mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-22 17:51:16 +00:00
cleanup of unused and forgoten sections fixed links from the manual and the pwg to the API docs added more notes to R...
Original commit message from CVS: cleanup of unused and forgoten sections fixed links from the manual and the pwg to the API docs added more notes to README
This commit is contained in:
parent
1a1c19bb74
commit
626cbdc8b2
37 changed files with 1222 additions and 982 deletions
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@ -144,6 +144,7 @@ GTK-DOC NOTES
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as well as $(MODULE)-decl.txt and $(MODULE)-decl-list.txt
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and .args, .hierarchy and .signals files are created
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gtkdoc-scan is called
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- if it not works, try e.g. 'rm docs/gst/*.stamp'
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* Possible errors and how to fix them
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- Warning: multiple "IDs" for constraint linkend: gst-tag-register.
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@ -9,21 +9,24 @@
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<!ENTITY GstBuffer SYSTEM "xml/gstbuffer.xml">
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<!ENTITY GstCaps SYSTEM "xml/gstcaps.xml">
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<!ENTITY GstClock SYSTEM "xml/gstclock.xml">
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<!ENTITY GstCompat SYSTEM "xml/gstcompat.xml">
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<!ENTITY GstConfig SYSTEM "xml/gstconfig.xml">
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<!ENTITY GstCpu SYSTEM "xml/gstcpu.xml">
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<!ENTITY GstData SYSTEM "xml/gstdata.xml">
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<!ENTITY GstElement SYSTEM "xml/gstelement.xml">
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<!ENTITY GstElementDetails SYSTEM "xml/gstelementdetails.xml">
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<!ENTITY GstElementFactory SYSTEM "xml/gstelementfactory.xml">
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<!ENTITY GstEnumTypes SYSTEM "xml/gstenumtypes.xml">
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<!ENTITY GstError SYSTEM "xml/gsterror.xml">
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<!ENTITY GstEvent SYSTEM "xml/gstevent.xml">
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<!ENTITY GstFilter SYSTEM "xml/gstfilter.xml">
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<!ENTITY GstFormat SYSTEM "xml/gstformat.xml">
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<!ENTITY GstGhostPad SYSTEM "xml/gstghostpad.xml">
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<!ENTITY GstImplementsInterface SYSTEM "xml/gstimplementsinterface.xml">
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<!ENTITY GstIndex SYSTEM "xml/gstindex.xml">
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<!ENTITY GstIndexFactory SYSTEM "xml/gstindexfactory.xml">
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<!ENTITY GstImplementsInterface SYSTEM "xml/gstimplementsinterface.xml">
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<!ENTITY GstInfo SYSTEM "xml/gstinfo.xml">
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<!ENTITY GstLog SYSTEM "xml/gstlog.xml">
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<!ENTITY GstMacros SYSTEM "xml/gstmacros.xml">
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<!ENTITY GstMemChunk SYSTEM "xml/gstmemchunk.xml">
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<!ENTITY GstObject SYSTEM "xml/gstobject.xml">
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<!ENTITY GstPad SYSTEM "xml/gstpad.xml">
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@ -34,6 +37,7 @@
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<!ENTITY GstPluginFeature SYSTEM "xml/gstpluginfeature.xml">
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<!ENTITY GstProbe SYSTEM "xml/gstprobe.xml">
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<!ENTITY GstQuery SYSTEM "xml/gstquery.xml">
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<!ENTITY GstQueue SYSTEM "xml/gstqueue.xml">
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<!ENTITY GstRealPad SYSTEM "xml/gstrealpad.xml">
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<!ENTITY GstRegistry SYSTEM "xml/gstregistry.xml">
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<!ENTITY GstRegistryPool SYSTEM "xml/gstregistrypool.xml">
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@ -45,14 +49,18 @@
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<!ENTITY GstTagSetter SYSTEM "xml/gsttagsetter.xml">
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<!ENTITY GstThread SYSTEM "xml/gstthread.xml">
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<!ENTITY GstTrace SYSTEM "xml/gsttrace.xml">
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<!ENTITY GstTrashStack SYSTEM "xml/gsttrashstack.xml">
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<!ENTITY GstTypeFind SYSTEM "xml/gsttypefind.xml">
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<!ENTITY GstTypeFindFactory SYSTEM "xml/gsttypefindfactory.xml">
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<!ENTITY GstUtils SYSTEM "xml/gstutils.xml">
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<!ENTITY GstTypes SYSTEM "xml/gsttypes.xml">
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<!ENTITY GstUriHandler SYSTEM "xml/gsturihandler.xml">
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<!ENTITY GstUriType SYSTEM "xml/gsturitype.xml">
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<!ENTITY GstUtils SYSTEM "xml/gstutils.xml">
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<!ENTITY GstValue SYSTEM "xml/gstvalue.xml">
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<!ENTITY GstVersion SYSTEM "xml/gstversion.xml">
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<!ENTITY GstXML SYSTEM "xml/gstxml.xml">
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<!ENTITY GstQueue SYSTEM "xml/gstqueue.xml">
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<!--
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<!ENTITY GstAggregator SYSTEM "xml/gstaggregator.xml">
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<!ENTITY GstFakeSrc SYSTEM "xml/gstfakesrc.xml">
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<!ENTITY GstFakeSink SYSTEM "xml/gstfakesink.xml">
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@ -65,7 +73,7 @@
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<!ENTITY GstStatistics SYSTEM "xml/gststatistics.xml">
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<!ENTITY GstMD5Sink SYSTEM "xml/gstmd5sink.xml">
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<!ENTITY GstTee SYSTEM "xml/gsttee.xml">
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-->
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<!ENTITY gstreamer-tree-index SYSTEM "xml/tree_index.sgml">
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<!ENTITY hash "#">
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@ -89,22 +97,24 @@
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&Gst;
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&GstBin;
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&GstBuffer;
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&GstConfig;
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&GstCaps;
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&GstClock;
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&GstConfig;
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&GstCpu;
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&GstData;
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&GstElement;
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&GstElementDetails;
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&GstElementFactory;
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&GstEnumTypes;
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&GstError;
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&GstEvent;
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&GstFilter;
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&GstFormat;
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&GstGhostPad;
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&GstImplementsInterface;
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&GstIndex;
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&GstIndexFactory;
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&GstInfo;
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&GstImplementsInterface;
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&GstObject;
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&GstPad;
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&GstPadTemplate;
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@ -127,9 +137,12 @@
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&GstThread;
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&GstTypeFind;
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&GstTypeFindFactory;
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&GstTypes;
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&GstUriHandler;
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&GstUriType;
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&GstUtils;
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&GstValue;
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&GstVersion;
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&GstXML;
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</chapter>
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@ -141,12 +154,24 @@
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</para>
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&GstAtomic;
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&GstMacros;
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&GstMemChunk;
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</chapter>
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<chapter id="gstreamer-compat">
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<title>GStreamer Core Compatibility</title>
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<para>
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Theses elements are defined for compatibillity with older code.
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The must not be use in new code!
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</para>
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&GstCompat;
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</chapter>
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<!--
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FIXME: why is this commented out
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FIXME: why is this commented out (reason #1: no public API)
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<chapter id="element-types">
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<title>GStreamer Standard Elements</title>
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@ -1438,6 +1438,8 @@ gst_scheduler_factory_get_type
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<SECTION>
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<FILE>gststructure</FILE>
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<TITLE>GstStructure</TITLE>
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GST_TYPE_STRUCTURE
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GstStructure
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GstStructureForeachFunc
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gst_structure_empty_new
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@ -1474,7 +1476,6 @@ gst_structure_from_string
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<SUBSECTION Standard>
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GST_STRUCTURE
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GST_IS_STRUCTURE
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GST_TYPE_STRUCTURE
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<SUBSECTION Private>
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gst_structure_get_type
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</SECTION>
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@ -1483,12 +1484,12 @@ gst_structure_get_type
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<FILE>gstsystemclock</FILE>
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<TITLE>GstSystemClock</TITLE>
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GstSystemClock
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GST_TYPE_SYSTEM_CLOCK
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gst_system_clock_obtain
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<SUBSECTION Standard>
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GstSystemClockClass
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GST_SYSTEM_CLOCK
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GST_IS_SYSTEM_CLOCK
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GST_TYPE_SYSTEM_CLOCK
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gst_system_clock_get_type
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GST_SYSTEM_CLOCK_CLASS
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GST_IS_SYSTEM_CLOCK_CLASS
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@ -1873,6 +1874,7 @@ gst_value_register_intersect_func
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<SECTION>
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<FILE>gstversion</FILE>
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<TITLE>GstVersion</TITLE>
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GST_VERSION_MAJOR
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GST_VERSION_MINOR
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GST_VERSION_MICRO
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@ -1,8 +1,8 @@
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<!-- ##### SECTION Title ##### -->
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gstcompat
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GstCompat
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<!-- ##### SECTION Short_Description ##### -->
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Deprecated API entries
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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@ -1,8 +1,8 @@
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<!-- ##### SECTION Title ##### -->
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gstmacros
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GstMacros
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<!-- ##### SECTION Short_Description ##### -->
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various portabillity helper macros
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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@ -14,6 +14,13 @@ Generic structure containing fields of names and values
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</para>
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<!-- ##### MACRO GST_TYPE_STRUCTURE ##### -->
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<para>
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</para>
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<!-- ##### STRUCT GstStructure ##### -->
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<para>
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@ -25,6 +25,13 @@ system time.
