em>F</em> 使得 <code class="docutils literal notranslate"><span class="pre">rms(add(fragment,</span> <span class="pre">mul(reference,</span> <span class="pre">-F)))</span></code> 最小，即返回乘以 <em>reference</em> 后最匹配 <em>fragment</em> 的那个乘数。两个片段都应包含 2 字节宽的样本。</p>
<p>本例程所需的时间与 <code class="docutils literal notranslate"><span class="pre">len(fragment)</span></code> 成正比。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.findfit">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">findfit</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">reference</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.findfit" title="永久链接至目标"></a></dt>
<dd><p>尽可能尝试让 <em>reference</em> 匹配 <em>fragment</em> 的一部分（<em>fragment</em> 应较长）。从概念上讲，完成这些靠从 <em>fragment</em> 中取出切片，使用 <a class="reference internal" href="#audioop.findfactor" title="audioop.findfactor"><code class="xref py py-func docutils literal notranslate"><span class="pre">findfactor()</span></code></a> 计算最佳匹配，并最小化结果。两个片段都应包含 2 字节宽的样本。返回一个元组 <code class="docutils literal notranslate"><span class="pre">(offset,</span> <span class="pre">factor)</span></code>，其中 <em>offset</em> 是在 <em>fragment</em> 中的偏移量（整数），表示从此处开始最佳匹配，而 <em>factor</em> 是由 <a class="reference internal" href="#audioop.findfactor" title="audioop.findfactor"><code class="xref py py-func docutils literal notranslate"><span class="pre">findfactor()</span></code></a> 定义的因数（浮点数）。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.findmax">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">findmax</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">length</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.findmax" title="永久链接至目标"></a></dt>
<dd><p>在 <em>fragment</em> 中搜索所有长度为 <em>length</em> 的样本切片（不是字节！）中，能量最大的那一个切片，即返回 <em>i</em> 使得 <code class="docutils literal notranslate"><span class="pre">rms(fragment[i*2:(i+length)*2])</span></code> 最大。两个片段都应包含 2 字节宽的样本。</p>
<p>本例程所需的时间与 <code class="docutils literal notranslate"><span class="pre">len(fragment)</span></code> 成正比。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.getsample">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">getsample</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">index</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.getsample" title="永久链接至目标"></a></dt>
<dd><p>返回片段中样本索引 <em>index</em> 的值。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.lin2adpcm">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">lin2adpcm</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">state</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.lin2adpcm" title="永久链接至目标"></a></dt>
<dd><p>将样本转换为 4 位 Intel/DVI ADPCM 编码。ADPCM 编码是一种自适应编码方案，其中每个 4 比特数字是一个采样值与下一个采样值之间的差除以（不定的）步长。IMA 已选择使用 Intel/DVI ADPCM 算法，因此它很可能成为标准。</p>
<p><em>state</em> 是一个表示编码器状态的元组。编码器返回一个元组 <code class="docutils literal notranslate"><span class="pre">(adpcmfrag,</span> <span class="pre">newstate)</span></code>，而 <em>newstate</em> 要在下一次调用 <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate"><span class="pre">lin2adpcm()</span></code></a> 时传入。在初始调用中，可以将 <code class="docutils literal notranslate"><span class="pre">None</span></code> 作为 state 传递。<em>adpcmfrag</em> 是 ADPCM 编码的片段，每个字节打包了 2 个 4 比特值。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.lin2alaw">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">lin2alaw</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.lin2alaw" title="永久链接至目标"></a></dt>
<dd><p>将音频片段中的采样值转换为 a-LAW 编码，并将其作为字节对象返回。a-LAW 是一种音频编码格式，仅使用 8 位样本即可获得大约 13 位的动态范围。Sun 音频硬件等使用该编码。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.lin2lin">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">lin2lin</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">newwidth</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.lin2lin" title="永久链接至目标"></a></dt>
<dd><p>将采样在 1、2、3 和 4 字节格式之间转换。</p>
<div class="admonition note">
<p class="admonition-title">注解</p>
<p>在某些音频格式（如 .WAV 文件）中，16、24 和 32 位采样是有符号的，但 8 位采样是无符号的。因此，当将这些格式转换为 8 位宽采样时，还需使结果加上 128:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">new_frames</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">lin2lin</span><span class="p">(</span><span class="n">frames</span><span class="p">,</span> <span class="n">old_width</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="n">new_frames</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">bias</span><span class="p">(</span><span class="n">new_frames</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">128</span><span class="p">)</span>
