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tools: gst-launch: improve content and formatting

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# gst-launch-1.0 # gst-launch-1.0
> ![information] This is the Linux man page for > ![information] This content comes mostly from the Linux man page for
> the `gst-launch-1.0` tool. As such, it is very Linux-centric > the `gst-launch-1.0` tool. As such, it is very Linux-centric
> regarding path specification and plugin names. Please be patient while > regarding path specification and plugin names. Please be patient while
> it is rewritten to be more generic. > it is rewritten to be more generic.
## Name ## Name
gst-launch-1.0 - build and run a GStreamer pipeline `gst-launch-1.0` - build and run a GStreamer pipeline
## Synopsis ## Synopsis
**gst-launch-1.0** *\[OPTION...\]* PIPELINE-DESCRIPTION ```
gst-launch-1.0 [OPTIONS] PIPELINE-DESCRIPTION
```
## Description ## Description
*gst-launch-1.0* is a tool that builds and runs `gst-launch-1.0` is a tool that builds and runs basic *GStreamer* pipelines.
basic *GStreamer* pipelines.
In simple form, a PIPELINE-DESCRIPTION is a list of elements separated In its simplest form, a PIPELINE-DESCRIPTION is a list of elements separated
by exclamation marks (!). Properties may be appended to elements, in the by exclamation marks (!). Properties may be appended to elements in the
form*property=value*. form `property=value`.
For a complete description of possible PIPELINE-DESCRIPTIONS see the For a more complete description of possible PIPELINE-DESCRIPTIONS see the
section*pipeline description* below or consult the GStreamer section *pipeline description* below or consult the GStreamer documentation.
documentation.
Please note that *gst-launch-1.0* is primarily a debugging tool for Please note that `gst-launch-1.0` is primarily a debugging tool. You should
developers and users. You should not build applications on top of it. not build applications on top of it. For applications, use the
For applications, use the gst\_parse\_launch() function of the GStreamer `gst_parse_launch()` function of the GStreamer API as an easy way to construct
API as an easy way to construct pipelines from pipeline descriptions. pipelines from pipeline descriptions.
## Options ## Options
@ -68,300 +68,411 @@ Do not install a fault handler
Print memory allocation traces. The feature must be enabled at compile Print memory allocation traces. The feature must be enabled at compile
time to work. time to work.
 
## Gstreamer Options ## Gstreamer Options
*gst-launch-1.0* also accepts the following options that are common to `gst-launch-1.0` also accepts the following options that are common to
all GStreamer applications: all GStreamer applications:
## Pipeline Description ## Pipeline Description
A pipeline consists *elements* and *links*. *Elements* can be put A pipeline consists *elements* and *links*. *elements* can be put
into *bins* of different sorts. *Elements*, *links* and *bins* can be into *bins* of different sorts. *elements*, *links* and *bins* can be
specified in a pipeline description in any order. specified in a pipeline description in any order.
**Elements** ### Elements
ELEMENTTYPE *\[PROPERTY1 ...\]* ```
ELEMENTTYPE [PROPERTY1 ...]
```
Creates an element of type ELEMENTTYPE and sets the PROPERTIES. Creates an element of type `ELEMENTTYPE` and sets its `PROPERTIES`.
**Properties** ### Element Properties
```
PROPERTY=VALUE ... PROPERTY=VALUE ...
```
Sets the property to the specified value. You can Sets the property to the specified value. You can use `gst-inspect-1.0` to find
use **gst-inspect-1.0**(1) to find out about properties and allowed out about properties and allowed values of different elements. Enumeration
values of different elements. Enumeration properties can be set by name, properties can be set by name, nick or value.
nick or value.
**Bins** ### Bins
*\[BINTYPE.\]* ( *\[PROPERTY1 ...\]* PIPELINE-DESCRIPTION ) ```
[BINTYPE.] ([PROPERTY1 ...] PIPELINE-DESCRIPTION)
```
Specifies that a bin of type BINTYPE is created and the given properties 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 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 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 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 using the `gst_parse_launch()` API with 'bin' as bintype. That way it is
possible to build partial pipelines instead of a full-fledged top-level possible to build partial pipelines instead of a full-fledged top-level
pipeline. pipeline.