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@cond:
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@_gst_reserved:
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<!-- ##### MACRO GST_TYPE_SYSTEM_CLOCK ##### -->
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<para>
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</para>
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<!-- ##### FUNCTION gst_system_clock_obtain ##### -->
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<para>
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863
docs/gst/tmpl/gsttaglist.sgml
Normal file
863
docs/gst/tmpl/gsttaglist.sgml
Normal file
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@ -0,0 +1,863 @@
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<!-- ##### SECTION Title ##### -->
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GstTagList
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<!-- ##### SECTION Short_Description ##### -->
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List of tags and values used to describe media metadata
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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</para>
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<!-- ##### SECTION See_Also ##### -->
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<para>
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</para>
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<!-- ##### TYPEDEF GstTagList ##### -->
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<para>
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</para>
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<!-- ##### MACRO GST_TYPE_TAG_LIST ##### -->
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<para>
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</para>
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<!-- ##### ENUM GstTagMergeMode ##### -->
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<para>
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</para>
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@GST_TAG_MERGE_UNDEFINED:
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@GST_TAG_MERGE_REPLACE_ALL:
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@GST_TAG_MERGE_REPLACE:
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@GST_TAG_MERGE_APPEND:
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@GST_TAG_MERGE_PREPEND:
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@GST_TAG_MERGE_KEEP:
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@GST_TAG_MERGE_KEEP_ALL:
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@GST_TAG_MERGE_COUNT:
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<!-- ##### ENUM GstTagFlag ##### -->
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<para>
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</para>
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@GST_TAG_FLAG_UNDEFINED:
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@GST_TAG_FLAG_META:
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@GST_TAG_FLAG_ENCODED:
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@GST_TAG_FLAG_DECODED:
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@GST_TAG_FLAG_COUNT:
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<!-- ##### USER_FUNCTION GstTagForeachFunc ##### -->
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<para>
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</para>
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@list:
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@tag:
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@user_data:
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<!-- ##### USER_FUNCTION GstTagMergeFunc ##### -->
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<para>
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</para>
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@dest:
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@src:
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<!-- ##### FUNCTION gst_tag_register ##### -->
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<para>
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</para>
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@name:
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@flag:
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@type:
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@nick:
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@blurb:
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@func:
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<!-- ##### FUNCTION gst_tag_merge_use_first ##### -->
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<para>
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</para>
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@dest:
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@src:
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<!-- ##### FUNCTION gst_tag_merge_strings_with_comma ##### -->
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<para>
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</para>
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@dest:
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@src:
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<!-- ##### FUNCTION gst_tag_exists ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_get_type ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_get_nick ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_get_description ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_get_flag ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_is_fixed ##### -->
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<para>
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</para>
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@tag:
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@Returns:
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<!-- ##### FUNCTION gst_tag_list_new ##### -->
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<para>
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</para>
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@Returns:
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||||
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<!-- ##### FUNCTION gst_is_tag_list ##### -->
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<para>
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||||
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</para>
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@p:
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@Returns:
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||||
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||||
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<!-- ##### FUNCTION gst_tag_list_copy ##### -->
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<para>
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</para>
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@list:
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@Returns:
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||||
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||||
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<!-- ##### FUNCTION gst_tag_list_insert ##### -->
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<para>
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</para>
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@into:
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@from:
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@mode:
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<!-- ##### FUNCTION gst_tag_list_merge ##### -->
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<para>
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</para>
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@list1:
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@list2:
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@mode:
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||||
@Returns:
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||||
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||||
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||||
<!-- ##### FUNCTION gst_tag_list_free ##### -->
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<para>
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||||
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||||
</para>
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||||
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||||
@list:
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||||
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||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_tag_size ##### -->
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<para>
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||||
|
||||
</para>
|
||||
|
||||
@list:
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||||
@tag:
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||||
@Returns:
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||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_add ##### -->
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<para>
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||||
|
||||
</para>
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||||
|
||||
@list:
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||||
@mode:
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||||
@tag:
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||||
@Varargs:
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||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_add_values ##### -->
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||||
<para>
|
||||
|
||||
</para>
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||||
|
||||
@list:
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||||
@mode:
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||||
@tag:
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||||
@Varargs:
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||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_add_valist ##### -->
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||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
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||||
@mode:
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||||
@tag:
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||||
@var_args:
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||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_add_valist_values ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
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||||
@mode:
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||||
@tag:
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||||
@var_args:
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||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_remove_tag ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_foreach ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@func:
|
||||
@user_data:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_value_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_copy_value ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@dest:
|
||||
@list:
|
||||
@tag:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_char ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_char_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uchar ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uchar_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_boolean ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_boolean_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_int ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_int_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uint ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uint_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_long ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_long_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_ulong ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_ulong_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_int64 ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_int64_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uint64 ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_uint64_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_float ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_float_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_double ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_double_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_string ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_string_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_pointer ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_tag_list_get_pointer_index ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@tag:
|
||||
@index:
|
||||
@value:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_event_new_tag ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@list:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_event_tag_get_list ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@tag_event:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_TITLE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ARTIST ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ALBUM ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_DATE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_GENRE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_COMMENT ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_TRACK_NUMBER ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_TRACK_COUNT ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ALBUM_VOLUME_NUMBER ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ALBUM_VOLUME_COUNT ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_LOCATION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_DESCRIPTION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_VERSION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ISRC ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ORGANIZATION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_COPYRIGHT ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_CONTACT ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_LICENSE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_PERFORMER ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_DURATION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_CODEC ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_VIDEO_CODEC ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_AUDIO_CODEC ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_BITRATE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_NOMINAL_BITRATE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_MINIMUM_BITRATE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_MAXIMUM_BITRATE ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_SERIAL ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ENCODER ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ENCODER_VERSION ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_TRACK_GAIN ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_TRACK_PEAK ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ALBUM_GAIN ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TAG_ALBUM_PEAK ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
|
@ -1,8 +1,8 @@
|
|||
<!-- ##### SECTION Title ##### -->
|
||||
gsttypes
|
||||
GstTypes
|
||||
|
||||
<!-- ##### SECTION Short_Description ##### -->
|
||||
|
||||
various global enums and constants
|
||||
|
||||
<!-- ##### SECTION Long_Description ##### -->
|
||||
<para>
|
||||
|
|
141
docs/gst/tmpl/gsturihandler.sgml
Normal file
141
docs/gst/tmpl/gsturihandler.sgml
Normal file
|
@ -0,0 +1,141 @@
|
|||
<!-- ##### SECTION Title ##### -->
|
||||
GstUriHandler
|
||||
|
||||
<!-- ##### SECTION Short_Description ##### -->
|
||||
Plugin feature that handles URI types
|
||||
|
||||
<!-- ##### SECTION Long_Description ##### -->
|
||||
<para>
|
||||
The URIHandler is a pluginfeature that can be used to locate element
|
||||
and the element property that can handle a given URI.
|
||||
</para>
|
||||
|
||||
<!-- ##### SECTION See_Also ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
<!-- ##### STRUCT GstURIHandler ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_TYPE_URI_HANDLER ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
|
||||
<!-- ##### MACRO GST_URI_TYPE_IS_VALID ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@type:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_protocol_is_valid ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@protocol:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_is_valid ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@uri:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_get_protocol ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@uri:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_get_location ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@uri:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_construct ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@protocol:
|
||||
@location:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_element_make_from_uri ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@type:
|
||||
@uri:
|
||||
@elementname:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_handler_get_uri_type ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@handler:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_handler_get_protocols ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@handler:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_handler_get_uri ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@handler:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_handler_set_uri ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@handler:
|
||||
@uri:
|
||||
@Returns:
|
||||
|
||||
|
||||
<!-- ##### FUNCTION gst_uri_handler_new_uri ##### -->
|
||||
<para>
|
||||
|
||||
</para>
|
||||
|
||||
@handler:
|
||||
@uri:
|
||||
|
||||
|
|
@ -2,7 +2,7 @@
|
|||
GstURIType
|
||||
|
||||
<!-- ##### SECTION Short_Description ##### -->
|
||||
|
||||
describes URI types
|
||||
|
||||
<!-- ##### SECTION Long_Description ##### -->
|
||||
<para>
|
||||
|
|
|
@ -1,5 +1,5 @@
|
|||
<!-- ##### SECTION Title ##### -->
|
||||
gstutils
|
||||
GstUtils
|
||||
|
||||
<!-- ##### SECTION Short_Description ##### -->
|
||||
various utility functions
|
||||
|
|
|
@ -2,7 +2,7 @@
|
|||
gstversion
|
||||
|
||||
<!-- ##### SECTION Short_Description ##### -->
|
||||
|
||||
GStreamer version macros
|
||||
|
||||
<!-- ##### SECTION Long_Description ##### -->
|
||||
<para>
|
||||
|
|
|
@ -1,166 +0,0 @@
|
|||
<chapter id="chapter-threads">
|
||||
<title>Threads</title>
|
||||
<para>
|
||||
GStreamer has support for multithreading through the use of
|
||||
the <classname>GstThread</classname> object. This object is in fact
|
||||
a special <classname>GstBin</classname> that will become a thread when started.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
To construct a new thread you will perform something like:
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<programlisting>
|
||||
GstElement *my_thread;
|
||||
|
||||
/* create the thread object */
|
||||
my_thread = gst_thread_new ("my_thread");
|
||||
/* you could have used gst_element_factory_make ("thread", "my_thread"); */
|
||||
g_return_if_fail (my_thread != NULL);
|
||||
|
||||
/* add some plugins */
|
||||
gst_bin_add (GST_BIN (my_thread), GST_ELEMENT (funky_src));
|
||||
gst_bin_add (GST_BIN (my_thread), GST_ELEMENT (cool_effect));
|
||||
|
||||
/* link the elements here... */
|
||||
...
|
||||
|
||||
/* start playing */
|
||||
gst_element_set_state (GST_ELEMENT (my_thread), GST_STATE_PLAYING);
|
||||
|
||||
</programlisting>
|
||||
</para>
|
||||
<para>
|
||||
The above program will create a thread with two elements in it. As soon
|
||||
as it is set to the PLAYING state, the thread will start to iterate
|
||||
itself. You never need to explicitly iterate a thread.
|
||||
</para>
|
||||
|
||||
<sect1 id="section-threads-constraints">
|
||||
<title>Constraints placed on the pipeline by the GstThread</title>
|
||||
<para>
|
||||
Within the pipeline, everything is the same as in any other bin. The
|
||||
difference lies at the thread boundary, at the link between the
|
||||
thread and the outside world (containing bin). Since GStreamer is
|
||||
fundamentally buffer-oriented rather than byte-oriented, the natural
|
||||
solution to this problem is an element that can "buffer" the buffers
|
||||
between the threads, in a thread-safe fashion. This element is the
|
||||
queue, described more fully in <xref linkend="chapter-queues"/>. It doesn't
|
||||
matter if the queue is placed in the containing bin or in the thread
|
||||
itself, but it needs to be present on one side or the other to enable
|
||||
inter-thread communication.
|
||||
</para>
|
||||
</sect1>
|
||||
<sect1 id="section-threads-when">
|
||||
<title>When would you want to use a thread?</title>
|
||||
<para>
|
||||
If you are writing a GUI application, making the top-level bin a thread will make your GUI
|
||||
more responsive. If it were a pipeline instead, it would have to be iterated by your
|
||||
application's event loop, which increases the latency between events (say, keyboard presses)
|
||||
and responses from the GUI. In addition, any slight hang in the GUI would delay iteration of
|
||||
the pipeline, which (for example) could cause pops in the output of the sound card, if it is
|
||||
an audio pipeline.
