1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>audioconvert: GStreamer Base Plugins 1.0 Plugins Reference Manual</title> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="index.html" title="GStreamer Base Plugins 1.0 Plugins Reference Manual"> 8<link rel="up" href="ch01.html" title="gst-plugins-base Elements"> 9<link rel="prev" href="gst-plugins-base-plugins-appsrc.html" title="appsrc"> 10<link rel="next" href="gst-plugins-base-plugins-audiointerleave.html" title="audiointerleave"> 11<meta name="generator" content="GTK-Doc V1.28 (XML mode)"> 12<link rel="stylesheet" href="style.css" type="text/css"> 13</head> 14<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 15<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="5"><tr valign="middle"> 16<td 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href="gst-plugins-base-plugins-audiointerleave.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td> 26</tr></table> 27<div class="refentry"> 28<a name="gst-plugins-base-plugins-audioconvert"></a><div class="titlepage"></div> 29<div class="refnamediv"><table width="100%"><tr> 30<td valign="top"> 31<h2><span class="refentrytitle"><a name="gst-plugins-base-plugins-audioconvert.top_of_page"></a>audioconvert</span></h2> 32<p>audioconvert</p> 33</td> 34<td class="gallery_image" valign="top" align="right"></td> 35</tr></table></div> 36<div class="refsect1"> 37<a name="gst-plugins-base-plugins-audioconvert.properties"></a><h2>Properties</h2> 38<div class="informaltable"><table class="informaltable" border="0"> 39<colgroup> 40<col width="150px" class="properties_type"> 41<col width="300px" class="properties_name"> 42<col width="200px" class="properties_flags"> 43</colgroup> 44<tbody> 45<tr> 46<td class="property_type"><a href="../html/gst-plugins-base-libs-GstAudioQuantize.html#GstAudioDitherMethod"><span class="type">GstAudioDitherMethod</span></a></td> 47<td class="property_name"><a class="link" href="gst-plugins-base-plugins-audioconvert.html#GstAudioConvert--dithering" title="The “dithering” property">dithering</a></td> 48<td class="property_flags">Read / Write</td> 49</tr> 50<tr> 51<td class="property_type"><a href="../html/gst-plugins-base-libs-GstAudioQuantize.html#GstAudioNoiseShapingMethod"><span class="type">GstAudioNoiseShapingMethod</span></a></td> 52<td class="property_name"><a class="link" href="gst-plugins-base-plugins-audioconvert.html#GstAudioConvert--noise-shaping" title="The “noise-shaping” property">noise-shaping</a></td> 53<td class="property_flags">Read / Write</td> 54</tr> 55<tr> 56<td class="property_type"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstControlSource.html#GstValueArray"><span class="type">GstValueArray</span></a></td> 57<td class="property_name"><a class="link" href="gst-plugins-base-plugins-audioconvert.html#GstAudioConvert--mix-matrix" title="The “mix-matrix” property">mix-matrix</a></td> 58<td class="property_flags">Read / Write</td> 59</tr> 60</tbody> 61</table></div> 62</div> 63<a name="GstAudioConvert"></a><div class="refsect1"> 64<a name="gst-plugins-base-plugins-audioconvert.other"></a><h2>Types and Values</h2> 65<div class="informaltable"><table class="informaltable" width="100%" border="0"> 66<colgroup> 67<col width="150px" class="name"> 68<col class="description"> 69</colgroup> 70<tbody><tr> 71<td class="datatype_keyword">struct</td> 72<td class="function_name"><a class="link" href="gst-plugins-base-plugins-audioconvert.html#GstAudioConvert-struct" title="struct GstAudioConvert">GstAudioConvert</a></td> 73</tr></tbody> 74</table></div> 75</div> 76<div class="refsect1"> 77<a name="gst-plugins-base-plugins-audioconvert.object-hierarchy"></a><h2>Object Hierarchy</h2> 