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.
417 A text file containing text to be drawn. The text must be a sequence
418 of UTF-8 encoded characters
420 This parameter is mandatory if no text string is specified.
422 If both text and textfile are specified, an error is thrown.
425 The offsets where text will be drawn within the video frame.
426 Relative to the top/left border of the output image.
428 The default value of @var{x} and @var{y} is 0.
431 The font size to be used for drawing text.
432 The default value of @var{size} is 16.
435 The color to be used for drawing fonts.
436 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
437 (e.g. "0xff000033"), possibly followed by an alpha specifier.
438 The default value of @var{fontcolor} is "black".
441 The color to be used for drawing box around text.
442 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
443 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
445 The default value of @var{bgcolor} is "white".
448 Used to draw a box around text using background color.
449 Value should be either 1 (enable) or 0 (disable).
450 The default value of @var{box} is 0.
453 Flags to be used for loading the fonts.
455 The flags map the corresponding flags supported by libfreetype, and are
456 a combination of the following values:
463 @item vertical_layout
467 @item ignore_global_advance_width
469 @item ignore_transform
476 Default value is "render".
478 For more information consult the documentation for the FT_LOAD_*
482 The size in number of spaces to use for rendering the tab.
486 For example the command:
488 drawtext=fontfile=FreeSerif.ttf: text='Test Text': x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: boxcolor=red@@0.2: box=1"
491 will draw 'Test Text' with font FreeSerif of size 24 at position
492 (100,50), text color is yellow, and draw a red box around text. Both
493 the text and the box have an opacity of 20%.
495 Note that the double quotes are not necessary if spaces are not used
496 within the parameter list.
498 For more information about libfreetype, check:
499 @url{http://www.freetype.org/}
503 Buffer input images and send them when they are requested.
505 This filter is mainly useful when auto-inserted by the libavfilter
508 The filter does not take parameters.
512 Convert the input video to one of the specified pixel formats.
513 Libavfilter will try to pick one that is supported for the input to
516 The filter accepts a list of pixel format names, separated by ":",
517 for example "yuv420p:monow:rgb24".
519 Some examples follow:
521 # convert the input video to the format "yuv420p"
524 # convert the input video to any of the formats in the list
525 format=yuv420p:yuv444p:yuv410p
531 Apply a frei0r effect to the input video.
533 To enable compilation of this filter you need to install the frei0r
534 header and configure FFmpeg with --enable-frei0r.
536 The filter supports the syntax:
538 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
541 @var{filter_name} is the name to the frei0r effect to load. If the
542 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
543 is searched in each one of the directories specified by the colon
544 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
545 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
546 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
548 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
549 for the frei0r effect.
551 A frei0r effect parameter can be a boolean (whose values are specified
552 with "y" and "n"), a double, a color (specified by the syntax
553 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
554 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
555 description), a position (specified by the syntax @var{X}/@var{Y},
556 @var{X} and @var{Y} being float numbers) and a string.
558 The number and kind of parameters depend on the loaded effect. If an
559 effect parameter is not specified the default value is set.
561 Some examples follow:
563 # apply the distort0r effect, set the first two double parameters
564 frei0r=distort0r:0.5:0.01
566 # apply the colordistance effect, takes a color as first parameter
567 frei0r=colordistance:0.2/0.3/0.4
568 frei0r=colordistance:violet
569 frei0r=colordistance:0x112233
571 # apply the perspective effect, specify the top left and top right
573 frei0r=perspective:0.2/0.2:0.8/0.2
576 For more information see:
577 @url{http://piksel.org/frei0r}
581 Fix the banding artifacts that are sometimes introduced into nearly flat
582 regions by truncation to 8bit colordepth.
583 Interpolate the gradients that should go where the bands are, and
586 The filter takes two optional parameters, separated by ':':
587 @var{strength}:@var{radius}
589 @var{strength} is the maximum amount by which the filter will change
590 any one pixel. Also the threshold for detecting nearly flat
591 regions. Acceptable values range from .51 to 255, default value is
592 1.2, out-of-range values will be clipped to the valid range.
