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This still had the content from 0.10 time. See https://gitlab.freedesktop.org/gstreamer/gst-docs/-/issues/108 Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7859>
607 lines
20 KiB
Markdown
607 lines
20 KiB
Markdown
# gst-launch-1.0
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> ![information] This content comes mostly from the Linux man page for
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> the `gst-launch-1.0` tool. As such, it is very Linux-centric
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> regarding path specification and plugin names. Please be patient while
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> it is rewritten to be more generic.
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## Name
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`gst-launch-1.0` - build and run a GStreamer pipeline
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## Synopsis
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```
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gst-launch-1.0 [OPTIONS] PIPELINE-DESCRIPTION
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```
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## Description
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`gst-launch-1.0` is a tool that builds and runs basic *GStreamer* pipelines.
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In its simplest form, a PIPELINE-DESCRIPTION is a list of elements separated
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by exclamation marks (!). Properties may be appended to elements in the
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form `property=value`. A "preset" can also be set using
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the `@preset=<preset name>` syntax.
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For a more complete description of possible PIPELINE-DESCRIPTIONS see the
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section [Pipeline Description](#pipeline-description) below or consult the
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GStreamer documentation.
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Please note that `gst-launch-1.0` is primarily a debugging tool. You should
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not build applications on top of it. For applications, write a little python
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script or Rust application (or use whatever other programming language you
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prefer) and use the `gst_parse_launch()` function of the GStreamer API as an
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easy way to construct pipelines from pipeline descriptions.
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## Options
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*gst-launch-1.0* accepts the following options:
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**--help**
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Print help synopsis and available FLAGS
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**-v, --verbose**
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Output status information and property notifications
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**-q, --quiet**
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Do not print any progress information
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**-m, --messages**
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Output messages posted on the pipeline's bus
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**-t, --tags**
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Output tags (also known as metadata)
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**-e, --eos-on-shutdown**
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Force an EOS event on sources before shutting the pipeline down. This is
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useful to make sure muxers create readable files when a muxing pipeline is
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shut down forcefully via Control-C (especially in case of `mp4mux` and `qtmux`
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where the created file will be unreadable if the file has not been finalised
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properly).
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**-f, --no\_fault**
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Do not install a segfault handler
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**--no-position**
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Do not print the current position of pipeline.
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If this option is unspecified, the position will be printed when stdout is a TTY.
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To enable printing position when stdout is not a TTY,
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use the "--force-position" option.
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**--force-position**
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Allow printing the current position of pipeline even if stdout is not a TTY.
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This option has no effect if the "--no-position" option is specified.
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## GStreamer Options
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`gst-launch-1.0` also accepts the following options that are common to
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all GStreamer applications:
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**--gst-version**
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Prints the version string of the `GStreamer` core library.
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**--gst-fatal-warnings**
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Causes `GStreamer` to abort if a warning message occurs. This is equivalent
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to setting the environment variable `G_DEBUG=fatal_warnings` (see the
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section `environment variables` below for further information).
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**--gst-debug=STRING**
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A comma separated list of `category_name:level` pairs to specify debugging levels
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for each category. Level is in the range 0-9 where 0 will show no messages, and
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9 will show all messages. The wildcard `*` can be used to match category names.
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Note that the order of categories and levels is important, wildcards at the
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end may override levels set earlier. The log levels are:
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1. ERROR
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2. WARNING
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3. FIXME
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4. INFO
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5. DEBUG
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6. LOG (this is the highest 'normal' debug level)
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7. TRACE
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9. MEMDUMP
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Since GStreamer 1.2 one can also use the debug level names, e.g.
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`--gst-debug=*sink:LOG`. A full description of the various debug levels
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can be found in the GStreamer core library API documentation, in the
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"Running GStreamer Applications" section.
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Use `--gst-debug-help` to show category names
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Example: `GST_CAT:LOG,GST_ELEMENT_*:INFO,oggdemux:LOG`
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**--gst-debug-level=LEVEL**
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Sets the threshold for printing debugging messages. A higher level
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will print more messages. The useful range is 0-9, with the default
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being 0. Level 6 (LOG level) will show all information that is usually
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required for debugging purposes. Higher levels are only useful in very
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specific cases. See above for the full list of levels.
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**--gst-debug-no-color**
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`GStreamer` normally prints debugging messages so that the
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messages are color-coded when printed to a terminal that handles
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ANSI escape sequences. Using this option causes GStreamer
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to print messages without color. Setting the `GST_DEBUG_NO_COLOR=1`
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environment variable will achieve the same thing.
