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| <div class="refentry"> |
| <a name="gst-plugins-good-plugins-rganalysis"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-rganalysis.top_of_page"></a>rganalysis</span></h2> |
| <p>rganalysis</p> |
| </td> |
| <td class="gallery_image" valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.properties"></a><h2>Properties</h2> |
| <div class="informaltable"><table class="informaltable" border="0"> |
| <colgroup> |
| <col width="150px" class="properties_type"> |
| <col width="300px" class="properties_name"> |
| <col width="200px" class="properties_flags"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="property_type"><a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td> |
| <td class="property_name"><a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--forced" title="The “forced” property">forced</a></td> |
| <td class="property_flags">Read / Write</td> |
| </tr> |
| <tr> |
| <td class="property_type"><a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gint"><span class="type">gint</span></a></td> |
| <td class="property_name"><a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--num-tracks" title="The “num-tracks” property">num-tracks</a></td> |
| <td class="property_flags">Read / Write</td> |
| </tr> |
| <tr> |
| <td class="property_type"><a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></td> |
| <td class="property_name"><a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--reference-level" title="The “reference-level” property">reference-level</a></td> |
| <td class="property_flags">Read / Write</td> |
| </tr> |
| <tr> |
| <td class="property_type"><a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td> |
| <td class="property_name"><a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--message" title="The “message” property">message</a></td> |
| <td class="property_flags">Read / Write / Construct</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <a name="GstRgAnalysis"></a><div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.other"></a><h2>Types and Values</h2> |
| <div class="informaltable"><table class="informaltable" width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="name"> |
| <col class="description"> |
| </colgroup> |
| <tbody><tr> |
| <td class="datatype_keyword">struct</td> |
| <td class="function_name"><a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis-struct" title="struct GstRgAnalysis">GstRgAnalysis</a></td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="screen"> <a href="/usr/share/gtk-doc/html/gobjectgobject-The-Base-Object-Type.html#GObject-struct">GObject</a> |
| <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobjectgobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a> |
| <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstObject.html#GstObject-struct">GstObject</a> |
| <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstElement.html#GstElement-struct">GstElement</a> |
| <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-libs-1.0GstBaseTransform.html#GstBaseTransform-struct">GstBaseTransform</a> |
| <span class="lineart">╰──</span> GstRgAnalysis |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.description"></a><h2>Description</h2> |
| <p>This element analyzes raw audio sample data in accordance with the proposed</p> |
| <a class="ulink" href="http://replaygain.org" target="_top">ReplayGain standard</a> for |
| <p>calculating the ideal replay gain for music tracks and albums. The element |
| is designed as a pass-through filter that never modifies any data. As it |
| receives an EOS event, it finalizes the ongoing analysis and generates a tag |
| list containing the results. It is sent downstream with a tag event and |
| posted on the message bus with a tag message. The EOS event is forwarded as |
| normal afterwards. Result tag lists at least contain the tags |
| <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-TRACK-GAIN:CAPS"><span class="type">GST_TAG_TRACK_GAIN</span></a>, <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-TRACK-PEAK:CAPS"><span class="type">GST_TAG_TRACK_PEAK</span></a> and <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-REFERENCE-LEVEL:CAPS"><span class="type">GST_TAG_REFERENCE_LEVEL</span></a>.</p> |
| <p>Because the generated metadata tags become available at the end of streams, |
| downstream muxer and encoder elements are normally unable to save them in |
| their output since they generally save metadata in the file header. |
| Therefore, it is often necessary that applications read the results in a bus |
| event handler for the tag message. Obtaining the values this way is always |
| needed for album processing (see <a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--num-tracks" title="The “num-tracks” property"><span class="type">“num-tracks”</span></a> property) since |
| the album gain and peak values need to be associated with all tracks of an |
| album, not just the last one.</p> |
| <div class="refsect2"> |
| <a name="id-1.2.121.7.6"></a><h3>Example launch lines</h3> |
