1 @chapter Filtergraph description
2 @c man begin FILTERGRAPH DESCRIPTION
4 A filtergraph is a directed graph of connected filters. It can contain
5 cycles, and there can be multiple links between a pair of
6 filters. Each link has one input pad on one side connecting it to one
7 filter from which it takes its input, and one output pad on the other
8 side connecting it to the one filter accepting its output.
10 Each filter in a filtergraph is an instance of a filter class
11 registered in the application, which defines the features and the
12 number of input and output pads of the filter.
14 A filter with no input pads is called a "source", a filter with no
15 output pads is called a "sink".
17 @anchor{Filtergraph syntax}
18 @section Filtergraph syntax
20 A filtergraph can be represented using a textual representation, which is
21 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
22 options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
23 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
24 @file{libavfilter/avfilter.h}.
26 A filterchain consists of a sequence of connected filters, each one
27 connected to the previous one in the sequence. A filterchain is
28 represented by a list of ","-separated filter descriptions.
30 A filtergraph consists of a sequence of filterchains. A sequence of
31 filterchains is represented by a list of ";"-separated filterchain
34 A filter is represented by a string of the form:
35 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
37 @var{filter_name} is the name of the filter class of which the
38 described filter is an instance of, and has to be the name of one of
39 the filter classes registered in the program.
40 The name of the filter class is optionally followed by a string
43 @var{arguments} is a string which contains the parameters used to
44 initialize the filter instance. It may have one of the two allowed forms:
48 A ':'-separated list of @var{key=value} pairs.
51 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
52 the option names in the order they are declared. E.g. the @code{fade} filter
53 declares three options in this order -- @option{type}, @option{start_frame} and
54 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
55 @var{in} is assigned to the option @option{type}, @var{0} to
56 @option{start_frame} and @var{30} to @option{nb_frames}.
60 If the option value itself is a list of items (e.g. the @code{format} filter
61 takes a list of pixel formats), the items in the list are usually separated by
64 The list of arguments can be quoted using the character "'" as initial
65 and ending mark, and the character '\' for escaping the characters
66 within the quoted text; otherwise the argument string is considered
67 terminated when the next special character (belonging to the set
68 "[]=;,") is encountered.
70 The name and arguments of the filter are optionally preceded and
71 followed by a list of link labels.
72 A link label allows to name a link and associate it to a filter output
73 or input pad. The preceding labels @var{in_link_1}
74 ... @var{in_link_N}, are associated to the filter input pads,
75 the following labels @var{out_link_1} ... @var{out_link_M}, are
76 associated to the output pads.
78 When two link labels with the same name are found in the
79 filtergraph, a link between the corresponding input and output pad is
82 If an output pad is not labelled, it is linked by default to the first
83 unlabelled input pad of the next filter in the filterchain.
84 For example in the filterchain:
86 nullsrc, split[L1], [L2]overlay, nullsink
88 the split filter instance has two output pads, and the overlay filter
89 instance two input pads. The first output pad of split is labelled
90 "L1", the first input pad of overlay is labelled "L2", and the second
91 output pad of split is linked to the second input pad of overlay,
92 which are both unlabelled.
94 In a complete filterchain all the unlabelled filter input and output
95 pads must be connected. A filtergraph is considered valid if all the
96 filter input and output pads of all the filterchains are connected.
98 Libavfilter will automatically insert scale filters where format
99 conversion is required. It is possible to specify swscale flags
100 for those automatically inserted scalers by prepending
101 @code{sws_flags=@var{flags};}
102 to the filtergraph description.
104 Follows a BNF description for the filtergraph syntax:
106 @var{NAME} ::= sequence of alphanumeric characters and '_'
107 @var{LINKLABEL} ::= "[" @var{NAME} "]"
108 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
109 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
110 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
111 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
112 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
115 @c man end FILTERGRAPH DESCRIPTION
117 @chapter Audio Filters
118 @c man begin AUDIO FILTERS
120 When you configure your Libav build, you can disable any of the
121 existing filters using --disable-filters.
122 The configure output will show the audio filters included in your
125 Below is a description of the currently available audio filters.
129 Convert the input audio to one of the specified formats. The framework will
130 negotiate the most appropriate format to minimize conversions.
132 The filter accepts the following named parameters:
136 A '|'-separated list of requested sample formats.
139 A '|'-separated list of requested sample rates.
141 @item channel_layouts
142 A '|'-separated list of requested channel layouts.
146 If a parameter is omitted, all values are allowed.
148 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
150 aformat=sample_fmts=u8|s16:channel_layouts=stereo
155 Mixes multiple audio inputs into a single output.
159 avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
161 will mix 3 input audio streams to a single output with the same duration as the
162 first input and a dropout transition time of 3 seconds.
164 The filter accepts the following named parameters:
168 Number of inputs. If unspecified, it defaults to 2.
171 How to determine the end-of-stream.
175 Duration of longest input. (default)
178 Duration of shortest input.
181 Duration of first input.
185 @item dropout_transition
186 Transition time, in seconds, for volume renormalization when an input
187 stream ends. The default value is 2 seconds.
193 Pass the audio source unchanged to the output.
197 Show a line containing various information for each input audio frame.
198 The input audio is not modified.
200 The shown line contains a sequence of key/value pairs of the form
201 @var{key}:@var{value}.
203 A description of each shown parameter follows:
207 sequential number of the input frame, starting from 0
210 Presentation timestamp of the input frame, in time base units; the time base
211 depends on the filter input pad, and is usually 1/@var{sample_rate}.
214 presentation timestamp of the input frame in seconds
223 sample rate for the audio frame
226 number of samples (per channel) in the frame
229 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
230 the data is treated as if all the planes were concatenated.
232 @item plane_checksums
233 A list of Adler-32 checksums for each data plane.
238 Split input audio into several identical outputs.
240 The filter accepts a single parameter which specifies the number of outputs. If
241 unspecified, it defaults to 2.
245 avconv -i INPUT -filter_complex asplit=5 OUTPUT
247 will create 5 copies of the input audio.
250 Synchronize audio data with timestamps by squeezing/stretching it and/or
251 dropping samples/adding silence when needed.
253 The filter accepts the following named parameters:
257 Enable stretching/squeezing the data to make it match the timestamps. Disabled
258 by default. When disabled, time gaps are covered with silence.
261 Minimum difference between timestamps and audio data (in seconds) to trigger
262 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
263 this filter, try setting this parameter to 0.
