information:
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
-Follows the list of supported libopencv filters.
+Follows the list of supported libopencv filters.
+
+@anchor{dilate}
+@subsection dilate
+
+Dilate an image by using a specific structuring element.
+This filter corresponds to the libopencv function @code{cvDilate}.
+
+It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
+
+@var{struct_el} represents a structuring element, and has the syntax:
+@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
+
+@var{cols} and @var{rows} represent the number of columns and rows of
+the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
+point, and @var{shape} the shape for the structuring element, and
+can be one of the values "rect", "cross", "ellipse", "custom".
+
+If the value for @var{shape} is "custom", it must be followed by a
+string of the form "=@var{filename}". The file with name
+@var{filename} is assumed to represent a binary image, with each
+printable character corresponding to a bright pixel. When a custom
+@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
+or columns and rows of the read file are assumed instead.
+
+The default value for @var{struct_el} is "3x3+0x0/rect".
+
+@var{nb_iterations} specifies the number of times the transform is
+applied to the image, and defaults to 1.
+
+Follow some example:
+@example
+# use the default values
+ocv=dilate
+
+# dilate using a structuring element with a 5x5 cross, iterate two times
+ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
+
+# read the shape from the file diamond.shape, iterate two times
+# the file diamond.shape may contain a pattern of characters like this:
+# *
+# ***
+# *****
+# ***
+# *
+# the specified cols and rows are ignored (but not the anchor point coordinates)
+ocv=dilate:0x0+2x2/custom=diamond.shape|2
+@end example
+
+@subsection erode
+
+Erode an image by using a specific structuring element.
+This filter corresponds to the libopencv function @code{cvErode}.
+
+The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
+with the same syntax and semantics as the @ref{dilate} filter.
+
+@subsection smooth
+
+Smooth the input video.
+
+The filter takes the following parameters:
+@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
+
+@var{type} is the type of smooth filter to apply, and can be one of
+the following values: "blur", "blur_no_scale", "median", "gaussian",
+"bilateral". The default value is "gaussian".
+
+@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
+parameters whose meanings depend on smooth type. @var{param1} and
+@var{param2} accept integer positive values or 0, @var{param3} and
+@var{param4} accept float values.
+
+The default value for @var{param1} is 3, the default value for the
+other parameters is 0.
+
+These parameters correspond to the parameters assigned to the
+libopencv function @code{cvSmooth}.
+
+@anchor{overlay}
+@section overlay
+
+Overlay one video on top of another.
+
+It takes two inputs and one output, the first input is the "main"
+video on which the second input is overlayed.
+
+This filter accepts the following parameters:
+
+A description of the accepted options follows.
+
+@table @option
+@item x
+@item y
+Set the expression for the x and y coordinates of the overlayed video
+on the main video. Default value is "0" for both expressions. In case
+the expression is invalid, it is set to a huge value (meaning that the
+overlay will not be displayed within the output visible area).
+
+@item eval
+Set when the expressions for @option{x}, and @option{y} are evaluated.
+
+It accepts the following values:
+@table @samp
+@item init
+only evaluate expressions once during the filter initialization or
+when a command is processed
+
+@item frame
+evaluate expressions for each incoming frame
+@end table
+
+Default value is @samp{frame}.
+
+@item shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+
+@item format
+Set the format for the output video.
+
+It accepts the following values:
+@table @samp
+@item yuv420
+force YUV420 output
+
+@item yuv444
+force YUV444 output
+
+@item rgb
+force RGB output
+@end table
+
+Default value is @samp{yuv420}.
+
+@item rgb @emph{(deprecated)}
+If set to 1, force the filter to accept inputs in the RGB
+color space. Default value is 0. This option is deprecated, use
+@option{format} instead.
+
+@item repeatlast
+If set to 1, force the filter to draw the last overlay frame over the
+main input until the end of the stream. A value of 0 disables this
+behavior. Default value is 1.
+@end table
+
+The @option{x}, and @option{y} expressions can contain the following
+parameters.
+
+@table @option
+@item main_w, W
+@item main_h, H
+main input width and height
+
+@item overlay_w, w
+@item overlay_h, h
+overlay input width and height
+
+@item x
+@item y
+the computed values for @var{x} and @var{y}. They are evaluated for
+each new frame.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values of the output
+format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
+@var{vsub} is 1.
+
+@item n
+the number of input frame, starting from 0
+
+@item pos
+the position in the file of the input frame, NAN if unknown
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+@end table
+
+Note that the @var{n}, @var{pos}, @var{t} variables are available only
+when evaluation is done @emph{per frame}, and will evaluate to NAN
+when @option{eval} is set to @samp{init}.
+
+Be aware that frames are taken from each input video in timestamp
+order, hence, if their initial timestamps differ, it is a good idea
+to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
+have them begin in the same zero timestamp, as it does the example for
+the @var{movie} filter.
+
+You can chain together more overlays but you should test the
+efficiency of such approach.
+
+@subsection Commands
+
+This filter supports the following commands:
+@table @option
+@item x
+@item y
+Modify the x and y of the overlay input.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw the overlay at 10 pixels from the bottom right corner of the main
+video:
+@example
+overlay=main_w-overlay_w-10:main_h-overlay_h-10
+@end example
+
+Using named options the example above becomes:
+@example
+overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
+@end example
+
+@item
+Insert a transparent PNG logo in the bottom left corner of the input,
+using the @command{ffmpeg} tool with the @code{-filter_complex} option:
+@example
+ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
+@end example
+
+@item
+Insert 2 different transparent PNG logos (second logo on bottom
+right corner) using the @command{ffmpeg} tool:
+@example
+ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
+@end example
+
+@item
+Add a transparent color layer on top of the main video, @code{WxH}
+must specify the size of the main input to the overlay filter:
+@example
+color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
+@end example
+
+@item
+Play an original video and a filtered version (here with the deshake
+filter) side by side using the @command{ffplay} tool:
+@example
+ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
+@end example
+
+The above command is the same as:
+@example
+ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
+@end example
+
+@item
+Make a sliding overlay appearing from the left to the right top part of the
+screen starting since time 2:
+@example
+overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
+@end example
+
+@item
+Compose output by putting two input videos side to side:
+@example
+ffmpeg -i left.avi -i right.avi -filter_complex "
+nullsrc=size=200x100 [background];
+[0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
+[1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
+[background][left] overlay=shortest=1 [background+left];
+[background+left][right] overlay=shortest=1:x=100 [left+right]
+"
+@end example
+
+@item
+Chain several overlays in cascade:
+@example
+nullsrc=s=200x200 [bg];
+testsrc=s=100x100, split=4 [in0][in1][in2][in3];
+[in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
+[in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
+[in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
+[in3] null, [mid2] overlay=100:100 [out0]
+@end example
+
+@end itemize
+
+@section owdenoise
+
+Apply Overcomplete Wavelet denoiser.
+
+The filter accepts the following options:
+
+@table @option
+@item depth
+Set depth.
+
+Larger depth values will denoise lower frequency components more, but
+slow down filtering.
+
+Must be an int in the range 8-16, default is @code{8}.
+
+@item luma_strength, ls
+Set luma strength.
+
+Must be a double value in the range 0-1000, default is @code{1.0}.
+
+@item chroma_strength, cs
+Set chroma strength.
+
+Must be a double value in the range 0-1000, default is @code{1.0}.
+@end table
+
+@section pad
+
+Add paddings to the input image, and place the original input at the
+given coordinates @var{x}, @var{y}.
+
+This filter accepts the following parameters:
+
+@table @option
+@item width, w
+@item height, h
+Specify an expression for the size of the output image with the
+paddings added. If the value for @var{width} or @var{height} is 0, the
+corresponding input size is used for the output.
+
+The @var{width} expression can reference the value set by the
+@var{height} expression, and vice versa.
+
+The default value of @var{width} and @var{height} is 0.
+
+@item x
+@item y
+Specify an expression for the offsets where to place the input image
+in the padded area with respect to the top/left border of the output
+image.
+
+The @var{x} expression can reference the value set by the @var{y}
+expression, and vice versa.
+
+The default value of @var{x} and @var{y} is 0.
+
+@item color
+Specify the color of the padded area. For the syntax of this option,
+check the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{color} is "black".
+@end table
+
+The value for the @var{width}, @var{height}, @var{x}, and @var{y}
+options are expressions containing the following constants:
+
+@table @option
+@item in_w
+@item in_h
+the input video width and height
+
+@item iw
+@item ih
+same as @var{in_w} and @var{in_h}
+
+@item out_w
+@item out_h
+the output width and height, that is the size of the padded area as
+specified by the @var{width} and @var{height} expressions
+
+@item ow
+@item oh
+same as @var{out_w} and @var{out_h}
+
+@item x
+@item y
+x and y offsets as specified by the @var{x} and @var{y}
+expressions, or NAN if not yet specified
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Add paddings with color "violet" to the input video. Output video
+size is 640x480, the top-left corner of the input video is placed at
+column 0, row 40:
+@example
+pad=640:480:0:40:violet
+@end example
+
+The example above is equivalent to the following command:
+@example
+pad=width=640:height=480:x=0:y=40:color=violet
+@end example
+
+@item
+Pad the input to get an output with dimensions increased by 3/2,
+and put the input video at the center of the padded area:
+@example
+pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+Pad the input to get a squared output with size equal to the maximum
+value between the input width and height, and put the input video at
+the center of the padded area:
+@example
+pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+Pad the input to get a final w/h ratio of 16:9:
+@example
+pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+In case of anamorphic video, in order to set the output display aspect
+correctly, it is necessary to use @var{sar} in the expression,
+according to the relation:
+@example
+(ih * X / ih) * sar = output_dar
+X = output_dar / sar
+@end example
+
+Thus the previous example needs to be modified to:
+@example
+pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+Double output size and put the input video in the bottom-right
+corner of the output padded area:
+@example
+pad="2*iw:2*ih:ow-iw:oh-ih"
+@end example
+@end itemize
+
+@section perspective
+
+Correct perspective of video not recorded perpendicular to the screen.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item x0
+@item y0
+@item x1
+@item y1
+@item x2
+@item y2
+@item x3
+@item y3
+Set coordinates expression for top left, top right, bottom left and bottom right corners.
+Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
+
+The expressions can use the following variables:
+
+@table @option
+@item W
+@item H
+the width and height of video frame.
+@end table
+
+@item interpolation
+Set interpolation for perspective correction.
+
+It accepts the following values:
+@table @samp
+@item linear
+@item cubic
+@end table
+
+Default value is @samp{linear}.
+@end table
+
+@section phase
+
+Delay interlaced video by one field time so that the field order changes.