78<pre class="screen"> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a> 79 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a> 80 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#GstObject-struct">GstObject</a> 81 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#GstElement-struct">GstElement</a> 82 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-libs-1.0/GstBaseTransform.html#GstBaseTransform-struct">GstBaseTransform</a> 83 <span class="lineart">╰──</span> GstAudioConvert 84</pre> 85</div> 86<div class="refsect1"> 87<a name="gst-plugins-base-plugins-audioconvert.description"></a><h2>Description</h2> 88<p>Audioconvert converts raw audio buffers between various possible formats. 89It supports integer to float conversion, width/depth conversion, 90signedness and endianness conversion and channel transformations 91(ie. upmixing and downmixing), as well as dithering and noise-shaping.</p> 92<div class="refsect3"> 93<a name="id-1.2.8.7.3"></a><h4>Example launch line</h4> 94<div class="informalexample"> 95 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 96 <tbody> 97 <tr> 98 <td class="listing_lines" align="right"><pre>1</pre></td> 99 <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch<span class="gtkdoc opt">-</span><span class="number">1.0</span> <span class="gtkdoc opt">-</span>v <span class="gtkdoc opt">-</span>m audiotestsrc <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audio<span class="gtkdoc opt">/</span>x<span class="gtkdoc opt">-</span>raw<span class="gtkdoc opt">,</span>format<span class="gtkdoc opt">=</span>S8<span class="gtkdoc opt">,</span>channels<span class="gtkdoc opt">=</span><span class="number">2</span> <span class="gtkdoc opt">!</span> level <span class="gtkdoc opt">!</span> fakesink silent<span class="gtkdoc opt">=</span>TRUE</pre></td> 100 </tr> 101 </tbody> 102 </table> 103</div> 104 105<p> 106 This pipeline converts audio to 8-bit. The level element shows that 107the output levels still match the one for a sine wave.</p> 108<div class="informalexample"> 109 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 110 <tbody> 111 <tr> 112 <td class="listing_lines" align="right"><pre>1</pre></td> 113 <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch<span class="gtkdoc opt">-</span><span class="number">1.0</span> <span class="gtkdoc opt">-</span>v <span class="gtkdoc opt">-</span>m uridecodebin uri<span class="gtkdoc opt">=</span>file<span class="gtkdoc opt">:</span><span class="gtkdoc slc">///path/to/audio.flac ! audioconvert ! vorbisenc ! oggmux ! filesink location=audio.ogg</span></pre></td> 114 </tr> 115 </tbody> 116 </table> 117</div> 118 119<p> 120 The vorbis encoder takes float audio data instead of the integer data 121output by most other audio elements. This pipeline decodes a FLAC audio file 122(or any other audio file for which decoders are installed) and re-encodes 123it into an Ogg/Vorbis audio file.</p> 124<p>A mix matrix can be passed to audioconvert, that will govern the 125remapping of input to output channels.</p> 126</div> 127<div class="refsect3"> 128<a name="id-1.2.8.7.4"></a><h4>Example matrix generation code</h4> 129<p>To generate the matrix using code:</p> 130<div class="informalexample"> 131 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 132 <tbody> 133 <tr> 134 <td class="listing_lines" align="right"><pre>1 1352 1363 1374 1385 1396 1407 1418 1429 14310 14411 14512 14613 14714 14815 14916</pre></td> 150 <td class="listing_code"><pre class="programlisting">GValue v <span class="gtkdoc opt">=</span> G_VALUE_INIT<span class="gtkdoc opt">;</span> 151GValue v2 <span class="gtkdoc opt">=</span> G_VALUE_INIT<span class="gtkdoc