--- /dev/null
+<chapter id="cha-clocks">
+ <title>Clocks in GStreamer</title>
+ <para>
+ </para>
+</chapter>
--- /dev/null
+<chapter id="cha-scheduler">
+ <title>Understanding schedulers</title>
+ <para>
+ </para>
+
+</chapter>
+++ /dev/null
-<chapter id="cha-advanced">
- <title>Threads</title>
- <para>
- The small application we created in the previous chapter used the
- concept of a factory to create the elements. In this chapter we will
- show you how to use the factory concepts.
- </para>
-
- <sect1>
- <title>The problems with the helloworld example</title>
- <para>
- If we take a look at how the elements were created in the previous
- example we used a rather crude mechanism:
- </para>
-
- <programlisting>
- ...
- /* now it's time to get the parser */
- parse = gst_elementfactory_make("mp3parse","parse");
- decoder = gst_elementfactory_make("mpg123","decoder");
- ...
- </programlisting>
-
- <para>
- While this mechanism is quite effective it also has one big problems:
- The elements are created base on their name. Indeed, we create an
- element mpg123 by explicitly stating the mpg123 elements name.
- Our little program therefore always uses the mpg123 decoder element
- to decode the MP3 audio stream, even if there are 3 other MP3 decoders
- in the system. We will see how we can use a more general way to create
- an MP3 decoder element.
- </para>
- <para>
- We have to introduce the concept of MIME types added to the source and
- sink pads.
- </para>
- </sect1>
-
- <sect1>
- <title>MIME Types</title>
- <para>
- GStreamer uses MIME types to indentify 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.
- </para>
- <para>
- A MIME (Multipurpose Internet Mail Extension) types are a set of
- string that donote a certain type of data. examples include:
- <itemizedlist>
- <listitem>
- <para>
- audio/raw : raw audio samples
- </para>
- </listitem>
- <listitem>
- <para>
- audio/mpeg : mpeg audio
- </para>
- </listitem>
- <listitem>
- <para>
- video/mpeg : mpeg video
- </para>
- </listitem>
- </itemizedlist>
- </para>
- <para>
- 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.
- </para>
-
- <para>
- In our helloworld example the elements we constructed would have the
- following MIME types associated with their source and sink pads:
- </para>
- <para>
- 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.
- </para>
- <para>
- The typing of the source and sink pads also makes it possible to
- 'autoplug' a pipeline. We will have the ability to say: "construct
- me a pipeline that does an audio/mpeg to audio/raw conversion".
- </para>
- <note>
- <para>
- 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.
- </para>
- </note>
-
- </sect1>
-
- <sect1>
- <title>GStreamer types</title>
- <para>
- GStreamer assigns a unique number to all registered MIME types. It
- also maintains a list of all elements that either uses this type
- as a source or as a sink. GStreamer also keeps a reference to
- a function that can be used to determine if a given buffer is of
- the given MIME type.
- </para>
- <para>
- There is also an association between a MIME type and a file
- extension.
- </para>
- <para>
- The type information is maintained in a list of
- <classname>GstType</classname>. The definition of a
- <classname>GstType</classname> is like:
- </para>
- <programlisting>
-typedef gboolean (*GstTypeFindFunc) (GstBuffer *buf,gpointer *priv);
-
-typedef struct _GstType GstType;
-
-struct _GstType {
- guint16 id; /* type id (assigned) */
-
- gchar *mime; /* MIME type */
- gchar *exts; /* space-delimited list of extensions */
-
- GstTypeFindFunc typefindfunc; /* typefind function */
-
- GList *srcs; /* list of src objects for this type */
- GList *sinks; /* list of sink objects for type */
-};
- </programlisting>
- <para>
- All operations on <classname>GstType</classname> occur via their
- <classname>guint16 id</classname> numbers, with <classname>GstType</classname>
- structure private to the GStreamer library.
- </para>
-
- <sect2>
- <title>MIME type to id conversion</title>
-
- <para>
- We can obtain the id for a given MIME type
- with the following piece of code:
- </para>
- <programlisting>
- guint16 id;
-
- id = gst_type_find_by_mime("audio/mpeg");
- </programlisting>
- <para>
- This function will return 0 if the type was not known.
