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{avfilter_graph_parse()} function defined in
22 @file{libavfilter/avfiltergraph.h}.
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 Convert the input audio to one of the specified formats. The framework will
105 negotiate the most appropriate format to minimize conversions.
107 The filter accepts three lists of formats, separated by ":", in the form:
108 "@var{sample_formats}:@var{channel_layouts}:@var{packing_formats}".
110 Elements in each list are separated by "," which has to be escaped in the
111 filtergraph specification.
113 The special parameter "all", in place of a list of elements, signifies all
116 Some examples follow:
118 aformat=u8\\,s16:mono:packed
120 aformat=s16:mono\\,stereo:all
125 Pass the audio source unchanged to the output.
127 @c man end AUDIO FILTERS
129 @chapter Audio Sources
130 @c man begin AUDIO SOURCES
132 Below is a description of the currently available audio sources.
136 Null audio source, never return audio frames. It is mainly useful as a
137 template and to be employed in analysis / debugging tools.
139 It accepts as optional parameter a string of the form
140 @var{sample_rate}:@var{channel_layout}.
142 @var{sample_rate} specify the sample rate, and defaults to 44100.
144 @var{channel_layout} specify the channel layout, and can be either an
145 integer or a string representing a channel layout. The default value
146 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
148 Check the channel_layout_map definition in
149 @file{libavcodec/audioconvert.c} for the mapping between strings and
150 channel layout values.
152 Follow some examples:
154 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
161 @c man end AUDIO SOURCES
164 @c man begin AUDIO SINKS
166 Below is a description of the currently available audio sinks.
170 Buffer audio frames, and make them available to the end of filter chain.
172 This sink is mainly intended for programmatic use, in particular
173 through the interface defined in @file{libavfilter/asink_abuffer.h}.
175 It requires a pointer to a ABufferSinkContext structure, which defines the
176 incoming buffers' format, to be passed as the opaque parameter to
177 @code{avfilter_init_filter} for initialization.
181 Null audio sink, do absolutely nothing with the input audio. It is
182 mainly useful as a template and to be employed in analysis / debugging
185 @c man end AUDIO SINKS
187 @chapter Video Filters
188 @c man begin VIDEO FILTERS
190 When you configure your FFmpeg build, you can disable any of the
191 existing filters using --disable-filters.
192 The configure output will show the video filters included in your
195 Below is a description of the currently available video filters.
199 Detect frames that are (almost) completely black. Can be useful to
200 detect chapter transitions or commercials. Output lines consist of
201 the frame number of the detected frame, the percentage of blackness,
202 the position in the file if known or -1 and the timestamp in seconds.
204 In order to display the output lines, you need to set the loglevel at
205 least to the AV_LOG_INFO value.
207 The filter accepts the syntax:
209 blackframe[=@var{amount}:[@var{threshold}]]
212 @var{amount} is the percentage of the pixels that have to be below the
213 threshold, and defaults to 98.
215 @var{threshold} is the threshold below which a pixel value is
216 considered black, and defaults to 32.
220 Apply boxblur algorithm to the input video.
222 This filter accepts the parameters:
223 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
225 Chroma and alpha parameters are optional, if not specified they default
226 to the corresponding values set for @var{luma_radius} and
229 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
230 the radius in pixels of the box used for blurring the corresponding
231 input plane. They are expressions, and can contain the following
235 the input width and heigth in pixels
238 the input chroma image width and height in pixels
241 horizontal and vertical chroma subsample values. For example for the
242 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
245 The radius must be a non-negative number, and must be not greater than
246 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
247 and of @code{min(cw,ch)/2} for the chroma planes.
249 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
250 how many times the boxblur filter is applied to the corresponding
253 Some examples follow:
258 Apply a boxblur filter with luma, chroma, and alpha radius
265 Set luma radius to 2, alpha and chroma radius to 0
271 Set luma and chroma radius to a fraction of the video dimension
273 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
280 Copy the input source unchanged to the output. Mainly useful for
285 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
287 The parameters are expressions containing the following constants:
291 the corresponding mathematical approximated values for e
292 (euler number), pi (greek PI), PHI (golden ratio)
295 the computed values for @var{x} and @var{y}. They are evaluated for
299 the input width and heigth
302 same as @var{in_w} and @var{in_h}
305 the output (cropped) width and heigth
308 same as @var{out_w} and @var{out_h}
311 same as @var{iw} / @var{ih}
314 input sample aspect ratio
317 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
320 horizontal and vertical chroma subsample values. For example for the
321 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
324 the number of input frame, starting from 0
327 the position in the file of the input frame, NAN if unknown
330 timestamp expressed in seconds, NAN if the input timestamp is unknown
334 The @var{out_w} and @var{out_h} parameters specify the expressions for
335 the width and height of the output (cropped) video. They are
336 evaluated just at the configuration of the filter.
338 The default value of @var{out_w} is "in_w", and the default value of
339 @var{out_h} is "in_h".
341 The expression for @var{out_w} may depend on the value of @var{out_h},
342 and the expression for @var{out_h} may depend on @var{out_w}, but they
343 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
344 evaluated after @var{out_w} and @var{out_h}.
346 The @var{x} and @var{y} parameters specify the expressions for the
347 position of the top-left corner of the output (non-cropped) area. They
348 are evaluated for each frame. If the evaluated value is not valid, it
349 is approximated to the nearest valid value.
351 The default value of @var{x} is "(in_w-out_w)/2", and the default
352 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
353 the center of the input image.
355 The expression for @var{x} may depend on @var{y}, and the expression
356 for @var{y} may depend on @var{x}.
