gstreamer/docs/faq/using.xml

<sect1 id="chapter-using">
  <title id="title-using">Using GStreamer</title>
  <qandaset>

    <qandaentry>
      <question id="using-getting-started">
        <para>Ok, I've installed GStreamer.  What can I do next ?</para>
      </question>

      <answer>
        <para>
First of all, verify that you have a working registry and that you can
inspect them by typing
<programlisting>
$ gst-inspect fakesrc
</programlisting>
This should print out a bunch of information about this particular element.
If this tells you that there is "no such element or plugin", you haven't
installed GStreamer correctly.  Please check
<link linkend="chapter-getting">how to get GStreamer</link>
If this fails with any other message, we would appreciate a
<link linkend="using-bugs-where">bug report</link>.
        </para>
        <para>
It's time to try out a few things.  Start with gst-launch and two plug-ins
that you really should have : fakesrc and fakesink.  They do nothing except
pass empty buffers. Type this at the command-line :
<programlisting>
$ gst-launch fakesrc num-buffers=3 ! fakesink
</programlisting>
This will print out output that looks similar to this :
<programlisting>
RUNNING pipeline
fakesrc0: last-message = "get      ******* (fakesrc0:src)gt; (0 bytes, 0) 0x8057510"
fakesink0: last-message = "chain   ******* (fakesink0:sink)lt; (0 bytes, 0) 0x8057510"
fakesrc0: last-message = "get      ******* (fakesrc0:src)gt; (0 bytes, 1) 0x8057510"
fakesink0: last-message = "chain   ******* (fakesink0:sink)lt; (0 bytes, 1) 0x8057510"
fakesrc0: last-message = "get      ******* (fakesrc0:src)gt; (0 bytes, 2) 0x8057510"
fakesink0: last-message = "chain   ******* (fakesink0:sink)lt; (0 bytes, 2) 0x8057510"
execution ended after 5 iterations (sum 301479000 ns, average 60295800 ns, min 3000 ns, max 105482000 ns)
</programlisting>
(Some parts of output have been removed for clarity)  If it looks similar, then
GStreamer itself is running correctly.
        </para>
        <para>
After this, you might want to try and see if GStreamer can play audio on your
system.  You need to combine two plug-ins for this test : sinesrc (which
produces a pure tone) and an audio output plug-in.  You should choose one
that matches your current sound output and you should make sure you have
it installed.
        </para>
   
      </answer>
    </qandaentry>

    <qandaentry>
      <question id="using-gst-inspect">
        <para>How can I see what GStreamer plugins I have on my system ?</para>
      </question>

      <answer>
        <para>
To do this you use the gst-inspect
command-line tool, which comes standard with GStreamer.
Invoked without any arguments,
<programlisting>
$ gst-inspect
</programlisting>
will print out a listing of installed plugins.
To learn more about a particular plugin, pass its name on the command line. 
For example,
<programlisting>
$ gst-inspect volume
</programlisting>
will give you information about the volume plugin.
        </para>
        <para>
Also, if you install the gst-editor package, you will have a graphical 
plugin browser available, gst-inspect-gui.
        </para>
      </answer>
    </qandaentry>

    <qandaentry>
      <question id="using-bugs-where">
        <para>Where should I report bugs ?</para>
      </question>

      <answer>
        <para>
Bug management is now hosted on GNOME's Bugzilla at
<ulink url="http://bugzilla.gnome.org">http://bugzilla.gnome.org</ulink>,
under the product GStreamer. 
Using bugzilla you can view past bug history, report new bugs, etc.
Bugzilla requires you to make an account here, which might seem cumbersome,
but allows us to at least have a chance at contacting you for further
information, as we will most likely have to.
        </para>
      </answer>
    </qandaentry>


    <qandaentry>
      <question id="using-bugs-how">
        <para>How should I report bugs ?</para>
      </question>

      <answer>
        <para>
When doing a bug report, you should at least describe
<itemizedlist>
<listitem>your distribution</listitem>
<listitem>
how you installed GStreamer (from cvs, source, packages, which ?)</listitem>
<listitem>if you installed GStreamer before</listitem>
</itemizedlist>
        </para>
        <para>
It also is useful for us if you attach output of
the gst-feedback command to your bug report.
If you're having problem with a specific application (either one of ours,
somebody else's, or your own), please also provide a log of gst-mask by
running
<programlisting>
myapp --gst-mask=-1 > mask.log 2>&amp;1
gzip mask.log
</programlisting>
(interrupting the program if it doesn't stop by itself)
and attach mask.log.gz to your bug report.
        </para>
        <para>
If the application you are having problems with is segfaulting, then
provide us with the necessary gdb output.  See
<xref linkend="troubleshooting-segfault" endterm="troubleshooting-segfault"/>
        </para>
      </answer>
    </qandaentry>

    <qandaentry>
      <question id="using-gst-launch">
        <para>How do I use the GStreamer command line interface ?</para>
      </question>
      <answer>
        <para>
You access the GStreamer command line interface using the command gst-launch.
To decode an mp3 and play it through OSS, you could use
<programlisting>
gst-launch filesrc location=thesong.mp3 ! mad ! osssink
</programlisting>.
More examples can be found in the gst-launch man page.
        </para>
        <para>
To automatically detect the right codec in a pipeline, try 
<programlisting>
gst-launch filesrc location=my-random-media-file.mpeg ! spider ! osssink
</programlisting>.
Try replacing osssink with sdlvideosink and see what happens.
        </para>
        <para>
We also have a simple tool called gst-launch-ext used for debugging,
which has predefined pipelines for you. This means you can just write
<programlisting>
gst-launch-ext (filename)
</programlisting>
and it will play the file if the extension is supported.  Note that no effort
has been made for uninterrupted synchronized playback using this tool.
        </para>
      </answer>
    </qandaentry>
  </qandaset>
</sect1>