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| <a href="#gst-plugins-base-libs-gststreamvolume.synopsis" class="shortcut">Top</a> |
| | |
| <a href="#gst-plugins-base-libs-gststreamvolume.description" class="shortcut">Description</a> |
| | |
| <a href="#gst-plugins-base-libs-gststreamvolume.object-hierarchy" class="shortcut">Object Hierarchy</a> |
| | |
| <a href="#gst-plugins-base-libs-gststreamvolume.prerequisites" class="shortcut">Prerequisites</a> |
| | |
| <a href="#gst-plugins-base-libs-gststreamvolume.properties" class="shortcut">Properties</a> |
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| <div class="refentry"> |
| <a name="gst-plugins-base-libs-gststreamvolume"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="gst-plugins-base-libs-gststreamvolume.top_of_page"></a>gststreamvolume</span></h2> |
| <p>gststreamvolume — Interface for elements that provide a stream volume</p> |
| </td> |
| <td valign="top" align="right"></td> |
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| <div class="refsynopsisdiv"> |
| <a name="gst-plugins-base-libs-gststreamvolume.synopsis"></a><h2>Synopsis</h2> |
| <a name="GstStreamVolume"></a><pre class="synopsis"> |
| #include <gst/audio/streamvolume.h> |
| |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume-struct" title="GstStreamVolume">GstStreamVolume</a>; |
| enum <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat">GstStreamVolumeFormat</a>; |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="returnvalue">gdouble</span></a> <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-get-volume" title="gst_stream_volume_get_volume ()">gst_stream_volume_get_volume</a> (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> format</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-set-volume" title="gst_stream_volume_set_volume ()">gst_stream_volume_set_volume</a> (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> format</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> val</code></em>); |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-get-mute" title="gst_stream_volume_get_mute ()">gst_stream_volume_get_mute</a> (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>); |
| <span class="returnvalue">void</span> <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-set-mute" title="gst_stream_volume_set_mute ()">gst_stream_volume_set_mute</a> (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> mute</code></em>); |
| <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="returnvalue">gdouble</span></a> <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-convert-volume" title="gst_stream_volume_convert_volume ()">gst_stream_volume_convert_volume</a> (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> from</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> to</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> val</code></em>); |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="synopsis"> |
| GInterface |
| +----GstStreamVolume |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.prerequisites"></a><h2>Prerequisites</h2> |
| <p> |
| GstStreamVolume requires |
| <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>.</p> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.properties"></a><h2>Properties</h2> |
| <pre class="synopsis"> |
| "<a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume--mute" title='The "mute" property'>mute</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write |
| "<a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume--volume" title='The "volume" property'>volume</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.description"></a><h2>Description</h2> |
| <p> |
| </p> |
| <div class="refsect2"> |
| <a name="id-1.2.6.18.7.2.1"></a><p> |
| This interface is implemented by elements that provide a stream volume. Examples for |
| such elements are <span class="type">volume</span> and <span class="type">playbin</span>. |
| </p> |
| <p> |
| Applications can use this interface to get or set the current stream volume. For this |
| the "volume" <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a> property can be used or the helper functions <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-set-volume" title="gst_stream_volume_set_volume ()"><code class="function">gst_stream_volume_set_volume()</code></a> |
| and <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-get-volume" title="gst_stream_volume_get_volume ()"><code class="function">gst_stream_volume_get_volume()</code></a>. This volume is always a linear factor, i.e. 0.0 is muted |
| 1.0 is 100%. For showing the volume in a GUI it might make sense to convert it to |
| a different format by using <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-convert-volume" title="gst_stream_volume_convert_volume ()"><code class="function">gst_stream_volume_convert_volume()</code></a>. Volume sliders should usually |
| use a cubic volume. |
| </p> |
| <p> |
| Separate from the volume the stream can also be muted by the "mute" <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a> property or |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-set-mute" title="gst_stream_volume_set_mute ()"><code class="function">gst_stream_volume_set_mute()</code></a> and <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-get-mute" title="gst_stream_volume_get_mute ()"><code class="function">gst_stream_volume_get_mute()</code></a>. |
| </p> |
| <p> |
| Elements that provide some kind of stream volume should implement the "volume" and |
| "mute" <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a> properties and handle setting and getting of them properly. |
| The volume property is defined to be a linear volume factor. |
| </p> |
| </div> |
| <p> |
| </p> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.details"></a><h2>Details</h2> |
| <div class="refsect2"> |
| <a name="GstStreamVolume-struct"></a><h3>GstStreamVolume</h3> |
| <pre class="programlisting">typedef struct _GstStreamVolume GstStreamVolume;</pre> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstStreamVolumeFormat"></a><h3>enum GstStreamVolumeFormat</h3> |
