@section Filtergraph syntax
A filtergraph can be represented using a textual representation, which
-is recognized by the @code{-vf} and @code{-af} options of the ff*
+is recognized by the @code{-vf} option of the ff*
tools, and by the @code{avfilter_graph_parse()} function defined in
@file{libavfilter/avfiltergraph.h}.
@table @option
+@item duration, d
+Set the minimum duration of the sourced audio. See the function
+@code{av_parse_time()} for the accepted format.
+Note that the resulting duration may be greater than the specified
+duration, as the generated audio is always cut at the end of a
+complete frame.
+
+If not specified, or the expressed duration is negative, the audio is
+supposed to be generated forever.
+
@item nb_samples, n
Set the number of samples per channel per each output frame,
default to 1024.
@item
-Generate a sin signal with frequence of 440 Hz, set sample rate to
+Generate a sin signal with frequency of 440 Hz, set sample rate to
8000 Hz:
@example
aevalsrc="sin(440*2*PI*t)::s=8000"
Below is a description of the currently available video filters.
+@section ass
+
+Draw ASS (Advanced Substation Alpha) subtitles on top of input video
+using the libass library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libass}.
+
+This filter accepts in input the name of the ass file to render.
+
+For example, to render the file @file{sub.ass} on top of the input
+video, use the command:
+@example
+ass=sub.ass
+@end example
+
@section blackframe
Detect frames that are (almost) completely black. Can be useful to
constants:
@table @option
@item w, h
-the input width and heigth in pixels
+the input width and height in pixels
@item cw, ch
the input chroma image width and height in pixels
following constants:
@table @option
-@item w, h
-the input width and heigth
+@item W, H
+the input width and height
@item tw, text_w
the width of the rendered text
@item t
timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item timecode
+initial timecode representation in "hh:mm:ss[:;.]ff" format. It can be used
+with or without text parameter. @var{rate} option must be specified
+
+@item r, rate
+frame rate (timecode only)
@end table
Some examples follow.
@section gradfun
Fix the banding artifacts that are sometimes introduced into nearly flat
-regions by truncation to 8bit colordepth.
+regions by truncation to 8bit color depth.
Interpolate the gradients that should go where the bands are, and
dither them.
Flip the input video horizontally.
-For example to horizontally flip the video in input with
-@file{ffmpeg}:
+For example to horizontally flip the input video with @command{ffmpeg}:
@example
ffmpeg -i in.avi -vf "hflip" out.avi
@end example
@table @option
@item w, h
-the input width and heigth
+the input width and height
@item val
input value for the pixel component
filter. If not specified the default values are assumed.
Refer to the official libopencv documentation for more precise
-informations:
+information:
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
Follows the list of supported libopencv filters.
@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 colums and rows of
+@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".
These parameters correspond to the parameters assigned to the
libopencv function @code{cvSmooth}.
+@anchor{overlay}
@section overlay
Overlay one video on top of another.
@table @option
@item rgb
If set to 1, force the filter to accept inputs in the RGB
-colorspace. Default value is 0.
+color space. Default value is 0.
@end table
Be aware that frames are taken from each input video in timestamp
is used for the output.
The @var{width} expression can reference the value set by the
-@var{height} expression, and viceversa.
+@var{height} expression, and vice versa.
The default value of @var{width} and @var{height} is 0.
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 viceversa.
+expression, and vice versa.
The default value of @var{x} and @var{y} is 0.
@item pos
position of the frame in the input stream, -1 if this information in
-unavailable and/or meanigless (for example in case of synthetic video)
+unavailable and/or meaningless (for example in case of synthetic video)
@item fmt
pixel format name
buffer=320:240:6:1:24:1:1
@end example
+@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 a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
+
+@table @option
+@item 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.
+
+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
+
+@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
+
+@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
+
+@item
+Specify a more elaborated initial pattern:
+@example
+cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
+@end example
+
+@end itemize
+
@section color
Provide an uniformly colored input.
Some examples follow:
@example
-# generate a frei0r partik0l source with size 200x200 and framerate 10
+# generate a frei0r partik0l source with size 200x200 and frame rate 10
# which is overlayed on the overlay filter main input
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
@end example
+@section life
+
+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 a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
+
+@table @option
+@item 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.
+
+If this option is not specified, the initial grid is generated
+randomly.
+
+@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.
+
+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.
+@end table
+
+@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
+
@section nullsrc, rgbtestsrc, testsrc
The @code{nullsrc} source returns unprocessed video frames. It is
@item size, s
Specify the size of the sourced video, it may be a string of the form
-@var{width}x@var{heigth}, or the name of a size abbreviation. The
+@var{width}x@var{height}, or the name of a size abbreviation. The
default value is "320x240".
@item rate, r
@end example
will generate a video with a duration of 5.3 seconds, with size
-176x144 and a framerate of 10 frames per second.
+176x144 and a frame rate of 10 frames per second.
If the input content is to be ignored, @code{nullsrc} can be used. The
following command generates noise in the luminance plane by employing
projects / ffmpeg / blobdiff