594 @var{radius} is the neighborhood to fit the gradient to. A larger
595 radius makes for smoother gradients, but also prevents the filter from
596 modifying the pixels near detailed regions. Acceptable values are
597 8-32, default value is 16, out-of-range values will be clipped to the
610 Flip the input video horizontally.
612 For example to horizontally flip the video in input with
615 ffmpeg -i in.avi -vf "hflip" out.avi
620 High precision/quality 3d denoise filter. This filter aims to reduce
621 image noise producing smooth images and making still images really
622 still. It should enhance compressibility.
624 It accepts the following optional parameters:
625 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
629 a non-negative float number which specifies spatial luma strength,
633 a non-negative float number which specifies spatial chroma strength,
634 defaults to 3.0*@var{luma_spatial}/4.0
637 a float number which specifies luma temporal strength, defaults to
638 6.0*@var{luma_spatial}/4.0
641 a float number which specifies chroma temporal strength, defaults to
642 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
647 Force libavfilter not to use any of the specified pixel formats for the
648 input to the next filter.
650 The filter accepts a list of pixel format names, separated by ":",
651 for example "yuv420p:monow:rgb24".
653 Some examples follow:
655 # force libavfilter to use a format different from "yuv420p" for the
656 # input to the vflip filter
657 noformat=yuv420p,vflip
659 # convert the input video to any of the formats not contained in the list
660 noformat=yuv420p:yuv444p:yuv410p
665 Pass the video source unchanged to the output.
669 Apply video transform using libopencv.
671 To enable this filter install libopencv library and headers and
672 configure FFmpeg with --enable-libopencv.
674 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
676 @var{filter_name} is the name of the libopencv filter to apply.
678 @var{filter_params} specifies the parameters to pass to the libopencv
679 filter. If not specified the default values are assumed.
681 Refer to the official libopencv documentation for more precise
683 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
685 Follows the list of supported libopencv filters.
690 Dilate an image by using a specific structuring element.
691 This filter corresponds to the libopencv function @code{cvDilate}.
693 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
695 @var{struct_el} represents a structuring element, and has the syntax:
696 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
698 @var{cols} and @var{rows} represent the number of colums and rows of
699 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
700 point, and @var{shape} the shape for the structuring element, and
701 can be one of the values "rect", "cross", "ellipse", "custom".
703 If the value for @var{shape} is "custom", it must be followed by a
704 string of the form "=@var{filename}". The file with name
705 @var{filename} is assumed to represent a binary image, with each
706 printable character corresponding to a bright pixel. When a custom
707 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
708 or columns and rows of the read file are assumed instead.
710 The default value for @var{struct_el} is "3x3+0x0/rect".
712 @var{nb_iterations} specifies the number of times the transform is
713 applied to the image, and defaults to 1.
717 # use the default values
720 # dilate using a structuring element with a 5x5 cross, iterate two times
721 ocv=dilate=5x5+2x2/cross:2
723 # read the shape from the file diamond.shape, iterate two times
724 # the file diamond.shape may contain a pattern of characters like this:
730 # the specified cols and rows are ignored (but not the anchor point coordinates)
731 ocv=0x0+2x2/custom=diamond.shape:2
736 Erode an image by using a specific structuring element.
737 This filter corresponds to the libopencv function @code{cvErode}.
739 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
740 with the same meaning and use of those of the dilate filter
745 Smooth the input video.
747 The filter takes the following parameters:
748 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
750 @var{type} is the type of smooth filter to apply, and can be one of
751 the following values: "blur", "blur_no_scale", "median", "gaussian",
752 "bilateral". The default value is "gaussian".
754 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
755 parameters whose meanings depend on smooth type. @var{param1} and
756 @var{param2} accept integer positive values or 0, @var{param3} and
757 @var{param4} accept float values.
759 The default value for @var{param1} is 3, the default value for the
760 other parameters is 0.
762 These parameters correspond to the parameters assigned to the
763 libopencv function @code{cvSmooth}.