|
||||
</para>
|
||||
<para>
|
||||
<xref linkend="section-threads-img"/> shows how a thread can be visualised.
|
||||
</para>
|
||||
<figure float="1" id="section-threads-img">
|
||||
<title>A thread</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/thread.ℑ" format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
</figure>
|
||||
|
||||
<para>
|
||||
As an example we show the helloworld program using a thread.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<programlisting>
|
||||
/* example-begin threads.c */
|
||||
#include <gst/gst.h>
|
||||
|
||||
/* we set this to TRUE right before gst_main (), but there could still
|
||||
be a race condition between setting it and entering the function */
|
||||
gboolean can_quit = FALSE;
|
||||
|
||||
/* eos will be called when the src element has an end of stream */
|
||||
void
|
||||
eos (GstElement *src, gpointer data)
|
||||
{
|
||||
GstThread *thread = GST_THREAD (data);
|
||||
g_print ("have eos, quitting\n");
|
||||
|
||||
/* stop the bin */
|
||||
gst_element_set_state (GST_ELEMENT (thread), GST_STATE_NULL);
|
||||
|
||||
while (!can_quit) /* waste cycles */ ;
|
||||
gst_main_quit ();
|
||||
}
|
||||
|
||||
int
|
||||
main (int argc, char *argv[])
|
||||
{
|
||||
GstElement *filesrc, *demuxer, *decoder, *converter, *audiosink;
|
||||
GstElement *thread;
|
||||
|
||||
if (argc < 2) {
|
||||
g_print ("usage: %s <Ogg/Vorbis filename>\n", argv[0]);
|
||||
exit (-1);
|
||||
}
|
||||
|
||||
gst_init (&argc, &argv);
|
||||
|
||||
/* create a new thread to hold the elements */
|
||||
thread = gst_thread_new ("thread");
|
||||
g_assert (thread != NULL);
|
||||
|
||||
/* create a disk reader */
|
||||
filesrc = gst_element_factory_make ("filesrc", "disk_source");
|
||||
g_assert (filesrc != NULL);
|
||||
g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);
|
||||
g_signal_connect (G_OBJECT (filesrc), "eos",
|
||||
G_CALLBACK (eos), thread);
|
||||
|
||||
/* create an ogg demuxer */
|
||||
demuxer = gst_element_factory_make ("oggdemux", "demuxer");
|
||||
g_assert (demuxer != NULL);
|
||||
|
||||
/* create a vorbis decoder */
|
||||
decoder = gst_element_factory_make ("vorbisdec", "decoder");
|
||||
g_assert (decoder != NULL);
|
||||
|
||||
/* create an audio converter */
|
||||
converter = gst_element_factory_make ("audioconvert", "converter");
|
||||
g_assert (decoder != NULL);
|
||||
|
||||
/* and an audio sink */
|
||||
audiosink = gst_element_factory_make ("osssink", "play_audio");
|
||||
g_assert (audiosink != NULL);
|
||||
|
||||
/* add objects to the thread */
|
||||
gst_bin_add_many (GST_BIN (thread), filesrc, demuxer, decoder, converter, audiosink, NULL);
|
||||
/* link them in the logical order */
|
||||
gst_element_link_many (filesrc, demuxer, decoder, converter, audiosink, NULL);
|
||||
|
||||
/* start playing */
|
||||
gst_element_set_state (thread, GST_STATE_PLAYING);
|
||||
|
||||
/* do whatever you want here, the thread will be playing */
|
||||
g_print ("thread is playing\n");
|
||||
|
||||
can_quit = TRUE;
|
||||
gst_main ();
|
||||
|
||||
gst_object_unref (GST_OBJECT (thread));
|
||||
|
||||
exit (0);
|
||||
}
|
||||
/* example-end threads.c */
|
||||
</programlisting>
|
||||
</para>
|
||||
</sect1>
|
||||
</chapter>
|
|
@ -92,6 +92,7 @@
|
|||
</para>
|
||||
</sect1>
|
||||
<sect1 id="section-autoplug-cache">
|
||||
<!-- FIXME: this is outdated, there is no GstAutoplugCache in gst-0.8.X -->
|
||||
<title>Using the <classname>GstAutoplugCache</classname> element</title>
|
||||
<para>
|
||||
The <classname>GstAutoplugCache</classname> element is used to cache the
|
||||
|
|
|
@ -1,65 +0,0 @@
|
|||
<chapter id="chapter-buffers">
|
||||
<title>Buffers</title>
|
||||
<para>
|
||||
Buffers contain the data that will flow through the pipeline you have
|
||||
created. A source element will typically create a new buffer and pass
|
||||
it through a pad to the next element in the chain. When using the
|
||||
GStreamer infrastructure to create a media pipeline you will not have
|
||||
to deal with buffers yourself; the elements will do that for you.
|
||||
</para>
|
||||
<para>
|
||||
A buffer consists of:
|
||||
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>
|
||||
a pointer to a piece of memory.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
the size of the memory.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a timestamp for the buffer.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
A refcount that indicates how many elements are using this
|
||||
buffer. This refcount will be used to destroy the buffer when no
|
||||
element has a reference to it.
|
||||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
GStreamer provides functions to create custom buffer create/destroy algorithms, called
|
||||
a <classname>GstBufferPool</classname>. This makes it possible to efficiently
|
||||
allocate and destroy buffer memory. It also makes it possible to exchange memory between
|
||||
elements by passing the <classname>GstBufferPool</classname>. A video element can,
|
||||
for example, create a custom buffer allocation algorithm that creates buffers with XSHM
|
||||
as the buffer memory. An element can use this algorithm to create and fill the buffer
|
||||
with data.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The simple case is that a buffer is created, memory allocated, data put
|
||||
in it, and passed to the next element. That element reads the data, does
|
||||
something (like creating a new buffer and decoding into it), and
|
||||
unreferences the buffer. This causes the data to be freed and the buffer
|
||||
to be destroyed. A typical MPEG audio decoder works like this.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
A more complex case is when the filter modifies the data in place. It
|
||||
does so and simply passes on the buffer to the next element. This is just
|
||||
as easy to deal with. An element that works in place has to be careful when
|
||||
the buffer is used in more than one element; a copy on write has to made in this
|
||||
situation.
|
||||
</para>
|
||||
|
||||
</chapter>
|
|
@ -1,118 +0,0 @@
|
|||
<chapter id="chapter-elements">
|
||||
<title>Elements</title>
|
||||
<para>
|
||||
The most important object in <application>GStreamer</application> for the
|
||||
application programmer is the <classname>GstElement</classname> object.
|
||||
</para>
|
||||
|
||||
<sect1 id="section-elements-design">
|
||||
<title>What is an element ?</title>
|
||||
<para>
|
||||
An element is the basic building block for the media pipeline.
|
||||
All the different high-level components you are going to use are
|
||||
derived from <classname>GstElement</classname>. This means that a
|
||||
lot of functions you are going to use operate on objects of this class.
|
||||
</para>
|
||||
<para>
|
||||
Elements, from the perspective of GStreamer, are viewed as "black boxes"
|
||||
with a number of different aspects. One of these aspects is the presence
|
||||
of "pads" (see <xref linkend="chapter-pads"/>), or link points. This terminology arises from soldering;
|
||||
pads are where wires can be attached.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="section-elements-types">
|
||||
<title>Types of elements</title>
|
||||
|
||||
<sect2 id="section-elements-src">
|
||||
<title>Source elements</title>
|
||||
<para>
|
||||
Source elements generate data for use by a pipeline, for example
|
||||
reading from disk or from a sound card.
|
||||
</para>
|
||||
<para>
|
||||
<xref linkend="section-element-srcimg"/> shows how we will visualise
|
||||
a source element.
|
||||
We always draw a source pad to the right of the element.
|
||||
</para>
|
||||
<figure float="1" id="section-element-srcimg">
|
||||
<title>Visualisation of a source element</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/src-element.ℑ" format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
</figure>
|
||||
<para>
|
||||
Source elements do not accept data, they only generate data. You can
|
||||
see this in the figure because it only has a source pad. A source
|
||||
pad can only generate data.
|
||||
</para>
|
||||
</sect2>
|
||||
|
||||
<sect2 id="section-elements-filter">
|
||||
<title>Filters and codecs</title>
|
||||
<para>
|
||||
Filter elements have both input and output pads. They operate on
|
||||
data they receive in their sink pads and produce data on their source
|
||||
pads. For example, MPEG decoders and volume filters would fall into
|
||||
this category.
|
||||
</para>
|
||||
<para>
|
||||
Elements are not constrained as to the number of pads they might have;
|
||||
for example, a video mixer might have two input pads (the images of
|
||||
the two different video streams) and one output pad.
|
||||
</para>
|
||||
<figure float="1" id="section-element-filterimg">
|
||||
<title>Visualisation of a filter element</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/filter-element.ℑ" format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
</figure>
|
||||
<para>
|
||||
<xref linkend="section-element-filterimg"/> shows how we will visualise
|
||||
a filter element.
|
||||
This element has one sink (input) pad and one source (output) pad.
|
||||
Sink pads are drawn on the left of the element.
|
||||
</para>
|
||||
<figure float="1" id="section-element-multifilterimg">
|
||||
<title>Visualisation of a filter element with
|
||||
more than one output pad</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/filter-element-multi.ℑ"
|
||||
format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
</figure>
|
||||
<para>
|
||||
<xref linkend="section-element-multifilterimg"/> shows the visualisation of a filter element with
|
||||
more than one output pad. An example of such a filter is the AVI
|
||||
demultiplexer. This element will parse the input data and
|
||||
extract the audio and video data. Most of these filters dynamically
|
||||
send out a signal when a new pad is created so that the application
|
||||
programmer can link an arbitrary element to the newly created pad.
|
||||
</para>
|
||||
</sect2>
|
||||
|
||||
<sect2 id="section-elements-sink">
|
||||
<title>Sink elements</title>
|
||||
<para>
|
||||
Sink elements are end points in a media pipeline. They accept
|
||||
data but do not produce anything. Disk writing, soundcard playback,
|
||||
and video output would all be implemented by sink elements.
