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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<a href="#gst-plugins-bad-plugins-scaletempo.synopsis" class="shortcut">Top</a>
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<a href="#gst-plugins-bad-plugins-scaletempo.description" class="shortcut">Description</a>
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<a href="#gst-plugins-bad-plugins-scaletempo.object-hierarchy" class="shortcut">Object Hierarchy</a>
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<a href="#gst-plugins-bad-plugins-scaletempo.properties" class="shortcut">Properties</a>
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<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://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</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="idp13904560"></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> videoconvert <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="idp16747536"></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="idp17780912"></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, format=(string)F32LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)S16LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</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, format=(string)F32LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)S16LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</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>
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