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 Libav 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 Libav build, you can disable any of the
159 existing filters using --disable-filters.
160 The configure output will show the video filters included in your
163 Below is a description of the currently available video filters.
167 Detect frames that are (almost) completely black. Can be useful to
168 detect chapter transitions or commercials. Output lines consist of
169 the frame number of the detected frame, the percentage of blackness,
170 the position in the file if known or -1 and the timestamp in seconds.
172 In order to display the output lines, you need to set the loglevel at
173 least to the AV_LOG_INFO value.
175 The filter accepts the syntax:
177 blackframe[=@var{amount}:[@var{threshold}]]
180 @var{amount} is the percentage of the pixels that have to be below the
181 threshold, and defaults to 98.
183 @var{threshold} is the threshold below which a pixel value is
184 considered black, and defaults to 32.
188 Apply boxblur algorithm to the input video.
190 This filter accepts the parameters:
191 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
193 Chroma and alpha parameters are optional, if not specified they default
194 to the corresponding values set for @var{luma_radius} and
197 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
198 the radius in pixels of the box used for blurring the corresponding
199 input plane. They are expressions, and can contain the following
203 the input width and heigth in pixels
206 the input chroma image width and height in pixels
209 horizontal and vertical chroma subsample values. For example for the
210 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
213 The radius must be a non-negative number, and must not be greater than
214 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
215 and of @code{min(cw,ch)/2} for the chroma planes.
217 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
218 how many times the boxblur filter is applied to the corresponding
221 Some examples follow:
226 Apply a boxblur filter with luma, chroma, and alpha radius
233 Set luma radius to 2, alpha and chroma radius to 0
239 Set luma and chroma radius to a fraction of the video dimension
241 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
248 Copy the input source unchanged to the output. Mainly useful for
253 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
255 The parameters are expressions containing the following constants:
259 the corresponding mathematical approximated values for e
260 (euler number), pi (greek PI), PHI (golden ratio)
263 the computed values for @var{x} and @var{y}. They are evaluated for
267 the input width and height
270 same as @var{in_w} and @var{in_h}
273 the output (cropped) width and height
276 same as @var{out_w} and @var{out_h}
279 the number of input frame, starting from 0
282 the position in the file of the input frame, NAN if unknown
285 timestamp expressed in seconds, NAN if the input timestamp is unknown
289 The @var{out_w} and @var{out_h} parameters specify the expressions for
290 the width and height of the output (cropped) video. They are
291 evaluated just at the configuration of the filter.
293 The default value of @var{out_w} is "in_w", and the default value of
294 @var{out_h} is "in_h".
296 The expression for @var{out_w} may depend on the value of @var{out_h},
297 and the expression for @var{out_h} may depend on @var{out_w}, but they
298 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
299 evaluated after @var{out_w} and @var{out_h}.
301 The @var{x} and @var{y} parameters specify the expressions for the
302 position of the top-left corner of the output (non-cropped) area. They
303 are evaluated for each frame. If the evaluated value is not valid, it
304 is approximated to the nearest valid value.
306 The default value of @var{x} is "(in_w-out_w)/2", and the default
307 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
308 the center of the input image.
310 The expression for @var{x} may depend on @var{y}, and the expression
311 for @var{y} may depend on @var{x}.
313 Follow some examples:
315 # crop the central input area with size 100x100
318 # crop the central input area with size 2/3 of the input video
319 "crop=2/3*in_w:2/3*in_h"
321 # crop the input video central square
324 # delimit the rectangle with the top-left corner placed at position
325 # 100:100 and the right-bottom corner corresponding to the right-bottom
326 # corner of the input image.
327 crop=in_w-100:in_h-100:100:100
329 # crop 10 pixels from the left and right borders, and 20 pixels from
330 # the top and bottom borders
331 "crop=in_w-2*10:in_h-2*20"
333 # keep only the bottom right quarter of the input image
334 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
336 # crop height for getting Greek harmony
337 "crop=in_w:1/PHI*in_w"
340 "crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
342 # erratic camera effect depending on timestamp
343 "crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
345 # set x depending on the value of y
346 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
351 Auto-detect crop size.
353 Calculate necessary cropping parameters and prints the recommended
354 parameters through the logging system. The detected dimensions
355 correspond to the non-black area of the input video.
357 It accepts the syntax:
359 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
365 Threshold, which can be optionally specified from nothing (0) to
366 everything (255), defaults to 24.
369 Value which the width/height should be divisible by, defaults to
370 16. The offset is automatically adjusted to center the video. Use 2 to
371 get only even dimensions (needed for 4:2:2 video). 16 is best when
372 encoding to most video codecs.
375 Counter that determines after how many frames cropdetect will reset
376 the previously detected largest video area and start over to detect
377 the current optimal crop area. Defaults to 0.
379 This can be useful when channel logos distort the video area. 0
380 indicates never reset and return the largest area encountered during
386 Suppress a TV station logo by a simple interpolation of the surrounding
387 pixels. Just set a rectangle covering the logo and watch it disappear
388 (and sometimes something even uglier appear - your mileage may vary).