**Links** ### Links
*\[\[SRCELEMENT\].\[PAD1,...\]\]* ! *\[\[SINKELEMENT\].\[PAD1,...\]\] ```
\[\[SRCELEMENT\].\[PAD1,...\]\]* ! CAPS [[SRCELEMENT\].[PAD1,...]] ! [[SINKELEMENT].[PAD1,...]]
! *\[\[SINKELEMENT\].\[PAD1,...\]\]* ```
Links the element with name SRCELEMENT to the element with name Links the element with name SRCELEMENT to the element with name SINKELEMENT.
SINKELEMENT, using the caps specified in CAPS as a filter. Names can be Names can be set on elements using the `name` property. If the name is omitted,
set on elements with the name property. If the name is omitted, the the element that was specified directly in front of or after the link is
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 using that
used. This works across bins. If a padname is given, the link is done pad. If no pad names are given all possibilities are tried and a compatible pad
with these pads. If no pad names are given all possibilities are tried is used. If multiple padnames are given, both sides must have the same number of
and a matching pad is used. If multiple padnames are given, both sides pads specified and multiple links are done in the given order. The simplest link
must have the same number of pads specified and multiple links are done is a simple exclamation mark. This links the element to the left of it with the
in the given order. So the simplest link is a simple exclamation mark, element at its right.
that links the element to the left of it to the element right of it.
**Caps**
MIMETYPE *\[, PROPERTY\[, PROPERTY ...\]\]\] \[; CAPS\[; CAPS ...\]\]* The following links the element with name SRCELEMENT to the element with name
SINKELEMENT, using the caps specified in CAPS as a filter:
```
[[SRCELEMENT].[PAD1,...]] ! CAPS ! [[SINKELEMENT].[PAD1,...]]
```
### Caps
```
MIMETYPE [, PROPERTY[, PROPERTY ...]]] [; CAPS[; CAPS ...]]
```
Creates a capability with the given mimetype and optionally with given Creates a capability with the given mimetype and optionally with given
properties. The mimetype can be escaped using " or '. If you want to properties. The mimetype can be escaped using `"` or `'`. If you want to
chain caps, you can add more caps in the same format afterwards. chain caps, you can add more caps in the same format afterwards.
**Properties** ### Caps Properties
NAME=*\[(TYPE)\]*VALUE in lists and ranges: *\[(TYPE)\]*VALUE ```
NAME=[(TYPE)] VALUE in lists and ranges: [(TYPE)] VALUE
```
Sets the requested property in capabilities. The name is an alphanumeric Sets the requested property in capabilities. The name is an alphanumeric
value and the type can have the following case-insensitive values: value and the type can have the following case-insensitive values:
- **i** or **int** for integer values or ranges - **f** or **float** for - **i** or **int** for integer values or ranges - **f** or **float** for
float values or ranges - **4** or **fourcc** for FOURCC values float values or ranges - **4** or **fourcc** for FOURCC values
- **b**, **bool** or **boolean** for boolean values - **b**, **bool** or **boolean** for boolean values
- **s**, **str** or **string** for strings - **fraction** for fractions - **s**, **str** or **string** for strings - **fraction** for fractions
(framerate, pixel-aspect-ratio) - **l** or **list** for lists If no type (framerate, pixel-aspect-ratio)
was given, the following order is tried: integer, float, boolean, - **l** or **list** for lists If no type was given, the following order is
string. Integer values must be parsable by **strtol()**, floats tried: integer, float, boolean, string. Integer values must be parsable by
by **strtod()**. FOURCC values may either be integers or strings. **strtol()**, floats by **strtod()**. FOURCC values may either be integers or
Boolean values are (case insensitive) *yes*, *no*, *true* or *false* and strings. Boolean values are (case insensitive) *yes*, *no*, *true* or *false*
may like strings be escaped with " or '. Ranges are in this format: \[ and may like strings be escaped with `"` or `'`. Ranges are in this format: `[
VALUE, VALUE \] Lists use this format: ( VALUE *\[, VALUE ...\]* ) VALUE, VALUE] Lists use this format: (VALUE [, VALUE ...])`
## Pipeline Control ## Pipeline Control
A pipeline can be controlled by signals. SIGUSR2 will stop the pipeline A pipeline can be controlled by signals. `SIGUSR2` will stop the pipeline
(GST\_STATE\_NULL); SIGUSR1 will put it back to play (`GST_STATE_NULL`); `SIGUSR1` will put it back to play (`GST_STATE_PLAYING`). By
(GST\_STATE\_PLAYING). By default, the pipeline will start in the default, the pipeline will start in the `PLAYING` state. There are currently no
playing state. There are currently no signals defined to go into the signals defined to go into the ready or pause (`GST_STATE_READY` and `GST_STATE_PAUSED`) states explicitly.
ready or pause (GST\_STATE\_READY and GST\_STATE\_PAUSED) state
explicitely.
