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 Copy the input source unchanged to the output. Mainly useful for
193 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
195 The parameters are expressions containing the following constants:
199 the corresponding mathematical approximated values for e
200 (euler number), pi (greek PI), PHI (golden ratio)
203 the computed values for @var{x} and @var{y}. They are evaluated for
207 the input width and heigth
210 same as @var{in_w} and @var{in_h}
213 the output (cropped) width and heigth
216 same as @var{out_w} and @var{out_h}
219 the number of input frame, starting from 0
222 the position in the file of the input frame, NAN if unknown
225 timestamp expressed in seconds, NAN if the input timestamp is unknown
229 The @var{out_w} and @var{out_h} parameters specify the expressions for
230 the width and height of the output (cropped) video. They are
231 evaluated just at the configuration of the filter.
233 The default value of @var{out_w} is "in_w", and the default value of
234 @var{out_h} is "in_h".
236 The expression for @var{out_w} may depend on the value of @var{out_h},
237 and the expression for @var{out_h} may depend on @var{out_w}, but they
238 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
239 evaluated after @var{out_w} and @var{out_h}.
241 The @var{x} and @var{y} parameters specify the expressions for the
242 position of the top-left corner of the output (non-cropped) area. They
243 are evaluated for each frame. If the evaluated value is not valid, it
244 is approximated to the nearest valid value.
246 The default value of @var{x} is "(in_w-out_w)/2", and the default
247 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
248 the center of the input image.
250 The expression for @var{x} may depend on @var{y}, and the expression
251 for @var{y} may depend on @var{x}.
253 Follow some examples:
255 # crop the central input area with size 100x100
258 # crop the central input area with size 2/3 of the input video
259 "crop=2/3*in_w:2/3*in_h"
261 # crop the input video central square
264 # delimit the rectangle with the top-left corner placed at position
265 # 100:100 and the right-bottom corner corresponding to the right-bottom
266 # corner of the input image.
267 crop=in_w-100:in_h-100:100:100
269 # crop 10 pixels from the left and right borders, and 20 pixels from
270 # the top and bottom borders
271 "crop=in_w-2*10:in_h-2*20"
273 # keep only the bottom right quarter of the input image
274 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
276 # crop height for getting Greek harmony
277 "crop=in_w:1/PHI*in_w"
280 "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)"
282 # erratic camera effect depending on timestamp
283 "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)"
285 # set x depending on the value of y
286 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
291 Auto-detect crop size.
293 Calculate necessary cropping parameters and prints the recommended
294 parameters through the logging system. The detected dimensions
295 correspond to the non-black area of the input video.
297 It accepts the syntax:
299 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
305 Threshold, which can be optionally specified from nothing (0) to
306 everything (255), defaults to 24.
309 Value which the width/height should be divisible by, defaults to
310 16. The offset is automatically adjusted to center the video. Use 2 to
311 get only even dimensions (needed for 4:2:2 video). 16 is best when
312 encoding to most video codecs.
315 Counter that determines after how many frames cropdetect will reset
316 the previously detected largest video area and start over to detect
317 the current optimal crop area. Defaults to 0.
319 This can be useful when channel logos distort the video area. 0
320 indicates never reset and return the largest area encountered during
326 Draw a colored box on the input image.
328 It accepts the syntax:
330 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
336 Specify the top left corner coordinates of the box. Default to 0.
339 Specify the width and height of the box, if 0 they are interpreted as
340 the input width and height. Default to 0.
343 Specify the color of the box to write, it can be the name of a color
344 (case insensitive match) or a 0xRRGGBB[AA] sequence.
347 Follow some examples:
349 # draw a black box around the edge of the input image
352 # draw a box with color red and an opacity of 50%
353 drawbox=10:20:200:60:red@@0.5"
358 Apply fade-in/out effect to input video.
360 It accepts the parameters:
361 @var{type}:@var{start_frame}:@var{nb_frames}
363 @var{type} specifies if the effect type, can be either "in" for
364 fade-in, or "out" for a fade-out effect.
366 @var{start_frame} specifies the number of the start frame for starting
367 to apply the fade effect.
