+@chapter Filtergraph description
+@c man begin FILTERGRAPH DESCRIPTION
+
+A filtergraph is a directed graph of connected filters. It can contain
+cycles, and there can be multiple links between a pair of
+filters. Each link has one input pad on one side connecting it to one
+filter from which it takes its input, and one output pad on the other
+side connecting it to the one filter accepting its output.
+
+Each filter in a filtergraph is an instance of a filter class
+registered in the application, which defines the features and the
+number of input and output pads of the filter.
+
+A filter with no input pads is called a "source", a filter with no
+output pads is called a "sink".
+
+@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*
+tools, and by the @code{av_parse_graph()} function defined in
+@file{libavfilter/avfiltergraph}.
+
+A filterchain consists of a sequence of connected filters, each one
+connected to the previous one in the sequence. A filterchain is
+represented by a list of ","-separated filter descriptions.
+
+A filtergraph consists of a sequence of filterchains. A sequence of
+filterchains is represented by a list of ";"-separated filterchain
+descriptions.
+
+A filter is represented by a string of the form:
+[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
+
+@var{filter_name} is the name of the filter class of which the
+described filter is an instance of, and has to be the name of one of
+the filter classes registered in the program.
+The name of the filter class is optionally followed by a string
+"=@var{arguments}".
+
+@var{arguments} is a string which contains the parameters used to
+initialize the filter instance, and are described in the filter
+descriptions below.
+
+The list of arguments can be quoted using the character "'" as initial
+and ending mark, and the character '\' for escaping the characters
+within the quoted text; otherwise the argument string is considered
+terminated when the next special character (belonging to the set
+"[]=;,") is encountered.
+
+The name and arguments of the filter are optionally preceded and
+followed by a list of link labels.
+A link label allows to name a link and associate it to a filter output
+or input pad. The preceding labels @var{in_link_1}
+... @var{in_link_N}, are associated to the filter input pads,
+the following labels @var{out_link_1} ... @var{out_link_M}, are
+associated to the output pads.
+
+When two link labels with the same name are found in the
+filtergraph, a link between the corresponding input and output pad is
+created.
+
+If an output pad is not labelled, it is linked by default to the first
+unlabelled input pad of the next filter in the filterchain.
+For example in the filterchain:
+@example
+nullsrc, split[L1], [L2]overlay, nullsink
+@end example
+the split filter instance has two output pads, and the overlay filter
+instance two input pads. The first output pad of split is labelled
+"L1", the first input pad of overlay is labelled "L2", and the second
+output pad of split is linked to the second input pad of overlay,
+which are both unlabelled.
+
+In a complete filterchain all the unlabelled filter input and output
+pads must be connected. A filtergraph is considered valid if all the
+filter input and output pads of all the filterchains are connected.
+
+Follows a BNF description for the filtergraph syntax:
+@example
+@var{NAME} ::= sequence of alphanumeric characters and '_'
+@var{LINKLABEL} ::= "[" @var{NAME} "]"
+@var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
+@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
+@var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
+@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
+@var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
+@end example
+
+@c man end FILTERGRAPH DESCRIPTION
+
@chapter Audio Filters
@c man begin AUDIO FILTERS
Below is a description of the currently available video filters.
+@section blackframe
+
+Detect frames that are (almost) completely black. Can be useful to
+detect chapter transitions or commercials. Output lines consist of
+the frame number of the detected frame, the percentage of blackness,
+the position in the file if known or -1 and the timestamp in seconds.
+
+In order to display the output lines, you need to set the loglevel at
+least to the AV_LOG_INFO value.
+
+The filter accepts the syntax:
+@example
+blackframe[=@var{amount}:[@var{threshold}]]
+@end example
+
+@var{amount} is the percentage of the pixels that have to be below the
+threshold, and defaults to 98.
+
+@var{threshold} is the threshold below which a pixel value is
+considered black, and defaults to 32.
+
+@section copy
+
+Copy the input source unchanged to the output. Mainly useful for
+testing purposes.
