2 Introduction
This tutorial is meant to be a quick way to get to know more about GStreamer but it'll take some time to
write it though because we don't know it ourselves . .. yet. We're usually using GNU/Linux and GTK in
the examples but we try to keep the GUI code to an absolute minimum so it should not get in the way.
Just remember that GStreamer depends heavily on Glib so you must make sure that the Glib Mainloop is
running if you want to catch events on the bus. We take for granted that you are at least a fairly descent
Python coder. For problems related to the Python language we redirect you over to Online Python docs.
There are also some example coding distributed with the PyGST source which you may browse at the
gst-python git repository. Reference documents for GStreamer and the rest of the ecosystem it relies on
are available at lazka's GitHub site. The main GStreamer site has Reference Manual, FAQ, Applications
Development Manual and Plugin Writer's Guide. This tutorial targets the GStreamer 1.0 API which all
v1.x releases should follow. The Novacut project has a guide to porting Python applications from the
prior 0.1 API to 1.0. Finally, GStreamer provides the GstSDK documentation which includes substantial
C programming tutorials.
As you may see this tutorial is far from done and we are always looking for new people to join this
project. If you want to write a chapter, x the examples, provide alternatives or otherwise improve this
document please do so. It is suggested to clone the repository on GitHub and issue a pull request. Note,
the original source of this document was here but is now dead.
2.1 Command Line
Before getting started with Python some of the command line interface (CLI) programs that come with
GStreamer are explored. Besides being generally useful they can help you nd and try out what you need
in a very fast and convenient way without writing a bit of code. With
gst-inspect
you can track highlevel
elements which are shipped with the various plugins packages.
man gst-inspect-1.0
If you are looking for an element but you don't know its name you can use it with grep. Getting the
elements that handles ie mp3 is done like this:
gst-inspect-1.0 | grep mp3 | sort | head -3
flump3dec: flump3dec: Fluendo MP3 Decoder (liboil build)
lame: lamemp3enc: L.A.M.E. mp3 encoder
libav: avdec_mp3adufloat: libav ADU (Application Data Unit) MP3 (MPEG audio layer 3) decoder
The
playbin
element is an autoplugger which usually plays anything you throw at it, if you have the
appropriate plugins installed.
gst-inspect-1.0 playbin > gst-inspect-playbin.txt
Browse example output here.
You can also run pipelines directly in a terminal with
gst-launch
:
man gst-launch-1.0
For playing a le with playbin:
gst-launch-1.0 playbin \
uri=http://docs.gstreamer.com/media/sintel_trailer-480p.webm
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