[FFmpeg-devel] [PATCH 2/3] doc/filters: Cosmetics

Timothy Gu timothygu99 at gmail.com
Sun Sep 22 00:39:36 CEST 2013


Signed-off-by: Timothy Gu <timothygu99 at gmail.com>
---
Most of them are just nits, line wrapping, and stuff like that. It's quite
boring.
---
 doc/filters.texi | 357 +++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 227 insertions(+), 130 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 4de09ca..ea20b46 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -22,7 +22,10 @@ back with the other stream by overlaying it on top. You can use the
 following command to achieve this:
 
 @example
-ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
+ffmpeg -i INPUT -vf \
+"split [main][tmp]; \
+ [tmp] crop=iw:ih/2:0:0, vflip [flip]; \
+ [main][flip] overlay=0:H/2" OUTPUT
 @end example
 
 The result will be that in output the top half of the video is mirrored
@@ -61,6 +64,7 @@ directory can be used to parse a filtergraph description and issue a
 corresponding textual representation in the dot language.
 
 Invoke the command:
+
 @example
 graph2dot -h
 @end example
@@ -72,6 +76,7 @@ the graphviz suite of programs) and obtain a graphical representation
 of the filtergraph.
 
 For example the sequence of commands:
+
 @example
 echo @var{GRAPH_DESCRIPTION} | \
 tools/graph2dot -o graph.tmp && \
@@ -81,17 +86,22 @@ display graph.png
 
 can be used to create and display an image representing the graph
 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
-a complete self-contained graph, with its inputs and outputs explicitly defined.
-For example if your command line is of the form:
+a complete self-contained graph, with its inputs and outputs explicitly
+defined. For example if your command line is of the form:
+
 @example
 ffmpeg -i infile -vf scale=640:360 outfile
 @end example
-your @var{GRAPH_DESCRIPTION} string will need to be of the form:
+
+Your @var{GRAPH_DESCRIPTION} string will need to be of the form:
+
 @example
 nullsrc,scale=640:360,nullsink
 @end example
-you may also need to set the @var{nullsrc} parameters and add a @var{format}
-filter in order to simulate a specific input file.
+
+You may also need to set some parameters for @var{nullsrc} and add a
+ at var{format} filter in order to simulate a specific input file. See
+documentation for both of the filters below.
 
 @c man end GRAPH2DOT
 
@@ -117,8 +127,8 @@ output pads is called a "sink".
 A filtergraph can be represented using a textual representation, which is
 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
- at code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
- at file{libavfilter/avfilter.h}.
+ at code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined
+in @file{libavfilter/avfilter.h}.
 
 A filterchain consists of a sequence of connected filters, each one
 connected to the previous one in the sequence. A filterchain is
@@ -184,10 +194,13 @@ created.
 
 If an output pad is not labelled, it is linked by default to the first
 unlabelled input pad of the next filter in the filterchain.
+
 For example in the filterchain:
+
 @example
 nullsrc, split[L1], [L2]overlay, nullsink
 @end example
+
 the split filter instance has two output pads, and the overlay filter
 instance two input pads. The first output pad of split is labelled
 "L1", the first input pad of overlay is labelled "L2", and the second
@@ -198,7 +211,7 @@ In a complete filterchain all the unlabelled filter input and output
 pads must be connected. A filtergraph is considered valid if all the
 filter input and output pads of all the filterchains are connected.
 
-Libavfilter will automatically insert scale filters where format
+libavfilter will automatically insert scale filters where format
 conversion is required. It is possible to specify swscale flags
 for those automatically inserted scalers by prepending
 @code{sws_flags=@var{flags};}
@@ -245,7 +258,8 @@ escaping rules of the adopted shell. For example, assuming that
 @code{\} is special and needs to be escaped with another @code{\}, the
 previous string will finally result in:
 @example
--vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
+-vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or \
+     more\\, special characters"
 @end example
 
 Sometimes, it might be more convenient to employ quoting in place of
@@ -260,6 +274,7 @@ text='Caesar: tu quoque, Brute, fili mi'
 @end example
 
 And finally inserted in a filtergraph like:
+
 @example
 drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'
 @end example
@@ -382,9 +397,9 @@ Apply echoing to the input audio.
 Echoes are reflected sound and can occur naturally amongst mountains
 (and sometimes large buildings) when talking or shouting; digital echo
 effects emulate this behaviour and are often used to help fill out the
-sound of a single instrument or vocal. The time difference between the
-original signal and the reflection is the @code{delay}, and the
-loudness of the reflected signal is the @code{decay}.
+sound of a single instrument or vocal. The time differences between the
+original signal and the reflection are the @code{delays}, and the
+loudnesses of the reflected signal are the @code{decays}.
 Multiple echoes can have different delays and decays.
 