266 Maximum compensation in samples per second. Relevant only with compensate=1.
270 Assume the first pts should be this value. The time base is 1 / sample rate.
271 This allows for padding/trimming at the start of stream. By default, no
272 assumption is made about the first frame's expected pts, so no padding or
273 trimming is done. For example, this could be set to 0 to pad the beginning with
274 silence if an audio stream starts after the video stream or to trim any samples
275 with a negative pts due to encoder delay.
279 @section channelsplit
280 Split each channel in input audio stream into a separate output stream.
282 This filter accepts the following named parameters:
285 Channel layout of the input stream. Default is "stereo".
288 For example, assuming a stereo input MP3 file
290 avconv -i in.mp3 -filter_complex channelsplit out.mkv
292 will create an output Matroska file with two audio streams, one containing only
293 the left channel and the other the right channel.
295 To split a 5.1 WAV file into per-channel files
297 avconv -i in.wav -filter_complex
298 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
299 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
300 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
305 Remap input channels to new locations.
307 This filter accepts the following named parameters:
310 Channel layout of the output stream.
313 Map channels from input to output. The argument is a '|'-separated list of
314 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
315 @var{in_channel} form. @var{in_channel} can be either the name of the input
316 channel (e.g. FL for front left) or its index in the input channel layout.
317 @var{out_channel} is the name of the output channel or its index in the output
318 channel layout. If @var{out_channel} is not given then it is implicitly an
319 index, starting with zero and increasing by one for each mapping.
322 If no mapping is present, the filter will implicitly map input channels to
323 output channels preserving index.
325 For example, assuming a 5.1+downmix input MOV file
327 avconv -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
329 will create an output WAV file tagged as stereo from the downmix channels of
332 To fix a 5.1 WAV improperly encoded in AAC's native channel order
334 avconv -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
338 Join multiple input streams into one multi-channel stream.
340 The filter accepts the following named parameters:
344 Number of input streams. Defaults to 2.
347 Desired output channel layout. Defaults to stereo.
350 Map channels from inputs to output. The argument is a '|'-separated list of
351 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
352 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
353 can be either the name of the input channel (e.g. FL for front left) or its
354 index in the specified input stream. @var{out_channel} is the name of the output
358 The filter will attempt to guess the mappings when those are not specified
359 explicitly. It does so by first trying to find an unused matching input channel
360 and if that fails it picks the first unused input channel.
362 E.g. to join 3 inputs (with properly set channel layouts)
364 avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
367 To build a 5.1 output from 6 single-channel streams:
369 avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
370 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
375 Convert the audio sample format, sample rate and channel layout. This filter is
376 not meant to be used directly, it is inserted automatically by libavfilter
377 whenever conversion is needed. Use the @var{aformat} filter to force a specific
382 Adjust the input audio volume.
384 The filter accepts the following named parameters:
388 Expresses how the audio volume will be increased or decreased.
390 Output values are clipped to the maximum value.
392 The output audio volume is given by the relation:
394 @var{output_volume} = @var{volume} * @var{input_volume}
397 Default value for @var{volume} is 1.0.
400 Mathematical precision.
402 This determines which input sample formats will be allowed, which affects the
403 precision of the volume scaling.
407 8-bit fixed-point; limits input sample format to U8, S16, and S32.
409 32-bit floating-point; limits input sample format to FLT. (default)
411 64-bit floating-point; limits input sample format to DBL.
419 Halve the input audio volume:
423 volume=volume=-6.0206dB
427 Increase input audio power by 6 decibels using fixed-point precision:
429 volume=volume=6dB:precision=fixed
433 @c man end AUDIO FILTERS
435 @chapter Audio Sources
436 @c man begin AUDIO SOURCES
438 Below is a description of the currently available audio sources.
442 Null audio source, never return audio frames. It is mainly useful as a
443 template and to be employed in analysis / debugging tools.
445 It accepts as optional parameter a string of the form
446 @var{sample_rate}:@var{channel_layout}.
448 @var{sample_rate} specify the sample rate, and defaults to 44100.
450 @var{channel_layout} specify the channel layout, and can be either an
451 integer or a string representing a channel layout. The default value
452 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
454 Check the channel_layout_map definition in
455 @file{libavutil/channel_layout.c} for the mapping between strings and
456 channel layout values.
458 Follow some examples:
460 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
468 Buffer audio frames, and make them available to the filter chain.
470 This source is not intended to be part of user-supplied graph descriptions but
471 for insertion by calling programs through the interface defined in
472 @file{libavfilter/buffersrc.h}.
474 It accepts the following named parameters:
478 Timebase which will be used for timestamps of submitted frames. It must be
479 either a floating-point number or in @var{numerator}/@var{denominator} form.
485 Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
488 Channel layout of the audio data, in the form that can be accepted by
489 @code{av_get_channel_layout()}.
492 All the parameters need to be explicitly defined.
494 @c man end AUDIO SOURCES
497 @c man begin AUDIO SINKS
499 Below is a description of the currently available audio sinks.
503 Null audio sink, do absolutely nothing with the input audio. It is
504 mainly useful as a template and to be employed in analysis / debugging
508 This sink is intended for programmatic use. Frames that arrive on this sink can
509 be retrieved by the calling program using the interface defined in
510 @file{libavfilter/buffersink.h}.
512 This filter accepts no parameters.
514 @c man end AUDIO SINKS
516 @chapter Video Filters
517 @c man begin VIDEO FILTERS
519 When you configure your Libav build, you can disable any of the
520 existing filters using --disable-filters.
521 The configure output will show the video filters included in your
524 Below is a description of the currently available video filters.
528 Detect frames that are (almost) completely black. Can be useful to
529 detect chapter transitions or commercials. Output lines consist of
530 the frame number of the detected frame, the percentage of blackness,
531 the position in the file if known or -1 and the timestamp in seconds.
533 In order to display the output lines, you need to set the loglevel at
534 least to the AV_LOG_INFO value.
536 The filter accepts the following options:
541 The percentage of the pixels that have to be below the threshold, defaults to
545 Threshold below which a pixel value is considered black, defaults to 32.
551 Apply boxblur algorithm to the input video.
553 This filter accepts the following options:
566 Chroma and alpha parameters are optional, if not specified they default
567 to the corresponding values set for @var{luma_radius} and
570 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
571 the radius in pixels of the box used for blurring the corresponding
572 input plane. They are expressions, and can contain the following
576 the input width and height in pixels
579 the input chroma image width and height in pixels
582 horizontal and vertical chroma subsample values. For example for the
583 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
586 The radius must be a non-negative number, and must not be greater than
587 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
588 and of @code{min(cw,ch)/2} for the chroma planes.
