mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-04 23:46:43 +00:00
92b1df0186
Fix link to gst-uninstalled now that it's been moved, and fix a typo while we're at it. Also add a new section to 'Building GStreamer from git' that points to the 'How do I develop against an uninstalled copy of GStreamer' section.
221 lines
8.8 KiB
XML
221 lines
8.8 KiB
XML
<sect1 id="chapter-developing">
|
|
<title id="title-developing">Developing applications with GStreamer</title>
|
|
<qandaset defaultlabel="qanda">
|
|
|
|
<qandaentry>
|
|
<question id="developing-compile-programs">
|
|
<para>How do I compile programs that use GStreamer ?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
GStreamer uses pkg-config to assist applications with compilation and
|
|
linking flags.
|
|
pkg-config is already used by GTK+, GNOME, SDL, and others; so if you are
|
|
familiar with using it for any of those, you're set.
|
|
</para>
|
|
<para>
|
|
If you're not familiar with pkg-config to compile and link a small
|
|
one-file program, pass the --cflags and --libs arguments to pkg-config.
|
|
For example:
|
|
<programlisting>
|
|
$ libtool --mode=link gcc `pkg-config --cflags --libs gstreamer-&GST_MAJORMINOR;` -o myprog myprog.c
|
|
</programlisting>
|
|
would be sufficient for a gstreamer-only program.
|
|
If (for example) your app also used GTK+ 2.0, you could use
|
|
<programlisting>
|
|
$ libtool --mode=link gcc `pkg-config --cflags --libs gstreamer-&GST_MAJORMINOR; gtk+-2.0` -o myprog myprog.c
|
|
</programlisting>
|
|
Those are back-ticks (on the same key with the tilde on US keyboards),
|
|
not single quotes.
|
|
</para>
|
|
<para>
|
|
For bigger projects, you should integrate pkg-config use in your Makefile,
|
|
or integrate with autoconf using the pkg.m4 macro (providing PKG_CONFIG_CHECK).
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-uninstalled-gstreamer">
|
|
<para>How do I develop against an uninstalled GStreamer copy ?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
It is possible to develop and compile against an uninstalled copy of
|
|
gstreamer and gst-plugins-* (for example, against gits checkouts).
|
|
The easiest way to do this is to use a bash script like this:
|
|
<ulink url="http://cgit.freedesktop.org/gstreamer/gstreamer/tree/scripts/gst-uninstalled">latest version of gst-uninstalled</ulink>.
|
|
|
|
If you put this script in your path, and symlink it to gst-git (if you want
|
|
to develop against git master) or to gst-released (if you want to develop
|
|
against the lastest release of each module), it will automatically use the
|
|
uninstalled version from that directory (ie. gst-git will look for a directory
|
|
called 'git', and gst-released will expect the uninstalled modules to be in
|
|
the 'released' directory; you are free to use any name or identifier you like
|
|
here).
|
|
</para>
|
|
<para>
|
|
This requires you to have put your checkouts of gstreamer and gst-plugins
|
|
under ~/gst/git (for the master version). The program is easily modifiable
|
|
if this isn't the case.
|
|
</para>
|
|
<para>
|
|
After running this script, you'll be in an environment where the uninstalled
|
|
tools and plugins will be used by default. Also, pkg-config will detect the
|
|
uninstalled copies before (and prefer them to) any installed copies.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-gconf">
|
|
<para>How can I use GConf to get the system-wide defaults ?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
For GNOME applications it's a good idea to use GConf to find the default ways
|
|
of outputting audio and video. You can do this by using the 'gconfaudiosink'
|
|
and 'gconfvideosink' elements for audio and video output. They will take
|
|
care of everything GConf-related for you and automatically use the outputs
|
|
that the user configured. If you are using gconfaudiosink, your application
|
|
should set the 'profile' property.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-libtool-scripts">
|
|
<para>
|
|
How do I debug these funny shell scripts that libtool makes ?
|
|
</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
When you link a program against uninstalled GStreamer using libtool,
|
|
funny shell scripts are made to modify your shared object search path
|
|
and then run your program. For instance, to debug gst-launch, try
|
|
<programlisting>
|
|
libtool --mode=execute gdb /path/to/gst-launch
|
|
</programlisting>.
|
|
If this does not work, you're probably using a broken version of libtool.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-mail-gstreamer-devel">
|
|
<para>Why is mail traffic so low on gstreamer-devel ?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
Our main arena for coordination and discussion is IRC, not email.
