gstreamer/tools/gst-launch-1.0.1

.TH "GStreamer" "1" "May 2007"
.SH "NAME"
gst\-launch\-1.0 \- build and run a GStreamer pipeline
.SH "SYNOPSIS"
\fBgst\-launch\-1.0\fR \fI[OPTION...]\fR PIPELINE\-DESCRIPTION
.SH "DESCRIPTION"
.LP
\fIgst\-launch\-1.0\fP is a tool that builds and runs basic
\fIGStreamer\fP pipelines.

In simple form, a PIPELINE\-DESCRIPTION is a list of
elements separated by exclamation marks (!). Properties may be appended to
elements, in the form \fIproperty=value\fR. A "preset" can also be set using
the \fI@preset=<preset name>\fR syntax.

For a complete description of possible PIPELINE-DESCRIPTIONS see the section
\fIpipeline description\fR below or consult the GStreamer documentation.

Please note that \fIgst\-launch\-1.0\fP is primarily a debugging tool for
developers 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.
.
.SH "OPTIONS"
.l
\fIgst\-launch\-1.0\fP accepts the following options:
.TP 8
.B  \-\-help
Print help synopsis and available FLAGS
.TP 8
.B  \-v, \-\-verbose
Output status information and property notifications
.TP 8
.B  \-q, \-\-quiet
Do not print any progress information
.TP 8
.B  \-m, \-\-messages
Output messages posted on the pipeline's bus
.TP 8
.B  \-t, \-\-tags
Output tags (also known as metadata)
.TP 8
.B  \-e, \-\-eos\-on\-shutdown
Force an EOS event on sources before shutting the pipeline down. This is
useful to make sure muxers create readable files when a muxing pipeline is
shut down forcefully via Control-C.
.TP 8
.B  \-i, \-\-index
Gather and print index statistics. This is mostly useful for playback or
recording pipelines.
.TP 8
.B  \-f, \-\-no\-fault
Do not install a fault handler
.TP 8
.B  \-T, \-\-trace
Print memory allocation traces. The feature must be enabled at compile time to
work.
.TP 8
.B  \-\-no\-position
Do not print current position of pipeline.
If this option is unspecified, the position will be printed when stdout is a TTY.
To enable printing position when stdout is not a TTY,
use "force-position" option.
.TP 8
.B  \-\-force\-position
Allow printing current position of pipeline even if stdout is not a TTY.
This option has no effect if the "no-position" option is specified.
.TP 8

.
.SH "GSTREAMER OPTIONS"
.l
\fIgst\-launch\-1.0\fP also accepts the following options that are common
to all GStreamer applications:
.TP 8
.B  \-\-gst\-version
Prints the version string of the \fIGStreamer\fP core library.
.TP 8
.B  \-\-gst\-fatal\-warnings
Causes \fIGStreamer\fP to abort if a warning message occurs. This is equivalent
to setting the environment variable G_DEBUG to 'fatal_warnings' (see the
section \fIenvironment variables\fR below for further information).
.TP 8
.B  \-\-gst\-debug=STRING
A comma separated list of category_name:level pairs to specify debugging levels
for each category. Level is in the range 0-9 where 0 will show no messages, and
9 will show all messages. The wildcard * can be used to match category names.
Note that the order of categories and levels is important, wildcards at the
end may override levels set earlier. The log levels are: 1=ERROR, 2=WARNING,
3=FIXME, 4=INFO, 5=DEBUG, 6=LOG, 7=TRACE, 9=MEMDUMP. Since GStreamer 1.2 one
can also use the debug level names, e.g. \-\-gst\-debug=*sink:LOG. A full
description of the various debug levels can be found in the GStreamer core
library API documentation, in the "Running GStreamer Applications" section.