- </para>
- </sect2>
-
- <sect2>
- <title>id to <classname>GstType</classname> conversion</title>
- <para>
- We can obtain the <classname>GstType</classname> for a given id
- with the following piece of code:
- </para>
- <programlisting>
- GstType *type;
-
- type = gst_type_find_by_id(id);
- </programlisting>
- <para>
- This function will return NULL if the id was associated with
- any known <classname>GstType</classname>
- </para>
- </sect2>
-
- <sect2>
- <title>extension to id conversion</title>
- <para>
- We can obtain the id for a given file extension
- with the following piece of code:
- </para>
- <programlisting>
- guint16 id;
-
- id = gst_type_find_by_ext(".mp3");
- </programlisting>
- <para>
- This function will return 0 if the extension was not known.
- </para>
- </sect2>
-
- <sect2>
- <title>id to <classname>GstElementFactory</classname> conversion</title>
- <para>
- When we have obtained a given type id using one of the above methods,
- we can obtain a list of all the elements that operate on this MIME
- type or extension.
- </para>
- <para>
- Obtain a list of all the elements that use this id as source with:
- </para>
- <programlisting>
- GList *list;
-
- list = gst_type_gst_srcs(id);
- </programlisting>
-
- <para>
- Obtain a list of all the elements that use this id as sink with:
- </para>
- <programlisting>
- GList *list;
-
- list = gst_type_gst_sinks(id);
- </programlisting>
- <para>
- When you have a list of elements, you can simply take the first
- element of the list to obtain an appropriate element.
- </para>
- <note>
- <para>
- As you can see, there might be a multitude of elements that
- are able to operate on audio/raw types. some might include:
- <itemizedlist>
- <listitem>
- <para>
- an MP3 audio encoder.
- </para>
- </listitem>
- <listitem>
- <para>
- an audio sink.
- </para>
- </listitem>
- <listitem>
- <para>
- an audio resampler.
- </para>
- </listitem>
- <listitem>
- <para>
- a spectrum filter.
- </para>
- </listitem>
- </itemizedlist>
- Depending on the application, you might want to use a different
- element. This is why GStreamer leaves that decision up to the
- application programmer.
- </para>
- </note>
-
- </sect2>
-
- <sect2>
- <title>id to id path detection</title>
- <para>
- You can obtain a <classname>GList</classname> of elements that
- will transform the source id into the destination id.
- </para>
- <programlisting>
- GList *list;
-
- list = gst_type_gst_sink_to_src(sourceid, sinkid);
- </programlisting>
- <para>
- This piece of code will give you the elements needed to construct
- a path from sourceid to sinkid. This function is mainly used in
- autoplugging the pipeline.
- </para>
- </sect2>
- </sect1>
-
- <sect1>
- <title>creating elements with the factory</title>
- <para>
- In the previous section we described how you could obtain
- an element factory using MIME types. Once the factory has been
- obtained, you can create an element using:
- </para>
- <programlisting>
- GstElementFactory *factory;
- GstElement *element;
-
- // obtain the factory
- factory = ...
-
- element = gst_elementfactory_create(factory, "name");
- </programlisting>
- <para>
- This way, you do not have to create elements by name which
- allows the end-user to select the elements he/she prefers for the
- given MIME types.
- </para>
- </sect1>
-
- <sect1>
- <title>GStreamer basic types</title>
- <para>
- GStreamer only has two builtin types:
- </para>
- <itemizedlist>
- <listitem>
- <para>
- audio/raw : raw audio samples
- </para>
- </listitem>
- <listitem>
- <para>
- video/raw and image/raw : raw video data
- </para>
- </listitem>
- </itemizedlist>
- <para>
- All other MIME types are maintained by the plugin elements.
- </para>
-
- </sect1>
-</chapter>
</para>
<sect1>
- <title><command>gstreamer-config</command></title>
- <para>
- <command>gstreamer-config</command> is a script to get information about the installed
- version of <application>GStreamer</application>.
