use a complex filter graph. For example, the following one:
@example
-input --> split --> fifo -----------------------> overlay --> output
- | ^
- | |
- +------> fifo --> crop --> vflip --------+
+input --> split ---------------------> overlay --> output
+ | ^
+ | |
+ +-----> crop --> vflip -------+
@end example
splits the stream in two streams, sends one stream through the crop filter
overlaying it on top. You can use the following command to achieve this:
@example
-ffmpeg -i input -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, vflip [T2]" output
+ffmpeg -i input -vf "[in] split [T1], [T2] overlay=0:H/2 [out]; [T1] crop=iw:ih/2:0:ih/2, vflip [T2]" output
@end example
The result will be that in output the top half of the video is mirrored
Filters are loaded using the @var{-vf} or @var{-af} option passed to
@command{ffmpeg} or to @command{ffplay}. Filters in the same linear
-chain are separated by commas. In our example, @var{split, fifo,
-overlay} are in one linear chain, and @var{fifo, crop, vflip} are in
+chain are separated by commas. In our example, @var{split,
+overlay} are in one linear chain, and @var{crop, vflip} are in
another. The points where the linear chains join are labeled by names
enclosed in square brackets. In our example, that is @var{[T1]} and
@var{[T2]}. The special labels @var{[in]} and @var{[out]} are the points
drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'
@end example
-See the @ref{quoting_and_escaping, Quoting and escaping} section for
-more information about the escaping and quoting rules adopted by
+See the ``Quoting and escaping'' section in the ffmpeg-utils manual
+for more information about the escaping and quoting rules adopted by
FFmpeg.
@c man end FILTERGRAPH DESCRIPTION
Pass the audio source unchanged to the output.
+@section apad
+
+Pad the end of a audio stream with silence, this can be used together with
+-shortest to extend audio streams to the same length as the video stream.
+
@section aresample
Resample the input audio to the specified parameters. If none are specified
@item dolby
Dolby matrixed stereo encoding
-@item dolby
+@item dplii
Dolby Pro Logic II matrixed stereo encoding
@end table
Default value 500.
@item first_pts
-Assume the first pts should be this value.
+Assume the first pts should be this value. The time base is 1 / sample rate.
This allows for padding/trimming at the start of stream. By default, no
assumption is made about the first frame's expected pts, so no padding or
trimming is done. For example, this could be set to 0 to pad the beginning with
-silence if an audio stream starts after the video stream.
+silence if an audio stream starts after the video stream or to trim any samples
+with a negative pts due to encoder delay.
@end table
@section crop
-Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
+Crop the input video.
-The @var{keep_aspect} parameter is optional, if specified and set to a
-non-zero value will force the output display aspect ratio to be the
-same of the input, by changing the output sample aspect ratio.
+This filter accepts a list of @var{key}=@var{value} pairs as argument,
+separated by ':'. If the key of the first options is omitted, the
+arguments are interpreted according to the syntax
+@var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}.
+
+A description of the accepted options follows:
+@table @option
+@item w, out_w
+Set the crop area width. It defaults to @code{iw}.
+This expression is evaluated only once during the filter
+configuration.
+
+@item h, out_h
+Set the crop area width. It defaults to @code{ih}.
+This expression is evaluated only once during the filter
+configuration.
+
+@item x
+Set the expression for the x top-left coordinate of the cropped area.
+It defaults to @code{(in_w-out_w)/2}.
+This expression is evaluated per-frame.
+
+@item y
+Set the expression for the y top-left coordinate of the cropped area.
+It defaults to @code{(in_h-out_h)/2}.
+This expression is evaluated per-frame.
+
+@item keep_aspect
+If set to 1 will force the output display aspect ratio
+to be the same of the input, by changing the output sample aspect
+ratio. It defaults to 0.
+@end table
The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
expressions containing the following constants:
@end table
-The @var{out_w} and @var{out_h} parameters specify the expressions for
-the width and height of the output (cropped) video. They are
-evaluated just at the configuration of the filter.