opt">;</span> 152GValue v3 <span class="gtkdoc opt">=</span> G_VALUE_INIT<span class="gtkdoc opt">;</span> 153 154<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-init">g_value_init</a></span> <span class="gtkdoc opt">(&</span>v2<span class="gtkdoc opt">,</span> GST_TYPE_ARRAY<span class="gtkdoc opt">);</span> 155<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-init">g_value_init</a></span> <span class="gtkdoc opt">(&</span>v3<span class="gtkdoc opt">,</span> G_TYPE_FLOAT<span class="gtkdoc opt">);</span> 156<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-set-float">g_value_set_float</a></span> <span class="gtkdoc opt">(&</span>v3<span class="gtkdoc opt">,</span> <span class="number">1</span><span class="gtkdoc opt">);</span> 157<span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-GstValue.html#gst-value-array-append-value">gst_value_array_append_value</a></span> <span class="gtkdoc opt">(&</span>v2<span class="gtkdoc opt">, &</span>v3<span class="gtkdoc opt">);</span> 158<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-unset">g_value_unset</a></span> <span class="gtkdoc opt">(&</span>v3<span class="gtkdoc opt">);</span> 159<span class="gtkdoc opt">[</span> Repeat <span class="keyword">for</span> as many <span class="gtkdoc kwb">float</span> as your input channels <span class="gtkdoc opt">-</span> unset <span class="keyword">and</span> reinit v3 <span class="gtkdoc opt">]</span> 160<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-init">g_value_init</a></span> <span class="gtkdoc opt">(&</span>v<span class="gtkdoc opt">,</span> GST_TYPE_ARRAY<span class="gtkdoc opt">);</span> 161<span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-GstValue.html#gst-value-array-append-value">gst_value_array_append_value</a></span> <span class="gtkdoc opt">(&</span>v<span class="gtkdoc opt">, &</span>v2<span class="gtkdoc opt">);</span> 162<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-unset">g_value_unset</a></span> <span class="gtkdoc opt">(&</span>v2<span class="gtkdoc opt">);</span> 163<span class="gtkdoc opt">[</span> Repeat <span class="keyword">for</span> as many v2<span class="string">'s as your output channels - unset and reinit v2]</span> 164<span class="string">g_object_set_property (G_OBJECT (audioconvert), "mix-matrix", &v);</span> 165<span class="string">g_value_unset (&v);</span></pre></td> 166 </tr> 167 </tbody> 168 </table> 169</div> 170 171<p></p> 172</div> 173<div class="refsect3"> 174<a name="id-1.2.8.7.5"></a><h4>Example launch line</h4> 175<div class="informalexample"> 176 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 177 <tbody> 178 <tr> 179 <td class="listing_lines" align="right"><pre>1</pre></td> 180 <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch<span class="gtkdoc opt">-</span><span class="number">1.0</span> audiotestsrc <span class="gtkdoc opt">!</span> audio<span class="gtkdoc opt">/</span>x<span class="gtkdoc opt">-</span>raw<span class="gtkdoc opt">,</span> channels<span class="gtkdoc opt">=</span><span class="number">4</span> <span class="gtkdoc opt">!</span> audioconvert mix<span class="gtkdoc opt">-</span>matrix<span class="gtkdoc opt">=</span><span class="string">"<<(float)1.0, (float)0.0, (float)0.0, (float)0.0>, <(float)0.0, (float)1.0, (float)0.0, (float)0.0>>"</span> <span class="gtkdoc opt">!</span> audio<span class="gtkdoc opt">/</span>x<span class="gtkdoc opt">-</span>raw<span class="gtkdoc opt">,</span>channels<span class="gtkdoc opt">=</span><span class="number">2</span> <span class="gtkdoc opt">!</span> autoaudiosink</pre></td> 181 </tr> 182 </tbody> 183 </table> 184</div> 185 186<p></p> 187<div class="blockquote"><blockquote class="blockquote"><p>If an empty mix matrix is specified, a (potentially truncated) 188identity matrix will be generated.