- This program "knows" what compiler switches are needed to compile programs that use
- <application>GStreamer</application>.
- </para>
-
- <para>
- <command>gstreamer-config</command> accepts the following options:
-
- <itemizedlist>
- <listitem>
- <para>
- <option>--version</option> Print the currently installed version of
- <application>GStreamer</application> on the standard output.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--libs</option> Print the linker flags that are necessary to link a
- <application>GStreamer</application> program.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--cflags</option> Print the compiler flags that are necessary to compile a
- <application>GStreamer</application> program.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--prefix=<replaceable>PREFIX</replaceable></option>
- If specified, use <replaceable>PREFIX</replaceable> instead of the installation
- prefix that <application>GStreamer</application> was built with when computing the
- output for the <option>--cflags</option> and <option>--libs</option> options.
- This option is also used for the exec prefix if
- <option>--exec-prefix</option> was not specified. This option must be specified before any
- <option>--libs</option> or <option>--cflags</option> options.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--exec-prefix=<replaceable>PREFIX</replaceable></option>
- If specified, use <replaceable>PREFIX</replaceable> instead of the installation exec
- prefix that <application>GStreamer</application> was built with when computing the
- output for the <option>--cflags</option> and <option>--libs</option> options. This option must be
- specified before any <option>--libs</option> or <option>--cflags</option>
- options.
- </para>
- </listitem>
- </itemizedlist>
- </para>
- <para>
- A simple <filename>Makefile</filename> will contain something like:
- <programlisting>
-CC = gcc
-
-helloworld2: helloworld2.c
- $(CC) -Wall `gstreamer-config --cflags --libs` helloworld2.c -o helloworld2
-
-clean:
- rm -f *.o helloworld2
- </programlisting>
- </para>
- </sect1>
-
- <sect1>
<title><command>gstreamer-register</command></title>
<para>
<command>gstreamer-register</command> is used to rebuild the database of plugins.
+pre.programlisting {
+ background: #E8E8FF;
+}
int
main (int argc, char *argv[])
{
- GstElement *pipeline, *filesrc, *parse, *decoder, *audiosink;
+ GstElement *pipeline, *filesrc, *decoder, *audiosink;
gst_init(&argc, &argv);
filesrc = gst_elementfactory_make ("filesrc", "disk_source");
g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);
- /* now it's time to get the parser */
- parse = gst_elementfactory_make ("mp3parse", "parse");
- decoder = gst_elementfactory_make ("mpg123", "decoder");
+ /* now it's time to get the decoder */
+ decoder = gst_elementfactory_make ("mad", "decoder");
/* and an audio sink */
audiosink = gst_elementfactory_make ("osssink", "play_audio");
/* add objects to the main pipeline */
gst_bin_add (GST_BIN (pipeline), filesrc);
- gst_bin_add (GST_BIN (pipeline), parse);
gst_bin_add (GST_BIN (pipeline), decoder);
gst_bin_add (GST_BIN (pipeline), audiosink);
/* connect src to sink */
gst_pad_connect (gst_element_get_pad (filesrc, "src"),
- gst_element_get_pad (parse, "sink"));
- gst_pad_connect (gst_element_get_pad (parse, "src"),
gst_element_get_pad (decoder, "sink"));
gst_pad_connect (gst_element_get_pad (decoder, "src"),
gst_element_get_pad (audiosink, "sink"));
/* we don't need a reference to these objects anymore */
gst_object_unref (GST_OBJECT (audiosink));
- gst_object_unref (GST_OBJECT (parse));
gst_object_unref (GST_OBJECT (decoder));
gst_object_unref (GST_OBJECT (filesrc));
gst_object_unref (GST_OBJECT (pipeline));
</programlisting>
<para>
- We are going to create 4 elements and one pipeline. Since all objects are
+ We are going to create 3 elements and one pipeline. Since all objects are
in fact elements, we can define them as:
</para>
<programlisting>
...