-
-The default value of @var{out_w} is "in_w", and the default value of
-@var{out_h} is "in_h".
-
The expression for @var{out_w} may depend on the value of @var{out_h},
and the expression for @var{out_h} may depend on @var{out_w}, but they
cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
are evaluated for each frame. If the evaluated value is not valid, it
is approximated to the nearest valid value.
-The default value of @var{x} is "(in_w-out_w)/2", and the default
-value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
-the center of the input image.
-
The expression for @var{x} may depend on @var{y}, and the expression
for @var{y} may depend on @var{x}.
-Follow some examples:
+@subsection Examples
+@itemize
+@item
+Crop area with size 100x100 at position (12,34).
+@example
+crop=100:100:12:34
+@end example
+
+Using named options, the example above becomes:
+@example
+crop=w=100:h=100:x=12:y=34
+@end example
+
+@item
+Crop the central input area with size 100x100:
@example
-# crop the central input area with size 100x100
crop=100:100
+@end example
-# crop the central input area with size 2/3 of the input video
-"crop=2/3*in_w:2/3*in_h"
+@item
+Crop the central input area with size 2/3 of the input video:
+@example
+crop=2/3*in_w:2/3*in_h
+@end example
-# crop the input video central square
+@item
+Crop the input video central square:
+@example
crop=in_h
+@end example
-# delimit the rectangle with the top-left corner placed at position
-# 100:100 and the right-bottom corner corresponding to the right-bottom
-# corner of the input image.
+@item
+Delimit the rectangle with the top-left corner placed at position
+100:100 and the right-bottom corner corresponding to the right-bottom
+corner of the input image:
+@example
crop=in_w-100:in_h-100:100:100
+@end example
-# 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"
+@item
+Crop 10 pixels from the left and right borders, and 20 pixels from
+the top and bottom borders
+@example
+crop=in_w-2*10:in_h-2*20
+@end example
-# keep only the bottom right quarter of the input image
-"crop=in_w/2:in_h/2:in_w/2:in_h/2"
+@item
+Keep only the bottom right quarter of the input image:
+@example
+crop=in_w/2:in_h/2:in_w/2:in_h/2
+@end example
-# crop height for getting Greek harmony
-"crop=in_w:1/PHI*in_w"
+@item
+Crop height for getting Greek harmony:
+@example
+crop=in_w:1/PHI*in_w
+@end example
-# 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)"
+@item
+Appply trembling effect:
+@example
+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)
+@end example
-# 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)"
+@item
+Apply erratic camera effect depending on timestamp:
+@example
+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)"
+@end example
-# set x depending on the value of y
-"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
+@item
+Set x depending on the value of y:
+@example
+crop=in_w/2:in_h/2:y:10+10*sin(n/10)
@end example
+@end itemize
@section cropdetect
lossy compression, because compression tends to lose the dither and
bring back the bands.
-The filter takes two optional parameters, separated by ':':
-@var{strength}:@var{radius}
+The filter 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
-@var{strength} is the maximum amount by which the filter will change
+@item strength
+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.
+regions. Acceptable values range from @code{0.51} to @code{64}, default value
+is @code{1.2}.
-@var{radius} is the neighborhood to fit the gradient to. A larger
+@item radius
+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.
+@code{8-32}, default value is @code{16}.
+
+@end table
+
+Alternatively, the options can be specified as a flat string:
+@var{strength}[:@var{radius}]
+@subsection Examples
+
+@itemize
+@item
+Apply the filter with a @code{3.5} strength and radius of @code{8}:
@example
-# default parameters
-gradfun=1.2:16
+gradfun=3.5:8
+@end example
-# omitting radius
-gradfun=1.2
+@item
+Specify radius, omitting the strength (which will fall-back to the default
+value):
+@example
+gradfun=radius=8
@end example
+@end itemize
+
@section hflip
Flip the input video horizontally.