+
@section crop
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
# corner of the input image.
crop=in_w-100:in_h-100:100:100
-# crop 10 pixels from the lefth and right borders, and 20 pixels from
+# crop 10 pixels from the left and right borders, and 20 pixels from
# the top and bottom borders
"crop=in_w-2*10:in_h-2*20"
# trembling effect
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
-# erratic camera effect depending on timestamp and position
+# erratic camera effect depending on timestamp
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
# set x depending on the value of y
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
@end example
+@section cropdetect
+
+Auto-detect crop size.
+
+Calculate necessary cropping parameters and prints the recommended
+parameters through the logging system. The detected dimensions
+correspond to the non-black area of the input video.
+
+It accepts the syntax:
+@example
+cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
+@end example
+
+@table @option
+
+@item limit
+Threshold, which can be optionally specified from nothing (0) to
+everything (255), defaults to 24.
+
+@item round
+Value which the width/height should be divisible by, defaults to
+16. The offset is automatically adjusted to center the video. Use 2 to
+get only even dimensions (needed for 4:2:2 video). 16 is best when
+encoding to most video codecs.
+
+@item reset
+Counter that determines after how many frames cropdetect will reset
+the previously detected largest video area and start over to detect
+the current optimal crop area. Defaults to 0.
+
+This can be useful when channel logos distort the video area. 0
+indicates never reset and return the largest area encountered during
+playback.
+@end table
+
+@section drawbox
+
+Draw a colored box on the input image.
+
+It accepts the syntax:
+@example
+drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
+@end example
+
+@table @option
+
+@item x, y
+Specify the top left corner coordinates of the box. Default to 0.
+
+@item width, height
+Specify the width and height of the box, if 0 they are interpreted as
+the input width and height. Default to 0.
+
+@item color
+Specify the color of the box to write, it can be the name of a color
+(case insensitive match) or a 0xRRGGBB[AA] sequence.
+@end table
+
+Follow some examples:
+@example
+# draw a black box around the edge of the input image
+drawbox
+
+# draw a box with color red and an opacity of 50%
+drawbox=10:20:200:60:red@@0.5"
+@end example
+
@section fifo
Buffer input images and send them when they are requested.
The filter accepts a list of pixel format names, separated by ":",
for example "yuv420p:monow:rgb24".
-The following command:
-
+Some examples follow:
@example
-./ffmpeg -i in.avi -vf "format=yuv420p" out.avi
-@end example
+# convert the input video to the format "yuv420p"
+format=yuv420p
-will convert the input video to the format "yuv420p".
+# convert the input video to any of the formats in the list
+format=yuv420p:yuv444p:yuv410p
+@end example
+@anchor{frei0r}
@section frei0r
Apply a frei0r effect to the input video.
The filter supports the syntax:
@example
-@var{filter_name}:@var{param1}:@var{param2}:...:@var{paramN}
+@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
@end example
@var{filter_name} is the name to the frei0r effect to load. If the
For more information see:
@url{http://piksel.org/frei0r}
+@section gradfun
+
+Fix the banding artifacts that are sometimes introduced into nearly flat
+regions by truncation to 8bit colordepth.
+Interpolate the gradients that should go where the bands are, and
+dither them.
+
+The filter takes two optional parameters, separated by ':':
+@var{strength}:@var{radius}
+
+@var{strength} is the maximum amount by which the filter will change
+any one pixel. Also the threshold for detecting nearly flat
+regions. Acceptable values range from .51 to 255, default value is
+1.2, out-of-range values will be clipped to the valid range.
+
+@var{radius} is the neighborhood to fit the gradient to. A larger
+radius makes for smoother gradients, but also prevents the filter from
+modifying the pixels near detailed regions. Acceptable values are
+8-32, default value is 16, out-of-range values will be clipped to the
+valid range.
+
+@example
+# default parameters
+gradfun=1.2:16
+
+# omitting radius
+gradfun=1.2
+@end example
+
@section hflip
Flip the input video horizontally.
ffmpeg -i in.avi -vf "hflip" out.avi
@end example
+@section hqdn3d
+
+High precision/quality 3d denoise filter. This filter aims to reduce
+image noise producing smooth images and making still images really
+still. It should enhance compressibility.