Use \-\-gst\-debug\-help to show category names

Example:
GST_CAT:5,GST_ELEMENT_*:3,oggdemux:5

.TP 8
.B  \-\-gst\-debug\-level=LEVEL
Sets the threshold for printing debugging messages.  A higher level
will print more messages.  The useful range is 0-9, with the default
being 0. Level 6 (LOG level) will show all information that is usually
required for debugging purposes. Higher levels are only useful in very
specific cases. See above for the full list of levels.
.TP 8
.B  \-\-gst\-debug\-no\-color
\fIGStreamer\fP normally prints debugging messages so that the
messages are color-coded when printed to a terminal that handles
ANSI escape sequences.  Using this option causes \fIGStreamer\fP
to print messages without color. Setting the \fBGST_DEBUG_NO_COLOR\fR
environment variable will achieve the same thing.
.TP 8
.B  \-\-gst\-debug\-color\-mode
\fIGStreamer\fP normally prints debugging messages so that the
messages are color-coded when printed to a terminal that handles
ANSI escape sequences (on *nix), or uses W32 console API to color the
messages printed into a console (on W32). Using this option causes
\fIGStreamer\fP to print messages without color ('off' or 'disable'),
print messages with default colors ('on' or 'auto'), or print messages
using ANSI escape sequences for coloring ('unix'). Setting the
\fBGST_DEBUG_COLOR_MODE\fR environment variable will achieve the same thing.
.TP 8
.B  \-\-gst\-debug\-disable
Disables debugging.
.TP 8
.B  \-\-gst\-debug\-help
Prints a list of available debug categories and their default debugging level.
.TP 8
.B  \-\-gst\-plugin\-spew
\fIGStreamer\fP info flags to set
Enable printout of errors while loading \fIGStreamer\fP plugins
.TP 8
.B  \-\-gst\-plugin\-path=PATH
Add directories separated with ':' to the plugin search path
.TP 8
.B  \-\-gst\-plugin\-load=PLUGINS
Preload plugins specified in a comma-separated list. Another way to specify
plugins to preload is to use the environment variable GST_PLUGIN_PATH

.SH "PIPELINE DESCRIPTION"

A pipeline consists \fIelements\fR and \fIlinks\fR. \fIElements\fR can be put
into \fIbins\fR of different sorts. \fIElements\fR, \fIlinks\fR and \fIbins\fR
can be specified in a pipeline description in any order.

.B Elements

ELEMENTTYPE \fI[PROPERTY1 ...]\fR

Creates an element of type ELEMENTTYPE and sets the PROPERTIES.

.B Properties

PROPERTY=VALUE ...

Sets the property to the specified value. You can use \fBgst\-inspect\-1.0\fR(1) to
find out about properties and allowed values of different elements.
.br
Enumeration properties can be set by name, nick or value.

.B Presets

@preset=<preset name> ...

Sets the preset on the element. you can use \fbgst\-inspect\-1.0\fr(1) to
find out what presets are available for a specific element.

.B Bins

\fI[BINTYPE.]\fR ( \fI[PROPERTY1 ...]\fR PIPELINE-DESCRIPTION )
.br

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
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.

.B Links

\fI[[SRCELEMENT].[PAD1,...]]\fR ! \fI[[SINKELEMENT].[PAD1,...]]\fR
\fI[[SRCELEMENT].[PAD1,...]]\fR ! CAPS ! \fI[[SINKELEMENT].[PAD1,...]]\fR
\fI[[SRCELEMENT].[PAD1,...]]\fR : \fI[[SINKELEMENT].[PAD1,...]]\fR
\fI[[SRCELEMENT].[PAD1,...]]\fR : CAPS : \fI[[SINKELEMENT].[PAD1,...]]\fR

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.
.br
So the simplest link is a simple exclamation mark, that links the element to
the left of it to the element right of it.
.br
Linking using the : operator attempts to link all possible pads between
the elements
.br

.B Caps

MEDIATYPE \fI[, PROPERTY[, PROPERTY ...]]]\fR \fI[; CAPS[; CAPS ...]]\fR

Creates a capability with the given media type and optionally with given
properties. The media type can be escaped using " or '.
If you want to chain caps, you can add more caps in the same format afterwards.