358 Follow some examples:
360 # crop the central input area with size 100x100
363 # crop the central input area with size 2/3 of the input video
364 "crop=2/3*in_w:2/3*in_h"
366 # crop the input video central square
369 # delimit the rectangle with the top-left corner placed at position
370 # 100:100 and the right-bottom corner corresponding to the right-bottom
371 # corner of the input image.
372 crop=in_w-100:in_h-100:100:100
374 # crop 10 pixels from the left and right borders, and 20 pixels from
375 # the top and bottom borders
376 "crop=in_w-2*10:in_h-2*20"
378 # keep only the bottom right quarter of the input image
379 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
381 # crop height for getting Greek harmony
382 "crop=in_w:1/PHI*in_w"
385 "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)"
387 # erratic camera effect depending on timestamp
388 "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)"
390 # set x depending on the value of y
391 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
396 Auto-detect crop size.
398 Calculate necessary cropping parameters and prints the recommended
399 parameters through the logging system. The detected dimensions
400 correspond to the non-black area of the input video.
402 It accepts the syntax:
404 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
410 Threshold, which can be optionally specified from nothing (0) to
411 everything (255), defaults to 24.
414 Value which the width/height should be divisible by, defaults to
415 16. The offset is automatically adjusted to center the video. Use 2 to
416 get only even dimensions (needed for 4:2:2 video). 16 is best when
417 encoding to most video codecs.
420 Counter that determines after how many frames cropdetect will reset
421 the previously detected largest video area and start over to detect
422 the current optimal crop area. Defaults to 0.
424 This can be useful when channel logos distort the video area. 0
425 indicates never reset and return the largest area encountered during
431 Suppress a TV station logo by a simple interpolation of the surrounding
432 pixels. Just set a rectangle covering the logo and watch it disappear
433 (and sometimes something even uglier appear - your mileage may vary).
435 The filter accepts parameters as a string of the form
436 "@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
437 @var{key}=@var{value} pairs, separated by ":".
439 The description of the accepted parameters follows.
444 Specify the top left corner coordinates of the logo. They must be
448 Specify the width and height of the logo to clear. They must be
452 Specify the thickness of the fuzzy edge of the rectangle (added to
453 @var{w} and @var{h}). The default value is 4.
456 When set to 1, a green rectangle is drawn on the screen to simplify
457 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
458 @var{band} is set to 4. The default value is 0.
462 Some examples follow.
467 Set a rectangle covering the area with top left corner coordinates 0,0
468 and size 100x77, setting a band of size 10:
474 As the previous example, but use named options:
476 delogo=x=0:y=0:w=100:h=77:band=10
483 Draw a colored box on the input image.
485 It accepts the syntax:
487 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
493 Specify the top left corner coordinates of the box. Default to 0.
496 Specify the width and height of the box, if 0 they are interpreted as
497 the input width and height. Default to 0.
500 Specify the color of the box to write, it can be the name of a color
501 (case insensitive match) or a 0xRRGGBB[AA] sequence.
504 Follow some examples:
506 # draw a black box around the edge of the input image
509 # draw a box with color red and an opacity of 50%
510 drawbox=10:20:200:60:red@@0.5"
515 Draw text string or text from specified file on top of video using the
518 To enable compilation of this filter you need to configure FFmpeg with
519 @code{--enable-libfreetype}.
521 The filter also recognizes strftime() sequences in the provided text
522 and expands them accordingly. Check the documentation of strftime().
524 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
527 The description of the accepted parameters follows.
532 The font file to be used for drawing text. Path must be included.
533 This parameter is mandatory.
536 The text string to be drawn. The text must be a sequence of UTF-8
538 This parameter is mandatory if no file is specified with the parameter
542 A text file containing text to be drawn. The text must be a sequence
543 of UTF-8 encoded characters.
545 This parameter is mandatory if no text string is specified with the
546 parameter @var{text}.
548 If both text and textfile are specified, an error is thrown.
551 The offsets where text will be drawn within the video frame.
552 Relative to the top/left border of the output image.
554 The default value of @var{x} and @var{y} is 0.
557 The font size to be used for drawing text.
558 The default value of @var{fontsize} is 16.
561 The color to be used for drawing fonts.
562 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
563 (e.g. "0xff000033"), possibly followed by an alpha specifier.
564 The default value of @var{fontcolor} is "black".
567 The color to be used for drawing box around text.
568 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
569 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
570 The default value of @var{boxcolor} is "white".
573 Used to draw a box around text using background color.
574 Value should be either 1 (enable) or 0 (disable).
575 The default value of @var{box} is 0.
577 @item shadowx, shadowy
578 The x and y offsets for the text shadow position with respect to the
579 position of the text. They can be either positive or negative
580 values. Default value for both is "0".
583 The color to be used for drawing a shadow behind the drawn text. It
584 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
585 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
586 The default value of @var{shadowcolor} is "black".
589 Flags to be used for loading the fonts.
591 The flags map the corresponding flags supported by libfreetype, and are
592 a combination of the following values:
599 @item vertical_layout
603 @item ignore_global_advance_width
605 @item ignore_transform
612 Default value is "render".
614 For more information consult the documentation for the FT_LOAD_*
618 The size in number of spaces to use for rendering the tab.
622 For example the command:
624 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
627 will draw "Test Text" with font FreeSerif, using the default values
628 for the optional parameters.
632 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
633 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
636 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
637 and y=50 (counting from the top-left corner of the screen), text is
638 yellow with a red box around it. Both the text and the box have an
641 Note that the double quotes are not necessary if spaces are not used
642 within the parameter list.
644 For more information about libfreetype, check:
645 @url{http://www.freetype.org/}.