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**--gst-debug-color-mode**
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GStreamer normally prints debugging messages so that the
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messages are color-coded when printed to a terminal that handles
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ANSI escape sequences (on *nix), or uses W32 console API to color the
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messages printed into a console (on W32). Using this option causes
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GStreamer to print messages without color ('off' or 'disable'),
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print messages with default colors ('on' or 'auto'), or print messages
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using ANSI escape sequences for coloring ('unix'). Setting the
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`GST_DEBUG_COLOR_MODE` environment variable will achieve the same thing.
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**--gst-debug-disable**
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Disables debugging.
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**--gst-debug-help**
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Prints a list of available debug categories and their default debugging level.
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**--gst-plugin-path=PATH**
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Add directories separated with `:` (`;` on Windows) to the plugin search path.
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**--gst-plugin-load=PLUGINS**
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Preload plugins specified in a comma-separated list. Another way to specify
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plugins to preload is to use the environment variable `GST_PLUGIN_PATH`.
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## Pipeline Description
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A pipeline consists of *elements* and *links*. *Elements* can be put
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into *bins* of different sorts. *Elements*, *links*, and *bins* can be
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specified in a pipeline description in any order.
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### Elements
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```
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ELEMENTTYPE [PROPERTY1 ...]
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```
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Creates an element of type `ELEMENTTYPE` and sets its `PROPERTIES`.
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### Element Properties
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```
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PROPERTY=VALUE ...
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```
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Sets the property to the specified value. You can use `gst-inspect-1.0` to find
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out about properties and allowed values of different elements. Enumeration
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properties can be set by name, nick or value.
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### Element Presets
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```
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@preset=<preset name> ...
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```
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Sets the preset (basically a pre-made collection of property settings for a
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specific element) on the element. you can use `gst-inspect-1.0` to
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find out what presets are available for a specific element.
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### Bins
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```
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[BINTYPE.] ([PROPERTY1 ...] PIPELINE-DESCRIPTION)
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```
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Specifies that a bin of type `BINTYPE` is created and the given properties
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are set. Every element between the braces is put into the bin. Please
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note the dot that has to be used after the `BINTYPE`. You will almost
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never need this functionality, it is only really useful for applications
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using the `gst_parse_launch()` API with `bin` as bintype. That way it is
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possible to build partial pipelines instead of a full-fledged top-level
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pipeline.
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### Links
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```
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[[SRCELEMENT].[PAD1,...]] ! [[SINKELEMENT].[PAD1,...]]
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[[SRCELEMENT].[PAD1,...]] ! CAPS ! [[SINKELEMENT].[PAD1,...]]
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[[SRCELEMENT].[PAD1,...]] : [[SINKELEMENT].[PAD1,...]]
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[[SRCELEMENT].[PAD1,...]] : CAPS : [[SINKELEMENT].[PAD1,...]]
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```
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Links the element with name SRCELEMENT to the element with name SINKELEMENT,
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using the caps specified in CAPS as a filter.
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Names can be set on elements using the `name` property. If the name is omitted,
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the element that was specified directly in front of or after the link is
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used. This works across bins. If a padname is given, the link is done using that
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pad. If no pad names are given all possibilities are tried and a compatible pad
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is used. If multiple padnames are given, both sides must have the same number of
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pads specified and multiple links are done in the given order.
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The simplest link is a simple exclamation mark. This links the element to the
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left of it with the element at its right.
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Linking using the `:` operator attempts to link all possible pads between
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the elements
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The following links the element with name SRCELEMENT to the element with name
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SINKELEMENT, using the caps specified in CAPS as a filter:
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```
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[[SRCELEMENT].[PAD1,...]] ! CAPS ! [[SINKELEMENT].[PAD1,...]]
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```
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### Caps
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```
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MIMETYPE [, PROPERTY[, PROPERTY ...]]] [; CAPS[; CAPS ...]]
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```
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Creates a capability with the given mimetype and optionally with given
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properties. The mimetype can be escaped using `"` or `'`. If you want to
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chain caps, you can add more caps in the same format afterwards.
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### Caps Properties
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```
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NAME=[(TYPE)] VALUE in lists and ranges: [(TYPE)] VALUE
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```
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Sets the requested property in capabilities. The name is an alphanumeric
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value and the type can have the following case-insensitive values:
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- `i` or `int` for integer values or ranges;
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- `f` or `float` for float values or ranges;
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- `b`, `bool`, or `boolean` for boolean values;
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- `s`, `str`, or `string` for strings;
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- `fraction` for fractions (framerate, pixel-aspect-ratio);
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- `l` or `list` for lists.
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If no type was given, the following order is tried: integer, float, boolean,
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string. Integer values must be parsable by `strtol()`, floats by `strtod()`.
