Edit File: wave.html
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Multimedia Services</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="module-wave"> <span id="wave-read-and-write-wav-files"></span><h1>21.5. <a class="reference internal" href="#module-wave" title="wave: Provide an interface to the WAV sound format."><tt class="xref py py-mod docutils literal"><span class="pre">wave</span></tt></a> — Read and write WAV files<a class="headerlink" href="#module-wave" title="Permalink to this headline">¶</a></h1> <p><strong>Source code:</strong> <a class="reference external" href="http://hg.python.org/cpython/file/2.7/Lib/wave.py">Lib/wave.py</a></p> <hr class="docutils" /> <p>The <a class="reference internal" href="#module-wave" title="wave: Provide an interface to the WAV sound format."><tt class="xref py py-mod docutils literal"><span class="pre">wave</span></tt></a> module provides a convenient interface to the WAV sound format. It does not support compression/decompression, but it does support mono/stereo.</p> <p>The <a class="reference internal" href="#module-wave" title="wave: Provide an interface to the WAV sound format."><tt class="xref py py-mod docutils literal"><span class="pre">wave</span></tt></a> module defines the following function and exception:</p> <dl class="function"> <dt id="wave.open"> <tt class="descclassname">wave.</tt><tt class="descname">open</tt><big>(</big><em>file</em><span class="optional">[</span>, <em>mode</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#wave.open" title="Permalink to this definition">¶</a></dt> <dd><p>If <em>file</em> is a string, open the file by that name, otherwise treat it as a seekable file-like object. <em>mode</em> can be any of</p> <dl class="docutils"> <dt><tt class="docutils literal"><span class="pre">'r'</span></tt>, <tt class="docutils literal"><span class="pre">'rb'</span></tt></dt> <dd>Read only mode.</dd> <dt><tt class="docutils literal"><span class="pre">'w'</span></tt>, <tt class="docutils literal"><span class="pre">'wb'</span></tt></dt> <dd>Write only mode.</dd> </dl> <p>Note that it does not allow read/write WAV files.</p> <p>A <em>mode</em> of <tt class="docutils literal"><span class="pre">'r'</span></tt> or <tt class="docutils literal"><span class="pre">'rb'</span></tt> returns a <tt class="xref py py-class docutils literal"><span class="pre">Wave_read</span></tt> object, while a <em>mode</em> of <tt class="docutils literal"><span class="pre">'w'</span></tt> or <tt class="docutils literal"><span class="pre">'wb'</span></tt> returns a <tt class="xref py py-class docutils literal"><span class="pre">Wave_write</span></tt> object. If <em>mode</em> is omitted and a file-like object is passed as <em>file</em>, <tt class="docutils literal"><span class="pre">file.mode</span></tt> is used as the default value for <em>mode</em> (the <tt class="docutils literal"><span class="pre">'b'</span></tt> flag is still added if necessary).</p> <p>If you pass in a file-like object, the wave object will not close it when its <tt class="xref py py-meth docutils literal"><span class="pre">close()</span></tt> method is called; it is the caller’s responsibility to close the file object.</p> </dd></dl> <dl class="function"> <dt id="wave.openfp"> <tt class="descclassname">wave.</tt><tt class="descname">openfp</tt><big>(</big><em>file</em>, <em>mode</em><big>)</big><a class="headerlink" href="#wave.openfp" title="Permalink to this definition">¶</a></dt> <dd><p>A synonym for <a class="reference internal" href="#wave.open" title="wave.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a>, maintained for backwards compatibility.</p> </dd></dl> <dl class="exception"> <dt id="wave.Error"> <em class="property">exception </em><tt class="descclassname">wave.</tt><tt class="descname">Error</tt><a class="headerlink" href="#wave.Error" title="Permalink to this definition">¶</a></dt> <dd><p>An error raised when something is impossible because it violates the WAV specification or hits an implementation deficiency.</p> </dd></dl> <div class="section" id="wave-read-objects"> <span id="id1"></span><h2>21.5.1. Wave_read Objects<a class="headerlink" href="#wave-read-objects" title="Permalink to this headline">¶</a></h2> <p>Wave_read objects, as returned by <a class="reference internal" href="#wave.open" title="wave.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a>, have the following methods:</p> <dl class="method"> <dt id="wave.Wave_read.close"> <tt class="descclassname">Wave_read.</tt><tt class="descname">close</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.close" title="Permalink to this definition">¶</a></dt> <dd><p>Close the stream if it was opened by <a class="reference internal" href="#module-wave" title="wave: Provide an interface to the WAV sound format."><tt class="xref py py-mod docutils literal"><span class="pre">wave</span></tt></a>, and make the instance unusable. This is called automatically on object collection.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getnchannels"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getnchannels</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getnchannels" title="Permalink to this definition">¶</a></dt> <dd><p>Returns number of audio channels (<tt class="docutils literal"><span class="pre">1</span></tt> for mono, <tt class="docutils literal"><span class="pre">2</span></tt> for stereo).</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getsampwidth"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getsampwidth</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getsampwidth" title="Permalink to this definition">¶</a></dt> <dd><p>Returns sample width in bytes.