| <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">gst<span class="gtkdoc opt">-</span>launch<span class="gtkdoc opt">-</span><span class="number">1.0</span> <span class="gtkdoc opt">-</span>t audiotestsrc wave<span class="gtkdoc opt">=</span>sine num<span class="gtkdoc opt">-</span>buffers<span class="gtkdoc opt">=</span><span class="number">512</span> <span class="gtkdoc opt">!</span> rganalysis <span class="gtkdoc opt">!</span> fakesink</pre></td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| Analyze a simple test waveform |
| <div class="informalexample"> |
| <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> |
| <tbody> |
| <tr> |
| <td class="listing_lines" align="right"><pre>1 |
| 2</pre></td> |
| <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>t filesrc location<span class="gtkdoc opt">=</span>filename<span class="gtkdoc opt">.</span>ext <span class="gtkdoc opt">!</span> decodebin \ |
| <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audioresample <span class="gtkdoc opt">!</span> rganalysis <span class="gtkdoc opt">!</span> fakesink</pre></td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| Analyze a given file |
| <div class="informalexample"> |
| <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> |
| <tbody> |
| <tr> |
| <td class="listing_lines" align="right"><pre>1 |
| 2</pre></td> |
| <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>t gnomevfssrc location<span class="gtkdoc opt">=</span>http<span class="gtkdoc opt">:</span><span class="gtkdoc slc">//replaygain.hydrogenaudio.org/ref_pink.wav \</span> |
| <span class="gtkdoc opt">!</span> wavparse <span class="gtkdoc opt">!</span> rganalysis <span class="gtkdoc opt">!</span> fakesink</pre></td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| Analyze the pink noise reference file |
| <p> |
| The above launch line yields a result gain of +6 dB (instead of the expected |
| +0 dB). This is not in error, refer to the <a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--reference-level" title="The “reference-level” property"><span class="type">“reference-level”</span></a> |
| property documentation for more information. |
| </p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="id-1.2.121.7.7"></a><h3>Acknowledgements</h3> |
| <p> |
| This element is based on code used in the <a class="ulink" href="http://sjeng.org/vorbisgain.html" target="_top">vorbisgain</a> program and many |
| others. The relevant parts are copyrighted by David Robinson, Glen Sawyer |
| and Frank Klemm. |
| </p> |
| </div> |
| <div class="refsynopsisdiv"> |
| <h2>Synopsis</h2> |
| <div class="refsect2"> |
| <a name="id-1.2.121.7.8.1"></a><h3>Element Information</h3> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td><p><span class="term">plugin</span></p></td> |
| <td> |
| <a class="link" href="gst-plugins-good-plugins-plugin-replaygain.html#plugin-replaygain">replaygain</a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term">author</span></p></td> |
| <td>René Stadler <mail@renestadler.de></td> |
| </tr> |
| <tr> |
| <td><p><span class="term">class</span></p></td> |
| <td>Filter/Analyzer/Audio</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="id-1.2.121.7.8.2"></a><h3>Element Pads</h3> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <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, S16LE }, layout=(string)interleaved, channels=(int)1, rate=(int){ 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"></span></p></td> |
| <td> audio/x-raw, format=(string){ F32LE, S16LE }, layout=(string)interleaved, channels=(int)2, channel-mask=(bitmask)0x0000000000000003, rate=(int){ 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }</td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="variablelist"><table border="0" class="variablelist"> |
| <colgroup> |
| <col align="left" valign="top"> |
| <col> |
| </colgroup> |
| <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, S16LE }, layout=(string)interleaved, channels=(int)1, rate=(int){ 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }</td> |
| </tr> |
| <tr> |
| <td><p><span class="term"></span></p></td> |
| <td> audio/x-raw, format=(string){ F32LE, S16LE }, layout=(string)interleaved, channels=(int)2, channel-mask=(bitmask)0x0000000000000003, rate=(int){ 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000 }</td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.functions_details"></a><h2>Functions</h2> |
| <p></p> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.other_details"></a><h2>Types and Values</h2> |
| <div class="refsect2"> |
| <a name="GstRgAnalysis-struct"></a><h3>struct GstRgAnalysis</h3> |
| <pre class="programlisting">struct GstRgAnalysis;</pre> |
| <p>Opaque data structure.</p> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.property-details"></a><h2>Property Details</h2> |
| <div class="refsect2"> |
| <a name="GstRgAnalysis--forced"></a><h3>The <code class="literal">“forced”</code> property</h3> |
| <pre class="programlisting"> “forced” <a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre> |
| <p>Whether to analyze streams even when ReplayGain tags exist.</p> |
| <p>For assisting transcoder/converter applications, the element can silently |
| skip the processing of streams that already contain the necessary tags. |
| Data will flow as usual but the element will not consume CPU time and will |
| not generate result tags. To enable possible skipping, set this property |
| to <a href="/usr/share/gtk-doc/html/glibglib-Standard-Macros.html#FALSE:CAPS"><span class="type">FALSE</span></a>.</p> |
