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><A
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>16.4. Ghost pads</A
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> You can see from <A
HREF="section-bin-ghostpads.html#section-bin-noghost-img"
>Figure 16-1</A
> how a bin has no pads of its own.
This is where "ghost pads" come into play.
</P
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><B
>Figure 16-1. Visualisation of a <CODE
CLASS="classname"
>GstBin</CODE
> element without ghost pads</B
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> A ghost pad is a pad from some element in the bin that has been promoted to the bin.
This way, the bin also has a pad. The bin becomes just another element with a pad and
you can then use the bin just like any other element. This is a very important feature
for creating custom bins.
</P
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><P
><B
>Figure 16-2. Visualisation of a <CODE
CLASS="classname"
>GstBin</CODE
> element with a ghost pad</B
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> <A
HREF="section-bin-ghostpads.html#section-bin-ghost-img"
>Figure 16-2</A
>
is a representation of a ghost pad. The sink pad of element one is now also a pad
of the bin.
</P
><P
> Ghost pads can actually be added to all <CODE
CLASS="classname"
>GstElement</CODE
>s and not just
<CODE
CLASS="classname"
>GstBin</CODE
>s. Use the following code example to add a ghost pad to a bin:
</P
><PRE
CLASS="programlisting"
> GstElement *bin;
GstElement *element;
element = gst_element_factory_create ("mad", "decoder");
bin = gst_bin_new ("mybin");
gst_bin_add (GST_BIN (bin), element);
gst_element_add_ghost_pad (bin, gst_element_get_pad (element, "sink"), "sink");
</PRE
><P
> In the above example, the bin now also has a pad: the pad called 'sink'
of the given element.
</P
><P
> We can now, for example, link the source pad of a filesrc element
to the bin with:
</P
><PRE
CLASS="programlisting"
> GstElement *filesrc;
filesrc = gst_element_factory_create ("filesrc", "disk_reader");
gst_element_link_pads (filesrc, "src", bin, "sink");
...
</PRE
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