@var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
@end example
+@section Notes on filtergraph escaping
+
+Some filter arguments require the use of special characters, typically
+@code{:} to separate key=value pairs in a named options list. In this
+case the user should perform a first level escaping when specifying
+the filter arguments. For example, consider the following literal
+string to be embedded in the @ref{drawtext} filter arguments:
+@example
+this is a 'string': may contain one, or more, special characters
+@end example
+
+Since @code{:} is special for the filter arguments syntax, it needs to
+be escaped, so you get:
+@example
+text=this is a \'string\'\: may contain one, or more, special characters
+@end example
+
+A second level of escaping is required when embedding the filter
+arguments in a filtergraph description, in order to escape all the
+filtergraph special characters. Thus the example above becomes:
+@example
+drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
+@end example
+
+Finally an additional level of escaping may be needed when writing the
+filtergraph description in a shell command, which depends on the
+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"
+@end example
+
+Sometimes, it might be more convenient to employ quoting in place of
+escaping. For example the string:
+@example
+Caesar: tu quoque, Brute, fili mi
+@end example
+
+Can be quoted in the filter arguments as:
+@example
+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
+
+See the @ref{quoting_and_escaping, Quoting and escaping} section for
+more information about the escaping and quoting rules adopted by
+FFmpeg.
+
@c man end FILTERGRAPH DESCRIPTION
@chapter Audio Filters
suffix for a planar sample format.
@var{channel_layout} specifies the channel layout, and can be a string
-or the corresponding number value defined in @file{libavutil/audioconvert.h}.
+or the corresponding number value defined in @file{libavutil/channel_layout.h}.
The special parameter "auto", signifies that the filter will
automatically select the output format depending on the output filter.
@section aresample
-Resample the input audio to the specified sample rate.
+Resample the input audio to the specified parameters. If none are specified
+then the filter will automatically convert between its input
+and output.
+
+This filter is also able to stretch/squeeze the audio data to make it match
+the timestamps or to inject silence / cut out audio to make it match the
+timestamps, do a combination of both or do neither.
+
+The filter accepts the following named parameters:
+@table @option
+
+@item min_comp
+Minimum difference between timestamps and audio data (in seconds) to trigger
+stretching/squeezing/filling or trimming of the data to make it match the
+timestamps. The default is that stretching/squeezing/filling and
+trimming is disabled (min_comp = infinite).
+
+@item min_hard_comp
+Minimum difference between timestamps and audio data (in seconds) to trigger
+adding/dropping samples to make it match the timestamps.
+This option effectively is a threshold to select between hard (trim/fill) and
+soft (squeeze/stretch) compensation. Note that all compensation is by default
+disabled through min_comp.
+The default is 0.1 seconds.
+
+@item max_soft_comp
+Maximum stretch/squeeze factor.
+Default value 0.
+
+@item tsf, internal_sample_fmt
+Internal sampling format.
+Default is automatic selection
+
+@item clev, center_mix_level
+center mix level, for rematrixing
+Default is 3.0dB
+
+@item slev, surround_mix_level
+surround mix level, for rematrixing
+Default is 3.0dB
+
+@item rmvol, rematrix_volume
+rematrix volume
+Default is 1.0
+
+@item lfe_mix_level
+Low frequency effects mix level.
+Default is 0
+
+@item matrix_encoding
+matrixed stereo encoding
+@table @option
+@item none
+No matrixed stereo encoding
+
+@item dolby
+Dolby matrixed stereo encoding
+
+@item dolby
+Dolby Pro Logic II matrixed stereo encoding
+@end table
+
+Default value is @code{none}.
-The filter accepts exactly one parameter, the output sample rate. If not
-specified then the filter will automatically convert between its input
-and output sample rates.
+@end table
For example, to resample the input audio to 44100Hz:
@example
sequential number of the input frame, starting from 0
@item pts
-presentation TimeStamp of the input frame, expressed as a number of
-time base units. The time base unit depends on the filter input pad, and
-is usually 1/@var{sample_rate}.
+Presentation timestamp of the input frame, in time base units; the time base
+depends on the filter input pad, and is usually 1/@var{sample_rate}.
@item pts_time
-presentation TimeStamp of the input frame, expressed as a number of
-seconds
+presentation timestamp of the input frame in seconds
@item pos
position of the frame in the input stream, -1 if this information in
unavailable and/or meaningless (for example in case of synthetic audio)
@item fmt
-sample format name
+sample format
@item chlayout
-channel layout description
-
-@item nb_samples
-number of samples (per each channel) contained in the filtered frame
+channel layout
@item rate
sample rate for the audio frame
+@item nb_samples
+number of samples (per channel) in the frame
+
@item checksum
-Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
+Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
+the data is treated as if all the planes were concatenated.