+
+The intended use is to fix PAL movies that have been captured with the
+opposite field order to the film-to-video transfer.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item mode
+Set phase mode.
+
+It accepts the following values:
+@table @samp
+@item t
+Capture field order top-first, transfer bottom-first.
+Filter will delay the bottom field.
+
+@item b
+Capture field order bottom-first, transfer top-first.
+Filter will delay the top field.
+
+@item p
+Capture and transfer with the same field order. This mode only exists
+for the documentation of the other options to refer to, but if you
+actually select it, the filter will faithfully do nothing.
+
+@item a
+Capture field order determined automatically by field flags, transfer
+opposite.
+Filter selects among @samp{t} and @samp{b} modes on a frame by frame
+basis using field flags. If no field information is available,
+then this works just like @samp{u}.
+
+@item u
+Capture unknown or varying, transfer opposite.
+Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
+analyzing the images and selecting the alternative that produces best
+match between the fields.
+
+@item T
+Capture top-first, transfer unknown or varying.
+Filter selects among @samp{t} and @samp{p} using image analysis.
+
+@item B
+Capture bottom-first, transfer unknown or varying.
+Filter selects among @samp{b} and @samp{p} using image analysis.
+
+@item A
+Capture determined by field flags, transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
+image analysis. If no field information is available, then this works just
+like @samp{U}. This is the default mode.
+
+@item U
+Both capture and transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
+@end table
+@end table
+
+@section pixdesctest
+
+Pixel format descriptor test filter, mainly useful for internal
+testing. The output video should be equal to the input video.
+
+For example:
+@example
+format=monow, pixdesctest
+@end example
+
+can be used to test the monowhite pixel format descriptor definition.
+
+@section pp
+
+Enable the specified chain of postprocessing subfilters using libpostproc. This
+library should be automatically selected with a GPL build (@code{--enable-gpl}).
+Subfilters must be separated by '/' and can be disabled by prepending a '-'.
+Each subfilter and some options have a short and a long name that can be used
+interchangeably, i.e. dr/dering are the same.
+
+The filters accept the following options:
+
+@table @option
+@item subfilters
+Set postprocessing subfilters string.
+@end table
+
+All subfilters share common options to determine their scope:
+
+@table @option
+@item a/autoq
+Honor the quality commands for this subfilter.
+
+@item c/chrom
+Do chrominance filtering, too (default).
+
+@item y/nochrom
+Do luminance filtering only (no chrominance).
+
+@item n/noluma
+Do chrominance filtering only (no luminance).
+@end table
+
+These options can be appended after the subfilter name, separated by a '|'.
+
+Available subfilters are:
+
+@table @option
+@item hb/hdeblock[|difference[|flatness]]
+Horizontal deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item vb/vdeblock[|difference[|flatness]]
+Vertical deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item ha/hadeblock[|difference[|flatness]]
+Accurate horizontal deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item va/vadeblock[|difference[|flatness]]
+Accurate vertical deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+@end table
+
+The horizontal and vertical deblocking filters share the difference and
+flatness values so you cannot set different horizontal and vertical
+thresholds.
+
+@table @option
+@item h1/x1hdeblock
+Experimental horizontal deblocking filter
+
+@item v1/x1vdeblock
+Experimental vertical deblocking filter
+
+@item dr/dering
+Deringing filter
+
+@item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
+@table @option
+@item threshold1
+larger -> stronger filtering
+@item threshold2
+larger -> stronger filtering
+@item threshold3
+larger -> stronger filtering
+@end table
+
+@item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
+@table @option
+@item f/fullyrange
+Stretch luminance to @code{0-255}.
+@end table
+
+@item lb/linblenddeint
+Linear blend deinterlacing filter that deinterlaces the given block by
+filtering all lines with a @code{(1 2 1)} filter.
+
+@item li/linipoldeint
+Linear interpolating deinterlacing filter that deinterlaces the given block by
+linearly interpolating every second line.
+
+@item ci/cubicipoldeint
+Cubic interpolating deinterlacing filter deinterlaces the given block by
+cubically interpolating every second line.
+
+@item md/mediandeint
+Median deinterlacing filter that deinterlaces the given block by applying a
+median filter to every second line.
+
+@item fd/ffmpegdeint
+FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
+second line with a @code{(-1 4 2 4 -1)} filter.
+
+@item l5/lowpass5
+Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
+block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
+
+@item fq/forceQuant[|quantizer]
+Overrides the quantizer table from the input with the constant quantizer you
+specify.
+@table @option
+@item quantizer
+Quantizer to use
+@end table
+
+@item de/default
+Default pp filter combination (@code{hb|a,vb|a,dr|a})
+
+@item fa/fast
+Fast pp filter combination (@code{h1|a,v1|a,dr|a})
+
+@item ac
+High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply horizontal and vertical deblocking, deringing and automatic
+brightness/contrast:
+@example
+pp=hb/vb/dr/al
+@end example
+
+@item
+Apply default filters without brightness/contrast correction:
+@example
+pp=de/-al
+@end example
+
+@item
+Apply default filters and temporal denoiser:
+@example
+pp=default/tmpnoise|1|2|3
+@end example
+
+@item
+Apply deblocking on luminance only, and switch vertical deblocking on or off
+automatically depending on available CPU time:
+@example
+pp=hb|y/vb|a
+@end example
+@end itemize
+
+@section psnr
+
+Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
+Ratio) between two input videos.
+
+This filter takes in input two input videos, the first input is
+considered the "main" source and is passed unchanged to the
+output. The second input is used as a "reference" video for computing
+the PSNR.
+
+Both video inputs must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+The obtained average PSNR is printed through the logging system.
+
+The filter stores the accumulated MSE (mean squared error) of each
+frame, and at the end of the processing it is averaged across all frames
+equally, and the following formula is applied to obtain the PSNR:
+
+@example
+PSNR = 10*log10(MAX^2/MSE)
+@end example
+
+Where MAX is the average of the maximum values of each component of the
+image.
+
+The description of the accepted parameters follows.
+
+@table @option
+@item stats_file, f
+If specified the filter will use the named file to save the PSNR of
+each individual frame.
+@end table
+
+The file printed if @var{stats_file} is selected, contains a sequence of
+key/value pairs of the form @var{key}:@var{value} for each compared
+couple of frames.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 1
+
+@item mse_avg
+Mean Square Error pixel-by-pixel average difference of the compared
+frames, averaged over all the image components.
+
+@item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
+Mean Square Error pixel-by-pixel average difference of the compared
+frames for the component specified by the suffix.
+
+@item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
+Peak Signal to Noise ratio of the compared frames for the component
+specified by the suffix.
+@end table
+
+For example:
+@example
+movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
+[main][ref] psnr="stats_file=stats.log" [out]
+@end example
+
+On this example the input file being processed is compared with the
+reference file @file{ref_movie.mpg}. The PSNR of each individual frame
+is stored in @file{stats.log}.
+
+@section pullup
+
+Pulldown reversal (inverse telecine) filter, capable of handling mixed
+hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
+content.
+
+The pullup filter is designed to take advantage of future context in making
+its decisions. This filter is stateless in the sense that it does not lock
+onto a pattern to follow, but it instead looks forward to the following
+fields in order to identify matches and rebuild progressive frames.
+
+To produce content with an even framerate, insert the fps filter after
+pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
+@code{fps=24} for 30fps and the (rare) telecined 25fps input.
+
+The filter accepts the following options:
+
+@table @option
+@item jl
+@item jr
+@item jt
+@item jb
+These options set the amount of "junk" to ignore at the left, right, top, and
+bottom of the image, respectively. Left and right are in units of 8 pixels,
+while top and bottom are in units of 2 lines.
+The default is 8 pixels on each side.
+
+@item sb
+Set the strict breaks. Setting this option to 1 will reduce the chances of
+filter generating an occasional mismatched frame, but it may also cause an
+excessive number of frames to be dropped during high motion sequences.
+Conversely, setting it to -1 will make filter match fields more easily.
+This may help processing of video where there is slight blurring between
+the fields, but may also cause there to be interlaced frames in the output.
+Default value is @code{0}.
+
+@item mp
+Set the metric plane to use. It accepts the following values:
+@table @samp
+@item l
+Use luma plane.
+
+@item u
+Use chroma blue plane.
+
+@item v
+Use chroma red plane.
+@end table
+
+This option may be set to use chroma plane instead of the default luma plane
+for doing filter's computations. This may improve accuracy on very clean
+source material, but more likely will decrease accuracy, especially if there
+is chroma noise (rainbow effect) or any grayscale video.
+The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
+load and make pullup usable in realtime on slow machines.
+@end table
+
+For example to inverse telecined NTSC input:
+@example
+pullup,fps=24000/1001
+@end example
+
+@section removelogo
+
+Suppress a TV station logo, using an image file to determine which
+pixels comprise the logo. It works by filling in the pixels that
+comprise the logo with neighboring pixels.
+
+The filter accepts the following options:
+
+@table @option
+@item filename, f
+Set the filter bitmap file, which can be any image format supported by
+libavformat. The width and height of the image file must match those of the
+video stream being processed.
+@end table
+
+Pixels in the provided bitmap image with a value of zero are not
+considered part of the logo, non-zero pixels are considered part of
+the logo. If you use white (255) for the logo and black (0) for the
+rest, you will be safe. For making the filter bitmap, it is
+recommended to take a screen capture of a black frame with the logo
+visible, and then using a threshold filter followed by the erode
+filter once or twice.
+
+If needed, little splotches can be fixed manually. Remember that if
+logo pixels are not covered, the filter quality will be much
+reduced. Marking too many pixels as part of the logo does not hurt as
+much, but it will increase the amount of blurring needed to cover over
+the image and will destroy more information than necessary, and extra
+pixels will slow things down on a large logo.
+
+@section rotate
+
+Rotate video by an arbitrary angle expressed in radians.
+
+The filter accepts the following options:
+
+A description of the optional parameters follows.
+@table @option
+@item angle, a
+Set an expression for the angle by which to rotate the input video
+clockwise, expressed as a number of radians. A negative value will
+result in a counter-clockwise rotation. By default it is set to "0".
+
+This expression is evaluated for each frame.
+
+@item out_w, ow
+Set the output width expression, default value is "iw".
+This expression is evaluated just once during configuration.
+
+@item out_h, oh
+Set the output height expression, default value is "ih".
+This expression is evaluated just once during configuration.
+
+@item bilinear
+Enable bilinear interpolation if set to 1, a value of 0 disables
+it. Default value is 1.
