doc: Consistently use 'filtergraph'

We used to use 'filtergraph' or 'filter graph' randomly.

'filtergraph' was chosen due to having 57 occurrences in
the documentation, whereas 'filter graph' had only 19.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

doc/faq.texi

@@ -399,7 +399,7 @@ why the converting filter was needed at that place.
 Just before the output is a likely place, as @option{-f lavfi} currently
 only support packed S16.
 
-Then insert the correct @code{aconvert} explicitly in the filter graph,
+Then insert the correct @code{aconvert} explicitly in the filtergraph,
 specifying the exact format.
 
 @example

doc/ffmpeg.texi

@@ -346,19 +346,19 @@ Use fixed quality scale (VBR). The meaning of @var{q} is
 codec-dependent.
 
 @anchor{filter_option}
-@item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
-Create the filter graph specified by @var{filter_graph} and use it to
+@item -filter[:@var{stream_specifier}] @var{filtergraph} (@emph{output,per-stream})
+Create the filtergraph specified by @var{filtergraph} and use it to
 filter the stream.
 
-@var{filter_graph} is a description of the filter graph to apply to
+@var{filtergraph} is a description of the filtergraph to apply to
 the stream, and must have a single input and a single output of the
-same type of the stream. In the filter graph, the input is associated
+same type of the stream. In the filtergraph, the input is associated
 to the label @code{in}, and the output to the label @code{out}. See
 the ffmpeg-filters manual for more information about the filtergraph
 syntax.
 
 See the @ref{filter_complex_option,,-filter_complex option} if you
-want to create filter graphs with multiple inputs and/or outputs.
+want to create filtergraphs with multiple inputs and/or outputs.
 
 @item -filter_script[:@var{stream_specifier}] @var{filename} (@emph{output,per-stream})
 This option is similar to @option{-filter}, the only difference is that its
@@ -496,8 +496,8 @@ stream
 @item -vlang @var{code}
 Set the ISO 639 language code (3 letters) of the current video stream.
 
-@item -vf @var{filter_graph} (@emph{output})
-Create the filter graph specified by @var{filter_graph} and use it to
+@item -vf @var{filtergraph} (@emph{output})
+Create the filtergraph specified by @var{filtergraph} and use it to
 filter the stream.
 
 This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
@@ -513,7 +513,7 @@ If the selected pixel format can not be selected, ffmpeg will print a
 warning and select the best pixel format supported by the encoder.
 If @var{pix_fmt} is prefixed by a @code{+}, ffmpeg will exit with an error
 if the requested pixel format can not be selected, and automatic conversions
-inside filter graphs are disabled.
+inside filtergraphs are disabled.
 If @var{pix_fmt} is a single @code{+}, ffmpeg selects the same pixel format
 as the input (or graph output) and automatic conversions are disabled.
 
@@ -637,8 +637,8 @@ Set the audio codec. This is an alias for @code{-codec:a}.
 Set the audio sample format. Use @code{-sample_fmts} to get a list
 of supported sample formats.
 
-@item -af @var{filter_graph} (@emph{output})
-Create the filter graph specified by @var{filter_graph} and use it to
+@item -af @var{filtergraph} (@emph{output})
+Create the filtergraph specified by @var{filtergraph} and use it to
 filter the stream.
 
 This is an alias for @code{-filter:a}, see the @ref{filter_option,,-filter option}.
@@ -1005,10 +1005,10 @@ ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
 
 @anchor{filter_complex_option}
 @item -filter_complex @var{filtergraph} (@emph{global})
-Define a complex filter graph, i.e. one with arbitrary number of inputs and/or
+Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
 outputs. For simple graphs -- those with one input and one output of the same
 type -- see the @option{-filter} options. @var{filtergraph} is a description of
-the filter graph, as described in the ``Filtergraph syntax'' section of the
+the filtergraph, as described in the ``Filtergraph syntax'' section of the
 ffmpeg-filters manual.
 
 Input link labels must refer to input streams using the
@@ -1052,7 +1052,7 @@ ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
 @end example
 
 @item -lavfi @var{filtergraph} (@emph{global})
-Define a complex filter graph, i.e. one with arbitrary number of inputs and/or
+Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
 outputs. Equivalent to @option{-filter_complex}.
 
 @item -filter_complex_script @var{filename} (@emph{global})

doc/ffplay.texi

@@ -73,19 +73,19 @@ Default value is "video", if video is not present or cannot be played
 You can interactively cycle through the available show modes by
 pressing the key @key{w}.
 
-@item -vf @var{filter_graph}
-Create the filter graph specified by @var{filter_graph} and use it to
+@item -vf @var{filtergraph}
+Create the filtergraph specified by @var{filtergraph} and use it to
 filter the video stream.
 
-@var{filter_graph} is a description of the filter graph to apply to
+@var{filtergraph} is a description of the filtergraph to apply to
 the stream, and must have a single video input and a single video
-output. In the filter graph, the input is associated to the label
+output. In the filtergraph, the input is associated to the label
 @code{in}, and the output to the label @code{out}. See the
 ffmpeg-filters manual for more information about the filtergraph
 syntax.
 
-@item -af @var{filter_graph}
-@var{filter_graph} is a description of the filter graph to apply to
+@item -af @var{filtergraph}
+@var{filtergraph} is a description of the filtergraph to apply to
 the input audio.
 Use the option "-filters" to show all the available filters (including
 sources and sinks).

doc/filters.texi

@@ -6,7 +6,7 @@ Filtering in FFmpeg is enabled through the libavfilter library.
 In libavfilter, it is possible for filters to have multiple inputs and
 multiple outputs.
 To illustrate the sorts of things that are possible, we can
-use a complex filter graph. For example, the following one:
+use a complex filtergraph. For example, the following one:
 
 @example
 input --> split ---------------------> overlay --> output
@@ -49,7 +49,7 @@ output.
 @c man begin GRAPH2DOT
 
 The @file{graph2dot} program included in the FFmpeg @file{tools}
-directory can be used to parse a filter graph description and issue a
+directory can be used to parse a filtergraph description and issue a
 corresponding textual representation in the dot language.
 
 Invoke the command:
@@ -61,7 +61,7 @@ to see how to use @file{graph2dot}.
 
 You can then pass the dot description to the @file{dot} program (from
 the graphviz suite of programs) and obtain a graphical representation
-of the filter graph.
+of the filtergraph.
 
 For example the sequence of commands:
 @example
@@ -2865,7 +2865,7 @@ they should be escaped.
 
 Note that they probably must also be escaped as the value for the
 @option{text} option in the filter argument string and as the filter
-argument in the filter graph description, and possibly also for the shell,
+argument in the filtergraph description, and possibly also for the shell,
 that makes up to four levels of escaping; using a text file avoids these
 problems.