## Pipeline Examples ## Pipeline Examples
The examples below assume that you have the correct plug-ins available. The examples below assume that you have the correct plugins available.
In general, "osssink" can be substituted with another audio output In general, `osssink` can be substituted with another audio output
plug-in such as "directsoundsink", "esdsink", "alsasink", plugin such as `directsoundsink`, `esdsink`, `alsasink`, `osxaudiosink`, or
"osxaudiosink", or "artsdsink". Likewise, "xvimagesink" can be `artsdsink`. Likewise, `xvimagesink` can be substituted with `d3dvideosink`,
substituted with "d3dvideosink", "ximagesink", "sdlvideosink", `ximagesink`, `sdlvideosink`, `osxvideosink`, or `aasink`. Keep in mind though
"osxvideosink", or "aasink". Keep in mind though that different sinks that different sinks might accept different formats and even the same sink might
might accept different formats and even the same sink might accept accept different formats on different machines, so you might need to add
different formats on different machines, so you might need to add converter elements like `audioconvert` and `audioresample` for audio or
converter elements like audioconvert and audioresample (for audio) or `videoconvert` in front of the sink to make things work.
videoconvert (for video) in front of the sink to make things work.
**Audio playback** ### Audio playback
`gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! Play the mp3 music file "music.mp3" using a libmad-based plugin and output to
audioresample ! osssink` Play the mp3 music file "music.mp3" using a an OSS device:
libmad-based plug-in and output to an OSS device
`gst-launch-1.0 filesrc location=music.ogg ! oggdemux ! vorbisdec ! ```
audioconvert ! audioresample ! osssink` Play an Ogg Vorbis format file gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert !
audioresample ! osssink
```
`gst-launch-1.0 gnomevfssrc location=music.mp3 ! mad ! osssink Play an Ogg Vorbis format file:
```
gst-launch-1.0 filesrc location=music.ogg ! oggdemux ! vorbisdec !
audioconvert ! audioresample ! osssink
```
Play an mp3 file using GNOME-VFS:
```
gst-launch-1.0 gnomevfssrc location=music.mp3 ! mad ! osssink
```
Play an HTTP stream using GNOME-VFS:
```
gst-launch-1.0 gnomevfssrc location=<http://domain.com/music.mp3> ! mad gst-launch-1.0 gnomevfssrc location=<http://domain.com/music.mp3> ! mad
! audioconvert ! audioresample ! osssink` Play an mp3 file or an http ! audioconvert ! audioresample ! osssink
stream using GNOME-VFS ```
`gst-launch-1.0 gnomevfssrc location=<smb://computer/music.mp3> ! mad ! Use GNOME-VFS to play an mp3 file located on an SMB server:
audioconvert ! audioresample ! osssink` Use GNOME-VFS to play an mp3
file located on an SMB server
**Format conversion** ```
gst-launch-1.0 gnomevfssrc location=<smb://computer/music.mp3> ! mad !
audioconvert ! audioresample ! osssink
```
`gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! ### Format conversion
vorbisenc ! oggmux ! filesink location=music.ogg` Convert an mp3 music
file to an Ogg Vorbis file
`gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! Convert an mp3 music file to an Ogg Vorbis file:
flacenc ! filesink location=test.flac` Convert to the FLAC format
**Other** ```
gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! vorbisenc !
oggmux ! filesink location=music.ogg
```
`gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! Convert to the FLAC format:
audioresample ! osssink` Plays a .WAV file that contains raw audio data
(PCM).
`gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! ```
vorbisenc ! oggmux ! filesink location=music.ogg gst-launch-1.0 filesrc gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! flacenc !
location=music.wav ! wavparse ! audioconvert ! lame ! filesink filesink location=test.flac`
location=music.mp3` Convert a .WAV file containing raw audio data into ```
an Ogg Vorbis or mp3 file
`gst-launch-1.0 cdparanoiasrc mode=continuous ! audioconvert ! lame ! ### Other
id3v2mux ! filesink location=cd.mp3` rips all tracks from compact disc
and convert them into a single mp3 file
`gst-launch-1.0 cdparanoiasrc track=5 ! audioconvert ! lame ! id3v2mux Play a .WAV file that contains raw audio data (PCM):
! filesink location=track5.mp3` rips track 5 from the CD and converts
it into a single mp3 file
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 gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert !
only tracks of it. Alternatively, you can use an URI and gst-launch-1.0 audioresample ! osssink
```
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 ! lame !
filesink location=music.mp3
```
Rip all tracks from CD and convert them into a single mp3 file:
```
gst-launch-1.0 cdparanoiasrc mode=continuous ! audioconvert ! lame !
id3v2mux ! filesink location=cd.mp3
```
Rip track 5 from the CD and converts it into a single mp3 file:
```
gst-launch-1.0 cdparanoiasrc track=5 ! audioconvert ! lame ! id3v2mux
! filesink location=track5.mp3
```
Using `gst-inspect-1.0`, 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 will find an element (such as cdparanoia) that supports that protocol
for you, e.g.: `gst-launch-1.0 \[cdda://5\] ! lame vbr=new for you, e.g.: 
vbr-quality=6 ! filesink location=track5.mp3`
`gst-launch-1.0 osssrc ! audioconvert ! vorbisenc ! oggmux ! filesink ```
location=input.ogg` records sound from your audio input and encodes it gst-launch-1.0 [cdda://5] ! lame vbr=new vbr-quality=6 !
into an ogg file filesink location=track5.mp3
```
**Video** Record sound from your audio input and encode it into an ogg file:
`gst-launch-1.0 filesrc location=JB\_FF9\_TheGravityOfLove.mpg ! ```
dvddemux ! mpeg2dec ! xvimagesink` Display only the video portion of an gst-launch-1.0 osssrc ! audioconvert ! vorbisenc ! oggmux !
MPEG-1 video file, outputting to an X display window filesink location=input.ogg
```
`gst-launch-1.0 filesrc location=/flflfj.vob ! dvddemux ! mpeg2dec ! ### Video
sdlvideosink` Display the video portion of a .vob file (used on DVDs),
outputting to an SDL window
`gst-launch-1.0 filesrc location=movie.mpg ! dvddemux name=demuxer Display only the video portion of an MPEG-1 video file, outputting to an X
demuxer. ! queue ! mpeg2dec ! sdlvideosink demuxer. ! queue ! mad ! display window:
audioconvert ! audioresample ! osssink` Play both video and audio
portions of an MPEG movie
`gst-launch-1.0 filesrc location=movie.mpg ! mpegdemux name=demuxer ```
demuxer. ! queue ! mpeg2dec ! videoconvert ! sdlvideosink demuxer. ! gst-launch-1.0 filesrc location=videofile.mpg ! dvddemux ! mpeg2dec !
queue ! mad ! audioconvert ! audioresample ! osssink` Play an AVI movie xvimagesink
with an external text subtitle stream ```
This example also shows how to refer to specific pads by name if an Display the video portion of a .vob file (used on DVDs), outputting to an SDL
element (here: textoverlay) has multiple sink or source pads. window:
`gst-launch-1.0 textoverlay name=overlay ! videoconvert ! ```
videoscale ! autovideosink filesrc location=movie.avi ! decodebin2 ! gst-launch-1.0 filesrc location=flflfj.vob ! dvddemux ! mpeg2dec ! sdlvideosink
videoconvert ! overlay.video\_sink filesrc location=movie.srt ! ```
subparse ! overlay.text\_sink`
Play an AVI movie with an external text subtitle stream using playbin Play both video and audio portions of an MPEG movie:
`gst-launch-1.0 playbin uri=<file:///path/to/movie.avi> ```
suburi=<file:///path/to/movie.srt>` gst-launch-1.0 filesrc location=movie.mpg ! dvddemux name=demuxer
demuxer. ! queue ! mpeg2dec ! sdlvideosink
demuxer. ! queue ! mad ! audioconvert ! audioresample ! osssink
```
**Network streaming** Play an AVI movie with an external text subtitle stream:
Stream video using RTP and network elements. ```
gst-launch-1.0 filesrc location=movie.mpg ! mpegdemux name=demuxer
demuxer. ! queue ! mpeg2dec ! videoconvert ! sdlvideosink
demuxer. ! queue ! mad ! audioconvert ! audioresample ! osssink
```
`gst-launch-1.0 v4l2src ! This example 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 ! decodebin2 ! 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-yuv,width=128,height=96,format='(fourcc)'UYVY ! video/x-raw-yuv,width=128,height=96,format='(fourcc)'UYVY !