+
+@item fillcolor, c
+Set the color used to fill the output area not covered by the rotated
+image. For the generalsyntax of this option, check the "Color" section in the
+ffmpeg-utils manual. If the special value "none" is selected then no
+background is printed (useful for example if the background is never shown).
+
+Default value is "black".
+@end table
+
+The expressions for the angle and the output size can contain the
+following constants and functions:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 0. It is always NAN
+before the first frame is filtered.
+
+@item t
+time in seconds of the input frame, it is set to 0 when the filter is
+configured. It is always NAN before the first frame is filtered.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item in_w, iw
+@item in_h, ih
+the input video width and heigth
+
+@item out_w, ow
+@item out_h, oh
+the output width and heigth, that is the size of the padded area as
+specified by the @var{width} and @var{height} expressions
+
+@item rotw(a)
+@item roth(a)
+the minimal width/height required for completely containing the input
+video rotated by @var{a} radians.
+
+These are only available when computing the @option{out_w} and
+@option{out_h} expressions.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Rotate the input by PI/6 radians clockwise:
+@example
+rotate=PI/6
+@end example
+
+@item
+Rotate the input by PI/6 radians counter-clockwise:
+@example
+rotate=-PI/6
+@end example
+
+@item
+Apply a constant rotation with period T, starting from an angle of PI/3:
+@example
+rotate=PI/3+2*PI*t/T
+@end example
+
+@item
+Make the input video rotation oscillating with a period of T
+seconds and an amplitude of A radians:
+@example
+rotate=A*sin(2*PI/T*t)
+@end example
+
+@item
+Rotate the video, output size is choosen so that the whole rotating
+input video is always completely contained in the output:
+@example
+rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
+@end example
+
+@item
+Rotate the video, reduce the output size so that no background is ever
+shown:
+@example
+rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
+@end example
+@end itemize
+
+@subsection Commands
+
+The filter supports the following commands:
+
+@table @option
+@item a, angle
+Set the angle expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
+
+@section sab
+
+Apply Shape Adaptive Blur.
+
+The filter accepts the following options:
+
+@table @option
+@item luma_radius, lr
+Set luma blur filter strength, must be a value in range 0.1-4.0, default
+value is 1.0. A greater value will result in a more blurred image, and
+in slower processing.
+
+@item luma_pre_filter_radius, lpfr
+Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
+value is 1.0.
+
+@item luma_strength, ls
+Set luma maximum difference between pixels to still be considered, must
+be a value in the 0.1-100.0 range, default value is 1.0.
+
+@item chroma_radius, cr
+Set chroma blur filter strength, must be a value in range 0.1-4.0. A
+greater value will result in a more blurred image, and in slower
+processing.
+
+@item chroma_pre_filter_radius, cpfr
+Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
+
+@item chroma_strength, cs
+Set chroma maximum difference between pixels to still be considered,
+must be a value in the 0.1-100.0 range.
+@end table
+
+Each chroma option value, if not explicitly specified, is set to the
+corresponding luma option value.
+
+@section scale
+
+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.
+
+If the input image format is different from the format requested by
+the next filter, the scale filter will convert the input to the
+requested format.
+
+@subsection Options
+The filter accepts the following options, or any of the options
+supported by the libswscale scaler.
+
+See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
+the complete list of scaler options.
+
+@table @option
+@item width, w
+@item height, h
+Set the output video dimension expression. Default value is the input
+dimension.
+
+If the value is 0, the input width is used for the output.
+
+If one of the values is -1, the scale filter will use a value that
+maintains the aspect ratio of the input image, calculated from the
+other specified dimension. If both of them are -1, the input size is
+used
+
+See below for the list of accepted constants for use in the dimension
+expression.
+
+@item interl
+Set the interlacing mode. It accepts the following values:
+
+@table @samp
+@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 @samp{0}.
+
+@item flags
+Set libswscale scaling flags. See
+@ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
+complete list of values. If not explictly specified the filter applies
+the default flags.
+
+@item size, s
+Set the video size. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual.
+
+@item in_color_matrix
+@item out_color_matrix
+Set in/output YCbCr color space type.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder.
+
+If not specified, the color space type depends on the pixel format.
+
+Possible values:
+
+@table @samp
+@item auto
+Choose automatically.
+
+@item bt709
+Format conforming to International Telecommunication Union (ITU)
+Recommendation BT.709.
+
+@item fcc
+Set color space conforming to the United States Federal Communications
+Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
+
+@item bt601
+Set color space conforming to:
+
+@itemize
+@item
+ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
+
+@item
+ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
+
+@item
+Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
+
+@end itemize
+
+@item smpte240m
+Set color space conforming to SMPTE ST 240:1999.
+@end table
+
+@item in_range
+@item out_range
+Set in/output YCbCr sample range.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder. If not specified, the
+range depends on the pixel format. Possible values:
+
+@table @samp
+@item auto
+Choose automatically.
+
+@item jpeg/full/pc
+Set full range (0-255 in case of 8-bit luma).
+
+@item mpeg/tv
+Set "MPEG" range (16-235 in case of 8-bit luma).
+@end table
+
+@item force_original_aspect_ratio
+Enable decreasing or increasing output video width or height if necessary to
+keep the original aspect ratio. Possible values:
+
+@table @samp
+@item disable
+Scale the video as specified and disable this feature.
+
+@item decrease
+The output video dimensions will automatically be decreased if needed.
+
+@item increase
+The output video dimensions will automatically be increased if needed.
+
+@end table
+
+One useful instance of this option is that when you know a specific device's
+maximum allowed resolution, you can use this to limit the output video to
+that, while retaining the aspect ratio. For example, device A allows
+1280x720 playback, and your video is 1920x800. Using this option (set it to
+decrease) and specifying 1280x720 to the command line makes the output
+1280x533.
+
+Please note that this is a different thing than specifying -1 for @option{w}
+or @option{h}, you still need to specify the output resolution for this option
+to work.
+
+@end table
+
+The values of the @option{w} and @option{h} options are expressions
+containing the following constants:
+
+@table @var
+@item in_w
+@item in_h
+the input width and height
+
+@item iw
+@item ih
+same as @var{in_w} and @var{in_h}
+
+@item out_w
+@item out_h
+the output (scaled) width and height
+
+@item ow
+@item oh
+same as @var{out_w} and @var{out_h}
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Scale the input video to a size of 200x100:
+@example
+scale=w=200:h=100
+@end example
+
+This is equivalent to:
+@example
+scale=200:100
+@end example
+
+or:
+@example
+scale=200x100
+@end example
+
+@item
+Specify a size abbreviation for the output size:
+@example
+scale=qcif
+@end example
+
+which can also be written as:
+@example
+scale=size=qcif
+@end example
+
+@item
+Scale the input to 2x:
+@example
+scale=w=2*iw:h=2*ih
+@end example
+
+@item
+The above is the same as:
+@example
+scale=2*in_w:2*in_h
+@end example
+
+@item
+Scale the input to 2x with forced interlaced scaling:
+@example
+scale=2*iw:2*ih:interl=1
+@end example
+
+@item
+Scale the input to half size:
+@example
+scale=w=iw/2:h=ih/2
+@end example
+
+@item
+Increase the width, and set the height to the same size:
+@example
+scale=3/2*iw:ow
+@end example
+
+@item
+Seek for Greek harmony:
+@example
+scale=iw:1/PHI*iw
+scale=ih*PHI:ih
+@end example
+
+@item
+Increase the height, and set the width to 3/2 of the height:
+@example
+scale=w=3/2*oh:h=3/5*ih
+@end example
+
+@item
+Increase the size, but make the size a multiple of the chroma
+subsample values:
+@example
+scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
+@end example
+
+@item
+Increase the width to a maximum of 500 pixels, keep the same input
+aspect ratio:
+@example
+scale=w='min(500\, iw*3/2):h=-1'
+@end example
+@end itemize
+
+@section separatefields
+
+The @code{separatefields} takes a frame-based video input and splits
+each frame into its components fields, producing a new half height clip
+with twice the frame rate and twice the frame count.
+
+This filter use field-dominance information in frame to decide which
+of each pair of fields to place first in the output.
+If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
+
+@section setdar, setsar
+
+The @code{setdar} filter sets the Display Aspect Ratio for the filter
+output video.
+
+This is done by changing the specified Sample (aka Pixel) Aspect
+Ratio, according to the following equation:
+@example
+@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
+@end example
+
+Keep in mind that the @code{setdar} filter does not modify the pixel
+dimensions of the video frame. Also the display aspect ratio set by
+this filter may be changed by later filters in the filterchain,
+e.g. in case of scaling or if another "setdar" or a "setsar" filter is
+applied.
+
+The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
+the filter output video.
+
+Note that as a consequence of the application of this filter, the
+output display aspect ratio will change according to the equation
+above.
+
+Keep in mind that the sample aspect ratio set by the @code{setsar}
+filter may be changed by later filters in the filterchain, e.g. if
+another "setsar" or a "setdar" filter is applied.
+
+The filters accept the following options:
+
+@table @option
+@item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
+Set the aspect ratio used by the filter.
+
+The parameter can be a floating point number string, an expression, or
+a string of the form @var{num}:@var{den}, where @var{num} and
+@var{den} are the numerator and denominator of the aspect ratio. If
+the parameter is not specified, it is assumed the value "0".
+In case the form "@var{num}:@var{den}" is used, the @code{:} character
+should be escaped.
+
+@item max
+Set the maximum integer value to use for expressing numerator and
+denominator when reducing the expressed aspect ratio to a rational.
+Default value is @code{100}.
+
+@end table
+
++The parameter @var{sar} is an expression containing
++the following constants:
++
++@table @option
++@item E, PI, PHI
++the corresponding mathematical approximated values for e
++(euler number), pi (greek PI), phi (golden ratio)
++
++@item w, h
++the input width and height
++
++@item a
++same as @var{w} / @var{h}
++
++@item sar
++input sample aspect ratio
++
++@item dar
++input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
++
++@item hsub, vsub
++horizontal and vertical chroma subsample values. For example for the
++pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
++@end table
++
+@subsection Examples
+
+@itemize
+
+@item
+To change the display aspect ratio to 16:9, specify one of the following:
+@example
+setdar=dar=1.77777
+setdar=dar=16/9
+setdar=dar=1.77777
+@end example
+
+@item
+To change the sample aspect ratio to 10:11, specify:
+@example
+setsar=sar=10/11
+@end example
+
+@item
+To set a display aspect ratio of 16:9, and specify a maximum integer value of
+1000 in the aspect ratio reduction, use the command:
+@example
+setdar=ratio=16/9:max=1000
+@end example
+
+@end itemize
+
+@anchor{setfield}
+@section setfield
+
+Force field for the output video frame.
