Ubuntu Manpage: gst-launch-1.0 - build and run a GStreamer pipeline

Provided by: gstreamer1.0-tools_1.14.5-0ubuntu1~18.04.2_amd64

NAME

       gst-launch-1.0 - build and run a GStreamer pipeline

SYNOPSIS

       gst-launch-1.0 [OPTION...] PIPELINE-DESCRIPTION

DESCRIPTION

       gst-launch-1.0 is a tool that builds and runs basic GStreamer 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 property=value.

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

       Please  note  that  gst-launch-1.0 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.

OPTIONS

gst-launch-1.0 accepts the following options:

--help Print help synopsis and available FLAGS

-v, --verbose
Output status information and property notifications

-q, --quiet
Do not print any progress information

-m, --messages
Output messages posted on the pipeline's bus

-t, --tags
Output tags (also known as metadata)

-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.

-i, --index
Gather and print index statistics. This is mostly useful for playback or recording pipelines.

-f, --no-fault
Do not install a fault handler

-T, --trace
Print memory allocation traces. The feature must be enabled at compile time to work.

GSTREAMER OPTIONS
gst-launch-1.0 also accepts the following options that are common to all GStreamer applications:

--gst-version
Prints the version string of the GStreamer core library.

--gst-fatal-warnings
Causes GStreamer to abort if a warning message occurs. This is equivalent to setting the
environment variable G_DEBUG to 'fatal_warnings' (see the section environment variables below for
further information).

--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

--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.

--gst-debug-no-color
GStreamer 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 GStreamer to print
messages without color. Setting the GST_DEBUG_NO_COLOR environment variable will achieve the same
thing.

--gst-debug-color-mode
GStreamer 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 GStreamer 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 GST_DEBUG_COLOR_MODE
environment variable will achieve the same thing.

--gst-debug-disable
Disables debugging.

--gst-debug-help
Prints a list of available debug categories and their default debugging level.

--gst-plugin-spew
GStreamer info flags to set Enable printout of errors while loading GStreamer plugins

--gst-plugin-path=PATH
Add directories separated with ':' to the plugin search path

--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

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-1.0(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  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,...]]          [[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.
       Linking using the : operator attempts to link all possible pads between the elements

       Caps

       MEDIATYPE [, PROPERTY[, PROPERTY ...]]] [; CAPS[; CAPS ...]]

       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.

       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:
       - i or int for integer values or ranges
       - f or float for float values or ranges
       - b, bool or boolean for boolean values
       - s, str or string for strings
       - fraction for fractions (framerate, pixel-aspect-ratio)
       - 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:  [ VALUE, VALUE ]
       Lists use this format:      { VALUE [, VALUE ...] }

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.

Audio playback

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

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

Play an mp3 file or an http stream using GIO
gst-launch-1.0 giosrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert !
pulsesink
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
gst-launch-1.0 giosrc location=smb://computer/music.mp3 ! mpegaudioparse ! mpg123audiodec !
audioconvert ! audioresample ! pulsesink

Format conversion

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

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

Other

Plays a .WAV file that contains raw audio data (PCM).
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
gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! vorbisenc ! oggmux !
filesink location=music.ogg
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
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
gst-launch-1.0 cdparanoiasrc track=5 ! audioconvert ! lamemp3enc ! mpegaudioparse ! id3v2mux !
filesink location=track5.mp3

Using gst-inspect-1.0(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.:
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
gst-launch-1.0 pulsesrc ! audioconvert ! vorbisenc ! oggmux ! filesink location=input.ogg

Video

Display only the video portion of an MPEG-1 video file, outputting to an X display window
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
gst-launch-1.0 filesrc location=/flflfj.vob ! dvddemux ! mpegvideoparse ! mpeg2dec ! sdlvideosink

Play both video and audio portions of an MPEG movie
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
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.
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
gst-launch-1.0 playbin uri=file:///path/to/movie.avi suburi=file:///path/to/movie.srt

Network streaming

Stream video using RTP and network elements.

This command would be run on the transmitter
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
gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, clock-rate=90000,payload=96 ! rtph263pdepay
queue-delay=0 ! ffdec_h263 ! xvimagesink

Diagnostic

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

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

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

Automatic linking

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

Play any supported audio format
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:
gst-launch-1.0 filesrc location=videofile ! decodebin name=decoder decoder. ! queue !
audioconvert ! audioresample ! pulsesink decoder. ! videoconvert ! xvimagesink
gst-launch-1.0 playbin uri=file:///home/joe/foo.avi

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.
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.
gst-launch-1.0 pulsesrc ! 'audio/x-raw,rate=[32000,64000],format={S16LE,S24LE,S32LE}' ! wavenc !
filesink location=recording.wav

ENVIRONMENT VARIABLES

GST_DEBUG
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)

GST_DEBUG_NO_COLOR
When this environment variable is set, coloured debug output is disabled.

GST_DEBUG_DUMP_DOT_DIR
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.
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.

GST_REGISTRY
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).

GST_REGISTRY_UPDATE
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.

GST_PLUGIN_PATH
Specifies a list of directories to scan for additional plugins. These take precedence over the
system plugins.

GST_PLUGIN_SYSTEM_PATH
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

GST_DEBUG_FILE
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.

ORC_CODE
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).

G_DEBUG
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.

FILES

       ~/.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.

AUTHOR

       The GStreamer team at http://gstreamer.freedesktop.org/

                                                    May 2007                                        GStreamer(1)