-@item plane_checksum
-Adler-32 checksum (printed in hexadecimal) for each input frame plane,
-expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5}
-@var{c6} @var{c7}]"
+@item plane_checksums
+A list of Adler-32 checksums for each data plane.
@end table
@section asplit
ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
@end example
-@section volume
-
-Adjust the input audio volume.
-
-The filter accepts exactly one parameter @var{vol}, which expresses
-how the audio volume will be increased or decreased.
-
-Output values are clipped to the maximum value.
-
-If @var{vol} is expressed as a decimal number, the output audio
-volume is given by the relation:
-@example
-@var{output_volume} = @var{vol} * @var{input_volume}
-@end example
-
-If @var{vol} is expressed as a decimal number followed by the string
-"dB", the value represents the requested change in decibels of the
-input audio power, and the output audio volume is given by the
-relation:
-@example
-@var{output_volume} = 10^(@var{vol}/20) * @var{input_volume}
-@end example
-
-Otherwise @var{vol} is considered an expression and its evaluated
-value is used for computing the output audio volume according to the
-first relation.
-
-Default value for @var{vol} is 1.0.
-
-@subsection Examples
-
-@itemize
-@item
-Half the input audio volume:
-@example
-volume=0.5
-@end example
-
-The above example is equivalent to:
-@example
-volume=1/2
-@end example
-
-@item
-Decrease input audio power by 12 decibels:
-@example
-volume=-12dB
-@end example
-@end itemize
-
-@section volumedetect
-
-Detect the volume of the input video.
-
-The filter has no parameters. The input is not modified. Statistics about
-the volume will be printed in the log when the input stream end is reached.
-
-In particular it will show the mean volume (root mean square), maximum
-volume (on a per-sample basis), and the beginning of an histogram of the
-registered volume values (from the maximum value to a cumulated 1/1000 of
-the samples).
-
-All volumes are in decibels relative to the maximum PCM value.
-
-Here is an excerpt of the output:
-@example
-[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
-[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
-[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
-[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
-[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
-[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
-[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
-[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
-[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
-@end example
-
-It means that:
-@itemize
-@item
-The mean square energy is approximately -27 dB, or 10^-2.7.
-@item
-The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
-@item
-There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
-@end itemize
-
-In other words, raising the volume by +4 dB does not cause any clipping,
-raising it by +5 dB causes clipping for 6 samples, etc.
-
@section asyncts
Synchronize audio data with timestamps by squeezing/stretching it and/or
dropping samples/adding silence when needed.
Default value 500.
@item first_pts
-Assume the first pts should be this value.
+Assume the first pts should be this value. The time base is 1 / sample rate.
This allows for padding/trimming at the start of stream. By default, no
assumption is made about the first frame's expected pts, so no padding or
trimming is done. For example, this could be set to 0 to pad the beginning with
-silence if an audio stream starts after the video stream.
+silence if an audio stream starts after the video stream or to trim any samples
+with a negative pts due to encoder delay.
@end table
Convert the audio sample format, sample rate and channel layout. This filter is
not meant to be used directly.
+@section volume
+
+Adjust the input audio volume.
+
+The filter accepts the following named parameters. If the key of the
+first options is omitted, the arguments are interpreted according to
+the following syntax:
+@example
+volume=@var{volume}:@var{precision}
+@end example
+
+@table @option
+
+@item volume
+Expresses how the audio volume will be increased or decreased.
+
+Output values are clipped to the maximum value.
+
+The output audio volume is given by the relation:
+@example
+@var{output_volume} = @var{volume} * @var{input_volume}
+@end example
+
+Default value for @var{volume} is 1.0.
+
+@item precision
+Set the mathematical precision.
+
+This determines which input sample formats will be allowed, which affects the
+precision of the volume scaling.
+
+@table @option
+@item fixed
+8-bit fixed-point; limits input sample format to U8, S16, and S32.
+@item float
+32-bit floating-point; limits input sample format to FLT. (default)
+@item double
+64-bit floating-point; limits input sample format to DBL.
