User Commands gst-launch(1)
NAME
gst-launch - build and run a GStreamer pipeline
SYNOPSIS
gst-launch [--exclude=type,type2,...] [--no-fault] [--
messages] [-output=file] [--tags] [--trace] [--verbose] [--
version] [gst-std-options] pipeline-description
DESCRIPTION
gst-launch builds and runs basic GStreamer pipelines.
In simple form, a pipeline-description is a list of elements
separated by exclamation marks (!). Properties can be
appended to elements, in the form property=value.
For a complete description of possible values for pipeline-
description, see the section Pipeline Description below or
consult the GStreamer documentation.
Please note that gst-launch is primarily a debugging tool
for developers and users. You should not build applications
on top of it. For applications, use the gstparselaunch()
function of the GStreamer API as an easy way to construct
pipelines from pipeline descriptions.
OPTIONS
The following options are supported by gst-launch:
-X, --exclude=type1,type2,... Do not output status infor-
mation of specified type.
-m, --messages Output messages posted on
the pipeline's bus.
-f, --no-fault Do not install a fault
handler.
-o, -output-=file Save XML representation of
pipeline to file, then exit.
-t, --tags Output tags, also known as
metadata.
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User Commands gst-launch(1)
-T, --trace Print memory allocation
trace, if enabled at compile
time.
-v, --verbose Output status information
and property notifications.
--version Print GStreamer version
number.
gst-std-options Standard options available
for use with most GStreamer
applications. See gst-std-
options(5) for more informa-
tion.
EXTENDED DESCRIPTION
Pipeline Description
A pipeline consists elements and links. elements can be put
into bins of different sorts. elements, links and bins can
be specified in a pipeline description in any order.
Elements
elementtype [property1 ...]
Creates an element of type elementtype and sets the proper-
ties.
Properties
property=value ...
Sets the property to the specified value. You can use gst-
inspect(1) to find out about properties and allowed values
of different elements.
Enumeration properties can be set by name, nick or value.
Bins
[bintype.] ( [property1 ...] pipeline-description )
Specifies that a bin of type bintype is created and the
given properties are set. Every element between the braces
is put into the bin. Please note the dot that has to be used
after the bintype. You will almost never need this
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User Commands gst-launch(1)
functionality, it is only really useful for applications
using the gstlaunchparse() API with 'bin' as bintype. That
way it is possible to build partial pipelines instead of a
full-fledged top-level pipeline.
Links
[srcelement].[pad1,...] ! [sinkelement].[pad1,...]
[srcelement].[pad1,...] ! caps !
[sinkelement].[pad1,...]
Links the element with name srcelement to the element with
name sinkelement, using the caps specified in caps as a
filter. Names can be set on elements with the name property.
If the name is omitted, the element that was specified
directly in front of or after the link is used. This works
across bins. If a padname is given, the link is done with
these pads. If no pad names are given all possibilities are
tried and a matching pad is used. If multiple padnames are
given, both sides must have the same number of pads speci-
fied and multiple links are done in the given order. So the
simplest link is a simple exclamation mark, that links the
element to the left of it to the element right of it.
Caps
mimetype [, property[, property ...] [; caps[; caps ...]
Creates a capability with the given mimetype and optionally
with given properties. The mimetype can be escaped using "
or '. If you want to chain caps, you can add more caps in
the same format afterwards.
Properties
name[:type]=value
in lists and ranges: [type=]value
Sets the requested property in capabilities. The name is an
alphanumeric value and the type can have the following
case-insensitive values:
]o i or int for integer values or ranges
]o f or float for float values or ranges
]o 4 or fourcc for FOURC values
]o b, bool, or boolean for boolean values
]o s, str, or string for strings
]o l or list for lists
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If no type was given, the following order is tried: integer,
float, boolean, string. Integer values must be parsable by
strtol(), floats by strtod(). FOURC values may either be
integers or strings. Boolean values are (case insensitive)
yes, no, true or false and may like strings be escaped with
" or '.
Ranges are in this format: [ property, property ]
Lists use this format: ( property [, property ...] )
Pipeline Control
A pipeline can be controlled by signals. SIGUSR2 will stop
the pipeline (GSTSTATENUL); SIGUSR1 will put it back to
play (GSTSTATEPLAYING). By default, the pipeline will
start in the playing state. There are currently no signals
defined to go into the ready or pause (GSTSTATEREADY and
GSTSTATEPAUSED) state explicitly.