@end example
@end itemize
-@section select
-Select frames to pass in output.
-
-It accepts in input an expression, which is evaluated for each input
-frame. If the expression is evaluated to a non-zero value, the frame
-is selected and passed to the output, otherwise it is discarded.
-
-The expression can contain the following constants:
-
-@table @option
-@item n
-the sequential number of the filtered frame, starting from 0
-
-@item selected_n
-the sequential number of the selected frame, starting from 0
-
-@item prev_selected_n
-the sequential number of the last selected frame, NAN if undefined
-
-@item TB
-timebase of the input timestamps
-
-@item pts
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in @var{TB} units, NAN if undefined
-
-@item t
-the PTS (Presentation TimeStamp) of the filtered video frame,
-expressed in seconds, NAN if undefined
-
-@item prev_pts
-the PTS of the previously filtered video frame, NAN if undefined
-
-@item prev_selected_pts
-the PTS of the last previously filtered video frame, NAN if undefined
-
-@item prev_selected_t
-the PTS of the last previously selected video frame, NAN if undefined
-
-@item start_pts
-the PTS of the first video frame in the video, NAN if undefined
-
-@item start_t
-the time of the first video frame in the video, NAN if undefined
-
-@item pict_type
-the type of the filtered frame, can assume one of the following
-values:
-@table @option
-@item I
-@item P
-@item B
-@item S
-@item SI
-@item SP
-@item BI
-@end table
-
-@item interlace_type
-the frame interlace type, can assume one of the following values:
-@table @option
-@item PROGRESSIVE
-the frame is progressive (not interlaced)
-@item TOPFIRST
-the frame is top-field-first
-@item BOTTOMFIRST
-the frame is bottom-field-first
-@end table
-
-@item key
-1 if the filtered frame is a key-frame, 0 otherwise
-
-@item pos
-the position in the file of the filtered frame, -1 if the information
-is not available (e.g. for synthetic video)
-
-@item scene
-value between 0 and 1 to indicate a new scene; a low value reflects a low
-probability for the current frame to introduce a new scene, while a higher
-value means the current frame is more likely to be one (see the example below)
-
-@end table
-
-The default value of the select expression is "1".
-
-Some examples follow:
-
-@example
-# select all frames in input
-select
-
-# the above is the same as:
-select=1
-
-# skip all frames:
-select=0
-
-# select only I-frames
-select='eq(pict_type\,I)'
-
-# select one frame every 100
-select='not(mod(n\,100))'
-
-# select only frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)'
-
-# select only I frames contained in the 10-20 time interval
-select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
-
-# select frames with a minimum distance of 10 seconds
-select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
-@end example
-
-Complete example to create a mosaic of the first scenes:
-
-@example
-ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
-@end example
-
-Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
-choice.
-
@section setdar, setsar
The @code{setdar} filter sets the Display Aspect Ratio for the filter
Transpose rows with columns in the input video and optionally flip it.
-This filter accepts the following named parameters:
+The filter accepts parameters as a list of @var{key}=@var{value}
+pairs, separated by ':'. If the key of the first options is omitted,
+the arguments are interpreted according to the syntax
+@var{dir}:@var{passthrough}.
@table @option
@item dir
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 unsharp
Sharpen or blur the input video.
Below is a description of the currently available multimedia filters.
+@section aselect, select
+Select frames to pass in output.
+
+These filters accept a single option @option{expr} or @option{e}
+specifying the select expression, which can be specified either by
+specyfing @code{expr=VALUE} or specifying the expression
+alone.
+
+The select expression is evaluated for each input frame. If the
+evaluation result is a non-zero value, the frame is selected and
+passed to the output, otherwise it is discarded.