+
+The @code{setfield} filter marks the interlace type field for the
+output frames. It does not change the input frame, but only sets the
+corresponding property, which affects how the frame is treated by
+following filters (e.g. @code{fieldorder} or @code{yadif}).
+
+The filter accepts the following options:
+
+@table @option
+
+@item mode
+Available values are:
+
+@table @samp
+@item auto
+Keep the same field property.
+
+@item bff
+Mark the frame as bottom-field-first.
+
+@item tff
+Mark the frame as top-field-first.
+
+@item prog
+Mark the frame as progressive.
+@end table
+@end table
+
+@section showinfo
+
+Show a line containing various information for each input video frame.
+The input video is not modified.
+
+The shown line contains a sequence of key/value pairs of the form
+@var{key}:@var{value}.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+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.
+
+@item pts_time
+Presentation TimeStamp of the input frame, expressed as a number of
+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 video)
+
+@item fmt
+pixel format name
+
+@item sar
+sample aspect ratio of the input frame, expressed in the form
+@var{num}/@var{den}
+
+@item s
+size of the input frame. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual.
+
+@item i
+interlaced mode ("P" for "progressive", "T" for top field first, "B"
+for bottom field first)
+
+@item iskey
+1 if the frame is a key frame, 0 otherwise
+
+@item type
+picture type of the input frame ("I" for an I-frame, "P" for a
+P-frame, "B" for a B-frame, "?" for unknown type).
+Check also the documentation of the @code{AVPictureType} enum and of
+the @code{av_get_picture_type_char} function defined in
+@file{libavutil/avutil.h}.
+
+@item checksum
+Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
+
+@item plane_checksum
+Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
+expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
+@end table
+
+@anchor{smartblur}
+@section smartblur
+
+Blur the input video without impacting the outlines.
+
+The filter accepts the following options:
+
+@table @option
+@item luma_radius, lr
+Set the luma radius. The option value must be a float number in
+the range [0.1,5.0] that specifies the variance of the gaussian filter
+used to blur the image (slower if larger). Default value is 1.0.
+
+@item luma_strength, ls
+Set the luma strength. The option value must be a float number
+in the range [-1.0,1.0] that configures the blurring. A value included
+in [0.0,1.0] will blur the image whereas a value included in
+[-1.0,0.0] will sharpen the image. Default value is 1.0.
+
+@item luma_threshold, lt
+Set the luma threshold used as a coefficient to determine
+whether a pixel should be blurred or not. The option value must be an
+integer in the range [-30,30]. A value of 0 will filter all the image,
+a value included in [0,30] will filter flat areas and a value included
+in [-30,0] will filter edges. Default value is 0.
+
+@item chroma_radius, cr
+Set the chroma radius. The option value must be a float number in
+the range [0.1,5.0] that specifies the variance of the gaussian filter
+used to blur the image (slower if larger). Default value is 1.0.
+
+@item chroma_strength, cs
+Set the chroma strength. The option value must be a float number
+in the range [-1.0,1.0] that configures the blurring. A value included
+in [0.0,1.0] will blur the image whereas a value included in
+[-1.0,0.0] will sharpen the image. Default value is 1.0.
+
+@item chroma_threshold, ct
+Set the chroma threshold used as a coefficient to determine
+whether a pixel should be blurred or not. The option value must be an
+integer in the range [-30,30]. A value of 0 will filter all the image,
+a value included in [0,30] will filter flat areas and a value included
+in [-30,0] will filter edges. Default value is 0.
+@end table
+
+If a chroma option is not explicitly set, the corresponding luma value
+is set.
+
+@section stereo3d
+
+Convert between different stereoscopic image formats.
+
+The filters accept the following options:
+
+@table @option
+@item in
+Set stereoscopic image format of input.
+
+Available values for input image formats are:
+@table @samp
+@item sbsl
+side by side parallel (left eye left, right eye right)
+
+@item sbsr
+side by side crosseye (right eye left, left eye right)
+
+@item sbs2l
+side by side parallel with half width resolution
+(left eye left, right eye right)
+
+@item sbs2r
+side by side crosseye with half width resolution
+(right eye left, left eye right)
+
+@item abl
+above-below (left eye above, right eye below)
+
+@item abr
+above-below (right eye above, left eye below)
+
+@item ab2l
+above-below with half height resolution
+(left eye above, right eye below)
+
+@item ab2r
+above-below with half height resolution
+(right eye above, left eye below)
+
+@item al
+alternating frames (left eye first, right eye second)
+
+@item ar
+alternating frames (right eye first, left eye second)
+
+Default value is @samp{sbsl}.
+@end table
+
+@item out
+Set stereoscopic image format of output.
+
+Available values for output image formats are all the input formats as well as:
+@table @samp
+@item arbg
+anaglyph red/blue gray
+(red filter on left eye, blue filter on right eye)
+
+@item argg
+anaglyph red/green gray
+(red filter on left eye, green filter on right eye)
+
+@item arcg
+anaglyph red/cyan gray
+(red filter on left eye, cyan filter on right eye)
+
+@item arch
+anaglyph red/cyan half colored
+(red filter on left eye, cyan filter on right eye)
+
+@item arcc
+anaglyph red/cyan color
+(red filter on left eye, cyan filter on right eye)
+
+@item arcd
+anaglyph red/cyan color optimized with the least squares projection of dubois
+(red filter on left eye, cyan filter on right eye)
+
+@item agmg
+anaglyph green/magenta gray
+(green filter on left eye, magenta filter on right eye)
+
+@item agmh
+anaglyph green/magenta half colored
+(green filter on left eye, magenta filter on right eye)
+
+@item agmc
+anaglyph green/magenta colored
+(green filter on left eye, magenta filter on right eye)
+
+@item agmd
+anaglyph green/magenta color optimized with the least squares projection of dubois
+(green filter on left eye, magenta filter on right eye)
+
+@item aybg
+anaglyph yellow/blue gray
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybh
+anaglyph yellow/blue half colored
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybc
+anaglyph yellow/blue colored
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybd
+anaglyph yellow/blue color optimized with the least squares projection of dubois
+(yellow filter on left eye, blue filter on right eye)
+
+@item irl
+interleaved rows (left eye has top row, right eye starts on next row)
+
+@item irr
+interleaved rows (right eye has top row, left eye starts on next row)
+
+@item ml
+mono output (left eye only)
+
+@item mr
+mono output (right eye only)
+@end table
+
+Default value is @samp{arcd}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Convert input video from side by side parallel to anaglyph yellow/blue dubois:
+@example
+stereo3d=sbsl:aybd
+@end example
+
+@item
+Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
+@example
+stereo3d=abl:sbsr
+@end example
+@end itemize
+
+@section spp
+
+Apply a simple postprocessing filter that compresses and decompresses the image
+at several (or - in the case of @option{quality} level @code{6} - all) shifts
+and average the results.
+
+The filter accepts the following options:
+
+@table @option
+@item quality
+Set quality. This option defines the number of levels for averaging. It accepts
+an integer in the range 0-6. If set to @code{0}, the filter will have no
+effect. A value of @code{6} means the higher quality. For each increment of
+that value the speed drops by a factor of approximately 2. Default value is
+@code{3}.
+
+@item qp
+Force a constant quantization parameter. If not set, the filter will use the QP
+from the video stream (if available).
+
+@item mode
+Set thresholding mode. Available modes are:
+
+@table @samp
+@item hard
+Set hard thresholding (default).
+@item soft
+Set soft thresholding (better de-ringing effect, but likely blurrier).
+@end table
+
+@item use_bframe_qp
+Enable the use of the QP from the B-Frames if set to @code{1}. Using this
+option may cause flicker since the B-Frames have often larger QP. Default is
+@code{0} (not enabled).
+@end table
+
+@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.
+
+The filter accepts the following options:
+
+@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. For the syntax of this option, check the "Video size" section in
+the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
+this is necessary to correctly scale the fonts if the aspect ratio has been
+changed.
+
+@item charenc
+Set subtitles input character encoding. @code{subtitles} filter only. Only
+useful if not UTF-8.
+@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 super2xsai
+
+Scale the input by 2x and smooth using the Super2xSaI (Scale and
+Interpolate) pixel art scaling algorithm.
+
+Useful for enlarging pixel art images without reducing sharpness.
+
+@section swapuv
+Swap U & V plane.
+
+@section telecine
+
+Apply telecine process to the video.
+
+This filter accepts the following options:
+
+@table @option
+@item first_field
+@table @samp
+@item top, t
+top field first
+@item bottom, b
+bottom field first
+The default value is @code{top}.
+@end table
+
+@item pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is @code{23}.
+@end table
+
+@example
+Some typical patterns:
+
+NTSC output (30i):
+27.5p: 32222
+24p: 23 (classic)
+24p: 2332 (preferred)
+20p: 33
+18p: 334
+16p: 3444
+
+PAL output (25i):
+27.5p: 12222
+24p: 222222222223 ("Euro pulldown")
+16.67p: 33
+16p: 33333334
+@end example
+
+@section thumbnail
+Select the most representative frame in a given sequence of consecutive frames.
+
+The filter accepts the following options:
+
+@table @option
+@item n
+Set the frames batch size to analyze; in a set of @var{n} frames, the filter
+will pick one of them, and then handle the next batch of @var{n} frames until
+the end. Default is @code{100}.
+@end table
+
+Since the filter keeps track of the whole frames sequence, a bigger @var{n}
+value will result in a higher memory usage, so a high value is not recommended.
+
+@subsection Examples
+
+@itemize
+@item
+Extract one picture each 50 frames:
+@example
+thumbnail=50
+@end example
+
+@item
+Complete example of a thumbnail creation with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
+@end example
+@end itemize
+
+@section tile
+
+Tile several successive frames together.
+
+The filter accepts the following options:
+
+@table @option
+
+@item layout
+Set the grid size (i.e. the number of lines and columns). For the syntax of
+this option, check the "Video size" section in the ffmpeg-utils manual.
+
+@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.
+
+@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 color
+Specify the color of the unused areaFor the syntax of this option, check the
+"Color" section in the ffmpeg-utils manual. The default value of @var{color}
+is "black".
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
+@example
+ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
+@end example
+The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
+duplicating each output frame to accomodate the originally detected frame
+rate.
+
+@item
+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
+@end itemize
+
+@section tinterlace
+
+Perform various types of temporal field interlacing.
+
+Frames are counted starting from 1, so the first input frame is
+considered odd.
+
+The filter accepts the following options:
+
+@table @option
+
+@item mode
+Specify the mode of the interlacing. This option can also be specified
+as a value alone. See below for a list of values for this option.