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Boolean values are (case insensitive) `yes`, `no`, `true` or `false`
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and may like strings be escaped with `"` or `'`.
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Ranges are in this format: `[VALUE, VALUE]`, e.g. `width=[16,1920]`
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Lists use this format: `{VALUE [, VALUE ...]}`, e.g. `width={1920,1280,640}`
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## Pipeline Examples
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The examples below assume that you have the correct plug-ins available.
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In general, "pulsesink" can be substituted with another audio output
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plug-in such as "alsasink", "osxaudiosink", or "wasapisink"
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Likewise, `xvimagesink` can be substituted with `d3dvideosink`,
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`ximagesink`, `sdlvideosink`, `osxvideosink`, or `aasink`.
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Keep in mind though that different sinks might accept different formats and
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even the same sink might accept different formats on different machines, so
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you might need to add converter elements like `audioconvert` and `audioresample`
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for audio or `videoconvertscale` in front of the sink to make things work.
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### Audio playback
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**Note:** For audio/video playback it's best to use the `playbin3` or
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`uridecodebin3` elements, these are just example pipelines.
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Play the mp3 music file "music.mp3" using a libmpg123-based plug-in and
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output it to an audio device via PulseAudio (or PipeWire).
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```
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gst-launch-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink
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```
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Play an Ogg Vorbis format file:
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```
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gst-launch-1.0 filesrc location=music.ogg ! oggdemux ! vorbisdec ! audioconvert ! audioresample ! pulsesink
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```
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Play an mp3 file or an http stream using GIO:
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```
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gst-launch-1.0 giosrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! pulsesink
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```
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```
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gst-launch-1.0 giosrc location=http://domain.com/music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink
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```
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Use GIO to play an mp3 file located on an SMB server:
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```
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gst-launch-1.0 giosrc location=smb://computer/music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink
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```
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### Format conversion
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Convert an mp3 music file to an Ogg Vorbis file:
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```
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gst-launch-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
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```
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Convert to the FLAC format:
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```
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gst-launch-1.0 filesrc location=music.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! flacenc ! filesink location=test.flac
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```
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### Other
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Play a .WAV file that contains raw audio data (PCM):
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```
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gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! audioresample ! pulsesink
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```
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Convert a .WAV file containing raw audio data into an Ogg Vorbis or mp3 file:
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```
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gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! vorbisenc ! oggmux ! filesink location=music.ogg
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```
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```
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gst-launch-1.0 filesrc location=music.wav ! wavparse ! audioconvert ! lamemp3enc ! xingmux ! id3v2mux ! filesink location=music.mp3
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```
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Rip all tracks from CD and convert them into a single mp3 file:
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```
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gst-launch-1.0 cdparanoiasrc mode=continuous ! audioconvert ! lamemp3enc ! mpegaudioparse ! xingmux ! id3v2mux ! filesink location=cd.mp3
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```
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Rip track 5 from the CD and converts it into a single mp3 file:
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```
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gst-launch-1.0 cdparanoiasrc track=5 ! audioconvert ! lamemp3enc ! mpegaudioparse ! xingmux ! id3v2mux ! filesink location=track5.mp3
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```
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Using `gst-inspect-1.0`, it is possible to discover settings like
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the above for "cdparanoiasrc" that will tell it to rip the entire CD or
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only tracks of it. Alternatively, you can use an URI and `gst-launch-1.0`
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will find an element (such as cdparanoia) that supports that protocol
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for you, e.g.:
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```
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gst-launch-1.0 cdda://5 ! lamemp3enc vbr=new vbr-quality=6 ! xingmux ! id3v2mux ! filesink location=track5.mp3
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```
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Record sound from your audio input and encode it into an ogg file:
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```
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gst-launch-1.0 pulsesrc ! audioconvert ! vorbisenc ! oggmux ! filesink location=input.ogg
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```
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### Video
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**Note:** For audio/video playback it's best to use the `playbin3` or
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`uridecodebin3` elements, these are just example pipelines.