- GstElement *pipeline, *filesrc, *parse, *decoder, *audiosink;
+ GstElement *pipeline, *filesrc, *decoder, *audiosink;
...
</programlisting>
</note>
<para>
- We now create the MP3 decoder element. <application>GStreamer</application> requires you
- to put a parser in front of the decoder. This parser will
- cut the raw data from the disk source into MP3 frames
- suitable for the decoder. In the advanced concepts chapter we will
- see how this can be avoided.
+ 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 parser */
- parse = gst_elementfactory_make ("mp3parse", "parse");
- decoder = gst_elementfactory_make ("mpg123", "decoder");
+ decoder = gst_elementfactory_make ("mad", "decoder");
</programlisting>
<para>
gst_elementfactory_make() takes two arguments: a string that will
<programlisting>
/* add objects to the main pipeline */
gst_bin_add (GST_BIN (pipeline), filesrc);
- gst_bin_add (GST_BIN (pipeline), parse);
gst_bin_add (GST_BIN (pipeline), decoder);
gst_bin_add (GST_BIN (pipeline), audiosink);
</programlisting>
<programlisting>
/* connect src to sink */
gst_pad_connect (gst_element_get_pad (filesrc, "src"),
- gst_element_get_pad (parse, "sink"));
- gst_pad_connect (gst_element_get_pad (parse, "src"),
gst_element_get_pad (decoder, "sink"));
gst_pad_connect (gst_element_get_pad (decoder, "src"),
gst_element_get_pad (audiosink, "sink"));
</programlisting>
<note>
<para>
- <application>GStreamer</application> will take care of the READY and PAUSED state for y
- ou when going from NULL to PLAYING.
+ <application>GStreamer</application> will take care of the READY and PAUSED state for
+ you when going from NULL to PLAYING.
</para>
</note>
To compile the helloworld example, use:
</para>
<programlisting>
- gcc -Wall `gstreamer-config --cflags --libs` helloworld.c \
+ gcc -Wall `pkg-config gstreamer --cflags --libs` helloworld.c \
-o helloworld
</programlisting>
<para>
- This uses the program gstreamer-config, which comes with <application>GStreamer</application>. This program "knows"
- what compiler switches are needed to compile programs that use <application>GStreamer</application>.
- gstreamer-config --cflags will output a list of include
- directories for the compiler to look in, and gstreamer-config --libs will output the
- list of libraries for the compiler to link with and the directories to find them
- in.
+ 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):
into the pipeline is not that hard to do. The most important thing is
that you can reuse allready existing elements.
</para>
-
-
</sect1>
</chapter>
--- /dev/null
+<chapter id="cha-clocks">
+ <title>Clocks in GStreamer</title>
+ <para>
+ </para>
+</chapter>
audiocard. We will use this simple graph to construct an mpeg player later
in this manual.
</para>
- <para>
- You can connect two pads with:
- </para>
- <programlisting>
+
+ <sect1 id="sec-conn-basic">
+ <title>Making simple connections</title>
+ <para>
+ You can connect two pads with:
+ </para>
+ <programlisting>
GstPad *srcpad, *sinkpad;
srcpad = gst_element_get_pad (element1, "src");
// and disconnect them
gst_pad_disconnect (srcpad, sinkpad);
- </programlisting>
- <para>
- A convenient shortcut for the above code is done with the gst_element_connect ()
- function:
- </para>
+ </programlisting>
+ A convenient shortcut for the above code is done with the gst_element_connect ()
+ function:
+ </para>
<programlisting>
// connect them
// and disconnect them
gst_element_disconnect (element1, "src", element2, "sink");
- </programlisting>
- <para>
- You can query if a pad is connected with GST_PAD_IS_CONNECTED (pad).
- </para>
- <para>
- To query for the <classname>GstPad</classname> this srcpad is connected to, use
- gst_pad_get_peer (srcpad).
- </para>
+ </programlisting>
+ <para>
+ You can query if a pad is connected with GST_PAD_IS_CONNECTED (pad).
+ </para>
+ <para>
+ To query for the <classname>GstPad</classname> this srcpad is connected to, use
+ gst_pad_get_peer (srcpad).