649 Apply fade-in/out effect to input video.
651 It accepts the parameters:
652 @var{type}:@var{start_frame}:@var{nb_frames}
654 @var{type} specifies if the effect type, can be either "in" for
655 fade-in, or "out" for a fade-out effect.
657 @var{start_frame} specifies the number of the start frame for starting
658 to apply the fade effect.
660 @var{nb_frames} specifies the number of frames for which the fade
661 effect has to last. At the end of the fade-in effect the output video
662 will have the same intensity as the input video, at the end of the
663 fade-out transition the output video will be completely black.
665 A few usage examples follow, usable too as test scenarios.
667 # fade in first 30 frames of video
670 # fade out last 45 frames of a 200-frame video
673 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
674 fade=in:0:25, fade=out:975:25
676 # make first 5 frames black, then fade in from frame 5-24
682 Transform the field order of the input video.
684 It accepts one parameter which specifies the required field order that
685 the input interlaced video will be transformed to. The parameter can
686 assume one of the following values:
690 output bottom field first
692 output top field first
695 Default value is "tff".
697 Transformation is achieved by shifting the picture content up or down
698 by one line, and filling the remaining line with appropriate picture content.
699 This method is consistent with most broadcast field order converters.
701 If the input video is not flagged as being interlaced, or it is already
702 flagged as being of the required output field order then this filter does
703 not alter the incoming video.
705 This filter is very useful when converting to or from PAL DV material,
706 which is bottom field first.
710 ./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
715 Buffer input images and send them when they are requested.
717 This filter is mainly useful when auto-inserted by the libavfilter
720 The filter does not take parameters.
724 Convert the input video to one of the specified pixel formats.
725 Libavfilter will try to pick one that is supported for the input to
728 The filter accepts a list of pixel format names, separated by ":",
729 for example "yuv420p:monow:rgb24".
731 Some examples follow:
733 # convert the input video to the format "yuv420p"
736 # convert the input video to any of the formats in the list
737 format=yuv420p:yuv444p:yuv410p
743 Apply a frei0r effect to the input video.
745 To enable compilation of this filter you need to install the frei0r
746 header and configure FFmpeg with --enable-frei0r.
748 The filter supports the syntax:
750 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
753 @var{filter_name} is the name to the frei0r effect to load. If the
754 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
755 is searched in each one of the directories specified by the colon
756 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
757 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
758 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
760 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
761 for the frei0r effect.
763 A frei0r effect parameter can be a boolean (whose values are specified
764 with "y" and "n"), a double, a color (specified by the syntax
765 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
766 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
767 description), a position (specified by the syntax @var{X}/@var{Y},
768 @var{X} and @var{Y} being float numbers) and a string.
770 The number and kind of parameters depend on the loaded effect. If an
771 effect parameter is not specified the default value is set.
773 Some examples follow:
775 # apply the distort0r effect, set the first two double parameters
776 frei0r=distort0r:0.5:0.01
778 # apply the colordistance effect, takes a color as first parameter
779 frei0r=colordistance:0.2/0.3/0.4
780 frei0r=colordistance:violet
781 frei0r=colordistance:0x112233
783 # apply the perspective effect, specify the top left and top right
785 frei0r=perspective:0.2/0.2:0.8/0.2
788 For more information see:
789 @url{http://piksel.org/frei0r}
793 Fix the banding artifacts that are sometimes introduced into nearly flat
794 regions by truncation to 8bit colordepth.
795 Interpolate the gradients that should go where the bands are, and
798 This filter is designed for playback only. Do not use it prior to
799 lossy compression, because compression tends to lose the dither and
800 bring back the bands.
802 The filter takes two optional parameters, separated by ':':
803 @var{strength}:@var{radius}
805 @var{strength} is the maximum amount by which the filter will change
806 any one pixel. Also the threshold for detecting nearly flat
807 regions. Acceptable values range from .51 to 255, default value is
808 1.2, out-of-range values will be clipped to the valid range.
810 @var{radius} is the neighborhood to fit the gradient to. A larger
811 radius makes for smoother gradients, but also prevents the filter from
812 modifying the pixels near detailed regions. Acceptable values are
813 8-32, default value is 16, out-of-range values will be clipped to the
826 Flip the input video horizontally.
828 For example to horizontally flip the video in input with
831 ffmpeg -i in.avi -vf "hflip" out.avi
836 High precision/quality 3d denoise filter. This filter aims to reduce
837 image noise producing smooth images and making still images really
838 still. It should enhance compressibility.
840 It accepts the following optional parameters:
841 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
845 a non-negative float number which specifies spatial luma strength,
849 a non-negative float number which specifies spatial chroma strength,
850 defaults to 3.0*@var{luma_spatial}/4.0
853 a float number which specifies luma temporal strength, defaults to
854 6.0*@var{luma_spatial}/4.0
857 a float number which specifies chroma temporal strength, defaults to
858 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
861 @section lut, lutrgb, lutyuv
863 Compute a look-up table for binding each pixel component input value
864 to an output value, and apply it to input video.
866 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
867 to an RGB input video.
869 These filters accept in input a ":"-separated list of options, which
870 specify the expressions used for computing the lookup table for the
871 corresponding pixel component values.