| <pre class="programlisting">typedef enum { |
| GST_STREAM_VOLUME_FORMAT_LINEAR = 0, |
| GST_STREAM_VOLUME_FORMAT_CUBIC, |
| GST_STREAM_VOLUME_FORMAT_DB |
| } GstStreamVolumeFormat; |
| </pre> |
| <p> |
| Different representations of a stream volume. <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#gst-stream-volume-convert-volume" title="gst_stream_volume_convert_volume ()"><code class="function">gst_stream_volume_convert_volume()</code></a> |
| allows to convert between the different representations. |
| </p> |
| <p> |
| Formulas to convert from a linear to a cubic or dB volume are |
| cbrt(val) and 20 * log10 (val). |
| </p> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><a name="GST-STREAM-VOLUME-FORMAT-LINEAR:CAPS"></a><span class="term"><code class="literal">GST_STREAM_VOLUME_FORMAT_LINEAR</code></span></p></td> |
| <td>Linear scale factor, 1.0 = 100% |
| </td> |
| </tr> |
| <tr> |
| <td><p><a name="GST-STREAM-VOLUME-FORMAT-CUBIC:CAPS"></a><span class="term"><code class="literal">GST_STREAM_VOLUME_FORMAT_CUBIC</code></span></p></td> |
| <td>Cubic volume scale |
| </td> |
| </tr> |
| <tr> |
| <td><p><a name="GST-STREAM-VOLUME-FORMAT-DB:CAPS"></a><span class="term"><code class="literal">GST_STREAM_VOLUME_FORMAT_DB</code></span></p></td> |
| <td>Logarithmic volume scale (dB, amplitude not power) |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-stream-volume-get-volume"></a><h3>gst_stream_volume_get_volume ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="returnvalue">gdouble</span></a> gst_stream_volume_get_volume (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> format</code></em>);</pre> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>volume</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> that should be used</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>format</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> which should be returned</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>The current stream volume as linear factor</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-stream-volume-set-volume"></a><h3>gst_stream_volume_set_volume ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_stream_volume_set_volume (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> format</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> val</code></em>);</pre> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>volume</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> that should be used</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>format</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> of <em class="parameter"><code>val</code></em> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>val</code></em> :</span></p></td> |
| <td>Linear volume factor that should be set</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-stream-volume-get-mute"></a><h3>gst_stream_volume_get_mute ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_stream_volume_get_mute (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>);</pre> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>volume</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> that should be used</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>Returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the stream is muted</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-stream-volume-set-mute"></a><h3>gst_stream_volume_set_mute ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> gst_stream_volume_set_mute (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> *volume</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> mute</code></em>);</pre> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>volume</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolume"><span class="type">GstStreamVolume</span></a> that should be used</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>mute</code></em> :</span></p></td> |
| <td>Mute state that should be set</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-stream-volume-convert-volume"></a><h3>gst_stream_volume_convert_volume ()</h3> |
| <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="returnvalue">gdouble</span></a> gst_stream_volume_convert_volume (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> from</code></em>, |
| <em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> to</code></em>, |
| <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> val</code></em>);</pre> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>from</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> to convert from</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>to</code></em> :</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-base-libs-gststreamvolume.html#GstStreamVolumeFormat" title="enum GstStreamVolumeFormat"><span class="type">GstStreamVolumeFormat</span></a> to convert to</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>val</code></em> :</span></p></td> |
| <td>Volume in <em class="parameter"><code>from</code></em> format that should be converted</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td>the converted volume</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-base-libs-gststreamvolume.property-details"></a><h2>Property Details</h2> |
| <div class="refsect2"> |
| <a name="GstStreamVolume--mute"></a><h3>The <code class="literal">"mute"</code> property</h3> |
| <pre class="programlisting"> "mute" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre> |
| <p>Mute the audio channel without changing the volume.</p> |
| <p>Default value: FALSE</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstStreamVolume--volume"></a><h3>The <code class="literal">"volume"</code> property</h3> |
| <pre class="programlisting"> "volume" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write</pre> |
| <p>Linear volume factor, 1.0=100%.</p> |
| <p>Allowed values: >= 0</p> |
| <p>Default value: 1</p> |
| </div> |
| </div> |
| </div> |
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