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Display only the video portion of an MPEG-2 video file, outputting to an X
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display window:
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```
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gst-launch-1.0 filesrc location=JB_FF9_TheGravityOfLove.mpg ! mpegdemux ! mpegvideoparse ! mpeg2dec ! videoconvert ! xvimagesink
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```
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Display the video portion of a .vob file (used on DVDs), outputting to an SDL
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window:
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```
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gst-launch-1.0 filesrc location=flflfj.vob ! dvddemux ! mpegvideoparse ! mpeg2dec ! videoconvert ! sdlvideosink
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```
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Play both video and audio portions of an MPEG movie:
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```
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gst-launch-1.0 filesrc location=movie.mpg ! dvddemux name=demuxer \
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\
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demuxer. ! queue ! mpegvideoparse ! mpeg2dec ! videoconvert ! sdlvideosink \
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demuxer. ! queue ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! pulsesink
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```
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Play an AVI movie with an external text subtitle stream:
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This example shows how to refer to specific pads by name if an
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element (here: textoverlay) has multiple sink or source pads:
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```
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gst-launch-1.0 textoverlay name=overlay ! videoconvert ! videoscale ! autovideosink \
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filesrc location=movie.avi ! decodebin3 ! videoconvert ! overlay.video_sink \
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filesrc location=movie.srt ! subparse ! overlay.text_sink
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```
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Play an AVI movie with an external text subtitle stream using playbin:
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```
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gst-launch-1.0 playbin3 uri=<file:///path/to/movie.avi> suburi=<file:///path/to/movie.srt>
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```
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### Network streaming
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Stream video using RTP and network elements
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This command would be run on the transmitter:
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```
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gst-launch-1.0 v4l2src ! queue ! videoconvert ! x264enc tune=zerolatency key-int-max=15 ! video/x-h264,profile=main ! rtph264pay pt=96 config-interval=-1 ! udpsink host=192.168.1.1 port=5000
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```
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Use this command on the receiver:
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```
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gst-launch-1.0 udpsrc port=5000 ! application/x-rtp,clock-rate=90000,payload=96 ! rtpjitterbuffer ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! xvimagesink
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```
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### Diagnostic
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Generate a null stream and ignore it (and print out details):
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```
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gst-launch-1.0 -v fakesrc num-buffers=16 ! fakesink silent=false
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```
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Generate a pure sine tone to test the audio output:
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```
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gst-launch-1.0 audiotestsrc ! audioconvert ! audioresample ! osssink
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```
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Generate a familiar test pattern to test the video output:
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```
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gst-launch-1.0 videotestsrc ! ximagesink
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```
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```
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gst-launch-1.0 videotestsrc ! xvimagesink
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```
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### Automatic linking
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You can use the "decodebin3" element to automatically select the right
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elements to get a working pipeline.
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Play any supported audio format:
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```
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gst-launch-1.0 filesrc location=musicfile ! decodebin3 ! audioconvert ! audioresample ! pulsesink
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```
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Play any supported video format with video and audio output. Threads are used
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automatically:
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```
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gst-launch-1.0 filesrc location=videofile ! decodebin name=decoder decoder. ! queue ! audioconvert ! audioresample ! pulsesink decoder. ! videoconvert ! xvimagesink
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```
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You can also support different inputs by using an URI and uridecodebin3, e.g.:
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```
|
||
gst-launch-1.0 uridecodebin3 uri=file:///path/to/video.mp4 name=decoder decoder. ! queue ! audioconvert ! audioresample ! pulsesink decoder. ! videoconvert ! xvimagesink
|
||
```
|
||
|
||
```
|
||
gst-launch-1.0 uridecodebin3 uri=https://gstreamer.freedesktop.org/data/media/sintel_trailer-480p.webm name=decoder decoder. ! queue ! audioconvert ! audioresample ! pulsesink decoder. ! videoconvert ! xvimagesink
|
||
```
|
||
|
||
To make the above even easier, you can use the playbin element:
|
||
|
||
```
|
||
gst-launch-1.0 playbin3 uri=file:///home/joe/foo.avi
|
||
```
|
||
|
||
```
|
||
gst-launch-1.0 playbin3 uri=https://gstreamer.freedesktop.org/data/media/sintel_trailer-480p.webm
|
||
```
|
||
|
||
### 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
|
||
```
|
||
|
||
or
|
||
|
||
```
|
||
gst-launch-1.0 v4l2src ! image/jpeg ! queue ! decodebin3 ! videoconvert ! autovideosink
|
||
```
|
||
|
||
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`). 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. 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.
|
||
|
||
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 or use the pipeline_snapshot
|
||
tracer from the GStreamer Rust plugins.
|
||
|
||
`GST_REGISTRY`: Path of the plugin registry file. The default is
|
||
`~/.cache/gstreamer-1.0/registry-CPU.xml` where CPU is the machine/cpu type
|
||
GStreamer was compiled for, e.g. 'x86_64', 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, have been added or have been removed. This will make GStreamer
|
||
skip the initial check to determine 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 will be output
|
||
to the standard error output.
|
||
|
||
`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`: This is a 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 under
|
||
gdb (or let it core dump). Then get a stack trace in the usual way.
|
||
|
||
[information]: images/icons/emoticons/information.svg
|