767 Overlay one video on top of another.
769 It takes two inputs and one output, the first input is the "main"
770 video on which the second input is overlayed.
772 It accepts the parameters: @var{x}:@var{y}.
774 @var{x} is the x coordinate of the overlayed video on the main video,
775 @var{y} is the y coordinate. The parameters are expressions containing
776 the following parameters:
780 main input width and height
783 same as @var{main_w} and @var{main_h}
785 @item overlay_w, overlay_h
786 overlay input width and height
789 same as @var{overlay_w} and @var{overlay_h}
792 Be aware that frames are taken from each input video in timestamp
793 order, hence, if their initial timestamps differ, it is a a good idea
794 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
795 have them begin in the same zero timestamp, as it does the example for
796 the @var{movie} filter.
798 Follow some examples:
800 # draw the overlay at 10 pixels from the bottom right
801 # corner of the main video.
802 overlay=main_w-overlay_w-10:main_h-overlay_h-10
804 # insert a transparent PNG logo in the bottom left corner of the input
805 movie=logo.png [logo];
806 [in][logo] overlay=10:main_h-overlay_h-10 [out]
808 # insert 2 different transparent PNG logos (second logo on bottom
810 movie=logo1.png [logo1];
811 movie=logo2.png [logo2];
812 [in][logo1] overlay=10:H-h-10 [in+logo1];
813 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
815 # add a transparent color layer on top of the main video,
816 # WxH specifies the size of the main input to the overlay filter
817 color=red@.3:WxH [over]; [in][over] overlay [out]
820 You can chain togheter more overlays but the efficiency of such
821 approach is yet to be tested.
825 Add paddings to the input image, and places the original input at the
826 given coordinates @var{x}, @var{y}.
828 It accepts the following parameters:
829 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
831 Follows the description of the accepted parameters.
836 Specify the size of the output image with the paddings added. If the
837 value for @var{width} or @var{height} is 0, the corresponding input size
838 is used for the output.
840 The default value of @var{width} and @var{height} is 0.
844 Specify the offsets where to place the input image in the padded area
845 with respect to the top/left border of the output image.
847 The default value of @var{x} and @var{y} is 0.
851 Specify the color of the padded area, it can be the name of a color
852 (case insensitive match) or a 0xRRGGBB[AA] sequence.
854 The default value of @var{color} is "black".
861 # Add paddings with color "violet" to the input video. Output video
862 # size is 640x480, the top-left corner of the input video is placed at
864 pad=640:480:0:40:violet
869 Pixel format descriptor test filter, mainly useful for internal
870 testing. The output video should be equal to the input video.
874 format=monow, pixdesctest
877 can be used to test the monowhite pixel format descriptor definition.
881 Scale the input video to @var{width}:@var{height} and/or convert the image format.
883 For example the command:
886 ./ffmpeg -i in.avi -vf "scale=200:100" out.avi
889 will scale the input video to a size of 200x100.
891 If the input image format is different from the format requested by
892 the next filter, the scale filter will convert the input to the
895 If the value for @var{width} or @var{height} is 0, the respective input
896 size is used for the output.
898 If the value for @var{width} or @var{height} is -1, the scale filter will
899 use, for the respective output size, a value that maintains the aspect
900 ratio of the input image.
902 The default value of @var{width} and @var{height} is 0.
906 Change the PTS (presentation timestamp) of the input video frames.
908 Accept in input an expression evaluated through the eval API, which
909 can contain the following constants:
913 the presentation timestamp in input
925 the count of the input frame, starting from 0.
928 the PTS of the first video frame
931 tell if the current frame is interlaced
934 original position in the file of the frame, or undefined if undefined
935 for the current frame
945 Some examples follow:
948 # start counting PTS from zero
960 # fixed rate 25 fps with some jitter
961 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
966 Set the timebase to use for the output frames timestamps.
967 It is mainly useful for testing timebase configuration.
969 It accepts in input an arithmetic expression representing a rational.
970 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
971 default timebase), and "intb" (the input timebase).
