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 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 Buffer audio frames, and make them available to the end of filter chain.
151 This sink is mainly intended for programmatic use, in particular
152 through the interface defined in @file{libavfilter/asink_abuffer.h}.
154 It requires a pointer to a ABufferSinkContext structure, which defines the
155 incoming buffers' format, to be passed as the opaque parameter to
156 @code{avfilter_init_filter} for initialization.
160 Null audio sink, do absolutely nothing with the input audio. It is
161 mainly useful as a template and to be employed in analysis / debugging
164 @c man end AUDIO SINKS
166 @chapter Video Filters
167 @c man begin VIDEO FILTERS
169 When you configure your FFmpeg build, you can disable any of the
170 existing filters using --disable-filters.
171 The configure output will show the video filters included in your
174 Below is a description of the currently available video filters.
178 Detect frames that are (almost) completely black. Can be useful to
179 detect chapter transitions or commercials. Output lines consist of
180 the frame number of the detected frame, the percentage of blackness,
181 the position in the file if known or -1 and the timestamp in seconds.
183 In order to display the output lines, you need to set the loglevel at
184 least to the AV_LOG_INFO value.
186 The filter accepts the syntax:
188 blackframe[=@var{amount}:[@var{threshold}]]
191 @var{amount} is the percentage of the pixels that have to be below the
192 threshold, and defaults to 98.
194 @var{threshold} is the threshold below which a pixel value is
195 considered black, and defaults to 32.
199 Apply boxblur algorithm to the input video.
201 This filter accepts the parameters:
202 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
204 Chroma and alpha parameters are optional, if not specified they default
205 to the corresponding values set for @var{luma_radius} and
208 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
209 the radius in pixels of the box used for blurring the corresponding
210 input plane. They are expressions, and can contain the following
214 the input width and heigth in pixels
217 the input chroma image width and height in pixels
220 horizontal and vertical chroma subsample values. For example for the
221 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
224 The radius must be a non-negative number, and must be not greater than
225 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
226 and of @code{min(cw,ch)/2} for the chroma planes.
228 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
229 how many times the boxblur filter is applied to the corresponding
232 Some examples follow:
237 Apply a boxblur filter with luma, chroma, and alpha radius
244 Set luma radius to 2, alpha and chroma radius to 0
250 Set luma and chroma radius to a fraction of the video dimension
252 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
259 Copy the input source unchanged to the output. Mainly useful for
264 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
266 The parameters are expressions containing the following constants:
270 the corresponding mathematical approximated values for e
271 (euler number), pi (greek PI), PHI (golden ratio)
274 the computed values for @var{x} and @var{y}. They are evaluated for
278 the input width and heigth
281 same as @var{in_w} and @var{in_h}
284 the output (cropped) width and heigth
287 same as @var{out_w} and @var{out_h}
290 same as @var{iw} / @var{ih}
293 input sample aspect ratio
296 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
299 horizontal and vertical chroma subsample values. For example for the
300 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
303 the number of input frame, starting from 0
306 the position in the file of the input frame, NAN if unknown
309 timestamp expressed in seconds, NAN if the input timestamp is unknown
313 The @var{out_w} and @var{out_h} parameters specify the expressions for
314 the width and height of the output (cropped) video. They are
315 evaluated just at the configuration of the filter.
317 The default value of @var{out_w} is "in_w", and the default value of
318 @var{out_h} is "in_h".
320 The expression for @var{out_w} may depend on the value of @var{out_h},
321 and the expression for @var{out_h} may depend on @var{out_w}, but they
322 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
323 evaluated after @var{out_w} and @var{out_h}.
325 The @var{x} and @var{y} parameters specify the expressions for the
326 position of the top-left corner of the output (non-cropped) area. They
327 are evaluated for each frame. If the evaluated value is not valid, it
328 is approximated to the nearest valid value.
330 The default value of @var{x} is "(in_w-out_w)/2", and the default
331 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
332 the center of the input image.
334 The expression for @var{x} may depend on @var{y}, and the expression
335 for @var{y} may depend on @var{x}.
337 Follow some examples:
339 # crop the central input area with size 100x100
342 # crop the central input area with size 2/3 of the input video
343 "crop=2/3*in_w:2/3*in_h"
345 # crop the input video central square
348 # delimit the rectangle with the top-left corner placed at position
349 # 100:100 and the right-bottom corner corresponding to the right-bottom
350 # corner of the input image.
351 crop=in_w-100:in_h-100:100:100
353 # crop 10 pixels from the left and right borders, and 20 pixels from
354 # the top and bottom borders
355 "crop=in_w-2*10:in_h-2*20"
357 # keep only the bottom right quarter of the input image
358 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
360 # crop height for getting Greek harmony
361 "crop=in_w:1/PHI*in_w"
364 "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)"
366 # erratic camera effect depending on timestamp
367 "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)"
369 # set x depending on the value of y
370 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
375 Auto-detect crop size.
377 Calculate necessary cropping parameters and prints the recommended
378 parameters through the logging system. The detected dimensions
379 correspond to the non-black area of the input video.
381 It accepts the syntax:
383 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
389 Threshold, which can be optionally specified from nothing (0) to
390 everything (255), defaults to 24.
