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 @section Filtergraph syntax
19 A filtergraph can be represented using a textual representation, which
20 is recognized by the @code{-vf} and @code{-af} options of the ff*
21 tools, and by the @code{av_parse_graph()} function defined in
22 @file{libavfilter/avfiltergraph}.
24 A filterchain consists of a sequence of connected filters, each one
25 connected to the previous one in the sequence. A filterchain is
26 represented by a list of ","-separated filter descriptions.
28 A filtergraph consists of a sequence of filterchains. A sequence of
29 filterchains is represented by a list of ";"-separated filterchain
32 A filter is represented by a string of the form:
33 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
35 @var{filter_name} is the name of the filter class of which the
36 described filter is an instance of, and has to be the name of one of
37 the filter classes registered in the program.
38 The name of the filter class is optionally followed by a string
41 @var{arguments} is a string which contains the parameters used to
42 initialize the filter instance, and are described in the filter
45 The list of arguments can be quoted using the character "'" as initial
46 and ending mark, and the character '\' for escaping the characters
47 within the quoted text; otherwise the argument string is considered
48 terminated when the next special character (belonging to the set
49 "[]=;,") is encountered.
51 The name and arguments of the filter are optionally preceded and
52 followed by a list of link labels.
53 A link label allows to name a link and associate it to a filter output
54 or input pad. The preceding labels @var{in_link_1}
55 ... @var{in_link_N}, are associated to the filter input pads,
56 the following labels @var{out_link_1} ... @var{out_link_M}, are
57 associated to the output pads.
59 When two link labels with the same name are found in the
60 filtergraph, a link between the corresponding input and output pad is
63 If an output pad is not labelled, it is linked by default to the first
64 unlabelled input pad of the next filter in the filterchain.
65 For example in the filterchain:
67 nullsrc, split[L1], [L2]overlay, nullsink
69 the split filter instance has two output pads, and the overlay filter
70 instance two input pads. The first output pad of split is labelled
71 "L1", the first input pad of overlay is labelled "L2", and the second
72 output pad of split is linked to the second input pad of overlay,
73 which are both unlabelled.
75 In a complete filterchain all the unlabelled filter input and output
76 pads must be connected. A filtergraph is considered valid if all the
77 filter input and output pads of all the filterchains are connected.
79 Follows a BNF description for the filtergraph syntax:
81 @var{NAME} ::= sequence of alphanumeric characters and '_'
82 @var{LINKLABEL} ::= "[" @var{NAME} "]"
83 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
84 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
85 @var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
86 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
87 @var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
90 @c man end FILTERGRAPH DESCRIPTION
92 @chapter Audio Filters
93 @c man begin AUDIO FILTERS
95 When you configure your FFmpeg build, you can disable any of the
96 existing filters using --disable-filters.
97 The configure output will show the audio filters included in your
100 Below is a description of the currently available audio filters.
104 Pass the audio source unchanged to the output.
106 @c man end AUDIO FILTERS
108 @chapter Audio Sources
109 @c man begin AUDIO SOURCES
111 Below is a description of the currently available audio sources.
115 Null audio source, never return audio frames. It is mainly useful as a
116 template and to be employed in analysis / debugging tools.
118 It accepts as optional parameter a string of the form
119 @var{sample_rate}:@var{channel_layout}.
121 @var{sample_rate} specify the sample rate, and defaults to 44100.
123 @var{channel_layout} specify the channel layout, and can be either an
124 integer or a string representing a channel layout. The default value
125 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
127 Check the channel_layout_map definition in
128 @file{libavcodec/audioconvert.c} for the mapping between strings and
129 channel layout values.
131 Follow some examples:
133 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
140 @c man end AUDIO SOURCES
143 @c man begin AUDIO SINKS
145 Below is a description of the currently available audio sinks.
149 Null audio sink, do absolutely nothing with the input audio. It is
150 mainly useful as a template and to be employed in analysis / debugging
153 @c man end AUDIO SINKS
155 @chapter Video Filters
156 @c man begin VIDEO FILTERS
158 When you configure your FFmpeg build, you can disable any of the
159 existing filters using --disable-filters.
160 The configure output will show the video filters included in your
163 Below is a description of the currently available video filters.
167 Detect frames that are (almost) completely black. Can be useful to
168 detect chapter transitions or commercials. Output lines consist of
169 the frame number of the detected frame, the percentage of blackness,
170 the position in the file if known or -1 and the timestamp in seconds.
172 In order to display the output lines, you need to set the loglevel at
173 least to the AV_LOG_INFO value.
175 The filter accepts the syntax:
177 blackframe[=@var{amount}:[@var{threshold}]]
180 @var{amount} is the percentage of the pixels that have to be below the
181 threshold, and defaults to 98.
183 @var{threshold} is the threshold below which a pixel value is
184 considered black, and defaults to 32.
188 Apply boxblur algorithm to the input video.
190 This filter accepts the parameters:
191 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
193 Chroma and alpha parameters are optional, if not specified they default
194 to the corresponding values set for @var{luma_radius} and
197 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
198 the radius in pixels of the box used for blurring the corresponding
199 input plane. They are expressions, and can contain the following
203 the input width and heigth in pixels
206 the input chroma image width and height in pixels
209 horizontal and vertical chroma subsample values. For example for the
210 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
213 The radius must be a non-negative number, and must be not greater than
214 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
215 and of @code{min(cw,ch)/2} for the chroma planes.
