"=@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.
+initialize the filter instance. It may have one of the two allowed forms:
+@itemize
+
+@item
+A ':'-separated list of @var{key=value} pairs.
+
+@item
+A ':'-separated list of @var{value}. In this case, the keys are assumed to be
+the option names in the order they are declared. E.g. the @code{fade} filter
+declares three options in this order -- @option{type}, @option{start_frame} and
+@option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
+@var{in} is assigned to the option @option{type}, @var{0} to
+@option{start_frame} and @var{30} to @option{nb_frames}.
+
+@end itemize
+
+If the option value itself is a list of items (e.g. the @code{format} filter
+takes a list of pixel formats), the items in the list are usually separated by
+'|'.
The list of arguments can be quoted using the character "'" as initial
and ending mark, and the character '\' for escaping the characters
@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{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
@var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
@end example
@table @option
@item sample_fmts
-A comma-separated list of requested sample formats.
+A '|'-separated list of requested sample formats.
@item sample_rates
-A comma-separated list of requested sample rates.
+A '|'-separated list of requested sample rates.
@item channel_layouts
-A comma-separated list of requested channel layouts.
+A '|'-separated list of requested channel layouts.
@end table
For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
@example
-aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo
+aformat=sample_fmts=u8|s16:channel_layouts=stereo
@end example
@section amix
Pass the audio source unchanged to the output.
+@section ashowinfo
+
+Show a line containing various information for each input audio frame.
+The input audio 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, in time base units; the time base
+depends on the filter input pad, and is usually 1/@var{sample_rate}.
+
+@item pts_time
+presentation timestamp of the input frame in seconds
+
+@item fmt
+sample format
+
+@item chlayout
+channel layout
+
+@item rate
+sample rate for the audio frame
+
+@item nb_samples
+number of samples (per channel) in the frame
+
+@item checksum
+Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
+the data is treated as if all the planes were concatenated.
+
+@item plane_checksums
+A list of Adler-32 checksums for each data plane.
+@end table
+
@section asplit
Split input audio into several identical outputs.
@table @option
@item compensate
-Enable stretching/squeezing the data to make it match the timestamps.
+Enable stretching/squeezing the data to make it match the timestamps. Disabled
+by default. When disabled, time gaps are covered with silence.
@item min_delta
Minimum difference between timestamps and audio data (in seconds) to trigger
-adding/dropping samples.
+adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
+this filter, try setting this parameter to 0.
@item max_comp
-Maximum compensation in samples per second.
+Maximum compensation in samples per second. Relevant only with compensate=1.
+Default value 500.
+
+@item first_pts
+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 or to trim any samples
+with a negative pts due to encoder delay.
@end table
whenever conversion is needed. Use the @var{aformat} filter to force a specific
conversion.
+@section volume
+
+Adjust the input audio volume.
+
+The filter accepts the following named parameters:
+@table @option
+
+@item volume
+Expresses how the audio volume will be increased or decreased.
+
+Output values are clipped to the maximum value.
+
+The output audio volume is given by the relation:
+@example
+@var{output_volume} = @var{volume} * @var{input_volume}
+@end example
+
+Default value for @var{volume} is 1.0.
+
+@item precision
+Mathematical precision.
+
+This determines which input sample formats will be allowed, which affects the
+precision of the volume scaling.
+
+@table @option
+@item fixed
+8-bit fixed-point; limits input sample format to U8, S16, and S32.
+@item float
+32-bit floating-point; limits input sample format to FLT. (default)
+@item double
+64-bit floating-point; limits input sample format to DBL.
+@end table
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Halve the input audio volume:
+@example
+volume=volume=0.5
+volume=volume=1/2
+volume=volume=-6.0206dB
+@end example
+
+@item
+Increase input audio power by 6 decibels using fixed-point precision:
+@example
+volume=volume=6dB:precision=fixed
+@end example
+@end itemize
+
@c man end AUDIO FILTERS
@chapter Audio Sources
of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
Check the channel_layout_map definition in
-@file{libavcodec/audioconvert.c} for the mapping between strings and
+@file{libavutil/channel_layout.c} for the mapping between strings and
channel layout values.
Follow some examples:
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
+The filter accepts the following options:
+
+@table @option
+
+@item amount
+The percentage of the pixels that have to be below the threshold, defaults to
+98.
-@var{amount} is the percentage of the pixels that have to be below the
-threshold, and defaults to 98.
+@item threshold
+Threshold below which a pixel value is considered black, defaults to 32.