369 @var{nb_frames} specifies the number of frames for which the fade
370 effect has to last. At the end of the fade-in effect the output video
371 will have the same intensity as the input video, at the end of the
372 fade-out transition the output video will be completely black.
374 A few usage examples follow, usable too as test scenarios.
376 # fade in first 30 frames of video
379 # fade out last 45 frames of a 200-frame video
382 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
383 fade=in:0:25, fade=out:975:25
385 # make first 5 frames black, then fade in from frame 5-24
391 Draw text string or text from specified file on top of video using the
394 To enable compilation of this filter you need to configure FFmpeg with
395 @code{--enable-libfreetype}.
397 The filter also recognizes strftime() sequences in the provided text
398 and expands them accordingly. Check the documentation of strftime().
400 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
403 The description of the accepted parameters follows.
408 The font file to be used for drawing text. Path must be included.
409 This parameter is mandatory.
412 The text string to be drawn. The text must be a sequence of UTF-8
414 This parameter is mandatory if no file is specified with the parameter
418 A text file containing text to be drawn. The text must be a sequence
419 of UTF-8 encoded characters.
421 This parameter is mandatory if no text string is specified with the
422 parameter @var{text}.
424 If both text and textfile are specified, an error is thrown.
427 The offsets where text will be drawn within the video frame.
428 Relative to the top/left border of the output image.
430 The default value of @var{x} and @var{y} is 0.
433 The font size to be used for drawing text.
434 The default value of @var{fontsize} is 16.
437 The color to be used for drawing fonts.
438 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
439 (e.g. "0xff000033"), possibly followed by an alpha specifier.
440 The default value of @var{fontcolor} is "black".
443 The color to be used for drawing box around text.
444 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
445 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
447 The default value of @var{bgcolor} is "white".
450 Used to draw a box around text using background color.
451 Value should be either 1 (enable) or 0 (disable).
452 The default value of @var{box} is 0.
455 Flags to be used for loading the fonts.
457 The flags map the corresponding flags supported by libfreetype, and are
458 a combination of the following values:
465 @item vertical_layout
469 @item ignore_global_advance_width
471 @item ignore_transform
478 Default value is "render".
480 For more information consult the documentation for the FT_LOAD_*
484 The size in number of spaces to use for rendering the tab.
488 For example the command:
490 drawtext="fontfile=FreeSerif.ttf: text='Test Text': x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: boxcolor=red@@0.2: box=1"
493 will draw 'Test Text' with font FreeSerif of size 24 at position
494 (100,50), text color is yellow, and draw a red box around text. Both
495 the text and the box have an opacity of 20%.
497 Note that the double quotes are not necessary if spaces are not used
498 within the parameter list.
500 For more information about libfreetype, check:
501 @url{http://www.freetype.org/}.
505 Buffer input images and send them when they are requested.
507 This filter is mainly useful when auto-inserted by the libavfilter
510 The filter does not take parameters.
514 Convert the input video to one of the specified pixel formats.
515 Libavfilter will try to pick one that is supported for the input to
518 The filter accepts a list of pixel format names, separated by ":",
519 for example "yuv420p:monow:rgb24".
521 Some examples follow:
523 # convert the input video to the format "yuv420p"
526 # convert the input video to any of the formats in the list
527 format=yuv420p:yuv444p:yuv410p
533 Apply a frei0r effect to the input video.
535 To enable compilation of this filter you need to install the frei0r
536 header and configure FFmpeg with --enable-frei0r.
538 The filter supports the syntax:
540 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
543 @var{filter_name} is the name to the frei0r effect to load. If the
544 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
545 is searched in each one of the directories specified by the colon
546 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
547 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
548 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
550 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
551 for the frei0r effect.
553 A frei0r effect parameter can be a boolean (whose values are specified
554 with "y" and "n"), a double, a color (specified by the syntax
555 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
556 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
557 description), a position (specified by the syntax @var{X}/@var{Y},
558 @var{X} and @var{Y} being float numbers) and a string.
560 The number and kind of parameters depend on the loaded effect. If an
561 effect parameter is not specified the default value is set.