217 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
218 how many times the boxblur filter is applied to the corresponding
221 Some examples follow:
226 Apply a boxblur filter with luma, chroma, and alpha radius
233 Set luma radius to 2, alpha and chroma radius to 0
239 Set luma and chroma radius to a fraction of the video dimension
241 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
248 Copy the input source unchanged to the output. Mainly useful for
253 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
255 The parameters are expressions containing the following constants:
259 the corresponding mathematical approximated values for e
260 (euler number), pi (greek PI), PHI (golden ratio)
263 the computed values for @var{x} and @var{y}. They are evaluated for
267 the input width and heigth
270 same as @var{in_w} and @var{in_h}
273 the output (cropped) width and heigth
276 same as @var{out_w} and @var{out_h}
279 the number of input frame, starting from 0
282 the position in the file of the input frame, NAN if unknown
285 timestamp expressed in seconds, NAN if the input timestamp is unknown
289 The @var{out_w} and @var{out_h} parameters specify the expressions for
290 the width and height of the output (cropped) video. They are
291 evaluated just at the configuration of the filter.
293 The default value of @var{out_w} is "in_w", and the default value of
294 @var{out_h} is "in_h".
296 The expression for @var{out_w} may depend on the value of @var{out_h},
297 and the expression for @var{out_h} may depend on @var{out_w}, but they
298 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
299 evaluated after @var{out_w} and @var{out_h}.
301 The @var{x} and @var{y} parameters specify the expressions for the
302 position of the top-left corner of the output (non-cropped) area. They
303 are evaluated for each frame. If the evaluated value is not valid, it
304 is approximated to the nearest valid value.
306 The default value of @var{x} is "(in_w-out_w)/2", and the default
307 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
308 the center of the input image.
310 The expression for @var{x} may depend on @var{y}, and the expression
311 for @var{y} may depend on @var{x}.
313 Follow some examples:
315 # crop the central input area with size 100x100
318 # crop the central input area with size 2/3 of the input video
319 "crop=2/3*in_w:2/3*in_h"
321 # crop the input video central square
324 # delimit the rectangle with the top-left corner placed at position
325 # 100:100 and the right-bottom corner corresponding to the right-bottom
326 # corner of the input image.
327 crop=in_w-100:in_h-100:100:100
329 # crop 10 pixels from the left and right borders, and 20 pixels from
330 # the top and bottom borders
331 "crop=in_w-2*10:in_h-2*20"
333 # keep only the bottom right quarter of the input image
334 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
336 # crop height for getting Greek harmony
337 "crop=in_w:1/PHI*in_w"
340 "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)"
342 # erratic camera effect depending on timestamp
343 "crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
345 # set x depending on the value of y
346 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
351 Auto-detect crop size.
353 Calculate necessary cropping parameters and prints the recommended
354 parameters through the logging system. The detected dimensions
355 correspond to the non-black area of the input video.
357 It accepts the syntax:
359 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
365 Threshold, which can be optionally specified from nothing (0) to
366 everything (255), defaults to 24.
369 Value which the width/height should be divisible by, defaults to
370 16. The offset is automatically adjusted to center the video. Use 2 to
371 get only even dimensions (needed for 4:2:2 video). 16 is best when
372 encoding to most video codecs.
375 Counter that determines after how many frames cropdetect will reset
376 the previously detected largest video area and start over to detect
377 the current optimal crop area. Defaults to 0.
379 This can be useful when channel logos distort the video area. 0
380 indicates never reset and return the largest area encountered during
386 Draw a colored box on the input image.
388 It accepts the syntax:
390 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
396 Specify the top left corner coordinates of the box. Default to 0.
399 Specify the width and height of the box, if 0 they are interpreted as
400 the input width and height. Default to 0.
403 Specify the color of the box to write, it can be the name of a color
404 (case insensitive match) or a 0xRRGGBB[AA] sequence.
407 Follow some examples:
409 # draw a black box around the edge of the input image
412 # draw a box with color red and an opacity of 50%
413 drawbox=10:20:200:60:red@@0.5"
418 Draw text string or text from specified file on top of video using the
421 To enable compilation of this filter you need to configure FFmpeg with
422 @code{--enable-libfreetype}.
424 The filter also recognizes strftime() sequences in the provided text
425 and expands them accordingly. Check the documentation of strftime().
427 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
430 The description of the accepted parameters follows.
435 The font file to be used for drawing text. Path must be included.
436 This parameter is mandatory.
439 The text string to be drawn. The text must be a sequence of UTF-8
441 This parameter is mandatory if no file is specified with the parameter
445 A text file containing text to be drawn. The text must be a sequence
446 of UTF-8 encoded characters.
448 This parameter is mandatory if no text string is specified with the
449 parameter @var{text}.
451 If both text and textfile are specified, an error is thrown.
454 The offsets where text will be drawn within the video frame.
455 Relative to the top/left border of the output image.
457 The default value of @var{x} and @var{y} is 0.
460 The font size to be used for drawing text.
461 The default value of @var{fontsize} is 16.
464 The color to be used for drawing fonts.
465 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
466 (e.g. "0xff000033"), possibly followed by an alpha specifier.
467 The default value of @var{fontcolor} is "black".
470 The color to be used for drawing box around text.
471 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
472 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
473 The default value of @var{boxcolor} is "white".
476 Used to draw a box around text using background color.
477 Value should be either 1 (enable) or 0 (disable).
478 The default value of @var{box} is 0.
480 @item shadowx, shadowy
481 The x and y offsets for the text shadow position with respect to the
482 position of the text. They can be either positive or negative
483 values. Default value for both is "0".