+
+It accepts the following optional parameters:
+@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
+
+@table @option
+@item luma_spatial
+a non-negative float number which specifies spatial luma strength,
+defaults to 4.0
+
+@item chroma_spatial
+a non-negative float number which specifies spatial chroma strength,
+defaults to 3.0*@var{luma_spatial}/4.0
+
+@item luma_tmp
+a float number which specifies luma temporal strength, defaults to
+6.0*@var{luma_spatial}/4.0
+
+@item chroma_tmp
+a float number which specifies chroma temporal strength, defaults to
+@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
+@end table
+
@section noformat
Force libavfilter not to use any of the specified pixel formats for the
The filter accepts a list of pixel format names, separated by ":",
for example "yuv420p:monow:rgb24".
-The following command:
-
+Some examples follow:
@example
-./ffmpeg -i in.avi -vf "noformat=yuv420p, vflip" out.avi
-@end example
+# force libavfilter to use a format different from "yuv420p" for the
+# input to the vflip filter
+noformat=yuv420p,vflip
-will make libavfilter use a format different from "yuv420p" for the
-input to the vflip filter.
+# convert the input video to any of the formats not contained in the list
+noformat=yuv420p:yuv444p:yuv410p
+@end example
@section null
Pass the video source unchanged to the output.
-@section ocv_smooth
+@section ocv
-Apply smooth transform using libopencv.
+Apply video transform using libopencv.
To enable this filter install libopencv library and headers and
configure FFmpeg with --enable-libopencv.
-The filter accepts the following parameters:
+The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
+
+@var{filter_name} is the name of the libopencv filter to apply.
+
+@var{filter_params} specifies the parameters to pass to the libopencv
+filter. If not specified the default values are assumed.
+
+Refer to the official libopencv documentation for more precise
+informations:
+@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
+
+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 colums 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=dilate=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=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 meaning and use of those of the dilate filter
+(@pxref{dilate}).
+
+@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
other parameters is 0.
These parameters correspond to the parameters assigned to the
-libopencv function @code{cvSmooth}. Refer to the official libopencv
-documentation for the exact meaning of the parameters:
-@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
+libopencv function @code{cvSmooth}.
+
+@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.
+
+It accepts the parameters: @var{x}:@var{y}.
+
+@var{x} is the x coordinate of the overlayed video on the main video,
+@var{y} is the y coordinate. The parameters are expressions containing
+the following parameters:
+
+@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 overlay_w, overlay_h
+overlay input width and height
+
+@item w, h
+same as @var{overlay_w} and @var{overlay_h}
+@end table
+
+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.
+
+Follow some examples:
+@example
+# draw the overlay at 10 pixels from the bottom right
+# corner of the main video.
+overlay=main_w-overlay_w-10:main_h-overlay_h-10
+
+# insert a transparent PNG logo in the bottom left corner of the input
+movie=logo.png [logo];
+[in][logo] overlay=10:main_h-overlay_h-10 [out]
+
+# insert 2 different transparent PNG logos (second logo on bottom
+# right corner):
+movie=logo1.png [logo1];
+movie=logo2.png [logo2];
+[in][logo1] overlay=10:H-h-10 [in+logo1];
+[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
+
+# 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]
+@end example
+
+You can chain togheter more overlays but the efficiency of such
+approach is yet to be tested.
@section pad
@end table
+For example:
+
+@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
+# row 0, column 40.
+pad=640:480:0:40:violet
+@end example
+
@section pixdesctest
Pixel format descriptor test filter, mainly useful for internal
The default value of @var{width} and @var{height} is 0.
+@section setpts
+
+Change the PTS (presentation timestamp) of the input video frames.
+
+Accept in input an expression evaluated through the eval API, which
+can contain the following constants:
+
+@table @option
+@item PTS
+the presentation timestamp in input
+
+@item PI
+Greek PI
+
+@item PHI
+golden ratio
+
+@item E
+Euler number
+
+@item N
+the count of the input frame, starting from 0.