563 Some examples follow:
565 # apply the distort0r effect, set the first two double parameters
566 frei0r=distort0r:0.5:0.01
568 # apply the colordistance effect, takes a color as first parameter
569 frei0r=colordistance:0.2/0.3/0.4
570 frei0r=colordistance:violet
571 frei0r=colordistance:0x112233
573 # apply the perspective effect, specify the top left and top right
575 frei0r=perspective:0.2/0.2:0.8/0.2
578 For more information see:
579 @url{http://piksel.org/frei0r}
583 Fix the banding artifacts that are sometimes introduced into nearly flat
584 regions by truncation to 8bit colordepth.
585 Interpolate the gradients that should go where the bands are, and
588 The filter takes two optional parameters, separated by ':':
589 @var{strength}:@var{radius}
591 @var{strength} is the maximum amount by which the filter will change
592 any one pixel. Also the threshold for detecting nearly flat
593 regions. Acceptable values range from .51 to 255, default value is
594 1.2, out-of-range values will be clipped to the valid range.
596 @var{radius} is the neighborhood to fit the gradient to. A larger
597 radius makes for smoother gradients, but also prevents the filter from
598 modifying the pixels near detailed regions. Acceptable values are
599 8-32, default value is 16, out-of-range values will be clipped to the
612 Flip the input video horizontally.
614 For example to horizontally flip the video in input with
617 ffmpeg -i in.avi -vf "hflip" out.avi
622 High precision/quality 3d denoise filter. This filter aims to reduce
623 image noise producing smooth images and making still images really
624 still. It should enhance compressibility.
626 It accepts the following optional parameters:
627 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
631 a non-negative float number which specifies spatial luma strength,
635 a non-negative float number which specifies spatial chroma strength,
636 defaults to 3.0*@var{luma_spatial}/4.0
639 a float number which specifies luma temporal strength, defaults to
640 6.0*@var{luma_spatial}/4.0
643 a float number which specifies chroma temporal strength, defaults to
644 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
649 Force libavfilter not to use any of the specified pixel formats for the
650 input to the next filter.
652 The filter accepts a list of pixel format names, separated by ":",
653 for example "yuv420p:monow:rgb24".
655 Some examples follow:
657 # force libavfilter to use a format different from "yuv420p" for the
658 # input to the vflip filter
659 noformat=yuv420p,vflip
661 # convert the input video to any of the formats not contained in the list
662 noformat=yuv420p:yuv444p:yuv410p
667 Pass the video source unchanged to the output.
671 Apply video transform using libopencv.
673 To enable this filter install libopencv library and headers and
674 configure FFmpeg with --enable-libopencv.
676 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
678 @var{filter_name} is the name of the libopencv filter to apply.
680 @var{filter_params} specifies the parameters to pass to the libopencv
681 filter. If not specified the default values are assumed.
683 Refer to the official libopencv documentation for more precise
685 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
687 Follows the list of supported libopencv filters.
692 Dilate an image by using a specific structuring element.
693 This filter corresponds to the libopencv function @code{cvDilate}.
695 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
697 @var{struct_el} represents a structuring element, and has the syntax:
698 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
700 @var{cols} and @var{rows} represent the number of colums and rows of
701 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
702 point, and @var{shape} the shape for the structuring element, and
703 can be one of the values "rect", "cross", "ellipse", "custom".
705 If the value for @var{shape} is "custom", it must be followed by a
706 string of the form "=@var{filename}". The file with name
707 @var{filename} is assumed to represent a binary image, with each
708 printable character corresponding to a bright pixel. When a custom
709 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
710 or columns and rows of the read file are assumed instead.
712 The default value for @var{struct_el} is "3x3+0x0/rect".
714 @var{nb_iterations} specifies the number of times the transform is
715 applied to the image, and defaults to 1.
719 # use the default values
722 # dilate using a structuring element with a 5x5 cross, iterate two times
723 ocv=dilate=5x5+2x2/cross:2
725 # read the shape from the file diamond.shape, iterate two times
726 # the file diamond.shape may contain a pattern of characters like this:
732 # the specified cols and rows are ignored (but not the anchor point coordinates)
733 ocv=0x0+2x2/custom=diamond.shape:2
738 Erode an image by using a specific structuring element.
739 This filter corresponds to the libopencv function @code{cvErode}.
741 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
742 with the same meaning and use of those of the dilate filter
747 Smooth the input video.
749 The filter takes the following parameters:
750 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
752 @var{type} is the type of smooth filter to apply, and can be one of
753 the following values: "blur", "blur_no_scale", "median", "gaussian",
754 "bilateral". The default value is "gaussian".