| <p>If used in conjunction with <a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--num-tracks" title="The “num-tracks” property">album |
| processing</a>, the element will skip the number of remaining album |
| tracks if a full set of tags is found for the first track. If a subsequent |
| track of the album is missing tags, processing cannot start again. If this |
| is undesired, the application has to scan all files beforehand and enable |
| forcing of processing if needed.</p> |
| <p>Flags: Read / Write</p> |
| <p>Default value: TRUE</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstRgAnalysis--num-tracks"></a><h3>The <code class="literal">“num-tracks”</code> property</h3> |
| <pre class="programlisting"> “num-tracks” <a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gint"><span class="type">gint</span></a></pre> |
| <p>Number of remaining album tracks.</p> |
| <p>Analyzing several streams sequentially and assigning them a common result |
| gain is known as "album processing". If this gain is used during playback |
| (by switching to "album mode"), all tracks of an album receive the same |
| amplification. This keeps the relative volume levels between the tracks |
| intact. To enable this, set this property to the number of streams that |
| will be processed as album tracks.</p> |
| <p>Every time an EOS event is received, the value of this property is |
| decremented by one. As it reaches zero, it is assumed that the last track |
| of the album finished. The tag list for the final stream will contain the |
| additional tags <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-ALBUM-GAIN:CAPS"><span class="type">GST_TAG_ALBUM_GAIN</span></a> and <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-ALBUM-PEAK:CAPS"><span class="type">GST_TAG_ALBUM_PEAK</span></a>. All other |
| streams just get the two track tags posted because the values for the album |
| tags are not known before all tracks are analyzed. Applications need to |
| ensure that the album gain and peak values are also associated with the |
| other tracks when storing the results.</p> |
| <p>If the total number of album tracks is unknown beforehand, just ensure that |
| the value is greater than 1 before each track starts. Then before the end |
| of the last track, set it to the value 1.</p> |
| <p>To perform album processing, the element has to preserve data between |
| streams. This cannot survive a state change to the NULL or READY state. |
| If you change your pipeline's state to NULL or READY between tracks, lock |
| the element's state using <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstElement.html#gst-element-set-locked-state"><code class="function">gst_element_set_locked_state()</code></a> when it is in |
| PAUSED or PLAYING.</p> |
| <p>Flags: Read / Write</p> |
| <p>Allowed values: >= 0</p> |
| <p>Default value: 0</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstRgAnalysis--reference-level"></a><h3>The <code class="literal">“reference-level”</code> property</h3> |
| <pre class="programlisting"> “reference-level” <a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></pre> |
| <p>Reference level [dB].</p> |
| <p>Analyzing the ReplayGain pink noise reference waveform computes a result of |
| +6 dB instead of the expected 0 dB. This is because the default reference |
| level is 89 dB. To obtain values as lined out in the original proposal of |
| ReplayGain, set this property to 83.</p> |
| <p>Almost all software uses 89 dB as a reference however, and this value has |
| become the new official value. That is to say, while the change has been |
| acclaimed by the author of the ReplayGain proposal, the <a class="ulink" href="http://replaygain.org" target="_top">webpage</a> is still outdated at the time |
| of this writing.</p> |
| <p>The value was changed because the original proposal recommends a default |
| pre-amp value of +6 dB for playback. This seemed a bit odd, as it means |
| that the algorithm has the general tendency to produce adjustment values |
| that are 6 dB too low. Bumping the reference level by 6 dB compensated for |
| this.</p> |
| <p>The problem of the reference level being ambiguous for lack of concise |
| standardization is to be solved by adopting the <a href="/usr/share/gtk-doc/html/gstreamer-1.0GstTagList.html#GST-TAG-REFERENCE-LEVEL:CAPS"><span class="type">GST_TAG_REFERENCE_LEVEL</span></a> |
| tag, which allows to store the used value alongside the gain values.</p> |
| <p>Flags: Read / Write</p> |
| <p>Allowed values: [0,150]</p> |
| <p>Default value: 89</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstRgAnalysis--message"></a><h3>The <code class="literal">“message”</code> property</h3> |
| <pre class="programlisting"> “message” <a href="/usr/share/gtk-doc/html/glibglib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre> |
| <p>Post statics messages.</p> |
| <p>Flags: Read / Write / Construct</p> |
| <p>Default value: FALSE</p> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.see-also"></a><h2>See Also</h2> |
| <p><a class="link" href="gst-plugins-good-plugins-rgvolume.html#GstRgVolume"><span class="type">GstRgVolume</span></a></p> |
| </div> |
| </div> |
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