486 The color to be used for drawing a shadow behind the drawn text. It
487 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
488 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
489 The default value of @var{shadowcolor} is "black".
492 Flags to be used for loading the fonts.
494 The flags map the corresponding flags supported by libfreetype, and are
495 a combination of the following values:
502 @item vertical_layout
506 @item ignore_global_advance_width
508 @item ignore_transform
515 Default value is "render".
517 For more information consult the documentation for the FT_LOAD_*
521 The size in number of spaces to use for rendering the tab.
525 For example the command:
527 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
530 will draw "Test Text" with font FreeSerif, using the default values
531 for the optional parameters.
535 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
536 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
539 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
540 and y=50 (counting from the top-left corner of the screen), text is
541 yellow with a red box around it. Both the text and the box have an
544 Note that the double quotes are not necessary if spaces are not used
545 within the parameter list.
547 For more information about libfreetype, check:
548 @url{http://www.freetype.org/}.
552 Apply fade-in/out effect to input video.
554 It accepts the parameters:
555 @var{type}:@var{start_frame}:@var{nb_frames}
557 @var{type} specifies if the effect type, can be either "in" for
558 fade-in, or "out" for a fade-out effect.
560 @var{start_frame} specifies the number of the start frame for starting
561 to apply the fade effect.
563 @var{nb_frames} specifies the number of frames for which the fade
564 effect has to last. At the end of the fade-in effect the output video
565 will have the same intensity as the input video, at the end of the
566 fade-out transition the output video will be completely black.
568 A few usage examples follow, usable too as test scenarios.
570 # fade in first 30 frames of video
573 # fade out last 45 frames of a 200-frame video
576 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
577 fade=in:0:25, fade=out:975:25
579 # make first 5 frames black, then fade in from frame 5-24
585 Transform the field order of the input video.
587 It accepts one parameter which specifies the required field order that
588 the input interlaced video will be transformed to. The parameter can
589 assume one of the following values:
593 output bottom field first
595 output top field first
598 Default value is "tff".
600 Transformation is achieved by shifting the picture content up or down
601 by one line, and filling the remaining line with appropriate picture content.
602 This method is consistent with most broadcast field order converters.
604 If the input video is not flagged as being interlaced, or it is already
605 flagged as being of the required output field order then this filter does
606 not alter the incoming video.
608 This filter is very useful when converting to or from PAL DV material,
609 which is bottom field first.
613 ./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
618 Buffer input images and send them when they are requested.
620 This filter is mainly useful when auto-inserted by the libavfilter
623 The filter does not take parameters.
627 Convert the input video to one of the specified pixel formats.
628 Libavfilter will try to pick one that is supported for the input to
631 The filter accepts a list of pixel format names, separated by ":",
632 for example "yuv420p:monow:rgb24".
634 Some examples follow:
636 # convert the input video to the format "yuv420p"
639 # convert the input video to any of the formats in the list
640 format=yuv420p:yuv444p:yuv410p
646 Apply a frei0r effect to the input video.
648 To enable compilation of this filter you need to install the frei0r
649 header and configure FFmpeg with --enable-frei0r.
651 The filter supports the syntax:
653 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
656 @var{filter_name} is the name to the frei0r effect to load. If the
657 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
658 is searched in each one of the directories specified by the colon
659 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
660 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
661 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
663 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
664 for the frei0r effect.
666 A frei0r effect parameter can be a boolean (whose values are specified
667 with "y" and "n"), a double, a color (specified by the syntax
668 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
669 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
670 description), a position (specified by the syntax @var{X}/@var{Y},
671 @var{X} and @var{Y} being float numbers) and a string.
673 The number and kind of parameters depend on the loaded effect. If an
674 effect parameter is not specified the default value is set.
676 Some examples follow:
678 # apply the distort0r effect, set the first two double parameters
679 frei0r=distort0r:0.5:0.01
681 # apply the colordistance effect, takes a color as first parameter
682 frei0r=colordistance:0.2/0.3/0.4
683 frei0r=colordistance:violet
684 frei0r=colordistance:0x112233
686 # apply the perspective effect, specify the top left and top right
688 frei0r=perspective:0.2/0.2:0.8/0.2
691 For more information see:
692 @url{http://piksel.org/frei0r}
696 Fix the banding artifacts that are sometimes introduced into nearly flat
697 regions by truncation to 8bit colordepth.
698 Interpolate the gradients that should go where the bands are, and
701 This filter is designed for playback only. Do not use it prior to
702 lossy compression, because compression tends to lose the dither and
703 bring back the bands.
705 The filter takes two optional parameters, separated by ':':
706 @var{strength}:@var{radius}
708 @var{strength} is the maximum amount by which the filter will change
709 any one pixel. Also the threshold for detecting nearly flat
710 regions. Acceptable values range from .51 to 255, default value is
711 1.2, out-of-range values will be clipped to the valid range.
713 @var{radius} is the neighborhood to fit the gradient to. A larger
714 radius makes for smoother gradients, but also prevents the filter from
715 modifying the pixels near detailed regions. Acceptable values are
716 8-32, default value is 16, out-of-range values will be clipped to the
729 Flip the input video horizontally.
731 For example to horizontally flip the video in input with
734 ffmpeg -i in.avi -vf "hflip" out.avi
739 High precision/quality 3d denoise filter. This filter aims to reduce
740 image noise producing smooth images and making still images really
741 still. It should enhance compressibility.
743 It accepts the following optional parameters:
744 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
748 a non-negative float number which specifies spatial luma strength,
752 a non-negative float number which specifies spatial chroma strength,
753 defaults to 3.0*@var{luma_spatial}/4.0
756 a float number which specifies luma temporal strength, defaults to
757 6.0*@var{luma_spatial}/4.0
760 a float number which specifies chroma temporal strength, defaults to
761 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
764 @section lut, lutrgb, lutyuv
766 Compute a look-up table for binding each pixel component input value
767 to an output value, and apply it to input video.