|
||||
<xref linkend="section-element-sinkimg"/> shows a sink element.
|
||||
</para>
|
||||
<figure float="1" id="section-element-sinkimg">
|
||||
<title>Visualisation of a sink element</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/sink-element.ℑ" format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
</figure>
|
||||
</sect2>
|
||||
</sect1>
|
||||
</chapter>
|
|
@ -1,279 +0,0 @@
|
|||
<chapter id="chapter-hello-world">
|
||||
<title>Your first application</title>
|
||||
<para>
|
||||
This chapter describes the most rudimentary aspects of a
|
||||
<application>GStreamer</application> application, including initializing
|
||||
the libraries, creating elements, packing them into a pipeline and playing,
|
||||
pausing and stopping the pipeline.
|
||||
</para>
|
||||
|
||||
<sect1 id="section-hello-world">
|
||||
<title>Hello world</title>
|
||||
<para>
|
||||
We will create a simple first application, a complete MP3 player, using
|
||||
standard <application>GStreamer</application> components. The player
|
||||
will read from a file that is given as the first argument to the program.
|
||||
</para>
|
||||
|
||||
<programlisting>
|
||||
/* example-begin helloworld.c */
|
||||
#include <gst/gst.h>
|
||||
|
||||
int
|
||||
main (int argc, char *argv[])
|
||||
{
|
||||
GstElement *pipeline, *filesrc, *decoder, *audiosink;
|
||||
|
||||
gst_init(&argc, &argv);
|
||||
|
||||
if (argc != 2) {
|
||||
g_print ("usage: %s <mp3 filename>\n", argv[0]);
|
||||
exit (-1);
|
||||
}
|
||||
|
||||
/* create a new pipeline to hold the elements */
|
||||
pipeline = gst_pipeline_new ("pipeline");
|
||||
|
||||
/* create a disk reader */
|
||||
filesrc = gst_element_factory_make ("filesrc", "disk_source");
|
||||
g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);
|
||||
|
||||
/* now it's time to get the decoder */
|
||||
decoder = gst_element_factory_make ("mad", "decoder");
|
||||
|
||||
/* and an audio sink */
|
||||
audiosink = gst_element_factory_make ("osssink", "play_audio");
|
||||
|
||||
/* add objects to the main pipeline */
|
||||
gst_bin_add_many (GST_BIN (pipeline), filesrc, decoder, audiosink, NULL);
|
||||
|
||||
/* link src to sink */
|
||||
gst_element_link_many (filesrc, decoder, audiosink, NULL);
|
||||
|
||||
/* start playing */
|
||||
gst_element_set_state (pipeline, GST_STATE_PLAYING);
|
||||
|
||||
while (gst_bin_iterate (GST_BIN (pipeline)));
|
||||
|
||||
/* stop the pipeline */
|
||||
gst_element_set_state (pipeline, GST_STATE_NULL);
|
||||
|
||||
/* we don't need a reference to these objects anymore */
|
||||
gst_object_unref (GST_OBJECT (pipeline));
|
||||
/* unreffing the pipeline unrefs the contained elements as well */
|
||||
|
||||
exit (0);
|
||||
}
|
||||
/* example-end helloworld.c */
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
Let's go through this example step by step.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The first thing you have to do is to include the standard
|
||||
<application>GStreamer</application> headers and
|
||||
initialize the framework.
|
||||
</para>
|
||||
<programlisting>
|
||||
|
||||
#include <gst/gst.h>
|
||||
|
||||
...
|
||||
|
||||
int
|
||||
main (int argc, char *argv[])
|
||||
{
|
||||
...
|
||||
gst_init(&argc, &argv);
|
||||
...
|
||||
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
We are going to create three elements and one pipeline. Since all
|
||||
elements share the same base type, <classname>GstElement</classname>,
|
||||
we can define them as:
|
||||
</para>
|
||||
<programlisting>
|
||||
...
|
||||
GstElement *pipeline, *filesrc, *decoder, *audiosink;
|
||||
...
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
Next, we are going to create an empty pipeline. As you have seen in
|
||||
the basic introduction, this pipeline will hold and manage all the
|
||||
elements we are going to pack into it.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* create a new pipeline to hold the elements */
|
||||
pipeline = gst_pipeline_new ("pipeline");
|
||||
</programlisting>
|
||||
<para>
|
||||
We use the standard constructor for a pipeline: gst_pipeline_new ().
|
||||
</para>
|
||||
|
||||
<para>
|
||||
We then create a disk source element. The disk source element is able to
|
||||
read from a file. We use the standard GObject property mechanism to set
|
||||
a property of the element: the file to read from.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* create a disk reader */
|
||||
filesrc = gst_element_factory_make ("filesrc", "disk_source");
|
||||
g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);
|
||||
</programlisting>
|
||||
<note>
|
||||
<para>
|
||||
You can check if the filesrc != NULL to verify the creation of the
|
||||
disk source element.
|
||||
</para>
|
||||
</note>
|
||||
|
||||
<para>
|
||||
We now create the MP3 decoder element. This assumes that the 'mad' plugin
|
||||
is installed on the system where this application is executed.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* now it's time to get the decoder */
|
||||
decoder = gst_element_factory_make ("mad", "decoder");
|
||||
</programlisting>
|
||||
<para>
|
||||
gst_element_factory_make() takes two arguments: a string that will
|
||||
identify the element you need and a second argument: how you want
|
||||
to name the element. The name of the element is something you can
|
||||
choose yourself and might be used to retrieve the element from a
|
||||
bin/pipeline.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Finally we create our audio sink element. This element will be able
|
||||
to play back the audio using OSS.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* and an audio sink */
|
||||
audiosink = gst_element_factory_make ("osssink", "play_audio");
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
We then add the elements to the pipeline.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* add objects to the main pipeline */
|
||||
gst_bin_add_many (GST_BIN (pipeline), filesrc, decoder, audiosink, NULL);
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
We link the different pads of the elements together like this:
|
||||
</para>
|
||||
<programlisting>
|
||||
/* link src to sink */
|
||||
gst_element_link_many (filesrc, decoder, audiosink, NULL);
|
||||
</programlisting>
|
||||
|
||||
<para>
|
||||
We now have created a complete pipeline. We can visualise the
|
||||
pipeline as follows:
|
||||
</para>
|
||||
<figure float="1" id="section-hello-img">
|
||||
<title>The "hello world" pipeline</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/hello-world.ℑ" format="&IMAGE;" />
|
||||
</imageobject>
|
||||
</mediaobject>
|
||||
|
||||
</figure>
|
||||
|
||||
<para>
|
||||
Everything is now set up to start streaming. We use the following
|
||||
statements to change the state of the pipeline:
|
||||
</para>
|
||||
<programlisting>
|
||||
/* start playing */
|
||||
gst_element_set_state (pipeline, GST_STATE_PLAYING);
|
||||
|
||||
</programlisting>
|
||||
<note>
|
||||
<para>
|
||||
<application>GStreamer</application> will take care of the READY and PAUSED state for
|
||||
you when going from NULL to PLAYING.
|
||||
</para>
|
||||
</note>
|
||||
|
||||
<para>
|
||||
Since we do not use threads, nothing will happen yet. We have to
|
||||
call gst_bin_iterate() to execute one iteration of the pipeline.
|
||||
</para>
|
||||
<programlisting>
|
||||
while (gst_bin_iterate (GST_BIN (pipeline)));
|
||||
</programlisting>
|
||||
<para>
|
||||
The gst_bin_iterate() function will return TRUE as long as something
|
||||
interesting happened inside the pipeline. When the end-of-file has been
|
||||
reached the _iterate function will return FALSE and we can end the loop.
|
||||
</para>
|
||||
<programlisting>
|
||||
/* stop the pipeline */
|
||||
gst_element_set_state (pipeline, GST_STATE_NULL);
|
||||
|
||||
gst_object_unref (GST_OBJECT (pipeline));
|
||||
|
||||
exit (0);
|
||||
</programlisting>
|
||||
<note>
|
||||
<para>
|
||||
Don't forget to set the state of the pipeline to NULL. This will free
|
||||
all of the resources held by the elements.
|
||||
</para>
|
||||
</note>
|
||||
|
||||
</sect1>
|
||||
|
||||
<sect1 id="section-hello-world-compile">
|
||||
<title>Compiling helloworld.c</title>
|
||||
<para>
|
||||
To compile the helloworld example, use:
|
||||
</para>
|
||||
<programlisting>
|
||||
gcc -Wall `pkg-config gstreamer-&GST_MAJORMINOR; --cflags --libs` helloworld.c \
|
||||
-o helloworld
|
||||
</programlisting>
|
||||
<para>
|
||||
We use pkg-config to get the compiler flags needed to compile
|
||||
this application. Make sure to have your PKG_CONFIG_PATH environment
|
||||
variable set to the correct location if you are building this
|
||||
application against the uninstalled location.
|
||||
</para>
|
||||
<para>
|
||||
You can run the example with
|
||||
(substitute helloworld.mp3 with you favorite MP3 file):
|
||||
</para>
|
||||
<programlisting>
|
||||
./helloworld helloworld.mp3
|
||||
</programlisting>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="section-hello-world-conclusion">
|
||||
<title>Conclusion</title>
|
||||
<para>
|
||||
This concludes our first example. As you see, setting up a pipeline
|
||||
is very low-level but powerful. You will see later in this manual how
|
||||
you can create a custom MP3 element with a higher-level API.
|
||||
</para>
|
||||
<para>
|
||||
It should be clear from the example that we can very easily replace the
|
||||
filesrc element with the gnomevfssrc element, giving you instant streaming
|
||||
from any gnomevfs URL.
|
||||
</para>
|
||||
<para>
|
||||
We can also choose to use another type of sink instead of the audiosink.
|
||||
We could use a filesink to write the raw samples to a file, for example.
|
||||
It should also be clear that inserting filters, like a stereo effect,
|
||||
into the pipeline is not that hard to do. The most important thing is
|
||||
that you can reuse already existing elements.
|
||||
</para>
|
||||
</sect1>
|
||||
</chapter>
|
|
@ -1,243 +0,0 @@
|
|||
<chapter id="chapter-pads">
|
||||
<title>Pads</title>
|
||||
<para>
|
||||
As we have seen in <xref linkend="chapter-elements"/>, the pads are the element's
|
||||
interface to the outside world.
