mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-06-26 01:40:38 +00:00
added gst-launch grammar reference
Original commit message from CVS: added gst-launch grammar reference
This commit is contained in:
Andy Wingo
parent
a64e400a97
commit
b3d5bbd72c
|
|
@ -16,7 +16,7 @@
|
|||
<title><command>gst-launch</command></title>
|
||||
<para>
|
||||
This is a tool that will construct pipelines based on a command-line
|
||||
syntax. FIXME: need a more extensive grammar reference
|
||||
syntax.
|
||||
</para>
|
||||
<para>
|
||||
A simple commandline looks like:
|
||||
|
|
@ -79,6 +79,73 @@ main (int argc, char *argv[])
|
|||
Note how we can retrieve the filesrc element from the constructed bin using the
|
||||
element name.
|
||||
</para>
|
||||
<sect2>
|
||||
<title>Grammar Reference</title>
|
||||
<para>
|
||||
The <command>gst-launch</command> syntax is processed by a flex/bison parser. This section
|
||||
is intended to provide a full specification of the grammar; any deviations from this
|
||||
specification is considered a bug.
|
||||
</para>
|
||||
<sect3>
|
||||
<title>Elements</title>
|
||||
<screen>
|
||||
... mad ...
|
||||
</screen>
|
||||
<para>
|
||||
A bare identifier (a string beginning with a letter and containing only letters,
|
||||
numbers, dashes, underscores, percent signs, or colons) will create an element from a
|
||||
given elementfactory. In this example, an instance of the "mad" mp3 decoding plugin will
|
||||
be created.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Connections</title>
|
||||
<screen>
|
||||
... !sink ...
|
||||
</screen>
|
||||
<para>
|
||||
An exclamation point, optionally having a qualified pad name (an the name of the pad,
|
||||
optionally preceded by the name of the element) on both sides, will connect two pads. If
|
||||
the source pad is not specified, a source pad from the immediately preceding element
|
||||
will be automatically chosen. If the sink pad is not specified, a sink pad from the next
|
||||
element to be constructed will be chosen. An attempt will be made to find compatible
|
||||
pads. Pad names may be preceded by an element name, as in
|
||||
<computeroutput>my_element_name.sink_pad</computeroutput>.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Properties</title>
|
||||
<screen>
|
||||
... location="http://gstreamer.net" ...
|
||||
</screen>
|
||||
<para>
|
||||
The name of a property, optionally qualified with an element name, and a value,
|
||||
separated by an equals sign, will set a property on an element. If the element is not
|
||||
specified, the previous element is assumed. Strings can optionally be enclosed in
|
||||
quotation marks. Characters in strings may be escaped with the backtick
|
||||
(<literal>\</literal>). If the right-hand side is all digits, it is considered to be an
|
||||
integer. If it is all digits and a decimal point, it is a double. If it is "true",
|
||||
"false", "TRUE", or "FALSE" it is considered to be boolean. Otherwise, it is parsed as a
|
||||
string. The type of the property is determined later on in the parsing, and the value is
|
||||
converted to the target type. This conversion is not guaranteed to work, it relies on
|
||||
the g_value_convert routines. No error message will be displayed on an invalid
|
||||
conversion, due to limitations in the value convert API.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Bins, Threads, and Pipelines</title>
|
||||
<screen>
|
||||
( ... )
|
||||
</screen>
|
||||
<para>
|
||||
A pipeline description between parentheses is placed into a bin. The open paren may be
|
||||
preceded by a type name, as in <computeroutput>jackbin.( ... )</computeroutput> to make
|
||||
a bin of a specified type. Square brackets make pipelines, and curly braces make
|
||||
threads. The default toplevel bin type is a pipeline, although putting the whole
|
||||
description within parentheses or braces can override this default.
|
||||
</para>
|
||||
</sect3>
|
||||
</sect2>
|
||||
</sect1>
|
||||
|
||||
<sect1>
|
||||
|
|
|
|||
|
|
@ -16,7 +16,7 @@
|
|||
<title><command>gst-launch</command></title>
|
||||
<para>
|
||||
This is a tool that will construct pipelines based on a command-line
|
||||
syntax. FIXME: need a more extensive grammar reference
|
||||
syntax.