 A description of the accepted parameters follows.
@@ -397,14 +412,14 @@ Set input gain of reflected signal. Default is @code{0.6}.
 Set output gain of reflected signal. Default is @code{0.3}.
 
 @item delays
-Set list of time intervals in milliseconds between original signal and reflections
-separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
-Default is @code{1000}.
+Set list of time intervals in milliseconds between original signal and
+reflections separated by '|'. Allowed range for each @code{delays} is
+ at code{(0 - 90000.0]}. Default is @samp{1000}.
 
 @item decays
 Set list of loudnesses of reflected signals separated by '|'.
-Allowed range for each @code{decay} is @code{(0 - 1.0]}.
-Default is @code{0.5}.
+Allowed range for each @option{decays} is @code{(0 - 1.0]}.
+Default is @samp{0.5}.
 @end table
 
 @subsection Examples
@@ -458,26 +473,34 @@ the output audio will be silence. Default is 44100.
 
 @item start_time, st
 Specify time for starting to apply the fade effect. Default is 0.
+
 The accepted syntax is:
+
 @example
 [-]HH[:MM[:SS[.m...]]]
 [-]S+[.m...]
 @end example
-See also the function @code{av_parse_time()}.
-If set this option is used instead of @var{start_sample} one.
+
+Also see the function @code{av_parse_time()}.
+
+If set, this option is used instead of @var{start_sample} one.
 
 @item duration, d
 Specify the duration for which the fade effect has to last. Default is 0.
 The accepted syntax is:
+
 @example
 [-]HH[:MM[:SS[.m...]]]
 [-]S+[.m...]
 @end example
-See also the function @code{av_parse_time()}.
+
+Also see the function @code{av_parse_time()}.
+
 At the end of the fade-in effect the output audio will have the same
 volume as the input audio, at the end of the fade-out transition
 the output audio will be silence.
-If set this option is used instead of @var{nb_samples} one.
+
+If set, this option is used instead of @var{nb_samples} one.
 
 @item curve
 Set curve for fade transition.
@@ -545,7 +568,9 @@ A '|'-separated list of requested channel layouts.
 
 If a parameter is omitted, all values are allowed.
 
-For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
+For example to force the output to either unsigned 8-bit or signed 16-bit
+stereo:
+
 @example
 aformat=sample_fmts=u8|s16:channel_layouts=stereo
 @end example
@@ -627,7 +652,8 @@ amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
 @item
 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
 @example
-ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
+ffmpeg -i input.mkv -filter_complex \
+"[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
 @end example
 @end itemize
 
@@ -636,9 +662,12 @@ ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=input
 Mixes multiple audio inputs into a single output.
 
 For example
+
 @example
-ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
+ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 \
+-filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
 @end example
+
 will mix 3 input audio streams to a single output with the same duration as the
 first input and a dropout transition time of 3 seconds.
 
@@ -682,7 +711,8 @@ Pad the end of a audio stream with silence, this can be used together with
 Add a phasing effect to the input audio.
 
 A phaser filter creates series of peaks and troughs in the frequency spectrum.
-The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
+The position of the peaks and troughs are modulated so that they vary over
+time, creating a sweeping effect.
 
 A description of the accepted parameters follows.
 
@@ -838,7 +868,8 @@ Display time domain statistical information about the audio channels.
 Statistics are calculated and displayed for each audio channel and,
 where applicable, an overall figure is also given.
 
-The filter accepts the following option:
+The filter accepts the following options:
+
 @table @option
 @item length
 Short window length in seconds, used for peak and trough RMS measurement.
@@ -847,7 +878,7 @@ Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
 
 A description of each shown parameter follows:
 
- at table @option
+ at table @var
 @item DC offset
 Mean amplitude displacement from zero.
 