+@end table
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Halve the input audio volume:
+@example
+volume=volume=0.5
+volume=volume=1/2
+volume=volume=-6.0206dB
+@end example
+
+In all the above example the named key for @option{volume} can be
+omitted, for example like in:
+@example
+volume=0.5
+@end example
+
+@item
+Increase input audio power by 6 decibels using fixed-point precision:
+@example
+volume=volume=6dB:precision=fixed
+@end example
+@end itemize
+
+@section volumedetect
+
+Detect the volume of the input video.
+
+The filter has no parameters. The input is not modified. Statistics about
+the volume will be printed in the log when the input stream end is reached.
+
+In particular it will show the mean volume (root mean square), maximum
+volume (on a per-sample basis), and the beginning of an histogram of the
+registered volume values (from the maximum value to a cumulated 1/1000 of
+the samples).
+
+All volumes are in decibels relative to the maximum PCM value.
+
+Here is an excerpt of the output:
+@example
+[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
+[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
+[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
+[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
+[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
+[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
+[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
+[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
+[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
+@end example
+
+It means that:
+@itemize
+@item
+The mean square energy is approximately -27 dB, or 10^-2.7.
+@item
+The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
+@item
+There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
+@end itemize
+
+In other words, raising the volume by +4 dB does not cause any clipping,
+raising it by +5 dB causes clipping for 6 samples, etc.
+
@c man end AUDIO FILTERS
@chapter Audio Sources
@item channel_layout
The channel layout of the incoming audio buffers.
Either a channel layout name from channel_layout_map in
-@file{libavutil/audioconvert.c} or its corresponding integer representation
-from the AV_CH_LAYOUT_* macros in @file{libavutil/audioconvert.h}
+@file{libavutil/channel_layout.c} or its corresponding integer representation
+from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
@end table
is "stereo".
Check the channel_layout_map definition in
-@file{libavcodec/audioconvert.c} for the mapping between strings and
+@file{libavutil/channel_layout.c} for the mapping between strings and
channel layout values.
@item nb_samples, n
@section ass
-Draw ASS (Advanced Substation Alpha) subtitles on top of input video
-using the libass library.
-
-To enable compilation of this filter you need to configure FFmpeg with
-@code{--enable-libass}.
-
-This filter accepts the following named options, expressed as a
-sequence of @var{key}=@var{value} pairs, separated by ":".
-
-@table @option
-@item filename, f
-Set the filename of the ASS file to read. It must be specified.
-
-@item original_size
-Specify the size of the original video, the video for which the ASS file
-was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
-necessary to correctly scale the fonts if the aspect ratio has been changed.
-@end table
-
-If the first key is not specified, it is assumed that the first value
-specifies the @option{filename}.
-
-For example, to render the file @file{sub.ass} on top of the input
-video, use the command:
-@example
-ass=sub.ass
-@end example
-
-which is equivalent to:
-@example
-ass=filename=sub.ass
-@end example
+Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
+and libavformat to work. On the other hand, it is limited to ASS (Advanced
+Substation Alpha) subtitles files.
@section bbox
Draw a colored box on the input image.
-It accepts the syntax:
-@example
-drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
-@end example
+The filter accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
-@table @option
+The description of the accepted parameters follows.
+@table @option
@item x, y
Specify the top left corner coordinates of the box. Default to 0.
-@item width, height
+@item width, w
+@item height, h
Specify the width and height of the box, if 0 they are interpreted as
the input width and height. Default to 0.
-@item color
+@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.
+(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
+video with inverted luma.
+
+@item thickness, t
+Set the thickness of the box edge. Default value is @code{4}.
@end table
-Follow some examples:
+If the key of the first options is omitted, the arguments are
+interpreted according to the following syntax:
+@example
+drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}:@var{thickness}
+@end example
+
+Some examples follow:
+@itemize
+@item
+Draw a black box around the edge of the input image:
@example
-# draw a black box around the edge of the input image
drawbox
+@end example
+
+@item
+Draw a box with color red and an opacity of 50%:
+@example
+drawbox=10:20:200:60:red@@0.5
+@end example
+
+The previous example can be specified as:
+@example
+drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
+@end example
-# draw a box with color red and an opacity of 50%
-drawbox=10:20:200:60:red@@0.5"
+@item
+Fill the box with pink color:
+@example
+drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
@end example
+@end itemize
+@anchor{drawtext}
@section drawtext
Draw text string or text from specified file on top of video using the
To enable compilation of this filter you need to configure FFmpeg with
@code{--enable-libfreetype}.
-The filter also recognizes strftime() sequences in the provided text
-and expands them accordingly. Check the documentation of strftime().
+@subsection Syntax
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
separated by ":".