393 Value which the width/height should be divisible by, defaults to
394 16. The offset is automatically adjusted to center the video. Use 2 to
395 get only even dimensions (needed for 4:2:2 video). 16 is best when
396 encoding to most video codecs.
399 Counter that determines after how many frames cropdetect will reset
400 the previously detected largest video area and start over to detect
401 the current optimal crop area. Defaults to 0.
403 This can be useful when channel logos distort the video area. 0
404 indicates never reset and return the largest area encountered during
410 Draw a colored box on the input image.
412 It accepts the syntax:
414 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
420 Specify the top left corner coordinates of the box. Default to 0.
423 Specify the width and height of the box, if 0 they are interpreted as
424 the input width and height. Default to 0.
427 Specify the color of the box to write, it can be the name of a color
428 (case insensitive match) or a 0xRRGGBB[AA] sequence.
431 Follow some examples:
433 # draw a black box around the edge of the input image
436 # draw a box with color red and an opacity of 50%
437 drawbox=10:20:200:60:red@@0.5"
442 Draw text string or text from specified file on top of video using the
445 To enable compilation of this filter you need to configure FFmpeg with
446 @code{--enable-libfreetype}.
448 The filter also recognizes strftime() sequences in the provided text
449 and expands them accordingly. Check the documentation of strftime().
451 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
454 The description of the accepted parameters follows.
459 The font file to be used for drawing text. Path must be included.
460 This parameter is mandatory.
463 The text string to be drawn. The text must be a sequence of UTF-8
465 This parameter is mandatory if no file is specified with the parameter
469 A text file containing text to be drawn. The text must be a sequence
470 of UTF-8 encoded characters.
472 This parameter is mandatory if no text string is specified with the
473 parameter @var{text}.
475 If both text and textfile are specified, an error is thrown.
478 The offsets where text will be drawn within the video frame.
479 Relative to the top/left border of the output image.
481 The default value of @var{x} and @var{y} is 0.
484 The font size to be used for drawing text.
485 The default value of @var{fontsize} is 16.
488 The color to be used for drawing fonts.
489 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
490 (e.g. "0xff000033"), possibly followed by an alpha specifier.
491 The default value of @var{fontcolor} is "black".
494 The color to be used for drawing box around text.
495 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
496 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
497 The default value of @var{boxcolor} is "white".
500 Used to draw a box around text using background color.
501 Value should be either 1 (enable) or 0 (disable).
502 The default value of @var{box} is 0.
504 @item shadowx, shadowy
505 The x and y offsets for the text shadow position with respect to the
506 position of the text. They can be either positive or negative
507 values. Default value for both is "0".
510 The color to be used for drawing a shadow behind the drawn text. It
511 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
512 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
513 The default value of @var{shadowcolor} is "black".
516 Flags to be used for loading the fonts.
518 The flags map the corresponding flags supported by libfreetype, and are
519 a combination of the following values:
526 @item vertical_layout
530 @item ignore_global_advance_width
532 @item ignore_transform
539 Default value is "render".
541 For more information consult the documentation for the FT_LOAD_*
545 The size in number of spaces to use for rendering the tab.
549 For example the command:
551 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
554 will draw "Test Text" with font FreeSerif, using the default values
555 for the optional parameters.
559 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
560 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
563 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
564 and y=50 (counting from the top-left corner of the screen), text is
565 yellow with a red box around it. Both the text and the box have an
568 Note that the double quotes are not necessary if spaces are not used
569 within the parameter list.
571 For more information about libfreetype, check:
572 @url{http://www.freetype.org/}.
576 Apply fade-in/out effect to input video.
578 It accepts the parameters:
579 @var{type}:@var{start_frame}:@var{nb_frames}
581 @var{type} specifies if the effect type, can be either "in" for
582 fade-in, or "out" for a fade-out effect.
584 @var{start_frame} specifies the number of the start frame for starting
585 to apply the fade effect.
587 @var{nb_frames} specifies the number of frames for which the fade
588 effect has to last. At the end of the fade-in effect the output video
589 will have the same intensity as the input video, at the end of the
590 fade-out transition the output video will be completely black.
592 A few usage examples follow, usable too as test scenarios.
594 # fade in first 30 frames of video
597 # fade out last 45 frames of a 200-frame video
600 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
601 fade=in:0:25, fade=out:975:25
603 # make first 5 frames black, then fade in from frame 5-24
609 Transform the field order of the input video.
611 It accepts one parameter which specifies the required field order that
612 the input interlaced video will be transformed to. The parameter can
613 assume one of the following values:
617 output bottom field first
619 output top field first
622 Default value is "tff".
624 Transformation is achieved by shifting the picture content up or down
625 by one line, and filling the remaining line with appropriate picture content.
626 This method is consistent with most broadcast field order converters.
628 If the input video is not flagged as being interlaced, or it is already
629 flagged as being of the required output field order then this filter does
630 not alter the incoming video.
632 This filter is very useful when converting to or from PAL DV material,
633 which is bottom field first.
637 ./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
642 Buffer input images and send them when they are requested.
644 This filter is mainly useful when auto-inserted by the libavfilter
647 The filter does not take parameters.
651 Convert the input video to one of the specified pixel formats.
652 Libavfilter will try to pick one that is supported for the input to
655 The filter accepts a list of pixel format names, separated by ":",
656 for example "yuv420p:monow:rgb24".