@@ -869,8 +900,8 @@ Peak and trough values for RMS level measured over a short window.
 Standard ratio of peak to RMS level (note: not in dB).
 
 @item Flat factor
-Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
-(i.e. either @var{Min level} or @var{Max level}).
+Flatness (i.e. consecutive samples with the same value) of the signal at its
+peak levels (i.e. either @var{Min level} or @var{Max level}).
 
 @item Peak count
 Number of occasions (not the number of samples) that the signal attained either
@@ -907,10 +938,11 @@ that has a smaller timestamp.
 
 Stress-test @code{amerge} by randomly sending buffers on the wrong
 input, while avoiding too much of a desynchronization:
+
 @example
-amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
-[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
-[a2] [b2] amerge
+amovie=file.ogg[a]; amovie=file.mp3[b]; \
+[a][b]astreamsync=(2*random(1))-1+tanh(5*(t1-t2))[a2][b2]; \
+[a2][b2] amerge
 @end example
 
 @section asyncts
@@ -918,7 +950,8 @@ amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
 Synchronize audio data with timestamps by squeezing/stretching it and/or
 dropping samples/adding silence when needed.
 
-This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
+This filter is not built by default, please use @ref{aresample} to do
+squeezing/stretching.
 
 The filter accepts the following named parameters:
 @table @option
@@ -1009,11 +1042,11 @@ ffmpeg-utils manual.
 
 Note that the first two sets of the start/end options and the @option{duration}
 option look at the frame timestamp, while the _sample options simply count the
-samples that pass through the filter. So start/end_pts and start/end_sample will
-give different results when the timestamps are wrong, inexact or do not start at
-zero. Also note that this filter does not modify the timestamps. If you wish
-that the output timestamps start at zero, insert the asetpts filter after the
-atrim filter.
+samples that pass through the filter. So start/end_pts and start/end_sample
+will give different results when the timestamps are wrong, inexact or do not
+start at zero. Also note that this filter does not modify the timestamps. If
+you wish that the output timestamps start at zero, insert the asetpts filter
+after the atrim filter.
 
 If multiple start or end options are set, this filter tries to be greedy and
 keep all samples that match at least one of the specified constraints. To keep
@@ -1026,15 +1059,15 @@ just the end values to keep everything before the specified time.
 Examples:
 @itemize
 @item
-drop everything except the second minute of input
+Drop everything except the second minute of input
 @example
-ffmpeg -i INPUT -af atrim=60:120
+ffmpeg -i INPUT -af atrim=60:120 OUTPUT
 @end example
 
 @item
-keep only the first 1000 samples
+Keep only the first 1000 samples
 @example
-ffmpeg -i INPUT -af atrim=end_sample=1000
+ffmpeg -i INPUT -af atrim=end_sample=1000 OUTPUT
 @end example
 
 @end itemize
@@ -1167,13 +1200,16 @@ If no mapping is present, the filter will implicitly map input channels to
 output channels preserving index.
 
 For example, assuming a 5.1+downmix input MOV file
+
 @example
 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
 @end example
+
 will create an output WAV file tagged as stereo from the downmix channels of
 the input.
 
 To fix a 5.1 WAV improperly encoded in AAC's native channel order
+
 @example
 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
 @end example
@@ -1183,25 +1219,32 @@ ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
 Split each channel in input audio stream into a separate output stream.
 
 This filter accepts the following named parameters:
+
 @table @option
 @item channel_layout
 Channel layout of the input stream. Default is "stereo".
 @end table
 
 For example, assuming a stereo input MP3 file
+
 @example
 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
 @end example
+
 will create an output Matroska file with two audio streams, one containing only
 the left channel and the other the right channel.
 
 To split a 5.1 WAV file into per-channel files
+
 @example
-ffmpeg -i in.wav -filter_complex
-'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
--map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
-front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
-side_right.wav
+ffmpeg -i in.wav -filter_complex \
+'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]' \
+-map '[FL]'  front_left.wav \
+-map '[FR]'  front_right.wav \
+-map '[FC]'  front_center.wav \
+-map '[LFE]' lfe.wav \
+-map '[SL]'  side_left.wav \
+-map '[SR]'  side_right.wav
 @end example
 
 @section compand
@@ -1310,6 +1353,7 @@ Set the filter's central frequency in Hz.
 