videoconvert ! ffenc\_h263 ! video/x-h263 ! rtph263ppay pt=96 ! videoconvert ! ffenc_h263 ! video/x-h263 ! rtph263ppay pt=96 !
udpsink host=192.168.1.1 port=5000 sync=false` Use this command on the udpsink host=192.168.1.1 port=5000 sync=false
receiver ```
`gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, Use this command on the receiver:
clock-rate=90000,payload=96 ! rtph263pdepay queue-delay=0 ! ffdec\_h263
! xvimagesink` This command would be run on the transmitter
**Diagnostic** ```
gst-launch-1.0 udpsrc port=5000 ! application/x-rtp,
clock-rate=90000,payload=96 ! rtph263pdepay queue-delay=0 ! ffdec_h263
! xvimagesink
```
`gst-launch-1.0 -v fakesrc num-buffers=16 ! fakesink` Generate a null ### Diagnostic
stream and ignore it (and print out details).
`gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! osssink` Generate a null stream and ignore it (and print out details):
Generate a pure sine tone to test the audio output
`gst-launch-1.0 videotestsrc ! xvimagesink gst-launch-1.0 videotestsrc ```
! ximagesink` Generate a familiar test pattern to test the video output gst-launch-1.0 -v fakesrc num-buffers=16 ! fakesink
```
**Automatic linking** Generate a pure sine tone to test the audio output:
```
gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! osssink
```
Generate a familiar test pattern to test the video output:
```
gst-launch-1.0 videotestsrc ! ximagesink
```
### Automatic linking
You can use the decodebin element to automatically select the right You can use the decodebin element to automatically select the right
elements to get a working pipeline. elements to get a working pipeline.
`gst-launch-1.0 filesrc location=musicfile ! decodebin ! audioconvert ! Play any supported audio format:
audioresample ! osssink` Play any supported audio format
`gst-launch-1.0 filesrc location=videofile ! decodebin name=decoder ```
decoder. ! queue ! audioconvert ! audioresample ! osssink decoder. ! gst-launch-1.0 filesrc location=musicfile ! decodebin ! audioconvert !
videoconvert ! xvimagesink` Play any supported video format with audioresample ! osssink
video and audio output. Threads are used automatically. To make this ```
even easier, you can use the playbin element:
`gst-launch-1.0 playbin uri=<file:///home/joe/foo.avi>` Play any supported video format with video and audio output. Threads are used
automatically:
**Filtered connections** ```
gst-launch-1.0 filesrc location=videofile ! decodebin name=decoder
decoder. ! queue ! audioconvert ! audioresample ! osssink
decoder. ! videoconvert ! xvimagesink
```
To make the above even easier, you can use the playbin element:
```
gst-launch-1.0 playbin uri=<file:///home/joe/foo.avi>
```
### Filtered connections
These examples show you how to use filtered caps. These examples show you how to use filtered caps.
`gst-launch-1.0 videotestsrc ! Show a test image and use the YUY2 or YV12 video format for this:
'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-1.0 osssrc ! ```
'audio/x-raw-int,rate=\[32000,64000\],width=\[16,32\],depth={16,24,32},signed=(boolean)true' gst-launch-1.0 videotestsrc !
! wavenc ! filesink location=recording.wav` record audio and write it 'video/x-raw-yuv,format=(fourcc)YUY2;video/x-raw-yuv,format=(fourcc)YV12'
to a .wav file. Force usage of signed 16 to 32 bit samples and a sample ! xvimagesink
rate between 32kHz and 64KHz. ```
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 osssrc !