.B Properties

NAME=\fI[(TYPE)]\fRVALUE
.br
in lists and ranges: \fI[(TYPE)]\fRVALUE

Sets the requested property in capabilities. The name is an alphanumeric value
and the type can have the following case-insensitive values:
.br
- \fBi\fR or \fBint\fR for integer values or ranges
.br
- \fBf\fR or \fBfloat\fR for float values or ranges
.br
- \fBb\fR, \fBbool\fR or \fBboolean\fR for boolean values
.br
- \fBs\fR, \fBstr\fR or \fBstring\fR for strings
.br
- \fBfraction\fR for fractions (framerate, pixel\-aspect\-ratio)
.br
- \fBl\fR or \fBlist\fR for lists
.br
If no type was given, the following order is tried: integer, float, boolean,
string.
.br
Integer values must be parsable by \fBstrtol()\fP, floats by \fBstrtod()\fP. FOURCC values may
either be integers or strings. Boolean values are (case insensitive) \fIyes\fR,
\fIno\fR, \fItrue\fR or \fIfalse\fR and may like strings be escaped with " or '.
.br
Ranges are in this format:  [ VALUE, VALUE ]
.br
Lists use this format:      { VALUE \fI[, VALUE ...]\fR }

.SH "PIPELINE EXAMPLES"

The examples below assume that you have the correct plug-ins available.
In general, "pulsesink" can be substituted with another audio output
plug-in such as "alsasink" or "osxaudiosink"
Likewise, "xvimagesink" can be substituted with "ximagesink", "glimagesink",
or "osxvideosink". 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 videoconvert (for video)
in front of the sink to make things work.

.B Audio playback

Play the mp3 music file "music.mp3" using a libmpg123-based plug-in and
output to an Pulseaudio device
.br
.B
        gst\-launch\-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink

Play an Ogg Vorbis format file
.br
.B
        gst\-launch\-1.0 filesrc location=music.ogg ! oggdemux ! vorbisdec ! audioconvert ! audioresample ! pulsesink

Play an mp3 file or an http stream using GIO
.br
.B
        gst\-launch\-1.0 giosrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! pulsesink
.br
.B
        gst\-launch\-1.0 giosrc location=http://domain.com/music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink

Use GIO to play an mp3 file located on an SMB server
.br
.B
        gst\-launch\-1.0 giosrc location=smb://computer/music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink

.B Format conversion

Convert an mp3 music file to an Ogg Vorbis file
.br
.B
        gst\-launch\-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg

Convert to the FLAC format
.br
.B
        gst\-launch\-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! flacenc ! filesink location=test.flac

.B Other

Plays a .WAV file that contains raw audio data (PCM).
.br
.B
        gst\-launch\-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! audioresample ! pulsesink

Convert a .WAV file containing raw audio data into an Ogg Vorbis or mp3 file
.br
.B
        gst\-launch\-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
.br
.B
        gst\-launch\-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! lamemp3enc ! filesink location=music.mp3

Rips all tracks from compact disc and convert them into a single mp3 file
.br
.B
        gst\-launch\-1.0 cdparanoiasrc mode=continuous ! audioconvert ! lamemp3enc ! mpegaudioparse ! id3v2mux ! filesink location=cd.mp3

Rips track 5 from the CD and converts it into a single mp3 file
.br
.B
        gst\-launch\-1.0 cdparanoiasrc track=5 ! audioconvert ! lamemp3enc ! mpegaudioparse ! id3v2mux ! filesink location=track5.mp3

Using \fBgst\-inspect\-1.0\fR(1), it is possible to discover settings like the above
for cdparanoiasrc that will tell it to rip the entire cd or only tracks of it.
Alternatively, you can use an URI and gst\-launch\-1.0 will find an element (such as
cdparanoia) that supports that protocol for you, e.g.:
.B
       gst\-launch\-1.0 cdda://5 ! lamemp3enc vbr=new vbr\-quality=6 ! filesink location=track5.mp3

Records sound from your audio input and encodes it into an ogg file
.br
.B
        gst\-launch\-1.0 pulsesrc ! audioconvert ! vorbisenc ! oggmux ! filesink location=input.ogg