|
||||
</para>
|
||||
<para>
|
||||
A simple commandline looks like:
|
||||
|
|
@ -79,6 +79,73 @@ main (int argc, char *argv[])
|
|||
Note how we can retrieve the filesrc element from the constructed bin using the
|
||||
element name.
|
||||
</para>
|
||||
<sect2>
|
||||
<title>Grammar Reference</title>
|
||||
<para>
|
||||
The <command>gst-launch</command> syntax is processed by a flex/bison parser. This section
|
||||
is intended to provide a full specification of the grammar; any deviations from this
|
||||
specification is considered a bug.
|
||||
</para>
|
||||
<sect3>
|
||||
<title>Elements</title>
|
||||
<screen>
|
||||
... mad ...
|
||||
</screen>
|
||||
<para>
|
||||
A bare identifier (a string beginning with a letter and containing only letters,
|
||||
numbers, dashes, underscores, percent signs, or colons) will create an element from a
|
||||
given elementfactory. In this example, an instance of the "mad" mp3 decoding plugin will
|
||||
be created.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Connections</title>
|
||||
<screen>
|
||||
... !sink ...
|
||||
</screen>
|
||||
<para>
|
||||
An exclamation point, optionally having a qualified pad name (an the name of the pad,
|
||||
optionally preceded by the name of the element) on both sides, will connect two pads. If
|
||||
the source pad is not specified, a source pad from the immediately preceding element
|
||||
will be automatically chosen. If the sink pad is not specified, a sink pad from the next
|
||||
element to be constructed will be chosen. An attempt will be made to find compatible
|
||||
pads. Pad names may be preceded by an element name, as in
|
||||
<computeroutput>my_element_name.sink_pad</computeroutput>.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Properties</title>
|
||||
<screen>
|
||||
... location="http://gstreamer.net" ...
|
||||
</screen>
|
||||
<para>
|
||||
The name of a property, optionally qualified with an element name, and a value,
|
||||
separated by an equals sign, will set a property on an element. If the element is not
|
||||
specified, the previous element is assumed. Strings can optionally be enclosed in
|
||||
quotation marks. Characters in strings may be escaped with the backtick
|
||||
(<literal>\</literal>). If the right-hand side is all digits, it is considered to be an
|
||||
integer. If it is all digits and a decimal point, it is a double. If it is "true",
|
||||
"false", "TRUE", or "FALSE" it is considered to be boolean. Otherwise, it is parsed as a
|
||||
string. The type of the property is determined later on in the parsing, and the value is
|
||||
converted to the target type. This conversion is not guaranteed to work, it relies on
|
||||
the g_value_convert routines. No error message will be displayed on an invalid
|
||||
conversion, due to limitations in the value convert API.
|
||||
</para>
|
||||
</sect3>
|
||||
<sect3>
|
||||
<title>Bins, Threads, and Pipelines</title>
|
||||
<screen>
|
||||
( ... )
|
||||
</screen>
|
||||
<para>
|
||||
A pipeline description between parentheses is placed into a bin. The open paren may be
|
||||
preceded by a type name, as in <computeroutput>jackbin.( ... )</computeroutput> to make
|
||||
a bin of a specified type. Square brackets make pipelines, and curly braces make
|
||||
threads. The default toplevel bin type is a pipeline, although putting the whole
|
||||
description within parentheses or braces can override this default.
|
||||
</para>
|
||||
</sect3>
|
||||
</sect2>
|
||||
</sect1>
|
||||
|
||||
<sect1>
|
||||
|
|
|
|||
|
|
@ -56,8 +56,6 @@
|
|||
</para>
|
||||
<informaltable pgwide="1" frame="none" role="enum">
|
||||
<tgroup cols="2">
|
||||
<colspec colwidth="2*" />
|
||||
<colspec colwidth="8*" />
|
||||
<tbody>
|
||||
<row>
|
||||
<entry><literal>GST_STATE_NULL</literal></entry>
|
||||
|
|
|
|||
Loading…
Reference in a new issue