390 The filter accepts parameters as a string of the form
391 "@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
392 @var{key}=@var{value} pairs, separated by ":".
394 The description of the accepted parameters follows.
399 Specify the top left corner coordinates of the logo. They must be
403 Specify the width and height of the logo to clear. They must be
407 Specify the thickness of the fuzzy edge of the rectangle (added to
408 @var{w} and @var{h}). The default value is 4.
411 When set to 1, a green rectangle is drawn on the screen to simplify
412 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
413 @var{band} is set to 4. The default value is 0.
417 Some examples follow.
422 Set a rectangle covering the area with top left corner coordinates 0,0
423 and size 100x77, setting a band of size 10:
429 As the previous example, but use named options:
431 delogo=x=0:y=0:w=100:h=77:band=10
438 Draw a colored box on the input image.
440 It accepts the syntax:
442 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
448 Specify the top left corner coordinates of the box. Default to 0.
451 Specify the width and height of the box, if 0 they are interpreted as
452 the input width and height. Default to 0.
455 Specify the color of the box to write, it can be the name of a color
456 (case insensitive match) or a 0xRRGGBB[AA] sequence.
459 Follow some examples:
461 # draw a black box around the edge of the input image
464 # draw a box with color red and an opacity of 50%
465 drawbox=10:20:200:60:red@@0.5"
470 Draw text string or text from specified file on top of video using the
473 To enable compilation of this filter you need to configure FFmpeg with
474 @code{--enable-libfreetype}.
476 The filter also recognizes strftime() sequences in the provided text
477 and expands them accordingly. Check the documentation of strftime().
479 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
482 The description of the accepted parameters follows.
487 The font file to be used for drawing text. Path must be included.
488 This parameter is mandatory.
491 The text string to be drawn. The text must be a sequence of UTF-8
493 This parameter is mandatory if no file is specified with the parameter
497 A text file containing text to be drawn. The text must be a sequence
498 of UTF-8 encoded characters.
500 This parameter is mandatory if no text string is specified with the
501 parameter @var{text}.
503 If both text and textfile are specified, an error is thrown.
506 The offsets where text will be drawn within the video frame.
507 Relative to the top/left border of the output image.
509 The default value of @var{x} and @var{y} is 0.
512 The font size to be used for drawing text.
513 The default value of @var{fontsize} is 16.
516 The color to be used for drawing fonts.
517 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
518 (e.g. "0xff000033"), possibly followed by an alpha specifier.
519 The default value of @var{fontcolor} is "black".
522 The color to be used for drawing box around text.
523 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
524 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
525 The default value of @var{boxcolor} is "white".
528 Used to draw a box around text using background color.
529 Value should be either 1 (enable) or 0 (disable).
530 The default value of @var{box} is 0.
532 @item shadowx, shadowy
533 The x and y offsets for the text shadow position with respect to the
534 position of the text. They can be either positive or negative
535 values. Default value for both is "0".
538 The color to be used for drawing a shadow behind the drawn text. It
539 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
540 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
541 The default value of @var{shadowcolor} is "black".
544 Flags to be used for loading the fonts.
546 The flags map the corresponding flags supported by libfreetype, and are
547 a combination of the following values:
554 @item vertical_layout
558 @item ignore_global_advance_width
560 @item ignore_transform
567 Default value is "render".
569 For more information consult the documentation for the FT_LOAD_*
573 The size in number of spaces to use for rendering the tab.
577 For example the command:
579 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
582 will draw "Test Text" with font FreeSerif, using the default values
583 for the optional parameters.
587 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
588 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
591 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
592 and y=50 (counting from the top-left corner of the screen), text is
593 yellow with a red box around it. Both the text and the box have an
596 Note that the double quotes are not necessary if spaces are not used
597 within the parameter list.
599 For more information about libfreetype, check:
600 @url{http://www.freetype.org/}.
604 Apply fade-in/out effect to input video.
606 It accepts the parameters:
607 @var{type}:@var{start_frame}:@var{nb_frames}
609 @var{type} specifies if the effect type, can be either "in" for
610 fade-in, or "out" for a fade-out effect.
612 @var{start_frame} specifies the number of the start frame for starting
613 to apply the fade effect.
615 @var{nb_frames} specifies the number of frames for which the fade
616 effect has to last. At the end of the fade-in effect the output video
617 will have the same intensity as the input video, at the end of the
618 fade-out transition the output video will be completely black.
620 A few usage examples follow, usable too as test scenarios.
622 # fade in first 30 frames of video
625 # fade out last 45 frames of a 200-frame video
628 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
629 fade=in:0:25, fade=out:975:25
631 # make first 5 frames black, then fade in from frame 5-24
637 Transform the field order of the input video.
639 It accepts one parameter which specifies the required field order that
640 the input interlaced video will be transformed to. The parameter can
641 assume one of the following values:
645 output bottom field first
647 output top field first
650 Default value is "tff".
652 Transformation is achieved by shifting the picture content up or down
653 by one line, and filling the remaining line with appropriate picture content.