973 The default value for the input is "intb".
975 Follow some examples.
978 # set the timebase to 1/25
981 # set the timebase to 1/10
984 #set the timebase to 1001/1000
987 #set the timebase to 2*intb
990 #set the default timebase value
996 Pass the images of input video on to next video filter as multiple
1000 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1003 The filter accepts the slice height as parameter. If the parameter is
1004 not specified it will use the default value of 16.
1006 Adding this in the beginning of filter chains should make filtering
1007 faster due to better use of the memory cache.
1011 Transpose rows with columns in the input video and optionally flip it.
1013 It accepts a parameter representing an integer, which can assume the
1018 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1026 Rotate by 90 degrees clockwise, that is:
1034 Rotate by 90 degrees counterclockwise, that is:
1042 Rotate by 90 degrees clockwise and vertically flip, that is:
1052 Sharpen or blur the input video.
1054 It accepts the following parameters:
1055 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1057 Negative values for the amount will blur the input video, while positive
1058 values will sharpen. All parameters are optional and default to the
1059 equivalent of the string '5:5:1.0:0:0:0.0'.
1064 Set the luma matrix horizontal size. It can be an integer between 3
1065 and 13, default value is 5.
1068 Set the luma matrix vertical size. It can be an integer between 3
1069 and 13, default value is 5.
1072 Set the luma effect strength. It can be a float number between -2.0
1073 and 5.0, default value is 1.0.
1075 @item chroma_msize_x
1076 Set the chroma matrix horizontal size. It can be an integer between 3
1077 and 13, default value is 0.
1079 @item chroma_msize_y
1080 Set the chroma matrix vertical size. It can be an integer between 3
1081 and 13, default value is 0.
1084 Set the chroma effect strength. It can be a float number between -2.0
1085 and 5.0, default value is 0.0.
1090 # Strong luma sharpen effect parameters
1093 # Strong blur of both luma and chroma parameters
1094 unsharp=7:7:-2:7:7:-2
1096 # Use the default values with @command{ffmpeg}
1097 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1102 Flip the input video vertically.
1105 ./ffmpeg -i in.avi -vf "vflip" out.avi
1110 Deinterlace the input video ("yadif" means "yet another deinterlacing
1113 It accepts the optional parameters: @var{mode}:@var{parity}.
1115 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1120 output 1 frame for each frame
1122 output 1 frame for each field
1124 like 0 but skips spatial interlacing check
1126 like 1 but skips spatial interlacing check
1131 @var{parity} specifies the picture field parity assumed for the input
1132 interlaced video, accepts one of the following values:
1136 assume bottom field first
1138 assume top field first
1140 enable automatic detection
1143 Default value is -1.
1144 If interlacing is unknown or decoder does not export this information,
1145 top field first will be assumed.
1147 @c man end VIDEO FILTERS
1149 @chapter Video Sources
1150 @c man begin VIDEO SOURCES
1152 Below is a description of the currently available video sources.
1156 Buffer video frames, and make them available to the filter chain.
1158 This source is mainly intended for a programmatic use, in particular
1159 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1161 It accepts the following parameters:
1162 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
1164 All the parameters need to be explicitely defined.
1166 Follows the list of the accepted parameters.
1171 Specify the width and height of the buffered video frames.
1173 @item pix_fmt_string
1174 A string representing the pixel format of the buffered video frames.
1175 It may be a number corresponding to a pixel format, or a pixel format
1178 @item timebase_num, timebase_den
1179 Specify numerator and denomitor of the timebase assumed by the
1180 timestamps of the buffered frames.
1182 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1183 Specify numerator and denominator of the sample aspect ratio assumed
1184 by the video frames.
1189 buffer=320:240:yuv410p:1:24:1:1
1192 will instruct the source to accept video frames with size 320x240 and
1193 with format "yuv410p", assuming 1/24 as the timestamps timebase and
1194 square pixels (1:1 sample aspect ratio).