'audio/x-raw-int,rate=[32000,64000],width=[16,32],depth={16,24,32},signed=(boolean)true'
! wavenc ! filesink location=recording.wav
```
## Environment Variables ## Environment Variables
`GST\_DEBUG`: Comma-separated list of debug categories and levels, `GST_DEBUG`: Comma-separated list of debug categories and levels, e.g:
e.g. GST\_DEBUG= totem:4,typefind:5
`GST\_DEBUG\_NO\_COLOR`: When this environment variable is set, ```
coloured debug output is disabled. GST_DEBUG=totem:4,typefind:5
```
`GST\_DEBUG\_DUMP\_DOT\_DIR`: When set to a filesystem path, store dot `GST_DEBUG_NO_COLOR`: When this environment variable is set, coloured debug
output is disabled. This might come handy when saving the debug output to a
file.
`GST_DEBUG_DUMP_DOT_DIR`: When set to a filesystem path, store dot
files of pipeline graphs there. files of pipeline graphs there.
`GST\_REGISTRY`: Path of the plugin registry file. Default is `GST_REGISTRY`: Path of the plugin registry file. The default is
\~/.gstreamer-1.0/registry-CPU.xml where CPU is the machine/cpu type `~/.gstreamer-1.0/registry-CPU.xml` where CPU is the machine/cpu type
GStreamer was compiled for, e.g. 'i486', 'i686', 'x86-64', 'ppc', etc. GStreamer was compiled for, e.g. 'i486', 'i686', 'x86-64', 'ppc', etc.
(check the output of "uname -i" and "uname -m" for details). Check the output of `uname -i` and `uname -m` for details.
`GST\_REGISTRY\_UPDATE`: Set to "no" to force GStreamer to assume that `GST_REGISTRY_UPDATE`: Set to "no" to force GStreamer to assume that no plugins
no plugins have changed, been added or been removed. This will make have changed, have been added or have been removed. This will make GStreamer
GStreamer skip the initial check whether a rebuild of the registry cache skip the initial check to determine whether a rebuild of the registry cache is
is required or not. This may be useful in embedded environments where required or not. This may be useful in embedded environments where the installed
the installed plugins never change. Do not use this option in any other plugins never change. Do not use this option in any other setup.
setup.
`GST\_PLUGIN\_PATH`: Specifies a list of directories to scan for `GST_PLUGIN_PATH`: Specifies a list of directories to scan for additional
additional plugins. These take precedence over the system plugins. plugins. These take precedence over the system plugins.
`GST\_PLUGIN\_SYSTEM\_PATH`: Specifies a list of plugins that are `GST_PLUGIN_SYSTEM_PATH`: Specifies a list of plugins that are always loaded by
always loaded by default. If not set, this defaults to the default. If not set, this defaults to the system-installed path, and the plugins
system-installed path, and the plugins installed in the user's home installed in the user's home directory
directory
`OIL\_CPU\_FLAGS`: Useful liboil environment variable. Set `OIL_CPU_FLAGS`: Useful liboil environment variable. Set `OIL_CPU_FLAGS=0` when
OIL\_CPU\_FLAGS=0 when valgrind or other debugging tools trip over valgrind or other debugging tools trip over liboil's CPU detection. Quite a few
liboil's CPU detection (quite a few important GStreamer plugins like important GStreamer plugins like `videotestsrc`, `audioconvert` and
videotestsrc, audioconvert or audioresample use liboil). `audioresample` use liboil.
`G\_DEBUG`: Useful GLib environment variable. Set `G_DEBUG`: This is a useful GLib environment variable. Set
G\_DEBUG=fatal\_warnings to make GStreamer programs abort when a `G_DEBUG=fatal_warnings` to make GStreamer programs abort when a critical
critical warning such as an assertion failure occurs. This is useful if warning such as an assertion failure occurs. This is useful if you want to find
you want to find out which part of the code caused that warning to be out which part of the code caused that warning to be triggered and under what
triggered and under what circumstances. Simply set G\_DEBUG as mentioned circumstances. Simply set `G_DEBUG` as mentioned above and run the program under
above and run the program in gdb (or let it core dump). Then get a stack gdb (or let it core dump). Then get a stack trace in the usual way.
trace in the usual way
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