654 This method is consistent with most broadcast field order converters.
656 If the input video is not flagged as being interlaced, or it is already
657 flagged as being of the required output field order then this filter does
658 not alter the incoming video.
660 This filter is very useful when converting to or from PAL DV material,
661 which is bottom field first.
665 ./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
670 Buffer input images and send them when they are requested.
672 This filter is mainly useful when auto-inserted by the libavfilter
675 The filter does not take parameters.
679 Convert the input video to one of the specified pixel formats.
680 Libavfilter will try to pick one that is supported for the input to
683 The filter accepts a list of pixel format names, separated by ":",
684 for example "yuv420p:monow:rgb24".
686 Some examples follow:
688 # convert the input video to the format "yuv420p"
691 # convert the input video to any of the formats in the list
692 format=yuv420p:yuv444p:yuv410p
698 Apply a frei0r effect to the input video.
700 To enable compilation of this filter you need to install the frei0r
701 header and configure Libav with --enable-frei0r.
703 The filter supports the syntax:
705 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
708 @var{filter_name} is the name to the frei0r effect to load. If the
709 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
710 is searched in each one of the directories specified by the colon
711 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
712 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
713 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
715 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
716 for the frei0r effect.
718 A frei0r effect parameter can be a boolean (whose values are specified
719 with "y" and "n"), a double, a color (specified by the syntax
720 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
721 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
722 description), a position (specified by the syntax @var{X}/@var{Y},
723 @var{X} and @var{Y} being float numbers) and a string.
725 The number and kind of parameters depend on the loaded effect. If an
726 effect parameter is not specified the default value is set.
728 Some examples follow:
730 # apply the distort0r effect, set the first two double parameters
731 frei0r=distort0r:0.5:0.01
733 # apply the colordistance effect, takes a color as first parameter
734 frei0r=colordistance:0.2/0.3/0.4
735 frei0r=colordistance:violet
736 frei0r=colordistance:0x112233
738 # apply the perspective effect, specify the top left and top right
740 frei0r=perspective:0.2/0.2:0.8/0.2
743 For more information see:
744 @url{http://piksel.org/frei0r}
748 Fix the banding artifacts that are sometimes introduced into nearly flat
749 regions by truncation to 8bit colordepth.
750 Interpolate the gradients that should go where the bands are, and
753 This filter is designed for playback only. Do not use it prior to
754 lossy compression, because compression tends to lose the dither and
755 bring back the bands.
757 The filter takes two optional parameters, separated by ':':
758 @var{strength}:@var{radius}
760 @var{strength} is the maximum amount by which the filter will change
761 any one pixel. Also the threshold for detecting nearly flat
762 regions. Acceptable values range from .51 to 255, default value is
763 1.2, out-of-range values will be clipped to the valid range.
765 @var{radius} is the neighborhood to fit the gradient to. A larger
766 radius makes for smoother gradients, but also prevents the filter from
767 modifying the pixels near detailed regions. Acceptable values are
768 8-32, default value is 16, out-of-range values will be clipped to the
781 Flip the input video horizontally.
783 For example to horizontally flip the video in input with
786 ffmpeg -i in.avi -vf "hflip" out.avi
791 High precision/quality 3d denoise filter. This filter aims to reduce
792 image noise producing smooth images and making still images really
793 still. It should enhance compressibility.
795 It accepts the following optional parameters:
796 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
800 a non-negative float number which specifies spatial luma strength,
804 a non-negative float number which specifies spatial chroma strength,
805 defaults to 3.0*@var{luma_spatial}/4.0
808 a float number which specifies luma temporal strength, defaults to
809 6.0*@var{luma_spatial}/4.0
812 a float number which specifies chroma temporal strength, defaults to
813 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
816 @section lut, lutrgb, lutyuv
818 Compute a look-up table for binding each pixel component input value
819 to an output value, and apply it to input video.
821 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
822 to an RGB input video.
824 These filters accept in input a ":"-separated list of options, which
825 specify the expressions used for computing the lookup table for the
826 corresponding pixel component values.
828 The @var{lut} filter requires either YUV or RGB pixel formats in
829 input, and accepts the options:
831 @var{c0} (first pixel component)
832 @var{c1} (second pixel component)
833 @var{c2} (third pixel component)
834 @var{c3} (fourth pixel component, corresponds to the alpha component)
837 The exact component associated to each option depends on the format in
840 The @var{lutrgb} filter requires RGB pixel formats in input, and
843 @var{r} (red component)
844 @var{g} (green component)
845 @var{b} (blue component)
846 @var{a} (alpha component)
849 The @var{lutyuv} filter requires YUV pixel formats in input, and
852 @var{y} (Y/luminance component)
853 @var{u} (U/Cb component)
854 @var{v} (V/Cr component)
855 @var{a} (alpha component)
858 The expressions can contain the following constants and functions:
862 the corresponding mathematical approximated values for e
863 (euler number), pi (greek PI), PHI (golden ratio)
866 the input width and heigth
869 input value for the pixel component
872 the input value clipped in the @var{minval}-@var{maxval} range
875 maximum value for the pixel component
878 minimum value for the pixel component
881 the negated value for the pixel component value clipped in the
882 @var{minval}-@var{maxval} range , it corresponds to the expression
883 "maxval-clipval+minval"
886 the computed value in @var{val} clipped in the
887 @var{minval}-@var{maxval} range
889 @item gammaval(gamma)