+
+Available values are:
+
+@table @samp
+@item merge, 0
+Move odd frames into the upper field, even into the lower field,
+generating a double height frame at half frame rate.
+
+@item drop_odd, 1
+Only output even frames, odd frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+@item drop_even, 2
+Only output odd frames, even frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+@item pad, 3
+Expand each frame to full height, but pad alternate lines with black,
+generating a frame with double height at the same input frame rate.
+
+@item interleave_top, 4
+Interleave the upper field from odd frames with the lower field from
+even frames, generating a frame with unchanged height at half frame rate.
+
+@item interleave_bottom, 5
+Interleave the lower field from odd frames with the upper field from
+even frames, generating a frame with unchanged height at half frame rate.
+
+@item interlacex2, 6
+Double frame rate with unchanged height. Frames are inserted each
+containing the second temporal field from the previous input frame and
+the first temporal field from the next input frame. This mode relies on
+the top_field_first flag. Useful for interlaced video displays with no
+field synchronisation.
+@end table
+
+Numeric values are deprecated but are accepted for backward
+compatibility reasons.
+
+Default mode is @code{merge}.
+
+@item flags
+Specify flags influencing the filter process.
+
+Available value for @var{flags} is:
+
+@table @option
+@item low_pass_filter, vlfp
+Enable vertical low-pass filtering in the filter.
+Vertical low-pass filtering is required when creating an interlaced
+destination from a progressive source which contains high-frequency
+vertical detail. Filtering will reduce interlace 'twitter' and Moire
+patterning.
+
+Vertical low-pass filtering can only be enabled for @option{mode}
+@var{interleave_top} and @var{interleave_bottom}.
+
+@end table
+@end table
+
+@section transpose
+
+Transpose rows with columns in the input video and optionally flip it.
+
+This filter accepts the following options:
+
+@table @option
+
+@item dir
+Specify the transposition direction.
+
+Can assume the following values:
+@table @samp
+@item 0, 4, cclock_flip
+Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
+@example
+L.R L.l
+. . -> . .
+l.r R.r
+@end example
+
+@item 1, 5, clock
+Rotate by 90 degrees clockwise, that is:
+@example
+L.R l.L
+. . -> . .
+l.r r.R
+@end example
+
+@item 2, 6, cclock
+Rotate by 90 degrees counterclockwise, that is:
+@example
+L.R R.r
+. . -> . .
+l.r L.l
+@end example
+
+@item 3, 7, clock_flip
+Rotate by 90 degrees clockwise and vertically flip, that is:
+@example
+L.R r.R
+. . -> . .
+l.r l.L
+@end example
+@end table
+
+For values between 4-7, the transposition is only done if the input
+video geometry is portrait and not landscape. These values are
+deprecated, the @code{passthrough} option should be used instead.
+
+Numerical values are deprecated, and should be dropped in favor of
+symbolic constants.
+
+@item passthrough
+Do not apply the transposition if the input geometry matches the one
+specified by the specified value. It accepts the following values:
+@table @samp
+@item none
+Always apply transposition.
+@item portrait
+Preserve portrait geometry (when @var{height} >= @var{width}).
+@item landscape
+Preserve landscape geometry (when @var{width} >= @var{height}).
+@end table
+
+Default value is @code{none}.
+@end table
+
+For example to rotate by 90 degrees clockwise and preserve portrait
+layout:
+@example
+transpose=dir=1:passthrough=portrait
+@end example
+
+The command above can also be specified as:
+@example
+transpose=1:portrait
+@end example
+
+@section trim
+Trim the input so that the output contains one continuous subpart of the input.
+
+This filter accepts the following options:
+@table @option
+@item start
+Specify time of the start of the kept section, i.e. the frame with the
+timestamp @var{start} will be the first frame in the output.
+
+@item end
+Specify time of the first frame that will be dropped, i.e. the frame
+immediately preceding the one with the timestamp @var{end} will be the last
+frame in the output.
+
+@item start_pts
+Same as @var{start}, except this option sets the start timestamp in timebase
+units instead of seconds.
+
+@item end_pts
+Same as @var{end}, except this option sets the end timestamp in timebase units
+instead of seconds.
+
+@item duration
+Specify maximum duration of the output.
+
+@item start_frame
+Number of the first frame that should be passed to output.
+
+@item end_frame
+Number of the first frame that should be dropped.
+@end table
+
+@option{start}, @option{end}, @option{duration} are expressed as time
+duration specifications, check the "Time duration" section in the
+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 _frame variants simply count the
+frames that pass through the filter. Also note that this filter does not modify
+the timestamps. If you wish that the output timestamps start at zero, insert a
+setpts filter after the trim filter.
+
+If multiple start or end options are set, this filter tries to be greedy and
+keep all the frames that match at least one of the specified constraints. To keep
+only the part that matches all the constraints at once, chain multiple trim
+filters.
+
+The defaults are such that all the input is kept. So it is possible to set e.g.
+just the end values to keep everything before the specified time.
+
+Examples:
+@itemize
+@item
+drop everything except the second minute of input
+@example
+ffmpeg -i INPUT -vf trim=60:120
+@end example
+
+@item
+keep only the first second
+@example
+ffmpeg -i INPUT -vf trim=duration=1
+@end example
+
+@end itemize
+
+
+@section unsharp
+
+Sharpen or blur the input video.
+
+It accepts the following parameters:
+
+@table @option
+@item luma_msize_x, lx
+Set the luma matrix horizontal size. It must be an odd integer between
+3 and 63, default value is 5.
+
+@item luma_msize_y, ly
+Set the luma matrix vertical size. It must be an odd integer between 3
+and 63, default value is 5.
+
+@item luma_amount, la
+Set the luma effect strength. It can be a float number, reasonable
+values lay between -1.5 and 1.5.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is 1.0.
+
+@item chroma_msize_x, cx
+Set the chroma matrix horizontal size. It must be an odd integer
+between 3 and 63, default value is 5.
+
+@item chroma_msize_y, cy
+Set the chroma matrix vertical size. It must be an odd integer
+between 3 and 63, default value is 5.
+
+@item chroma_amount, ca
+Set the chroma effect strength. It can be a float number, reasonable
+values lay between -1.5 and 1.5.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is 0.0.
+
+@item opencl
+If set to 1, specify using OpenCL capabilities, only available if
+FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
+
+@end table
+
+All parameters are optional and default to the equivalent of the
+string '5:5:1.0:5:5:0.0'.
+
+@subsection Examples
+
+@itemize
+@item
+Apply strong luma sharpen effect:
+@example
+unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
+@end example
+
+@item
+Apply strong blur of both luma and chroma parameters:
+@example
+unsharp=7:7:-2:7:7:-2
+@end example
+@end itemize
+
+@anchor{vidstabdetect}
+@section vidstabdetect
+
+Analyze video stabilization/deshaking. Perform pass 1 of 2, see
+@ref{vidstabtransform} for pass 2.
+
+This filter generates a file with relative translation and rotation
+transform information about subsequent frames, which is then used by
+the @ref{vidstabtransform} filter.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libvidstab}.
+
+This filter accepts the following options:
+
+@table @option
+@item result
+Set the path to the file used to write the transforms information.
+Default value is @file{transforms.trf}.
+
+@item shakiness
+Set how shaky the video is and how quick the camera is. It accepts an
+integer in the range 1-10, a value of 1 means little shakiness, a
+value of 10 means strong shakiness. Default value is 5.
+
+@item accuracy
+Set the accuracy of the detection process. It must be a value in the
+range 1-15. A value of 1 means low accuracy, a value of 15 means high
+accuracy. Default value is 9.
+
+@item stepsize
+Set stepsize of the search process. The region around minimum is
+scanned with 1 pixel resolution. Default value is 6.
+
+@item mincontrast
+Set minimum contrast. Below this value a local measurement field is
+discarded. Must be a floating point value in the range 0-1. Default
+value is 0.3.
+
+@item tripod
+Set reference frame number for tripod mode.
+
+If enabled, the motion of the frames is compared to a reference frame
+in the filtered stream, identified by the specified number. The idea
+is to compensate all movements in a more-or-less static scene and keep
+the camera view absolutely still.
+
+If set to 0, it is disabled. The frames are counted starting from 1.
+
+@item show
+Show fields and transforms in the resulting frames. It accepts an
+integer in the range 0-2. Default value is 0, which disables any
+visualization.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Use default values:
+@example
+vidstabdetect
+@end example
+
+@item
+Analyze strongly shaky movie and put the results in file
+@file{mytransforms.trf}:
+@example
+vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
+@end example
+
+@item
+Visualize the result of internal transformations in the resulting
+video:
+@example
+vidstabdetect=show=1
+@end example
+
+@item
+Analyze a video with medium shakiness using @command{ffmpeg}:
+@example
+ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
+@end example
+@end itemize
+
+@anchor{vidstabtransform}
+@section vidstabtransform
+
+Video stabilization/deshaking: pass 2 of 2,
+see @ref{vidstabdetect} for pass 1.
+
+Read a file with transform information for each frame and
+apply/compensate them. Together with the @ref{vidstabdetect}
+filter this can be used to deshake videos. See also
+@url{http://public.hronopik.de/vid.stab}. It is important to also use
+the unsharp filter, see below.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libvidstab}.
+
+This filter accepts the following options:
+
+@table @option
+
+@item input
+path to the file used to read the transforms (default: @file{transforms.trf})
+
+@item smoothing
+number of frames (value*2 + 1) used for lowpass filtering the camera movements
+(default: 10). For example a number of 10 means that 21 frames are used
+(10 in the past and 10 in the future) to smoothen the motion in the
+video. A larger values leads to a smoother video, but limits the
+acceleration of the camera (pan/tilt movements).
+
+@item maxshift
+maximal number of pixels to translate frames (default: -1 no limit)
+
+@item maxangle
+maximal angle in radians (degree*PI/180) to rotate frames (default: -1
+no limit)
+
+@item crop
+How to deal with borders that may be visible due to movement
+compensation. Available values are:
+
+@table @samp
+@item keep
+keep image information from previous frame (default)
+@item black
+fill the border black
+@end table
+
+@item invert
+@table @samp
+@item 0
+keep transforms normal (default)
+@item 1
+invert transforms
+@end table
+
+@item relative
+consider transforms as
+@table @samp
+@item 0
+absolute
+@item 1
+relative to previous frame (default)
+@end table
+
+@item zoom
+percentage to zoom (default: 0)
+@table @samp
+@item >0
+zoom in
+@item <0
+zoom out
+@end table
+
+@item optzoom
+set optimal zooming to avoid borders
+@table @samp
+@item 0
+disabled
+@item 1
+optimal static zoom value is determined (only very strong movements will lead to visible borders) (default)
+@item 2
+optimal adaptive zoom value is determined (no borders will be visible)
+@end table
+Note that the value given at zoom is added to the one calculated
+here.