|
|
Join us in <ulink url="irc://irc.freenode.net/#gstreamer">#gstreamer on irc.freenode.net</ulink>
|
|
For larger picture questions or getting more input from more persons,
|
|
a mail to gstreamer-devel is never a bad idea.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-versioning">
|
|
<para>What kind of versioning scheme does GStreamer use ?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
For public releases, GStreamer uses a standard MAJOR.MINOR.MICRO version
|
|
scheme. If the release consists of mostly bug fixes or incremental changes,
|
|
the MICRO version is incremented.
|
|
If the release contains big changes, the MINOR version is incremented.
|
|
If we're particularly giddy, we might even increase the MAJOR number.
|
|
Don't hold your breath for that though.
|
|
</para>
|
|
<para>
|
|
During the development cycle, GStreamer also uses a fourth or NANO number.
|
|
If this number is 1, then it's a git development version.
|
|
Any tarball or package that has a nano number of 1 is made from git and thus
|
|
not supported. Additionally, if you didn't get this package or tarball from
|
|
the GStreamer team, don't have high hopes on it doing whatever you want it
|
|
to do.
|
|
</para>
|
|
<para>
|
|
If the number is 2 or higher, it's an official pre-release in preparation
|
|
of an actual complete release. Your help in testing these tarballs and
|
|
packages is very much appreciated.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
|
|
<qandaentry>
|
|
<question id="developing-coding-style">
|
|
<para>What is the coding style for GStreamer code?</para>
|
|
</question>
|
|
|
|
<answer>
|
|
<para>
|
|
The core and almost all plugin modules are basically coded in K&R with
|
|
2-space indenting. Just follow what's already there and you'll be fine.
|
|
</para>
|
|
<para>
|
|
Individual plugins in gst-plugins-* or plugins that you want considered for
|
|
addition to one of the gst-plugins-* modules should be coded in the same style.
|
|
It's easier if everything is consistent. Consistency is, of course, the goal.
|
|
</para>
|
|
<para>
|
|
Simply run your code (only the *.c files, not the header files) through
|
|
<programlisting>
|
|
indent \
|
|
--braces-on-if-line \
|
|
--case-brace-indentation0 \
|
|
--case-indentation2 \
|
|
--braces-after-struct-decl-line \
|
|
--line-length80 \
|
|
--no-tabs \
|
|
--cuddle-else \
|
|
--dont-line-up-parentheses \
|
|
--continuation-indentation4 \
|
|
--honour-newlines \
|
|
--tab-size8 \
|
|
--indent-level2
|
|
</programlisting>
|
|
before submitting a patch. (This is using GNU indent.) There is also a
|
|
gst-indent script in the GStreamer core source tree in the tools directory
|
|
which wraps this and contains the latest option. The easiest way to get the
|
|
indenting right is probably to develop against a git checkout. The local
|
|
git commit hook will ensure correct indentation. We only require code files to
|
|
be indented, header files may be indented manually for better readability
|
|
(however, please use spaces for indenting, not tabs, even in header files).
|
|
</para>
|
|
<para>
|
|
As for the code itself, the
|
|
<ulink url="http://developer.gnome.org/doc/guides/programming-guidelines/book1.html">GNOME coding guidelines</ulink> is a good read.
|
|
Where possible, we try to adhere to the spirit of GObject and use similar
|
|
coding idioms.
|
|
</para>
|
|
<para>
|
|
Patches should be made against git master or the latest release and should be
|
|
in 'unified context' format (use diff -u -p). They should be attached to
|
|
a bug report (or feature request) in
|
|
<ulink url="http://bugzilla.gnome.org">bugzilla</ulink> rather than
|
|
sent to the mailing list. Also see
|
|
<ulink url="http://gstreamer.freedesktop.org/wiki/SubmittingPatches">SubmittingPatches</ulink>
|
|
in the GStreamer wiki.
|
|
</para>
|
|
</answer>
|
|
</qandaentry>
|
|
<qandaentry>
|
|
<question id="developing-translations">
|
|
<para>I have translated one of the module .po files into a new language. How do I get it included?</para>
|
|
</question>
|
|
<answer>
|
|
<para>GStreamer translations are uniformly managed through the Translation Project (http://translationproject.org). There are some instructions on how to join the Translation Project team and submit new translations at http://translationproject.org/html/translators.html.</para>
|
|
<para>New translations submitted via the Translation Project are merged periodically into git by the maintainers by running 'make download-po' in the various modules.</para>
|
|
</answer>
|
|
</qandaentry>
|
|
</qandaset>
|
|
</sect1>
|