|
||||
</para>
|
||||
<para>
|
||||
The specific type of media that the element can handle will be exposed by the pads.
|
||||
The description of this media type is done with capabilities(see
|
||||
<xref linkend="section-caps"/>)
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Pads are either source or sink pads. The terminology is defined from the
|
||||
view of the element itself: elements accept data on their sink pads, and
|
||||
send data out on their source pads. Sink pads are drawn on the left,
|
||||
while source pads are drawn on the right of an element. In general,
|
||||
data flows from left to right in the graph.<footnote>
|
||||
<para>
|
||||
In reality, there is no objection to data flowing from a
|
||||
source pad to the sink pad of an element upstream. Data will, however,
|
||||
always flow from a source pad of one element to the sink pad of
|
||||
another.
|
||||
</para></footnote>
|
||||
</para>
|
||||
|
||||
<sect1 id="section-pads-type">
|
||||
<title>Types of pad</title>
|
||||
|
||||
<sect2 id="section-pads-dynamic">
|
||||
<title>Dynamic pads</title>
|
||||
<para>
|
||||
Some elements might not have all of their pads when the element is
|
||||
created. This
|
||||
can happen, for example, with an MPEG system demultiplexer. The
|
||||
demultiplexer will create its pads at runtime when it detects the
|
||||
different elementary streams in the MPEG system stream.
|
||||
</para>
|
||||
<para>
|
||||
Running <application>gst-inspect mpegdemux</application> will show that
|
||||
the element has only one pad: a sink pad called 'sink'. The other pads are
|
||||
"dormant". You can see this in the pad template because there is
|
||||
an 'Exists: Sometimes'
|
||||
property. Depending on the type of MPEG file you play, the pads will
|
||||
be created. We
|
||||
will see that this is very important when you are going to create dynamic
|
||||
pipelines later on in this manual.
|
||||
</para>
|
||||
</sect2>
|
||||
<sect2 id="section-pads-request">
|
||||
<title>Request pads</title>
|
||||
<para>
|
||||
An element can also have request pads. These pads are not created
|
||||
automatically but are only created on demand. This is very useful
|
||||
for multiplexers, aggregators and tee elements.
|
||||
</para>
|
||||
<para>
|
||||
The tee element, for example, has one input pad and a request padtemplate for the
|
||||
output pads. Whenever an element wants to get an output pad from the tee element, it
|
||||
has to request the pad.
|
||||
</para>
|
||||
</sect2>
|
||||
|
||||
</sect1>
|
||||
|
||||
<sect1 id="section-caps">
|
||||
<title>Capabilities of a pad</title>
|
||||
<para>
|
||||
Since the pads play a very important role in how the element is viewed by the
|
||||
outside world, a mechanism is implemented to describe the data that can
|
||||
flow through the pad by using capabilities.
|
||||
</para>
|
||||
<para>
|
||||
We will briefly describe what capabilities are, enough for you to get a basic understanding
|
||||
of the concepts. You will find more information on how to create capabilities in the
|
||||
Plugin Writer's Guide.
|
||||
</para>
|
||||
|
||||
<sect2 id="section-pads-caps">
|
||||
<title>Capabilities</title>
|
||||
<para>
|
||||
Capabilities are attached to a pad in order to describe
|
||||
what type of media the pad can handle.
|
||||
</para>
|
||||
<para>
|
||||
Capabilities is shorthand for "capability chain". A capability chain
|
||||
is a chain of one capability or more.
|
||||
</para>
|
||||
<para>
|
||||
The basic entity is a capability, and is defined by a name, a MIME
|
||||
type and a set of properties. A capability can be chained to
|
||||
another capability, which is why we commonly refer to a chain of
|
||||
capability entities as "capabilities".
|
||||
<footnote>
|
||||
<para>
|
||||
It is important to understand that the term "capabilities" refers
|
||||
to a chain of one capability or more. This will be clearer when
|
||||
you see the structure definition of a <classname>GstCaps</classname>
|
||||
element.
|
||||
</para>
|
||||
</footnote>
|
||||
</para>
|
||||
<para>
|
||||
Below is a dump of the capabilities of the element mad, as shown by
|
||||
<command>gst-inspect</command>.
|
||||
You can see two pads: sink and src. Both pads have capability information attached to them.
|
||||
</para>
|
||||
<para>
|
||||
The sink pad (input pad) is called 'sink' and takes data of MIME type 'audio/mp3'. It also has
|
||||
three properties: layer, bitrate and framed.
|
||||
</para>
|
||||
<para>
|
||||
The source pad (output pad) is called 'src' and outputs data of
|
||||
MIME type 'audio/raw'. It also has four properties: format, depth,
|
||||
rate and channels.
|
||||
</para>
|
||||
<programlisting>
|
||||
Pads:
|
||||
SINK template: 'sink'
|
||||
Availability: Always
|
||||
Capabilities:
|
||||
'mad_sink':
|
||||
MIME type: 'audio/mp3':
|
||||
|
||||
SRC template: 'src'
|
||||
Availability: Always
|
||||
Capabilities:
|
||||
'mad_src':
|
||||
MIME type: 'audio/raw':
|
||||
format: String: int
|
||||
endianness: Integer: 1234
|
||||
width: Integer: 16
|
||||
depth: Integer: 16
|
||||
channels: Integer range: 1 - 2
|
||||
law: Integer: 0
|
||||
signed: Boolean: TRUE
|
||||
rate: Integer range: 11025 - 48000
|
||||
</programlisting>
|
||||
</sect2>
|
||||
<sect2 id="section-pads-props">
|
||||
<title>What are properties ?</title>
|
||||
<para>
|
||||
Properties are used to describe extra information for
|
||||
capabilities. A property consists of a key (a string) and
|
||||
a value. There are different possible value types that can be used:
|
||||
</para>
|
||||
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>
|
||||
basic types:
|
||||
</para>
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>
|
||||
an integer value: the property has this exact value.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a boolean value: the property is either TRUE or FALSE.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a fourcc value: this is a value that is commonly used to
|
||||
describe an encoding for video,
|
||||
as used for example by the AVI specification.
|
||||
<footnote><para>
|
||||
fourcc values consist of four bytes.
|
||||
<ulink url="http://www.fourcc.org" type="http">The FOURCC
|
||||
Definition List</ulink> is the most complete resource
|
||||
on the allowed fourcc values.
|
||||
</para></footnote>
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a float value: the property has this exact floating point value.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a string value.
|
||||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
</listitem>
|
||||
|
||||
<listitem>
|
||||
<para>
|
||||
range types:
|
||||
</para>
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>
|
||||
an integer range value: the property denotes a range of
|
||||
possible integers. For example, the wavparse element has
|
||||
a source pad where the "rate" property can go from 8000 to
|
||||
48000.
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a float range value: the property denotes a range of possible
|
||||
floating point values.
|
||||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
a list value: the property can take any value from a list of
|
||||
basic value types or range types.
|
||||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
|
||||
</sect2>
|
||||
<sect2 id="section-pads-caps-use">
|
||||
<title>What capabilities are used for</title>
|
||||
<para>
|
||||
Capabilities describe in great detail the type of media that is handled by the pads.
|
||||
They are mostly used for:
|
||||
</para>
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>
|
||||
Autoplugging: automatically finding plugins for a set of capabilities
|
||||
</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>
|
||||
Compatibility detection: when two pads are linked, <application>GStreamer</application>
|
||||
can verify if the two pads are talking about the same media types.
|
||||
The process of linking two pads and checking if they are compatible
|
||||
is called "caps negotiation".
|
||||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
</sect2>
|
||||
</sect1>
|
||||
</chapter>
|
|
@ -119,7 +119,8 @@
|
|||
</programlisting>
|
||||
<para>
|
||||
Note that the above code assumes that the mp3player bin derives itself
|
||||
from a <classname>GstThread</classname>, which begins to play as soon
|
||||
from a <ulink type="http"
|
||||
url="../../gstreamer/html/GstThread.html"><classname>GstThread</classname></ulink>, which begins to play as soon
|
||||
as its state is set to PLAYING. Other bin types may need explicit
|
||||
iteration. For more information, see <xref linkend="chapter-threads"/>.
|
||||
</para>
|
||||
|
@ -137,7 +138,8 @@
|
|||
This is where "ghost pads" come into play.
|
||||
</para>
|
||||
<figure float="1" id="section-bin-noghost-img">
|
||||
<title>Visualisation of a <classname>GstBin</classname> element without ghost pads</title>
|
||||
<title>Visualisation of a <ulink type="http"
|
||||
url="../../gstreamer/html/GstBin.html"><classname>GstBin</classname></ulink> element without ghost pads</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/bin-element-noghost.ℑ" format="&IMAGE;" />
|
||||
|
@ -152,7 +154,8 @@
|
|||
</para>
|
||||
|
||||
<figure float="1" id="section-bin-ghost-img">
|
||||
<title>Visualisation of a <classname>GstBin</classname> element with a ghost pad</title>
|
||||
<title>Visualisation of a <ulink type="http"
|
||||
url="../../gstreamer/html/GstBin.html"><classname>GstBin</classname></ulink> element with a ghost pad</title>
|
||||
<mediaobject>
|
||||
<imageobject>
|
||||
<imagedata fileref="images/bin-element-ghost.ℑ" format="&IMAGE;" />
|
||||
|
@ -165,8 +168,9 @@
|
|||
of the bin.
|
||||
</para>
|
||||
<para>
|
||||
Ghost pads can actually be added to all <classname>GstElement</classname>s and not just
|
||||
<classname>GstBin</classname>s. Use the following code example to add a ghost pad to a bin:
|
||||
Ghost pads can actually be added to all <ulink type="http"
|
||||
url="../../gstreamer/html/GstElement.html"><classname>GstElement</classname></ulink>s and not just
|
||||
<ulink type="http" url="../../gstreamer/html/GstBin.html"><classname>GstBin</classname></ulink>s. Use the following code example to add a ghost pad to a bin:
|
||||
</para>
|
||||
<programlisting>
|
||||
GstElement *bin;
|
||||
|
|
|
@ -37,6 +37,7 @@
|
|||
</para>
|
||||
|
||||
<para>
|
||||
<!-- FIXME: this is outdated, there is no GstBufferPool in gst-0.8.X -->
|
||||
GStreamer provides functions to create custom buffer create/destroy algorithms, called
|
||||
a <classname>GstBufferPool</classname>. This makes it possible to efficiently
|
||||
allocate and destroy buffer memory. It also makes it possible to exchange memory between
|
||||
|
|
|
@ -6,7 +6,9 @@
|
|||
from other user-space threading libraries in that they are scheduled explictly by GStreamer.