+
+@item interpol
+type of interpolation
+
+Available values are:
+@table @samp
+@item no
+no interpolation
+@item linear
+linear only horizontal
+@item bilinear
+linear in both directions (default)
+@item bicubic
+cubic in both directions (slow)
+@end table
+
+@item tripod
+virtual tripod mode means that the video is stabilized such that the
+camera stays stationary. Use also @code{tripod} option of
+@ref{vidstabdetect}.
+@table @samp
+@item 0
+off (default)
+@item 1
+virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
+@end table
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+typical call with default default values:
+ (note the unsharp filter which is always recommended)
+@example
+ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
+@end example
+
+@item
+zoom in a bit more and load transform data from a given file
+@example
+vidstabtransform=zoom=5:input="mytransforms.trf"
+@end example
+
+@item
+smoothen the video even more
+@example
+vidstabtransform=smoothing=30
+@end example
+
+@end itemize
+
+@section vflip
+
+Flip the input video vertically.
+
+For example, to vertically flip a video with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf "vflip" out.avi
+@end example
+
+@section vignette
+
+Make or reverse a natural vignetting effect.
+
+The filter accepts the following options:
+
+@table @option
+@item angle, a
+Set lens angle expression as a number of radians.
+
+The value is clipped in the @code{[0,PI/2]} range.
+
+Default value: @code{"PI/5"}
+
+@item x0
+@item y0
+Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
+by default.
+
+@item mode
+Set forward/backward mode.
+
+Available modes are:
+@table @samp
+@item forward
+The larger the distance from the central point, the darker the image becomes.
+
+@item backward
+The larger the distance from the central point, the brighter the image becomes.
+This can be used to reverse a vignette effect, though there is no automatic
+detection to extract the lens @option{angle} and other settings (yet). It can
+also be used to create a burning effect.
+@end table
+
+Default value is @samp{forward}.
+
+@item eval
+Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
+
+It accepts the following values:
+@table @samp
+@item init
+Evaluate expressions only once during the filter initialization.
+
+@item frame
+Evaluate expressions for each incoming frame. This is way slower than the
+@samp{init} mode since it requires all the scalers to be re-computed, but it
+allows advanced dynamic expressions.
+@end table
+
+Default value is @samp{init}.
+
+@item dither
+Set dithering to reduce the circular banding effects. Default is @code{1}
+(enabled).
+
+@item aspect
+Set vignette aspect. This setting allows to adjust the shape of the vignette.
+Setting this value to the SAR of the input will make a rectangular vignetting
+following the dimensions of the video.
+
+Default is @code{1/1}.
+@end table
+
+@subsection Expressions
+
+The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
+following parameters.
+
+@table @option
+@item w
+@item h
+input width and height
+
+@item n
+the number of input frame, starting from 0
+
+@item pts
+the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
+@var{TB} units, NAN if undefined
+
+@item r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+@item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+@item tb
+time base of the input video
+@end table
+
+
+@subsection Examples
+
+@itemize
+@item
+Apply simple strong vignetting effect:
+@example
+vignette=PI/4
+@end example
+
+@item
+Make a flickering vignetting:
+@example
+vignette='PI/4+random(1)*PI/50':eval=frame
+@end example
+
+@end itemize
+
+@section w3fdif
+
+Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
+Deinterlacing Filter").
+
+Based on the process described by Martin Weston for BBC R&D, and
+implemented based on the de-interlace algorithm written by Jim
+Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
+uses filter coefficients calculated by BBC R&D.
+
+There are two sets of filter coefficients, so called "simple":
+and "complex". Which set of filter coefficients is used can
+be set by passing an optional parameter:
+
+@table @option
+@item filter
+Set the interlacing filter coefficients. Accepts one of the following values:
+
+@table @samp
+@item simple
+Simple filter coefficient set.
+@item complex
+More-complex filter coefficient set.
+@end table
+Default value is @samp{complex}.
+
+@item deint
+Specify which frames to deinterlace. Accept one of the following values:
+
+@table @samp
+@item all
+Deinterlace all frames,
+@item interlaced
+Only deinterlace frames marked as interlaced.
+@end table
+
+Default value is @samp{all}.
+@end table
+
+@anchor{yadif}
+@section yadif
+
+Deinterlace the input video ("yadif" means "yet another deinterlacing
+filter").
+
+This filter accepts the following options:
+
+
+@table @option
+
+@item mode
+The interlacing mode to adopt, accepts one of the following values:
+
+@table @option
+@item 0, send_frame
+output 1 frame for each frame
+@item 1, send_field
+output 1 frame for each field
+@item 2, send_frame_nospatial
+like @code{send_frame} but skip spatial interlacing check
+@item 3, send_field_nospatial
+like @code{send_field} but skip spatial interlacing check
+@end table
+
+Default value is @code{send_frame}.
+
+@item parity
+The picture field parity assumed for the input interlaced video, accepts one of
+the following values:
+
+@table @option
+@item 0, tff
+assume top field first
+@item 1, bff
+assume bottom field first
+@item -1, auto
+enable automatic detection
+@end table
+
+Default value is @code{auto}.
+If interlacing is unknown or decoder does not export this information,
+top field first will be assumed.
+
+@item deint
+Specify which frames to deinterlace. Accept one of the following
+values:
+
+@table @option
+@item 0, all
+deinterlace all frames
+@item 1, interlaced
+only deinterlace frames marked as interlaced
+@end table
+
+Default value is @code{all}.
+@end table
+
+@c man end VIDEO FILTERS
+
+@chapter Video Sources
+@c man begin VIDEO SOURCES
+
+Below is a description of the currently available video sources.
+
+@section buffer
+
+Buffer video frames, and make them available to the filter chain.
+
+This source is mainly intended for a programmatic use, in particular
+through the interface defined in @file{libavfilter/vsrc_buffer.h}.
+
+This source accepts the following options:
+
+@table @option
+
+@item video_size
+Specify the size (width and height) of the buffered video frames. For the
+syntax of this option, check the "Video size" section in the ffmpeg-utils
+manual.
+
+@item width
+Input video width.
+
+@item height
+Input video height.
+
+@item pix_fmt
+A string representing the pixel format of the buffered video frames.
+It may be a number corresponding to a pixel format, or a pixel format
+name.
+
+@item time_base
+Specify the timebase assumed by the timestamps of the buffered frames.
+
+@item frame_rate
+Specify the frame rate expected for the video stream.
+
+@item pixel_aspect, sar
+Specify the sample aspect ratio assumed by the video frames.
+
+@item sws_param
+Specify the optional parameters to be used for the scale filter which
+is automatically inserted when an input change is detected in the
+input size or format.
+@end table
+
+For example:
+@example
+buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
+@end example
+
+will instruct the source to accept video frames with size 320x240 and
+with format "yuv410p", assuming 1/24 as the timestamps timebase and
+square pixels (1:1 sample aspect ratio).
+Since the pixel format with name "yuv410p" corresponds to the number 6
+(check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
+this example corresponds to:
+@example
+buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
+@end example
+
+Alternatively, the options can be specified as a flat string, but this
+syntax is deprecated:
+
+@var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}]
+
+@section cellauto
+
+Create a pattern generated by an elementary cellular automaton.
+
+The initial state of the cellular automaton can be defined through the
+@option{filename}, and @option{pattern} options. If such options are
+not specified an initial state is created randomly.
+
+At each new frame a new row in the video is filled with the result of
+the cellular automaton next generation. The behavior when the whole
+frame is filled is defined by the @option{scroll} option.
+
+This source accepts the following options:
+
+@table @option
+@item filename, f
+Read the initial cellular automaton state, i.e. the starting row, from
+the specified file.
+In the file, each non-whitespace character is considered an alive
+cell, a newline will terminate the row, and further characters in the
+file will be ignored.
+
+@item pattern, p
+Read the initial cellular automaton state, i.e. the starting row, from
+the specified string.
+
+Each non-whitespace character in the string is considered an alive
+cell, a newline will terminate the row, and further characters in the
+string will be ignored.
+
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
+
+@item random_fill_ratio, ratio
+Set the random fill ratio for the initial cellular automaton row. It
+is a floating point number value ranging from 0 to 1, defaults to
+1/PHI.
+
+This option is ignored when a file or a pattern is specified.
+
+@item random_seed, seed
+Set the seed for filling randomly the initial row, must be an integer
+included between 0 and UINT32_MAX. If not specified, or if explicitly
+set to -1, the filter will try to use a good random seed on a best
+effort basis.
+
+@item rule
+Set the cellular automaton rule, it is a number ranging from 0 to 255.
+Default value is 110.
+
+@item size, s
+Set the size of the output video. For the syntax of this option, check
+the "Video size" section in the ffmpeg-utils manual.
+
+If @option{filename} or @option{pattern} is specified, the size is set
+by default to the width of the specified initial state row, and the
+height is set to @var{width} * PHI.
+
+If @option{size} is set, it must contain the width of the specified
+pattern string, and the specified pattern will be centered in the
+larger row.
+
+If a filename or a pattern string is not specified, the size value
+defaults to "320x518" (used for a randomly generated initial state).
+
+@item scroll
+If set to 1, scroll the output upward when all the rows in the output
+have been already filled. If set to 0, the new generated row will be
+written over the top row just after the bottom row is filled.
+Defaults to 1.
+
+@item start_full, full
+If set to 1, completely fill the output with generated rows before
+outputting the first frame.
+This is the default behavior, for disabling set the value to 0.
+
+@item stitch
+If set to 1, stitch the left and right row edges together.
+This is the default behavior, for disabling set the value to 0.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Read the initial state from @file{pattern}, and specify an output of
+size 200x400.
+@example
+cellauto=f=pattern:s=200x400
+@end example
-@anchor{dilate}
-@subsection dilate
+@item
+Generate a random initial row with a width of 200 cells, with a fill
+ratio of 2/3:
+@example
+cellauto=ratio=2/3:s=200x200
+@end example
-Dilate an image by using a specific structuring element.
-This filter corresponds to the libopencv function @code{cvDilate}.
+@item
+Create a pattern generated by rule 18 starting by a single alive cell
+centered on an initial row with width 100:
+@example
+cellauto=p=@@:s=100x400:full=0:rule=18
+@end example
-It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
+@item
+Specify a more elaborated initial pattern:
+@example
+cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
+@end example
-@var{struct_el} represents a structuring element, and has the syntax:
-@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
+@end itemize
-@var{cols} and @var{rows} represent the number of columns and rows of
-the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
-point, and @var{shape} the shape for the structuring element, and
-can be one of the values "rect", "cross", "ellipse", "custom".