</pre></div>
</div>
<p>反之，将 8 位宽的采样转换为 16、24 或 32 位时，必须采用相同的处理。</p>
</div>
</dd></dl>
<dl class="function">
<dt id="audioop.lin2ulaw">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">lin2ulaw</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.lin2ulaw" title="永久链接至目标"></a></dt>
<dd><p>将音频片段中的采样值转换为 u-LAW 编码，并将其作为字节对象返回。u-LAW 是一种音频编码格式，仅使用 8 位采样即可获得大约 14 位的动态范围。Sun 音频硬件等使用该编码。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.max">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">max</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.max" title="永久链接至目标"></a></dt>
<dd><p>返回片段中所有采样值的最大 <em>绝对值</em>。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.maxpp">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">maxpp</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.maxpp" title="永久链接至目标"></a></dt>
<dd><p>返回声音片段中的最大峰峰值。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.minmax">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">minmax</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.minmax" title="永久链接至目标"></a></dt>
<dd><p>返回声音片段中所有采样值的最小值和最大值组成的元组。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.mul">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">mul</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">factor</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.mul" title="永久链接至目标"></a></dt>
<dd><p>返回一个片段，该片段由原始片段中的每个采样值乘以浮点值 <em>factor</em> 组成。如果发生溢出，采样将被截断。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.ratecv">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">ratecv</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">nchannels</em>, <em class="sig-param">inrate</em>, <em class="sig-param">outrate</em>, <em class="sig-param">state</em><span class="optional">[</span>, <em class="sig-param">weightA</em><span class="optional">[</span>, <em class="sig-param">weightB</em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#audioop.ratecv" title="永久链接至目标"></a></dt>
<dd><p>转换输入片段的帧速率。</p>
<p><em>state</em> 是一个表示转换器状态的元组。转换器返回一个元组 <code class="docutils literal notranslate"><span class="pre">(newfragment,</span> <span class="pre">newstate)</span></code>，而 <em>newstate</em> 要在下一次调用 <a class="reference internal" href="#audioop.ratecv" title="audioop.ratecv"><code class="xref py py-func docutils literal notranslate"><span class="pre">ratecv()</span></code></a> 时传入。初始调用应传入 <code class="docutils literal notranslate"><span class="pre">None</span></code> 作为 state。</p>
<p>参数 <em>weightA</em> 和 <em>weightB</em> 是简单数字滤波器的参数，默认分别为 <code class="docutils literal notranslate"><span class="pre">1</span></code> 和 <code class="docutils literal notranslate"><span class="pre">0</span></code>。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.reverse">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">reverse</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.reverse" title="永久链接至目标"></a></dt>
<dd><p>将片段中的采样值反转，返回修改后的片段。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.rms">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">rms</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.rms" title="永久链接至目标"></a></dt>
<dd><p>返回片段的均方根值，即 <code class="docutils literal notranslate"><span class="pre">sqrt(sum(S_i^2)/n)</span></code>。</p>
<p>测量音频信号的能量。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.tomono">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">tomono</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">lfactor</em>, <em class="sig-param">rfactor</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.tomono" title="永久链接至目标"></a></dt>
<dd><p>将立体声片段转换为单声道片段。左通道乘以 <em>lfactor</em>，右通道乘以 <em>rfactor</em>，然后两个通道相加得到单声道信号。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.tostereo">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">tostereo</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em>, <em class="sig-param">lfactor</em>, <em class="sig-param">rfactor</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.tostereo" title="永久链接至目标"></a></dt>
<dd><p>由单声道片段生成立体声片段。立体声片段中的两对采样都是从单声道计算而来的，即左声道是乘以 <em>lfactor</em>，右声道是乘以 <em>rfactor</em>。</p>
</dd></dl>
