.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.

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

.

.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 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/