873 The @var{lut} filter requires either YUV or RGB pixel formats in
874 input, and accepts the options:
876 @var{c0} (first pixel component)
877 @var{c1} (second pixel component)
878 @var{c2} (third pixel component)
879 @var{c3} (fourth pixel component, corresponds to the alpha component)
882 The exact component associated to each option depends on the format in
885 The @var{lutrgb} filter requires RGB pixel formats in input, and
888 @var{r} (red component)
889 @var{g} (green component)
890 @var{b} (blue component)
891 @var{a} (alpha component)
894 The @var{lutyuv} filter requires YUV pixel formats in input, and
897 @var{y} (Y/luminance component)
898 @var{u} (U/Cb component)
899 @var{v} (V/Cr component)
900 @var{a} (alpha component)
903 The expressions can contain the following constants and functions:
907 the corresponding mathematical approximated values for e
908 (euler number), pi (greek PI), PHI (golden ratio)
911 the input width and heigth
914 input value for the pixel component
917 the input value clipped in the @var{minval}-@var{maxval} range
920 maximum value for the pixel component
923 minimum value for the pixel component
926 the negated value for the pixel component value clipped in the
927 @var{minval}-@var{maxval} range , it corresponds to the expression
928 "maxval-clipval+minval"
931 the computed value in @var{val} clipped in the
932 @var{minval}-@var{maxval} range
934 @item gammaval(gamma)
935 the computed gamma correction value of the pixel component value
936 clipped in the @var{minval}-@var{maxval} range, corresponds to the
938 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
942 All expressions default to "val".
944 Some examples follow:
947 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
948 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
950 # the above is the same as
951 lutrgb="r=negval:g=negval:b=negval"
952 lutyuv="y=negval:u=negval:v=negval"
957 # remove chroma components, turns the video into a graytone image
960 # apply a luma burning effect
963 # remove green and blue components
966 # set a constant alpha channel value on input
967 format=rgba,lutrgb=a="maxval-minval/2"
969 # correct luminance gamma by a 0.5 factor
970 lutyuv=y=gammaval(0.5)
975 Apply an MPlayer filter to the input video.
977 This filter provides a wrapper around most of the filters of
980 This wrapper is considered experimental. Some of the wrapped filters
981 may not work properly and we may drop support for them, as they will
982 be implemented natively into FFmpeg. Thus you should avoid
983 depending on them when writing portable scripts.
985 The filters accepts the parameters:
986 @var{filter_name}[:=]@var{filter_params}
988 @var{filter_name} is the name of a supported MPlayer filter,
989 @var{filter_params} is a string containing the parameters accepted by
992 The list of the currently supported filters follows:
1046 The parameter syntax and behavior for the listed filters are the same
1047 of the corresponding MPlayer filters. For detailed instructions check
1048 the "VIDEO FILTERS" section in the MPlayer manual.
1050 Some examples follow:
1052 # remove a logo by interpolating the surrounding pixels
1053 mp=delogo=200:200:80:20:1
1055 # adjust gamma, brightness, contrast
1058 # tweak hue and saturation
1062 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
1068 This filter accepts an integer in input, if non-zero it negates the
1069 alpha component (if available). The default value in input is 0.
1073 Force libavfilter not to use any of the specified pixel formats for the
1074 input to the next filter.
1076 The filter accepts a list of pixel format names, separated by ":",
1077 for example "yuv420p:monow:rgb24".
1079 Some examples follow:
1081 # force libavfilter to use a format different from "yuv420p" for the
1082 # input to the vflip filter
1083 noformat=yuv420p,vflip
1085 # convert the input video to any of the formats not contained in the list
1086 noformat=yuv420p:yuv444p:yuv410p
1091 Pass the video source unchanged to the output.
1095 Apply video transform using libopencv.
1097 To enable this filter install libopencv library and headers and
1098 configure FFmpeg with --enable-libopencv.
1100 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1102 @var{filter_name} is the name of the libopencv filter to apply.
1104 @var{filter_params} specifies the parameters to pass to the libopencv
1105 filter. If not specified the default values are assumed.
1107 Refer to the official libopencv documentation for more precise
1109 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1111 Follows the list of supported libopencv filters.
1116 Dilate an image by using a specific structuring element.
1117 This filter corresponds to the libopencv function @code{cvDilate}.
1119 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1121 @var{struct_el} represents a structuring element, and has the syntax:
1122 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1124 @var{cols} and @var{rows} represent the number of colums and rows of
1125 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1126 point, and @var{shape} the shape for the structuring element, and
1127 can be one of the values "rect", "cross", "ellipse", "custom".
1129 If the value for @var{shape} is "custom", it must be followed by a
1130 string of the form "=@var{filename}". The file with name
1131 @var{filename} is assumed to represent a binary image, with each
1132 printable character corresponding to a bright pixel. When a custom
1133 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1134 or columns and rows of the read file are assumed instead.
1136 The default value for @var{struct_el} is "3x3+0x0/rect".
1138 @var{nb_iterations} specifies the number of times the transform is
1139 applied to the image, and defaults to 1.
1141 Follow some example:
1143 # use the default values
1146 # dilate using a structuring element with a 5x5 cross, iterate two times
1147 ocv=dilate=5x5+2x2/cross:2
1149 # read the shape from the file diamond.shape, iterate two times
1150 # the file diamond.shape may contain a pattern of characters like this:
1156 # the specified cols and rows are ignored (but not the anchor point coordinates)
1157 ocv=0x0+2x2/custom=diamond.shape:2
1162 Erode an image by using a specific structuring element.
1163 This filter corresponds to the libopencv function @code{cvErode}.
1165 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1166 with the same syntax and semantics as the @ref{dilate} filter.
1170 Smooth the input video.
1172 The filter takes the following parameters:
1173 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1175 @var{type} is the type of smooth filter to apply, and can be one of
1176 the following values: "blur", "blur_no_scale", "median", "gaussian",
1177 "bilateral". The default value is "gaussian".
1179 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1180 parameters whose meanings depend on smooth type. @var{param1} and
1181 @var{param2} accept integer positive values or 0, @var{param3} and
1182 @var{param4} accept float values.
1184 The default value for @var{param1} is 3, the default value for the
1185 other parameters is 0.