</p></blockquote></div> 189</div> 190<div class="refsect3"> 191<a name="id-1.2.8.7.6"></a><h4>Example empty matrix generation code</h4> 192<div class="informalexample"> 193 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 194 <tbody> 195 <tr> 196 <td class="listing_lines" align="right"><pre>1 1972 1983 1994 2005</pre></td> 201 <td class="listing_code"><pre class="programlisting">GValue v <span class="gtkdoc opt">=</span> G_VALUE_INIT<span class="gtkdoc opt">;</span> 202 203<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-init">g_value_init</a></span> <span class="gtkdoc opt">(&</span>v<span class="gtkdoc opt">,</span> GST_TYPE_ARRAY<span class="gtkdoc opt">);</span> 204<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set-property">g_object_set_property</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">),</span> <span class="string">"mix-matrix"</span><span class="gtkdoc opt">, &</span>v<span class="gtkdoc opt">);</span> 205<span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-unset">g_value_unset</a></span> <span class="gtkdoc opt">(&</span>v<span class="gtkdoc opt">);</span></pre></td> 206 </tr> 207 </tbody> 208 </table> 209</div> 210 211<p></p> 212</div> 213<div class="refsect3"> 214<a name="id-1.2.8.7.7"></a><h4>Example empty matrix launch line</h4> 215<div class="informalexample"> 216 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 217 <tbody> 218 <tr> 219 <td class="listing_lines" align="right"><pre>1</pre></td> 220 <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch<span class="gtkdoc opt">-</span><span class="number">1.0</span> <span class="gtkdoc opt">-</span>v audiotestsrc <span class="gtkdoc opt">!</span> audio<span class="gtkdoc opt">/</span>x<span class="gtkdoc opt">-</span>raw<span class="gtkdoc opt">,</span>channels<span class="gtkdoc opt">=</span><span class="number">8</span> <span class="gtkdoc opt">!</span> audioconvert mix<span class="gtkdoc opt">-</span>matrix<span class="gtkdoc opt">=</span><span class="string">"<>"</span> <span class="gtkdoc opt">!</span> audio<span class="gtkdoc opt">/</span>x<span class="gtkdoc opt">-</span>raw<span class="gtkdoc opt">,</span>channels<span class="gtkdoc opt">=</span><span class="number">16</span><span class="gtkdoc opt">,</span>channel<span class="gtkdoc opt">-</span>mask<span class="gtkdoc opt">=</span>\<span class="gtkdoc opt">(</span>bitmask\<span class="gtkdoc opt">)</span><span class="number">0x0000000000000000</span> <span class="gtkdoc opt">!</span> fakesink</pre></td> 221 </tr> 222 </tbody> 223 </table> 224</div> 225 226<p></p> 227</div> 228<div class="refsynopsisdiv"> 229<h2>Synopsis</h2> 230<div class="refsect2"> 231<a name="id-1.2.8.7.8.1"></a><h3>Element Information</h3> 232<div class="variablelist"><table border="0" class="variablelist"> 233<colgroup> 234<col align="left" valign="top"> 235<col> 236</colgroup> 237<tbody> 238<tr> 239<td><p><span class="term">plugin</span></p></td> 240<td> 241 <a class="link" href="gst-plugins-base-plugins-plugin-audioconvert.html#plugin-audioconvert">audioconvert</a> 242 </td> 243</tr> 244<tr> 245<td><p><span class="term">author</span></p></td> 246<td>Benjamin Otte <otte@gnome.org></td> 247</tr> 248<tr> 249<td><p><span class="term">class</span></p></td> 250<td>Filter/Converter/Audio</td> 251</tr> 252</tbody> 253</table></div> 254</div> 255<hr> 256<div class="refsect2"> 257<a name="id-1.2.8.7.8.2"></a><h3>Element Pads</h3> 258<div class="variablelist"><table border="0" class="variablelist"> 259<colgroup> 260<col align="left" valign="top"> 261<col> 262</colgroup> 263<tbody> 