590 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
591 how many times the boxblur filter is applied to the corresponding
594 Some examples follow:
599 Apply a boxblur filter with luma, chroma, and alpha radius
602 boxblur=luma_radius=2:luma_power=1
606 Set luma radius to 2, alpha and chroma radius to 0
612 Set luma and chroma radius to a fraction of the video dimension
614 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
621 Copy the input source unchanged to the output. Mainly useful for
626 Crop the input video to given dimensions.
628 This filter accepts the following options:
633 Width of the output video.
636 Height of the output video.
639 Horizontal position, in the input video, of the left edge of the output video.
642 Vertical position, in the input video, of the top edge of the output video.
646 The parameters are expressions containing the following constants:
650 the corresponding mathematical approximated values for e
651 (euler number), pi (greek PI), PHI (golden ratio)
654 the computed values for @var{x} and @var{y}. They are evaluated for
658 the input width and height
661 same as @var{in_w} and @var{in_h}
664 the output (cropped) width and height
667 same as @var{out_w} and @var{out_h}
670 the number of input frame, starting from 0
673 timestamp expressed in seconds, NAN if the input timestamp is unknown
677 The @var{out_w} and @var{out_h} parameters specify the expressions for
678 the width and height of the output (cropped) video. They are
679 evaluated just at the configuration of the filter.
681 The default value of @var{out_w} is "in_w", and the default value of
682 @var{out_h} is "in_h".
684 The expression for @var{out_w} may depend on the value of @var{out_h},
685 and the expression for @var{out_h} may depend on @var{out_w}, but they
686 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
687 evaluated after @var{out_w} and @var{out_h}.
689 The @var{x} and @var{y} parameters specify the expressions for the
690 position of the top-left corner of the output (non-cropped) area. They
691 are evaluated for each frame. If the evaluated value is not valid, it
692 is approximated to the nearest valid value.
694 The default value of @var{x} is "(in_w-out_w)/2", and the default
695 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
696 the center of the input image.
698 The expression for @var{x} may depend on @var{y}, and the expression
699 for @var{y} may depend on @var{x}.
701 Follow some examples:
703 # crop the central input area with size 100x100
704 crop=out_w=100:out_h=100
706 # crop the central input area with size 2/3 of the input video
707 "crop=out_w=2/3*in_w:out_h=2/3*in_h"
709 # crop the input video central square
712 # delimit the rectangle with the top-left corner placed at position
713 # 100:100 and the right-bottom corner corresponding to the right-bottom
714 # corner of the input image.
715 crop=out_w=in_w-100:out_h=in_h-100:x=100:y=100
717 # crop 10 pixels from the left and right borders, and 20 pixels from
718 # the top and bottom borders
719 "crop=out_w=in_w-2*10:out_h=in_h-2*20"
721 # keep only the bottom right quarter of the input image
722 "crop=out_w=in_w/2:out_h=in_h/2:x=in_w/2:y=in_h/2"
724 # crop height for getting Greek harmony
725 "crop=out_w=in_w:out_h=1/PHI*in_w"
728 "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)"
730 # erratic camera effect depending on timestamp
731 "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)"
733 # set x depending on the value of y
734 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
739 Auto-detect crop size.
741 Calculate necessary cropping parameters and prints the recommended
742 parameters through the logging system. The detected dimensions
743 correspond to the non-black area of the input video.
745 This filter accepts the following options:
750 Threshold, which can be optionally specified from nothing (0) to
751 everything (255), defaults to 24.
754 Value which the width/height should be divisible by, defaults to
755 16. The offset is automatically adjusted to center the video. Use 2 to
756 get only even dimensions (needed for 4:2:2 video). 16 is best when
757 encoding to most video codecs.
760 Counter that determines after how many frames cropdetect will reset
761 the previously detected largest video area and start over to detect
762 the current optimal crop area. Defaults to 0.
764 This can be useful when channel logos distort the video area. 0
765 indicates never reset and return the largest area encountered during
771 Suppress a TV station logo by a simple interpolation of the surrounding
772 pixels. Just set a rectangle covering the logo and watch it disappear
773 (and sometimes something even uglier appear - your mileage may vary).
775 This filter accepts the following options:
779 Specify the top left corner coordinates of the logo. They must be
783 Specify the width and height of the logo to clear. They must be
787 Specify the thickness of the fuzzy edge of the rectangle (added to
788 @var{w} and @var{h}). The default value is 4.
791 When set to 1, a green rectangle is drawn on the screen to simplify
792 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
793 @var{band} is set to 4. The default value is 0.
797 Some examples follow.
802 Set a rectangle covering the area with top left corner coordinates 0,0
803 and size 100x77, setting a band of size 10:
805 delogo=x=0:y=0:w=100:h=77:band=10
812 Draw a colored box on the input image.
814 This filter accepts the following options:
819 Specify the top left corner coordinates of the box. Default to 0.
822 Specify the width and height of the box, if 0 they are interpreted as
823 the input width and height. Default to 0.
826 Specify the color of the box to write, it can be the name of a color
827 (case insensitive match) or a 0xRRGGBB[AA] sequence.
830 Follow some examples:
832 # draw a black box around the edge of the input image
835 # draw a box with color red and an opacity of 50%
836 drawbox=x=10:y=20:width=200:height=60:color=red@@0.5"
841 Draw text string or text from specified file on top of video using the
844 To enable compilation of this filter you need to configure Libav with
845 @code{--enable-libfreetype}.
847 The filter also recognizes strftime() sequences in the provided text
848 and expands them accordingly. Check the documentation of strftime().
850 The description of the accepted parameters follows.
855 The font file to be used for drawing text. Path must be included.
856 This parameter is mandatory.
859 The text string to be drawn. The text must be a sequence of UTF-8
861 This parameter is mandatory if no file is specified with the parameter
865 A text file containing text to be drawn. The text must be a sequence
866 of UTF-8 encoded characters.
868 This parameter is mandatory if no text string is specified with the
869 parameter @var{text}.
871 If both text and textfile are specified, an error is thrown.
874 The offsets where text will be drawn within the video frame.
875 Relative to the top/left border of the output image.
876 They accept expressions similar to the @ref{overlay} filter:
880 the computed values for @var{x} and @var{y}. They are evaluated for
884 main input width and height
887 same as @var{main_w} and @var{main_h}
890 rendered text width and height
893 same as @var{text_w} and @var{text_h}
896 the number of frames processed, starting from 0
899 timestamp expressed in seconds, NAN if the input timestamp is unknown
903 The default value of @var{x} and @var{y} is 0.
906 The font size to be used for drawing text.
907 The default value of @var{fontsize} is 16.
910 The color to be used for drawing fonts.
911 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
912 (e.g. "0xff000033"), possibly followed by an alpha specifier.
