SYNOPSIS

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

DESCRIPTION

gst-launch 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 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 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.

-o FILE, --output=FILE

Save XML representation of pipeline to FILE and exit (DEPRECATED, DO NOT USE)

-f, --no-fault

Do not install a fault handler

--no-sigusr-handler

Do not install signal handlers for SIGUSR1 (play) and SIGUSR2 (stop)

-T, --trace

Print memory allocation traces. The feature must be enabled at compile time to work.

GSTREAMER OPTIONS

gst-launch 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 0-5 where 0 will show no messages, and 5 will show all messages. The wildcard * can be used to match category names.

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 0-5, with the default being 0.

--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-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) 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,...]]

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 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
- 4 or fourcc for FOURCC values
- 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 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.

PIPELINE EXAMPLES

The examples below assume that you have the correct plug-ins available. In general, "osssink" can be substituted with another audio output plug-in 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.

Audio playback

        gst-launch filesrc location=music.mp3 ! mad ! audioconvert ! audioresample ! osssink
Play the mp3 music file "music.mp3" using a libmad-based plug-in and output to an OSS device

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

        gst-launch gnomevfssrc location=music.mp3 ! mad ! osssink

        gst-launch gnomevfssrc location=http://domain.com/music.mp3 ! mad ! audioconvert ! audioresample ! osssink
Play an mp3 file or an http stream using GNOME-VFS

        gst-launch gnomevfssrc location=smb://computer/music.mp3 ! mad ! audioconvert ! audioresample ! osssink
Use GNOME-VFS to play an mp3 file located on an SMB server

Format conversion

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

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

Other

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

        gst-launch filesrc location=music.wav ! wavparse ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg

        gst-launch filesrc location=music.wav ! wavparse ! audioconvert ! lame ! filesink location=music.mp3
Convert a .WAV file containing raw audio data into an Ogg Vorbis or mp3 file

        gst-launch cdparanoiasrc mode=continuous ! audioconvert ! lame ! id3v2mux ! filesink location=cd.mp3
rips all tracks from compact disc and convert them into a single mp3 file

        gst-launch cdparanoiasrc track=5 ! audioconvert ! lame ! id3v2mux ! filesink location=track5.mp3
rips track 5 from the CD and converts it into a single mp3 file

Using gst-inspect(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-0.10 will find an element (such as cdparanoia) that supports that protocol for you, e.g.:
       gst-launch cdda://5 ! lame vbr=new vbr-quality=6 ! filesink location=track5.mp3

        gst-launch osssrc ! audioconvert ! vorbisenc ! oggmux ! filesink location=input.ogg
records sound from your audio input and encodes it into an ogg file

Video

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

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

        gst-launch filesrc location=movie.mpg ! dvddemux name=demuxer  demuxer. ! queue ! mpeg2dec ! sdlvideosink  demuxer. ! queue ! mad ! audioconvert ! audioresample ! osssink
Play both video and audio portions of an MPEG movie

        gst-launch filesrc location=movie.mpg ! mpegdemux name=demuxer  demuxer. ! queue ! mpeg2dec ! ffmpegcolorspace ! sdlvideosink   demuxer. ! queue ! mad ! audioconvert ! audioresample ! osssink
Play an AVI movie with an external text subtitle stream

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 textoverlay name=overlay ! ffmpegcolorspace ! videoscale ! autovideosink   filesrc location=movie.avi ! decodebin2 ! ffmpegcolorspace ! overlay.video_sink   filesrc location=movie.srt ! subparse ! overlay.text_sink

Play an AVI movie with an external text subtitle stream using playbin2

        gst-launch playbin2 uri=file:///path/to/movie.avi suburi=file:///path/to/movie.srt

Network streaming

Stream video using RTP and network elements.

        gst-launch v4l2src ! video/x-raw-yuv,width=128,height=96,format='(fourcc)'UYVY ! ffmpegcolorspace ! ffenc_h263 ! video/x-h263 ! rtph263ppay pt=96 ! udpsink host=192.168.1.1 port=5000 sync=false
This command would be run on the transmitter

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

Diagnostic

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

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

        gst-launch videotestsrc ! xvimagesink

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

Automatic linking

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

        gst-launch filesrc location=musicfile ! decodebin ! audioconvert ! audioresample ! osssink
Play any supported audio format

        gst-launch filesrc location=videofile ! decodebin name=decoder  decoder. ! queue ! audioconvert ! audioresample ! osssink   decoder. ! ffmpegcolorspace ! xvimagesink
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 playbin uri=file:///home/joe/foo.avi

Filtered connections

These examples show you how to use filtered caps.

        gst-launch videotestsrc ! 'video/x-raw-yuv,format=(fourcc)YUY2;video/x-raw-yuv,format=(fourcc)YV12' ! xvimagesink
Show a test image and use the YUY2 or YV12 video format for this.

        gst-launch osssrc ! 'audio/x-raw-int,rate=[32000,64000],width=[16,32],depth={16,24,32},signed=(boolean)true' ! wavenc ! filesink location=recording.wav
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.

FILES

~/.gstreamer-0.10/registry-*.xml

The xml plugin database; can be deleted at any time, will be re-created automatically when it does not exist yet or plugins change.

AUTHOR

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