 @item width_type
 Set method to specify band-width of filter.
+
 @table @option
 @item h
 Hz
@@ -1360,7 +1404,8 @@ slope
 @item width, w
 Specify the band-width of a filter in width_type units.
 Applies only to double-pole filter.
-The default is 0.707q and gives a Butterworth response.
+
+The default is @samp{0.707q} and gives a Butterworth response.
 @end table
 
 @section join
@@ -1368,8 +1413,8 @@ The default is 0.707q and gives a Butterworth response.
 Join multiple input streams into one multi-channel stream.
 
 The filter accepts the following named parameters:
- at table @option
 
+ at table @option
 @item inputs
 Number of input streams. Defaults to 2.
 
@@ -1379,10 +1424,10 @@ Desired output channel layout. Defaults to stereo.
 @item map
 Map channels from inputs to output. The argument is a '|'-separated list of
 mappings, each in the @code{@var{input_idx}. at var{in_channel}- at var{out_channel}}
-form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
-can be either the name of the input channel (e.g. FL for front left) or its
-index in the specified input stream. @var{out_channel} is the name of the output
-channel.
+form. @var{input_idx} is the 0-based index of the input stream.
+ at var{in_channel} can be either the name of the input channel (e.g. FL for front
+left) or its index in the specified input stream. @var{out_channel} is the name
+of the output channel.
 @end table
 
 The filter will attempt to guess the mappings when those are not specified
@@ -1395,10 +1440,11 @@ ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
 @end example
 
 To build a 5.1 output from 6 single-channel streams:
+
 @example
-ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
-'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
-out
+ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex \
+'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE' \
+OUT
 @end example
 
 @section lowpass
@@ -1955,7 +2001,7 @@ flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':
 @item
 Input text to ffmpeg:
 @example
-ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
+ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of':voice=slt
 @end example
 
 @item
@@ -1967,7 +2013,7 @@ ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
 @end itemize
 
 For more information about libflite, check:
- at url{http://www.speech.cs.cmu.edu/flite/}
+ at url{http://www.speech.cs.cmu.edu/flite/}.
 
 @section sine
 
@@ -2230,15 +2276,17 @@ Available values for component modes are:
 @item c3_opacity
 @item all_opacity
 Set blend opacity for specific pixel component or all pixel components in case
-of @var{all_opacity}. Only used in combination with pixel component blend modes.
+of @var{all_opacity}. Only used in combination with pixel component blend
+modes.
 
 @item c0_expr
 @item c1_expr
 @item c2_expr
 @item c3_expr
 @item all_expr
-Set blend expression for specific pixel component or all pixel components in case
-of @var{all_expr}. Note that related mode options will be ignored if those are set.
+Set blend expression for specific pixel component or all pixel components
+incase of @var{all_expr}. Note that related mode options will be ignored if
+those are set.
 
 The expressions can use the following variables:
 
@@ -2268,15 +2316,18 @@ Time of the current frame, expressed in seconds.
 Value of pixel component at current location for first video frame (top layer).
 
 @item BOTTOM, B
-Value of pixel component at current location for second video frame (bottom layer).
+Value of pixel component at current location for second video frame (bottom
+layer).
 @end table
 
 @item shortest
 Force termination when the shortest input terminates. Default is @code{0}.
 @item repeatlast
 Continue applying the last bottom frame after the end of the stream. A value of
- at code{0} disable the filter after the last frame of the bottom layer is reached.
-Default is @code{1}.
+ at code{0} disable the filter after the last frame of the bottom layer is
+reached.
+
+Default is @samp{1}.
 @end table
 
 @subsection Examples
@@ -2379,18 +2430,19 @@ boxblur=2:1:cr=0:ar=0
 @item
 Set luma and chroma radius to a fraction of the video dimension:
 @example
-boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
+boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:\
+chroma_power=1
 @end example
 @end itemize
 
 @section colorbalance
 Modify intensity of primary colors (red, green and blue) of input frames.
 
-The filter allows an input frame to be adjusted in the shadows, midtones or highlights
-regions for the red-cyan, green-magenta or blue-yellow balance.
+The filter allows an input frame to be adjusted in the shadows, midtones or
+highlights regions for the red-cyan, green-magenta or blue-yellow balance.
 