769 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
770 to an RGB input video.
772 These filters accept in input a ":"-separated list of options, which
773 specify the expressions used for computing the lookup table for the
774 corresponding pixel component values.
776 The @var{lut} filter requires either YUV or RGB pixel formats in
777 input, and accepts the options:
779 @var{c0} (first pixel component)
780 @var{c1} (second pixel component)
781 @var{c2} (third pixel component)
782 @var{c3} (fourth pixel component, corresponds to the alpha component)
785 The exact component associated to each option depends on the format in
788 The @var{lutrgb} filter requires RGB pixel formats in input, and
791 @var{r} (red component)
792 @var{g} (green component)
793 @var{b} (blue component)
794 @var{a} (alpha component)
797 The @var{lutyuv} filter requires YUV pixel formats in input, and
800 @var{y} (Y/luminance component)
801 @var{u} (U/Cb component)
802 @var{v} (V/Cr component)
803 @var{a} (alpha component)
806 The expressions can contain the following constants and functions:
810 the corresponding mathematical approximated values for e
811 (euler number), pi (greek PI), PHI (golden ratio)
814 the input width and heigth
817 input value for the pixel component
820 the input value clipped in the @var{minval}-@var{maxval} range
823 maximum value for the pixel component
826 minimum value for the pixel component
829 the negated value for the pixel component value clipped in the
830 @var{minval}-@var{maxval} range , it corresponds to the expression
831 "maxval-clipval+minval"
834 the computed value in @var{val} clipped in the
835 @var{minval}-@var{maxval} range
837 @item gammaval(gamma)
838 the computed gamma correction value of the pixel component value
839 clipped in the @var{minval}-@var{maxval} range, corresponds to the
841 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
845 All expressions default to "val".
847 Some examples follow:
850 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
851 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
853 # the above is the same as
854 lutrgb="r=negval:g=negval:b=negval"
855 lutyuv="y=negval:u=negval:v=negval"
860 # remove chroma components, turns the video into a graytone image
863 # apply a luma burning effect
866 # remove green and blue components
869 # set a constant alpha channel value on input
870 format=rgba,lutrgb=a="maxval-minval/2"
872 # correct luminance gamma by a 0.5 factor
873 lutyuv=y=gammaval(0.5)
878 Apply an MPlayer filter to the input video.
880 This filter provides a wrapper around most of the filters of
883 This wrapper is considered experimental. Some of the wrapped filters
884 may not work properly and we may drop support for them, as they will
885 be implemented natively into FFmpeg. Thus you should avoid
886 depending on them when writing portable scripts.
888 The filters accepts the parameters:
889 @var{filter_name}[:=]@var{filter_params}
891 @var{filter_name} is the name of a supported MPlayer filter,
892 @var{filter_params} is a string containing the parameters accepted by
895 The list of the currently supported filters follows:
954 The parameter syntax and behavior for the listed filters are the same
955 of the corresponding MPlayer filters. For detailed instructions check
956 the "VIDEO FILTERS" section in the MPlayer manual.
958 Some examples follow:
960 # remove a logo by interpolating the surrounding pixels
961 mp=delogo=200:200:80:20:1
963 # adjust gamma, brightness, contrast
966 # tweak hue and saturation
970 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
976 This filter accepts an integer in input, if non-zero it negates the
977 alpha component (if available). The default value in input is 0.
981 Force libavfilter not to use any of the specified pixel formats for the
982 input to the next filter.
984 The filter accepts a list of pixel format names, separated by ":",
985 for example "yuv420p:monow:rgb24".
987 Some examples follow:
989 # force libavfilter to use a format different from "yuv420p" for the
990 # input to the vflip filter
991 noformat=yuv420p,vflip
993 # convert the input video to any of the formats not contained in the list
994 noformat=yuv420p:yuv444p:yuv410p
999 Pass the video source unchanged to the output.
1003 Apply video transform using libopencv.
1005 To enable this filter install libopencv library and headers and
1006 configure FFmpeg with --enable-libopencv.
1008 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1010 @var{filter_name} is the name of the libopencv filter to apply.
1012 @var{filter_params} specifies the parameters to pass to the libopencv
1013 filter. If not specified the default values are assumed.
1015 Refer to the official libopencv documentation for more precise
1017 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1019 Follows the list of supported libopencv filters.
1024 Dilate an image by using a specific structuring element.
1025 This filter corresponds to the libopencv function @code{cvDilate}.
1027 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1029 @var{struct_el} represents a structuring element, and has the syntax:
1030 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1032 @var{cols} and @var{rows} represent the number of colums and rows of
1033 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1034 point, and @var{shape} the shape for the structuring element, and
1035 can be one of the values "rect", "cross", "ellipse", "custom".
1037 If the value for @var{shape} is "custom", it must be followed by a
1038 string of the form "=@var{filename}". The file with name
1039 @var{filename} is assumed to represent a binary image, with each
1040 printable character corresponding to a bright pixel. When a custom
1041 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1042 or columns and rows of the read file are assumed instead.
1044 The default value for @var{struct_el} is "3x3+0x0/rect".
1046 @var{nb_iterations} specifies the number of times the transform is
1047 applied to the image, and defaults to 1.