658 Some examples follow:
660 # convert the input video to the format "yuv420p"
663 # convert the input video to any of the formats in the list
664 format=yuv420p:yuv444p:yuv410p
670 Apply a frei0r effect to the input video.
672 To enable compilation of this filter you need to install the frei0r
673 header and configure FFmpeg with --enable-frei0r.
675 The filter supports the syntax:
677 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
680 @var{filter_name} is the name to the frei0r effect to load. If the
681 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
682 is searched in each one of the directories specified by the colon
683 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
684 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
685 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
687 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
688 for the frei0r effect.
690 A frei0r effect parameter can be a boolean (whose values are specified
691 with "y" and "n"), a double, a color (specified by the syntax
692 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
693 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
694 description), a position (specified by the syntax @var{X}/@var{Y},
695 @var{X} and @var{Y} being float numbers) and a string.
697 The number and kind of parameters depend on the loaded effect. If an
698 effect parameter is not specified the default value is set.
700 Some examples follow:
702 # apply the distort0r effect, set the first two double parameters
703 frei0r=distort0r:0.5:0.01
705 # apply the colordistance effect, takes a color as first parameter
706 frei0r=colordistance:0.2/0.3/0.4
707 frei0r=colordistance:violet
708 frei0r=colordistance:0x112233
710 # apply the perspective effect, specify the top left and top right
712 frei0r=perspective:0.2/0.2:0.8/0.2
715 For more information see:
716 @url{http://piksel.org/frei0r}
720 Fix the banding artifacts that are sometimes introduced into nearly flat
721 regions by truncation to 8bit colordepth.
722 Interpolate the gradients that should go where the bands are, and
725 This filter is designed for playback only. Do not use it prior to
726 lossy compression, because compression tends to lose the dither and
727 bring back the bands.
729 The filter takes two optional parameters, separated by ':':
730 @var{strength}:@var{radius}
732 @var{strength} is the maximum amount by which the filter will change
733 any one pixel. Also the threshold for detecting nearly flat
734 regions. Acceptable values range from .51 to 255, default value is
735 1.2, out-of-range values will be clipped to the valid range.
737 @var{radius} is the neighborhood to fit the gradient to. A larger
738 radius makes for smoother gradients, but also prevents the filter from
739 modifying the pixels near detailed regions. Acceptable values are
740 8-32, default value is 16, out-of-range values will be clipped to the
753 Flip the input video horizontally.
755 For example to horizontally flip the video in input with
758 ffmpeg -i in.avi -vf "hflip" out.avi
763 High precision/quality 3d denoise filter. This filter aims to reduce
764 image noise producing smooth images and making still images really
765 still. It should enhance compressibility.
767 It accepts the following optional parameters:
768 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
772 a non-negative float number which specifies spatial luma strength,
776 a non-negative float number which specifies spatial chroma strength,
777 defaults to 3.0*@var{luma_spatial}/4.0
780 a float number which specifies luma temporal strength, defaults to
781 6.0*@var{luma_spatial}/4.0
784 a float number which specifies chroma temporal strength, defaults to
785 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
788 @section lut, lutrgb, lutyuv
790 Compute a look-up table for binding each pixel component input value
791 to an output value, and apply it to input video.
793 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
794 to an RGB input video.
796 These filters accept in input a ":"-separated list of options, which
797 specify the expressions used for computing the lookup table for the
798 corresponding pixel component values.
800 The @var{lut} filter requires either YUV or RGB pixel formats in
801 input, and accepts the options:
803 @var{c0} (first pixel component)
804 @var{c1} (second pixel component)
805 @var{c2} (third pixel component)
806 @var{c3} (fourth pixel component, corresponds to the alpha component)
809 The exact component associated to each option depends on the format in
812 The @var{lutrgb} filter requires RGB pixel formats in input, and
815 @var{r} (red component)
816 @var{g} (green component)
817 @var{b} (blue component)
818 @var{a} (alpha component)
821 The @var{lutyuv} filter requires YUV pixel formats in input, and
824 @var{y} (Y/luminance component)
825 @var{u} (U/Cb component)
826 @var{v} (V/Cr component)
827 @var{a} (alpha component)
830 The expressions can contain the following constants and functions:
834 the corresponding mathematical approximated values for e
835 (euler number), pi (greek PI), PHI (golden ratio)
838 the input width and heigth
841 input value for the pixel component
844 the input value clipped in the @var{minval}-@var{maxval} range
847 maximum value for the pixel component
850 minimum value for the pixel component
853 the negated value for the pixel component value clipped in the
854 @var{minval}-@var{maxval} range , it corresponds to the expression
855 "maxval-clipval+minval"
858 the computed value in @var{val} clipped in the
859 @var{minval}-@var{maxval} range
861 @item gammaval(gamma)
862 the computed gamma correction value of the pixel component value
863 clipped in the @var{minval}-@var{maxval} range, corresponds to the
865 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
869 All expressions default to "val".
871 Some examples follow:
874 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
875 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
877 # the above is the same as
878 lutrgb="r=negval:g=negval:b=negval"
879 lutyuv="y=negval:u=negval:v=negval"
884 # remove chroma components, turns the video into a graytone image
887 # apply a luma burning effect
890 # remove green and blue components
893 # set a constant alpha channel value on input
894 format=rgba,lutrgb=a="maxval-minval/2"
896 # correct luminance gamma by a 0.5 factor
897 lutyuv=y=gammaval(0.5)
902 Apply an MPlayer filter to the input video.
904 This filter provides a wrapper around most of the filters of
907 This wrapper is considered experimental. Some of the wrapped filters
908 may not work properly and we may drop support for them, as they will
909 be implemented natively into FFmpeg. Thus you should avoid
910 depending on them when writing portable scripts.