<dl class="function">
<dt id="audioop.ulaw2lin">
<code class="sig-prename descclassname">audioop.</code><code class="sig-name descname">ulaw2lin</code><span class="sig-paren">(</span><em class="sig-param">fragment</em>, <em class="sig-param">width</em><span class="sig-paren">)</span><a class="headerlink" href="#audioop.ulaw2lin" title="永久链接至目标"></a></dt>
<dd><p>将 u-LAW 编码的声音片段转换为线性编码声音片段。由于 u-LAW 编码采样值始终为 8 位，因此这里的 <em>width</em> 仅指输出片段的采样位宽。</p>
</dd></dl>
<p>请注意，诸如 <a class="reference internal" href="#audioop.mul" title="audioop.mul"><code class="xref py py-func docutils literal notranslate"><span class="pre">mul()</span></code></a> 或 <a class="reference internal" href="#audioop.max" title="audioop.max"><code class="xref py py-func docutils literal notranslate"><span class="pre">max()</span></code></a> 之类的操作在单声道和立体声间没有区别，即所有采样都作相同处理。如果出现问题，应先将立体声片段拆分为两个单声道片段，之后再重组。以下是如何进行该操作的示例:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">mul_stereo</span><span class="p">(</span><span class="n">sample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="n">lfactor</span><span class="p">,</span> <span class="n">rfactor</span><span class="p">):</span>
<span class="n">lsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">tomono</span><span class="p">(</span><span class="n">sample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
<span class="n">rsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">tomono</span><span class="p">(</span><span class="n">sample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="n">lsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">mul</span><span class="p">(</span><span class="n">lsample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="n">lfactor</span><span class="p">)</span>
<span class="n">rsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">mul</span><span class="p">(</span><span class="n">rsample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="n">rfactor</span><span class="p">)</span>
<span class="n">lsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">tostereo</span><span class="p">(</span><span class="n">lsample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
<span class="n">rsample</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">tostereo</span><span class="p">(</span><span class="n">rsample</span><span class="p">,</span> <span class="n">width</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="k">return</span> <span class="n">audioop</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">lsample</span><span class="p">,</span> <span class="n">rsample</span><span class="p">,</span> <span class="n">width</span><span class="p">)</span>
</pre></div>
</div>
<p>如果使用 ADPCM 编码器构造网络数据包，并且希望协议是无状态的（即能够容忍数据包丢失），则不仅需要传输数据，还应该传输状态。请注意，必须将*初始*状态（传入 <a class="reference internal" href="#audioop.lin2adpcm" title="audioop.lin2adpcm"><code class="xref py py-func docutils literal notranslate"><span class="pre">lin2adpcm()</span></code></a> 的状态）发送给解码器，不能发送最终状态（编码器返回的状态）。如果要使用 <a class="reference internal" href="struct.html#struct.Struct" title="struct.Struct"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct.Struct</span></code></a> 以二进制保存状态，可以将第一个元素（预测值）用 16 位编码，将第二个元素（增量索引）用 8 位编码。</p>
<p>本 ADPCM 编码器从不与其他 ADPCM 编码器对立，仅针对自身。本开发者可能会误读标准，这种情况下它们将无法与相应标准互操作。</p>
<p>乍看之下 <code class="xref py py-func docutils literal notranslate"><span class="pre">find*()</span></code> 例程可能有些可笑。它们主要是用于回声消除，一种快速有效的方法是选取输出样本中能量最高的片段，在输入样本中定位该片段，然后从输入样本中减去整个输出样本:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">echocancel</span><span class="p">(</span><span class="n">outputdata</span><span class="p">,</span> <span class="n">inputdata</span><span class="p">):</span>
<span class="n">pos</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">findmax</span><span class="p">(</span><span class="n">outputdata</span><span class="p">,</span> <span class="mi">800</span><span class="p">)</span> <span class="c1"># one tenth second</span>
<span class="n">out_test</span> <span class="o">=</span> <span class="n">outputdata</span><span class="p">[</span><span class="n">pos</span><span class="o">*</span><span class="mi">2</span><span class="p">:]</span>
<span class="n">in_test</span> <span class="o">=</span> <span class="n">inputdata</span><span class="p">[</span><span class="n">pos</span><span class="o">*</span><span class="mi">2</span><span class="p">:]</span>
