<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>scaletempo</title> <meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> <link rel="home" href="index.html" title="GStreamer Bad Plugins 0.10 Plugins Reference Manual"> <link rel="up" href="ch01.html" title="gst-plugins-bad Elements"> <link rel="prev" href="gst-plugins-bad-plugins-rtpmux.html" title="rtpmux"> <link rel="next" href="gst-plugins-bad-plugins-sdlaudiosink.html" title="sdlaudiosink"> <meta name="generator" content="GTK-Doc V1.18 (XML mode)"> <link rel="stylesheet" href="style.css" type="text/css"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"> <tr valign="middle"> <td><a accesskey="p" href="gst-plugins-bad-plugins-rtpmux.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td> <td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td> <td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td> <th width="100%" align="center">GStreamer Bad Plugins 0.10 Plugins Reference Manual</th> <td><a accesskey="n" href="gst-plugins-bad-plugins-sdlaudiosink.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td> </tr> <tr><td colspan="5" class="shortcuts"> <a href="#gst-plugins-bad-plugins-scaletempo.synopsis" class="shortcut">Top</a> | <a href="#gst-plugins-bad-plugins-scaletempo.description" class="shortcut">Description</a> | <a href="#gst-plugins-bad-plugins-scaletempo.object-hierarchy" class="shortcut">Object Hierarchy</a> | <a href="#gst-plugins-bad-plugins-scaletempo.properties" class="shortcut">Properties</a> </td></tr> </table> <div class="refentry"> <a name="gst-plugins-bad-plugins-scaletempo"></a><div class="titlepage"></div> <div class="refnamediv"><table width="100%"><tr> <td valign="top"> <h2><span class="refentrytitle"><a name="gst-plugins-bad-plugins-scaletempo.top_of_page"></a>scaletempo</span></h2> <p>scaletempo — Sync audio tempo with playback rate</p> </td> <td valign="top" align="right"></td> </tr></table></div> <div class="refsynopsisdiv"> <a name="gst-plugins-bad-plugins-scaletempo.synopsis"></a><h2>Synopsis</h2> <a name="GstScaletempo"></a><pre class="synopsis">struct <a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo-struct" title="struct GstScaletempo">GstScaletempo</a>; </pre> </div> <div class="refsect1"> <a name="gst-plugins-bad-plugins-scaletempo.object-hierarchy"></a><h2>Object Hierarchy</h2> <pre class="synopsis"> <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a> +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a> +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a> +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseTransform.html">GstBaseTransform</a> +----GstScaletempo </pre> </div> <div class="refsect1"> <a name="gst-plugins-bad-plugins-scaletempo.properties"></a><h2>Properties</h2> <pre class="synopsis"> "<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--overlap" title='The "overlap" property'>overlap</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write "<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--rate" title='The "rate" property'>rate</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read "<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--search" title='The "search" property'>search</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write "<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--stride" title='The "stride" property'>stride</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write </pre> </div> <div class="refsect1"> <a name="gst-plugins-bad-plugins-scaletempo.description"></a><h2>Description</h2> <p> Scale tempo while maintaining pitch (WSOLA-like technique with cross correlation) Inspired by SoundTouch library by Olli Parviainen </p> <p> Use Sceletempo to apply playback rates without the chipmunk effect. </p> <p> </p> <div class="refsect2"> <a name="idp19579248"></a><h3>Example pipelines</h3> <p> </p> <div class="informalexample"> <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td class="listing_lines" align="right"><pre>1 2 3</pre></td> <td class="listing_code"><pre class="programlisting">filesrc location<span class="gtkdoc opt">=</span>media<span class="gtkdoc opt">.</span>ext <span class="gtkdoc opt">!</span> decodebin name<span class="gtkdoc opt">=</span>d \ d<span class="gtkdoc opt">. !</span> queue <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audioresample <span class="gtkdoc opt">!</span> scaletempo <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audioresample <span class="gtkdoc opt">!</span> autoaudiosink \ d<span class="gtkdoc opt">. !</span> queue <span class="gtkdoc opt">!</span> ffmpegcolorspace <span class="gtkdoc opt">!</span> autovideosink</pre></td> </tr> </tbody> </table> </div> <p> OR </p> <div class="informalexample"> <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> <tbody> <tr> <td class="listing_lines" align="right"><pre>1</pre></td> <td class="listing_code"><pre class="programlisting">playbin uri<span class="gtkdoc opt">=...