See below for the list of accepted constants and functions.
+@item expansion
+Select how the @var{text} is expanded. Can be either @code{none},
+@code{strftime} (default for compatibity reasons but deprecated) or
+@code{normal}. See the @ref{drawtext_expansion, Text expansion} section
+below for details.
+
@item fix_bounds
If true, check and fix text coords to avoid clipping.
If both @var{text} and @var{textfile} are specified, an error is thrown.
+@item reload
+If set to 1, the @var{textfile} will be reloaded before each frame.
+Be sure to update it atomically, or it may be read partially, or even fail.
+
@item x, y
The expressions which specify the offsets where text will be drawn
within the video frame. They are relative to the top/left border of the
If libavfilter was built with @code{--enable-fontconfig}, then
@option{fontfile} can be a fontconfig pattern or omitted.
-Some examples follow.
+@anchor{drawtext_expansion}
+@subsection Text expansion
-@itemize
+If @option{expansion} is set to @code{strftime} (which is the default for
+now), the filter recognizes strftime() sequences in the provided text and
+expands them accordingly. Check the documentation of strftime(). This
+feature is deprecated.
-@item
+If @option{expansion} is set to @code{none}, the text is printed verbatim.
+
+If @option{expansion} is set to @code{normal} (which will be the default),
+the following expansion mechanism is used.
+
+The backslash character '\', followed by any character, always expands to
+the second character.
+
+Sequence of the form @code{%@{...@}} are expanded. The text between the
+braces is a function name, possibly followed by arguments separated by ':'.
+If the arguments contain special characters or delimiters (':' or '@}'),
+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,
+that makes up to four levels of escaping; using a text file avoids these
+problems.
+
+The following functions are available:
+
+@table @command
+
+@item expr, e
+The expression evaluation result.
+
+It must take one argument specifying the expression to be evaluated,
+which accepts the same constants and functions as the @var{x} and
+@var{y} values. Note that not all constants should be used, for
+example the text size is not known when evaluating the expression, so
+the constants @var{text_w} and @var{text_h} will have an undefined
+value.
+
+@item gmtime
+The time at which the filter is running, expressed in UTC.
+It can accept an argument: a strftime() format string.
+
+@item localtime
+The time at which the filter is running, expressed in the local time zone.
+It can accept an argument: a strftime() format string.
+
+@item n, frame_num
+The frame number, starting from 0.
+
+@item pts
+The timestamp of the current frame, in seconds, with microsecond accuracy.
+
+@end table
+
+@subsection Examples
+
+Some examples follow.
+
+@itemize
+
+@item
Draw "Test Text" with font FreeSerif, using the default values for the
optional parameters.
drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
@end example
+@item
+Print the date of a real-time encoding (see strftime(3)):
+@example
+drawtext='fontfile=FreeSans.ttf:expansion=normal:text=%@{localtime:%a %b %d %Y@}'
+@end example
+
@end itemize
For more information about libfreetype, check:
fade=in:0:25:alpha=1
@end example
+@section field
+
+Extract a single field from an interlaced image using stride
+arithmetic to avoid wasting CPU time. The output frames are marked as
+non-interlaced.
+
+This filter accepts the following named options:
+@table @option
+@item type
+Specify whether to extract the top (if the value is @code{0} or
+@code{top}) or the bottom field (if the value is @code{1} or
+@code{bottom}).
+@end table
+
+If the option key is not specified, the first value sets the @var{type}
+option. For example:
+@example
+field=bottom
+@end example
+
+is equivalent to:
+@example
+field=type=bottom
+@end example
+
@section fieldorder
Transform the field order of the input video.
@table @option
@item fps
-Desired output framerate.
+Desired output framerate. The default is @code{25}.
@item round
-Rounding method. The default is @code{near}.
+Rounding method.
+Possible values are:
+@table @option
+@item zero
+zero round towards 0
+@item inf
+round away from 0
+@item down
+round towards -infinity
+@item up
+round towards +infinity
+@item near
+round to nearest
@end table
+The default is @code{near}.
+
+@end table
+
+Alternatively, the options can be specified as a flat string:
+@var{fps}[:@var{round}].
+
+See also the @ref{setpts} filter.
@section framestep
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
@end example
-@var{filter_name} is the name to the frei0r effect to load. If the
+@var{filter_name} is the name of the frei0r effect to load. If the
environment variable @env{FREI0R_PATH} is defined, the frei0r effect
-is searched in each one of the directories specified by the colon
-separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
-paths, which are in this order: @file{HOME/.frei0r-1/lib/},
-@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
+is searched in each one of the directories specified by the colon (or
+semicolon on Windows platforms) separated list in @env{FREIOR_PATH},
+otherwise in the standard frei0r paths, which are in this order:
+@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
+@file{/usr/lib/frei0r-1/}.