264<tr> 265<td><p><span class="term">name</span></p></td> 266<td>sink</td> 267</tr> 268<tr> 269<td><p><span class="term">direction</span></p></td> 270<td>sink</td> 271</tr> 272<tr> 273<td><p><span class="term">presence</span></p></td> 274<td>always</td> 275</tr> 276<tr> 277<td><p><span class="term">details</span></p></td> 278<td>audio/x-raw, format=(string){ S8, U8, S16LE, S16BE, U16LE, U16BE, S24_32LE, S24_32BE, U24_32LE, U24_32BE, S32LE, S32BE, U32LE, U32BE, S24LE, S24BE, U24LE, U24BE, S20LE, S20BE, U20LE, U20BE, S18LE, S18BE, U18LE, U18BE, F32LE, F32BE, F64LE, F64BE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string){ interleaved, non-interleaved }</td> 279</tr> 280</tbody> 281</table></div> 282<div class="variablelist"><table border="0" class="variablelist"> 283<colgroup> 284<col align="left" valign="top"> 285<col> 286</colgroup> 287<tbody> 288<tr> 289<td><p><span class="term">name</span></p></td> 290<td>src</td> 291</tr> 292<tr> 293<td><p><span class="term">direction</span></p></td> 294<td>source</td> 295</tr> 296<tr> 297<td><p><span class="term">presence</span></p></td> 298<td>always</td> 299</tr> 300<tr> 301<td><p><span class="term">details</span></p></td> 302<td>audio/x-raw, format=(string){ S8, U8, S16LE, S16BE, U16LE, U16BE, S24_32LE, S24_32BE, U24_32LE, U24_32BE, S32LE, S32BE, U32LE, U32BE, S24LE, S24BE, U24LE, U24BE, S20LE, S20BE, U20LE, U20BE, S18LE, S18BE, U18LE, U18BE, F32LE, F32BE, F64LE, F64BE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string){ interleaved, non-interleaved }</td> 303</tr> 304</tbody> 305</table></div> 306</div> 307</div> 308</div> 309<div class="refsect1"> 310<a name="gst-plugins-base-plugins-audioconvert.functions_details"></a><h2>Functions</h2> 311<p></p> 312</div> 313<div class="refsect1"> 314<a name="gst-plugins-base-plugins-audioconvert.other_details"></a><h2>Types and Values</h2> 315<div class="refsect2"> 316<a name="GstAudioConvert-struct"></a><h3>struct GstAudioConvert</h3> 317<pre class="programlisting">struct GstAudioConvert;</pre> 318<p>The audioconvert object structure.</p> 319</div> 320</div> 321<div class="refsect1"> 322<a name="gst-plugins-base-plugins-audioconvert.property-details"></a><h2>Property Details</h2> 323<div class="refsect2"> 324<a name="GstAudioConvert--dithering"></a><h3>The <code class="literal">“dithering”</code> property</h3> 325<pre class="programlisting"> “dithering” <a href="../html/gst-plugins-base-libs-GstAudioQuantize.html#GstAudioDitherMethod"><span class="type">GstAudioDitherMethod</span></a></pre> 326<p>Selects between different dithering methods.</p> 327<p>Flags: Read / Write</p> 328<p>Default value: GST_AUDIO_DITHER_TPDF</p> 329</div> 330<hr> 331<div class="refsect2"> 332<a name="GstAudioConvert--noise-shaping"></a><h3>The <code class="literal">“noise-shaping”</code> property</h3> 333<pre class="programlisting"> “noise-shaping” <a href="../html/gst-plugins-base-libs-GstAudioQuantize.html#GstAudioNoiseShapingMethod"><span class="type">GstAudioNoiseShapingMethod</span></a></pre> 334<p>Selects between different noise shaping methods.</p> 335<p>Flags: Read / Write</p> 336<p>Default value: GST_AUDIO_NOISE_SHAPING_NONE</p> 337</div> 338<hr> 339<div class="refsect2"> 340<a name="GstAudioConvert--mix-matrix"></a><h3>The <code class="literal">“mix-matrix”</code> property</h3> 341<pre class="programlisting"> “mix-matrix” <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstControlSource.html#GstValueArray"><span class="type">GstValueArray</span></a></pre> 342<p>Transformation matrix for input/output channels.</p> 343<p>Flags: Read / Write</p> 344</div> 345</div> 346</div> 347<div 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