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getframerate"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getframerate</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getframerate" title="Permalink to this definition">¶</a></dt> <dd><p>Returns sampling frequency.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getnframes"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getnframes</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getnframes" title="Permalink to this definition">¶</a></dt> <dd><p>Returns number of audio frames.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getcomptype"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getcomptype</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getcomptype" title="Permalink to this definition">¶</a></dt> <dd><p>Returns compression type (<tt class="docutils literal"><span class="pre">'NONE'</span></tt> is the only supported type).</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getcompname"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getcompname</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getcompname" title="Permalink to this definition">¶</a></dt> <dd><p>Human-readable version of <a class="reference internal" href="#wave.Wave_read.getcomptype" title="wave.Wave_read.getcomptype"><tt class="xref py py-meth docutils literal"><span class="pre">getcomptype()</span></tt></a>. Usually <tt class="docutils literal"><span class="pre">'not</span> <span class="pre">compressed'</span></tt> parallels <tt class="docutils literal"><span class="pre">'NONE'</span></tt>.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getparams"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getparams</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getparams" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a tuple <tt class="docutils literal"><span class="pre">(nchannels,</span> <span class="pre">sampwidth,</span> <span class="pre">framerate,</span> <span class="pre">nframes,</span> <span class="pre">comptype,</span> <span class="pre">compname)</span></tt>, equivalent to output of the <tt class="xref py py-meth docutils literal"><span class="pre">get*()</span></tt> methods.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.readframes"> <tt class="descclassname">Wave_read.</tt><tt class="descname">readframes</tt><big>(</big><em>n</em><big>)</big><a class="headerlink" href="#wave.Wave_read.readframes" title="Permalink to this definition">¶</a></dt> <dd><p>Reads and returns at most <em>n</em> frames of audio, as a string of bytes.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.rewind"> <tt class="descclassname">Wave_read.</tt><tt class="descname">rewind</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.rewind" title="Permalink to this definition">¶</a></dt> <dd><p>Rewind the file pointer to the beginning of the audio stream.</p> </dd></dl> <p>The following two methods are defined for compatibility with the <a class="reference internal" href="aifc.html#module-aifc" title="aifc: Read and write audio files in AIFF or AIFC format."><tt class="xref py py-mod docutils literal"><span class="pre">aifc</span></tt></a> module, and don’t do anything interesting.</p> <dl class="method"> <dt id="wave.Wave_read.getmarkers"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getmarkers</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.getmarkers" title="Permalink to this definition">¶</a></dt> <dd><p>Returns <tt class="docutils literal"><span class="pre">None</span></tt>.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.getmark"> <tt class="descclassname">Wave_read.</tt><tt class="descname">getmark</tt><big>(</big><em>id</em><big>)</big><a class="headerlink" href="#wave.Wave_read.getmark" title="Permalink to this definition">¶</a></dt> <dd><p>Raise an error.</p> </dd></dl> <p>The following two methods define a term “position” which is compatible between them, and is otherwise implementation dependent.</p> <dl class="method"> <dt id="wave.Wave_read.setpos"> <tt class="descclassname">Wave_read.</tt><tt class="descname">setpos</tt><big>(</big><em>pos</em><big>)</big><a class="headerlink" href="#wave.Wave_read.setpos" title="Permalink to this definition">¶</a></dt> <dd><p>Set the file pointer to the specified position.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_read.tell"> <tt class="descclassname">Wave_read.</tt><tt class="descname">tell</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_read.tell" title="Permalink to this definition">¶</a></dt> <dd><p>Return current file pointer position.</p> </dd></dl> </div> <div class="section" id="wave-write-objects"> <span id="id2"></span><h2>21.5.2. Wave_write Objects<a class="headerlink" href="#wave-write-objects" title="Permalink to this headline">¶</a></h2> <p>Wave_write objects, as returned by <a class="reference internal" href="#wave.open" title="wave.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a>, have the following methods:</p> <dl class="method"> <dt id="wave.Wave_write.close"> <tt class="descclassname">Wave_write.</tt><tt class="descname">close</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_write.close" title="Permalink to this definition">¶</a></dt> <dd><p>Make sure <em>nframes</em> is correct, and close the file if it was opened by <a class="reference internal" href="#module-wave" title="wave: Provide an interface to the WAV sound format."