|
||||
</para>
|
||||
<para>
|
||||
A cothread is created by a <classname>GstBin</classname> whenever an element is found
|
||||
A cothread is created by a <ulink type="http"
|
||||
url="../../gstreamer/html/GstBin.html"><classname>GstBin</classname></ulink>
|
||||
whenever an element is found
|
||||
inside the bin that has one or more of the following properties:
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
|
@ -25,7 +27,8 @@
|
|||
</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
The <classname>GstBin</classname> will create a cothread context for all the elements
|
||||
The <ulink type="http" url="../../gstreamer/html/GstBin.html"><classname>GstBin
|
||||
</classname></ulink> will create a cothread context for all the elements
|
||||
in the bin so that the elements will interact in cooperative
|
||||
multithreading.
|
||||
</para>
|
||||
|
@ -117,7 +120,9 @@ chain_function (GstPad *pad, GstBuffer *buffer)
|
|||
bytestream library will need to be loop-based.
|
||||
</para>
|
||||
<para>
|
||||
There is no problem in putting cothreaded elements into a <classname>GstThread</classname> to
|
||||
There is no problem in putting cothreaded elements into a <ulink
|
||||
type="http" url="../../gstreamer/html/GstThread.html"><classname>GstThread
|
||||
</classname></ulink> to
|
||||
create even more complex pipelines with both user and kernel space threads.
|
||||
</para>
|
||||
|
||||
|
|
|
@ -3,9 +3,12 @@
|
|||
<sect1 id="section-elements-create">
|
||||
<title>Creating a GstElement</title>
|
||||
<para>
|
||||
A <classname>GstElement</classname> object is created from
|
||||
a factory. To create an element, you have to get access to a
|
||||
<classname>GstElementFactory</classname> object using a unique
|
||||
A <ulink type="http"
|
||||
url="../../gstreamer/html/GstElement.html"><classname>GstElement</classname></ulink>
|
||||
object is created from a factory.
|
||||
To create an element, you have to get access to a
|
||||
<ulink type="http" url="../../gstreamer/html/GstElementFactory.html">
|
||||
<classname>GstElementFactory</classname></ulink> object using a unique
|
||||
factory name.
|
||||
</para>
|
||||
<para>
|
||||
|
@ -58,14 +61,16 @@
|
|||
<sect1 id="section-elements-properties">
|
||||
<title>GstElement properties</title>
|
||||
<para>
|
||||
A <classname>GstElement</classname> can have several properties
|
||||
A <ulink type="http" url="../../gstreamer/html/GstElement.html">
|
||||
<classname>GstElement</classname></ulink> can have several properties
|
||||
which are implemented using standard <classname>GObject</classname>
|
||||
properties. The usual <classname>GObject</classname> methods to query,
|
||||
set and get property values and <classname>GParamSpecs</classname>
|
||||
are therefore supported.
|
||||
</para>
|
||||
<para>
|
||||
Every <classname>GstElement</classname> inherits at least
|
||||
Every <ulink type="http" url="../../gstreamer/html/GstElementFactory.html">
|
||||
<classname>GstElement</classname></ulink> inherits at least
|
||||
one property of its parent <classname>GstObject</classname>:
|
||||
the "name" property. This is the name you provide to the
|
||||
functions <function>gst_element_factory_make</function> or
|
||||
|
@ -108,7 +113,8 @@
|
|||
<sect1 id="section-elements-signals">
|
||||
<title>GstElement signals</title>
|
||||
<para>
|
||||
A <classname>GstElement</classname> also provides various
|
||||
A <ulink type="http" url="../../gstreamer/html/GstElementFactory.html">
|
||||
<classname>GstElement</classname></ulink> also provides various
|
||||
<classname>GObject</classname> signals that can be used as a flexible
|
||||
callback mechanism.
|
||||
</para>
|
||||
|
|
|
@ -2,7 +2,9 @@
|
|||
<title>Elements</title>
|
||||
<para>
|
||||
The most important object in <application>GStreamer</application> for the
|
||||
application programmer is the <classname>GstElement</classname> object.
|
||||
application programmer is the <ulink type="http"
|
||||
url="../../gstreamer/html/GstElement.html"><classname>GstElement</classname>
|
||||
</ulink>object.
|
||||
</para>
|
||||
|
||||
<sect1 id="section-elements-design">
|
||||
|
@ -10,14 +12,16 @@
|
|||
<para>
|
||||
An element is the basic building block for the media pipeline.
|
||||
All the different high-level components you are going to use are
|
||||
derived from <classname>GstElement</classname>. This means that a
|
||||
derived from <ulink type="http" url="../../gstreamer/html/GstElement.html">
|
||||
<classname>GstElement</classname></ulink>. This means that a
|
||||
lot of functions you are going to use operate on objects of this class.
|
||||
</para>
|
||||
<para>
|
||||
Elements, from the perspective of GStreamer, are viewed as "black boxes"
|
||||
with a number of different aspects. One of these aspects is the presence
|
||||
of "pads" (see <xref linkend="chapter-pads"/>), or link points. This terminology arises from soldering;
|
||||
pads are where wires can be attached.
|
||||
of "pads" (see <xref linkend="chapter-pads"/>), or link points.
|
||||
This terminology arises from soldering; pads are where wires can be
|
||||
attached.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
|
|
|
@ -93,7 +93,8 @@ main (int argc, char *argv[])
|
|||
|
||||
<para>
|
||||
We are going to create three elements and one pipeline. Since all
|
||||
elements share the same base type, <classname>GstElement</classname>,
|
||||
elements share the same base type, <ulink type="http"
|
||||
url="../../gstreamer/html/GstElement.html"><classname>GstElement</classname></ulink>,
|
||||
we can define them as:
|
||||
</para>
|
||||
<programlisting>
|
||||
|
|
|
@ -59,19 +59,22 @@
|
|||
|
||||
</programlisting>
|
||||
<para>
|
||||
You can query if a pad is linked with GST_PAD_IS_LINKED (pad).
|
||||
You can query if a pad is linked with
|
||||
<function>GST_PAD_IS_LINKED (pad)</function>.
|
||||
</para>
|
||||
<para>
|
||||
To query for the <classname>GstPad</classname> a pad is linked to, use
|
||||
gst_pad_get_peer (pad).
|
||||
To query for the <ulink type="http"
|
||||
url="../../gstreamer/html/GstPad.html"><classname>GstPad</classname></ulink>
|
||||
a pad is linked to, use <function>gst_pad_get_peer (pad)</function>.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="section-link-filtered">
|
||||
<title>Making filtered links</title>
|
||||
<para>
|
||||
You can also force a specific media type on the link by using gst_pad_link_filtered ()
|
||||
and gst_element_link_filtered () with capabilities.
|
||||
You can also force a specific media type on the link by using
|
||||
<function>gst_pad_link_filtered ()</function>
|
||||
and <function>gst_element_link_filtered ()</function> with capabilities.
|
||||
See <xref linkend="section-caps"/> for
|
||||
an explanation of capabilities.
|
||||
</para>
|
||||
|
|
|
@ -123,9 +123,11 @@
|
|||
|
||||
For a gentle introduction to this system, you may wish to read the
|
||||
<emphasis><ulink url="http://www.gtk.org/tutorial/" type="http">GTK+
|
||||
Tutorial</ulink></emphasis> or Eric Harlow's book <emphasis>Developing
|
||||
Linux Applications with GTK+ and GDK</emphasis>.
|
||||
|
||||
Tutorial</ulink></emphasis>, Eric Harlow's book <emphasis>Developing
|
||||
Linux Applications with GTK+ and GDK</emphasis> and the <emphasis>
|
||||
<ulink type="http"
|
||||
url="http://www.le-hacker.org/papers/gobject/index.html">Glib Object
|
||||
system</ulink></emphasis>.
|
||||
</para>
|
||||
</partintro>
|
||||
|
||||
|
|
|
@ -190,8 +190,9 @@ struct _GstCaps {
|
|||
<para>
|
||||
As we said, a capability has a name, a mime-type and some
|
||||
properties. The signature of the function to create a new
|
||||
<classname>GstCaps</classname> structure is:
|
||||
|
||||
<ulink type="http" url="../../gstreamer/html/gstreamer-GstCaps.html">
|
||||
<classname>GstCaps</classname></ulink> structure is:
|
||||
<!-- FIXME: GstProbs are deprecated, in gst-0.8.X -->
|
||||
<programlisting>
|
||||
GstCaps* gst_caps_new (const gchar *name, const gchar *mime, GstProps *props);
|
||||
</programlisting>
|
||||
|
|
|
@ -95,8 +95,9 @@
|
|||
<para>
|
||||
It is important to understand that the term "capabilities" refers
|
||||
to a chain of one capability or more. This will be clearer when
|
||||
you see the structure definition of a <classname>GstCaps</classname>
|
||||
element.
|
||||
you see the structure definition of a <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstCaps.html"><classname>GstCaps
|
||||
</classname></ulink>element.
|
||||
</para>
|
||||
</footnote>
|
||||
</para>
|
||||
|
|
|
@ -2,8 +2,10 @@
|
|||
<title>Threads</title>
|
||||
<para>
|
||||
GStreamer has support for multithreading through the use of
|
||||
the <classname>GstThread</classname> object. This object is in fact
|
||||
a special <classname>GstBin</classname> that will become a thread when started.
|
||||
the <ulink type="http" url="../../gstreamer/html/GstThread.html"><classname>
|
||||
GstThread</classname></ulink> object. This object is in fact
|
||||
a special <ulink type="http" url="../../gstreamer/html/GstBin.html"><classname>
|
||||
GstBin</classname></ulink> that will become a thread when started.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
|
|
|
@ -158,9 +158,13 @@ gst_my_filter_handle_src_event (GstPad *pad,
|
|||
<para>
|
||||
In this chapter follows a list of all defined events that are currently
|
||||
being used, plus how they should be used/interpreted. Events are stored
|
||||
in a <classname>GstEvent</classname> structure, which is simply a big
|
||||
C union with the types for each event in it. For the next development
|
||||
cycle, we intend to switch events over to <classname>GstStructure</classname>,
|
||||
in a <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstEvent.html"><classname>GstEvent
|
||||
</classname></ulink> structure, which is simply a big C union with the
|
||||
types for each event in it. For the next development cycle, we intend to
|
||||
switch events over to <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstStructure.html"><classname>GstStructure
|
||||
</classname></ulink>,
|
||||
but you don't need to worry about that too much for now.