913 The default value of @var{fontcolor} is "black".
916 The color to be used for drawing box around text.
917 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
918 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
919 The default value of @var{boxcolor} is "white".
922 Used to draw a box around text using background color.
923 Value should be either 1 (enable) or 0 (disable).
924 The default value of @var{box} is 0.
926 @item shadowx, shadowy
927 The x and y offsets for the text shadow position with respect to the
928 position of the text. They can be either positive or negative
929 values. Default value for both is "0".
932 The color to be used for drawing a shadow behind the drawn text. It
933 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
934 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
935 The default value of @var{shadowcolor} is "black".
938 Flags to be used for loading the fonts.
940 The flags map the corresponding flags supported by libfreetype, and are
941 a combination of the following values:
948 @item vertical_layout
952 @item ignore_global_advance_width
954 @item ignore_transform
961 Default value is "render".
963 For more information consult the documentation for the FT_LOAD_*
967 The size in number of spaces to use for rendering the tab.
971 If true, check and fix text coords to avoid clipping.
974 For example the command:
976 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
979 will draw "Test Text" with font FreeSerif, using the default values
980 for the optional parameters.
984 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
985 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
988 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
989 and y=50 (counting from the top-left corner of the screen), text is
990 yellow with a red box around it. Both the text and the box have an
993 Note that the double quotes are not necessary if spaces are not used
994 within the parameter list.
996 For more information about libfreetype, check:
997 @url{http://www.freetype.org/}.
1001 Apply fade-in/out effect to input video.
1003 This filter accepts the following options:
1008 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
1012 The number of the start frame for starting to apply the fade effect.
1015 The number of frames for which the fade effect has to last. At the end of the
1016 fade-in effect the output video will have the same intensity as the input video,
1017 at the end of the fade-out transition the output video will be completely black.
1021 A few usage examples follow, usable too as test scenarios.
1023 # fade in first 30 frames of video
1024 fade=type=in:nb_frames=30
1026 # fade out last 45 frames of a 200-frame video
1027 fade=type=out:start_frame=155:nb_frames=45
1029 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
1030 fade=type=in:start_frame=0:nb_frames=25, fade=type=out:start_frame=975:nb_frames=25
1032 # make first 5 frames black, then fade in from frame 5-24
1033 fade=type=in:start_frame=5:nb_frames=20
1038 Transform the field order of the input video.
1040 This filter accepts the following options:
1045 Output field order. Valid values are @var{tff} for top field first or @var{bff}
1046 for bottom field first.
1049 Default value is "tff".
1051 Transformation is achieved by shifting the picture content up or down
1052 by one line, and filling the remaining line with appropriate picture content.
1053 This method is consistent with most broadcast field order converters.
1055 If the input video is not flagged as being interlaced, or it is already
1056 flagged as being of the required output field order then this filter does
1057 not alter the incoming video.
1059 This filter is very useful when converting to or from PAL DV material,
1060 which is bottom field first.
1064 ./avconv -i in.vob -vf "fieldorder=order=bff" out.dv
1069 Buffer input images and send them when they are requested.
1071 This filter is mainly useful when auto-inserted by the libavfilter
1074 The filter does not take parameters.
1078 Convert the input video to one of the specified pixel formats.
1079 Libavfilter will try to pick one that is supported for the input to
1082 This filter accepts the following parameters:
1086 A '|'-separated list of pixel format names, for example
1087 "pix_fmts=yuv420p|monow|rgb24".
1091 Some examples follow:
1093 # convert the input video to the format "yuv420p"
1094 format=pix_fmts=yuv420p
1096 # convert the input video to any of the formats in the list
1097 format=pix_fmts=yuv420p|yuv444p|yuv410p
1102 Convert the video to specified constant framerate by duplicating or dropping
1103 frames as necessary.
1105 This filter accepts the following named parameters:
1109 Desired output framerate.
1116 Apply a frei0r effect to the input video.
1118 To enable compilation of this filter you need to install the frei0r
1119 header and configure Libav with --enable-frei0r.
1121 This filter accepts the following options:
1126 The name to the frei0r effect to load. If the environment variable
1127 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
1128 directories specified by the colon separated list in @env{FREIOR_PATH},
1129 otherwise in the standard frei0r paths, which are in this order:
1130 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
1131 @file{/usr/lib/frei0r-1/}.
1134 A '|'-separated list of parameters to pass to the frei0r effect.
1138 A frei0r effect parameter can be a boolean (whose values are specified
1139 with "y" and "n"), a double, a color (specified by the syntax
1140 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
1141 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
1142 description), a position (specified by the syntax @var{X}/@var{Y},
1143 @var{X} and @var{Y} being float numbers) and a string.
1145 The number and kind of parameters depend on the loaded effect. If an
1146 effect parameter is not specified the default value is set.
1148 Some examples follow:
1150 # apply the distort0r effect, set the first two double parameters
1151 frei0r=filter_name=distort0r:filter_params=0.5|0.01
1153 # apply the colordistance effect, takes a color as first parameter
1154 frei0r=colordistance:0.2/0.3/0.4
1155 frei0r=colordistance:violet
1156 frei0r=colordistance:0x112233
1158 # apply the perspective effect, specify the top left and top right
1160 frei0r=perspective:0.2/0.2|0.8/0.2
1163 For more information see:
1164 @url{http://piksel.org/frei0r}
1168 Fix the banding artifacts that are sometimes introduced into nearly flat
1169 regions by truncation to 8bit colordepth.
1170 Interpolate the gradients that should go where the bands are, and
1173 This filter is designed for playback only. Do not use it prior to
1174 lossy compression, because compression tends to lose the dither and
1175 bring back the bands.
1177 This filter accepts the following options:
1182 The maximum amount by which the filter will change any one pixel. Also the
1183 threshold for detecting nearly flat regions. Acceptable values range from .51 to
1184 64, default value is 1.2, out-of-range values will be clipped to the valid
1188 The neighborhood to fit the gradient to. A larger radius makes for smoother
1189 gradients, but also prevents the filter from modifying the pixels near detailed
1190 regions. Acceptable values are 8-32, default value is 16, out-of-range values
1191 will be clipped to the valid range.