1049 Follow some example:
1051 # use the default values
1054 # dilate using a structuring element with a 5x5 cross, iterate two times
1055 ocv=dilate=5x5+2x2/cross:2
1057 # read the shape from the file diamond.shape, iterate two times
1058 # the file diamond.shape may contain a pattern of characters like this:
1064 # the specified cols and rows are ignored (but not the anchor point coordinates)
1065 ocv=0x0+2x2/custom=diamond.shape:2
1070 Erode an image by using a specific structuring element.
1071 This filter corresponds to the libopencv function @code{cvErode}.
1073 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1074 with the same syntax and semantics as the @ref{dilate} filter.
1078 Smooth the input video.
1080 The filter takes the following parameters:
1081 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1083 @var{type} is the type of smooth filter to apply, and can be one of
1084 the following values: "blur", "blur_no_scale", "median", "gaussian",
1085 "bilateral". The default value is "gaussian".
1087 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1088 parameters whose meanings depend on smooth type. @var{param1} and
1089 @var{param2} accept integer positive values or 0, @var{param3} and
1090 @var{param4} accept float values.
1092 The default value for @var{param1} is 3, the default value for the
1093 other parameters is 0.
1095 These parameters correspond to the parameters assigned to the
1096 libopencv function @code{cvSmooth}.
1100 Overlay one video on top of another.
1102 It takes two inputs and one output, the first input is the "main"
1103 video on which the second input is overlayed.
1105 It accepts the parameters: @var{x}:@var{y}.
1107 @var{x} is the x coordinate of the overlayed video on the main video,
1108 @var{y} is the y coordinate. The parameters are expressions containing
1109 the following parameters:
1112 @item main_w, main_h
1113 main input width and height
1116 same as @var{main_w} and @var{main_h}
1118 @item overlay_w, overlay_h
1119 overlay input width and height
1122 same as @var{overlay_w} and @var{overlay_h}
1125 Be aware that frames are taken from each input video in timestamp
1126 order, hence, if their initial timestamps differ, it is a a good idea
1127 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1128 have them begin in the same zero timestamp, as it does the example for
1129 the @var{movie} filter.
1131 Follow some examples:
1133 # draw the overlay at 10 pixels from the bottom right
1134 # corner of the main video.
1135 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1137 # insert a transparent PNG logo in the bottom left corner of the input
1138 movie=logo.png [logo];
1139 [in][logo] overlay=10:main_h-overlay_h-10 [out]
1141 # insert 2 different transparent PNG logos (second logo on bottom
1143 movie=logo1.png [logo1];
1144 movie=logo2.png [logo2];
1145 [in][logo1] overlay=10:H-h-10 [in+logo1];
1146 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
1148 # add a transparent color layer on top of the main video,
1149 # WxH specifies the size of the main input to the overlay filter
1150 color=red@.3:WxH [over]; [in][over] overlay [out]
1153 You can chain togheter more overlays but the efficiency of such
1154 approach is yet to be tested.
1158 Add paddings to the input image, and places the original input at the
1159 given coordinates @var{x}, @var{y}.
1161 It accepts the following parameters:
1162 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1164 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1165 expressions containing the following constants:
1169 the corresponding mathematical approximated values for e
1170 (euler number), pi (greek PI), phi (golden ratio)
1173 the input video width and heigth
1176 same as @var{in_w} and @var{in_h}
1179 the output width and heigth, that is the size of the padded area as
1180 specified by the @var{width} and @var{height} expressions
1183 same as @var{out_w} and @var{out_h}
1186 x and y offsets as specified by the @var{x} and @var{y}
1187 expressions, or NAN if not yet specified
1190 input display aspect ratio, same as @var{iw} / @var{ih}
1193 input sample aspect ratio
1196 horizontal and vertical chroma subsample values. For example for the
1197 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1200 Follows the description of the accepted parameters.
1205 Specify the size of the output image with the paddings added. If the
1206 value for @var{width} or @var{height} is 0, the corresponding input size
1207 is used for the output.
1209 The @var{width} expression can reference the value set by the
1210 @var{height} expression, and viceversa.
1212 The default value of @var{width} and @var{height} is 0.
1216 Specify the offsets where to place the input image in the padded area
1217 with respect to the top/left border of the output image.
1219 The @var{x} expression can reference the value set by the @var{y}
1220 expression, and viceversa.
1222 The default value of @var{x} and @var{y} is 0.
1226 Specify the color of the padded area, it can be the name of a color
1227 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1229 The default value of @var{color} is "black".
1233 Some examples follow:
1236 # Add paddings with color "violet" to the input video. Output video
1237 # size is 640x480, the top-left corner of the input video is placed at
1239 pad=640:480:0:40:violet
1241 # pad the input to get an output with dimensions increased bt 3/2,
1242 # and put the input video at the center of the padded area
1243 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1245 # pad the input to get a squared output with size equal to the maximum
1246 # value between the input width and height, and put the input video at
1247 # the center of the padded area
1248 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1250 # pad the input to get a final w/h ratio of 16:9
1251 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1253 # double output size and put the input video in the bottom-right
1254 # corner of the output padded area
1255 pad="2*iw:2*ih:ow-iw:oh-ih"
1258 @section pixdesctest
1260 Pixel format descriptor test filter, mainly useful for internal
1261 testing. The output video should be equal to the input video.
1265 format=monow, pixdesctest
1268 can be used to test the monowhite pixel format descriptor definition.
1272 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1274 The parameters @var{width} and @var{height} are expressions containing
1275 the following constants:
1279 the corresponding mathematical approximated values for e
1280 (euler number), pi (greek PI), phi (golden ratio)
1283 the input width and heigth
1286 same as @var{in_w} and @var{in_h}
1289 the output (cropped) width and heigth
1292 same as @var{out_w} and @var{out_h}
1295 input display aspect ratio, same as @var{iw} / @var{ih}
1298 input sample aspect ratio
1301 horizontal and vertical chroma subsample values. For example for the
1302 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1305 If the input image format is different from the format requested by
1306 the next filter, the scale filter will convert the input to the
1309 If the value for @var{width} or @var{height} is 0, the respective input
1310 size is used for the output.