-A positive adjustment value shifts the balance towards the primary color, a negative
-value towards the complementary color.
+A positive adjustment value shifts the balance towards the primary color, a
+negative value towards the complementary color.
 
 The filter accepts the following options:
 
@@ -2441,29 +2493,40 @@ The filter accepts the following options:
 @item rg
 @item rb
 @item ra
-Adjust contribution of input red, green, blue and alpha channels for output red channel.
-Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
+Adjust contribution of input red, green, blue and alpha channels for output red
+channel.
+
+Default is @samp{1} for @option{rr}, and @samp{0} for @option{rg},
+ at option{rb} and @option{ra}.
 
 @item gr
 @item gg
 @item gb
 @item ga
-Adjust contribution of input red, green, blue and alpha channels for output green channel.
-Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
+Adjust contribution of input red, green, blue and alpha channels for output
+green channel.
+
+Default is @samp{1} for @option{gg}, and @samp{0} for @option{gr}, @option{gb},
+and @option{ga}.
 
 @item br
 @item bg
 @item bb
 @item ba
-Adjust contribution of input red, green, blue and alpha channels for output blue channel.
-Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
+Adjust contribution of input red, green, blue and alpha channels for output
+blue channel.
+
+Default is @samp{1} for @option{bb}, and @samp{0} for @option{br}, @option{bg}
+and @option{ba}.
 
 @item ar
 @item ag
 @item ab
 @item aa
 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
-Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
+
+Default is @samp{1} for @option{aa}, and @samp{0} for @option{ar}, @option{ag}
+and @option{ab}.
 
 Allowed ranges for options are @code{[-2.0, 2.0]}.
 @end table
@@ -2762,7 +2825,9 @@ The filter accepts the following options:
 Select one of the available color presets. This option can be used in addition
 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
 options takes priority on the preset values.
+
 Available presets are:
+
 @table @samp
 @item none
 @item color_negative
@@ -2776,23 +2841,30 @@ Available presets are:
 @item strong_contrast
 @item vintage
 @end table
-Default is @code{none}.
+
+Default is @samp{none}.
+
 @item master, m
 Set the master key points. These points will define a second pass mapping. It
 is sometimes called a "luminance" or "value" mapping. It can be used with
 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
 post-processing LUT.
+
 @item red, r
 Set the key points for the red component.
+
 @item green, g
 Set the key points for the green component.
+
 @item blue, b
 Set the key points for the blue component.
+
 @item all
 Set the key points for all components (not including master).
 Can be used in addition to the other key points component
 options. In this case, the unset component(s) will fallback on this
 @option{all} setting.
+
 @item psfile
 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
 @end table
@@ -3022,6 +3094,7 @@ range 0-64 pixels. Default 16.
 @item edge
 Specify how to generate pixels to fill blanks at the edge of the
 frame. Available values are:
+
 @table @samp
 @item blank, 0
 Fill zeroes at blank locations
@@ -3032,6 +3105,7 @@ Extruded edge value at blank locations
 @item mirror, 3
 Mirrored edge at blank locations
 @end table
+
 Default value is @samp{mirror}.
 
 @item blocksize
@@ -3045,12 +3119,14 @@ pixels) will be considered. Range 1-255, default 125.
 
 @item search
 Specify the search strategy. Available values are:
+
 @table @samp
 @item exhaustive, 0
 Set exhaustive search
 @item less, 1
 Set less exhaustive search.
 @end table
+
 Default value is @samp{exhaustive}.
 
 @item filename
@@ -3072,31 +3148,34 @@ This filter accepts the following options:
 @table @option
 @item x
 @item y
-The expressions which specify the top left corner coordinates of the box. Default to 0.
+The expressions which specify the top left corner coordinates of the box.
+Default to 0.
 
 @item width, w
 @item height, h
-The expressions which specify the width and height of the box, if 0 they are interpreted as
-the input width and height. Default to 0.
+The expressions which specify the width and height of the box, if 0 they are
+interpreted as the input width and height. Default to 0.
 
 @item color, c
 Specify the color of the box to write, it can be the name of a color
 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
-value @code{invert} is used, the box edge color is the same as the
+value @samp{invert} is used, the box edge color is the same as the
 video with inverted luma.
 