1196 # default parameters
1197 gradfun=strength=1.2:radius=16
1205 Flip the input video horizontally.
1207 For example to horizontally flip the input video with @command{avconv}:
1209 avconv -i in.avi -vf "hflip" out.avi
1214 High precision/quality 3d denoise filter. This filter aims to reduce
1215 image noise producing smooth images and making still images really
1216 still. It should enhance compressibility.
1218 It accepts the following optional parameters:
1222 a non-negative float number which specifies spatial luma strength,
1225 @item chroma_spatial
1226 a non-negative float number which specifies spatial chroma strength,
1227 defaults to 3.0*@var{luma_spatial}/4.0
1230 a float number which specifies luma temporal strength, defaults to
1231 6.0*@var{luma_spatial}/4.0
1234 a float number which specifies chroma temporal strength, defaults to
1235 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
1238 @section lut, lutrgb, lutyuv
1240 Compute a look-up table for binding each pixel component input value
1241 to an output value, and apply it to input video.
1243 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
1244 to an RGB input video.
1246 These filters accept the following options:
1248 @item @var{c0} (first pixel component)
1249 @item @var{c1} (second pixel component)
1250 @item @var{c2} (third pixel component)
1251 @item @var{c3} (fourth pixel component, corresponds to the alpha component)
1253 @item @var{r} (red component)
1254 @item @var{g} (green component)
1255 @item @var{b} (blue component)
1256 @item @var{a} (alpha component)
1258 @item @var{y} (Y/luminance component)
1259 @item @var{u} (U/Cb component)
1260 @item @var{v} (V/Cr component)
1263 Each of them specifies the expression to use for computing the lookup table for
1264 the corresponding pixel component values.
1266 The exact component associated to each of the @var{c*} options depends on the
1269 The @var{lut} filter requires either YUV or RGB pixel formats in input,
1270 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
1272 The expressions can contain the following constants and functions:
1276 the corresponding mathematical approximated values for e
1277 (euler number), pi (greek PI), PHI (golden ratio)
1280 the input width and height
1283 input value for the pixel component
1286 the input value clipped in the @var{minval}-@var{maxval} range
1289 maximum value for the pixel component
1292 minimum value for the pixel component
1295 the negated value for the pixel component value clipped in the
1296 @var{minval}-@var{maxval} range , it corresponds to the expression
1297 "maxval-clipval+minval"
1300 the computed value in @var{val} clipped in the
1301 @var{minval}-@var{maxval} range
1303 @item gammaval(gamma)
1304 the computed gamma correction value of the pixel component value
1305 clipped in the @var{minval}-@var{maxval} range, corresponds to the
1307 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
1311 All expressions default to "val".
1313 Some examples follow:
1315 # negate input video
1316 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
1317 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
1319 # the above is the same as
1320 lutrgb="r=negval:g=negval:b=negval"
1321 lutyuv="y=negval:u=negval:v=negval"
1326 # remove chroma components, turns the video into a graytone image
1327 lutyuv="u=128:v=128"
1329 # apply a luma burning effect
1332 # remove green and blue components
1335 # set a constant alpha channel value on input
1336 format=rgba,lutrgb=a="maxval-minval/2"
1338 # correct luminance gamma by a 0.5 factor
1339 lutyuv=y=gammaval(0.5)
1346 This filter accepts an integer in input, if non-zero it negates the
1347 alpha component (if available). The default value in input is 0.
1351 Force libavfilter not to use any of the specified pixel formats for the
1352 input to the next filter.
1354 This filter accepts the following parameters:
1358 A '|'-separated list of pixel format names, for example
1359 "pix_fmts=yuv420p|monow|rgb24".
1363 Some examples follow:
1365 # force libavfilter to use a format different from "yuv420p" for the
1366 # input to the vflip filter
1367 noformat=pix_fmts=yuv420p,vflip
1369 # convert the input video to any of the formats not contained in the list
1370 noformat=yuv420p|yuv444p|yuv410p
1375 Pass the video source unchanged to the output.
1379 Apply video transform using libopencv.
1381 To enable this filter install libopencv library and headers and
1382 configure Libav with --enable-libopencv.
1384 This filter accepts the following parameters:
1389 The name of the libopencv filter to apply.
1392 The parameters to pass to the libopencv filter. If not specified the default
1397 Refer to the official libopencv documentation for more precise
1399 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1401 Follows the list of supported libopencv filters.
1406 Dilate an image by using a specific structuring element.
1407 This filter corresponds to the libopencv function @code{cvDilate}.
1409 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
1411 @var{struct_el} represents a structuring element, and has the syntax:
1412 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1414 @var{cols} and @var{rows} represent the number of columns and rows of
1415 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1416 point, and @var{shape} the shape for the structuring element, and
1417 can be one of the values "rect", "cross", "ellipse", "custom".
1419 If the value for @var{shape} is "custom", it must be followed by a
1420 string of the form "=@var{filename}". The file with name
1421 @var{filename} is assumed to represent a binary image, with each
1422 printable character corresponding to a bright pixel. When a custom
1423 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1424 or columns and rows of the read file are assumed instead.
1426 The default value for @var{struct_el} is "3x3+0x0/rect".
1428 @var{nb_iterations} specifies the number of times the transform is
1429 applied to the image, and defaults to 1.
1431 Follow some example:
1433 # use the default values
1436 # dilate using a structuring element with a 5x5 cross, iterate two times
1437 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
1439 # read the shape from the file diamond.shape, iterate two times
1440 # the file diamond.shape may contain a pattern of characters like this:
1446 # the specified cols and rows are ignored (but not the anchor point coordinates)
1447 ocv=dilate:0x0+2x2/custom=diamond.shape|2
1452 Erode an image by using a specific structuring element.
1453 This filter corresponds to the libopencv function @code{cvErode}.
1455 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1456 with the same syntax and semantics as the @ref{dilate} filter.
1460 Smooth the input video.
1462 The filter takes the following parameters:
1463 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
1465 @var{type} is the type of smooth filter to apply, and can be one of
1466 the following values: "blur", "blur_no_scale", "median", "gaussian",
1467 "bilateral". The default value is "gaussian".
1469 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1470 parameters whose meanings depend on smooth type. @var{param1} and
1471 @var{param2} accept integer positive values or 0, @var{param3} and
1472 @var{param4} accept float values.
1474 The default value for @var{param1} is 3, the default value for the
1475 other parameters is 0.
1477 These parameters correspond to the parameters assigned to the
1478 libopencv function @code{cvSmooth}.
1483 Overlay one video on top of another.
1485 It takes two inputs and one output, the first input is the "main"
1486 video on which the second input is overlayed.