1187 These parameters correspond to the parameters assigned to the
1188 libopencv function @code{cvSmooth}.
1192 Overlay one video on top of another.
1194 It takes two inputs and one output, the first input is the "main"
1195 video on which the second input is overlayed.
1197 It accepts the parameters: @var{x}:@var{y}.
1199 @var{x} is the x coordinate of the overlayed video on the main video,
1200 @var{y} is the y coordinate. The parameters are expressions containing
1201 the following parameters:
1204 @item main_w, main_h
1205 main input width and height
1208 same as @var{main_w} and @var{main_h}
1210 @item overlay_w, overlay_h
1211 overlay input width and height
1214 same as @var{overlay_w} and @var{overlay_h}
1217 Be aware that frames are taken from each input video in timestamp
1218 order, hence, if their initial timestamps differ, it is a a good idea
1219 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1220 have them begin in the same zero timestamp, as it does the example for
1221 the @var{movie} filter.
1223 Follow some examples:
1225 # draw the overlay at 10 pixels from the bottom right
1226 # corner of the main video.
1227 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1229 # insert a transparent PNG logo in the bottom left corner of the input
1230 movie=logo.png [logo];
1231 [in][logo] overlay=10:main_h-overlay_h-10 [out]
1233 # insert 2 different transparent PNG logos (second logo on bottom
1235 movie=logo1.png [logo1];
1236 movie=logo2.png [logo2];
1237 [in][logo1] overlay=10:H-h-10 [in+logo1];
1238 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
1240 # add a transparent color layer on top of the main video,
1241 # WxH specifies the size of the main input to the overlay filter
1242 color=red@.3:WxH [over]; [in][over] overlay [out]
1245 You can chain togheter more overlays but the efficiency of such
1246 approach is yet to be tested.
1250 Add paddings to the input image, and places the original input at the
1251 given coordinates @var{x}, @var{y}.
1253 It accepts the following parameters:
1254 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1256 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1257 expressions containing the following constants:
1261 the corresponding mathematical approximated values for e
1262 (euler number), pi (greek PI), phi (golden ratio)
1265 the input video width and heigth
1268 same as @var{in_w} and @var{in_h}
1271 the output width and heigth, that is the size of the padded area as
1272 specified by the @var{width} and @var{height} expressions
1275 same as @var{out_w} and @var{out_h}
1278 x and y offsets as specified by the @var{x} and @var{y}
1279 expressions, or NAN if not yet specified
1282 same as @var{iw} / @var{ih}
1285 input sample aspect ratio
1288 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1291 horizontal and vertical chroma subsample values. For example for the
1292 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1295 Follows the description of the accepted parameters.
1300 Specify the size of the output image with the paddings added. If the
1301 value for @var{width} or @var{height} is 0, the corresponding input size
1302 is used for the output.
1304 The @var{width} expression can reference the value set by the
1305 @var{height} expression, and viceversa.
1307 The default value of @var{width} and @var{height} is 0.
1311 Specify the offsets where to place the input image in the padded area
1312 with respect to the top/left border of the output image.
1314 The @var{x} expression can reference the value set by the @var{y}
1315 expression, and viceversa.
1317 The default value of @var{x} and @var{y} is 0.
1321 Specify the color of the padded area, it can be the name of a color
1322 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1324 The default value of @var{color} is "black".
1328 Some examples follow:
1331 # Add paddings with color "violet" to the input video. Output video
1332 # size is 640x480, the top-left corner of the input video is placed at
1334 pad=640:480:0:40:violet
1336 # pad the input to get an output with dimensions increased bt 3/2,
1337 # and put the input video at the center of the padded area
1338 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1340 # pad the input to get a squared output with size equal to the maximum
1341 # value between the input width and height, and put the input video at
1342 # the center of the padded area
1343 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1345 # pad the input to get a final w/h ratio of 16:9
1346 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1348 # for anamorphic video, in order to set the output display aspect ratio,
1349 # it is necessary to use sar in the expression, according to the relation:
1350 # (ih * X / ih) * sar = output_dar
1351 # X = output_dar / sar
1352 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
1354 # double output size and put the input video in the bottom-right
1355 # corner of the output padded area
1356 pad="2*iw:2*ih:ow-iw:oh-ih"
1359 @section pixdesctest
1361 Pixel format descriptor test filter, mainly useful for internal
1362 testing. The output video should be equal to the input video.
1366 format=monow, pixdesctest
1369 can be used to test the monowhite pixel format descriptor definition.
1373 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1375 The parameters @var{width} and @var{height} are expressions containing
1376 the following constants:
1380 the corresponding mathematical approximated values for e
1381 (euler number), pi (greek PI), phi (golden ratio)
1384 the input width and heigth
1387 same as @var{in_w} and @var{in_h}
1390 the output (cropped) width and heigth
1393 same as @var{out_w} and @var{out_h}
1396 same as @var{iw} / @var{ih}
1399 input sample aspect ratio
1402 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1405 horizontal and vertical chroma subsample values. For example for the
1406 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1409 If the input image format is different from the format requested by
1410 the next filter, the scale filter will convert the input to the
1413 If the value for @var{width} or @var{height} is 0, the respective input
1414 size is used for the output.
1416 If the value for @var{width} or @var{height} is -1, the scale filter will
1417 use, for the respective output size, a value that maintains the aspect
1418 ratio of the input image.
1420 The default value of @var{width} and @var{height} is 0.
1422 Some examples follow:
1424 # scale the input video to a size of 200x100.