756 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
757 parameters whose meanings depend on smooth type. @var{param1} and
758 @var{param2} accept integer positive values or 0, @var{param3} and
759 @var{param4} accept float values.
761 The default value for @var{param1} is 3, the default value for the
762 other parameters is 0.
764 These parameters correspond to the parameters assigned to the
765 libopencv function @code{cvSmooth}.
769 Overlay one video on top of another.
771 It takes two inputs and one output, the first input is the "main"
772 video on which the second input is overlayed.
774 It accepts the parameters: @var{x}:@var{y}.
776 @var{x} is the x coordinate of the overlayed video on the main video,
777 @var{y} is the y coordinate. The parameters are expressions containing
778 the following parameters:
782 main input width and height
785 same as @var{main_w} and @var{main_h}
787 @item overlay_w, overlay_h
788 overlay input width and height
791 same as @var{overlay_w} and @var{overlay_h}
794 Be aware that frames are taken from each input video in timestamp
795 order, hence, if their initial timestamps differ, it is a a good idea
796 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
797 have them begin in the same zero timestamp, as it does the example for
798 the @var{movie} filter.
800 Follow some examples:
802 # draw the overlay at 10 pixels from the bottom right
803 # corner of the main video.
804 overlay=main_w-overlay_w-10:main_h-overlay_h-10
806 # insert a transparent PNG logo in the bottom left corner of the input
807 movie=logo.png [logo];
808 [in][logo] overlay=10:main_h-overlay_h-10 [out]
810 # insert 2 different transparent PNG logos (second logo on bottom
812 movie=logo1.png [logo1];
813 movie=logo2.png [logo2];
814 [in][logo1] overlay=10:H-h-10 [in+logo1];
815 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
817 # add a transparent color layer on top of the main video,
818 # WxH specifies the size of the main input to the overlay filter
819 color=red@.3:WxH [over]; [in][over] overlay [out]
822 You can chain togheter more overlays but the efficiency of such
823 approach is yet to be tested.
827 Add paddings to the input image, and places the original input at the
828 given coordinates @var{x}, @var{y}.
830 It accepts the following parameters:
831 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
833 Follows the description of the accepted parameters.
838 Specify the size of the output image with the paddings added. If the
839 value for @var{width} or @var{height} is 0, the corresponding input size
840 is used for the output.
842 The default value of @var{width} and @var{height} is 0.
846 Specify the offsets where to place the input image in the padded area
847 with respect to the top/left border of the output image.
849 The default value of @var{x} and @var{y} is 0.
853 Specify the color of the padded area, it can be the name of a color
854 (case insensitive match) or a 0xRRGGBB[AA] sequence.
856 The default value of @var{color} is "black".
863 # Add paddings with color "violet" to the input video. Output video
864 # size is 640x480, the top-left corner of the input video is placed at
866 pad=640:480:0:40:violet
871 Pixel format descriptor test filter, mainly useful for internal
872 testing. The output video should be equal to the input video.
876 format=monow, pixdesctest
879 can be used to test the monowhite pixel format descriptor definition.
883 Scale the input video to @var{width}:@var{height} and/or convert the image format.
885 For example the command:
888 ./ffmpeg -i in.avi -vf "scale=200:100" out.avi
891 will scale the input video to a size of 200x100.
893 If the input image format is different from the format requested by
894 the next filter, the scale filter will convert the input to the
897 If the value for @var{width} or @var{height} is 0, the respective input
898 size is used for the output.
900 If the value for @var{width} or @var{height} is -1, the scale filter will
901 use, for the respective output size, a value that maintains the aspect
902 ratio of the input image.
904 The default value of @var{width} and @var{height} is 0.
908 Change the PTS (presentation timestamp) of the input video frames.
910 Accept in input an expression evaluated through the eval API, which
911 can contain the following constants:
915 the presentation timestamp in input
927 the count of the input frame, starting from 0.