+ </para>
+ </sect1>
+
+ <sect1 id="sec-conn-filtered">
+ <title>Making filtered connections</title>
+ <para>
+ You can also force a specific media type on the connection by using gst_pad_connect_filtered ()
+ and gst_element_connect_filtered ().
+ </para>
+ </sect1>
</chapter>
<!ENTITY THREADS SYSTEM "threads.xml">
<!ENTITY QUEUES SYSTEM "queues.xml">
<!ENTITY COTHREADS SYSTEM "cothreads.xml">
+<!ENTITY SCHEDULERS SYSTEM "schedulers.xml">
+<!ENTITY CLOCKS SYSTEM "clocks.xml">
<!ENTITY DYNAMIC SYSTEM "dynamic.xml">
<!ENTITY TYPEDETECTION SYSTEM "typedetection.xml">
<!ENTITY UTILITY SYSTEM "utility.xml">
&COTHREADS;
+ &SCHEDULERS;
+
+ &CLOCKS;
+
&DYNAMIC;
&TYPEDETECTION;
2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
1 1 1.00 90.00 120.00
4050 3750 4575 3750
+2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
+ 1 1 1.00 90.00 120.00
+ 6525 3750 7125 3750
2 2 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
4575 2775 6525 2775 6525 4425 4575 4425 4575 2775
2 2 0 1 0 6 50 0 20 0.000 0 0 -1 0 0 5
4575 3600 5325 3600 5325 4125 4575 4125 4575 3600
2 2 0 1 0 6 50 0 20 0.000 0 0 -1 0 0 5
5775 3600 6525 3600 6525 4125 5775 4125 5775 3600
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
- 1 1 1.00 90.00 120.00
- 6525 3750 7125 3750
2 2 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
7125 2775 9075 2775 9075 4425 7125 4425 7125 2775
2 2 0 1 0 6 50 0 20 0.000 0 0 -1 0 0 5
7125 3600 7875 3600 7875 4125 7125 4125 7125 3600
-2 2 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
- 9600 2775 11550 2775 11550 4425 9600 4425 9600 2775
-2 2 0 1 0 6 50 0 20 0.000 0 0 -1 0 0 5
- 8325 3600 9075 3600 9075 4125 8325 4125 8325 3600
-2 2 0 1 0 6 50 0 20 0.000 0 0 -1 0 0 5
- 9600 3600 10350 3600 10350 4125 9600 4125 9600 3600
-2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
- 1 1 1.00 90.00 120.00
- 9075 3750 9600 3750
2 2 0 1 0 7 100 0 -1 0.000 0 0 -1 0 0 5
- 1950 1950 11700 1950 11700 4800 1950 4800 1950 1950
-4 0 0 50 0 16 12 0.0000 4 135 255 2175 2250 bin\001
+ 1950 1950 9375 1950 9375 4800 1950 4800 1950 1950
+4 0 0 50 0 16 12 0.0000 4 180 660 2175 2250 pipeline\001
4 0 0 50 0 16 12 0.0000 4 105 255 3525 3975 src\001
+4 0 0 50 0 16 12 0.0000 4 165 1005 2250 3075 disk_source\001
4 0 0 50 0 16 12 0.0000 4 135 330 4725 3975 sink\001
-4 0 0 50 0 16 12 0.0000 4 105 255 6075 3975 src\001
+4 0 0 50 0 16 12 0.0000 4 105 255 6000 3975 src\001
+4 0 0 50 0 16 12 0.0000 4 135 690 4725 3075 decoder\001
4 0 0 50 0 16 12 0.0000 4 135 330 7350 3975 sink\001
-4 0 0 50 0 16 12 0.0000 4 105 255 8625 3975 src\001
-4 0 0 50 0 16 12 0.0000 4 135 330 9750 3975 sink\001
-4 0 0 50 0 16 12 0.0000 4 165 1005 2250 3075 disk_source\001
-4 0 0 50 0 16 12 0.0000 4 150 465 4725 3075 parse\001
-4 0 0 50 0 16 12 0.0000 4 135 690 7275 3075 decoder\001
-4 0 0 50 0 16 12 0.0000 4 180 930 9750 3075 play_audio\001
+4 0 0 50 0 16 12 0.0000 4 180 930 7275 3075 play_audio\001
int
main (int argc, char *argv[])
{
- GstElement *pipeline, *filesrc, *parse, *decoder, *audiosink;
+ GstElement *pipeline, *filesrc, *decoder, *audiosink;
gst_init(&argc, &argv);
filesrc = gst_elementfactory_make ("filesrc", "disk_source");
