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Original commit message from CVS: * docs/pwg/advanced-clock.xml: * docs/pwg/appendix-porting.xml: * docs/pwg/intro-preface.xml: * docs/pwg/other-base.xml: * docs/pwg/other-manager.xml: * docs/pwg/other-nton.xml: * docs/pwg/other-ntoone.xml: * docs/pwg/other-oneton.xml: * docs/pwg/pwg.xml: Document base classes, update sections of n-to-1 and 1-to-n (muxer, demuxer), remove n-to-n (was never written), fix some code examples and links and update the porting section to include all this.
44 lines
1.6 KiB
XML
44 lines
1.6 KiB
XML
<chapter id="chapter-other-manager" xreflabel="Writing a Manager">
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<title>Writing a Manager</title>
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<para>
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Managers are elements that add a function or unify the function of
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another (series of) element(s). Managers are generally a
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<classname>GstBin</classname> with one or more ghostpads. Inside them
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is/are the actual element(s) that matters. There is several cases where
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this is useful. For example:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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To add support for private events with custom event handling to
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another element.
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</para>
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</listitem>
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<listitem>
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<para>
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To add support for custom pad <function>_query ()</function>
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or <function>_convert ()</function> handling to another element.
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</para>
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</listitem>
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<listitem>
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<para>
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To add custom data handling before or after another element's data
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handler function (generally its <function>_chain ()</function>
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function).
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</para>
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</listitem>
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<listitem>
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<para>
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To embed an element, or a series of elements, into something that
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looks and works like a simple element to the outside world.
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</para>
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</listitem>
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</itemizedlist>
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<para>
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Making a manager is about as simple as it gets. You can derive from a
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<classname>GstBin</classname>, and in most cases, you can embed the
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required elements in the <function>_init ()</function> already, including
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setup of ghostpads. If you need any custom data handlers, you can connect
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signals or embed a second element which you control.
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</para>
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</chapter>
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