|
||||
</para>
|
||||
<para>
|
||||
|
@ -194,7 +198,7 @@ gst_my_filter_handle_src_event (GstPad *pad,
|
|||
<xref linkend="section-loopfn-multiinput"/>.
|
||||
</para>
|
||||
<para>
|
||||
The EOS event (<classname>GST_EVENT_EOS</classname>) has no properties,
|
||||
The EOS event (<symbol>GST_EVENT_EOS</symbol>) has no properties,
|
||||
and that makes it one of the simplest events in &GStreamer;. It is
|
||||
created using <function>gst_event_new (GST_EVENT_EOS);</function>.
|
||||
</para>
|
||||
|
@ -246,12 +250,12 @@ gst_my_filter_handle_src_event (GstPad *pad,
|
|||
and a modified event should be sent on. The last is true for demuxers,
|
||||
which generally have a byte-to-time conversion concept. Their input
|
||||
is usually byte-based, so the incoming event will have an offset in
|
||||
byte units (<classname>GST_FORMAT_BYTES</classname>), too. Elements
|
||||
byte units (<symbol>GST_FORMAT_BYTES</symbol>), too. Elements
|
||||
downstream, however, expect discontinuity events in time units, so that
|
||||
it can be used to update the pipeline clock. Therefore, demuxers and
|
||||
similar elements should not forward the event, but parse it, free it
|
||||
and send a new discontinuity event (in time units,
|
||||
<classname>GST_FORMAT_TIME</classname>) further downstream.
|
||||
<symbol>GST_FORMAT_TIME</symbol>) further downstream.
|
||||
</para>
|
||||
<para>
|
||||
The discontinuity event is created using the function
|
||||
|
|
|
@ -37,7 +37,9 @@
|
|||
at their own will. We've also created a small extension to
|
||||
<classname>GTypeInterface</classname> (which is static itself, too) which
|
||||
allows us to query for interface availability based on runtime properties.
|
||||
This extension is called <classname>GstImplementsInterface</classname>.
|
||||
This extension is called <ulink type="http"
|
||||
url="../../gstreamer/html/GstImplementsInterface.html"><classname>
|
||||
GstImplementsInterface</classname></ulink>.
|
||||
</para>
|
||||
<para>
|
||||
One important note: interfaces do <emphasis>not</emphasis> replace
|
||||
|
@ -57,13 +59,16 @@
|
|||
will be notified of doing that wrongly when using the element: it will
|
||||
quit with failed assertions, which will explain what went wrong. In the
|
||||
case of GStreamer, the only dependency that <emphasis>some</emphasis>
|
||||
interfaces have is <classname>GstImplementsInterface</classname>. Per
|
||||
interfaces have is <ulink type="http"
|
||||
url="../../gstreamer/html/GstImplementsInterface.html"><classname>
|
||||
GstImplementsInterface</classname></ulink>. Per
|
||||
interface, we will indicate clearly when it depends on this extension.
|
||||
If it does, you need to register support for <emphasis>that</emphasis>
|
||||
interface before registering support for the interface that you're
|
||||
wanting to support. The example below explains how to add support for a
|
||||
simple interface with no further dependencies. For a small explanation
|
||||
on <classname>GstImplementsInterface</classname>, see the next section
|
||||
on <ulink type="http" url="../../gstreamer/html/GstImplementsInterface.html">
|
||||
<classname>GstImplementsInterface</classname></ulink>, see the next section
|
||||
about the mixer interface: <xref linkend="section-iface-mixer"/>.
|
||||
</para>
|
||||
<programlisting>
|
||||
|
@ -127,13 +132,16 @@ gst_my_filter_some_interface_init (GstSomeInterface *iface)
|
|||
and input/output settings.
|
||||
</para>
|
||||
<para>
|
||||
The mixer interface requires the <classname>GstImplementsInterface</classname>
|
||||
The mixer interface requires the <ulink type="http"
|
||||
url="../../gstreamer/html/GstImplementsInterface.html"><classname>
|
||||
GstImplementsInterface</classname></ulink>
|
||||
interface to be implemented by the element. The example below will
|
||||
feature both, so it serves as an example for the
|
||||
<classname>GstImplementsInterface</classname>, too. In the
|
||||
<classname>GstImplementsInterface</classname>, it is required to set a
|
||||
function pointer for the <function>supported ()</function> function. If
|
||||
you don't, this function will always return FALSE (default
|
||||
feature both, so it serves as an example for the <ulink type="http"
|
||||
url="../../gstreamer/html/GstImplementsInterface.html"><classname>
|
||||
GstImplementsInterface</classname></ulink>, too. In this
|
||||
interface, it is required to set a function pointer for the <function>
|
||||
supported ()</function> function.
|
||||
If you don't, this function will always return FALSE (default
|
||||
implementation) and the mixer interface implementation will not work. For
|
||||
the mixer interface, the only required function is
|
||||
<function>list_tracks ()</function>. All other function pointers in the
|
||||
|
@ -307,7 +315,9 @@ gst_my_filter_mixer_interface_init (GstMixerClass *iface)
|
|||
highly analog-video-centric.
|
||||
</para>
|
||||
<para>
|
||||
This interface requires the <classname>GstImplemensInterface</classname>
|
||||
This interface requires the <ulink type="http"
|
||||
url="../../gstreamer/html/GstImplementsInterface.html"><classname>
|
||||
GstImplemensInterface</classname></ulink>
|
||||
interface to work correctly.
|
||||
</para>
|
||||
<para>
|
||||
|
@ -454,7 +464,7 @@ gst_my_filter_tuner_interface_init (GstTunerClass *iface)
|
|||
<para>
|
||||
Property probing stores the list of allowed (or recommended) values in a
|
||||
<classname>GValueArray</classname> and returns that to the user.
|
||||
<classname>NULL</classname> is a valid return value, too. The process of
|
||||
<symbol>NULL</symbol> is a valid return value, too. The process of
|
||||
property probing is separated over two virtual functions: one for probing
|
||||
the property to create a <classname>GValueArray</classname>, and one to
|
||||
retrieve the current <classname>GValueArray</classname>. Those two are
|
||||
|
@ -462,12 +472,13 @@ gst_my_filter_tuner_interface_init (GstTunerClass *iface)
|
|||
this simpliies interface implementation in elements. For the application,
|
||||
there are functions that wrap those two. For more information on this,
|
||||
have a look at the API reference for the
|
||||
<!-- FIXME: add link, but this is in ./gst-plugins/gst-libs/gst/propertyprobe/propertyprobe.c-->
|
||||
<classname>GstPropertyProbe</classname> interface.
|
||||
</para>
|
||||
<para>
|
||||
Below is a example of property probing for the audio filter element; it
|
||||
will probe for allowed values for the <quote>silent</quote> property.
|
||||
Indeed, this value is a <classname>gboolean</classname> so it doesn't
|
||||
Indeed, this value is a <type>gboolean</type> so it doesn't
|
||||
make much sense. Then again, it's only an example.
|
||||
</para>
|
||||
<programlisting>
|
||||
|
|
|
@ -32,21 +32,32 @@
|
|||
once as streaminfo.
|
||||
</para>
|
||||
<para>
|
||||
<!-- FIXME: (Company knows about this)
|
||||
when people are interested in tags, they should connect to the pipeline's 'found-tag' signal and use that
|
||||
the code example on that page is bogus, too btw
|
||||
there are no string => something else g_value_transforms
|
||||
either use gst_value_deserialize or a custom deserialization (which is a better idea most of the time)
|
||||
-->
|
||||
A tag reading element is called <classname>TagGetter</classname> in
|
||||
&GStreamer;. A tag writer is called <classname>TagSetter</classname>. An
|
||||
element supporting both can be used in a tag editor for quick tag changing.
|
||||
&GStreamer;.
|
||||
A tag writer is called <ulink type="http"
|
||||
url="../../gstreamer/html/GstTagSetter.html"><classname>TagSetter</classname></ulink>.
|
||||
An element supporting both can be used in a tag editor for quick tag
|
||||
changing.
|
||||
</para>
|
||||
|
||||
<sect1 id="section-tagging-read" xreflabel="Reading Tags from Streams">
|
||||
<title>Reading Tags from Streams</title>
|
||||
<para>
|
||||
The basic object for tags is a <classname>GstTagList</classname>. An
|
||||
element that is reading tags from a stream should create an empty taglist
|
||||
and fill this with individual tags. Empty tag lists can be created with
|
||||
<function>gst_tag_list_new ()</function>. Then, the element can fill the
|
||||
list using <function>gst_tag_list_add_values ()</function>. Note that
|
||||
an element probably reads metadata as strings, but values might not
|
||||
necessarily be strings. Be sure to use <function>gst_value_transform ()</function>
|
||||
The basic object for tags is a <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstTagList.html"><classname>GstTagList
|
||||
</classname></ulink>. An element that is reading tags from a stream should
|
||||
create an empty taglist and fill this with individual tags. Empty tag
|
||||
lists can be created with <function>gst_tag_list_new ()</function>. Then,
|
||||
the element can fill the list using <function>gst_tag_list_add_values ()
|
||||
</function>. Note that an element probably reads metadata as strings, but
|
||||
values might not necessarily be strings. Be sure to use
|
||||
<function>gst_value_transform ()</function>
|
||||
to make sure that your data is of the right type. After data reading, the
|
||||
application can be notified of the new taglist by calling
|
||||
<function>gst_element_found_tags ()</function>. The tags should also be
|
||||
|
@ -160,7 +171,7 @@ gst_my_filter_class_init (GstMyFilterClass *klass)
|
|||
reader, too. Application tags are tags provided to the element via the
|
||||
TagSetter interface (which is just a layer). Pipeline tags are tags
|
||||
provided to the element from within the pipeline. The element receives
|
||||
such tags via the <classname>GST_EVENT_TAG</classname> event, which means
|
||||
such tags via the <symbol>GST_EVENT_TAG</symbol> event, which means
|
||||
that tags writers should automatically be event aware. The tag writer is
|
||||
responsible for combining all these three into one list and writing them
|
||||
to the output stream.