930 the PTS of the first video frame
933 tell if the current frame is interlaced
936 original position in the file of the frame, or undefined if undefined
937 for the current frame
947 Some examples follow:
950 # start counting PTS from zero
962 # fixed rate 25 fps with some jitter
963 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
968 Set the timebase to use for the output frames timestamps.
969 It is mainly useful for testing timebase configuration.
971 It accepts in input an arithmetic expression representing a rational.
972 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
973 default timebase), and "intb" (the input timebase).
975 The default value for the input is "intb".
977 Follow some examples.
980 # set the timebase to 1/25
983 # set the timebase to 1/10
986 #set the timebase to 1001/1000
989 #set the timebase to 2*intb
992 #set the default timebase value
998 Pass the images of input video on to next video filter as multiple
1002 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1005 The filter accepts the slice height as parameter. If the parameter is
1006 not specified it will use the default value of 16.
1008 Adding this in the beginning of filter chains should make filtering
1009 faster due to better use of the memory cache.
1013 Transpose rows with columns in the input video and optionally flip it.
1015 It accepts a parameter representing an integer, which can assume the
1020 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1028 Rotate by 90 degrees clockwise, that is:
1036 Rotate by 90 degrees counterclockwise, that is:
1044 Rotate by 90 degrees clockwise and vertically flip, that is:
1054 Sharpen or blur the input video.
1056 It accepts the following parameters:
1057 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1059 Negative values for the amount will blur the input video, while positive
1060 values will sharpen. All parameters are optional and default to the
1061 equivalent of the string '5:5:1.0:0:0:0.0'.
1066 Set the luma matrix horizontal size. It can be an integer between 3
1067 and 13, default value is 5.
1070 Set the luma matrix vertical size. It can be an integer between 3
1071 and 13, default value is 5.
1074 Set the luma effect strength. It can be a float number between -2.0
1075 and 5.0, default value is 1.0.
1077 @item chroma_msize_x
1078 Set the chroma matrix horizontal size. It can be an integer between 3
1079 and 13, default value is 0.
1081 @item chroma_msize_y
1082 Set the chroma matrix vertical size. It can be an integer between 3
1083 and 13, default value is 0.
1086 Set the chroma effect strength. It can be a float number between -2.0
1087 and 5.0, default value is 0.0.
1092 # Strong luma sharpen effect parameters
1095 # Strong blur of both luma and chroma parameters
1096 unsharp=7:7:-2:7:7:-2
1098 # Use the default values with @command{ffmpeg}
1099 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1104 Flip the input video vertically.
1107 ./ffmpeg -i in.avi -vf "vflip" out.avi
1112 Deinterlace the input video ("yadif" means "yet another deinterlacing
1115 It accepts the optional parameters: @var{mode}:@var{parity}.
1117 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1122 output 1 frame for each frame
1124 output 1 frame for each field
1126 like 0 but skips spatial interlacing check
1128 like 1 but skips spatial interlacing check
1133 @var{parity} specifies the picture field parity assumed for the input
1134 interlaced video, accepts one of the following values:
1138 assume bottom field first
1140 assume top field first
1142 enable automatic detection
1145 Default value is -1.
1146 If interlacing is unknown or decoder does not export this information,
1147 top field first will be assumed.
1149 @c man end VIDEO FILTERS
1151 @chapter Video Sources
1152 @c man begin VIDEO SOURCES
1154 Below is a description of the currently available video sources.
1158 Buffer video frames, and make them available to the filter chain.
1160 This source is mainly intended for a programmatic use, in particular
1161 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1163 It accepts the following parameters:
1164 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
1166 All the parameters need to be explicitely defined.
1168 Follows the list of the accepted parameters.
1173 Specify the width and height of the buffered video frames.
1175 @item pix_fmt_string
1176 A string representing the pixel format of the buffered video frames.
1177 It may be a number corresponding to a pixel format, or a pixel format
1180 @item timebase_num, timebase_den
1181 Specify numerator and denomitor of the timebase assumed by the
1182 timestamps of the buffered frames.
1184 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1185 Specify numerator and denominator of the sample aspect ratio assumed
1186 by the video frames.