1312 If the value for @var{width} or @var{height} is -1, the scale filter will
1313 use, for the respective output size, a value that maintains the aspect
1314 ratio of the input image.
1316 The default value of @var{width} and @var{height} is 0.
1318 Some examples follow:
1320 # scale the input video to a size of 200x100.
1323 # scale the input to 2x
1325 # the above is the same as
1328 # scale the input to half size
1331 # increase the width, and set the height to the same size
1334 # seek for Greek harmony
1338 # increase the height, and set the width to 3/2 of the height
1341 # increase the size, but make the size a multiple of the chroma
1342 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1344 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1345 scale='min(500\, iw*3/2):-1'
1349 Select frames to pass in output.
1351 It accepts in input an expression, which is evaluated for each input
1352 frame. If the expression is evaluated to a non-zero value, the frame
1353 is selected and passed to the output, otherwise it is discarded.
1355 The expression can contain the following constants:
1368 the sequential number of the filtered frame, starting from 0
1371 the sequential number of the selected frame, starting from 0
1373 @item prev_selected_n
1374 the sequential number of the last selected frame, NAN if undefined
1377 timebase of the input timestamps
1380 the PTS (Presentation TimeStamp) of the filtered video frame,
1381 expressed in @var{TB} units, NAN if undefined
1384 the PTS (Presentation TimeStamp) of the filtered video frame,
1385 expressed in seconds, NAN if undefined
1388 the PTS of the previously filtered video frame, NAN if undefined
1390 @item prev_selected_pts
1391 the PTS of the last previously filtered video frame, NAN if undefined
1393 @item prev_selected_t
1394 the PTS of the last previously selected video frame, NAN if undefined
1397 the PTS of the first video frame in the video, NAN if undefined
1400 the time of the first video frame in the video, NAN if undefined
1403 the picture type of the filtered frame, can assume one of the following
1415 @item interlace_type
1416 the frame interlace type, can assume one of the following values:
1418 @item INTERLACE_TYPE_P
1419 the frame is progressive (not interlaced)
1420 @item INTERLACE_TYPE_T
1421 the frame is top-field-first
1422 @item INTERLACE_TYPE_B
1423 the frame is bottom-field-first
1427 1 if the filtered frame is a key-frame, 0 otherwise
1430 the position in the file of the filtered frame, -1 if the information
1431 is not available (e.g. for synthetic video)
1434 The default value of the select expression is "1".
1436 Some examples follow:
1439 # select all frames in input
1442 # the above is the same as:
1448 # select only I-frames
1449 select='eq(pict_type\,PICT_TYPE_I)'
1451 # select one frame every 100
1452 select='not(mod(n\,100))'
1454 # select only frames contained in the 10-20 time interval
1455 select='gte(t\,10)*lte(t\,20)'
1457 # select only I frames contained in the 10-20 time interval
1458 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,PICT_TYPE_I)'
1460 # select frames with a minimum distance of 10 seconds
1461 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1467 Set the Display Aspect Ratio for the filter output video.
1469 This is done by changing the specified Sample (aka Pixel) Aspect
1470 Ratio, according to the following equation:
1471 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1473 Keep in mind that this filter does not modify the pixel dimensions of
1474 the video frame. Also the display aspect ratio set by this filter may
1475 be changed by later filters in the filterchain, e.g. in case of
1476 scaling or if another "setdar" or a "setsar" filter is applied.
1478 The filter accepts a parameter string which represents the wanted
1479 display aspect ratio.
1480 The parameter can be a floating point number string, or an expression
1481 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1482 numerator and denominator of the aspect ratio.
1483 If the parameter is not specified, it is assumed the value "0:1".
1485 For example to change the display aspect ratio to 16:9, specify:
1488 # the above is equivalent to
1492 See also the @ref{setsar} filter documentation.
1496 Change the PTS (presentation timestamp) of the input video frames.
1498 Accept in input an expression evaluated through the eval API, which
1499 can contain the following constants:
1503 the presentation timestamp in input
1515 the count of the input frame, starting from 0.
1518 the PTS of the first video frame
1521 tell if the current frame is interlaced
1524 original position in the file of the frame, or undefined if undefined
1525 for the current frame
1535 Some examples follow:
1538 # start counting PTS from zero
1550 # fixed rate 25 fps with some jitter
1551 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1557 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1559 Note that as a consequence of the application of this filter, the
1560 output display aspect ratio will change according to the following
1562 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1564 Keep in mind that the sample aspect ratio set by this filter may be
1565 changed by later filters in the filterchain, e.g. if another "setsar"
1566 or a "setdar" filter is applied.
1568 The filter accepts a parameter string which represents the wanted
1569 sample aspect ratio.
1570 The parameter can be a floating point number string, or an expression
1571 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1572 numerator and denominator of the aspect ratio.
1573 If the parameter is not specified, it is assumed the value "0:1".
1575 For example to change the sample aspect ratio to 10:11, specify:
1582 Set the timebase to use for the output frames timestamps.
1583 It is mainly useful for testing timebase configuration.
1585 It accepts in input an arithmetic expression representing a rational.
1586 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1587 default timebase), and "intb" (the input timebase).
1589 The default value for the input is "intb".
1591 Follow some examples.
1594 # set the timebase to 1/25
1597 # set the timebase to 1/10
1600 #set the timebase to 1001/1000
1603 #set the timebase to 2*intb
1606 #set the default timebase value
1612 Show a line containing various information for each input video frame.
1613 The input video is not modified.
1615 The shown line contains a sequence of key/value pairs of the form
1616 @var{key}:@var{value}.