1427 # scale the input to 2x
1429 # the above is the same as
1432 # scale the input to half size
1435 # increase the width, and set the height to the same size
1438 # seek for Greek harmony
1442 # increase the height, and set the width to 3/2 of the height
1445 # increase the size, but make the size a multiple of the chroma
1446 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1448 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1449 scale='min(500\, iw*3/2):-1'
1453 Select frames to pass in output.
1455 It accepts in input an expression, which is evaluated for each input
1456 frame. If the expression is evaluated to a non-zero value, the frame
1457 is selected and passed to the output, otherwise it is discarded.
1459 The expression can contain the following constants:
1472 the sequential number of the filtered frame, starting from 0
1475 the sequential number of the selected frame, starting from 0
1477 @item prev_selected_n
1478 the sequential number of the last selected frame, NAN if undefined
1481 timebase of the input timestamps
1484 the PTS (Presentation TimeStamp) of the filtered video frame,
1485 expressed in @var{TB} units, NAN if undefined
1488 the PTS (Presentation TimeStamp) of the filtered video frame,
1489 expressed in seconds, NAN if undefined
1492 the PTS of the previously filtered video frame, NAN if undefined
1494 @item prev_selected_pts
1495 the PTS of the last previously filtered video frame, NAN if undefined
1497 @item prev_selected_t
1498 the PTS of the last previously selected video frame, NAN if undefined
1501 the PTS of the first video frame in the video, NAN if undefined
1504 the time of the first video frame in the video, NAN if undefined
1507 the picture type of the filtered frame, can assume one of the following
1519 @item interlace_type
1520 the frame interlace type, can assume one of the following values:
1522 @item INTERLACE_TYPE_P
1523 the frame is progressive (not interlaced)
1524 @item INTERLACE_TYPE_T
1525 the frame is top-field-first
1526 @item INTERLACE_TYPE_B
1527 the frame is bottom-field-first
1531 1 if the filtered frame is a key-frame, 0 otherwise
1534 the position in the file of the filtered frame, -1 if the information
1535 is not available (e.g. for synthetic video)
1538 The default value of the select expression is "1".
1540 Some examples follow:
1543 # select all frames in input
1546 # the above is the same as:
1552 # select only I-frames
1553 select='eq(pict_type\,PICT_TYPE_I)'
1555 # select one frame every 100
1556 select='not(mod(n\,100))'
1558 # select only frames contained in the 10-20 time interval
1559 select='gte(t\,10)*lte(t\,20)'
1561 # select only I frames contained in the 10-20 time interval
1562 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,PICT_TYPE_I)'
1564 # select frames with a minimum distance of 10 seconds
1565 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1571 Set the Display Aspect Ratio for the filter output video.
1573 This is done by changing the specified Sample (aka Pixel) Aspect
1574 Ratio, according to the following equation:
1575 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1577 Keep in mind that this filter does not modify the pixel dimensions of
1578 the video frame. Also the display aspect ratio set by this filter may
1579 be changed by later filters in the filterchain, e.g. in case of
1580 scaling or if another "setdar" or a "setsar" filter is applied.
1582 The filter accepts a parameter string which represents the wanted
1583 display aspect ratio.
1584 The parameter can be a floating point number string, or an expression
1585 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1586 numerator and denominator of the aspect ratio.
1587 If the parameter is not specified, it is assumed the value "0:1".
1589 For example to change the display aspect ratio to 16:9, specify:
1592 # the above is equivalent to
1596 See also the @ref{setsar} filter documentation.
1600 Change the PTS (presentation timestamp) of the input video frames.
1602 Accept in input an expression evaluated through the eval API, which
1603 can contain the following constants:
1607 the presentation timestamp in input
1619 the count of the input frame, starting from 0.
1622 the PTS of the first video frame
1625 tell if the current frame is interlaced
1628 original position in the file of the frame, or undefined if undefined
1629 for the current frame
1639 Some examples follow:
1642 # start counting PTS from zero
1654 # fixed rate 25 fps with some jitter
1655 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1661 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1663 Note that as a consequence of the application of this filter, the
1664 output display aspect ratio will change according to the following
1666 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1668 Keep in mind that the sample aspect ratio set by this filter may be
1669 changed by later filters in the filterchain, e.g. if another "setsar"
1670 or a "setdar" filter is applied.
1672 The filter accepts a parameter string which represents the wanted
1673 sample aspect ratio.
1674 The parameter can be a floating point number string, or an expression
1675 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1676 numerator and denominator of the aspect ratio.
1677 If the parameter is not specified, it is assumed the value "0:1".
1679 For example to change the sample aspect ratio to 10:11, specify:
1686 Set the timebase to use for the output frames timestamps.
1687 It is mainly useful for testing timebase configuration.
1689 It accepts in input an arithmetic expression representing a rational.
1690 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1691 default timebase), and "intb" (the input timebase).
1693 The default value for the input is "intb".
1695 Follow some examples.
1698 # set the timebase to 1/25
1701 # set the timebase to 1/10
1704 #set the timebase to 1001/1000
1707 #set the timebase to 2*intb
1710 #set the default timebase value
1716 Show a line containing various information for each input video frame.
1717 The input video is not modified.
1719 The shown line contains a sequence of key/value pairs of the form
1720 @var{key}:@var{value}.
1722 A description of each shown parameter follows:
1726 sequential number of the input frame, starting from 0
1729 Presentation TimeStamp of the input frame, expressed as a number of
1730 time base units. The time base unit depends on the filter input pad.
1733 Presentation TimeStamp of the input frame, expressed as a number of
1737 position of the frame in the input stream, -1 if this information in
1738 unavailable and/or meanigless (for example in case of synthetic video)
1744 sample aspect ratio of the input frame, expressed in the form
1748 size of the input frame, expressed in the form
1749 @var{width}x@var{height}
1752 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1753 for bottom field first)
1756 1 if the frame is a key frame, 0 otherwise
1759 picture type of the input frame ("I" for an I-frame, "P" for a
1760 P-frame, "B" for a B-frame, "?" for unknown type).
1761 Check also the documentation of the @code{AVPictureType} enum and of
1762 the @code{av_get_picture_type_char} function defined in
1763 @file{libavutil/avutil.h}.
