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>20.2. More on MIME Types</A
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>
GStreamer uses MIME types to identify the different types of data
that can be handled by the elements. They are the high level
mechanisms to make sure that everyone is talking about the right
kind of data.
</P
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>
A MIME (Multipurpose Internet Mail Extension) type is a pair of
strings that denote a certain type of data. Examples include:
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> audio/raw : raw audio samples
</P
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> audio/mpeg : MPEG audio
</P
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> video/mpeg : MPEG video
</P
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>
An element must associate a MIME type to its source and sink pads
when it is loaded into the system. GStreamer knows about the
different elements and what type of data they expect and emit.
This allows for very dynamic and extensible element creation as we
will see.
</P
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>
As we have seen in the previous chapter, MIME types are added
to the Capability structure of a pad.
</P
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> <A
HREF="section-factories-mime.html#section-mime-img"
>Figure 20-1</A
> shows the MIME types associated with
each pad from the "hello world" example.
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>Figure 20-1. The Hello world pipeline with MIME types</B
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> We will see how you can create an element based on the MIME types
of its source and sink pads. This way the end-user will have the
ability to choose his/her favorite audio/mpeg decoder without
you even having to care about it.
</P
><P
> The typing of the source and sink pads also makes it possible to
'autoplug' a pipeline. We will have the ability to say: "construct
a pipeline that does an audio/mpeg to audio/raw conversion".
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> The basic GStreamer library does not try to solve all of your
autoplug problems. It leaves the hard decisions to the application
programmer, where they belong.
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