gst-launch(1) User Commands gst-launch(1)NAMEgst-launch - build and run a GStreamer pipeline
SYNOPSISgst-launch [--exclude=type,type2,...] [--no-fault] [--messages] [-out‐
put=file] [--tags] [--trace] [--verbose] [--version] [gst-std-options]
pipeline-description
DESCRIPTIONgst-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 develop‐
ers and users. You should not build applications on top of it. For
applications, use the gst_parse_launch() 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 information of
specified type.
-m, --messages Output messages posted on the pipe‐
line'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.
-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 information.
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 properties.
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 proper‐
ties 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 functionality, it is only really useful for
applications using the gst_launch_parse() 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 specified 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 alphanu‐
meric value and the type can have the following case-insensitive val‐
ues:
· i or int for integer values or ranges
· f or float for float values or ranges
· 4 or fourcc for FOURCC values
· b, bool, or boolean for boolean values
· s, str, or string for strings
· l or list for lists
If no type was given, the following order is tried: integer, float,
boolean, string. Integer values must be parsable by strtol(), floats
by strtod(). FOURCC 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
(GST_STATE_NULL); SIGUSR1 will put it back to play (GST_STATE_PLAYING).
By default, the pipeline will start in the playing state. There are
currently no signals defined to go into the ready or pause
(GST_STATE_READY and GST_STATE_PAUSED) 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, "xvimagesink" can be substituted with "ximagesink",
"sdlvideosink", "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
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 (CDDA)
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
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.
/usr/lib/gstreamer-0.10/
GStreamer system plugin directory.
~/gstreamer-0.10/plugins
GStreamer user-specific plugin directory.
~/gstreamer-0.10/registry-*.xml
GStreamer plugin registry for user.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │library/audio/gstreamer │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOgst-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.
SunOS 5.11 12 Nov 2007 gst-launch(1)