1766 Adler-32 checksum of all the planes of the input frame
1768 @item plane_checksum
1769 Adler-32 checksum of each plane of the input frame, expressed in the form
1770 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
1775 Pass the images of input video on to next video filter as multiple
1779 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1782 The filter accepts the slice height as parameter. If the parameter is
1783 not specified it will use the default value of 16.
1785 Adding this in the beginning of filter chains should make filtering
1786 faster due to better use of the memory cache.
1790 Pass on the input video to two outputs. Both outputs are identical to
1795 [in] split [splitout1][splitout2];
1796 [splitout1] crop=100:100:0:0 [cropout];
1797 [splitout2] pad=200:200:100:100 [padout];
1800 will create two separate outputs from the same input, one cropped and
1805 Transpose rows with columns in the input video and optionally flip it.
1807 It accepts a parameter representing an integer, which can assume the
1812 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1820 Rotate by 90 degrees clockwise, that is:
1828 Rotate by 90 degrees counterclockwise, that is:
1836 Rotate by 90 degrees clockwise and vertically flip, that is:
1846 Sharpen or blur the input video.
1848 It accepts the following parameters:
1849 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1851 Negative values for the amount will blur the input video, while positive
1852 values will sharpen. All parameters are optional and default to the
1853 equivalent of the string '5:5:1.0:0:0:0.0'.
1858 Set the luma matrix horizontal size. It can be an integer between 3
1859 and 13, default value is 5.
1862 Set the luma matrix vertical size. It can be an integer between 3
1863 and 13, default value is 5.
1866 Set the luma effect strength. It can be a float number between -2.0
1867 and 5.0, default value is 1.0.
1869 @item chroma_msize_x
1870 Set the chroma matrix horizontal size. It can be an integer between 3
1871 and 13, default value is 0.
1873 @item chroma_msize_y
1874 Set the chroma matrix vertical size. It can be an integer between 3
1875 and 13, default value is 0.
1878 Set the chroma effect strength. It can be a float number between -2.0
1879 and 5.0, default value is 0.0.
1884 # Strong luma sharpen effect parameters
1887 # Strong blur of both luma and chroma parameters
1888 unsharp=7:7:-2:7:7:-2
1890 # Use the default values with @command{ffmpeg}
1891 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1896 Flip the input video vertically.
1899 ./ffmpeg -i in.avi -vf "vflip" out.avi
1904 Deinterlace the input video ("yadif" means "yet another deinterlacing
1907 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
1909 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1914 output 1 frame for each frame
1916 output 1 frame for each field
1918 like 0 but skips spatial interlacing check
1920 like 1 but skips spatial interlacing check
1925 @var{parity} specifies the picture field parity assumed for the input
1926 interlaced video, accepts one of the following values:
1930 assume top field first
1932 assume bottom field first
1934 enable automatic detection
1937 Default value is -1.
1938 If interlacing is unknown or decoder does not export this information,
1939 top field first will be assumed.
1941 @var{auto} specifies if deinterlacer should trust the interlaced flag
1942 and only deinterlace frames marked as interlaced
1946 deinterlace all frames
1948 only deinterlace frames marked as interlaced
1953 @c man end VIDEO FILTERS
1955 @chapter Video Sources
1956 @c man begin VIDEO SOURCES
1958 Below is a description of the currently available video sources.
1962 Buffer video frames, and make them available to the filter chain.
1964 This source is mainly intended for a programmatic use, in particular
1965 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1967 It accepts the following parameters:
1968 @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}
1970 All the parameters but @var{scale_params} need to be explicitely
1973 Follows the list of the accepted parameters.
1978 Specify the width and height of the buffered video frames.
1980 @item pix_fmt_string
1981 A string representing the pixel format of the buffered video frames.
1982 It may be a number corresponding to a pixel format, or a pixel format
1985 @item timebase_num, timebase_den
1986 Specify numerator and denomitor of the timebase assumed by the
1987 timestamps of the buffered frames.
1989 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1990 Specify numerator and denominator of the sample aspect ratio assumed
1991 by the video frames.
1994 Specify the optional parameters to be used for the scale filter which
1995 is automatically inserted when an input change is detected in the
1996 input size or format.
2001 buffer=320:240:yuv410p:1:24:1:1
2004 will instruct the source to accept video frames with size 320x240 and
2005 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2006 square pixels (1:1 sample aspect ratio).
2007 Since the pixel format with name "yuv410p" corresponds to the number 6
2008 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
2009 this example corresponds to:
2011 buffer=320:240:6:1:24:1:1
2016 Provide an uniformly colored input.
2018 It accepts the following parameters:
2019 @var{color}:@var{frame_size}:@var{frame_rate}
2021 Follows the description of the accepted parameters.
2026 Specify the color of the source. It can be the name of a color (case
2027 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2028 alpha specifier. The default value is "black".
2031 Specify the size of the sourced video, it may be a string of the form
2032 @var{width}x@var{heigth}, or the name of a size abbreviation. The
2033 default value is "320x240".
2036 Specify the frame rate of the sourced video, as the number of frames
2037 generated per second. It has to be a string in the format
2038 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2039 number or a valid video frame rate abbreviation. The default value is
2044 For example the following graph description will generate a red source
2045 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2046 frames per second, which will be overlayed over the source connected
2047 to the pad with identifier "in".
2050 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2055 Read a video stream from a movie container.