|
||||
|
|
|
@ -63,11 +63,12 @@ gst_my_filter_init (GstMyFilter *filter)
|
|||
is the process where the linked pads decide on the streamtype that will
|
||||
transfer between them. A full list of type-definitions can be found in
|
||||
<xref linkend="chapter-building-types"/>. A <function>_link ()</function>
|
||||
receives a pointer to a <classname>GstCaps</classname> struct that
|
||||
defines the proposed streamtype, and can respond with either
|
||||
<quote>yes</quote> (<classname>GST_PAD_LINK_OK</classname>),
|
||||
<quote>no</quote> (<classname>GST_PAD_LINK_REFUSED</classname>) or
|
||||
<quote>don't know yet</quote> (<classname>GST_PAD_LINK_DELAYED</classname>).
|
||||
receives a pointer to a <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstCaps.html"><classname>GstCaps</classname>
|
||||
</ulink> struct that defines the proposed streamtype, and can respond with
|
||||
either <quote>yes</quote> (<symbol>GST_PAD_LINK_OK</symbol>),
|
||||
<quote>no</quote> (<symbol>GST_PAD_LINK_REFUSED</symbol>) or
|
||||
<quote>don't know yet</quote> (<symbol>GST_PAD_LINK_DELAYED</symbol>).
|
||||
If the element responds positively towards the streamtype, that type
|
||||
will be used on the pad. An example:
|
||||
</para>
|
||||
|
@ -115,8 +116,11 @@ gst_my_filter_link (GstPad *pad,
|
|||
In here, we check the mimetype of the provided caps. Normally, you don't
|
||||
need to do that in your own plugin/element, because the core does that
|
||||
for you. We simply use it to show how to retrieve the mimetype from a
|
||||
provided set of caps. Types are stored in <classname>GstStructure</classname>
|
||||
internally. A <classname>GstCaps</classname> is nothing more than a small
|
||||
provided set of caps. Types are stored in <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstStructure.html"><classname>GstStructure
|
||||
</classname></ulink> internally. A <ulink
|
||||
type="http" url="../../gstreamer/html/gstreamer-GstCaps.html"><classname>GstCaps
|
||||
</classname></ulink> is nothing more than a small
|
||||
wrapper for 0 or more structures/types. From the structure, you can also
|
||||
retrieve properties, as is shown above with the function
|
||||
<function>gst_structure_get_int ()</function>.
|
||||
|
|
|
@ -5,53 +5,53 @@
|
|||
<para>
|
||||
A state describes whether the element instance is initialized, whether it
|
||||
is ready to transfer data and whether it is currently handling data. There
|
||||
are four states defined in &GStreamer;: <classname>GST_STATE_NULL</classname>,
|
||||
<classname>GST_STATE_READY</classname>, <classname>GST_STATE_PAUSED</classname>
|
||||
and <classname>GST_STATE_PLAYING</classname>.
|
||||
are four states defined in &GStreamer;: <symbol>GST_STATE_NULL</symbol>,
|
||||
<symbol>GST_STATE_READY</symbol>, <symbol>GST_STATE_PAUSED</symbol>
|
||||
and <symbol>GST_STATE_PLAYING</symbol>.
|
||||
</para>
|
||||
<para>
|
||||
<classname>GST_STATE_NULL</classname> (from now on referred to as
|
||||
<symbol>GST_STATE_NULL</symbol> (from now on referred to as
|
||||
<quote>NULL</quote>) is the default state of an element. In this state, it
|
||||
has not allocated any runtime resources, it has not loaded any runtime
|
||||
libraries and it can obviously not handle data.
|
||||
</para>
|
||||
<para>
|
||||
<classname>GST_STATE_READY</classname> (from now on referred to as
|
||||
<symbol>GST_STATE_READY</symbol> (from now on referred to as
|
||||
<quote>READY</quote>) is the next state that an element can be in. In the
|
||||
READY state, an element has all default resources (runtime-libraries,
|
||||
runtime-memory) allocated. However, it has not yet allocated or defined
|
||||
anything that is stream-specific. When going from NULL to READY state
|
||||
(<classname>GST_STATE_NULL_TO_READY</classname>), an element should
|
||||
(<symbol>GST_STATE_NULL_TO_READY</symbol>), an element should
|
||||
allocate any non-stream-specific resources and should load runtime-loadable
|
||||
libraries (if any). When going the other way around (from READY to NULL,
|
||||
<classname>GST_STATE_READY_TO_NULL</classname>), an element should unload
|
||||
<symbol>GST_STATE_READY_TO_NULL</symbol>), an element should unload
|
||||
these libraries and free all allocated resources. Examples of such
|
||||
resources are hardware devices. Note that files are generally streams,
|
||||
and these should thus be considered as stream-specific resources; therefore,
|
||||
they should <emphasis>not</emphasis> be allocated in this state.
|
||||
</para>
|
||||
<para>
|
||||
<classname>GST_STATE_PAUSED</classname> (from now on referred to as
|
||||
<symbol>GST_STATE_PAUSED</symbol> (from now on referred to as
|
||||
<quote>PAUSED</quote>) is a state in which an element is by all means able
|
||||
to handle data; the only 'but' here is that it doesn't actually handle
|
||||
any data. When going from the READY state into the PAUSED state
|
||||
(<classname>GST_STATE_READY_TO_PAUSED</classname>), the element will
|
||||
(<symbol>GST_STATE_READY_TO_PAUSED</symbol>), the element will
|
||||
usually not do anything at all: all stream-specific info is generally
|
||||
handled in the <function>_link ()</function>, which is called during caps
|
||||
negotiation. Exceptions to this rule are, for example, files: these are
|
||||
considered stream-specific data (since one file is one stream), and should
|
||||
thus be opened in this state change. When going from the PAUSED back to
|
||||
READY (<classname>GST_STATE_PAUSED_TO_READY</classname>), all
|
||||
READY (<symbol>GST_STATE_PAUSED_TO_READY</symbol>), all
|
||||
stream-specific data should be discarded.
|
||||
</para>
|
||||
<para>
|
||||
<classname>GST_STATE_PLAYING</classname> (from now on referred to as
|
||||
<symbol>GST_STATE_PLAYING</symbol> (from now on referred to as
|
||||
<quote>PLAYING</quote>) is the highest state that an element can be in. It
|
||||
is similar to PAUSED, except that now, data is actually passing over the
|
||||
pipeline. The transition from PAUSED to PLAYING
|
||||
(<classname>GST_STATE_PAUSED_TO_PLAYING</classname>) should be as small
|
||||
(<symbol>GST_STATE_PAUSED_TO_PLAYING</symbol>) should be as small
|
||||
as possible and would ideally cause no delay at all. The same goes for the
|
||||
reverse transition (<classname>GST_STATE_PLAYING_TO_PAUSED</classname>).
|
||||
reverse transition (<symbol>GST_STATE_PLAYING_TO_PAUSED</symbol>).
|
||||
</para>
|
||||
|
||||
<sect1 id="section-statemanage-filters">
|
||||
|
|
|
@ -17,7 +17,8 @@
|
|||
<para>
|
||||
Elements are at the core of &GStreamer;. In the context of plugin
|
||||
development, an <emphasis>element</emphasis> is an object derived from the
|
||||
<classname>GstElement</classname> class. Elements provide some sort of
|
||||
<ulink type="http" url="../../gstreamer/html/GstElement.html"><classname>
|
||||
GstElement</classname></ulink> class. Elements provide some sort of
|
||||
functionality when linked with other elements: For example, a source
|
||||
element provides data to a stream, and a filter element acts on the data
|
||||
in a stream. Without elements, &GStreamer; is just a bunch of conceptual
|
||||
|
@ -56,9 +57,9 @@
|
|||
<para>
|
||||
See the &GstLibRef; for the current implementation details of <ulink
|
||||
type="http"
|
||||
url="../../gstreamer/gstelement.html"><classname>GstElement</classname></ulink>
|
||||
url="../../gstreamer/html/GstElement.html"><classname>GstElement</classname></ulink>
|
||||
and <ulink type="http"
|
||||
url="../../gstreamer/gstreamer-gstplugin.html"><classname>GstPlugin</classname></ulink>.
|
||||
url="../../gstreamer/html/gstreamer-GstPlugin.html"><classname>GstPlugin</classname></ulink>.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
|
@ -97,7 +98,7 @@
|
|||
<para>
|
||||
See the &GstLibRef; for the current implementation details of a <ulink
|
||||
type="http"
|
||||
url="../../gstreamer/gstreamer-gstpad.html"><classname>GstPad</classname></ulink>.
|
||||
url="../../gstreamer/html/GstPad.html"><classname>GstPad</classname></ulink>.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
|
@ -192,9 +193,9 @@
|
|||
<para>
|
||||
See the &GstLibRef; for the current implementation details of a <ulink
|
||||
type="http"
|
||||
url="../../gstreamer/gstreamer-gstdata.html"><classname>GstData</classname></ulink>, <ulink type="http"
|
||||
url="../../gstreamer/gstreamer-gstbuffer.html"><classname>GstBuffer</classname></ulink> and <ulink type="http"
|
||||
url="../../gstreamer/gstreamer-gstevent.html"><classname>GstEvent</classname></ulink>.
|
||||
url="../../gstreamer/html/gstreamer-GstData.html"><classname>GstData</classname></ulink>, <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstBuffer.html"><classname>GstBuffer</classname></ulink> and <ulink type="http"
|
||||
url="../../gstreamer/html/gstreamer-GstEvent.html"><classname>GstEvent</classname></ulink>.
|
||||
</para>
|
||||
|
||||
<sect2 id="sect2-buffer-allocation" xreflabel="Buffer Allocation">
|
||||
|
|
|
@ -67,7 +67,10 @@
|
|||
url="http://developer.gnome.org/doc/API/2.0/gobject/index.html">GObject</ulink>
|
||||
programming. There are several good introductions to the GObject library,
|
||||
including the <emphasis><ulink type="http"
|
||||
url="http://www.gtk.org/tutorial/">GTK+ Tutorial</ulink></emphasis>.
|
||||
url="http://www.gtk.org/tutorial/">GTK+ Tutorial</ulink></emphasis> and
|
||||
the <emphasis><ulink type="http"
|
||||
url="http://www.le-hacker.org/papers/gobject/index.html">Glib Object
|
||||
system</ulink></emphasis>.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
|
|
Loading…
Reference in a new issue