@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
for the frei0r effect.
@end example
@item
-Apply the colordistance effect, takes a color as first parameter:
+Apply the colordistance effect, take a color as first parameter:
@example
frei0r=colordistance:0.2/0.3/0.4
frei0r=colordistance:violet
For more information see:
@url{http://frei0r.dyne.org}
+@section geq
+
+The filter takes one, two or three equations as parameter, separated by ':'.
+The first equation is mandatory and applies to the luma plane. The two
+following are respectively for chroma blue and chroma red planes.
+
+The filter syntax allows named parameters:
+
+@table @option
+@item lum_expr
+the luminance expression
+@item cb_expr
+the chrominance blue expression
+@item cr_expr
+the chrominance red expression
+@end table
+
+If one of the chrominance expression is not defined, it falls back on the other
+one. If none of them are specified, they will evaluate the luminance
+expression.
+
+The expressions can use the following variables and functions:
+
+@table @option
+@item N
+The sequential number of the filtered frame, starting from @code{0}.
+
+@item X, Y
+The coordinates of the current sample.
+
+@item W, H
+The width and height of the image.
+
+@item SW, SH
+Width and height scale depending on the currently filtered plane. It is the
+ratio between the corresponding luma plane number of pixels and the current
+plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
+@code{0.5,0.5} for chroma planes.
+
+@item T
+Time of the current frame, expressed in seconds.
+
+@item p(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the current
+plane.
+
+@item lum(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the luminance
+plane.
+
+@item cb(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+blue-difference chroma plane.
+
+@item cr(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+red-difference chroma plane.
+@end table
+
+For functions, if @var{x} and @var{y} are outside the area, the value will be
+automatically clipped to the closer edge.
+
+Some examples follow:
+
+@itemize
+@item
+Flip the image horizontally:
+@example
+geq=p(W-X\,Y)
+@end example
+
+@item
+Generate a bidimensional sine wave, with angle @code{PI/3} and a
+wavelength of 100 pixels:
+@example
+geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
+@end example
+
+@item
+Generate a fancy enigmatic moving light:
+@example
+nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
+@end example
+@end itemize
+
@section gradfun
Fix the banding artifacts that are sometimes introduced into nearly flat
The list of the currently supported filters follows:
@table @var
-@item denoise3d
@item detc
@item dint
@item divtc
@item dsize
@item eq2
@item eq
-@item field
@item fil
-@item fixpts
@item fspp
-@item geq
@item harddup
-@item hqdn3d
@item il
@item ilpack
@item ivtc
@item mcdeint
@item noise
@item ow
-@item palette
@item perspective
@item phase
@item pp7
@item pullup
@item qp
-@item rectangle
@item sab
@item softpulldown
@item softskip
@item spp
@item telecine
-@item tile
@item tinterlace
@item unsharp
@item uspp
-@item yuvcsp
-@item yvu9
@end table
The parameter syntax and behavior for the listed filters are the same
@section scale
-Scale (resize) the input video to @var{width}:@var{height}[:@var{interl}=@{1|-1@}] and/or convert the image format.
+Scale (resize) the input video, using the libswscale library.
The scale filter forces the output display aspect ratio to be the same
of the input, by changing the output sample aspect ratio.
-The parameters @var{width} and @var{height} are expressions containing
-the following constants:
+This filter accepts a list of named options in the form of
+@var{key}=@var{value} pairs separated by ":". If the key for the first
+two options is not specified, the assumed keys for the first two
+values are @code{w} and @code{h}. If the first option has no key and
+can be interpreted like a video size specification, it will be used
+to set the video size.
+
+A description of the accepted options follows.
+
+@table @option
+@item width, w
+Set the video width expression, default value is @code{iw}. See below
+for the list of accepted constants.
+
+@item height, h
+Set the video heiht expression, default value is @code{ih}.
+See below for the list of accepted constants.
+
+@item interl
+Set the interlacing. It accepts the following values:
+
+@table @option
+@item 1
+force interlaced aware scaling
+
+@item 0
+do not apply interlaced scaling
+
+@item -1
+select interlaced aware scaling depending on whether the source frames
+are flagged as interlaced or not
+@end table
+
+Default value is @code{0}.
