<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML
><HEAD
><TITLE
>Using GStreamer</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
REL="HOME"
HREF="index.html"><LINK
REL="PREVIOUS"
TITLE="Getting GStreamer"
HREF="chapter-getting.html"><LINK
REL="NEXT"
TITLE="Troubleshooting GStreamer"
HREF="chapter-troubleshooting.html"></HEAD
><BODY
CLASS="sect1"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="chapter-getting.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="chapter-troubleshooting.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="chapter-using"
>5. Using GStreamer</A
></H1
><DIV
CLASS="qandaset"
><DL
><DT
>5.1. <A
HREF="chapter-using.html#using-getting-started"
>Ok, I've installed GStreamer. What can I do next ?</A
></DT
><DT
>5.2. <A
HREF="chapter-using.html#using-sound"
>Can my system play sound through GStreamer ?</A
></DT
><DT
>5.3. <A
HREF="chapter-using.html#using-gst-inspect"
>How can I see what GStreamer plugins I have on my system ?</A
></DT
><DT
>5.4. <A
HREF="chapter-using.html#using-bugs-where"
>Where should I report bugs ?</A
></DT
><DT
>5.5. <A
HREF="chapter-using.html#using-bugs-how"
>How should I report bugs ?</A
></DT
><DT
>5.6. <A
HREF="chapter-using.html#using-gst-launch"
>How do I use the GStreamer command line interface ?</A
></DT
></DL
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-getting-started"
></A
><B
>5.1. </B
>Ok, I've installed GStreamer. What can I do next ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
First of all, verify that you have a working registry and that you can
inspect them by typing
<PRE
CLASS="programlisting"
> $ gst-inspect fakesrc
</PRE
>
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
<A
HREF="chapter-getting.html"
>how to get GStreamer</A
>
If this fails with any other message, we would appreciate a
<A
HREF="chapter-using.html#using-bugs-where"
>bug report</A
>.
</P
><P
> 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 :
<PRE
CLASS="programlisting"
> $ gst-launch fakesrc num-buffers=3 ! fakesink
</PRE
>
This will print out output that looks similar to this :
<PRE
CLASS="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)
</PRE
>
(Some parts of output have been removed for clarity) If it looks similar, then
GStreamer itself is running correctly.
</P
></DIV
></DIV
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-sound"
></A
><B
>5.2. </B
>Can my system play sound through GStreamer ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
You can test this by trying to play a sine tone. For this, you need to
link the sinesrc plug-in to an output plug-in that matches your hardware.
A (non-complete) list of output plug-ins for audio is
<P
></P
><UL
><LI
><P
>osssink for OSS output</P
></LI
><LI
><P
>esdsink for ESound output</P
></LI
><LI
><P
>artssink for aRTs output</P
></LI
><LI
><P
>alsasink for ALSA output</P
></LI
><LI
><P
>jacksink for JACK output</P
></LI
></UL
>
First of all, run gst-inspect on the output plug-in you want to use to
make sure you have it installed. For example, if you use OSS, run
<PRE
CLASS="programlisting"
> $ gst-inspect osssink
</PRE
>
and see if that prints out a bunch of properties for the plug-in.
</P
><P
> Then try to play the sine tone by running
<PRE
CLASS="programlisting"
> $ gst-launch sinesrc ! osssink
</PRE
>
and see if you hear something. Make sure your volume is turned up,
but also make sure it is not too loud and you are not wearing your headphones.
</P
></DIV
></DIV
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-gst-inspect"
></A
><B
>5.3. </B
>How can I see what GStreamer plugins I have on my system ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
To do this you use the gst-inspect
command-line tool, which comes standard with GStreamer.
Invoked without any arguments,
<PRE
CLASS="programlisting"
> $ gst-inspect
</PRE
>
will print out a listing of installed plugins.
To learn more about a particular plugin, pass its name on the command line.
For example,
<PRE
CLASS="programlisting"
> $ gst-inspect volume
</PRE
>
will give you information about the volume plugin.
</P
><P
> Also, if you install the gst-editor package, you will have a graphical
plugin browser available, gst-inspect-gui.
</P
></DIV
></DIV
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-bugs-where"
></A
><B
>5.4. </B
>Where should I report bugs ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
Bug management is now hosted on GNOME's Bugzilla at
<A
HREF="http://bugzilla.gnome.org"
TARGET="_top"
>http://bugzilla.gnome.org</A
>,
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.
</P
></DIV
></DIV
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-bugs-how"
></A
><B
>5.5. </B
>How should I report bugs ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
When doing a bug report, you should at least describe
<P
></P
><UL
><LI
><P
>your distribution</P
></LI
><LI
><P
> how you installed GStreamer (from cvs, source, packages, which ?)</P
></LI
><LI
><P
>if you installed GStreamer before</P
></LI
></UL
>
</P
><P
> 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
<PRE
CLASS="programlisting"
> myapp --gst-mask=-1 > mask.log 2>&1
gzip mask.log
</PRE
>
(interrupting the program if it doesn't stop by itself)
and attach mask.log.gz to your bug report.
</P
><P
> If the application you are having problems with is segfaulting, then
provide us with the necessary gdb output. See
<A
HREF="chapter-troubleshooting.html#troubleshooting-segfault"
><I
><I
>The GStreamer application I used stops with a segmentation fault. What can
I do ?</I
></I
></A
>
</P
></DIV
></DIV
><DIV
CLASS="qandaentry"
><DIV
CLASS="question"
><P
><A
NAME="using-gst-launch"
></A
><B
>5.6. </B
>How do I use the GStreamer command line interface ?</P
></DIV
><DIV
CLASS="answer"
><P
><B
> </B
>
You access the GStreamer command line interface using the command gst-launch.
To decode an mp3 and play it through OSS, you could use
<PRE
CLASS="programlisting"
> gst-launch filesrc location=thesong.mp3 ! mad ! osssink
</PRE
>.
More examples can be found in the gst-launch man page.
</P
><P
> To automatically detect the right codec in a pipeline, try
<PRE
CLASS="programlisting"
> gst-launch filesrc location=my-random-media-file.mpeg ! spider ! osssink
</PRE
>.
Try replacing osssink with sdlvideosink and see what happens.
</P
><P
> 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
<PRE
CLASS="programlisting"
> gst-launch-ext (filename)
</PRE
>
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.
</P
></DIV
></DIV
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="chapter-getting.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="chapter-troubleshooting.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Getting GStreamer</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
> </TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Troubleshooting GStreamer</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
