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<a href="#gst-plugins-bad-plugins-scaletempo.properties" class="shortcut">Properties</a>
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<div class="refentry" title="scaletempo">
<a name="gst-plugins-bad-plugins-scaletempo"></a><div class="titlepage"></div>
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<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>
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<div class="refsynopsisdiv" title="Synopsis">
<a name="gst-plugins-bad-plugins-scaletempo.synopsis"></a><h2>Synopsis</h2>
<a name="GstScaletempo"></a><pre class="synopsis"> <a class="link" href="gst-plugins-bad-plugins-scaletempo.html#GstScaletempo-struct" title="GstScaletempo">GstScaletempo</a>;
</pre>
</div>
<div class="refsect1" title="Object Hierarchy">
<a name="gst-plugins-bad-plugins-scaletempo.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="synopsis">
<a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a>
+----<a href="/usr/share/gtk-doc/html/gstreamer-0.10/GstObject.html">GstObject</a>
+----<a href="/usr/share/gtk-doc/html/gstreamer-0.10/GstElement.html">GstElement</a>
+----<a href="/usr/share/gtk-doc/html/gstreamer-libs-0.10/GstBaseTransform.html">GstBaseTransform</a>
+----GstScaletempo
</pre>
</div>
<div class="refsect1" title="Properties">
<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="/usr/share/gtk-doc/html/glib/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="/usr/share/gtk-doc/html/glib/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="/usr/share/gtk-doc/html/glib/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="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write
</pre>
</div>
<div class="refsect1" title="Description">
<a name="gst-plugins-bad-plugins-scaletempo.description"></a><h2>Description</h2>
<p>
</p>
<div class="refsect2" title="Example pipelines">
<a name="id408314"></a><h3>Example pipelines</h3>
<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>
<pre class="programlisting">
filesrc location=media.ext ! decodebin name=d \
d. ! queue ! audioconvert ! audioresample ! scaletempo ! audioconvert ! audioresample ! autoaudiosink \
d. ! queue ! ffmpegcolorspace ! autovideosink
</pre>
<p>
OR
</p>
<pre class="programlisting">
playbin uri=... audio_sink="scaletempo ! audioconvert ! audioresample ! autoaudiosink"
</pre>
<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 "stride") 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 ("overlap").
</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.
</p>
</div>
</div>
<div class="refsect1" title="Details">
<a name="gst-plugins-bad-plugins-scaletempo.details"></a><h2>Details</h2>
<div class="refsect2" title="GstScaletempo">
<a name="GstScaletempo-struct"></a><h3>GstScaletempo</h3>
<pre class="programlisting">typedef struct _GstScaletempo GstScaletempo;</pre>
<p>
</p>
</div>
</div>
<div class="refsect1" title="Property Details">
<a name="gst-plugins-bad-plugins-scaletempo.property-details"></a><h2>Property Details</h2>
<div class="refsect2" title='The "overlap" property'>
<a name="GstScaletempo--overlap"></a><h3>The <code class="literal">"overlap"</code> property</h3>
<pre class="programlisting"> "overlap" <a href="/usr/share/gtk-doc/html/glib/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" title='The "rate" property'>
<a name="GstScaletempo--rate"></a><h3>The <code class="literal">"rate"</code> property</h3>
<pre class="programlisting"> "rate" <a href="/usr/share/gtk-doc/html/glib/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" title='The "search" property'>
<a name="GstScaletempo--search"></a><h3>The <code class="literal">"search"</code> property</h3>
<pre class="programlisting"> "search" <a href="/usr/share/gtk-doc/html/glib/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" title='The "stride" property'>
<a name="GstScaletempo--stride"></a><h3>The <code class="literal">"stride"</code> property</h3>
<pre class="programlisting"> "stride" <a href="/usr/share/gtk-doc/html/glib/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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