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| <a href="#gst-plugins-good-plugins-rganalysis.synopsis" class="shortcut">Top</a> |
| | |
| <a href="#gst-plugins-good-plugins-rganalysis.description" class="shortcut">Description</a> |
| | |
| <a href="#gst-plugins-good-plugins-rganalysis.object-hierarchy" class="shortcut">Object Hierarchy</a> |
| | |
| <a href="#gst-plugins-good-plugins-rganalysis.properties" class="shortcut">Properties</a> |
| </td></tr> |
| </table> |
| <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 — Perform the ReplayGain analysis</p> |
| </td> |
| <td valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsynopsisdiv"> |
| <a name="gst-plugins-good-plugins-rganalysis.synopsis"></a><h2>Synopsis</h2> |
| <a name="GstRgAnalysis"></a><pre class="synopsis">struct <a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis-struct" title="struct GstRgAnalysis">GstRgAnalysis</a>; |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.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> |
| +----GstRgAnalysis |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.properties"></a><h2>Properties</h2> |
| <pre class="synopsis"> |
| "<a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--forced" title='The "forced" property'>forced</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-good-plugins-rganalysis.html#GstRgAnalysis--num-tracks" title='The "num-tracks" property'>num-tracks</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> : Read / Write |
| "<a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--reference-level" title='The "reference-level" property'>reference-level</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-good-plugins-rganalysis.html#GstRgAnalysis--message" title='The "message" property'>message</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write / Construct |
| </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 |
| <a class="ulink" href="http://replaygain.org" target="_top">ReplayGain standard</a> for |
| 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="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.html#GST-TAG-TRACK-GAIN:CAPS"><span class="type">GST_TAG_TRACK_GAIN</span></a>, <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.html#GST-TAG-TRACK-PEAK:CAPS"><span class="type">GST_TAG_TRACK_PEAK</span></a> and <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.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 <a class="link" href="gst-plugins-good-plugins-rganalysis.html#GstRgAnalysis--num-tracks" title='The "num-tracks" property'>album processing</a> |
| since the album gain and peak values need to be associated with all tracks of |
| an album, not just the last one. |
| </p> |
| <p> |
| </p> |
| <div class="refsect2"> |
| <a name="idp10160000"></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> |
| <p> |
| </p> |
| <hr> |
| <div class="refsect2"> |
| <a name="idp12540192"></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> |
| <p> |
| </p> |
| <div class="refsynopsisdiv"> |
| <h2>Synopsis</h2> |
| <div class="refsect2"> |
| <a name="idp14762528"></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-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="idp17191872"></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, 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"> |
| <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, 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> |
| <p> |
| </p> |
| </div> |
| <div class="refsect1"> |
| <a name="gst-plugins-good-plugins-rganalysis.details"></a><h2>Details</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="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</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="http://library.gnome.org/devel/glib/unstable/glib-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>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="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> : Read / Write</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="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.html#GST-TAG-ALBUM-GAIN:CAPS"><span class="type">GST_TAG_ALBUM_GAIN</span></a> and <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.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="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.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>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="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> : Read / Write</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="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstTagList.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>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="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write / Construct</pre> |
| <p>Post statics messages.</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> |
| <a class="link" href="gst-plugins-good-plugins-rgvolume.html#GstRgVolume"><span class="type">GstRgVolume</span></a> |
| </div> |
| </div> |
| <div class="footer"> |
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