2057 It accepts the syntax: @var{movie_name}[:@var{options}] where
2058 @var{movie_name} is the name of the resource to read (not necessarily
2059 a file but also a device or a stream accessed through some protocol),
2060 and @var{options} is an optional sequence of @var{key}=@var{value}
2061 pairs, separated by ":".
2063 The description of the accepted options follows.
2067 @item format_name, f
2068 Specifies the format assumed for the movie to read, and can be either
2069 the name of a container or an input device. If not specified the
2070 format is guessed from @var{movie_name} or by probing.
2072 @item seek_point, sp
2073 Specifies the seek point in seconds, the frames will be output
2074 starting from this seek point, the parameter is evaluated with
2075 @code{av_strtod} so the numerical value may be suffixed by an IS
2076 postfix. Default value is "0".
2078 @item stream_index, si
2079 Specifies the index of the video stream to read. If the value is -1,
2080 the best suited video stream will be automatically selected. Default
2085 This filter allows to overlay a second video on top of main input of
2086 a filtergraph as shown in this graph:
2088 input -----------> deltapts0 --> overlay --> output
2091 movie --> scale--> deltapts1 -------+
2094 Some examples follow:
2096 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2097 # on top of the input labelled as "in".
2098 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2099 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2101 # read from a video4linux2 device, and overlay it on top of the input
2103 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2104 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2110 Generate various test patterns, as generated by the MPlayer test filter.
2112 The size of the generated video is fixed, and is 256x256.
2113 This source is useful in particular for testing encoding features.
2115 This source accepts an optional sequence of @var{key}=@var{value} pairs,
2116 separated by ":". The description of the accepted options follows.
2121 Specify the frame rate of the sourced video, as the number of frames
2122 generated per second. It has to be a string in the format
2123 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2124 number or a valid video frame rate abbreviation. The default value is
2128 Set the video duration of the sourced video. The accepted syntax is:
2130 [-]HH[:MM[:SS[.m...]]]
2133 See also the function @code{av_parse_time()}.
2135 If not specified, or the expressed duration is negative, the video is
2136 supposed to be generated forever.
2140 Set the number or the name of the test to perform. Supported tests are:
2155 Default value is "all", which will cycle through the list of all tests.
2158 For example the following:
2163 will generate a "dc_luma" test pattern.
2167 Null video source, never return images. It is mainly useful as a
2168 template and to be employed in analysis / debugging tools.
2170 It accepts as optional parameter a string of the form
2171 @var{width}:@var{height}:@var{timebase}.
2173 @var{width} and @var{height} specify the size of the configured
2174 source. The default values of @var{width} and @var{height} are
2175 respectively 352 and 288 (corresponding to the CIF size format).
2177 @var{timebase} specifies an arithmetic expression representing a
2178 timebase. The expression can contain the constants "PI", "E", "PHI",
2179 "AVTB" (the default timebase), and defaults to the value "AVTB".
2183 Provide a frei0r source.
2185 To enable compilation of this filter you need to install the frei0r
2186 header and configure FFmpeg with --enable-frei0r.
2188 The source supports the syntax:
2190 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2193 @var{size} is the size of the video to generate, may be a string of the
2194 form @var{width}x@var{height} or a frame size abbreviation.
2195 @var{rate} is the rate of the video to generate, may be a string of
2196 the form @var{num}/@var{den} or a frame rate abbreviation.
2197 @var{src_name} is the name to the frei0r source to load. For more
2198 information regarding frei0r and how to set the parameters read the
2199 section @ref{frei0r} in the description of the video filters.
2201 Some examples follow:
2203 # generate a frei0r partik0l source with size 200x200 and framerate 10
2204 # which is overlayed on the overlay filter main input
2205 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2208 @section rgbtestsrc, testsrc
2210 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2211 detecting RGB vs BGR issues. You should see a red, green and blue
2212 stripe from top to bottom.
2214 The @code{testsrc} source generates a test video pattern, showing a
2215 color pattern, a scrolling gradient and a timestamp. This is mainly
2216 intended for testing purposes.
2218 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2219 separated by ":". The description of the accepted options follows.
2224 Specify the size of the sourced video, it may be a string of the form
2225 @var{width}x@var{heigth}, or the name of a size abbreviation. The
2226 default value is "320x240".
2229 Specify the frame rate of the sourced video, as the number of frames
2230 generated per second. It has to be a string in the format
2231 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2232 number or a valid video frame rate abbreviation. The default value is
2236 Set the video duration of the sourced video. The accepted syntax is:
2238 [-]HH[:MM[:SS[.m...]]]
2241 See also the function @code{av_parse_time()}.
2243 If not specified, or the expressed duration is negative, the video is
2244 supposed to be generated forever.
2247 For example the following:
2249 testsrc=duration=5.3:size=qcif:rate=10
2252 will generate a video with a duration of 5.3 seconds, with size
2253 176x144 and a framerate of 10 frames per second.
2255 @c man end VIDEO SOURCES
2257 @chapter Video Sinks
2258 @c man begin VIDEO SINKS
2260 Below is a description of the currently available video sinks.
2264 Buffer video frames, and make them available to the end of the filter
2267 This sink is mainly intended for a programmatic use, in particular
2268 through the interface defined in @file{libavfilter/vsink_buffer.h}.
2270 It does not require a string parameter in input, but you need to
2271 specify a pointer to a list of supported pixel formats terminated by
2272 -1 in the opaque parameter provided to @code{avfilter_init_filter}
2273 when initializing this sink.
2277 Null video sink, do absolutely nothing with the input video. It is
2278 mainly useful as a template and to be employed in analysis / debugging
2281 @c man end VIDEO SINKS