><tt class="xref py py-mod docutils literal"><span class="pre">wave</span></tt></a>. This method is called upon object collection.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setnchannels"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setnchannels</tt><big>(</big><em>n</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setnchannels" title="Permalink to this definition">¶</a></dt> <dd><p>Set the number of channels.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setsampwidth"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setsampwidth</tt><big>(</big><em>n</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setsampwidth" title="Permalink to this definition">¶</a></dt> <dd><p>Set the sample width to <em>n</em> bytes.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setframerate"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setframerate</tt><big>(</big><em>n</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setframerate" title="Permalink to this definition">¶</a></dt> <dd><p>Set the frame rate to <em>n</em>.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setnframes"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setnframes</tt><big>(</big><em>n</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setnframes" title="Permalink to this definition">¶</a></dt> <dd><p>Set the number of frames to <em>n</em>. This will be changed later if more frames are written.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setcomptype"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setcomptype</tt><big>(</big><em>type</em>, <em>name</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setcomptype" title="Permalink to this definition">¶</a></dt> <dd><p>Set the compression type and description. At the moment, only compression type <tt class="docutils literal"><span class="pre">NONE</span></tt> is supported, meaning no compression.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.setparams"> <tt class="descclassname">Wave_write.</tt><tt class="descname">setparams</tt><big>(</big><em>tuple</em><big>)</big><a class="headerlink" href="#wave.Wave_write.setparams" title="Permalink to this definition">¶</a></dt> <dd><p>The <em>tuple</em> should be <tt class="docutils literal"><span class="pre">(nchannels,</span> <span class="pre">sampwidth,</span> <span class="pre">framerate,</span> <span class="pre">nframes,</span> <span class="pre">comptype,</span> <span class="pre">compname)</span></tt>, with values valid for the <tt class="xref py py-meth docutils literal"><span class="pre">set*()</span></tt> methods. Sets all parameters.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.tell"> <tt class="descclassname">Wave_write.</tt><tt class="descname">tell</tt><big>(</big><big>)</big><a class="headerlink" href="#wave.Wave_write.tell" title="Permalink to this definition">¶</a></dt> <dd><p>Return current position in the file, with the same disclaimer for the <a class="reference internal" href="#wave.Wave_read.tell" title="wave.Wave_read.tell"><tt class="xref py py-meth docutils literal"><span class="pre">Wave_read.tell()</span></tt></a> and <a class="reference internal" href="#wave.Wave_read.setpos" title="wave.Wave_read.setpos"><tt class="xref py py-meth docutils literal"><span class="pre">Wave_read.setpos()</span></tt></a> methods.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.writeframesraw"> <tt class="descclassname">Wave_write.</tt><tt class="descname">writeframesraw</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#wave.Wave_write.writeframesraw" title="Permalink to this definition">¶</a></dt> <dd><p>Write audio frames, without correcting <em>nframes</em>.</p> </dd></dl> <dl class="method"> <dt id="wave.Wave_write.writeframes"> <tt class="descclassname">Wave_write.</tt><tt class="descname">writeframes</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#wave.Wave_write.writeframes" title="Permalink to this definition">¶</a></dt> <dd><p>Write audio frames and make sure <em>nframes</em> is correct.</p> </dd></dl> <p>Note that it is invalid to set any parameters after calling <tt class="xref py py-meth docutils literal"><span class="pre">writeframes()</span></tt> or <tt class="xref py py-meth docutils literal"><span class="pre">writeframesraw()</span></tt>, and any attempt to do so will raise <a class="reference internal" href="#wave.Error" title="wave.Error"><tt class="xref py py-exc docutils literal"><span class="pre">wave.Error</span></tt></a>.</p> </div> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">21.5. <tt class="docutils literal"><span class="pre">wave</span></tt> — Read and write WAV files</a><ul> <li><a class="reference internal" href="#wave-read-objects">21.5.1. Wave_read Objects</a></li> <li><a class="reference internal" href="#wave-write-objects">21.5.2. Wave_write Objects</a></li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="sunau.html" title="previous chapter">21.4. <tt class="docutils literal"><span class="pre">sunau</span></tt> — Read and write Sun AU files</a></p> <h4>Next topic</h4> <p class="topless"><a href="chunk.html" title="next chapter">21.6. <tt class="docutils literal"><span class="pre">chunk</span></tt> — Read IFF chunked data</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/library/wave.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="chunk.html" title="21.6. chunk — Read IFF chunked data" >next</a> |</li> <li class="right" > <a href="sunau.html" title="21.4. sunau — Read and write Sun AU files" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="mm.html" >21. 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