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gst-launch-0.8(1) |
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gst−launch − build and run a GStreamer pipeline
gst−launch [OPTION...] PIPELINE−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 above under pipeline description or the GStreamer documentation.
gst−launch accepts the following options:
|
−−help |
Print help synopsis and available FLAGS |
−v, −−silent
Output status information
−XTYPE, −−exclude=TYPE,
Do not output status information of TYPE
−oFILE, −−output=FILE
Save XML representation of pipeline to FILE and exit
−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.
−i, −−iterations=N
Stop processing after N iterations.
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.
−−gst−debug=STRING
A colon seperated 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
−−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.
−−gst−disable−debug
Disables debugging.
−−gst−debug−help
Prints a list of available debug categories and their default debugging level.
−−gst−disable−cpu−opt
GStreamer normally automatically detects the capabilities of the current CPU and selects the optimal implementation for some functions. Using this flag disables detection, which is useful for debugging.
−−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
−−gst−scheduler=SCHEDULER
Use SCHEDULER as the default scheduler
−−gst−registry=REGISTRY
Use the file REGISTRY as registry instead of the default
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 )
{ [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. Using curly braces (second line) is a short cut for
using the first line and "thread" as the BINTYPE.
Please not the dot that has to be used after the
BINTYPE.
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.
Note that when specifying either pads or element names you
have to include the dot or your syntax will be
misinterpreted. This is a change to the old syntax used up
to version 0.6 that allowed omitting the dot when only
specifying a padname.
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 capabilites. 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
- 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: [ PROPERTY, PROPERTY ]
Lists use this format: ( PROPERTY [, PROPERTY ...]
)
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
explicitely.
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", or "artsdsink". Likewise, "xvideosink" can be substituted with "sdlvideosink" or "aasink".
Audio playback
gst−launch
filesrc location=music.mp3 ! mad ! 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 ! 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 ! osssink
Play an mp3 file or an http stream using GNOME−VFS
gst−launch
gnomevfssrc location=smb://computer/music.mp3 ! mad !
osssink
Use GNOME−VFS to play an mp3 file located on an SMB
server
Format conversion
gst−launch
filesrc location=music.mp3 ! mad ! vorbisenc ! filesink
location=music.ogg
Convert an mp3 music file to an Ogg Vorbis file
gst−launch
filesrc location=music.mp3 ! mad ! flacenc ! filesink
location=test.flac
Convert to the FLAC format
Other
gst−launch
filesrc location=music.wav ! wavparse ! osssink
Plays a .WAV file
gst−launch
filesrc location=music.wav ! wavparse ! vorbisenc ! filesink
location=music.ogg
gst−launch filesrc location=music.wav ! wavparse !
mpegaudio ! filesink location=music.mp3
Convert a .WAV file into Ogg Vorbis (or mp3) file
Alternatively, if you have lame installed (and have the lame plug-in), you can substitute lame for mpegaudio in the previous example. It gives better results than mpegaudio.
gst−launch
cdparanoia ! mpegaudio ! filesink location=cd.mp3
Rip all tracks from compact disc and convert them into a
single mp3 file
Using gst−inspect(1), it is possible to discover settings for cdparanoia that will tell it to rip individual tracks.
gst−launch
osssrc ! vorbisenc ! filesink location=input.ogg
Record sound from your audio input and encode it into an ogg
file
Video
gst−launch
filesrc location=JB_FF9_TheGravityOfLove.mpg ! mpegdemux !
mpeg2dec ! xvideosink
Display only the video portion of an MPEG-1 video file,
outputting to an X display window
gst−launch
filesrc location=/flflfj.vob ! mpegdemux ! mpeg2dec !
sdlvideosink
Display the video portion of a .vob file (used on DVDs),
outputting to an SDL window
gst−launch
filesrc location=movie.mpg ! mpegdemux name=demuxer !
mpeg2dec ! sdlvideosink demuxer. ! mad ! osssink
Play both video and audio portions of an MPEG movie
gst−launch
filesrc location=movie.mpg ! mpegdemux name=demuxer ! {
queue ! mpeg2dec ! sdlvideosink } { demuxer. ! queue ! mad !
osssink }
Use threaded output to improve synchronization and
smoothness. Threads require queues for buffering on thread
boundaries
gst−launch
filesrc location=movie.avi ! avidemux name=demuxer ! { queue
! ffdecall ! sdlvideosink } { demuxer. ! queue ! mad !
osssink }
Play an AVI movie
Network streaming
An MPEG−1 system stream can be streamed via RTP from one machine to another.
gst−launch
rtprecv media_type=mpeg1_sys ! mpegdemux name=demuxer ! {
queue ! mpeg2dec ! xvideosink } { demuxer. ! queue ! mad !
osssink }
Use this command on the receiver
gst−launch
filesrc location=mpeg1system.mpeg ! mpegparse ! rtpsend
ip=IPorHostname
This command would be run on the transmitter
Diagnostic
gst−launch
fakesrc ! fakesink
Generate a null stream and ignore it
gst−launch
sinesrc ! osssink
Generate a pure tone to test the audio output
gst−launch
videotestsrc ! xvideosink
Generate a familiar test pattern to test the video
output
Automatic linking
You can use the spider element to automatically select the right elements to get a working pipeline.
gst−launch
filesrc location=musicfile ! spider ! osssink
Play any supported audio format
gst−launch
filesrc location=videofile ! spider name=spider ! osssink
spider. ! xvideosink
gst−launch filesrc location=videofile ! spider
name=spider ! { queue ! osssink } { spider. ! queue !
xvideosink }
Play any supported video format with video and audio output.
The second pipeline uses threaded output.
Filtered connections
These examples show you how to use filtered caps.
gst−launch
videotestsrc ! video/raw, format:fourcc=YUY2; video/raw,
format:fourcc=YV12 ! xvideosink
Show a test image and use the YUY2 or YV12 video format for
this.
gst−launch
osssrc ! "audio/raw", format=int, width=[16, 32],
depth=(16, 24, 32), signed=TRUE ! osssink
Playback currently recorded audio. Force usage of signed 16
to 32 bit samples.
gst−complete(1), gst−register(1), gst−inspect(1)
The GStreamer team at http://gstreamer.net/
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gst-launch-0.8(1) | |