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Original commit message from CVS: * docs/faq/troubleshooting.xml: Mention gst-register in the FAQ (fixes 139045).
194 lines
6.7 KiB
XML
194 lines
6.7 KiB
XML
<sect1 id="chapter-troubleshooting">
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<title id="title-troubleshooting">Troubleshooting GStreamer</title>
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<qandaset>
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<qandaentry>
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<question id="troubleshooting-undefined-behaviour">
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<para>
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My GStreamer-based application crashes on startup with errors about unfound
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schedulers on the command-line. I get undefined behaviour as soon as any
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GStreamer element is being initialized.
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</para>
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</question>
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<answer>
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<para>
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Your registry is probably missing, or it is outdated (i.e. not updated after
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a recent upgrade). Fix this by running gst-register yourself:
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<programlisting>
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gst-register
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</programlisting>
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In the worst case, you might have to run it both as user and as root.
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</para>
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<para>
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Note that package managers are suggested to run this automatically during the
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post-installation. Our RPMs and Debian packages do just that.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="troubleshooting-missing-plug-in">
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<para>
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Some application is telling me that I am missing a plug-in. What do I do ?
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</para>
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</question>
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<answer>
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<para>
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Well, start by checking if you really are missing the plug-in.
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<programlisting>
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gst-inspect (plug-in)
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</programlisting>
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and replace (plug-in) with the plug-in you think is missing.
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If this doesn't return any result, then you either don't have it or your
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registry cannot find it.
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</para>
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<para>
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If you're not sure either way, then chances are good that you don't have
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it. You should get the plug-in and run gst-register to register it.
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How to get the plug-in depends on your distribution.
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<itemizedlist>
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<listitem><para>if you run GStreamer using packages for your distribution, you
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should check what packages are available for your distribution and see
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if any of the available packages contains the plug-in.
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</para></listitem>
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<listitem><para>if you run GStreamer from a source install, there's a good chance
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the plug-in didn't get built because you are missing an external library.
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When you ran configure, you should have gotten output of what plug-ins are
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going to be built. You can re-run configure to see if it's there.
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If it isn't, there is a good reason why it is not getting built.
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The most likely is that you're missing the library you need for it.
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Check the README file in gst-plugins to see what library you need.
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Make sure to remember to re-run configure after installing the supporting
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library !
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</para></listitem>
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<listitem><para>
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if you run GStreamer from CVS, the same logic applies as for a source install.
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Go over the reasons why the plug-in didn't get configured for build.
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Check output of config.log for a clue as to why it doesn't get built if
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you're sure you have the library needed installed in a sane place.
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</para></listitem>
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</itemizedlist>
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="troubleshooting-old-plug-ins">
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<para>
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I get an error that says something like
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(process:26626): GLib-GObject-WARNING **: specified instance size for type
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`DVDReadSrc' is smaller than the parent type's `GstElement' instance size
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What's wrong ?
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</para>
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</question>
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<answer>
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<para>
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If you run GStreamer CVS uninstalled, it means that something changed in
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the core that requires a recompilation in the plugins. Recompile the
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plugins by doing "make clean && make".
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</para>
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<para>
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If you run GStreamer installed, it probably means that you run the plugins
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against a different (incompatible) version than they were compiled against,
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which ususally means that you run multiple installations of GStreamer.
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Remove the old ones and - if needed - recompile again to ensure that it is
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using the right version.
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</para>
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<para>
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Note that we strongly recommend using Debian or RPM packages, since you will
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not get such issues if you use provided packages.
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="troubleshooting-segfault">
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<para>
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The GStreamer application I used stops with a segmentation fault. What can
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I do ?
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</para>
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</question>
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<answer>
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<para>
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There are two things you can do. If you compiled GStreamer with specific
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optimization compilation flags, you should try recompiling GStreamer,
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the application and the plug-ins without any optimization flags. This allows
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you to verify if the problem is due to optimization or due to bad code.
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Second, it will also allow you to provide a reasonable backtrace in case
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the segmentation fault still occurs.
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</para>
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<para>
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The second thing you can do is look at the backtrace to get an idea of where
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things are going wrong, or give us an idea of what is going wrong.
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To provide a backtrace, you should
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<orderedlist>
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<listitem><para>
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run the application in gdb by starting it with
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<programlisting>
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gdb (gst-application)
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</programlisting>
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(If the application is in a source tree instead of installed on the system,
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you might want to put "libtool" before "gdb")
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</para></listitem>
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<listitem><para>
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Pass on the command line arguments to the application by typing
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<programlisting>
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set args (the arguments to the application)
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</programlisting>
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at the (gdb) prompt
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</para></listitem>
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<listitem><para>
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Type "run" at the (gdb) prompt and wait for the application to
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segfault. The application will run a lot slower, however.
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</para></listitem>
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<listitem><para>
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After the segfault, type "bt" to get a backtrace. This is a stack of
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function calls detailing the path from main () to where the code is
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currently at.
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</para></listitem>
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<listitem><para>
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If the application you're trying to debug contains threads, it is also
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useful to do
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<programlisting>
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info threads
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</programlisting>
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and get backtraces of all of the threads involved, by switching to
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a different thread using "thread (number)" and then again requesting
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a backtrace using "bt".
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</para></listitem>
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<listitem><para>
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If you can't or don't want to work out the problem yourself, a copy and paste
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of all this information should be included in your
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<link linkend="using-bugs-where">bug report</link>.
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</para></listitem>
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</orderedlist>
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</para>
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</answer>
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</qandaentry>
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<qandaentry>
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<question id="troubleshooting-wiki">
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<para>
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I'm having problems building or installing GStreamer. What should I do ?
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</para>
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</question>
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<answer>
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<para>
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We've started a step-by-step
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<ulink url="http://gstreamer.net/wiki/?DichotomousKey">
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troubleshooting guide</ulink>.
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Look there before asking, your problem might already have been solved by
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someone else.
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</para>
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</answer>
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</qandaentry>
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</qandaset>
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</sect1>
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