1195 Since the pixel format with name "yuv410p" corresponds to the number 6
1196 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1197 this example corresponds to:
1199 buffer=320:240:6:1:24
1204 Provide an uniformly colored input.
1206 It accepts the following parameters:
1207 @var{color}:@var{frame_size}:@var{frame_rate}
1209 Follows the description of the accepted parameters.
1214 Specify the color of the source. It can be the name of a color (case
1215 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1216 alpha specifier. The default value is "black".
1219 Specify the size of the sourced video, it may be a string of the form
1220 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1221 default value is "320x240".
1224 Specify the frame rate of the sourced video, as the number of frames
1225 generated per second. It has to be a string in the format
1226 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1227 number or a valid video frame rate abbreviation. The default value is
1232 For example the following graph description will generate a red source
1233 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1234 frames per second, which will be overlayed over the source connected
1235 to the pad with identifier "in".
1238 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1243 Read a video stream from a movie container.
1245 It accepts the syntax: @var{movie_name}[:@var{options}] where
1246 @var{movie_name} is the name of the resource to read (not necessarily
1247 a file but also a device or a stream accessed through some protocol),
1248 and @var{options} is an optional sequence of @var{key}=@var{value}
1249 pairs, separated by ":".
1251 The description of the accepted options follows.
1255 @item format_name, f
1256 Specifies the format assumed for the movie to read, and can be either
1257 the name of a container or an input device. If not specified the
1258 format is guessed from @var{movie_name} or by probing.
1260 @item seek_point, sp
1261 Specifies the seek point in seconds, the frames will be output
1262 starting from this seek point, the parameter is evaluated with
1263 @code{av_strtod} so the numerical value may be suffixed by an IS
1264 postfix. Default value is "0".
1266 @item stream_index, si
1267 Specifies the index of the video stream to read. If the value is -1,
1268 the best suited video stream will be automatically selected. Default
1273 This filter allows to overlay a second video on top of main input of
1274 a filtergraph as shown in this graph:
1276 input -----------> deltapts0 --> overlay --> output
1279 movie --> scale--> deltapts1 -------+
1282 Some examples follow:
1284 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1285 # on top of the input labelled as "in".
1286 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1287 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1289 # read from a video4linux2 device, and overlay it on top of the input
1291 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1292 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1298 Null video source, never return images. It is mainly useful as a
1299 template and to be employed in analysis / debugging tools.
1301 It accepts as optional parameter a string of the form
1302 @var{width}:@var{height}:@var{timebase}.
1304 @var{width} and @var{height} specify the size of the configured
1305 source. The default values of @var{width} and @var{height} are
1306 respectively 352 and 288 (corresponding to the CIF size format).
1308 @var{timebase} specifies an arithmetic expression representing a
1309 timebase. The expression can contain the constants "PI", "E", "PHI",
1310 "AVTB" (the default timebase), and defaults to the value "AVTB".
1314 Provide a frei0r source.
1316 To enable compilation of this filter you need to install the frei0r
1317 header and configure FFmpeg with --enable-frei0r.
1319 The source supports the syntax:
1321 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1324 @var{size} is the size of the video to generate, may be a string of the
1325 form @var{width}x@var{height} or a frame size abbreviation.
1326 @var{rate} is the rate of the video to generate, may be a string of
1327 the form @var{num}/@var{den} or a frame rate abbreviation.
1328 @var{src_name} is the name to the frei0r source to load. For more
1329 information regarding frei0r and how to set the parameters read the
1330 section "frei0r" (@pxref{frei0r}) in the description of the video
1333 Some examples follow:
1335 # generate a frei0r partik0l source with size 200x200 and framerate 10
1336 # which is overlayed on the overlay filter main input
1337 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1340 @c man end VIDEO SOURCES
1342 @chapter Video Sinks
1343 @c man begin VIDEO SINKS
1345 Below is a description of the currently available video sinks.
1349 Null video sink, do absolutely nothing with the input video. It is
1350 mainly useful as a template and to be employed in analysis / debugging
1353 @c man end VIDEO SINKS