g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);
- /* now it's time to get the parser */
- parse = gst_elementfactory_make ("mp3parse", "parse");
- decoder = gst_elementfactory_make ("mpg123", "decoder");
+ /* now it's time to get the decoder */
+ decoder = gst_elementfactory_make ("mad", "decoder");
/* and an audio sink */
audiosink = gst_elementfactory_make ("osssink", "play_audio");
/* add objects to the main pipeline */
gst_bin_add (GST_BIN (pipeline), filesrc);
- gst_bin_add (GST_BIN (pipeline), parse);
gst_bin_add (GST_BIN (pipeline), decoder);
gst_bin_add (GST_BIN (pipeline), audiosink);
/* connect src to sink */
gst_pad_connect (gst_element_get_pad (filesrc, "src"),
- gst_element_get_pad (parse, "sink"));
- gst_pad_connect (gst_element_get_pad (parse, "src"),
gst_element_get_pad (decoder, "sink"));
gst_pad_connect (gst_element_get_pad (decoder, "src"),
gst_element_get_pad (audiosink, "sink"));
/* we don't need a reference to these objects anymore */
gst_object_unref (GST_OBJECT (audiosink));
- gst_object_unref (GST_OBJECT (parse));
gst_object_unref (GST_OBJECT (decoder));
gst_object_unref (GST_OBJECT (filesrc));
gst_object_unref (GST_OBJECT (pipeline));
</programlisting>
<para>
- We are going to create 4 elements and one pipeline. Since all objects are
+ We are going to create 3 elements and one pipeline. Since all objects are
in fact elements, we can define them as:
</para>
<programlisting>
...
- GstElement *pipeline, *filesrc, *parse, *decoder, *audiosink;
+ GstElement *pipeline, *filesrc, *decoder, *audiosink;
...
</programlisting>
</note>
<para>
- We now create the MP3 decoder element. <application>GStreamer</application> requires you
- to put a parser in front of the decoder. This parser will
- cut the raw data from the disk source into MP3 frames
- suitable for the decoder. In the advanced concepts chapter we will
- see how this can be avoided.
+ 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 parser */
- parse = gst_elementfactory_make ("mp3parse", "parse");
- decoder = gst_elementfactory_make ("mpg123", "decoder");
+ decoder = gst_elementfactory_make ("mad", "decoder");
</programlisting>
<para>
gst_elementfactory_make() takes two arguments: a string that will
<programlisting>
/* add objects to the main pipeline */
gst_bin_add (GST_BIN (pipeline), filesrc);
- gst_bin_add (GST_BIN (pipeline), parse);
gst_bin_add (GST_BIN (pipeline), decoder);
gst_bin_add (GST_BIN (pipeline), audiosink);
</programlisting>
<programlisting>
/* connect src to sink */
gst_pad_connect (gst_element_get_pad (filesrc, "src"),
- gst_element_get_pad (parse, "sink"));
- gst_pad_connect (gst_element_get_pad (parse, "src"),
gst_element_get_pad (decoder, "sink"));
gst_pad_connect (gst_element_get_pad (decoder, "src"),
gst_element_get_pad (audiosink, "sink"));
</programlisting>
<note>
<para>
- <application>GStreamer</application> will take care of the READY and PAUSED state for y
- ou when going from NULL to PLAYING.
+ <application>GStreamer</application> will take care of the READY and PAUSED state for
+ you when going from NULL to PLAYING.