1618 A description of each shown parameter follows:
1622 sequential number of the input frame, starting from 0
1625 Presentation TimeStamp of the input frame, expressed as a number of
1626 time base units. The time base unit depends on the filter input pad.
1629 Presentation TimeStamp of the input frame, expressed as a number of
1633 position of the frame in the input stream, -1 if this information in
1634 unavailable and/or meanigless (for example in case of synthetic video)
1640 sample aspect ratio of the input frame, expressed in the form
1644 size of the input frame, expressed in the form
1645 @var{width}x@var{height}
1648 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1649 for bottom field first)
1652 1 if the frame is a key frame, 0 otherwise
1655 picture type of the input frame ("I" for an I-frame, "P" for a
1656 P-frame, "B" for a B-frame, "?" for unknown type).
1657 Check also the documentation of the @code{AVPictureType} enum and of
1658 the @code{av_get_picture_type_char} function defined in
1659 @file{libavutil/avutil.h}.
1662 Adler-32 checksum of all the planes of the input frame
1664 @item plane_checksum
1665 Adler-32 checksum of each plane of the input frame, expressed in the form
1666 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
1671 Pass the images of input video on to next video filter as multiple
1675 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1678 The filter accepts the slice height as parameter. If the parameter is
1679 not specified it will use the default value of 16.
1681 Adding this in the beginning of filter chains should make filtering
1682 faster due to better use of the memory cache.
1686 Pass on the input video to two outputs. Both outputs are identical to
1691 [in] split [splitout1][splitout2];
1692 [splitout1] crop=100:100:0:0 [cropout];
1693 [splitout2] pad=200:200:100:100 [padout];
1696 will create two separate outputs from the same input, one cropped and
1701 Transpose rows with columns in the input video and optionally flip it.
1703 It accepts a parameter representing an integer, which can assume the
1708 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1716 Rotate by 90 degrees clockwise, that is:
1724 Rotate by 90 degrees counterclockwise, that is:
1732 Rotate by 90 degrees clockwise and vertically flip, that is:
1742 Sharpen or blur the input video.
1744 It accepts the following parameters:
1745 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1747 Negative values for the amount will blur the input video, while positive
1748 values will sharpen. All parameters are optional and default to the
1749 equivalent of the string '5:5:1.0:0:0:0.0'.
1754 Set the luma matrix horizontal size. It can be an integer between 3
1755 and 13, default value is 5.
1758 Set the luma matrix vertical size. It can be an integer between 3
1759 and 13, default value is 5.
1762 Set the luma effect strength. It can be a float number between -2.0
1763 and 5.0, default value is 1.0.
1765 @item chroma_msize_x
1766 Set the chroma matrix horizontal size. It can be an integer between 3
1767 and 13, default value is 0.
1769 @item chroma_msize_y
1770 Set the chroma matrix vertical size. It can be an integer between 3
1771 and 13, default value is 0.
1774 Set the chroma effect strength. It can be a float number between -2.0
1775 and 5.0, default value is 0.0.
1780 # Strong luma sharpen effect parameters
1783 # Strong blur of both luma and chroma parameters
1784 unsharp=7:7:-2:7:7:-2
1786 # Use the default values with @command{ffmpeg}
1787 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1792 Flip the input video vertically.
1795 ./ffmpeg -i in.avi -vf "vflip" out.avi
1800 Deinterlace the input video ("yadif" means "yet another deinterlacing
1803 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
1805 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1810 output 1 frame for each frame
1812 output 1 frame for each field
1814 like 0 but skips spatial interlacing check
1816 like 1 but skips spatial interlacing check
1821 @var{parity} specifies the picture field parity assumed for the input
1822 interlaced video, accepts one of the following values:
1826 assume bottom field first
1828 assume top field first
1830 enable automatic detection
1833 Default value is -1.
1834 If interlacing is unknown or decoder does not export this information,
1835 top field first will be assumed.
1837 @var{auto} specifies if deinterlacer should trust the interlaced flag
1838 and only deinterlace frames marked as interlaced
1842 deinterlace all frames
1844 only deinterlace frames marked as interlaced
1849 @c man end VIDEO FILTERS
1851 @chapter Video Sources
1852 @c man begin VIDEO SOURCES
1854 Below is a description of the currently available video sources.
1858 Buffer video frames, and make them available to the filter chain.
1860 This source is mainly intended for a programmatic use, in particular
1861 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1863 It accepts the following parameters:
1864 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}:@var{scale_params}
1866 All the parameters but @var{scale_params} need to be explicitely
1869 Follows the list of the accepted parameters.
1874 Specify the width and height of the buffered video frames.
1876 @item pix_fmt_string
1877 A string representing the pixel format of the buffered video frames.
1878 It may be a number corresponding to a pixel format, or a pixel format
1881 @item timebase_num, timebase_den
1882 Specify numerator and denomitor of the timebase assumed by the
1883 timestamps of the buffered frames.
1885 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1886 Specify numerator and denominator of the sample aspect ratio assumed
1887 by the video frames.
1890 Specify the optional parameters to be used for the scale filter which
1891 is automatically inserted when an input change is detected in the
1892 input size or format.
1897 buffer=320:240:yuv410p:1:24:1:1
1900 will instruct the source to accept video frames with size 320x240 and
1901 with format "yuv410p", assuming 1/24 as the timestamps timebase and
1902 square pixels (1:1 sample aspect ratio).