912 The filters accepts the parameters:
913 @var{filter_name}[:=]@var{filter_params}
915 @var{filter_name} is the name of a supported MPlayer filter,
916 @var{filter_params} is a string containing the parameters accepted by
919 The list of the currently supported filters follows:
975 The parameter syntax and behavior for the listed filters are the same
976 of the corresponding MPlayer filters. For detailed instructions check
977 the "VIDEO FILTERS" section in the MPlayer manual.
979 Some examples follow:
981 # remove a logo by interpolating the surrounding pixels
982 mp=delogo=200:200:80:20:1
984 # adjust gamma, brightness, contrast
987 # tweak hue and saturation
991 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
997 This filter accepts an integer in input, if non-zero it negates the
998 alpha component (if available). The default value in input is 0.
1002 Force libavfilter not to use any of the specified pixel formats for the
1003 input to the next filter.
1005 The filter accepts a list of pixel format names, separated by ":",
1006 for example "yuv420p:monow:rgb24".
1008 Some examples follow:
1010 # force libavfilter to use a format different from "yuv420p" for the
1011 # input to the vflip filter
1012 noformat=yuv420p,vflip
1014 # convert the input video to any of the formats not contained in the list
1015 noformat=yuv420p:yuv444p:yuv410p
1020 Pass the video source unchanged to the output.
1024 Apply video transform using libopencv.
1026 To enable this filter install libopencv library and headers and
1027 configure FFmpeg with --enable-libopencv.
1029 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1031 @var{filter_name} is the name of the libopencv filter to apply.
1033 @var{filter_params} specifies the parameters to pass to the libopencv
1034 filter. If not specified the default values are assumed.
1036 Refer to the official libopencv documentation for more precise
1038 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1040 Follows the list of supported libopencv filters.
1045 Dilate an image by using a specific structuring element.
1046 This filter corresponds to the libopencv function @code{cvDilate}.
1048 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1050 @var{struct_el} represents a structuring element, and has the syntax:
1051 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1053 @var{cols} and @var{rows} represent the number of colums and rows of
1054 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1055 point, and @var{shape} the shape for the structuring element, and
1056 can be one of the values "rect", "cross", "ellipse", "custom".
1058 If the value for @var{shape} is "custom", it must be followed by a
1059 string of the form "=@var{filename}". The file with name
1060 @var{filename} is assumed to represent a binary image, with each
1061 printable character corresponding to a bright pixel. When a custom
1062 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1063 or columns and rows of the read file are assumed instead.
1065 The default value for @var{struct_el} is "3x3+0x0/rect".
1067 @var{nb_iterations} specifies the number of times the transform is
1068 applied to the image, and defaults to 1.
1070 Follow some example:
1072 # use the default values
1075 # dilate using a structuring element with a 5x5 cross, iterate two times
1076 ocv=dilate=5x5+2x2/cross:2
1078 # read the shape from the file diamond.shape, iterate two times
1079 # the file diamond.shape may contain a pattern of characters like this:
1085 # the specified cols and rows are ignored (but not the anchor point coordinates)
1086 ocv=0x0+2x2/custom=diamond.shape:2
1091 Erode an image by using a specific structuring element.
1092 This filter corresponds to the libopencv function @code{cvErode}.
1094 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1095 with the same syntax and semantics as the @ref{dilate} filter.
1099 Smooth the input video.
1101 The filter takes the following parameters:
1102 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1104 @var{type} is the type of smooth filter to apply, and can be one of
1105 the following values: "blur", "blur_no_scale", "median", "gaussian",
1106 "bilateral". The default value is "gaussian".
1108 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1109 parameters whose meanings depend on smooth type. @var{param1} and
1110 @var{param2} accept integer positive values or 0, @var{param3} and
1111 @var{param4} accept float values.
1113 The default value for @var{param1} is 3, the default value for the
1114 other parameters is 0.
1116 These parameters correspond to the parameters assigned to the
1117 libopencv function @code{cvSmooth}.
1121 Overlay one video on top of another.
1123 It takes two inputs and one output, the first input is the "main"
1124 video on which the second input is overlayed.
1126 It accepts the parameters: @var{x}:@var{y}.
1128 @var{x} is the x coordinate of the overlayed video on the main video,
1129 @var{y} is the y coordinate. The parameters are expressions containing
1130 the following parameters:
1133 @item main_w, main_h
1134 main input width and height
1137 same as @var{main_w} and @var{main_h}
1139 @item overlay_w, overlay_h
1140 overlay input width and height
1143 same as @var{overlay_w} and @var{overlay_h}
1146 Be aware that frames are taken from each input video in timestamp
1147 order, hence, if their initial timestamps differ, it is a a good idea
1148 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1149 have them begin in the same zero timestamp, as it does the example for
1150 the @var{movie} filter.