.B Video

Display only the video portion of an MPEG-1 video file, outputting to
an X display window
.br
.B
        gst\-launch\-1.0 filesrc location=JB_FF9_TheGravityOfLove.mpg ! dvddemux ! mpegvideoparse ! mpeg2dec ! xvimagesink

Display the video portion of a .vob file (used on DVDs), outputting to
an SDL window
.br
.B
        gst\-launch\-1.0 filesrc location=/flflfj.vob ! dvddemux ! mpegvideoparse ! mpeg2dec ! sdlvideosink

Play both video and audio portions of an MPEG movie
.br
.B
        gst\-launch\-1.0 filesrc location=movie.mpg ! dvddemux name=demuxer  demuxer. ! queue ! mpegvideoparse ! mpeg2dec ! sdlvideosink  demuxer. ! queue ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink

Play an AVI movie with an external text subtitle stream
.br
.B
        gst\-launch\-1.0 filesrc location=movie.mpg ! mpegdemux name=demuxer demuxer. ! queue ! mpegvideoparse ! mpeg2dec ! videoconvert ! sdlvideosink   demuxer. ! queue ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink

This example also shows how to refer to specific pads by name if an element
(here: textoverlay) has multiple sink or source pads.
.br
.B
        gst\-launch\-1.0 textoverlay name=overlay ! videoconvert ! videoscale !  autovideosink   filesrc location=movie.avi ! decodebin ! videoconvert ! overlay.video_sink   filesrc location=movie.srt ! subparse ! overlay.text_sink

Play an AVI movie with an external text subtitle stream using playbin
.br
.B
        gst\-launch\-1.0 playbin uri=file:///path/to/movie.avi suburi=file:///path/to/movie.srt

.B Network streaming

Stream video using RTP and network elements.

This command would be run on the transmitter
.br
.B
        gst\-launch\-1.0 v4l2src ! video/x\-raw,width=128,height=96,format=UYVY ! videoconvert ! ffenc_h263 ! video/x\-h263 ! rtph263ppay pt=96 ! udpsink host=192.168.1.1 port=5000

Use this command on the receiver
.br
.B
        gst\-launch\-1.0 udpsrc port=5000 ! application/x\-rtp, clock\-rate=90000,payload=96 ! rtph263pdepay queue\-delay=0 ! ffdec_h263 ! xvimagesink

.B Diagnostic

Generate a null stream and ignore it (and print out details).
.br
.B
        gst\-launch\-1.0 \-v fakesrc num\-buffers=16 ! fakesink

Generate a pure sine tone to test the audio output
.br
.B
        gst\-launch\-1.0 audiotestsrc ! audioconvert ! audioresample ! pulsesink

Generate a familiar test pattern to test the video output
.br
.B
        gst\-launch\-1.0 videotestsrc ! xvimagesink
.br
.B
        gst\-launch\-1.0 videotestsrc ! ximagesink

.B Automatic linking

You can use the decodebin element to automatically select the right elements
to get a working pipeline.

Play any supported audio format
.br
.B
        gst\-launch\-1.0 filesrc location=musicfile ! decodebin ! audioconvert ! audioresample ! pulsesink

Play any supported video format with video and audio output. Threads are used
automatically. To make this even easier, you can use the playbin element:
.br
.B
        gst\-launch\-1.0 filesrc location=videofile ! decodebin name=decoder decoder. ! queue ! audioconvert ! audioresample ! pulsesink   decoder. !  videoconvert ! xvimagesink
.br
.B
        gst\-launch\-1.0 playbin uri=file:///home/joe/foo.avi


.B Filtered connections

These examples show you how to use filtered caps.

