gstreamer/docs/pwg/gst-plugin-writers-guide.xml

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<?xml version='1.0'?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
<!ENTITY % magic-entities SYSTEM "magic">
%magic-entities;
<!ENTITY TITLEPAGE SYSTEM "titlepage.xml">
<!ENTITY INTRO_PREFACE SYSTEM "intro_preface.xml">
<!ENTITY INTRO_BASICS SYSTEM "intro_basics.xml">
<!ENTITY BUILDING_BOILER SYSTEM "building_boiler.xml">
<!ENTITY BUILDING_PADS SYSTEM "building_pads.xml">
<!ENTITY BUILDING_CHAINFN SYSTEM "building_chainfn.xml">
<!ENTITY BUILDING_STATE SYSTEM "building_state.xml">
<!ENTITY BUILDING_PROPS SYSTEM "building_props.xml">
<!ENTITY BUILDING_SIGNALS SYSTEM "building_signals.xml">
<!ENTITY BUILDING_TESTAPP SYSTEM "building_testapp.xml">
<!ENTITY ADVANCED_SCHEDULING SYSTEM "advanced_scheduling.xml">
<!ENTITY ADVANCED_TYPES SYSTEM "advanced_types.xml">
<!ENTITY ADVANCED_REQUEST SYSTEM "advanced_request.xml">
<!ENTITY ADVANCED_CLOCK SYSTEM "advanced_clock.xml">
<!ENTITY ADVANCED_DPARAMS SYSTEM "advanced_dparams.xml">
<!ENTITY ADVANCED_MIDI SYSTEM "advanced_midi.xml">
<!ENTITY OTHER_SOURCE SYSTEM "other_source.xml">
<!ENTITY OTHER_SINK SYSTEM "other_sink.xml">
<!ENTITY OTHER_AUTOPLUGGER SYSTEM "other_autoplugger.xml">
<!ENTITY APPENDIX_CHECKLIST SYSTEM "appendix_checklist.xml">
<!ENTITY APPENDIX_PYTHON SYSTEM "appendix_python.xml">
<!ENTITY GStreamer "<application>GStreamer</application>">
<!ENTITY GstVersion "0.4.1">
<!ENTITY GstAppDevMan "<emphasis>GStreamer Application Development Manual</emphasis>">
<!ENTITY GstLibRef "<emphasis>GStreamer Library Reference</emphasis>">
]>
<book id="book-gst-plugin-writers-guide">
&TITLEPAGE;
<!-- ############# part ############### -->
<part id="part-introduction" xreflabel="Introduction">
<title>Introduction</title>
<partintro>
<para>
&GStreamer; is an exremely powerful and versatile framework for creating
streaming media applications. Many of the virtues of the &GStreamer;
framework come from its modularity: &GStreamer; can seamlessly
incorporate new plugin modules. But because modularity and power often
come at a cost of greater complexity (consider, for example, <ulink
type="http" url="http://www.omg.org/">CORBA</ulink>), writing new
plugins is not always easy.
</para>
<para>
This guide is intended to help you understand the &GStreamer; framework
so you can develop new plugins to extend &GStreamer;'s functionality.
This guide introduces most of the basic plugin writing issues in version
&GstVersion; of &GStreamer;. This guide presents most issues in the
context of an example audio filter plugin written in C. However, the
guide also addresses some issues involved in writing other types of
plugins, and the end of the guide also describes some of the Python
bindings for &GStreamer;.
</para>
</partintro>
&INTRO_PREFACE;
&INTRO_BASICS;
</part>
<!-- ############ part ############# -->
<part id="part-building" xreflabel="Building a Filter">
<title>Building a Filter</title>
<partintro>
<para>
You now have the neccessary concepts to build your first plugin. In this
part of the guide, you will learn how to apply these concepts to write a
simple audio filter plugin. The previous parts of the guide have
contained no explicit example code, perhaps making things a bit abstract
and difficult to understand. In contrast, this section will present both
applications and code by following the development of an example audio
filter plugin called <quote>ExampleFilter</quote>.
</para>
<para>
The example filter will begin with a single input pad and a single
output pad. The filter will, at first, simply pass data through without
modification. But by the end of this part of the guide, you will learn
to add some more interesting functionality, including properties and
signal handlers. And after reading the next part of the guide, <xref
linkend="part-advanced"/>, you will be able to add even more
functionality to your plugins.
</para>
<para>
The example code used in this part of the guide can be found in
<filename class="directory">examples/pwg/examplefilter/</filename> in
your &GStreamer; directory.
</para>
</partintro>
&BUILDING_BOILER;
&BUILDING_PADS;
&BUILDING_CHAINFN;
&BUILDING_STATE;
&BUILDING_PROPS;
&BUILDING_SIGNALS;
&BUILDING_TESTAPP;
</part>
<!-- ############ part ############# -->
<part id="part-advanced" xreflabel="Advanced Filter Concepts">
<title>Advanced Filter Concepts</title>
<partintro>
<para>
</para>
</partintro>
&ADVANCED_SCHEDULING;
&ADVANCED_TYPES;
&ADVANCED_REQUEST;
&ADVANCED_CLOCK;
&ADVANCED_DPARAMS;
&ADVANCED_MIDI;
</part>
<!-- ############ part ############# -->
<part id="part-other" xreflabel="Other Element Types">
<title>Other Element Types</title>
<partintro>
<para>
</para>
</partintro>
&OTHER_SOURCE;
&OTHER_SINK;
&OTHER_AUTOPLUGGER;
</part>
<!-- ############ part ############# -->
<part id="part-appendix" xreflabel="Appendices">
<title>Appendices</title>
<partintro>
<para>
</para>
</partintro>
&APPENDIX_CHECKLIST;
&APPENDIX_PYTHON;
</part>
</book>