890 the computed gamma correction value of the pixel component value
891 clipped in the @var{minval}-@var{maxval} range, corresponds to the
893 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
897 All expressions default to "val".
899 Some examples follow:
902 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
903 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
905 # the above is the same as
906 lutrgb="r=negval:g=negval:b=negval"
907 lutyuv="y=negval:u=negval:v=negval"
912 # remove chroma components, turns the video into a graytone image
915 # apply a luma burning effect
918 # remove green and blue components
921 # set a constant alpha channel value on input
922 format=rgba,lutrgb=a="maxval-minval/2"
924 # correct luminance gamma by a 0.5 factor
925 lutyuv=y=gammaval(0.5)
932 This filter accepts an integer in input, if non-zero it negates the
933 alpha component (if available). The default value in input is 0.
935 Force libavfilter not to use any of the specified pixel formats for the
936 input to the next filter.
938 The filter accepts a list of pixel format names, separated by ":",
939 for example "yuv420p:monow:rgb24".
941 Some examples follow:
943 # force libavfilter to use a format different from "yuv420p" for the
944 # input to the vflip filter
945 noformat=yuv420p,vflip
947 # convert the input video to any of the formats not contained in the list
948 noformat=yuv420p:yuv444p:yuv410p
953 Pass the video source unchanged to the output.
957 Apply video transform using libopencv.
959 To enable this filter install libopencv library and headers and
960 configure Libav with --enable-libopencv.
962 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
964 @var{filter_name} is the name of the libopencv filter to apply.
966 @var{filter_params} specifies the parameters to pass to the libopencv
967 filter. If not specified the default values are assumed.
969 Refer to the official libopencv documentation for more precise
971 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
973 Follows the list of supported libopencv filters.
978 Dilate an image by using a specific structuring element.
979 This filter corresponds to the libopencv function @code{cvDilate}.
981 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
983 @var{struct_el} represents a structuring element, and has the syntax:
984 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
986 @var{cols} and @var{rows} represent the number of colums and rows of
987 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
988 point, and @var{shape} the shape for the structuring element, and
989 can be one of the values "rect", "cross", "ellipse", "custom".
991 If the value for @var{shape} is "custom", it must be followed by a
992 string of the form "=@var{filename}". The file with name
993 @var{filename} is assumed to represent a binary image, with each
994 printable character corresponding to a bright pixel. When a custom
995 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
996 or columns and rows of the read file are assumed instead.
998 The default value for @var{struct_el} is "3x3+0x0/rect".
1000 @var{nb_iterations} specifies the number of times the transform is
1001 applied to the image, and defaults to 1.
1003 Follow some example:
1005 # use the default values
1008 # dilate using a structuring element with a 5x5 cross, iterate two times
1009 ocv=dilate=5x5+2x2/cross:2
1011 # read the shape from the file diamond.shape, iterate two times
1012 # the file diamond.shape may contain a pattern of characters like this:
1018 # the specified cols and rows are ignored (but not the anchor point coordinates)
1019 ocv=0x0+2x2/custom=diamond.shape:2
1024 Erode an image by using a specific structuring element.
1025 This filter corresponds to the libopencv function @code{cvErode}.
1027 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1028 with the same syntax and semantics as the @ref{dilate} filter.
1032 Smooth the input video.
1034 The filter takes the following parameters:
1035 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1037 @var{type} is the type of smooth filter to apply, and can be one of
1038 the following values: "blur", "blur_no_scale", "median", "gaussian",
1039 "bilateral". The default value is "gaussian".
1041 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1042 parameters whose meanings depend on smooth type. @var{param1} and
1043 @var{param2} accept integer positive values or 0, @var{param3} and
1044 @var{param4} accept float values.
1046 The default value for @var{param1} is 3, the default value for the
1047 other parameters is 0.
1049 These parameters correspond to the parameters assigned to the
1050 libopencv function @code{cvSmooth}.
1054 Overlay one video on top of another.
1056 It takes two inputs and one output, the first input is the "main"
1057 video on which the second input is overlayed.
1059 It accepts the parameters: @var{x}:@var{y}.
1061 @var{x} is the x coordinate of the overlayed video on the main video,
1062 @var{y} is the y coordinate. The parameters are expressions containing
1063 the following parameters:
1066 @item main_w, main_h
1067 main input width and height
1070 same as @var{main_w} and @var{main_h}
1072 @item overlay_w, overlay_h
1073 overlay input width and height
1076 same as @var{overlay_w} and @var{overlay_h}
1079 Be aware that frames are taken from each input video in timestamp
1080 order, hence, if their initial timestamps differ, it is a a good idea
1081 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1082 have them begin in the same zero timestamp, as it does the example for
1083 the @var{movie} filter.