1903 Since the pixel format with name "yuv410p" corresponds to the number 6
1904 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1905 this example corresponds to:
1907 buffer=320:240:6:1:24:1:1
1912 Provide an uniformly colored input.
1914 It accepts the following parameters:
1915 @var{color}:@var{frame_size}:@var{frame_rate}
1917 Follows the description of the accepted parameters.
1922 Specify the color of the source. It can be the name of a color (case
1923 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1924 alpha specifier. The default value is "black".
1927 Specify the size of the sourced video, it may be a string of the form
1928 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1929 default value is "320x240".
1932 Specify the frame rate of the sourced video, as the number of frames
1933 generated per second. It has to be a string in the format
1934 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1935 number or a valid video frame rate abbreviation. The default value is
1940 For example the following graph description will generate a red source
1941 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1942 frames per second, which will be overlayed over the source connected
1943 to the pad with identifier "in".
1946 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1951 Read a video stream from a movie container.
1953 It accepts the syntax: @var{movie_name}[:@var{options}] where
1954 @var{movie_name} is the name of the resource to read (not necessarily
1955 a file but also a device or a stream accessed through some protocol),
1956 and @var{options} is an optional sequence of @var{key}=@var{value}
1957 pairs, separated by ":".
1959 The description of the accepted options follows.
1963 @item format_name, f
1964 Specifies the format assumed for the movie to read, and can be either
1965 the name of a container or an input device. If not specified the
1966 format is guessed from @var{movie_name} or by probing.
1968 @item seek_point, sp
1969 Specifies the seek point in seconds, the frames will be output
1970 starting from this seek point, the parameter is evaluated with
1971 @code{av_strtod} so the numerical value may be suffixed by an IS
1972 postfix. Default value is "0".
1974 @item stream_index, si
1975 Specifies the index of the video stream to read. If the value is -1,
1976 the best suited video stream will be automatically selected. Default
1981 This filter allows to overlay a second video on top of main input of
1982 a filtergraph as shown in this graph:
1984 input -----------> deltapts0 --> overlay --> output
1987 movie --> scale--> deltapts1 -------+
1990 Some examples follow:
1992 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1993 # on top of the input labelled as "in".
1994 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1995 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1997 # read from a video4linux2 device, and overlay it on top of the input
1999 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2000 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2006 Null video source, never return images. It is mainly useful as a
2007 template and to be employed in analysis / debugging tools.
2009 It accepts as optional parameter a string of the form
2010 @var{width}:@var{height}:@var{timebase}.
2012 @var{width} and @var{height} specify the size of the configured
2013 source. The default values of @var{width} and @var{height} are
2014 respectively 352 and 288 (corresponding to the CIF size format).
2016 @var{timebase} specifies an arithmetic expression representing a
2017 timebase. The expression can contain the constants "PI", "E", "PHI",
2018 "AVTB" (the default timebase), and defaults to the value "AVTB".
2022 Provide a frei0r source.
2024 To enable compilation of this filter you need to install the frei0r
2025 header and configure FFmpeg with --enable-frei0r.
2027 The source supports the syntax:
2029 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2032 @var{size} is the size of the video to generate, may be a string of the
2033 form @var{width}x@var{height} or a frame size abbreviation.
2034 @var{rate} is the rate of the video to generate, may be a string of
2035 the form @var{num}/@var{den} or a frame rate abbreviation.
2036 @var{src_name} is the name to the frei0r source to load. For more
2037 information regarding frei0r and how to set the parameters read the
2038 section @ref{frei0r} in the description of the video filters.
2040 Some examples follow:
2042 # generate a frei0r partik0l source with size 200x200 and framerate 10
2043 # which is overlayed on the overlay filter main input
2044 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2047 @section rgbtestsrc, testsrc
2049 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2050 detecting RGB vs BGR issues. You should see a red, green and blue
2051 stripe from top to bottom.
2053 The @code{testsrc} source generates a test video pattern, showing a
2054 color pattern, a scrolling gradient and a timestamp. This is mainly
2055 intended for testing purposes.
2057 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2058 separated by ":". The description of the accepted options follows.
2063 Specify the size of the sourced video, it may be a string of the form
2064 @var{width}x@var{heigth}, or the name of a size abbreviation. The
2065 default value is "320x240".
2068 Specify the frame rate of the sourced video, as the number of frames
2069 generated per second. It has to be a string in the format
2070 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2071 number or a valid video frame rate abbreviation. The default value is
2075 Set the video duration of the sourced video. The accepted syntax is:
2077 [-]HH[:MM[:SS[.m...]]]
2080 See also the function @code{av_parse_time()}.
2082 If not specified, or the expressed duration is negative, the video is
2083 supposed to be generated forever.
2086 For example the following:
2088 testsrc=duration=5.3:size=qcif:rate=10
2091 will generate a video with a duration of 5.3 seconds, with size
2092 176x144 and a framerate of 10 frames per second.
2094 @c man end VIDEO SOURCES
2096 @chapter Video Sinks
2097 @c man begin VIDEO SINKS
2099 Below is a description of the currently available video sinks.
2103 Buffer video frames, and make them available to the end of the filter
2106 This sink is mainly intended for a programmatic use, in particular
2107 through the interface defined in @file{libavfilter/vsink_buffer.h}.
2109 It does not require a string parameter in input, but you need to
2110 specify a pointer to a list of supported pixel formats terminated by
2111 -1 in the opaque parameter provided to @code{avfilter_init_filter}
2112 when initializing this sink.
2116 Null video sink, do absolutely nothing with the input video. It is
2117 mainly useful as a template and to be employed in analysis / debugging
2120 @c man end VIDEO SINKS