+
+The expression can contain the following constants:
+
+@table @option
+@item n
+the sequential number of the filtered frame, starting from 0
+
+@item selected_n
+the sequential number of the selected frame, starting from 0
+
+@item prev_selected_n
+the sequential number of the last selected frame, NAN if undefined
+
+@item TB
+timebase of the input timestamps
+
+@item pts
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in @var{TB} units, NAN if undefined
+
+@item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+@item prev_pts
+the PTS of the previously filtered video frame, NAN if undefined
+
+@item prev_selected_pts
+the PTS of the last previously filtered video frame, NAN if undefined
+
+@item prev_selected_t
+the PTS of the last previously selected video frame, NAN if undefined
+
+@item start_pts
+the PTS of the first video frame in the video, NAN if undefined
+
+@item start_t
+the time of the first video frame in the video, NAN if undefined
+
+@item pict_type @emph{(video only)}
+the type of the filtered frame, can assume one of the following
+values:
+@table @option
+@item I
+@item P
+@item B
+@item S
+@item SI
+@item SP
+@item BI
+@end table
+
+@item interlace_type @emph{(video only)}
+the frame interlace type, can assume one of the following values:
+@table @option
+@item PROGRESSIVE
+the frame is progressive (not interlaced)
+@item TOPFIRST
+the frame is top-field-first
+@item BOTTOMFIRST
+the frame is bottom-field-first
+@end table
+
+@item consumed_sample_n @emph{(audio only)}
+the number of selected samples before the current frame
+
+@item samples_n @emph{(audio only)}
+the number of samples in the current frame
+
+@item sample_rate @emph{(audio only)}
+the input sample rate
+
+@item key
+1 if the filtered frame is a key-frame, 0 otherwise
+
+@item pos
+the position in the file of the filtered frame, -1 if the information
+is not available (e.g. for synthetic video)
+
+@item scene @emph{(video only)}
+value between 0 and 1 to indicate a new scene; a low value reflects a low
+probability for the current frame to introduce a new scene, while a higher
+value means the current frame is more likely to be one (see the example below)
+
+@end table
+
+The default value of the select expression is "1".
+
+@subsection Examples
+
+@itemize
+@item
+Select all frames in input:
+@example
+select
+@end example
+
+The example above is the same as:
+@example
+select=1
+@end example
+
+@item
+Skip all frames:
+@example
+select=0
+@end example
+
+@item
+Select only I-frames:
+@example
+select='eq(pict_type\,I)'
+@end example
+
+@item
+Select one frame every 100:
+@example
+select='not(mod(n\,100))'
+@end example
+
+@item
+Select only frames contained in the 10-20 time interval:
+@example
+select='gte(t\,10)*lte(t\,20)'
+@end example
+
+@item
+Select only I frames contained in the 10-20 time interval:
+@example
+select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
+@end example
+
+@item
+Select frames with a minimum distance of 10 seconds:
+@example
+select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
+@end example
+
+@item
+Use aselect to select only audio frames with samples number > 100:
+@example
+aselect='gt(samples_n\,100)'
+@end example
+
+@item
+Create a mosaic of the first scenes:
+@example
+ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+@end example
+
+Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
+choice.
+@end itemize
+
@section asendcmd, sendcmd
Send commands to filters in the filtergraph.
postfix. Default value is "0".
@item streams, s
-Specifies the streams to read. Several streams can be specified, separated
-by "+". The source will then have as many outputs, in the same order. The
-syntax is explained in the @ref{Stream specifiers} chapter. Two special
-names, "dv" and "da" specify respectively the default (best suited) video
-and audio stream. Default is "dv", or "da" if the filter is called as
-"amovie".
+Specifies the streams to read. Several streams can be specified,
+separated by "+". The source will then have as many outputs, in the
+same order. The syntax is explained in the ``Stream specifiers''
+section in the ffmpeg manual. Two special names, "dv" and "da" specify
+respectively the default (best suited) video and audio stream. Default
+is "dv", or "da" if the filter is called as "amovie".
@item stream_index, si
Specifies the index of the video stream to read. If the value is -1,
projects / ffmpeg / blobdiff