1085 Follow some examples:
1087 # draw the overlay at 10 pixels from the bottom right
1088 # corner of the main video.
1089 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1091 # insert a transparent PNG logo in the bottom left corner of the input
1092 movie=logo.png [logo];
1093 [in][logo] overlay=10:main_h-overlay_h-10 [out]
1095 # insert 2 different transparent PNG logos (second logo on bottom
1097 movie=logo1.png [logo1];
1098 movie=logo2.png [logo2];
1099 [in][logo1] overlay=10:H-h-10 [in+logo1];
1100 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
1102 # add a transparent color layer on top of the main video,
1103 # WxH specifies the size of the main input to the overlay filter
1104 color=red@.3:WxH [over]; [in][over] overlay [out]
1107 You can chain togheter more overlays but the efficiency of such
1108 approach is yet to be tested.
1112 Add paddings to the input image, and places the original input at the
1113 given coordinates @var{x}, @var{y}.
1115 It accepts the following parameters:
1116 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1118 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1119 expressions containing the following constants:
1123 the corresponding mathematical approximated values for e
1124 (euler number), pi (greek PI), phi (golden ratio)
1127 the input video width and height
1130 same as @var{in_w} and @var{in_h}
1133 the output width and height, that is the size of the padded area as
1134 specified by the @var{width} and @var{height} expressions
1137 same as @var{out_w} and @var{out_h}
1140 x and y offsets as specified by the @var{x} and @var{y}
1141 expressions, or NAN if not yet specified
1144 input display aspect ratio, same as @var{iw} / @var{ih}
1147 horizontal and vertical chroma subsample values. For example for the
1148 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1151 Follows the description of the accepted parameters.
1156 Specify the size of the output image with the paddings added. If the
1157 value for @var{width} or @var{height} is 0, the corresponding input size
1158 is used for the output.
1160 The @var{width} expression can reference the value set by the
1161 @var{height} expression, and viceversa.
1163 The default value of @var{width} and @var{height} is 0.
1167 Specify the offsets where to place the input image in the padded area
1168 with respect to the top/left border of the output image.
1170 The @var{x} expression can reference the value set by the @var{y}
1171 expression, and viceversa.
1173 The default value of @var{x} and @var{y} is 0.
1177 Specify the color of the padded area, it can be the name of a color
1178 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1180 The default value of @var{color} is "black".
1184 Some examples follow:
1187 # Add paddings with color "violet" to the input video. Output video
1188 # size is 640x480, the top-left corner of the input video is placed at
1190 pad=640:480:0:40:violet
1192 # pad the input to get an output with dimensions increased bt 3/2,
1193 # and put the input video at the center of the padded area
1194 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1196 # pad the input to get a squared output with size equal to the maximum
1197 # value between the input width and height, and put the input video at
1198 # the center of the padded area
1199 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1201 # pad the input to get a final w/h ratio of 16:9
1202 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1204 # double output size and put the input video in the bottom-right
1205 # corner of the output padded area
1206 pad="2*iw:2*ih:ow-iw:oh-ih"
1209 @section pixdesctest
1211 Pixel format descriptor test filter, mainly useful for internal
1212 testing. The output video should be equal to the input video.
1216 format=monow, pixdesctest
1219 can be used to test the monowhite pixel format descriptor definition.
1223 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1225 The parameters @var{width} and @var{height} are expressions containing
1226 the following constants:
1230 the corresponding mathematical approximated values for e
1231 (euler number), pi (greek PI), phi (golden ratio)
1234 the input width and height
1237 same as @var{in_w} and @var{in_h}
1240 the output (cropped) width and height
1243 same as @var{out_w} and @var{out_h}
1246 input display aspect ratio, same as @var{iw} / @var{ih}
1249 input sample aspect ratio
1252 horizontal and vertical chroma subsample values. For example for the
1253 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1256 If the input image format is different from the format requested by
1257 the next filter, the scale filter will convert the input to the
1260 If the value for @var{width} or @var{height} is 0, the respective input
1261 size is used for the output.
1263 If the value for @var{width} or @var{height} is -1, the scale filter will
1264 use, for the respective output size, a value that maintains the aspect
1265 ratio of the input image.
1267 The default value of @var{width} and @var{height} is 0.
1269 Some examples follow:
1271 # scale the input video to a size of 200x100.
1274 # scale the input to 2x
1276 # the above is the same as
1279 # scale the input to half size
1282 # increase the width, and set the height to the same size
1285 # seek for Greek harmony
1289 # increase the height, and set the width to 3/2 of the height
1292 # increase the size, but make the size a multiple of the chroma
1293 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1295 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1296 scale='min(500\, iw*3/2):-1'
1300 Select frames to pass in output.
1302 It accepts in input an expression, which is evaluated for each input
1303 frame. If the expression is evaluated to a non-zero value, the frame
1304 is selected and passed to the output, otherwise it is discarded.
