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.
Use --gst-debug-help to show category names
Example: GST_CAT:5,GST_ELEMENT_*:3,oggdemux:5
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 ...] )
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.
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.