+@section mandelbrot
-If the value for @var{shape} is "custom", it must be followed by a
-string of the form "=@var{filename}". The file with name
-@var{filename} is assumed to represent a binary image, with each
-printable character corresponding to a bright pixel. When a custom
-@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
-or columns and rows of the read file are assumed instead.
+Generate a Mandelbrot set fractal, and progressively zoom towards the
+point specified with @var{start_x} and @var{start_y}.
-The default value for @var{struct_el} is "3x3+0x0/rect".
+This source accepts the following options:
-@var{nb_iterations} specifies the number of times the transform is
-applied to the image, and defaults to 1.
+@table @option
-Follow some example:
+@item end_pts
+Set the terminal pts value. Default value is 400.
+
+@item end_scale
+Set the terminal scale value.
+Must be a floating point value. Default value is 0.3.
+
+@item inner
+Set the inner coloring mode, that is the algorithm used to draw the
+Mandelbrot fractal internal region.
+
+It shall assume one of the following values:
+@table @option
+@item black
+Set black mode.
+@item convergence
+Show time until convergence.
+@item mincol
+Set color based on point closest to the origin of the iterations.
+@item period
+Set period mode.
+@end table
+
+Default value is @var{mincol}.
+
+@item bailout
+Set the bailout value. Default value is 10.0.
+
+@item maxiter
+Set the maximum of iterations performed by the rendering
+algorithm. Default value is 7189.
+
+@item outer
+Set outer coloring mode.
+It shall assume one of following values:
+@table @option
+@item iteration_count
+Set iteration cound mode.
+@item normalized_iteration_count
+set normalized iteration count mode.
+@end table
+Default value is @var{normalized_iteration_count}.
+
+@item rate, r
+Set frame rate, expressed as number of frames per second. Default
+value is "25".
+
+@item size, s
+Set frame size. For the syntax of this option, check the "Video
+size" section in the ffmpeg-utils manual. Default value is "640x480".
+
+@item start_scale
+Set the initial scale value. Default value is 3.0.
+
+@item start_x
+Set the initial x position. Must be a floating point value between
+-100 and 100. Default value is -0.743643887037158704752191506114774.
+
+@item start_y
+Set the initial y position. Must be a floating point value between
+-100 and 100. Default value is -0.131825904205311970493132056385139.
+@end table
+
+@section mptestsrc
+
+Generate various test patterns, as generated by the MPlayer test filter.
+
+The size of the generated video is fixed, and is 256x256.
+This source is useful in particular for testing encoding features.
+
+This source accepts the following options:
+
+@table @option
+
+@item rate, r
+Specify the frame rate of the sourced video, as the number of frames
+generated per second. It has to be a string in the format
+@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
+number or a valid video frame rate abbreviation. The default value is
+"25".
+
+@item duration, d
+Set the video duration of the sourced video. The accepted syntax is:
@example
-# use the default values
-ocv=dilate
+[-]HH:MM:SS[.m...]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
-# dilate using a structuring element with a 5x5 cross, iterate two times
-ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
+If not specified, or the expressed duration is negative, the video is
+supposed to be generated forever.
-# read the shape from the file diamond.shape, iterate two times
-# the file diamond.shape may contain a pattern of characters like this:
-# *
-# ***
-# *****
-# ***
-# *
-# the specified cols and rows are ignored (but not the anchor point coordinates)
-ocv=dilate:0x0+2x2/custom=diamond.shape|2
+@item test, t
+
+Set the number or the name of the test to perform. Supported tests are:
+@table @option
+@item dc_luma
+@item dc_chroma
+@item freq_luma
+@item freq_chroma
+@item amp_luma
+@item amp_chroma
+@item cbp
+@item mv
+@item ring1
+@item ring2
+@item all
+@end table
+
+Default value is "all", which will cycle through the list of all tests.
+@end table
+
+For example the following:
+@example
+testsrc=t=dc_luma
@end example
-@subsection erode
+will generate a "dc_luma" test pattern.
-Erode an image by using a specific structuring element.
-This filter corresponds to the libopencv function @code{cvErode}.
+@section frei0r_src
-The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
-with the same syntax and semantics as the @ref{dilate} filter.
+Provide a frei0r source.
-@subsection smooth
+To enable compilation of this filter you need to install the frei0r
+header and configure FFmpeg with @code{--enable-frei0r}.
-Smooth the input video.
+This source accepts the following options:
-The filter takes the following parameters:
-@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
+@table @option
-@var{type} is the type of smooth filter to apply, and can be one of
-the following values: "blur", "blur_no_scale", "median", "gaussian",
-"bilateral". The default value is "gaussian".
+@item size
+The size of the video to generate. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual.
-@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
-parameters whose meanings depend on smooth type. @var{param1} and
-@var{param2} accept integer positive values or 0, @var{param3} and
-@var{param4} accept float values.
+@item framerate
+Framerate of the generated video, may be a string of the form
+@var{num}/@var{den} or a frame rate abbreviation.
-The default value for @var{param1} is 3, the default value for the
-other parameters is 0.
+@item filter_name
+The name to the frei0r source to load. For more information regarding frei0r and
+how to set the parameters read the section @ref{frei0r} in the description of
+the video filters.
-These parameters correspond to the parameters assigned to the
-libopencv function @code{cvSmooth}.
+@item filter_params
+A '|'-separated list of parameters to pass to the frei0r source.
-@anchor{overlay}
-@section overlay
+@end table
-Overlay one video on top of another.
+For example, to generate a frei0r partik0l source with size 200x200
+and frame rate 10 which is overlayed on the overlay filter main input:
+@example
+frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
+@end example
-It takes two inputs and one output, the first input is the "main"
-video on which the second input is overlayed.
+@section life
-This filter accepts the following parameters:
+Generate a life pattern.
+
+This source is based on a generalization of John Conway's life game.
+
+The sourced input represents a life grid, each pixel represents a cell
+which can be in one of two possible states, alive or dead. Every cell
+interacts with its eight neighbours, which are the cells that are
+horizontally, vertically, or diagonally adjacent.
+
+At each interaction the grid evolves according to the adopted rule,
+which specifies the number of neighbor alive cells which will make a
+cell stay alive or born. The @option{rule} option allows to specify
+the rule to adopt.
+
+This source accepts the following options:
@table @option
+@item filename, f
+Set the file from which to read the initial grid state. In the file,
+each non-whitespace character is considered an alive cell, and newline
+is used to delimit the end of each row.
-@item x
-The horizontal position of the left edge of the overlaid video on the main video.
+If this option is not specified, the initial grid is generated
+randomly.
-@item y
-The vertical position of the top edge of the overlaid video on the main video.
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
+
+@item random_fill_ratio, ratio
+Set the random fill ratio for the initial random grid. It is a
+floating point number value ranging from 0 to 1, defaults to 1/PHI.
+It is ignored when a file is specified.
+
+@item random_seed, seed
+Set the seed for filling the initial random grid, must be an integer
+included between 0 and UINT32_MAX. If not specified, or if explicitly
+set to -1, the filter will try to use a good random seed on a best
+effort basis.
+
+@item rule
+Set the life rule.
+
+A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
+where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
+@var{NS} specifies the number of alive neighbor cells which make a
+live cell stay alive, and @var{NB} the number of alive neighbor cells
+which make a dead cell to become alive (i.e. to "born").
+"s" and "b" can be used in place of "S" and "B", respectively.
+
+Alternatively a rule can be specified by an 18-bits integer. The 9
+high order bits are used to encode the next cell state if it is alive
+for each number of neighbor alive cells, the low order bits specify
+the rule for "borning" new cells. Higher order bits encode for an
+higher number of neighbor cells.
+For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
+rule of 12 and a born rule of 9, which corresponds to "S23/B03".
+
+Default value is "S23/B3", which is the original Conway's game of life
+rule, and will keep a cell alive if it has 2 or 3 neighbor alive
+cells, and will born a new cell if there are three alive cells around
+a dead cell.
+
+@item size, s
+Set the size of the output video. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual.
+
+If @option{filename} is specified, the size is set by default to the
+same size of the input file. If @option{size} is set, it must contain
+the size specified in the input file, and the initial grid defined in
+that file is centered in the larger resulting area.
+
+If a filename is not specified, the size value defaults to "320x240"
+(used for a randomly generated initial grid).
+
+@item stitch
+If set to 1, stitch the left and right grid edges together, and the
+top and bottom edges also. Defaults to 1.
+
+@item mold
+Set cell mold speed. If set, a dead cell will go from @option{death_color} to
+@option{mold_color} with a step of @option{mold}. @option{mold} can have a
+value from 0 to 255.
+
+@item life_color
+Set the color of living (or new born) cells.
+@item death_color
+Set the color of dead cells. If @option{mold} is set, this is the first color
+used to represent a dead cell.
+
+@item mold_color
+Set mold color, for definitely dead and moldy cells.
+
+For the syntax of these 3 color options, check the "Color" section in the
+ffmpeg-utils manual.
@end table
-The parameters are expressions containing the following parameters:
+@subsection Examples
+
+@itemize
+@item
+Read a grid from @file{pattern}, and center it on a grid of size
+300x300 pixels:
+@example
+life=f=pattern:s=300x300
+@end example
+
+@item
+Generate a random grid of size 200x200, with a fill ratio of 2/3:
+@example
+life=ratio=2/3:s=200x200
+@end example
+
+@item
+Specify a custom rule for evolving a randomly generated grid:
+@example
+life=rule=S14/B34
+@end example
+
+@item
+Full example with slow death effect (mold) using @command{ffplay}:
+@example
+ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
+@end example
+@end itemize
+
+@anchor{color}
+@anchor{haldclutsrc}
+@anchor{nullsrc}
+@anchor{rgbtestsrc}
+@anchor{smptebars}
+@anchor{smptehdbars}
+@anchor{testsrc}
+@section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
+
+The @code{color} source provides an uniformly colored input.
+
+The @code{haldclutsrc} source provides an identity Hald CLUT. See also
+@ref{haldclut} filter.
+
+The @code{nullsrc} source returns unprocessed video frames. It is
+mainly useful to be employed in analysis / debugging tools, or as the
+source for filters which ignore the input data.
+
+The @code{rgbtestsrc} source generates an RGB test pattern useful for
+detecting RGB vs BGR issues. You should see a red, green and blue
+stripe from top to bottom.
+
+The @code{smptebars} source generates a color bars pattern, based on
+the SMPTE Engineering Guideline EG 1-1990.