1488 This filter accepts the following parameters:
1493 The horizontal position of the left edge of the overlaid video on the main video.
1496 The vertical position of the top edge of the overlaid video on the main video.
1500 The parameters are expressions containing the following parameters:
1503 @item main_w, main_h
1504 main input width and height
1507 same as @var{main_w} and @var{main_h}
1509 @item overlay_w, overlay_h
1510 overlay input width and height
1513 same as @var{overlay_w} and @var{overlay_h}
1516 Be aware that frames are taken from each input video in timestamp
1517 order, hence, if their initial timestamps differ, it is a a good idea
1518 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1519 have them begin in the same zero timestamp, as it does the example for
1520 the @var{movie} filter.
1522 Follow some examples:
1524 # draw the overlay at 10 pixels from the bottom right
1525 # corner of the main video.
1526 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
1528 # insert a transparent PNG logo in the bottom left corner of the input
1529 avconv -i input -i logo -filter_complex 'overlay=x=10:y=main_h-overlay_h-10' output
1531 # insert 2 different transparent PNG logos (second logo on bottom
1533 avconv -i input -i logo1 -i logo2 -filter_complex
1534 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
1536 # add a transparent color layer on top of the main video,
1537 # WxH specifies the size of the main input to the overlay filter
1538 color=red@.3:WxH [over]; [in][over] overlay [out]
1541 You can chain together more overlays but the efficiency of such
1542 approach is yet to be tested.
1546 Add paddings to the input image, and places the original input at the
1547 given coordinates @var{x}, @var{y}.
1549 This filter accepts the following parameters:
1554 Specify the size of the output image with the paddings added. If the
1555 value for @var{width} or @var{height} is 0, the corresponding input size
1556 is used for the output.
1558 The @var{width} expression can reference the value set by the
1559 @var{height} expression, and vice versa.
1561 The default value of @var{width} and @var{height} is 0.
1565 Specify the offsets where to place the input image in the padded area
1566 with respect to the top/left border of the output image.
1568 The @var{x} expression can reference the value set by the @var{y}
1569 expression, and vice versa.
1571 The default value of @var{x} and @var{y} is 0.
1575 Specify the color of the padded area, it can be the name of a color
1576 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1578 The default value of @var{color} is "black".
1582 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1583 expressions containing the following constants:
1587 the corresponding mathematical approximated values for e
1588 (euler number), pi (greek PI), phi (golden ratio)
1591 the input video width and height
1594 same as @var{in_w} and @var{in_h}
1597 the output width and height, that is the size of the padded area as
1598 specified by the @var{width} and @var{height} expressions
1601 same as @var{out_w} and @var{out_h}
1604 x and y offsets as specified by the @var{x} and @var{y}
1605 expressions, or NAN if not yet specified
1608 input display aspect ratio, same as @var{iw} / @var{ih}
1611 horizontal and vertical chroma subsample values. For example for the
1612 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1615 Some examples follow:
1618 # Add paddings with color "violet" to the input video. Output video
1619 # size is 640x480, the top-left corner of the input video is placed at
1621 pad=width=640:height=480:x=0:y=40:color=violet
1623 # pad the input to get an output with dimensions increased bt 3/2,
1624 # and put the input video at the center of the padded area
1625 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1627 # pad the input to get a squared output with size equal to the maximum
1628 # value between the input width and height, and put the input video at
1629 # the center of the padded area
1630 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1632 # pad the input to get a final w/h ratio of 16:9
1633 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1635 # double output size and put the input video in the bottom-right
1636 # corner of the output padded area
1637 pad="2*iw:2*ih:ow-iw:oh-ih"
1640 @section pixdesctest
1642 Pixel format descriptor test filter, mainly useful for internal
1643 testing. The output video should be equal to the input video.
1647 format=monow, pixdesctest
1650 can be used to test the monowhite pixel format descriptor definition.
1654 Scale the input video and/or convert the image format.
1656 This filter accepts the following options:
1664 Output video height.
1668 The parameters @var{w} and @var{h} are expressions containing
1669 the following constants:
1673 the corresponding mathematical approximated values for e
1674 (euler number), pi (greek PI), phi (golden ratio)
1677 the input width and height
1680 same as @var{in_w} and @var{in_h}
1683 the output (cropped) width and height
1686 same as @var{out_w} and @var{out_h}
1689 input display aspect ratio, same as @var{iw} / @var{ih}
1692 input sample aspect ratio
1695 horizontal and vertical chroma subsample values. For example for the
1696 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1699 If the input image format is different from the format requested by
1700 the next filter, the scale filter will convert the input to the
1703 If the value for @var{w} or @var{h} is 0, the respective input
1704 size is used for the output.
1706 If the value for @var{w} or @var{h} is -1, the scale filter will use, for the
1707 respective output size, a value that maintains the aspect ratio of the input
1710 The default value of @var{w} and @var{h} is 0.
1712 Some examples follow:
1714 # scale the input video to a size of 200x100.
1717 # scale the input to 2x
1719 # the above is the same as
1722 # scale the input to half size
1725 # increase the width, and set the height to the same size
1728 # seek for Greek harmony
1732 # increase the height, and set the width to 3/2 of the height
1733 scale=w=3/2*oh:h=3/5*ih
1735 # increase the size, but make the size a multiple of the chroma
1736 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1738 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1739 scale=w='min(500\, iw*3/2):h=-1'
1743 Select frames to pass in output.
1745 This filter accepts the following options:
1750 An expression, which is evaluated for each input frame. If the expression is
1751 evaluated to a non-zero value, the frame is selected and passed to the output,
1752 otherwise it is discarded.
1756 The expression can contain the following constants:
1769 the sequential number of the filtered frame, starting from 0
1772 the sequential number of the selected frame, starting from 0
1774 @item prev_selected_n
1775 the sequential number of the last selected frame, NAN if undefined
1778 timebase of the input timestamps
1781 the PTS (Presentation TimeStamp) of the filtered video frame,
1782 expressed in @var{TB} units, NAN if undefined
1785 the PTS (Presentation TimeStamp) of the filtered video frame,
1786 expressed in seconds, NAN if undefined
1789 the PTS of the previously filtered video frame, NAN if undefined
1791 @item prev_selected_pts
1792 the PTS of the last previously filtered video frame, NAN if undefined
1794 @item prev_selected_t
1795 the PTS of the last previously selected video frame, NAN if undefined
1798 the PTS of the first video frame in the video, NAN if undefined
1801 the time of the first video frame in the video, NAN if undefined
1804 the type of the filtered frame, can assume one of the following
1816 @item interlace_type
1817 the frame interlace type, can assume one of the following values:
1820 the frame is progressive (not interlaced)
1822 the frame is top-field-first
1824 the frame is bottom-field-first
1828 1 if the filtered frame is a key-frame, 0 otherwise
1832 The default value of the select expression is "1".
1834 Some examples follow:
1837 # select all frames in input
1840 # the above is the same as:
1846 # select only I-frames
1847 select='expr=eq(pict_type\,I)'
1849 # select one frame every 100
1850 select='not(mod(n\,100))'
1852 # select only frames contained in the 10-20 time interval
1853 select='gte(t\,10)*lte(t\,20)'
1855 # select only I frames contained in the 10-20 time interval
1856 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1858 # select frames with a minimum distance of 10 seconds
1859 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1865 Set the Display Aspect Ratio for the filter output video.
1867 This is done by changing the specified Sample (aka Pixel) Aspect
1868 Ratio, according to the following equation:
1869 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1871 Keep in mind that this filter does not modify the pixel dimensions of
1872 the video frame. Also the display aspect ratio set by this filter may
1873 be changed by later filters in the filterchain, e.g. in case of
1874 scaling or if another "setdar" or a "setsar" filter is applied.
1876 This filter accepts the following options:
1881 Output display aspect ratio, as a rational or a decimal number.
1885 For example to change the display aspect ratio to 16:9, specify:
1888 # the above is equivalent to
1892 See also the @ref{setsar} filter documentation.
1896 Change the PTS (presentation timestamp) of the input video frames.
1898 This filter accepts the following options:
1903 The expression which is evaluated for each frame to construct its timestamp.
1907 The expression is evaluated through the eval API and can contain the following
1912 the presentation timestamp in input
1924 the count of the input frame, starting from 0.
1927 the PTS of the first video frame
1930 tell if the current frame is interlaced
1939 wallclock (RTC) time in microseconds
1942 wallclock (RTC) time at the start of the movie in microseconds
1946 Some examples follow:
1949 # start counting PTS from zero
1950 setpts=expr=PTS-STARTPTS
1961 # fixed rate 25 fps with some jitter
1962 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1964 # generate timestamps from a "live source" and rebase onto the current timebase
1965 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)"
1971 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1973 Note that as a consequence of the application of this filter, the
1974 output display aspect ratio will change according to the following
1976 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1978 Keep in mind that the sample aspect ratio set by this filter may be
1979 changed by later filters in the filterchain, e.g. if another "setsar"
1980 or a "setdar" filter is applied.
1982 This filter accepts the following options:
1987 Output sample aspect ratio, as a rational or decimal number.
1991 For example to change the sample aspect ratio to 10:11, specify:
1998 Set the timebase to use for the output frames timestamps.
1999 It is mainly useful for testing timebase configuration.
2001 This filter accepts the following options:
2006 The expression which is evaluated into the output timebase.
2010 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
2011 default timebase), and "intb" (the input timebase).
2013 The default value for the input is "intb".
2015 Follow some examples.
2018 # set the timebase to 1/25
2021 # set the timebase to 1/10
2024 #set the timebase to 1001/1000
2027 #set the timebase to 2*intb
2030 #set the default timebase value
2036 Show a line containing various information for each input video frame.
2037 The input video is not modified.
2039 The shown line contains a sequence of key/value pairs of the form
2040 @var{key}:@var{value}.
2042 A description of each shown parameter follows:
2046 sequential number of the input frame, starting from 0
2049 Presentation TimeStamp of the input frame, expressed as a number of
2050 time base units. The time base unit depends on the filter input pad.
2053 Presentation TimeStamp of the input frame, expressed as a number of
2057 position of the frame in the input stream, -1 if this information in
2058 unavailable and/or meaningless (for example in case of synthetic video)
2064 sample aspect ratio of the input frame, expressed in the form
2068 size of the input frame, expressed in the form
2069 @var{width}x@var{height}
2072 interlaced mode ("P" for "progressive", "T" for top field first, "B"
2073 for bottom field first)
2076 1 if the frame is a key frame, 0 otherwise
2079 picture type of the input frame ("I" for an I-frame, "P" for a
2080 P-frame, "B" for a B-frame, "?" for unknown type).
2081 Check also the documentation of the @code{AVPictureType} enum and of
2082 the @code{av_get_picture_type_char} function defined in
2083 @file{libavutil/avutil.h}.
2086 Adler-32 checksum of all the planes of the input frame
2088 @item plane_checksum
2089 Adler-32 checksum of each plane of the input frame, expressed in the form
2090 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
2095 Split input video into several identical outputs.
2097 The filter accepts a single parameter which specifies the number of outputs. If
2098 unspecified, it defaults to 2.
2102 avconv -i INPUT -filter_complex split=5 OUTPUT
2104 will create 5 copies of the input video.
2108 Transpose rows with columns in the input video and optionally flip it.
2110 This filter accepts the following options:
2115 The direction of the transpose.
2119 The direction can assume the following values:
2123 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
2131 Rotate by 90 degrees clockwise, that is:
2139 Rotate by 90 degrees counterclockwise, that is:
2147 Rotate by 90 degrees clockwise and vertically flip, that is:
2157 Sharpen or blur the input video.
2159 It accepts the following parameters:
2164 Set the luma matrix horizontal size. It can be an integer between 3
2165 and 13, default value is 5.
2168 Set the luma matrix vertical size. It can be an integer between 3
2169 and 13, default value is 5.
2172 Set the luma effect strength. It can be a float number between -2.0
2173 and 5.0, default value is 1.0.
2175 @item chroma_msize_x
2176 Set the chroma matrix horizontal size. It can be an integer between 3
2177 and 13, default value is 5.
2179 @item chroma_msize_y
2180 Set the chroma matrix vertical size. It can be an integer between 3
2181 and 13, default value is 5.
2184 Set the chroma effect strength. It can be a float number between -2.0
2185 and 5.0, default value is 0.0.
2189 Negative values for the amount will blur the input video, while positive
2190 values will sharpen. All parameters are optional and default to the
2191 equivalent of the string '5:5:1.0:5:5:0.0'.
2194 # Strong luma sharpen effect parameters
2195 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
2197 # Strong blur of both luma and chroma parameters
2198 unsharp=7:7:-2:7:7:-2
2200 # Use the default values with @command{avconv}
2201 ./avconv -i in.avi -vf "unsharp" out.mp4
2206 Flip the input video vertically.
2209 ./avconv -i in.avi -vf "vflip" out.avi
2214 Deinterlace the input video ("yadif" means "yet another deinterlacing
2217 This filter accepts the following options:
2222 The interlacing mode to adopt, accepts one of the following values:
2226 output 1 frame for each frame
2228 output 1 frame for each field
2230 like 0 but skips spatial interlacing check
2232 like 1 but skips spatial interlacing check
2238 The picture field parity assumed for the input interlaced video, accepts one of
2239 the following values:
2243 assume top field first
2245 assume bottom field first
2247 enable automatic detection
2250 Default value is -1.
2251 If interlacing is unknown or decoder does not export this information,
2252 top field first will be assumed.
2255 Whether deinterlacer should trust the interlaced flag and only deinterlace
2256 frames marked as interlaced
2260 deinterlace all frames
2262 only deinterlace frames marked as interlaced
2269 @c man end VIDEO FILTERS
2271 @chapter Video Sources
2272 @c man begin VIDEO SOURCES
2274 Below is a description of the currently available video sources.
2278 Buffer video frames, and make them available to the filter chain.
2280 This source is mainly intended for a programmatic use, in particular
2281 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
2283 This filter accepts the following parameters:
2294 Name of the input video pixel format.
2297 The time base used for input timestamps.
2300 Sample (pixel) aspect ratio of the input video.
2306 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
2309 will instruct the source to accept video frames with size 320x240 and
2310 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2311 square pixels (1:1 sample aspect ratio).
2315 Provide an uniformly colored input.
2317 It accepts the following parameters:
2322 Specify the color of the source. It can be the name of a color (case
2323 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2324 alpha specifier. The default value is "black".
2327 Specify the size of the sourced video, it may be a string of the form
2328 @var{width}x@var{height}, or the name of a size abbreviation. The
2329 default value is "320x240".
2332 Specify the frame rate of the sourced video, as the number of frames
2333 generated per second. It has to be a string in the format
2334 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2335 number or a valid video frame rate abbreviation. The default value is
2340 For example the following graph description will generate a red source
2341 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2342 frames per second, which will be overlayed over the source connected
2343 to the pad with identifier "in".
2346 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2351 Read a video stream from a movie container.
2353 Note that this source is a hack that bypasses the standard input path. It can be
2354 useful in applications that do not support arbitrary filter graphs, but its use
2355 is discouraged in those that do. Specifically in @command{avconv} this filter
2356 should never be used, the @option{-filter_complex} option fully replaces it.
2358 This filter accepts the following options:
2363 The name of the resource to read (not necessarily a file but also a device or a
2364 stream accessed through some protocol).
2366 @item format_name, f
2367 Specifies the format assumed for the movie to read, and can be either
2368 the name of a container or an input device. If not specified the
2369 format is guessed from @var{movie_name} or by probing.
2371 @item seek_point, sp
2372 Specifies the seek point in seconds, the frames will be output
2373 starting from this seek point, the parameter is evaluated with
2374 @code{av_strtod} so the numerical value may be suffixed by an IS
2375 postfix. Default value is "0".
2377 @item stream_index, si
2378 Specifies the index of the video stream to read. If the value is -1,
2379 the best suited video stream will be automatically selected. Default
2384 This filter allows to overlay a second video on top of main input of
2385 a filtergraph as shown in this graph:
2387 input -----------> deltapts0 --> overlay --> output
2390 movie --> scale--> deltapts1 -------+
2393 Some examples follow:
2395 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2396 # on top of the input labelled as "in".
2397 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2398 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2400 # read from a video4linux2 device, and overlay it on top of the input
2402 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2403 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2409 Null video source, never return images. It is mainly useful as a
2410 template and to be employed in analysis / debugging tools.
2412 It accepts as optional parameter a string of the form
2413 @var{width}:@var{height}:@var{timebase}.
2415 @var{width} and @var{height} specify the size of the configured
2416 source. The default values of @var{width} and @var{height} are
2417 respectively 352 and 288 (corresponding to the CIF size format).
2419 @var{timebase} specifies an arithmetic expression representing a
2420 timebase. The expression can contain the constants "PI", "E", "PHI",
2421 "AVTB" (the default timebase), and defaults to the value "AVTB".
2425 Provide a frei0r source.
2427 To enable compilation of this filter you need to install the frei0r
2428 header and configure Libav with --enable-frei0r.
2430 This source accepts the following options:
2435 The size of the video to generate, may be a string of the form
2436 @var{width}x@var{height} or a frame size abbreviation.
2439 Framerate of the generated video, may be a string of the form
2440 @var{num}/@var{den} or a frame rate abbreviation.
2443 The name to the frei0r source to load. For more information regarding frei0r and
2444 how to set the parameters read the section @ref{frei0r} in the description of
2448 A '|'-separated list of parameters to pass to the frei0r source.
2452 Some examples follow:
2454 # generate a frei0r partik0l source with size 200x200 and framerate 10
2455 # which is overlayed on the overlay filter main input
2456 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
2459 @section rgbtestsrc, testsrc
2461 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2462 detecting RGB vs BGR issues. You should see a red, green and blue
2463 stripe from top to bottom.
2465 The @code{testsrc} source generates a test video pattern, showing a
2466 color pattern, a scrolling gradient and a timestamp. This is mainly
2467 intended for testing purposes.
2469 The sources accept the following options:
2474 Specify the size of the sourced video, it may be a string of the form
2475 @var{width}x@var{height}, or the name of a size abbreviation. The
2476 default value is "320x240".
2479 Specify the frame rate of the sourced video, as the number of frames
2480 generated per second. It has to be a string in the format
2481 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2482 number or a valid video frame rate abbreviation. The default value is
2486 Set the sample aspect ratio of the sourced video.
2489 Set the video duration of the sourced video. The accepted syntax is:
2491 [-]HH[:MM[:SS[.m...]]]
2494 See also the function @code{av_parse_time()}.
2496 If not specified, or the expressed duration is negative, the video is
2497 supposed to be generated forever.
2500 For example the following:
2502 testsrc=duration=5.3:size=qcif:rate=10
2505 will generate a video with a duration of 5.3 seconds, with size
2506 176x144 and a framerate of 10 frames per second.
2508 @c man end VIDEO SOURCES
2510 @chapter Video Sinks
2511 @c man begin VIDEO SINKS
2513 Below is a description of the currently available video sinks.
2517 Buffer video frames, and make them available to the end of the filter
2520 This sink is intended for a programmatic use through the interface defined in
2521 @file{libavfilter/buffersink.h}.
2525 Null video sink, do absolutely nothing with the input video. It is
2526 mainly useful as a template and to be employed in analysis / debugging
2529 @c man end VIDEO SINKS