+
+@item flags
+Set libswscale scaling flags. If not explictly specified the filter
+applies a bilinear scaling algorithm.
+
+@item size, s
+Set the video size, the value must be a valid abbreviation or in the
+form @var{width}x@var{height}.
+@end table
+
+The values of the @var{w} and @var{h} options are expressions
+containing the following constants:
@table @option
@item in_w, in_h
use, for the respective output size, a value that maintains the aspect
ratio of the input image.
-The default value of @var{width} and @var{height} is 0.
+@subsection Examples
-Valid values for the optional parameter @var{interl} are:
+@itemize
+@item
+Scale the input video to a size of 200x100:
+@example
+scale=200:100
+@end example
-@table @option
-@item 1
-force interlaced aware scaling
+This is equivalent to:
+@example
+scale=w=200:h=100
+@end example
-@item -1
-select interlaced aware scaling depending on whether the source frames
-are flagged as interlaced or not
-@end table
+or:
+@example
+scale=200x100
+@end example
-Unless @var{interl} is set to one of the above options, interlaced scaling will not be used.
+@item
+Specify a size abbreviation for the output size:
+@example
+scale=qcif
+@end example
-Some examples follow:
+which can also be written as:
@example
-# scale the input video to a size of 200x100.
-scale=200:100
+scale=size=qcif
+@end example
-# scale the input to 2x
+@item
+Scale the input to 2x:
+@example
scale=2*iw:2*ih
-# the above is the same as
+@end example
+
+@item
+The above is the same as:
+@example
scale=2*in_w:2*in_h
+@end example
-# scale the input to 2x with forced interlaced scaling
+@item
+Scale the input to 2x with forced interlaced scaling:
+@example
scale=2*iw:2*ih:interl=1
+@end example
-# scale the input to half size
+@item
+Scale the input to half size:
+@example
scale=iw/2:ih/2
+@end example
-# increase the width, and set the height to the same size
+@item
+Increase the width, and set the height to the same size:
+@example
scale=3/2*iw:ow
+@end example
-# seek for Greek harmony
+@item
+Seek for Greek harmony:
+@example
scale=iw:1/PHI*iw
scale=ih*PHI:ih
+@end example
-# increase the height, and set the width to 3/2 of the height
+@item
+Increase the height, and set the width to 3/2 of the height:
+@example
scale=3/2*oh:3/5*ih
-
-# increase the size, but make the size a multiple of the chroma
-scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
-
-# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
-scale='min(500\, iw*3/2):-1'
@end example
-@section select
-Select frames to pass in output.
-
-It accepts in input an expression, which is evaluated for each input
-frame. If the expression is evaluated to a non-zero value, the frame
-is selected and passed to the output, otherwise it is discarded.
-
-The expression can contain the following constants:
-
-@table @option
-@item n
-the sequential number of the filtered frame, starting from 0
-
-@item selected_n
-the sequential number of the selected frame, starting from 0
-
-@item prev_selected_n
-the sequential number of the last selected frame, NAN if undefined
-
-@item TB
-timebase of the input timestamps
-
-@item pts
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in @var{TB} units, NAN if undefined
-
-@item t
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in seconds, NAN if undefined
-
-@item prev_pts
-the PTS of the previously filtered video frame, NAN if undefined
-
-@item prev_selected_pts
-the PTS of the last previously filtered video frame, NAN if undefined
-
-@item prev_selected_t
-the PTS of the last previously selected video frame, NAN if undefined
-
-@item start_pts
-the PTS of the first video frame in the video, NAN if undefined
-
-@item start_t
-the time of the first video frame in the video, NAN if undefined
-
-@item pict_type
-the type of the filtered frame, can assume one of the following
-values:
-@table @option
-@item I
-@item P
-@item B
-@item S
-@item SI
-@item SP
-@item BI
-@end table
-
-@item interlace_type
-the frame interlace type, can assume one of the following values:
-@table @option
-@item PROGRESSIVE
-the frame is progressive (not interlaced)
-@item TOPFIRST
-the frame is top-field-first
-@item BOTTOMFIRST
-the frame is bottom-field-first
-@end table
-
-@item key
-1 if the filtered frame is a key-frame, 0 otherwise
-
-@item pos
-the position in the file of the filtered frame, -1 if the information
-is not available (e.g. for synthetic video)
-
-@item scene
-value between 0 and 1 to indicate a new scene; a low value reflects a low
-probability for the current frame to introduce a new scene, while a higher
-value means the current frame is more likely to be one (see the example below)
-
-@end table
-
-The default value of the select expression is "1".