EXAMPLES
The examples below assume that you have the correct plugins
available. In general, "sunaudiosink" can be substituted
with another audio output plugin such as "esdsink",
"alsasink", "osxaudiosink", or "artsdsink". Likewise, "xvi-
magesink" can be substituted with "ximagesink", "sdlvideo-
sink", "osxvideosink", or "aasink". Keep in mind though
that different sinks might accept different formats and even
the same sink might accept different formats on different
machines, so you might need to add converter elements like
audioconvert and audioresample (for audio) or
ffmpegcolorspace (for video) in front of the sink to make
things work.
Example 1: Audio Playback
Play the WAV music file "music.wav":
example% gst-launch filesrc location=music.wav ! wavparse ! sunaudiosink
Play the mp3 music file "music.mp3":
example% gst-launch filesrc location=music.mp3 ! flump3dec ! sunaudiosink
Play the Ogg Vorbis file "music.ogg":
example% gst-launch filesrc location=music.ogg ! oggdemux ! vorbisdec ! audioconvert ! sunaudiosink
Play an mp3 file or an http stream using GNOME-VFS:
example% gst-launch gnomevfssrc location=music.mp3 ! flump3dec ! sunaudiosink
example% gst-launch gnomevfssrc location=http:/domain.com/music.mp3 ! flump3dec ! sunaudiosink
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Use GNOME-VFS to play an mp3 file located on an SMB server:
example% gst-launch gnomevfssrc location=smb:/computer/music.mp3 ! flump3dec ! sunaudiosink
Example 2: Video Playback
Play an Ogg video file:
example% gst-launch filesrc location=video.ogg ! oggdemux ! theoradec ! ffmpegcolorspace ! xvimagesink
Example 3: Format Conversion
Convert an mp3 music file to the Ogg Vorbis format:
example% gst-launch filesrc location=music.mp3 ! flump3dec ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
Convert an mp3 music file to the FLAC format:
example% gst-launch filesrc location=music.mp3 ! flump3dec ! audioconvert ! flacenc ! filesink location=test.flac
Convert a .WAV file to the Ogg Vorbis format:
example% gst-launch filesrc location=music.wav ! wavparse ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
Example 4: Recording Audio
Record sound from your audio input and encode it into an Ogg
file:
example% gst-launch sunaudiosrc ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
Example 5: Compact Disk (CDA)
Play track number 3 from compact disc:
example% gst-launch cddasrc track=3 ! sunaudiosink
Play track number 5 from compact disc:
example% gst-launch cdda:/5 ! sunaudiosink
Example 6: Diagnostic
Generate a null stream and ignore it:
example% gst-launch fakesrc ! fakesink
Generate a pure tone to test the audio output:
example% gst-launch audiotestsrc ! sunaudiosink
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User Commands gst-launch(1)
Generate a familiar test pattern to test the video output:
example% gst-launch videotestsrc ! xvimagesink
Generate a familiar test pattern to test the video output:
example% gst-launch videotestsrc ! ximagesink
Example 7: Automatic Linking
You can use the decodebin element to automatically select
the right elements to get a working pipeline.
Play any supported audio format:
example% gst-launch filesrc location=musicfile ! decodebin ! sunaudiosink
Play any supported video format with video and audio output.
Threads are used automatically.
example% gst-launch filesrc location=videofile ! decodebin name=decoder decoder. ! queue ! audioconvert ! audioresample ! osssink decoder. ! ffmpegcolorspace ! xvimagesink
To make this even easier, you can use the playbin element:
example% gst-launch playbin uri=file:/home/joe/foo.avi
Example 8: Filtered Connections
These examples show how to use filtered capabilities.
Show a test image and use the YUY2 or YV12 video format for
this:
example% gst-launch videotestsrc ! video/x-raw-yuv,format=urcc)YUY2;video/x-raw-yuv,format=urcc)YV12 ! xvimagesink
Record audio and write it to a .wav file. Force usage of
signed 16 to 32 bit samples and a sample rate between 32kHz
and 64KHz:
example% gst-launch sunaudiosrc ! 'audio/x-raw-int,rate=[32000,64000],width=[16,32],depth={16,24,32},signed=(boolean)true' ! wavenc ! filesink location=recording.wav
FILES
The following files are used by this application:
/usr/bin/gst-launch Executable to build and run a
GStreamer pipeline
~/gstreamer-0.10/registrGS*treamer registry
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User Commands gst-launch(1)
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWgnome-media
Interface stability Volatile
SEE ALSO
gst-feedback(1), gst-inspect(1), gst-typefind(1), gst-
xmlinspect(1), gst-xmllaunch(1), gstreamer-properties(1),
libgstreamer-0.10(3), attributes(5), gst-std-options(5)
NOTES
Original man page written by the GStreamer team at
http:/www.gstreamer.net/.
Updated by Brian Cameron, Sun Microsystems Inc., 2004, 2006,
2007.
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