Show a test image and use the YUY2 or YV12 video format for this.
.br
.B
        gst\-launch\-1.0 videotestsrc ! 'video/x\-raw,format=YUY2;video/x\-raw,format=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.
.br
.B
        gst\-launch\-1.0 pulsesrc !  'audio/x\-raw,rate=[32000,64000],format={S16LE,S24LE,S32LE}' ! wavenc ! filesink location=recording.wav


.SH "ENVIRONMENT VARIABLES"
.TP
\fBGST_DEBUG\fR
Comma-separated list of debug categories and levels (e.g.
GST_DEBUG=totem:4,typefind:5). '*' is allowed as a wildcard as part of
debug category names (e.g. GST_DEBUG=*sink:6,*audio*:6). Since 1.2.0 it is
also possible to specify the log level by name (1=ERROR, 2=WARN, 3=FIXME,
4=INFO, 5=DEBUG, 6=LOG, 7=TRACE, 9=MEMDUMP) (e.g. GST_DEBUG=*audio*:LOG)
.TP
\fBGST_DEBUG_NO_COLOR\fR
When this environment variable is set, coloured debug output is disabled.
.TP
\fBGST_DEBUG_DUMP_DOT_DIR\fR
When set to a filesystem path, store 'dot' files of pipeline graphs there.
These can then later be converted into an image using the 'dot' utility from
the graphviz set of tools, like this: dot foo.dot \-Tsvg \-o foo.svg (png or jpg
are also possible as output format). There is also a utility called 'xdot'
which allows you to view the .dot file directly without converting it first.
.br
When the pipeline changes state through NULL to PLAYING and back to NULL, a
dot file is generated on each state change. To write a snapshot of the
pipeline state, send a SIGHUP to the process.
.TP
\fBGST_REGISTRY\fR
Path of the plugin registry file. Default is
~/.cache/gstreamer\-1.0/registry\-CPU.bin where CPU is the
machine/cpu type GStreamer was compiled for, e.g. 'i486', 'i686', 'x86\-64', 'ppc',
etc. (check the output of "uname \-i" and "uname \-m" for details).
.TP
\fBGST_REGISTRY_UPDATE\fR
Set to "no" to force GStreamer to assume that no plugins have changed,
been added or been removed. This will make GStreamer skip the initial check
whether a rebuild of the registry cache is required or not. This may be useful
in embedded environments where the installed plugins never change. Do not
use this option in any other setup.
.TP
\fBGST_PLUGIN_PATH\fR
Specifies a list of directories to scan for additional plugins.
These take precedence over the system plugins.
.TP
\fBGST_PLUGIN_SYSTEM_PATH\fR
Specifies a list of plugins that are always loaded by default.  If not set,
this defaults to the system-installed path, and the plugins installed in the
user's home directory
.TP
\fBGST_DEBUG_FILE\fR
Set this variable to a file path to redirect all GStreamer debug
messages to this file. If left unset, debug messages with be output
unto the standard error.
.TP
\fBORC_CODE\fR
Useful Orc environment variable. Set ORC_CODE=debug to enable debuggers
such as gdb to create useful backtraces from Orc-generated code.  Set
ORC_CODE=backup or ORC_CODE=emulate if you suspect Orc's SIMD code
generator is producing incorrect code.  (Quite a few important
GStreamer plugins like videotestsrc, audioconvert or audioresample use Orc).
.TP
\fBG_DEBUG\fR
Useful GLib environment variable. Set G_DEBUG=fatal_warnings to make
GStreamer programs abort when a critical warning such as an assertion failure
occurs. This is useful if you want to find out which part of the code caused
that warning to be triggered and under what circumstances. Simply set G_DEBUG
as mentioned above and run the program in gdb (or let it core dump). Then get
a stack trace in the usual way.
.
.SH FILES
.TP 8
~/.cache/gstreamer\-1.0/registry\-*.bin
The plugin cache; can be deleted at any time, will be re-created
automatically when it does not exist yet or plugins change. Based on
XDG_CACHE_DIR, so may be in a different location than the one suggested.
.
.SH "SEE ALSO"
.BR gst\-inspect\-1.0 (1),
.BR gst\-launch\-1.0 (1),
.SH "AUTHOR"
The GStreamer team at http://gstreamer.freedesktop.org/