-
-Some examples follow:
-
+@item
+Increase the size, but make the size a multiple of the chroma:
@example
-# select all frames in input
-select
-
-# the above is the same as:
-select=1
-
-# skip all frames:
-select=0
-
-# select only I-frames
-select='eq(pict_type\,I)'
-
-# select one frame every 100
-select='not(mod(n\,100))'
-
-# select only frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)'
-
-# select only I frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
-
-# select frames with a minimum distance of 10 seconds
-select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
+scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
@end example
-Complete example to create a mosaic of the first scenes:
-
+@item
+Increase the width to a maximum of 500 pixels, keep the same input
+aspect ratio:
@example
-ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+scale='min(500\, iw*3/2):-1'
@end example
-
-Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
-choice.
+@end itemize
@section setdar, setsar
corresponding property, which affects how the frame is treated by
following filters (e.g. @code{fieldorder} or @code{yadif}).
-It accepts a string parameter, which can assume the following values:
+This filter accepts a single option @option{mode}, which can be
+specified either by setting @code{mode=VALUE} or setting the value
+alone. Available values are:
+
@table @samp
@item auto
Keep the same field property.
expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
@end table
-@section slicify
-
-Pass the images of input video on to next video filter as multiple
-slices.
-
-@example
-ffmpeg -i in.avi -vf "slicify=32" out.avi
-@end example
-
-The filter accepts the slice height as parameter. If the parameter is
-not specified it will use the default value of 16.
-
-Adding this in the beginning of filter chains should make filtering
-faster due to better use of the memory cache.
-
@section smartblur
Blur the input video without impacting the outlines.
image, a value included in [0,30] will filter flat areas and a value
included in [-30,0] will filter edges.
+@anchor{subtitles}
+@section subtitles
+
+Draw subtitles on top of input video using the libass library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libass}. This filter also requires a build with libavcodec and
+libavformat to convert the passed subtitles file to ASS (Advanced Substation
+Alpha) subtitles format.
+
+This filter accepts the following named options, expressed as a
+sequence of @var{key}=@var{value} pairs, separated by ":".
+
+@table @option
+@item filename, f
+Set the filename of the subtitle file to read. It must be specified.
+
+@item original_size
+Specify the size of the original video, the video for which the ASS file
+was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
+necessary to correctly scale the fonts if the aspect ratio has been changed.
+@end table
+
+If the first key is not specified, it is assumed that the first value
+specifies the @option{filename}.
+
+For example, to render the file @file{sub.srt} on top of the input
+video, use the command:
+@example
+subtitles=sub.srt
+@end example
+
+which is equivalent to:
+@example
+subtitles=filename=sub.srt
+@end example
+
@section split
Split input video into several identical outputs.
Tile several successive frames together.
-It accepts as argument the tile size (i.e. the number of lines and columns)
-in the form "@var{w}x@var{h}".
+It accepts a list of options in the form of @var{key}=@var{value} pairs
+separated by ":". A description of the accepted options follows.
+
+@table @option
+
+@item layout
+Set the grid size (i.e. the number of lines and columns) in the form
+"@var{w}x@var{h}".
+
+@item margin
+Set the outer border margin in pixels.
+
+@item padding
+Set the inner border thickness (i.e. the number of pixels between frames). For
+more advanced padding options (such as having different values for the edges),
+refer to the pad video filter.
+
+@item nb_frames
+Set the maximum number of frames to render in the given area. It must be less
+than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
+the area will be used.
+
+@end table
+
+Alternatively, the options can be specified as a flat string:
+
+@var{layout}[:@var{nb_frames}[:@var{margin}[:@var{padding}]]]
For example, produce 8×8 PNG tiles of all keyframes (@option{-skip_frame
nokey}) in a movie:
duplicating each output frame to accomodate the originally detected frame
rate.
+Another example to display @code{5} pictures in an area of @code{3x2} frames,
+with @code{7} pixels between them, and @code{2} pixels of initial margin, using
+mixed flat and named options:
+@example
+tile=3x2:nb_frames=5:padding=7:margin=2
+@end example
+
@section tinterlace
Perform various types of temporal field interlacing.
Frames are counted starting from 1, so the first input frame is
considered odd.
