Merge commit 'e6bc38fd49c94726b45d5d5cc2b756ad8ec49ee0'

[ffmpeg] / doc / ffmpeg.texi

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index d0fe327c15545366cdfbc408b978ffcf3c896df0..5aa45629d4795e71fe3a85f1b20898a30047728c 100644 (file)
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -334,13 +334,21 @@ Stop writing to the stream after @var{framecount} frames.
 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
+filter the stream.
+
 @var{filter_graph} is a description of the filter graph to apply to
-the stream. Use @code{-filters} to show all the available filters
-(including also sources and sinks).
+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
+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.
 
-See also the @option{-filter_complex} option if you want to create filter graphs
-with multiple inputs and/or outputs.
 @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
 Specify the preset for matching stream(s).
 
@@ -487,11 +495,10 @@ stream
 Set the ISO 639 language code (3 letters) of the current video stream.
 
 @item -vf @var{filter_graph} (@emph{output})
-@var{filter_graph} is a description of the filter graph to apply to
-the input video.
-Use the option "-filters" to show all the available filters (including
-also sources and sinks).  This is an alias for @code{-filter:v}.
+Create the filter graph specified by @var{filter_graph} and use it to
+filter the stream.
 
+This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
 @end table
 
 @section Advanced Video Options
@@ -548,9 +555,17 @@ Deprecated see -bsf
 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
 Force key frames at the specified timestamps, more precisely at the first
 frames after each specified time.
+If one of the times is "@code{chapters}[@var{delta}]", it is expanded into
+the time of the beginning of all chapters in the file, shifted by
+@var{delta}, expressed as a time in seconds.
 This option can be useful to ensure that a seek point is present at a
 chapter mark or any other designated place in the output file.
-The timestamps must be specified in ascending order.
+
+For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
+before the beginning of every chapter:
+@example
+-force_key_frames 0:05:00,chapters-0.1
+@end example
 
 @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
 When doing stream copy, copy also non-key frames found at the
@@ -581,11 +596,12 @@ Set the audio codec. This is an alias for @code{-codec:a}.
 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
 Set the audio sample format. Use @code{-sample_fmts} to get a list
 of supported sample formats.
+
 @item -af @var{filter_graph} (@emph{output})
-@var{filter_graph} is a description of the filter graph to apply to
-the input audio.
-Use the option "-filters" to show all the available filters (including
-also sources and sinks).  This is an alias for @code{-filter:a}.
+Create the filter graph specified by @var{filter_graph} and use it to
+filter the stream.
+
+This is an alias for @code{-filter:a}, see the @ref{filter_option,,-filter option}.
 @end table
 
 @section Advanced Audio options:
@@ -928,6 +944,7 @@ Specify Timecode for writing. @var{SEP} is ':' for non drop timecode and ';'
 ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
 @end example
 
+@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
 outputs. For simple graphs -- those with one input and one output of the same
@@ -972,7 +989,7 @@ ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
 
 To generate 5 seconds of pure red video using lavfi @code{color} source:
 @example
-ffmpeg -filter_complex 'color=red' -t 5 out.mkv
+ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
 @end example
 @end table