 @item thickness, t
-The expression which sets the thickness of the box edge. Default value is @code{3}.
+The expression which sets the thickness of the box edge. Default value is
+ at samp{3}.
 
 See below for the list of accepted constants.
 @end table
 
-The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
-following constants:
+The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are
+expressions containing the following constants:
 
 @table @option
 @item dar
-The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
+The input display aspect ratio, it is the same as 
+ at code{(@var{w} / @var{h}) * @var{sar}}.
 
 @item hsub
 @item vsub
@@ -3121,8 +3200,9 @@ The width and height of the drawn box.
 @item t
 The thickness of the drawn box.
 
-These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
-each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
+These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t}
+expressions to refer to each other, so you may for example specify
+ at code{y=x/dar} or @code{h=w/dar}.
 
 @end table
 
@@ -3168,34 +3248,38 @@ This filter accepts the following options:
 @table @option
 @item x
 @item y
-The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
+The expressions which specify the coordinates of some point of grid
+intersection (meant to configure offset). Both default to 0.
 
 @item width, w
 @item height, h
-The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
-input width and height, respectively, minus @code{thickness}, so image gets
-framed. Default to 0.
+The expressions which specify the width and height of the grid cell, if 0 they
+are interpreted as the input width and height, respectively, minus
+ at option{thickness}, so image gets framed. Default to 0.
 
 @item color, c
 Specify the color of the grid, it can be the name of a color
 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
-value @code{invert} is used, the grid color is the same as the
+value @samp{invert} is used, the grid color is the same as the
 video with inverted luma.
+
 Note that you can append opacity value (in range of 0.0 - 1.0)
 to color name after @@ sign.
 
 @item thickness, t
-The expression which sets the thickness of the grid line. Default value is @code{1}.
+The expression which sets the thickness of the grid line. Default value is
+ at samp{1}.
 
 See below for the list of accepted constants.
 @end table
 
-The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
-following constants:
+The parameters for @option{x}, @option{y}, @option{w} and @option{h} and
+ at option{t} are expressions containing the following constants:
 
- at table @option
+ at table @var
 @item dar
-The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
+The input display aspect ratio, it is the same as
+ at code{(@var{w} / @var{h}) * @var{sar}}.
 
 @item hsub
 @item vsub
@@ -3211,7 +3295,8 @@ The input sample aspect ratio.
 
 @item x
 @item y
-The x and y coordinates of some point of grid intersection (meant to configure offset).
+The x and y coordinates of some point of grid intersection (meant to configure
+offset).
 
 @item w
 @item h
@@ -3220,8 +3305,9 @@ The width and height of the drawn cell.
 @item t
 The thickness of the drawn cell.
 
-These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
-each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
+These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t}
+expressions to refer to each other, so you may for example specify
+ at code{y=x/dar} or @code{h=w/dar}.
 
 @end table
 
@@ -3229,7 +3315,8 @@ each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
 
 @itemize
 @item
-Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
+Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an
+opacity of 50%:
 @example
 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
 @end example
@@ -3295,7 +3382,8 @@ Flags to be used for loading the fonts.
 
 The flags map the corresponding flags supported by libfreetype, and are
 a combination of the following values:
- at table @var
+
+ at table @samp
 @item default
 @item no_scale
 @item no_hinting
@@ -3313,7 +3401,7 @@ a combination of the following values:
 @item no_autohint
 @end table
 
-Default value is "render".
+Default value is @samp{render}.
 
 For more information consult the documentation for the FT_LOAD_*
 libfreetype flags.
@@ -3519,7 +3607,8 @@ Draw "Test Text" with font FreeSerif, using the default values for the
 optional parameters.
 
 @example
-drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
+drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:\
+          text='Test Text'"
 @end example
 
 @item
@@ -3529,8 +3618,9 @@ yellow with a red box around it. Both the text and the box have an
 opacity of 20%.
 