<span class="n">ipos</span><span class="p">,</span> <span class="n">factor</span> <span class="o">=</span> <span class="n">audioop</span><span class="o">.</span><span class="n">findfit</span><span class="p">(</span><span class="n">in_test</span><span class="p">,</span> <span class="n">out_test</span><span class="p">)</span>
<span class="c1"># Optional (for better cancellation):</span>
<span class="c1"># factor = audioop.findfactor(in_test[ipos*2:ipos*2+len(out_test)],</span>
<span class="c1"># out_test)</span>
<span class="n">prefill</span> <span class="o">=</span> <span class="s1">&#39;</span><span class="se">\0</span><span class="s1">&#39;</span><span class="o">*</span><span class="p">(</span><span class="n">pos</span><span class="o">+</span><span class="n">ipos</span><span class="p">)</span><span class="o">*</span><span class="mi">2</span>
<span class="n">postfill</span> <span class="o">=</span> <span class="s1">&#39;</span><span class="se">\0</span><span class="s1">&#39;</span><span class="o">*</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">inputdata</span><span class="p">)</span><span class="o">-</span><span class="nb">len</span><span class="p">(</span><span class="n">prefill</span><span class="p">)</span><span class="o">-</span><span class="nb">len</span><span class="p">(</span><span class="n">outputdata</span><span class="p">))</span>
<span class="n">outputdata</span> <span class="o">=</span> <span class="n">prefill</span> <span class="o">+</span> <span class="n">audioop</span><span class="o">.</span><span class="n">mul</span><span class="p">(</span><span class="n">outputdata</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="o">-</span><span class="n">factor</span><span class="p">)</span> <span class="o">+</span> <span class="n">postfill</span>
<span class="k">return</span> <span class="n">audioop</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">inputdata</span><span class="p">,</span> <span class="n">outputdata</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
</pre></div>
</div>
</section>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h4>上一个主题</h4>
<p class="topless"><a href="mm.html"
title="上一章">多媒体服务</a></p>
<h4>下一个主题</h4>
<p class="topless"><a href="aifc.html"
title="下一章"><code class="xref py py-mod docutils literal notranslate"><span class="pre">aifc</span></code> --- 读写 AIFF 和 AIFC 文件</a></p>
<div role="note" aria-label="source link">
<h3>本页</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">报告 Bug</a></li>
<li>
<a href="https://github.com/python/cpython/blob/3.8/Doc/library/audioop.rst"
rel="nofollow">显示源代码
</a>
</li>
</ul>
</div>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>导航</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="总目录"
>索引</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python 模块索引"
>模块</a> |</li>
<li class="right" >
<a href="aifc.html" title="aifc --- 读写 AIFF 和 AIFC 文件"
>下一页</a> |</li>
<li class="right" >
<a href="mm.html" title="多媒体服务"
>上一页</a> |</li>
<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> &#187;</li>
<li class="switchers">
<div class="language_switcher_placeholder"></div>
<div class="version_switcher_placeholder"></div>
</li>
<li>
</li>
<li id="cpython-language-and-version">
<a href="../index.html">3.8.20 Documentation</a> &#187;
</li>
<li class="nav-item nav-item-1"><a href="index.html" >Python 标准库</a> &#187;</li>
<li class="nav-item nav-item-2"><a href="mm.html" >多媒体服务</a> &#187;</li>
<li class="right">
<div class="inline-search" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="快速搜索" aria-label="快速搜索" type="text" name="q" />
<input type="submit" value="转向" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
|
</li>
</ul>
</div>
<div class="footer">
&copy; <a href="../copyright.html">版权所有</a> 2001-2024, Python Software Foundation.
<br />
This page is licensed under the Python Software Foundation License Version 2.
<br />
Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
<br />
<br />
The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>
<br />
<br />
最后更新于 12月 09, 2024.
<a href="https://docs.python.org/3/bugs.html">Found a bug</a>?
<br />
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 2.4.4.
</div>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink