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/avfiltergraph.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 comma-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 comma-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 in input a ":"-separated list of options, which
1247 specify the expressions used for computing the lookup table for the
1248 corresponding pixel component values.
1250 The @var{lut} filter requires either YUV or RGB pixel formats in
1251 input, and accepts the options:
1253 @item @var{c0} (first pixel component)
1254 @item @var{c1} (second pixel component)
1255 @item @var{c2} (third pixel component)
1256 @item @var{c3} (fourth pixel component, corresponds to the alpha component)
1259 The exact component associated to each option depends on the format in
1262 The @var{lutrgb} filter requires RGB pixel formats in input, and
1263 accepts the options:
1265 @item @var{r} (red component)
1266 @item @var{g} (green component)
1267 @item @var{b} (blue component)
1268 @item @var{a} (alpha component)
1271 The @var{lutyuv} filter requires YUV pixel formats in input, and
1272 accepts the options:
1274 @item @var{y} (Y/luminance component)
1275 @item @var{u} (U/Cb component)
1276 @item @var{v} (V/Cr component)
1277 @item @var{a} (alpha component)
1280 The expressions can contain the following constants and functions:
1284 the corresponding mathematical approximated values for e
1285 (euler number), pi (greek PI), PHI (golden ratio)
1288 the input width and height
1291 input value for the pixel component
1294 the input value clipped in the @var{minval}-@var{maxval} range
1297 maximum value for the pixel component
1300 minimum value for the pixel component
1303 the negated value for the pixel component value clipped in the
1304 @var{minval}-@var{maxval} range , it corresponds to the expression
1305 "maxval-clipval+minval"
1308 the computed value in @var{val} clipped in the
1309 @var{minval}-@var{maxval} range
1311 @item gammaval(gamma)
1312 the computed gamma correction value of the pixel component value
1313 clipped in the @var{minval}-@var{maxval} range, corresponds to the
1315 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
1319 All expressions default to "val".
1321 Some examples follow:
1323 # negate input video
1324 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
1325 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
1327 # the above is the same as
1328 lutrgb="r=negval:g=negval:b=negval"
1329 lutyuv="y=negval:u=negval:v=negval"
1334 # remove chroma components, turns the video into a graytone image
1335 lutyuv="u=128:v=128"
1337 # apply a luma burning effect
1340 # remove green and blue components
1343 # set a constant alpha channel value on input
1344 format=rgba,lutrgb=a="maxval-minval/2"
1346 # correct luminance gamma by a 0.5 factor
1347 lutyuv=y=gammaval(0.5)
1354 This filter accepts an integer in input, if non-zero it negates the
1355 alpha component (if available). The default value in input is 0.
1359 Force libavfilter not to use any of the specified pixel formats for the
1360 input to the next filter.
1362 This filter accepts the following parameters:
1366 A '|'-separated list of pixel format names, for example
1367 "pix_fmts=yuv420p|monow|rgb24".
1371 Some examples follow:
1373 # force libavfilter to use a format different from "yuv420p" for the
1374 # input to the vflip filter
1375 noformat=pix_fmts=yuv420p,vflip
1377 # convert the input video to any of the formats not contained in the list
1378 noformat=yuv420p|yuv444p|yuv410p
1383 Pass the video source unchanged to the output.
1387 Apply video transform using libopencv.
1389 To enable this filter install libopencv library and headers and
1390 configure Libav with --enable-libopencv.
1392 This filter accepts the following parameters:
1397 The name of the libopencv filter to apply.
1400 The parameters to pass to the libopencv filter. If not specified the default
1405 Refer to the official libopencv documentation for more precise
1407 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1409 Follows the list of supported libopencv filters.
1414 Dilate an image by using a specific structuring element.
1415 This filter corresponds to the libopencv function @code{cvDilate}.
1417 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
1419 @var{struct_el} represents a structuring element, and has the syntax:
1420 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1422 @var{cols} and @var{rows} represent the number of columns and rows of
1423 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1424 point, and @var{shape} the shape for the structuring element, and
1425 can be one of the values "rect", "cross", "ellipse", "custom".
1427 If the value for @var{shape} is "custom", it must be followed by a
1428 string of the form "=@var{filename}". The file with name
1429 @var{filename} is assumed to represent a binary image, with each
1430 printable character corresponding to a bright pixel. When a custom
1431 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1432 or columns and rows of the read file are assumed instead.
1434 The default value for @var{struct_el} is "3x3+0x0/rect".
1436 @var{nb_iterations} specifies the number of times the transform is
1437 applied to the image, and defaults to 1.
1439 Follow some example:
1441 # use the default values
1444 # dilate using a structuring element with a 5x5 cross, iterate two times
1445 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
1447 # read the shape from the file diamond.shape, iterate two times
1448 # the file diamond.shape may contain a pattern of characters like this:
1454 # the specified cols and rows are ignored (but not the anchor point coordinates)
1455 ocv=dilate:0x0+2x2/custom=diamond.shape|2
1460 Erode an image by using a specific structuring element.
1461 This filter corresponds to the libopencv function @code{cvErode}.
1463 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1464 with the same syntax and semantics as the @ref{dilate} filter.
1468 Smooth the input video.
1470 The filter takes the following parameters:
1471 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
1473 @var{type} is the type of smooth filter to apply, and can be one of
1474 the following values: "blur", "blur_no_scale", "median", "gaussian",
1475 "bilateral". The default value is "gaussian".
1477 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1478 parameters whose meanings depend on smooth type. @var{param1} and
1479 @var{param2} accept integer positive values or 0, @var{param3} and
1480 @var{param4} accept float values.
1482 The default value for @var{param1} is 3, the default value for the
1483 other parameters is 0.
1485 These parameters correspond to the parameters assigned to the
1486 libopencv function @code{cvSmooth}.
1491 Overlay one video on top of another.
1493 It takes two inputs and one output, the first input is the "main"
1494 video on which the second input is overlayed.
1496 It accepts the parameters: @var{x}:@var{y}.
1498 @var{x} is the x coordinate of the overlayed video on the main video,
1499 @var{y} is the y coordinate. The parameters are expressions containing
1500 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=main_w-overlay_w-10: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=10: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=10:H-h-10,overlay=W-w-10: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 It accepts the following parameters:
1550 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1552 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1553 expressions containing the following constants:
1557 the corresponding mathematical approximated values for e
1558 (euler number), pi (greek PI), phi (golden ratio)
1561 the input video width and height
1564 same as @var{in_w} and @var{in_h}
1567 the output width and height, that is the size of the padded area as
1568 specified by the @var{width} and @var{height} expressions
1571 same as @var{out_w} and @var{out_h}
1574 x and y offsets as specified by the @var{x} and @var{y}
1575 expressions, or NAN if not yet specified
1578 input display aspect ratio, same as @var{iw} / @var{ih}
1581 horizontal and vertical chroma subsample values. For example for the
1582 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1585 Follows the description of the accepted parameters.
1590 Specify the size of the output image with the paddings added. If the
1591 value for @var{width} or @var{height} is 0, the corresponding input size
1592 is used for the output.
1594 The @var{width} expression can reference the value set by the
1595 @var{height} expression, and vice versa.
1597 The default value of @var{width} and @var{height} is 0.
1601 Specify the offsets where to place the input image in the padded area
1602 with respect to the top/left border of the output image.
1604 The @var{x} expression can reference the value set by the @var{y}
1605 expression, and vice versa.
1607 The default value of @var{x} and @var{y} is 0.
1611 Specify the color of the padded area, it can be the name of a color
1612 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1614 The default value of @var{color} is "black".
1618 Some examples follow:
1621 # Add paddings with color "violet" to the input video. Output video
1622 # size is 640x480, the top-left corner of the input video is placed at
1624 pad=640:480:0:40:violet
1626 # pad the input to get an output with dimensions increased bt 3/2,
1627 # and put the input video at the center of the padded area
1628 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1630 # pad the input to get a squared output with size equal to the maximum
1631 # value between the input width and height, and put the input video at
1632 # the center of the padded area
1633 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1635 # pad the input to get a final w/h ratio of 16:9
1636 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1638 # double output size and put the input video in the bottom-right
1639 # corner of the output padded area
1640 pad="2*iw:2*ih:ow-iw:oh-ih"
1643 @section pixdesctest
1645 Pixel format descriptor test filter, mainly useful for internal
1646 testing. The output video should be equal to the input video.
1650 format=monow, pixdesctest
1653 can be used to test the monowhite pixel format descriptor definition.
1657 Scale the input video and/or convert the image format.
1659 This filter accepts the following options:
1667 Output video height.
1671 The parameters @var{w} and @var{h} are expressions containing
1672 the following constants:
1676 the corresponding mathematical approximated values for e
1677 (euler number), pi (greek PI), phi (golden ratio)
1680 the input width and height
1683 same as @var{in_w} and @var{in_h}
1686 the output (cropped) width and height
1689 same as @var{out_w} and @var{out_h}
1692 input display aspect ratio, same as @var{iw} / @var{ih}
1695 input sample aspect ratio
1698 horizontal and vertical chroma subsample values. For example for the
1699 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1702 If the input image format is different from the format requested by
1703 the next filter, the scale filter will convert the input to the
1706 If the value for @var{w} or @var{h} is 0, the respective input
1707 size is used for the output.
1709 If the value for @var{w} or @var{h} is -1, the scale filter will use, for the
1710 respective output size, a value that maintains the aspect ratio of the input
1713 The default value of @var{w} and @var{h} is 0.
1715 Some examples follow:
1717 # scale the input video to a size of 200x100.
1720 # scale the input to 2x
1722 # the above is the same as
1725 # scale the input to half size
1728 # increase the width, and set the height to the same size
1731 # seek for Greek harmony
1735 # increase the height, and set the width to 3/2 of the height
1736 scale=w=3/2*oh:h=3/5*ih
1738 # increase the size, but make the size a multiple of the chroma
1739 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1741 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1742 scale=w='min(500\, iw*3/2):h=-1'
1746 Select frames to pass in output.
1748 It accepts in input an expression, which is evaluated for each input
1749 frame. If the expression is evaluated to a non-zero value, the frame
1750 is selected and passed to the output, otherwise it is discarded.
1752 The expression can contain the following constants:
1765 the sequential number of the filtered frame, starting from 0
1768 the sequential number of the selected frame, starting from 0
1770 @item prev_selected_n
1771 the sequential number of the last selected frame, NAN if undefined
1774 timebase of the input timestamps
1777 the PTS (Presentation TimeStamp) of the filtered video frame,
1778 expressed in @var{TB} units, NAN if undefined
1781 the PTS (Presentation TimeStamp) of the filtered video frame,
1782 expressed in seconds, NAN if undefined
1785 the PTS of the previously filtered video frame, NAN if undefined
1787 @item prev_selected_pts
1788 the PTS of the last previously filtered video frame, NAN if undefined
1790 @item prev_selected_t
1791 the PTS of the last previously selected video frame, NAN if undefined
1794 the PTS of the first video frame in the video, NAN if undefined
1797 the time of the first video frame in the video, NAN if undefined
1800 the type of the filtered frame, can assume one of the following
1812 @item interlace_type
1813 the frame interlace type, can assume one of the following values:
1816 the frame is progressive (not interlaced)
1818 the frame is top-field-first
1820 the frame is bottom-field-first
1824 1 if the filtered frame is a key-frame, 0 otherwise
1828 The default value of the select expression is "1".
1830 Some examples follow:
1833 # select all frames in input
1836 # the above is the same as:
1842 # select only I-frames
1843 select='eq(pict_type\,I)'
1845 # select one frame every 100
1846 select='not(mod(n\,100))'
1848 # select only frames contained in the 10-20 time interval
1849 select='gte(t\,10)*lte(t\,20)'
1851 # select only I frames contained in the 10-20 time interval
1852 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1854 # select frames with a minimum distance of 10 seconds
1855 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1861 Set the Display Aspect Ratio for the filter output video.
1863 This is done by changing the specified Sample (aka Pixel) Aspect
1864 Ratio, according to the following equation:
1865 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1867 Keep in mind that this filter does not modify the pixel dimensions of
1868 the video frame. Also the display aspect ratio set by this filter may
1869 be changed by later filters in the filterchain, e.g. in case of
1870 scaling or if another "setdar" or a "setsar" filter is applied.
1872 This filter accepts the following options:
1877 Output display aspect ratio, as a rational or a decimal number.
1881 For example to change the display aspect ratio to 16:9, specify:
1884 # the above is equivalent to
1888 See also the @ref{setsar} filter documentation.
1892 Change the PTS (presentation timestamp) of the input video frames.
1894 Accept in input an expression evaluated through the eval API, which
1895 can contain the following constants:
1899 the presentation timestamp in input
1911 the count of the input frame, starting from 0.
1914 the PTS of the first video frame
1917 tell if the current frame is interlaced
1926 wallclock (RTC) time in microseconds
1929 wallclock (RTC) time at the start of the movie in microseconds
1933 Some examples follow:
1936 # start counting PTS from zero
1948 # fixed rate 25 fps with some jitter
1949 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1951 # generate timestamps from a "live source" and rebase onto the current timebase
1952 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)"
1958 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1960 Note that as a consequence of the application of this filter, the
1961 output display aspect ratio will change according to the following
1963 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1965 Keep in mind that the sample aspect ratio set by this filter may be
1966 changed by later filters in the filterchain, e.g. if another "setsar"
1967 or a "setdar" filter is applied.
1969 This filter accepts the following options:
1974 Output sample aspect ratio, as a rational or decimal number.
1978 For example to change the sample aspect ratio to 10:11, specify:
1985 Set the timebase to use for the output frames timestamps.
1986 It is mainly useful for testing timebase configuration.
1988 It accepts in input an arithmetic expression representing a rational.
1989 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1990 default timebase), and "intb" (the input timebase).
1992 The default value for the input is "intb".
1994 Follow some examples.
1997 # set the timebase to 1/25
2000 # set the timebase to 1/10
2003 #set the timebase to 1001/1000
2006 #set the timebase to 2*intb
2009 #set the default timebase value
2015 Show a line containing various information for each input video frame.
2016 The input video is not modified.
2018 The shown line contains a sequence of key/value pairs of the form
2019 @var{key}:@var{value}.
2021 A description of each shown parameter follows:
2025 sequential number of the input frame, starting from 0
2028 Presentation TimeStamp of the input frame, expressed as a number of
2029 time base units. The time base unit depends on the filter input pad.
2032 Presentation TimeStamp of the input frame, expressed as a number of
2036 position of the frame in the input stream, -1 if this information in
2037 unavailable and/or meaningless (for example in case of synthetic video)
2043 sample aspect ratio of the input frame, expressed in the form
2047 size of the input frame, expressed in the form
2048 @var{width}x@var{height}
2051 interlaced mode ("P" for "progressive", "T" for top field first, "B"
2052 for bottom field first)
2055 1 if the frame is a key frame, 0 otherwise
2058 picture type of the input frame ("I" for an I-frame, "P" for a
2059 P-frame, "B" for a B-frame, "?" for unknown type).
2060 Check also the documentation of the @code{AVPictureType} enum and of
2061 the @code{av_get_picture_type_char} function defined in
2062 @file{libavutil/avutil.h}.
2065 Adler-32 checksum of all the planes of the input frame
2067 @item plane_checksum
2068 Adler-32 checksum of each plane of the input frame, expressed in the form
2069 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
2074 Split input video into several identical outputs.
2076 The filter accepts a single parameter which specifies the number of outputs. If
2077 unspecified, it defaults to 2.
2081 avconv -i INPUT -filter_complex split=5 OUTPUT
2083 will create 5 copies of the input video.
2087 Transpose rows with columns in the input video and optionally flip it.
2089 It accepts a parameter representing an integer, which can assume the
2094 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
2102 Rotate by 90 degrees clockwise, that is:
2110 Rotate by 90 degrees counterclockwise, that is:
2118 Rotate by 90 degrees clockwise and vertically flip, that is:
2128 Sharpen or blur the input video.
2130 It accepts the following parameters:
2131 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
2133 Negative values for the amount will blur the input video, while positive
2134 values will sharpen. All parameters are optional and default to the
2135 equivalent of the string '5:5:1.0:5:5:0.0'.
2140 Set the luma matrix horizontal size. It can be an integer between 3
2141 and 13, default value is 5.
2144 Set the luma matrix vertical size. It can be an integer between 3
2145 and 13, default value is 5.
2148 Set the luma effect strength. It can be a float number between -2.0
2149 and 5.0, default value is 1.0.
2151 @item chroma_msize_x
2152 Set the chroma matrix horizontal size. It can be an integer between 3
2153 and 13, default value is 5.
2155 @item chroma_msize_y
2156 Set the chroma matrix vertical size. It can be an integer between 3
2157 and 13, default value is 5.
2160 Set the chroma effect strength. It can be a float number between -2.0
2161 and 5.0, default value is 0.0.
2166 # Strong luma sharpen effect parameters
2169 # Strong blur of both luma and chroma parameters
2170 unsharp=7:7:-2:7:7:-2
2172 # Use the default values with @command{avconv}
2173 ./avconv -i in.avi -vf "unsharp" out.mp4
2178 Flip the input video vertically.
2181 ./avconv -i in.avi -vf "vflip" out.avi
2186 Deinterlace the input video ("yadif" means "yet another deinterlacing
2189 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
2191 @var{mode} specifies the interlacing mode to adopt, accepts one of the
2196 output 1 frame for each frame
2198 output 1 frame for each field
2200 like 0 but skips spatial interlacing check
2202 like 1 but skips spatial interlacing check
2207 @var{parity} specifies the picture field parity assumed for the input
2208 interlaced video, accepts one of the following values:
2212 assume top field first
2214 assume bottom field first
2216 enable automatic detection
2219 Default value is -1.
2220 If interlacing is unknown or decoder does not export this information,
2221 top field first will be assumed.
2223 @var{auto} specifies if deinterlacer should trust the interlaced flag
2224 and only deinterlace frames marked as interlaced
2228 deinterlace all frames
2230 only deinterlace frames marked as interlaced
2235 @c man end VIDEO FILTERS
2237 @chapter Video Sources
2238 @c man begin VIDEO SOURCES
2240 Below is a description of the currently available video sources.
2244 Buffer video frames, and make them available to the filter chain.
2246 This source is mainly intended for a programmatic use, in particular
2247 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
2249 This filter accepts the following parameters:
2260 Name of the input video pixel format.
2263 The time base used for input timestamps.
2266 Sample (pixel) aspect ratio of the input video.
2272 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
2275 will instruct the source to accept video frames with size 320x240 and
2276 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2277 square pixels (1:1 sample aspect ratio).
2281 Provide an uniformly colored input.
2283 It accepts the following parameters:
2284 @var{color}:@var{frame_size}:@var{frame_rate}
2286 Follows the description of the accepted parameters.
2291 Specify the color of the source. It can be the name of a color (case
2292 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2293 alpha specifier. The default value is "black".
2296 Specify the size of the sourced video, it may be a string of the form
2297 @var{width}x@var{height}, or the name of a size abbreviation. The
2298 default value is "320x240".
2301 Specify the frame rate of the sourced video, as the number of frames
2302 generated per second. It has to be a string in the format
2303 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2304 number or a valid video frame rate abbreviation. The default value is
2309 For example the following graph description will generate a red source
2310 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2311 frames per second, which will be overlayed over the source connected
2312 to the pad with identifier "in".
2315 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2320 Read a video stream from a movie container.
2322 Note that this source is a hack that bypasses the standard input path. It can be
2323 useful in applications that do not support arbitrary filter graphs, but its use
2324 is discouraged in those that do. Specifically in @command{avconv} this filter
2325 should never be used, the @option{-filter_complex} option fully replaces it.
2327 It accepts the syntax: @var{movie_name}[:@var{options}] where
2328 @var{movie_name} is the name of the resource to read (not necessarily
2329 a file but also a device or a stream accessed through some protocol),
2330 and @var{options} is an optional sequence of @var{key}=@var{value}
2331 pairs, separated by ":".
2333 The description of the accepted options follows.
2337 @item format_name, f
2338 Specifies the format assumed for the movie to read, and can be either
2339 the name of a container or an input device. If not specified the
2340 format is guessed from @var{movie_name} or by probing.
2342 @item seek_point, sp
2343 Specifies the seek point in seconds, the frames will be output
2344 starting from this seek point, the parameter is evaluated with
2345 @code{av_strtod} so the numerical value may be suffixed by an IS
2346 postfix. Default value is "0".
2348 @item stream_index, si
2349 Specifies the index of the video stream to read. If the value is -1,
2350 the best suited video stream will be automatically selected. Default
2355 This filter allows to overlay a second video on top of main input of
2356 a filtergraph as shown in this graph:
2358 input -----------> deltapts0 --> overlay --> output
2361 movie --> scale--> deltapts1 -------+
2364 Some examples follow:
2366 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2367 # on top of the input labelled as "in".
2368 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2369 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2371 # read from a video4linux2 device, and overlay it on top of the input
2373 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2374 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2380 Null video source, never return images. It is mainly useful as a
2381 template and to be employed in analysis / debugging tools.
2383 It accepts as optional parameter a string of the form
2384 @var{width}:@var{height}:@var{timebase}.
2386 @var{width} and @var{height} specify the size of the configured
2387 source. The default values of @var{width} and @var{height} are
2388 respectively 352 and 288 (corresponding to the CIF size format).
2390 @var{timebase} specifies an arithmetic expression representing a
2391 timebase. The expression can contain the constants "PI", "E", "PHI",
2392 "AVTB" (the default timebase), and defaults to the value "AVTB".
2396 Provide a frei0r source.
2398 To enable compilation of this filter you need to install the frei0r
2399 header and configure Libav with --enable-frei0r.
2401 This source accepts the following options:
2406 The size of the video to generate, may be a string of the form
2407 @var{width}x@var{height} or a frame size abbreviation.
2410 Framerate of the generated video, may be a string of the form
2411 @var{num}/@var{den} or a frame rate abbreviation.
2414 The name to the frei0r source to load. For more information regarding frei0r and
2415 how to set the parameters read the section @ref{frei0r} in the description of
2419 A '|'-separated list of parameters to pass to the frei0r source.
2423 Some examples follow:
2425 # generate a frei0r partik0l source with size 200x200 and framerate 10
2426 # which is overlayed on the overlay filter main input
2427 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
2430 @section rgbtestsrc, testsrc
2432 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2433 detecting RGB vs BGR issues. You should see a red, green and blue
2434 stripe from top to bottom.
2436 The @code{testsrc} source generates a test video pattern, showing a
2437 color pattern, a scrolling gradient and a timestamp. This is mainly
2438 intended for testing purposes.
2440 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2441 separated by ":". The description of the accepted options follows.
2446 Specify the size of the sourced video, it may be a string of the form
2447 @var{width}x@var{height}, or the name of a size abbreviation. The
2448 default value is "320x240".
2451 Specify the frame rate of the sourced video, as the number of frames
2452 generated per second. It has to be a string in the format
2453 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2454 number or a valid video frame rate abbreviation. The default value is
2458 Set the sample aspect ratio of the sourced video.
2461 Set the video duration of the sourced video. The accepted syntax is:
2463 [-]HH[:MM[:SS[.m...]]]
2466 See also the function @code{av_parse_time()}.
2468 If not specified, or the expressed duration is negative, the video is
2469 supposed to be generated forever.
2472 For example the following:
2474 testsrc=duration=5.3:size=qcif:rate=10
2477 will generate a video with a duration of 5.3 seconds, with size
2478 176x144 and a framerate of 10 frames per second.
2480 @c man end VIDEO SOURCES
2482 @chapter Video Sinks
2483 @c man begin VIDEO SINKS
2485 Below is a description of the currently available video sinks.
2489 Buffer video frames, and make them available to the end of the filter
2492 This sink is intended for a programmatic use through the interface defined in
2493 @file{libavfilter/buffersink.h}.
2497 Null video sink, do absolutely nothing with the input video. It is
2498 mainly useful as a template and to be employed in analysis / debugging
2501 @c man end VIDEO SINKS