-@var{threshold} is the threshold below which a pixel value is
-considered black, and defaults to 32.
+@end table
@section boxblur
Apply boxblur algorithm to the input video.
-This filter accepts the parameters:
-@var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
+This filter accepts the following options:
+
+@table @option
+
+@item luma_radius
+@item luma_power
+@item chroma_radius
+@item chroma_power
+@item alpha_radius
+@item alpha_power
+
+@end table
Chroma and alpha parameters are optional, if not specified they default
to the corresponding values set for @var{luma_radius} and
Apply a boxblur filter with luma, chroma, and alpha radius
set to 2:
@example
-boxblur=2:1
+boxblur=luma_radius=2:luma_power=1
@end example
@item
@item
Set luma and chroma radius to a fraction of the video dimension
@example
-boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
+boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
@end example
@end itemize
@section crop
-Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
+Crop the input video to given dimensions.
+
+This filter accepts the following options:
+
+@table @option
+
+@item out_w
+Width of the output video.
+
+@item out_h
+Height of the output video.
+
+@item x
+Horizontal position, in the input video, of the left edge of the output video.
+
+@item y
+Vertical position, in the input video, of the top edge of the output video.
+
+@end table
The parameters are expressions containing the following constants:
@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
Follow some examples:
@example
# crop the central input area with size 100x100
-crop=100:100
+crop=out_w=100:out_h=100
# crop the central input area with size 2/3 of the input video
-"crop=2/3*in_w:2/3*in_h"
+"crop=out_w=2/3*in_w:out_h=2/3*in_h"
# crop the input video central square
-crop=in_h
+crop=out_w=in_h
# 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.
-crop=in_w-100:in_h-100:100:100
+crop=out_w=in_w-100:out_h=in_h-100:x=100:y=100
# 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"
+"crop=out_w=in_w-2*10:out_h=in_h-2*20"
# keep only the bottom right quarter of the input image
-"crop=in_w/2:in_h/2:in_w/2:in_h/2"
+"crop=out_w=in_w/2:out_h=in_h/2:x=in_w/2:y=in_h/2"
# crop height for getting Greek harmony
-"crop=in_w:1/PHI*in_w"
+"crop=out_w=in_w:out_h=1/PHI*in_w"
# 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
-"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)"
+"crop=out_w=in_w/2:out_h=in_h/2:x=(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):y=(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)"
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
+This filter accepts the following options:
@table @option
Libavfilter will try to pick one that is supported for the input to
the next filter.
-The filter accepts a list of pixel format names, separated by ":",
-for example "yuv420p:monow:rgb24".
+This filter accepts the following parameters:
+@table @option
+
+@item pix_fmts
+A '|'-separated list of pixel format names, for example
+"pix_fmts=yuv420p|monow|rgb24".
+
+@end table
Some examples follow:
@example
# convert the input video to the format "yuv420p"
-format=yuv420p
+format=pix_fmts=yuv420p
# convert the input video to any of the formats in the list
-format=yuv420p:yuv444p:yuv410p
+format=pix_fmts=yuv420p|yuv444p|yuv410p
@end example
@section fps
@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
+regions. Acceptable values range from .51 to 64, 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
The @var{lut} filter requires either YUV or RGB pixel formats in
input, and accepts the options:
@table @option
-@var{c0} (first pixel component)
-@var{c1} (second pixel component)
-@var{c2} (third pixel component)
-@var{c3} (fourth pixel component, corresponds to the alpha component)
+@item @var{c0} (first pixel component)
+@item @var{c1} (second pixel component)
+@item @var{c2} (third pixel component)
+@item @var{c3} (fourth pixel component, corresponds to the alpha component)
@end table
The exact component associated to each option depends on the format in
The @var{lutrgb} filter requires RGB pixel formats in input, and
accepts the options:
@table @option
-@var{r} (red component)
-@var{g} (green component)
-@var{b} (blue component)
-@var{a} (alpha component)
+@item @var{r} (red component)
+@item @var{g} (green component)
+@item @var{b} (blue component)
+@item @var{a} (alpha component)
@end table
The @var{lutyuv} filter requires YUV pixel formats in input, and
accepts the options:
@table @option
-@var{y} (Y/luminance component)
-@var{u} (U/Cb component)
-@var{v} (V/Cr component)
-@var{a} (alpha component)
+@item @var{y} (Y/luminance component)
+@item @var{u} (U/Cb component)
+@item @var{v} (V/Cr component)
+@item @var{a} (alpha component)
@end table
The expressions can contain the following constants and functions:
This filter accepts an integer in input, if non-zero it negates the
alpha component (if available). The default value in input is 0.