1306 The expression can contain the following constants:
1319 the sequential number of the filtered frame, starting from 0
1322 the sequential number of the selected frame, starting from 0
1324 @item prev_selected_n
1325 the sequential number of the last selected frame, NAN if undefined
1328 timebase of the input timestamps
1331 the PTS (Presentation TimeStamp) of the filtered video frame,
1332 expressed in @var{TB} units, NAN if undefined
1335 the PTS (Presentation TimeStamp) of the filtered video frame,
1336 expressed in seconds, NAN if undefined
1339 the PTS of the previously filtered video frame, NAN if undefined
1341 @item prev_selected_pts
1342 the PTS of the last previously filtered video frame, NAN if undefined
1344 @item prev_selected_t
1345 the PTS of the last previously selected video frame, NAN if undefined
1348 the PTS of the first video frame in the video, NAN if undefined
1351 the time of the first video frame in the video, NAN if undefined
1354 the type of the filtered frame, can assume one of the following
1366 @item interlace_type
1367 the frame interlace type, can assume one of the following values:
1370 the frame is progressive (not interlaced)
1372 the frame is top-field-first
1374 the frame is bottom-field-first
1378 1 if the filtered frame is a key-frame, 0 otherwise
1381 the position in the file of the filtered frame, -1 if the information
1382 is not available (e.g. for synthetic video)
1385 The default value of the select expression is "1".
1387 Some examples follow:
1390 # select all frames in input
1393 # the above is the same as:
1399 # select only I-frames
1400 select='eq(pict_type\,I)'
1402 # select one frame every 100
1403 select='not(mod(n\,100))'
1405 # select only frames contained in the 10-20 time interval
1406 select='gte(t\,10)*lte(t\,20)'
1408 # select only I frames contained in the 10-20 time interval
1409 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1411 # select frames with a minimum distance of 10 seconds
1412 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1418 Set the Display Aspect Ratio for the filter output video.
1420 This is done by changing the specified Sample (aka Pixel) Aspect
1421 Ratio, according to the following equation:
1422 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1424 Keep in mind that this filter does not modify the pixel dimensions of
1425 the video frame. Also the display aspect ratio set by this filter may
1426 be changed by later filters in the filterchain, e.g. in case of
1427 scaling or if another "setdar" or a "setsar" filter is applied.
1429 The filter accepts a parameter string which represents the wanted
1430 display aspect ratio.
1431 The parameter can be a floating point number string, or an expression
1432 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1433 numerator and denominator of the aspect ratio.
1434 If the parameter is not specified, it is assumed the value "0:1".
1436 For example to change the display aspect ratio to 16:9, specify:
1439 # the above is equivalent to
1443 See also the @ref{setsar} filter documentation.
1447 Change the PTS (presentation timestamp) of the input video frames.
1449 Accept in input an expression evaluated through the eval API, which
1450 can contain the following constants:
1454 the presentation timestamp in input
1466 the count of the input frame, starting from 0.
1469 the PTS of the first video frame
1472 tell if the current frame is interlaced
1475 original position in the file of the frame, or undefined if undefined
1476 for the current frame
1486 Some examples follow:
1489 # start counting PTS from zero
1501 # fixed rate 25 fps with some jitter
1502 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1508 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1510 Note that as a consequence of the application of this filter, the
1511 output display aspect ratio will change according to the following
1513 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1515 Keep in mind that the sample aspect ratio set by this filter may be
1516 changed by later filters in the filterchain, e.g. if another "setsar"
1517 or a "setdar" filter is applied.
1519 The filter accepts a parameter string which represents the wanted
1520 sample aspect ratio.
1521 The parameter can be a floating point number string, or an expression
1522 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1523 numerator and denominator of the aspect ratio.
1524 If the parameter is not specified, it is assumed the value "0:1".
1526 For example to change the sample aspect ratio to 10:11, specify:
1533 Set the timebase to use for the output frames timestamps.
1534 It is mainly useful for testing timebase configuration.
1536 It accepts in input an arithmetic expression representing a rational.
1537 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1538 default timebase), and "intb" (the input timebase).
1540 The default value for the input is "intb".
1542 Follow some examples.
1545 # set the timebase to 1/25
1548 # set the timebase to 1/10
1551 #set the timebase to 1001/1000
1554 #set the timebase to 2*intb
1557 #set the default timebase value
1563 Show a line containing various information for each input video frame.
1564 The input video is not modified.
1566 The shown line contains a sequence of key/value pairs of the form
1567 @var{key}:@var{value}.
1569 A description of each shown parameter follows:
1573 sequential number of the input frame, starting from 0
1576 Presentation TimeStamp of the input frame, expressed as a number of
1577 time base units. The time base unit depends on the filter input pad.