+
+The @code{smptehdbars} source generates a color bars pattern, based on
+the SMPTE RP 219-2002.
+
+The @code{testsrc} source generates a test video pattern, showing a
+color pattern, a scrolling gradient and a timestamp. This is mainly
+intended for testing purposes.
+
+The sources accept the following options:
@table @option
-@item main_w, main_h
-main input width and height
-@item W, H
-same as @var{main_w} and @var{main_h}
+@item color, c
+Specify the color of the source, only available in the @code{color}
+source. For the syntax of this option, check the "Color" section in the
+ffmpeg-utils manual.
-@item overlay_w, overlay_h
-overlay input width and height
+@item level
+Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
+source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
+pixels to be used as identity matrix for 3D lookup tables. Each component is
+coded on a @code{1/(N*N)} scale.
-@item w, h
-same as @var{overlay_w} and @var{overlay_h}
-@end table
+@item size, s
+Specify the size of the sourced video. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual. The default value is
+"320x240".
-Be aware that frames are taken from each input video in timestamp
-order, hence, if their initial timestamps differ, it is a a good idea
-to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
-have them begin in the same zero timestamp, as it does the example for
-the @var{movie} filter.
+This option is not available with the @code{haldclutsrc} filter.
+
+@item rate, r
+Specify the frame rate of the sourced video, as the number of frames
+generated per second. It has to be a string in the format
+@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
+number or a valid video frame rate abbreviation. The default value is
+"25".
+
+@item sar
+Set the sample aspect ratio of the sourced video.
-Follow some examples:
+@item duration, d
+Set the video duration of the sourced video. The accepted syntax is:
@example
-# draw the overlay at 10 pixels from the bottom right
-# corner of the main video.
-overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
+[-]HH[:MM[:SS[.m...]]]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
+
+If not specified, or the expressed duration is negative, the video is
+supposed to be generated forever.
+
+@item decimals, n
+Set the number of decimals to show in the timestamp, only available in the
+@code{testsrc} source.
+
+The displayed timestamp value will correspond to the original
+timestamp value multiplied by the power of 10 of the specified
+value. Default value is 0.
+@end table
+
+For example the following:
+@example
+testsrc=duration=5.3:size=qcif:rate=10
+@end example
-# insert a transparent PNG logo in the bottom left corner of the input
-avconv -i input -i logo -filter_complex 'overlay=x=10:y=main_h-overlay_h-10' output
+will generate a video with a duration of 5.3 seconds, with size
+176x144 and a frame rate of 10 frames per second.
-# insert 2 different transparent PNG logos (second logo on bottom
-# right corner):
-avconv -i input -i logo1 -i logo2 -filter_complex
-'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
+The following graph description will generate a red source
+with an opacity of 0.2, with size "qcif" and a frame rate of 10
+frames per second.
+@example
+color=c=red@@0.2:s=qcif:r=10
+@end example
-# add a transparent color layer on top of the main video,
-# WxH specifies the size of the main input to the overlay filter
-color=red@.3:WxH [over]; [in][over] overlay [out]
+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{geq} filter:
+@example
+nullsrc=s=256x256, geq=random(1)*255:128:128
@end example
-You can chain together more overlays but the efficiency of such
-approach is yet to be tested.
+@subsection Commands
+
+The @code{color} source supports the following commands:
+
+@table @option
+@item c, color
+Set the color of the created image. Accepts the same syntax of the
+corresponding @option{color} option.
+@end table
+
+@c man end VIDEO SOURCES
+
+@chapter Video Sinks
+@c man begin VIDEO SINKS
+
+Below is a description of the currently available video sinks.
+
+@section buffersink
+
+Buffer video frames, and make them available to the end of the filter
+graph.
+
+This sink is mainly intended for a programmatic use, in particular
+through the interface defined in @file{libavfilter/buffersink.h}
+or the options system.
+
+It accepts a pointer to an AVBufferSinkContext structure, which
+defines the incoming buffers' formats, to be passed as the opaque
+parameter to @code{avfilter_init_filter} for initialization.
-@section pad
+@section nullsink
-Add paddings to the input image, and places the original input at the
-given coordinates @var{x}, @var{y}.
+Null video sink, do absolutely nothing with the input video. It is
+mainly useful as a template and to be employed in analysis / debugging
+tools.
-This filter accepts the following parameters:
+@c man end VIDEO SINKS
-@table @option
-@item width, height
+@chapter Multimedia Filters
+@c man begin MULTIMEDIA FILTERS
-Specify the size of the output image with the paddings added. If the
-value for @var{width} or @var{height} is 0, the corresponding input size
-is used for the output.
+Below is a description of the currently available multimedia filters.
-The @var{width} expression can reference the value set by the
-@var{height} expression, and vice versa.
+@section avectorscope
-The default value of @var{width} and @var{height} is 0.
+Convert input audio to a video output, representing the audio vector
+scope.
-@item x, y
+The filter is used to measure the difference between channels of stereo
+audio stream. A monoaural signal, consisting of identical left and right
+signal, results in straight vertical line. Any stereo separation is visible
+as a deviation from this line, creating a Lissajous figure.
+If the straight (or deviation from it) but horizontal line appears this
+indicates that the left and right channels are out of phase.
-Specify the offsets where to place the input image in the padded area
-with respect to the top/left border of the output image.
+The filter accepts the following options:
-The @var{x} expression can reference the value set by the @var{y}
-expression, and vice versa.
+@table @option
+@item mode, m
+Set the vectorscope mode.
-The default value of @var{x} and @var{y} is 0.
+Available values are:
+@table @samp
+@item lissajous
+Lissajous rotated by 45 degrees.
-@item color
+@item lissajous_xy
+Same as above but not rotated.
+@end table
-Specify the color of the padded area, it can be the name of a color
-(case insensitive match) or a 0xRRGGBB[AA] sequence.
+Default value is @samp{lissajous}.
-The default value of @var{color} is "black".
+@item size, s
+Set the video size for the output. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual. Default value is @code{400x400}.
+@item rate, r
+Set the output frame rate. Default value is @code{25}.
+
+@item rc
+@item gc
+@item bc
+Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
+Allowed range is @code{[0, 255]}.
+
+@item rf
+@item gf
+@item bf
+Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
+Allowed range is @code{[0, 255]}.
+
+@item zoom
+Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
@end table
-The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
-expressions containing the following constants:
+@subsection Examples
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), phi (golden ratio)
+@itemize
+@item
+Complete example using @command{ffplay}:
+@example
+ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
+ [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
+@end example
+@end itemize
-@item in_w, in_h
-the input video width and height
+@section concat
-@item iw, ih
-same as @var{in_w} and @var{in_h}
+Concatenate audio and video streams, joining them together one after the
+other.
-@item out_w, out_h
-the output width and height, that is the size of the padded area as
-specified by the @var{width} and @var{height} expressions
+The filter works on segments of synchronized video and audio streams. All
+segments must have the same number of streams of each type, and that will
+also be the number of streams at output.
-@item ow, oh
-same as @var{out_w} and @var{out_h}
+The filter accepts the following options:
-@item x, y
-x and y offsets as specified by the @var{x} and @var{y}
-expressions, or NAN if not yet specified
+@table @option
+
+@item n
+Set the number of segments. Default is 2.
+
+@item v
+Set the number of output video streams, that is also the number of video
+streams in each segment. Default is 1.
@item a
-input display aspect ratio, same as @var{iw} / @var{ih}
+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.
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
@end table
-Some examples follow:
+The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
+@var{a} audio outputs.
-@example
-# Add paddings with color "violet" to the input video. Output video
-# size is 640x480, the top-left corner of the input video is placed at
-# column 0, row 40.
-pad=width=640:height=480:x=0:y=40:color=violet
+There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
+segment, in the same order as the outputs, then the inputs for the second
+segment, etc.
-# pad the input to get an output with dimensions increased bt 3/2,
-# and put the input video at the center of the padded area
-pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
+Related streams do not always have exactly the same duration, for various
+reasons including codec frame size or sloppy authoring. For that reason,
+related synchronized streams (e.g. a video and its audio track) should be
+concatenated at once. The concat filter will use the duration of the longest
+stream in each segment (except the last one), and if necessary pad shorter
+audio streams with silence.
-# pad the input to get a squared output with size equal to the maximum
-# value between the input width and height, and put the input video at
-# the center of the padded area
-pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
+For this filter to work correctly, all segments must start at timestamp 0.
-# pad the input to get a final w/h ratio of 16:9
-pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
+All corresponding streams must have the same parameters in all segments; the
+filtering system will automatically select a common pixel format for video
+streams, and a common sample format, sample rate and channel layout for
+audio streams, but other settings, such as resolution, must be converted
+explicitly by the user.
-# double output size and put the input video in the bottom-right
-# corner of the output padded area
-pad="2*iw:2*ih:ow-iw:oh-ih"
-@end example
+Different frame rates are acceptable but will result in variable frame rate
+at output; be sure to configure the output file to handle it.
-@section pixdesctest
+@subsection Examples
-Pixel format descriptor test filter, mainly useful for internal
-testing. The output video should be equal to the input video.
+@itemize
+@item
+Concatenate an opening, an episode and an ending, all in bilingual version
+(video in stream 0, audio in streams 1 and 2):
+@example
+ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
+ '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
+ concat=n=3:v=1:a=2 [v] [a1] [a2]' \
+ -map '[v]' -map '[a1]' -map '[a2]' output.mkv
+@end example
-For example:
+@item
+Concatenate two parts, handling audio and video separately, using the
+(a)movie sources, and adjusting the resolution:
@example
-format=monow, pixdesctest
+movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
+movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
+[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
@end example
+Note that a desync will happen at the stitch if the audio and video streams
+do not have exactly the same duration in the first file.
-can be used to test the monowhite pixel format descriptor definition.
+@end itemize
-@section scale
+@section ebur128
-Scale the input video and/or convert the image format.
+EBU R128 scanner filter. This filter takes an audio stream as input and outputs
+it unchanged. By default, it logs a message at a frequency of 10Hz with the
+Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
+Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
-This filter accepts the following options:
+The filter also has a video output (see the @var{video} option) with a real
+time graph to observe the loudness evolution. The graphic contains the logged
+message mentioned above, so it is not printed anymore when this option is set,
+unless the verbose logging is set. The main graphing area contains the
+short-term loudness (3 seconds of analysis), and the gauge on the right is for
+the momentary loudness (400 milliseconds).
+
+More information about the Loudness Recommendation EBU R128 on
+@url{http://tech.ebu.ch/loudness}.
+
+The filter accepts the following options:
@table @option
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