</span> audio_sink<span class="gtkdoc opt">=</span><span class="string">"scaletempo ! audioconvert ! audioresample ! autoaudiosink"</span></pre></td> </tr> </tbody> </table> </div> <p> When an application sends a seek event with rate != 1.0, Scaletempo applies the rate change by scaling the tempo without scaling the pitch. </p> <p> Scaletempo works by producing audio in constant sized chunks (<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--stride" title='The "stride" property'><span class="type">"stride"</span></a>) but consuming chunks proportional to the playback rate. </p> <p> Scaletempo then smooths the output by blending the end of one stride with the next (<a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--overlap" title='The "overlap" property'><span class="type">"overlap"</span></a>). </p> <p> Scaletempo smooths the overlap further by searching within the input buffer for the best overlap position. Scaletempo uses a statistical cross correlation (roughly a dot-product). Scaletempo consumes most of its CPU cycles here. One can use the <a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo--search" title='The "search" property'><span class="type">"search"</span></a> propery to tune how far the algoritm looks. </p> </div> <p> </p> <div class="refsynopsisdiv"> <h2>Synopsis</h2> <div class="refsect2"> <a name="idp21493200"></a><h3>Element Information</h3> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term">plugin</span></p></td> <td> <a class="link" href="gst-plugins-bad-plugins-plugin-scaletempo.html#plugin-scaletempo">scaletempo</a> </td> </tr> <tr> <td><p><span class="term">author</span></p></td> <td>Rov Juvano <rovjuvano@users.sourceforge.net></td> </tr> <tr> <td><p><span class="term">class</span></p></td> <td>Filter/Effect/Rate</td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2"> <a name="idp18294848"></a><h3>Element Pads</h3> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term">name</span></p></td> <td>sink</td> </tr> <tr> <td><p><span class="term">direction</span></p></td> <td>sink</td> </tr> <tr> <td><p><span class="term">presence</span></p></td> <td>always</td> </tr> <tr> <td><p><span class="term">details</span></p></td> <td>audio/x-raw-float, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int)32</td> </tr> <tr> <td><p><span class="term"></span></p></td> <td> audio/x-raw-int, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int)16, depth=(int)16, signed=(boolean)true</td> </tr> </tbody> </table></div> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term">name</span></p></td> <td>src</td> </tr> <tr> <td><p><span class="term">direction</span></p></td> <td>source</td> </tr> <tr> <td><p><span class="term">presence</span></p></td> <td>always</td> </tr> <tr> <td><p><span class="term">details</span></p></td> <td>audio/x-raw-float, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int)32</td> </tr> <tr> <td><p><span class="term"></span></p></td> <td> audio/x-raw-int, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int)16, depth=(int)16, signed=(boolean)true</td> </tr> </tbody> </table></div> </div> </div> <p> </p> </div> <div class="refsect1"> <a name="gst-plugins-bad-plugins-scaletempo.details"></a><h2>Details</h2> <div class="refsect2"> <a name="GstScaletempo-struct"></a><h3>struct GstScaletempo</h3> <pre class="programlisting">struct GstScaletempo;</pre> <p> </p> </div> </div> <div class="refsect1"> <a name="gst-plugins-bad-plugins-scaletempo.property-details"></a><h2>Property Details</h2> <div class="refsect2"> <a name="GstScaletempo--overlap"></a><h3>The <code class="literal">"overlap"</code> property</h3> <pre class="programlisting"> "overlap" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write</pre> <p>Percentage of stride to overlap.</p> <p>Allowed values: [0,1]</p> <p>Default value: 0.2</p> </div> <hr> <div class="refsect2"> <a name="GstScaletempo--rate"></a><h3>The <code class="literal">"rate"</code> property</h3> <pre class="programlisting"> "rate" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read</pre> <p>Current playback rate.</p> <p>Allowed values: [-2.14748e+09,2.14748e+09]</p> <p>Default value: 1</p> </div> <hr> <div class="refsect2"> <a name="GstScaletempo--search"></a><h3>The <code class="literal">"search"</code> property</h3> <pre class="programlisting"> "search" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre> <p>Length in milliseconds to search for best overlap position.</p> <p>Allowed values: <= 500</p> <p>Default value: 14</p> </div> <hr> <div class="refsect2"> <a name="GstScaletempo--stride"></a><h3>The <code class="literal">"stride"</code> property</h3> <pre class="programlisting"> "stride" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre> <p>Length in milliseconds to output each stride.</p> <p>Allowed values: [1,5000]</p> <p>Default value: 30</p> </div> </div> </div> <div class="footer"> <hr> Generated by GTK-Doc V1.18</div> </body> </html>