1580 Presentation TimeStamp of the input frame, expressed as a number of
1584 position of the frame in the input stream, -1 if this information in
1585 unavailable and/or meanigless (for example in case of synthetic video)
1591 sample aspect ratio of the input frame, expressed in the form
1595 size of the input frame, expressed in the form
1596 @var{width}x@var{height}
1599 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1600 for bottom field first)
1603 1 if the frame is a key frame, 0 otherwise
1606 picture type of the input frame ("I" for an I-frame, "P" for a
1607 P-frame, "B" for a B-frame, "?" for unknown type).
1608 Check also the documentation of the @code{AVPictureType} enum and of
1609 the @code{av_get_picture_type_char} function defined in
1610 @file{libavutil/avutil.h}.
1613 Adler-32 checksum of all the planes of the input frame
1615 @item plane_checksum
1616 Adler-32 checksum of each plane of the input frame, expressed in the form
1617 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
1622 Pass the images of input video on to next video filter as multiple
1626 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
1629 The filter accepts the slice height as parameter. If the parameter is
1630 not specified it will use the default value of 16.
1632 Adding this in the beginning of filter chains should make filtering
1633 faster due to better use of the memory cache.
1637 Transpose rows with columns in the input video and optionally flip it.
1639 It accepts a parameter representing an integer, which can assume the
1644 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1652 Rotate by 90 degrees clockwise, that is:
1660 Rotate by 90 degrees counterclockwise, that is:
1668 Rotate by 90 degrees clockwise and vertically flip, that is:
1678 Sharpen or blur the input video.
1680 It accepts the following parameters:
1681 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1683 Negative values for the amount will blur the input video, while positive
1684 values will sharpen. All parameters are optional and default to the
1685 equivalent of the string '5:5:1.0:5:5:0.0'.
1690 Set the luma matrix horizontal size. It can be an integer between 3
1691 and 13, default value is 5.
1694 Set the luma matrix vertical size. It can be an integer between 3
1695 and 13, default value is 5.
1698 Set the luma effect strength. It can be a float number between -2.0
1699 and 5.0, default value is 1.0.
1701 @item chroma_msize_x
1702 Set the chroma matrix horizontal size. It can be an integer between 3
1703 and 13, default value is 5.
1705 @item chroma_msize_y
1706 Set the chroma matrix vertical size. It can be an integer between 3
1707 and 13, default value is 5.
1710 Set the chroma effect strength. It can be a float number between -2.0
1711 and 5.0, default value is 0.0.
1716 # Strong luma sharpen effect parameters
1719 # Strong blur of both luma and chroma parameters
1720 unsharp=7:7:-2:7:7:-2
1722 # Use the default values with @command{ffmpeg}
1723 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
1728 Flip the input video vertically.
1731 ./ffmpeg -i in.avi -vf "vflip" out.avi
1736 Deinterlace the input video ("yadif" means "yet another deinterlacing
1739 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
1741 @var{mode} specifies the interlacing mode to adopt, accepts one of the
1746 output 1 frame for each frame
1748 output 1 frame for each field
1750 like 0 but skips spatial interlacing check
1752 like 1 but skips spatial interlacing check
1757 @var{parity} specifies the picture field parity assumed for the input
1758 interlaced video, accepts one of the following values:
1762 assume top field first
1764 assume bottom field first
1766 enable automatic detection
1769 Default value is -1.
1770 If interlacing is unknown or decoder does not export this information,
1771 top field first will be assumed.
1773 @var{auto] specifies if deinterlacer should trust the interlaced flag
1774 and only deinterlace frames marked as interlaced
1778 deinterlace all frames
1780 only deinterlace frames marked as interlaced
1785 @c man end VIDEO FILTERS
1787 @chapter Video Sources
1788 @c man begin VIDEO SOURCES
1790 Below is a description of the currently available video sources.
1794 Buffer video frames, and make them available to the filter chain.
1796 This source is mainly intended for a programmatic use, in particular
1797 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1799 It accepts the following parameters:
1800 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
1802 All the parameters need to be explicitely defined.
1804 Follows the list of the accepted parameters.
1809 Specify the width and height of the buffered video frames.
1811 @item pix_fmt_string
1812 A string representing the pixel format of the buffered video frames.
1813 It may be a number corresponding to a pixel format, or a pixel format
1816 @item timebase_num, timebase_den
1817 Specify numerator and denomitor of the timebase assumed by the
1818 timestamps of the buffered frames.
1820 @item sample_aspect_ratio.num, sample_aspect_ratio.den
1821 Specify numerator and denominator of the sample aspect ratio assumed
1822 by the video frames.
1827 buffer=320:240:yuv410p:1:24:1:1
1830 will instruct the source to accept video frames with size 320x240 and
1831 with format "yuv410p", assuming 1/24 as the timestamps timebase and
1832 square pixels (1:1 sample aspect ratio).
1833 Since the pixel format with name "yuv410p" corresponds to the number 6
1834 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1835 this example corresponds to:
1837 buffer=320:240:6:1:24
1842 Provide an uniformly colored input.
1844 It accepts the following parameters:
1845 @var{color}:@var{frame_size}:@var{frame_rate}
1847 Follows the description of the accepted parameters.
1852 Specify the color of the source. It can be the name of a color (case
1853 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1854 alpha specifier. The default value is "black".