1152 Follow some examples:
1154 # draw the overlay at 10 pixels from the bottom right
1155 # corner of the main video.
1156 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1158 # insert a transparent PNG logo in the bottom left corner of the input
1159 movie=logo.png [logo];
1160 [in][logo] overlay=10:main_h-overlay_h-10 [out]
1162 # insert 2 different transparent PNG logos (second logo on bottom
1164 movie=logo1.png [logo1];
1165 movie=logo2.png [logo2];
1166 [in][logo1] overlay=10:H-h-10 [in+logo1];
1167 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
1169 # add a transparent color layer on top of the main video,
1170 # WxH specifies the size of the main input to the overlay filter
1171 color=red@.3:WxH [over]; [in][over] overlay [out]
1174 You can chain togheter more overlays but the efficiency of such
1175 approach is yet to be tested.
1179 Add paddings to the input image, and places the original input at the
1180 given coordinates @var{x}, @var{y}.
1182 It accepts the following parameters:
1183 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1185 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1186 expressions containing the following constants:
1190 the corresponding mathematical approximated values for e
1191 (euler number), pi (greek PI), phi (golden ratio)
1194 the input video width and heigth
1197 same as @var{in_w} and @var{in_h}
1200 the output width and heigth, that is the size of the padded area as
1201 specified by the @var{width} and @var{height} expressions
1204 same as @var{out_w} and @var{out_h}
1207 x and y offsets as specified by the @var{x} and @var{y}
1208 expressions, or NAN if not yet specified
1211 same as @var{iw} / @var{ih}
1214 input sample aspect ratio
1217 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1220 horizontal and vertical chroma subsample values. For example for the
1221 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1224 Follows the description of the accepted parameters.
1229 Specify the size of the output image with the paddings added. If the
1230 value for @var{width} or @var{height} is 0, the corresponding input size
1231 is used for the output.
1233 The @var{width} expression can reference the value set by the
1234 @var{height} expression, and viceversa.
1236 The default value of @var{width} and @var{height} is 0.
1240 Specify the offsets where to place the input image in the padded area
1241 with respect to the top/left border of the output image.
1243 The @var{x} expression can reference the value set by the @var{y}
1244 expression, and viceversa.
1246 The default value of @var{x} and @var{y} is 0.
1250 Specify the color of the padded area, it can be the name of a color
1251 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1253 The default value of @var{color} is "black".
1257 Some examples follow:
1260 # Add paddings with color "violet" to the input video. Output video
1261 # size is 640x480, the top-left corner of the input video is placed at
1263 pad=640:480:0:40:violet
1265 # pad the input to get an output with dimensions increased bt 3/2,
1266 # and put the input video at the center of the padded area
1267 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1269 # pad the input to get a squared output with size equal to the maximum
1270 # value between the input width and height, and put the input video at
1271 # the center of the padded area
1272 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1274 # pad the input to get a final w/h ratio of 16:9
1275 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1277 # for anamorphic video, in order to set the output display aspect ratio,
1278 # it is necessary to use sar in the expression, according to the relation:
1279 # (ih * X / ih) * sar = output_dar
1280 # X = output_dar / sar
1281 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
1283 # double output size and put the input video in the bottom-right
1284 # corner of the output padded area
1285 pad="2*iw:2*ih:ow-iw:oh-ih"
1288 @section pixdesctest
1290 Pixel format descriptor test filter, mainly useful for internal
1291 testing. The output video should be equal to the input video.
1295 format=monow, pixdesctest
1298 can be used to test the monowhite pixel format descriptor definition.
1302 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1304 The parameters @var{width} and @var{height} are expressions containing
1305 the following constants:
1309 the corresponding mathematical approximated values for e
1310 (euler number), pi (greek PI), phi (golden ratio)
1313 the input width and heigth
1316 same as @var{in_w} and @var{in_h}
1319 the output (cropped) width and heigth
1322 same as @var{out_w} and @var{out_h}
1325 same as @var{iw} / @var{ih}
1328 input sample aspect ratio
1331 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1334 horizontal and vertical chroma subsample values. For example for the
1335 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1338 If the input image format is different from the format requested by
1339 the next filter, the scale filter will convert the input to the
1342 If the value for @var{width} or @var{height} is 0, the respective input
1343 size is used for the output.
1345 If the value for @var{width} or @var{height} is -1, the scale filter will
1346 use, for the respective output size, a value that maintains the aspect
1347 ratio of the input image.
1349 The default value of @var{width} and @var{height} is 0.
1351 Some examples follow:
1353 # scale the input video to a size of 200x100.
1356 # scale the input to 2x
1358 # the above is the same as
1361 # scale the input to half size
1364 # increase the width, and set the height to the same size
1367 # seek for Greek harmony
1371 # increase the height, and set the width to 3/2 of the height
1374 # increase the size, but make the size a multiple of the chroma
1375 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1377 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1378 scale='min(500\, iw*3/2):-1'
1382 Select frames to pass in output.
1384 It accepts in input an expression, which is evaluated for each input
1385 frame. If the expression is evaluated to a non-zero value, the frame
1386 is selected and passed to the output, otherwise it is discarded.