 @example
-drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
-          x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
+drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:\
+          text='Test Text': x=100: y=50: fontsize=24: fontcolor=yellow@@0.2:\
+          box=1: boxcolor=red@@0.2"
 @end example
 
 Note that the double quotes are not necessary if spaces are not used
@@ -3539,7 +3629,8 @@ within the parameter list.
 @item
 Show the text at the center of the video frame:
 @example
-drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
+drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':\
+          x=(w-text_w)/2:y=(h-text_h-line_h)/2"
 @end example
 
 @item
@@ -3551,7 +3642,8 @@ drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
 @end example
 
 @item
-Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
+Show the content of file @file{CREDITS} off the bottom of the frame and scroll
+up.
 @example
 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
 @end example
@@ -3560,13 +3652,15 @@ drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
 Draw a single green letter "g", at the center of the input video.
 The glyph baseline is placed at half screen height.
 @example
-drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
+drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:\
+          x=(w-max_glyph_w)/2:y=h/2-ascent"
 @end example
 
 @item
 Show text for 1 second every 3 seconds:
 @example
-drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
+drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:\
+          enable=lt(mod(t\,3)\,1):text='blink'"
 @end example
 
 @item
@@ -3605,14 +3699,15 @@ The high threshold selects the "strong" edge pixels, which are then
 connected through 8-connectivity with the "weak" edge pixels selected
 by the low threshold.
 
- at var{low} and @var{high} threshold values must be choosen in the range
-[0,1], and @var{low} should be lesser or equal to @var{high}.
+ at option{low} and @option{high} threshold values must be choosen in the range
+ at code{[0,1]}, and @option{low} should be lesser or equal to @option{high}.
 
-Default value for @var{low} is @code{20/255}, and default value for @var{high}
-is @code{50/255}.
+Default value for @option{low} is @samp{20/255}, and default value for
+ at option{high} is @samp{50/255}.
 @end table
 
-Example:
+ at subsection Examples
+
 @example
 edgedetect=low=0.1:high=0.4
 @end example
@@ -3640,8 +3735,8 @@ Available values for planes are:
 @end table
 
 Choosing planes not available in the input will result in an error.
-That means you cannot select @code{r}, @code{g}, @code{b} planes
-with @code{y}, @code{u}, @code{v} planes at same time.
+That means you cannot select @samp{r}, @samp{g}, @samp{b} planes
+with @samp{y}, @samp{u}, @samp{v} planes at same time.
 @end table
 
 @subsection Examples
@@ -3651,7 +3746,8 @@ with @code{y}, @code{u}, @code{v} planes at same time.
 Extract luma, u and v color channel component from input video frame
 into 3 grayscale outputs:
 @example
-ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
+ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' \
+-map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
 @end example
 @end itemize
 
@@ -3673,24 +3769,25 @@ effect. Default is 0.
 
 @item nb_frames, n
 The number of frames for which the fade effect has to last. At the end of the
-fade-in effect the output video will have the same intensity as the input video,
-at the end of the fade-out transition the output video will be completely black.
-Default is 25.
+fade-in effect the output video will have the same intensity as the input
+video, at the end of the fade-out transition the output video will be
+completely black. Default is 25.
 
 @item alpha
-If set to 1, fade only alpha channel, if one exists on the input.
-Default value is 0.
+If set to 1, fade only alpha channel, if one exists on the input. Default value
+is 0.
 
 @item start_time, st
 Specify the timestamp (in seconds) of the frame to start to apply the fade
-effect. If both start_frame and start_time are specified, the fade will start at
-whichever comes last.  Default is 0.
+effect. If both start_frame and start_time are specified, the fade will start
+at whichever comes last. Default is 0.
 
 @item duration, d
 The number of seconds for which the fade effect has to last. At the end of the
-fade-in effect the output video will have the same intensity as the input video,
-at the end of the fade-out transition the output video will be completely black.
-If both duration and nb_frames are specified, duration is used. Default is 0.
+fade-in effect the output video will have the same intensity as the input
+video, at the end of the fade-out transition the output video will be
+completely black. If both duration and nb_frames are specified, duration is
+used. Default is 0.
 @end table
 
 @subsection Examples
@@ -3778,7 +3875,7 @@ help the various algorithms of the filter, while keeping the output lossless
 or brightness/contrast adjustments can help.
 
 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
-and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
+and VIVTC/VFM (VapourSynth project). The latter is a light clone of TFM from
 which @code{fieldmatch} is based on. While the semantic and usage are very
 close, some behaviour and options names can differ.
 
-- 
1.8.1.2



More information about the ffmpeg-devel mailing list