1857 Specify the size of the sourced video, it may be a string of the form
1858 @var{width}x@var{height}, or the name of a size abbreviation. The
1859 default value is "320x240".
1862 Specify the frame rate of the sourced video, as the number of frames
1863 generated per second. It has to be a string in the format
1864 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1865 number or a valid video frame rate abbreviation. The default value is
1870 For example the following graph description will generate a red source
1871 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1872 frames per second, which will be overlayed over the source connected
1873 to the pad with identifier "in".
1876 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1881 Read a video stream from a movie container.
1883 It accepts the syntax: @var{movie_name}[:@var{options}] where
1884 @var{movie_name} is the name of the resource to read (not necessarily
1885 a file but also a device or a stream accessed through some protocol),
1886 and @var{options} is an optional sequence of @var{key}=@var{value}
1887 pairs, separated by ":".
1889 The description of the accepted options follows.
1893 @item format_name, f
1894 Specifies the format assumed for the movie to read, and can be either
1895 the name of a container or an input device. If not specified the
1896 format is guessed from @var{movie_name} or by probing.
1898 @item seek_point, sp
1899 Specifies the seek point in seconds, the frames will be output
1900 starting from this seek point, the parameter is evaluated with
1901 @code{av_strtod} so the numerical value may be suffixed by an IS
1902 postfix. Default value is "0".
1904 @item stream_index, si
1905 Specifies the index of the video stream to read. If the value is -1,
1906 the best suited video stream will be automatically selected. Default
1911 This filter allows to overlay a second video on top of main input of
1912 a filtergraph as shown in this graph:
1914 input -----------> deltapts0 --> overlay --> output
1917 movie --> scale--> deltapts1 -------+
1920 Some examples follow:
1922 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1923 # on top of the input labelled as "in".
1924 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1925 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1927 # read from a video4linux2 device, and overlay it on top of the input
1929 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1930 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1936 Null video source, never return images. It is mainly useful as a
1937 template and to be employed in analysis / debugging tools.
1939 It accepts as optional parameter a string of the form
1940 @var{width}:@var{height}:@var{timebase}.
1942 @var{width} and @var{height} specify the size of the configured
1943 source. The default values of @var{width} and @var{height} are
1944 respectively 352 and 288 (corresponding to the CIF size format).
1946 @var{timebase} specifies an arithmetic expression representing a
1947 timebase. The expression can contain the constants "PI", "E", "PHI",
1948 "AVTB" (the default timebase), and defaults to the value "AVTB".
1952 Provide a frei0r source.
1954 To enable compilation of this filter you need to install the frei0r
1955 header and configure Libav with --enable-frei0r.
1957 The source supports the syntax:
1959 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1962 @var{size} is the size of the video to generate, may be a string of the
1963 form @var{width}x@var{height} or a frame size abbreviation.
1964 @var{rate} is the rate of the video to generate, may be a string of
1965 the form @var{num}/@var{den} or a frame rate abbreviation.
1966 @var{src_name} is the name to the frei0r source to load. For more
1967 information regarding frei0r and how to set the parameters read the
1968 section @ref{frei0r} in the description of the video filters.
1970 Some examples follow:
1972 # generate a frei0r partik0l source with size 200x200 and framerate 10
1973 # which is overlayed on the overlay filter main input
1974 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1977 @section rgbtestsrc, testsrc
1979 The @code{rgbtestsrc} source generates an RGB test pattern useful for
1980 detecting RGB vs BGR issues. You should see a red, green and blue
1981 stripe from top to bottom.
1983 The @code{testsrc} source generates a test video pattern, showing a
1984 color pattern, a scrolling gradient and a timestamp. This is mainly
1985 intended for testing purposes.
1987 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
1988 separated by ":". The description of the accepted options follows.
1993 Specify the size of the sourced video, it may be a string of the form
1994 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1995 default value is "320x240".
1998 Specify the frame rate of the sourced video, as the number of frames
1999 generated per second. It has to be a string in the format
2000 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2001 number or a valid video frame rate abbreviation. The default value is
2005 Set the sample aspect ratio of the sourced video.
2008 Set the video duration of the sourced video. The accepted syntax is:
2010 [-]HH[:MM[:SS[.m...]]]
2013 See also the function @code{av_parse_time()}.
2015 If not specified, or the expressed duration is negative, the video is
2016 supposed to be generated forever.
2019 For example the following:
2021 testsrc=duration=5.3:size=qcif:rate=10
2024 will generate a video with a duration of 5.3 seconds, with size
2025 176x144 and a framerate of 10 frames per second.
2027 @c man end VIDEO SOURCES
2029 @chapter Video Sinks
2030 @c man begin VIDEO SINKS
2032 Below is a description of the currently available video sinks.
2036 Null video sink, do absolutely nothing with the input video. It is
2037 mainly useful as a template and to be employed in analysis / debugging
2040 @c man end VIDEO SINKS