+
+@item STARTPTS
+the PTS of the first video frame
+
+@item INTERLACED
+tell if the current frame is interlaced
+
+@item POS
+original position in the file of the frame, or undefined if undefined
+for the current frame
+
+@item PREV_INPTS
+previous input PTS
+
+@item PREV_OUTPTS
+previous output PTS
+
+@end table
+
+Some examples follow:
+
+@example
+# start counting PTS from zero
+setpts=PTS-STARTPTS
+
+# fast motion
+setpts=0.5*PTS
+
+# slow motion
+setpts=2.0*PTS
+
+# fixed rate 25 fps
+setpts=N/(25*TB)
+
+# fixed rate 25 fps with some jitter
+setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
+@end example
+
+@section settb
+
+Set the timebase to use for the output frames timestamps.
+It is mainly useful for testing timebase configuration.
+
+It accepts in input an arithmetic expression representing a rational.
+The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
+default timebase), and "intb" (the input timebase).
+
+The default value for the input is "intb".
+
+Follow some examples.
+
+@example
+# set the timebase to 1/25
+settb=1/25
+
+# set the timebase to 1/10
+settb=0.1
+
+#set the timebase to 1001/1000
+settb=1+0.001
+
+#set the timebase to 2*intb
+settb=2*intb
+
+#set the default timebase value
+settb=AVTB
+@end example
+
@section slicify
Pass the images of input video on to next video filter as multiple
Adding this in the beginning of filter chains should make filtering
faster due to better use of the memory cache.
+@section transpose
+
+Transpose rows with columns in the input video and optionally flip it.
+
+It accepts a parameter representing an integer, which can assume the
+values:
+
+@table @samp
+@item 0
+Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
+@example
+L.R L.l
+. . -> . .
+l.r R.r
+@end example
+
+@item 1
+Rotate by 90 degrees clockwise, that is:
+@example
+L.R l.L
+. . -> . .
+l.r r.R
+@end example
+
+@item 2
+Rotate by 90 degrees counterclockwise, that is:
+@example
+L.R R.r
+. . -> . .
+l.r L.l
+@end example
+
+@item 3
+Rotate by 90 degrees clockwise and vertically flip, that is:
+@example
+L.R r.R
+. . -> . .
+l.r l.L
+@end example
+@end table
+
@section unsharp
Sharpen or blur the input video.
@section yadif
-yadif is "yet another deinterlacing filter".
-
-It accepts the syntax:
-@example
-yadif=[@var{mode}[:@var{parity}]]
-@end example
-
-@table @option
-
-@item mode
-Specify the interlacing mode to adopt, accepts one of the following values.
+Deinterlace the input video ("yadif" means "yet another deinterlacing
+filter").
-0: Output 1 frame for each frame.
+It accepts the optional parameters: @var{mode}:@var{parity}.
-1: Output 1 frame for each field.
+@var{mode} specifies the interlacing mode to adopt, accepts one of the
+following values:
-2: Like 0 but skips spatial interlacing check.
-
-3: Like 1 but skips spatial interlacing check.
+@table @option
+@item 0
+output 1 frame for each frame
+@item 1
+output 1 frame for each field
+@item 2
+like 0 but skips spatial interlacing check
+@item 3
+like 1 but skips spatial interlacing check
+@end table
Default value is 0.
-@item parity
-0 if is bottom field first, 1 if the interlaced video is top field
-first, -1 to enable automatic detection.
+@var{parity} specifies the picture field parity assumed for the input
+interlaced video, accepts one of the following values:
+@table @option
+@item 0
+assume bottom field first
+@item 1
+assume top field first
+@item -1
+enable automatic detection
@end table
+Default value is -1.
+If interlacing is unknown or decoder does not export this information,
+top field first will be assumed.
+
@c man end VIDEO FILTERS
@chapter Video Sources
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
It accepts the following parameters:
-@var{width}:@var{height}:@var{pix_fmt_string}
+@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}
All the parameters need to be explicitely defined.
Specify the width and height of the buffered video frames.