+@section noformat
+
Force libavfilter not to use any of the specified pixel formats for the
input to the next filter.
-The filter accepts a list of pixel format names, separated by ":",
-for example "yuv420p:monow:rgb24".
+This filter accepts the following parameters:
+@table @option
+
+@item pix_fmts
+A '|'-separated list of pixel format names, for example
+"pix_fmts=yuv420p|monow|rgb24".
+
+@end table
Some examples follow:
@example
# force libavfilter to use a format different from "yuv420p" for the
# input to the vflip filter
-noformat=yuv420p,vflip
+noformat=pix_fmts=yuv420p,vflip
# convert the input video to any of the formats not contained in the list
-noformat=yuv420p:yuv444p:yuv410p
+noformat=yuv420p|yuv444p|yuv410p
@end example
@section null
@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)
@end table
The default value of the select expression is "1".
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 filter accepts a parameter string which represents the wanted
-display aspect ratio.
-The parameter can be a floating point number string, or an expression
-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 "0:1".
+This filter accepts the following options:
+
+@table @option
+
+@item dar
+Output display aspect ratio, as a rational or a decimal number.
+
+@end table
For example to change the display aspect ratio to 16:9, specify:
@example
-setdar=16:9
+setdar=dar=16/9
# the above is equivalent to
-setdar=1.77777
+setdar=dar=1.77777
@end example
See also the @ref{setsar} filter documentation.
@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
+@item RTCTIME
+wallclock (RTC) time in microseconds
+
+@item RTCSTART
+wallclock (RTC) time at the start of the movie in microseconds
+
@end table
Some examples follow:
# fixed rate 25 fps with some jitter
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
+
+# generate timestamps from a "live source" and rebase onto the current timebase
+setpts='(RTCTIME - RTCSTART) / (TB * 1000000)"
@end example
@anchor{setsar}
changed by later filters in the filterchain, e.g. if another "setsar"
or a "setdar" filter is applied.
-The filter accepts a parameter string which represents the wanted
-sample aspect ratio.
-The parameter can be a floating point number string, or an expression
-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 "0:1".
+This filter accepts the following options:
+
+@table @option
+
+@item sar
+Output sample aspect ratio, as a rational or decimal number.
+
+@end table
For example to change the sample aspect ratio to 10:11, specify:
@example
-setsar=10:11
+setsar=sar=10/11
@end example
@section settb
"[@var{c0} @var{c1} @var{c2} @var{c3}]"
@end table
-@section slicify
-
-Pass the images of input video on to next video filter as multiple
-slices.
-
-@example
-./avconv -i in.avi -vf "slicify=32" out.avi
-@end example
-
-The filter accepts the slice height as parameter. If the parameter is
-not specified it will use the default value of 16.
-
-Adding this in the beginning of filter chains should make filtering
-faster due to better use of the memory cache.
-
@section split
Split input video into several identical outputs.
This source is mainly intended for a programmatic use, in particular
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
-It accepts the following parameters:
-@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
+This filter accepts the following parameters:
-All the parameters need to be explicitly defined.
+@table @option
-Follows the list of the accepted parameters.
+@item width
+Input video width.
-@table @option
+@item height
+Input video height.
-@item width, height
-Specify the width and height of the buffered video frames.
+@item pix_fmt
+Name of the input video pixel format.
-@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 time_base
+The time base used for input timestamps.
-@item timebase_num, timebase_den
-Specify numerator and denomitor of the timebase assumed by the
-timestamps of the buffered frames.
+@item sar
+Sample (pixel) aspect ratio of the input video.
-@item sample_aspect_ratio.num, sample_aspect_ratio.den
-Specify numerator and denominator of the sample aspect ratio assumed
-by the video frames.
@end table
For example:
@example
-buffer=320:240:yuv410p:1:24:1:1
+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 PixelFormat definition in @file{libavutil/pixfmt.h}),
-this example corresponds to:
-@example
-buffer=320:240:6:1:24
-@end example
@section color
Read a video stream from a movie container.
+Note that this source is a hack that bypasses the standard input path. It can be
+useful in applications that do not support arbitrary filter graphs, but its use
+is discouraged in those that do. Specifically in @command{avconv} this filter
+should never be used, the @option{-filter_complex} option fully replaces it.
+
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),