1388 The expression can contain the following constants:
1401 the sequential number of the filtered frame, starting from 0
1404 the sequential number of the selected frame, starting from 0
1406 @item prev_selected_n
1407 the sequential number of the last selected frame, NAN if undefined
1410 timebase of the input timestamps
1413 the PTS (Presentation TimeStamp) of the filtered video frame,
1414 expressed in @var{TB} units, NAN if undefined
1417 the PTS (Presentation TimeStamp) of the filtered video frame,
1418 expressed in seconds, NAN if undefined
1421 the PTS of the previously filtered video frame, NAN if undefined
1423 @item prev_selected_pts
1424 the PTS of the last previously filtered video frame, NAN if undefined
1426 @item prev_selected_t
1427 the PTS of the last previously selected video frame, NAN if undefined
1430 the PTS of the first video frame in the video, NAN if undefined
1433 the time of the first video frame in the video, NAN if undefined
1436 the picture type of the filtered frame, can assume one of the following
1448 @item interlace_type
1449 the frame interlace type, can assume one of the following values:
1451 @item INTERLACE_TYPE_P
1452 the frame is progressive (not interlaced)
1453 @item INTERLACE_TYPE_T
1454 the frame is top-field-first
1455 @item INTERLACE_TYPE_B
1456 the frame is bottom-field-first
1460 1 if the filtered frame is a key-frame, 0 otherwise
1463 the position in the file of the filtered frame, -1 if the information
1464 is not available (e.g. for synthetic video)
1467 The default value of the select expression is "1".
1469 Some examples follow:
1472 # select all frames in input
1475 # the above is the same as:
1481 # select only I-frames
1482 select='eq(pict_type\,PICT_TYPE_I)'
1484 # select one frame every 100
1485 select='not(mod(n\,100))'
1487 # select only frames contained in the 10-20 time interval
1488 select='gte(t\,10)*lte(t\,20)'
1490 # select only I frames contained in the 10-20 time interval
1491 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,PICT_TYPE_I)'
1493 # select frames with a minimum distance of 10 seconds
1494 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1500 Set the Display Aspect Ratio for the filter output video.
1502 This is done by changing the specified Sample (aka Pixel) Aspect
1503 Ratio, according to the following equation:
1504 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1506 Keep in mind that this filter does not modify the pixel dimensions of
1507 the video frame. Also the display aspect ratio set by this filter may
1508 be changed by later filters in the filterchain, e.g. in case of
1509 scaling or if another "setdar" or a "setsar" filter is applied.
1511 The filter accepts a parameter string which represents the wanted
1512 display aspect ratio.
1513 The parameter can be a floating point number string, or an expression
1514 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1515 numerator and denominator of the aspect ratio.
1516 If the parameter is not specified, it is assumed the value "0:1".
1518 For example to change the display aspect ratio to 16:9, specify:
1521 # the above is equivalent to
1525 See also the @ref{setsar} filter documentation.
1529 Change the PTS (presentation timestamp) of the input video frames.
1531 Accept in input an expression evaluated through the eval API, which
1532 can contain the following constants:
1536 the presentation timestamp in input
1548 the count of the input frame, starting from 0.
1551 the PTS of the first video frame
1554 tell if the current frame is interlaced
1557 original position in the file of the frame, or undefined if undefined
1558 for the current frame
1568 Some examples follow:
1571 # start counting PTS from zero
1583 # fixed rate 25 fps with some jitter
1584 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1590 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1592 Note that as a consequence of the application of this filter, the
1593 output display aspect ratio will change according to the following
1595 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1597 Keep in mind that the sample aspect ratio set by this filter may be
1598 changed by later filters in the filterchain, e.g. if another "setsar"
1599 or a "setdar" filter is applied.
1601 The filter accepts a parameter string which represents the wanted
1602 sample aspect ratio.
1603 The parameter can be a floating point number string, or an expression
1604 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1605 numerator and denominator of the aspect ratio.
1606 If the parameter is not specified, it is assumed the value "0:1".
1608 For example to change the sample aspect ratio to 10:11, specify:
1615 Set the timebase to use for the output frames timestamps.
1616 It is mainly useful for testing timebase configuration.
1618 It accepts in input an arithmetic expression representing a rational.
1619 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1620 default timebase), and "intb" (the input timebase).
1622 The default value for the input is "intb".
1624 Follow some examples.
1627 # set the timebase to 1/25
1630 # set the timebase to 1/10
1633 #set the timebase to 1001/1000
1636 #set the timebase to 2*intb
1639 #set the default timebase value
1645 Show a line containing various information for each input video frame.
1646 The input video is not modified.
1648 The shown line contains a sequence of key/value pairs of the form
1649 @var{key}:@var{value}.
1651 A description of each shown parameter follows:
1655 sequential number of the input frame, starting from 0
1658 Presentation TimeStamp of the input frame, expressed as a number of
1659 time base units. The time base unit depends on the filter input pad.