1191 buffer=320:240:yuv410p:1:24:1:1
1194 will instruct the source to accept video frames with size 320x240 and
1195 with format "yuv410p", assuming 1/24 as the timestamps timebase and
1196 square pixels (1:1 sample aspect ratio).
1197 Since the pixel format with name "yuv410p" corresponds to the number 6
1198 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1199 this example corresponds to:
1201 buffer=320:240:6:1:24
1206 Provide an uniformly colored input.
1208 It accepts the following parameters:
1209 @var{color}:@var{frame_size}:@var{frame_rate}
1211 Follows the description of the accepted parameters.
1216 Specify the color of the source. It can be the name of a color (case
1217 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1218 alpha specifier. The default value is "black".
1221 Specify the size of the sourced video, it may be a string of the form
1222 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1223 default value is "320x240".
1226 Specify the frame rate of the sourced video, as the number of frames
1227 generated per second. It has to be a string in the format
1228 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1229 number or a valid video frame rate abbreviation. The default value is
1234 For example the following graph description will generate a red source
1235 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1236 frames per second, which will be overlayed over the source connected
1237 to the pad with identifier "in".
1240 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1245 Read a video stream from a movie container.
1247 It accepts the syntax: @var{movie_name}[:@var{options}] where
1248 @var{movie_name} is the name of the resource to read (not necessarily
1249 a file but also a device or a stream accessed through some protocol),
1250 and @var{options} is an optional sequence of @var{key}=@var{value}
1251 pairs, separated by ":".
1253 The description of the accepted options follows.
1257 @item format_name, f
1258 Specifies the format assumed for the movie to read, and can be either
1259 the name of a container or an input device. If not specified the
1260 format is guessed from @var{movie_name} or by probing.
1262 @item seek_point, sp
1263 Specifies the seek point in seconds, the frames will be output
1264 starting from this seek point, the parameter is evaluated with
1265 @code{av_strtod} so the numerical value may be suffixed by an IS
1266 postfix. Default value is "0".
1268 @item stream_index, si
1269 Specifies the index of the video stream to read. If the value is -1,
1270 the best suited video stream will be automatically selected. Default
1275 This filter allows to overlay a second video on top of main input of
1276 a filtergraph as shown in this graph:
1278 input -----------> deltapts0 --> overlay --> output
1281 movie --> scale--> deltapts1 -------+
1284 Some examples follow:
1286 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1287 # on top of the input labelled as "in".
1288 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1289 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1291 # read from a video4linux2 device, and overlay it on top of the input
1293 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1294 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1300 Null video source, never return images. It is mainly useful as a
1301 template and to be employed in analysis / debugging tools.
1303 It accepts as optional parameter a string of the form
1304 @var{width}:@var{height}:@var{timebase}.
1306 @var{width} and @var{height} specify the size of the configured
1307 source. The default values of @var{width} and @var{height} are
1308 respectively 352 and 288 (corresponding to the CIF size format).
1310 @var{timebase} specifies an arithmetic expression representing a
1311 timebase. The expression can contain the constants "PI", "E", "PHI",
1312 "AVTB" (the default timebase), and defaults to the value "AVTB".
1316 Provide a frei0r source.
1318 To enable compilation of this filter you need to install the frei0r
1319 header and configure FFmpeg with --enable-frei0r.
1321 The source supports the syntax:
1323 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1326 @var{size} is the size of the video to generate, may be a string of the
1327 form @var{width}x@var{height} or a frame size abbreviation.
1328 @var{rate} is the rate of the video to generate, may be a string of
1329 the form @var{num}/@var{den} or a frame rate abbreviation.
1330 @var{src_name} is the name to the frei0r source to load. For more
1331 information regarding frei0r and how to set the parameters read the
1332 section "frei0r" (@pxref{frei0r}) in the description of the video
1335 Some examples follow:
1337 # generate a frei0r partik0l source with size 200x200 and framerate 10
1338 # which is overlayed on the overlay filter main input
1339 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1342 @c man end VIDEO SOURCES
1344 @chapter Video Sinks
1345 @c man begin VIDEO SINKS
1347 Below is a description of the currently available video sinks.
1351 Null video sink, do absolutely nothing with the input video. It is
1352 mainly useful as a template and to be employed in analysis / debugging
1355 @c man end VIDEO SINKS