-This filter accepts a single parameter specifying the mode. Available
-modes are:
+This filter accepts a single option @option{mode} specifying the mode,
+which can be specified either by specyfing @code{mode=VALUE} either
+specifying the value alone. Available values are:
@table @samp
@item merge, 0
If the input content is to be ignored, @code{nullsrc} can be used. The
following command generates noise in the luminance plane by employing
-the @code{mp=geq} filter:
+the @code{geq} filter:
@example
-nullsrc=s=256x256, mp=geq=random(1)*255:128:128
+nullsrc=s=256x256, geq=random(1)*255:128:128
@end example
@c man end VIDEO SOURCES
Below is a description of the currently available multimedia filters.
+@section aselect, select
+Select frames to pass in output.
+
+These filters accept a single option @option{expr} or @option{e}
+specifying the select expression, which can be specified either by
+specyfing @code{expr=VALUE} or specifying the expression
+alone.
+
+The select expression is evaluated for each input frame. If the
+evaluation result is a non-zero value, the frame is selected and
+passed to the output, otherwise it is discarded.
+
+The expression can contain the following constants:
+
+@table @option
+@item n
+the sequential number of the filtered frame, starting from 0
+
+@item selected_n
+the sequential number of the selected frame, starting from 0
+
+@item prev_selected_n
+the sequential number of the last selected frame, NAN if undefined
+
+@item TB
+timebase of the input timestamps
+
+@item pts
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in @var{TB} units, NAN if undefined
+
+@item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+@item prev_pts
+the PTS of the previously filtered video frame, NAN if undefined
+
+@item prev_selected_pts
+the PTS of the last previously filtered video frame, NAN if undefined
+
+@item prev_selected_t
+the PTS of the last previously selected video frame, NAN if undefined
+
+@item start_pts
+the PTS of the first video frame in the video, NAN if undefined
+
+@item start_t
+the time of the first video frame in the video, NAN if undefined
+
+@item pict_type @emph{(video only)}
+the type of the filtered frame, can assume one of the following
+values:
+@table @option
+@item I
+@item P
+@item B
+@item S
+@item SI
+@item SP
+@item BI
+@end table
+
+@item interlace_type @emph{(video only)}
+the frame interlace type, can assume one of the following values:
+@table @option
+@item PROGRESSIVE
+the frame is progressive (not interlaced)
+@item TOPFIRST
+the frame is top-field-first
+@item BOTTOMFIRST
+the frame is bottom-field-first
+@end table
+
+@item consumed_sample_n @emph{(audio only)}
+the number of selected samples before the current frame
+
+@item samples_n @emph{(audio only)}
+the number of samples in the current frame
+
+@item sample_rate @emph{(audio only)}
+the input sample rate
+
+@item key
+1 if the filtered frame is a key-frame, 0 otherwise
+
+@item pos
+the position in the file of the filtered frame, -1 if the information
+is not available (e.g. for synthetic video)
+
+@item scene @emph{(video only)}
+value between 0 and 1 to indicate a new scene; a low value reflects a low
+probability for the current frame to introduce a new scene, while a higher
+value means the current frame is more likely to be one (see the example below)
+
+@end table
+
+The default value of the select expression is "1".
+
+@subsection Examples
+
+@itemize
+@item
+Select all frames in input:
+@example
+select
+@end example
+
+The example above is the same as:
+@example
+select=1
+@end example
+
+@item
+Skip all frames:
+@example
+select=0
+@end example
+
+@item
+Select only I-frames:
+@example
+select='eq(pict_type\,I)'
+@end example
+
+@item
+Select one frame every 100:
+@example
+select='not(mod(n\,100))'
+@end example
+
+@item
+Select only frames contained in the 10-20 time interval:
+@example
+select='gte(t\,10)*lte(t\,20)'
+@end example
+
+@item
+Select only I frames contained in the 10-20 time interval:
+@example
+select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
+@end example
+
+@item
+Select frames with a minimum distance of 10 seconds:
+@example
+select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
+@end example
+
+@item
+Use aselect to select only audio frames with samples number > 100:
+@example
+aselect='gt(samples_n\,100)'
+@end example
+
+@item
+Create a mosaic of the first scenes:
+@example
+ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+@end example
+
+Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
+choice.
+@end itemize
+
@section asendcmd, sendcmd
Send commands to filters in the filtergraph.
@end example
@end itemize
+@anchor{setpts}
@section asetpts, setpts
Change the PTS (presentation timestamp) of the input frames.
Set the number of output audio streams, that is also the number of video
streams in each segment. Default is 0.
+@item unsafe
+Activate unsafe mode: do not fail if segments have a different format.
+
@end table
The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
projects / ffmpeg / blobdiff