1662 Presentation TimeStamp of the input frame, expressed as a number of
1666 position of the frame in the input stream, -1 if this information in
1667 unavailable and/or meanigless (for example in case of synthetic video)
1673 sample aspect ratio of the input frame, expressed in the form
1677 size of the input frame, expressed in the form
1678 @var{width}x@var{height}
1681 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1682 for bottom field first)
1685 1 if the frame is a key frame, 0 otherwise
1688 picture type of the input frame ("I" for an I-frame, "P" for a
1689 P-frame, "B" for a B-frame, "?" for unknown type).
1690 Check also the documentation of the @code{AVPictureType} enum and of
1691 the @code{av_get_picture_type_char} function defined in
1692 @file{libavutil/avutil.h}.
1695 Adler-32 checksum of all the planes of the input frame
1697 @item plane_checksum
1698 Adler-32 checksum of each plane of the input frame, expressed in the form
1699 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
1704 Pass the images of input video on to next video filter as multiple
1708 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1711 The filter accepts the slice height as parameter. If the parameter is
1712 not specified it will use the default value of 16.
1714 Adding this in the beginning of filter chains should make filtering
1715 faster due to better use of the memory cache.
1719 Pass on the input video to two outputs. Both outputs are identical to
1724 [in] split [splitout1][splitout2];
1725 [splitout1] crop=100:100:0:0 [cropout];
1726 [splitout2] pad=200:200:100:100 [padout];
1729 will create two separate outputs from the same input, one cropped and
1734 Transpose rows with columns in the input video and optionally flip it.
1736 It accepts a parameter representing an integer, which can assume the
1741 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1749 Rotate by 90 degrees clockwise, that is:
1757 Rotate by 90 degrees counterclockwise, that is:
1765 Rotate by 90 degrees clockwise and vertically flip, that is:
1775 Sharpen or blur the input video.
1777 It accepts the following parameters:
1778 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1780 Negative values for the amount will blur the input video, while positive
1781 values will sharpen. All parameters are optional and default to the
1782 equivalent of the string '5:5:1.0:0:0:0.0'.
1787 Set the luma matrix horizontal size. It can be an integer between 3
1788 and 13, default value is 5.
1791 Set the luma matrix vertical size. It can be an integer between 3
1792 and 13, default value is 5.
1795 Set the luma effect strength. It can be a float number between -2.0
1796 and 5.0, default value is 1.0.
1798 @item chroma_msize_x
1799 Set the chroma matrix horizontal size. It can be an integer between 3
1800 and 13, default value is 0.
1802 @item chroma_msize_y
1803 Set the chroma matrix vertical size. It can be an integer between 3
1804 and 13, default value is 0.
1807 Set the chroma effect strength. It can be a float number between -2.0
1808 and 5.0, default value is 0.0.
1813 # Strong luma sharpen effect parameters
1816 # Strong blur of both luma and chroma parameters
1817 unsharp=7:7:-2:7:7:-2
1819 # Use the default values with @command{ffmpeg}
1820 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1825 Flip the input video vertically.
1828 ./ffmpeg -i in.avi -vf "vflip" out.avi
1833 Deinterlace the input video ("yadif" means "yet another deinterlacing
1836 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
1838 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1843 output 1 frame for each frame
1845 output 1 frame for each field
1847 like 0 but skips spatial interlacing check
1849 like 1 but skips spatial interlacing check
1854 @var{parity} specifies the picture field parity assumed for the input
1855 interlaced video, accepts one of the following values:
1859 assume top field first
1861 assume bottom field first
1863 enable automatic detection
1866 Default value is -1.
1867 If interlacing is unknown or decoder does not export this information,
1868 top field first will be assumed.
1870 @var{auto} specifies if deinterlacer should trust the interlaced flag
1871 and only deinterlace frames marked as interlaced
1875 deinterlace all frames
1877 only deinterlace frames marked as interlaced
1882 @c man end VIDEO FILTERS
1884 @chapter Video Sources
1885 @c man begin VIDEO SOURCES
1887 Below is a description of the currently available video sources.
1891 Buffer video frames, and make them available to the filter chain.
1893 This source is mainly intended for a programmatic use, in particular
1894 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1896 It accepts the following parameters:
1897 @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}
1899 All the parameters but @var{scale_params} need to be explicitely
1902 Follows the list of the accepted parameters.
1907 Specify the width and height of the buffered video frames.
1909 @item pix_fmt_string
1910 A string representing the pixel format of the buffered video frames.
1911 It may be a number corresponding to a pixel format, or a pixel format
1914 @item timebase_num, timebase_den
1915 Specify numerator and denomitor of the timebase assumed by the
1916 timestamps of the buffered frames.
1918 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1919 Specify numerator and denominator of the sample aspect ratio assumed
1920 by the video frames.
1923 Specify the optional parameters to be used for the scale filter which
1924 is automatically inserted when an input change is detected in the
1925 input size or format.
1930 buffer=320:240:yuv410p:1:24:1:1
1933 will instruct the source to accept video frames with size 320x240 and
1934 with format "yuv410p", assuming 1/24 as the timestamps timebase and
1935 square pixels (1:1 sample aspect ratio).
1936 Since the pixel format with name "yuv410p" corresponds to the number 6
1937 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1938 this example corresponds to:
1940 buffer=320:240:6:1:24:1:1
1945 Provide an uniformly colored input.
1947 It accepts the following parameters:
1948 @var{color}:@var{frame_size}:@var{frame_rate}
1950 Follows the description of the accepted parameters.
1955 Specify the color of the source. It can be the name of a color (case
1956 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1957 alpha specifier. The default value is "black".