</para>
</note>
To compile the helloworld example, use:
</para>
<programlisting>
- gcc -Wall `gstreamer-config --cflags --libs` helloworld.c \
+ gcc -Wall `pkg-config gstreamer --cflags --libs` helloworld.c \
-o helloworld
</programlisting>
<para>
- This uses the program gstreamer-config, which comes with <application>GStreamer</application>. This program "knows"
- what compiler switches are needed to compile programs that use <application>GStreamer</application>.
- gstreamer-config --cflags will output a list of include
- directories for the compiler to look in, and gstreamer-config --libs will output the
- list of libraries for the compiler to link with and the directories to find them
- in.
+ 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):
into the pipeline is not that hard to do. The most important thing is
that you can reuse allready existing elements.
</para>
-
-
</sect1>
</chapter>
No provisions have been made for emerging technologies such as
the GNOME object embedding using BONOBO.
</para>
+ <para>
+ While the GStreamer core does not use network transparent technologies
+ at the lowest level, it shouldn't be hard to create a wrapper around the
+ core components.
+ </para>
</sect2>
<sect2 id="sec-motivation-catchup">
No provisions have been made for emerging technologies such as
the GNOME object embedding using BONOBO.
</para>
+ <para>
+ While the GStreamer core does not use network transparent technologies
+ at the lowest level, it shouldn't be hard to create a wrapper around the
+ core components.
+ </para>
</sect2>
<sect2 id="sec-motivation-catchup">
</para>
<sect1>
- <title><command>gstreamer-config</command></title>
- <para>
- <command>gstreamer-config</command> is a script to get information about the installed
- version of <application>GStreamer</application>.
- This program "knows" what compiler switches are needed to compile programs that use
- <application>GStreamer</application>.
- </para>
-
- <para>
- <command>gstreamer-config</command> accepts the following options:
-
- <itemizedlist>
- <listitem>
- <para>
- <option>--version</option> Print the currently installed version of
- <application>GStreamer</application> on the standard output.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--libs</option> Print the linker flags that are necessary to link a
- <application>GStreamer</application> program.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--cflags</option> Print the compiler flags that are necessary to compile a
- <application>GStreamer</application> program.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--prefix=<replaceable>PREFIX</replaceable></option>
- If specified, use <replaceable>PREFIX</replaceable> instead of the installation
- prefix that <application>GStreamer</application> was built with when computing the
- output for the <option>--cflags</option> and <option>--libs</option> options.
- This option is also used for the exec prefix if
- <option>--exec-prefix</option> was not specified. This option must be specified before any
- <option>--libs</option> or <option>--cflags</option> options.
- </para>
- </listitem>
- <listitem>
- <para>
- <option>--exec-prefix=<replaceable>PREFIX</replaceable></option>
- If specified, use <replaceable>PREFIX</replaceable> instead of the installation exec
- prefix that <application>GStreamer</application> was built with when computing the
- output for the <option>--cflags</option> and <option>--libs</option> options. This option must be
- specified before any <option>--libs</option> or <option>--cflags</option>
- options.
- </para>
- </listitem>
- </itemizedlist>
- </para>
- <para>
- A simple <filename>Makefile</filename> will contain something like:
- <programlisting>
-CC = gcc
-
-helloworld2: helloworld2.c
- $(CC) -Wall `gstreamer-config --cflags --libs` helloworld2.c -o helloworld2
-
-clean:
- rm -f *.o helloworld2
- </programlisting>
- </para>
- </sect1>
-
- <sect1>
<title><command>gstreamer-register</command></title>
<para>
<command>gstreamer-register</command> is used to rebuild the database of plugins.
--- /dev/null
+<chapter id="cha-scheduler">
+ <title>Understanding schedulers</title>
+ <para>
+ </para>
+
+</chapter>
provides some easy wrappers for this common operation.
</para>
<para>
- Instead of writing the following Gtk+ code to query the GTK_STRING value
+ Instead of writing the following glib code to query the GTK_STRING value
of an object:
</para>
<programlisting>
projects / platform / upstream / gstreamer.git / commitdiff