@item pix_fmt_string
-
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 timebase_num, timebase_den
+Specify numerator and denomitor of the timebase assumed by the
+timestamps of the buffered frames.
@end table
For example:
@example
-buffer=320:240:yuv410p
+buffer=320:240:yuv410p:1:24
@end example
will instruct the source to accept video frames with size 320x240 and
-with format "yuv410p". Since the pixel format with name "yuv410p"
-corresponds to the number 6 (check the enum PixelFormat definition in
-@file{libavutil/pixfmt.h}), this example corresponds to:
+with format "yuv410p" and assuming 1/24 as the timestamps timebase.
+Since the pixel format with name "yuv410p" corresponds to the number 6
+(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
+this example corresponds to:
@example
-buffer=320:240:6
+buffer=320:240:6:1:24
@end example
@section color
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
@end example
+@section movie
+
+Read a video stream from a movie container.
+
+It accepts the syntax: @var{movie_name}[:@var{options}] where
+@var{movie_name} is the name of the resource to read (not necessarily
+a file but also a device or a stream accessed through some protocol),
+and @var{options} is an optional sequence of @var{key}=@var{value}
+pairs, separated by ":".
+
+The description of the accepted options follows.
+
+@table @option
+
+@item format_name, f
+Specifies the format assumed for the movie to read, and can be either
+the name of a container or an input device. If not specified the
+format is guessed from @var{movie_name} or by probing.
+
+@item seek_point, sp
+Specifies the seek point in seconds, the frames will be output
+starting from this seek point, the parameter is evaluated with
+@code{av_strtod} so the numerical value may be suffixed by an IS
+postfix. Default value is "0".
+
+@item stream_index, si
+Specifies the index of the video stream to read. If the value is -1,
+the best suited video stream will be automatically selected. Default
+value is "-1".
+
+@end table
+
+This filter allows to overlay a second video on top of main input of
+a filtergraph as shown in this graph:
+@example
+input -----------> deltapts0 --> overlay --> output
+ ^
+ |
+movie --> scale--> deltapts1 -------+
+@end example
+
+Some examples follow:
+@example
+# skip 3.2 seconds from the start of the avi file in.avi, and overlay it
+# on top of the input labelled as "in".
+movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
+[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+
+# read from a video4linux2 device, and overlay it on top of the input
+# labelled as "in"
+movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
+[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+
+@end example
+
@section nullsrc
Null video source, never return images. It is mainly useful as a
template and to be employed in analysis / debugging tools.
It accepts as optional parameter a string of the form
-@var{width}:@var{height}, where @var{width} and @var{height} specify the size of
-the configured source.
+@var{width}:@var{height}:@var{timebase}.
-The default values of @var{width} and @var{height} are respectively 352
-and 288 (corresponding to the CIF size format).
+@var{width} and @var{height} specify the size of the configured
+source. The default values of @var{width} and @var{height} are
+respectively 352 and 288 (corresponding to the CIF size format).
+
+@var{timebase} specifies an arithmetic expression representing a
+timebase. The expression can contain the constants "PI", "E", "PHI",
+"AVTB" (the default timebase), and defaults to the value "AVTB".
+
+@section frei0r_src
+
+Provide a frei0r source.
+
+To enable compilation of this filter you need to install the frei0r
+header and configure FFmpeg with --enable-frei0r.
+
+The source supports the syntax:
+@example
+@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
+@end example
+
+@var{size} is the size of the video to generate, may be a string of the
+form @var{width}x@var{height} or a frame size abbreviation.
+@var{rate} is the rate of the video to generate, may be a string of
+the form @var{num}/@var{den} or a frame rate abbreviation.
+@var{src_name} is the name to the frei0r source to load. For more
+information regarding frei0r and how to set the parameters read the
+section "frei0r" (@pxref{frei0r}) in the description of the video
+filters.
+
+Some examples follow:
+@example
+# generate a frei0r partik0l source with size 200x200 and framerate 10
+# which is overlayed on the overlay filter main input
+frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
+@end example
@c man end VIDEO SOURCES
projects / ffmpeg / blobdiff