1960 Specify the size of the sourced video, it may be a string of the form
1961 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1962 default value is "320x240".
1965 Specify the frame rate of the sourced video, as the number of frames
1966 generated per second. It has to be a string in the format
1967 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1968 number or a valid video frame rate abbreviation. The default value is
1973 For example the following graph description will generate a red source
1974 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1975 frames per second, which will be overlayed over the source connected
1976 to the pad with identifier "in".
1979 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1984 Read a video stream from a movie container.
1986 It accepts the syntax: @var{movie_name}[:@var{options}] where
1987 @var{movie_name} is the name of the resource to read (not necessarily
1988 a file but also a device or a stream accessed through some protocol),
1989 and @var{options} is an optional sequence of @var{key}=@var{value}
1990 pairs, separated by ":".
1992 The description of the accepted options follows.
1996 @item format_name, f
1997 Specifies the format assumed for the movie to read, and can be either
1998 the name of a container or an input device. If not specified the
1999 format is guessed from @var{movie_name} or by probing.
2001 @item seek_point, sp
2002 Specifies the seek point in seconds, the frames will be output
2003 starting from this seek point, the parameter is evaluated with
2004 @code{av_strtod} so the numerical value may be suffixed by an IS
2005 postfix. Default value is "0".
2007 @item stream_index, si
2008 Specifies the index of the video stream to read. If the value is -1,
2009 the best suited video stream will be automatically selected. Default
2014 This filter allows to overlay a second video on top of main input of
2015 a filtergraph as shown in this graph:
2017 input -----------> deltapts0 --> overlay --> output
2020 movie --> scale--> deltapts1 -------+
2023 Some examples follow:
2025 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2026 # on top of the input labelled as "in".
2027 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2028 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2030 # read from a video4linux2 device, and overlay it on top of the input
2032 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2033 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2039 Null video source, never return images. It is mainly useful as a
2040 template and to be employed in analysis / debugging tools.
2042 It accepts as optional parameter a string of the form
2043 @var{width}:@var{height}:@var{timebase}.
2045 @var{width} and @var{height} specify the size of the configured
2046 source. The default values of @var{width} and @var{height} are
2047 respectively 352 and 288 (corresponding to the CIF size format).
2049 @var{timebase} specifies an arithmetic expression representing a
2050 timebase. The expression can contain the constants "PI", "E", "PHI",
2051 "AVTB" (the default timebase), and defaults to the value "AVTB".
2055 Provide a frei0r source.
2057 To enable compilation of this filter you need to install the frei0r
2058 header and configure FFmpeg with --enable-frei0r.
2060 The source supports the syntax:
2062 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2065 @var{size} is the size of the video to generate, may be a string of the
2066 form @var{width}x@var{height} or a frame size abbreviation.
2067 @var{rate} is the rate of the video to generate, may be a string of
2068 the form @var{num}/@var{den} or a frame rate abbreviation.
2069 @var{src_name} is the name to the frei0r source to load. For more
2070 information regarding frei0r and how to set the parameters read the
2071 section @ref{frei0r} in the description of the video filters.
2073 Some examples follow:
2075 # generate a frei0r partik0l source with size 200x200 and framerate 10
2076 # which is overlayed on the overlay filter main input
2077 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2080 @section rgbtestsrc, testsrc
2082 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2083 detecting RGB vs BGR issues. You should see a red, green and blue
2084 stripe from top to bottom.
2086 The @code{testsrc} source generates a test video pattern, showing a
2087 color pattern, a scrolling gradient and a timestamp. This is mainly
2088 intended for testing purposes.
2090 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2091 separated by ":". The description of the accepted options follows.
2096 Specify the size of the sourced video, it may be a string of the form
2097 @var{width}x@var{heigth}, or the name of a size abbreviation. The
2098 default value is "320x240".
2101 Specify the frame rate of the sourced video, as the number of frames
2102 generated per second. It has to be a string in the format
2103 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2104 number or a valid video frame rate abbreviation. The default value is
2108 Set the video duration of the sourced video. The accepted syntax is:
2110 [-]HH[:MM[:SS[.m...]]]
2113 See also the function @code{av_parse_time()}.
2115 If not specified, or the expressed duration is negative, the video is
2116 supposed to be generated forever.
2119 For example the following:
2121 testsrc=duration=5.3:size=qcif:rate=10
2124 will generate a video with a duration of 5.3 seconds, with size
2125 176x144 and a framerate of 10 frames per second.
2127 @c man end VIDEO SOURCES
2129 @chapter Video Sinks
2130 @c man begin VIDEO SINKS
2132 Below is a description of the currently available video sinks.
2136 Buffer video frames, and make them available to the end of the filter
2139 This sink is mainly intended for a programmatic use, in particular
2140 through the interface defined in @file{libavfilter/vsink_buffer.h}.
2142 It does not require a string parameter in input, but you need to
2143 specify a pointer to a list of supported pixel formats terminated by
2144 -1 in the opaque parameter provided to @code{avfilter_init_filter}
2145 when initializing this sink.
2149 Null video sink, do absolutely nothing with the input video. It is
2150 mainly useful as a template and to be employed in analysis / debugging
2153 @c man end VIDEO SINKS