1 @chapter Filtergraph description
2 @c man begin FILTERGRAPH DESCRIPTION
4 A filtergraph is a directed graph of connected filters. It can contain
5 cycles, and there can be multiple links between a pair of
6 filters. Each link has one input pad on one side connecting it to one
7 filter from which it takes its input, and one output pad on the other
8 side connecting it to the one filter accepting its output.
10 Each filter in a filtergraph is an instance of a filter class
11 registered in the application, which defines the features and the
12 number of input and output pads of the filter.
14 A filter with no input pads is called a "source", a filter with no
15 output pads is called a "sink".
17 @section Filtergraph syntax
19 A filtergraph can be represented using a textual representation, which
20 is recognized by the @code{-vf} and @code{-af} options of the ff*
21 tools, and by the @code{avfilter_graph_parse()} function defined in
22 @file{libavfilter/avfiltergraph.h}.
24 A filterchain consists of a sequence of connected filters, each one
25 connected to the previous one in the sequence. A filterchain is
26 represented by a list of ","-separated filter descriptions.
28 A filtergraph consists of a sequence of filterchains. A sequence of
29 filterchains is represented by a list of ";"-separated filterchain
32 A filter is represented by a string of the form:
33 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
35 @var{filter_name} is the name of the filter class of which the
36 described filter is an instance of, and has to be the name of one of
37 the filter classes registered in the program.
38 The name of the filter class is optionally followed by a string
41 @var{arguments} is a string which contains the parameters used to
42 initialize the filter instance, and are described in the filter
45 The list of arguments can be quoted using the character "'" as initial
46 and ending mark, and the character '\' for escaping the characters
47 within the quoted text; otherwise the argument string is considered
48 terminated when the next special character (belonging to the set
49 "[]=;,") is encountered.
51 The name and arguments of the filter are optionally preceded and
52 followed by a list of link labels.
53 A link label allows to name a link and associate it to a filter output
54 or input pad. The preceding labels @var{in_link_1}
55 ... @var{in_link_N}, are associated to the filter input pads,
56 the following labels @var{out_link_1} ... @var{out_link_M}, are
57 associated to the output pads.
59 When two link labels with the same name are found in the
60 filtergraph, a link between the corresponding input and output pad is
63 If an output pad is not labelled, it is linked by default to the first
64 unlabelled input pad of the next filter in the filterchain.
65 For example in the filterchain:
67 nullsrc, split[L1], [L2]overlay, nullsink
69 the split filter instance has two output pads, and the overlay filter
70 instance two input pads. The first output pad of split is labelled
71 "L1", the first input pad of overlay is labelled "L2", and the second
72 output pad of split is linked to the second input pad of overlay,
73 which are both unlabelled.
75 In a complete filterchain all the unlabelled filter input and output
76 pads must be connected. A filtergraph is considered valid if all the
77 filter input and output pads of all the filterchains are connected.
79 Follows a BNF description for the filtergraph syntax:
81 @var{NAME} ::= sequence of alphanumeric characters and '_'
82 @var{LINKLABEL} ::= "[" @var{NAME} "]"
83 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
84 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
85 @var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
86 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
87 @var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
90 @c man end FILTERGRAPH DESCRIPTION
92 @chapter Audio Filters
93 @c man begin AUDIO FILTERS
95 When you configure your FFmpeg build, you can disable any of the
96 existing filters using --disable-filters.
97 The configure output will show the audio filters included in your
100 Below is a description of the currently available audio filters.
104 Convert the input audio format to the specified formats.
106 The filter accepts a string of the form:
107 "@var{sample_format}:@var{channel_layout}:@var{packing_format}".
109 @var{sample_format} specifies the sample format, and can be a string or
110 the corresponding numeric value defined in @file{libavutil/samplefmt.h}.
112 @var{channel_layout} specifies the channel layout, and can be a string
113 or the corresponding number value defined in @file{libavutil/chlayout.h}.
115 @var{packing_format} specifies the type of packing in output, can be one
116 of "planar" or "packed", or the corresponding numeric values "0" or "1".
118 The special parameter "auto", signifies that the filter will
119 automatically select the output format depending on the output filter.
121 Some examples follow.
125 Convert input to unsigned 8-bit, stereo, packed:
127 aconvert=u8:stereo:packed
131 Convert input to unsigned 8-bit, automatically select out channel layout
134 aconvert=u8:auto:auto
140 Convert the input audio to one of the specified formats. The framework will
141 negotiate the most appropriate format to minimize conversions.
143 The filter accepts three lists of formats, separated by ":", in the form:
144 "@var{sample_formats}:@var{channel_layouts}:@var{packing_formats}".
146 Elements in each list are separated by "," which has to be escaped in the
147 filtergraph specification.
149 The special parameter "all", in place of a list of elements, signifies all
152 Some examples follow:
154 aformat=u8\\,s16:mono:packed
156 aformat=s16:mono\\,stereo:all
161 Pass the audio source unchanged to the output.
165 Resample the input audio to the specified sample rate.
167 The filter accepts exactly one parameter, the output sample rate. If not
168 specified then the filter will automatically convert between its input
169 and output sample rates.
171 For example, to resample the input audio to 44100Hz:
178 Show a line containing various information for each input audio frame.
179 The input audio is not modified.
181 The shown line contains a sequence of key/value pairs of the form
182 @var{key}:@var{value}.
184 A description of each shown parameter follows:
188 sequential number of the input frame, starting from 0
191 presentation TimeStamp of the input frame, expressed as a number of
192 time base units. The time base unit depends on the filter input pad, and
193 is usually 1/@var{sample_rate}.
196 presentation TimeStamp of the input frame, expressed as a number of
200 position of the frame in the input stream, -1 if this information in
201 unavailable and/or meanigless (for example in case of synthetic audio)
207 channel layout description
210 number of samples (per each channel) contained in the filtered frame
213 sample rate for the audio frame
216 if the packing format is planar, 0 if packed
219 Adler-32 checksum of all the planes of the input frame
222 Adler-32 checksum for each input frame plane, expressed in the form
223 "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5} @var{c6} @var{c7}]"
226 @c man end AUDIO FILTERS
228 @chapter Audio Sources
229 @c man begin AUDIO SOURCES
231 Below is a description of the currently available audio sources.
235 Buffer audio frames, and make them available to the filter chain.
237 This source is mainly intended for a programmatic use, in particular
238 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
240 It accepts the following mandatory parameters:
241 @var{sample_rate}:@var{sample_fmt}:@var{channel_layout}:@var{packing}
246 The sample rate of the incoming audio buffers.
249 The sample format of the incoming audio buffers.
250 Either a sample format name or its corresponging integer representation from
251 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
254 The channel layout of the incoming audio buffers.
255 Either a channel layout name from channel_layout_map in
256 @file{libavutil/audioconvert.c} or its corresponding integer representation
257 from the AV_CH_LAYOUT_* macros in @file{libavutil/audioconvert.h}
260 Either "packed" or "planar", or their integer representation: 0 or 1
267 abuffer=44100:s16:stereo:planar
270 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
271 Since the sample format with name "s16" corresponds to the number
272 1 and the "stereo" channel layout corresponds to the value 3, this is
280 Read an audio stream from a movie container.
282 It accepts the syntax: @var{movie_name}[:@var{options}] where
283 @var{movie_name} is the name of the resource to read (not necessarily
284 a file but also a device or a stream accessed through some protocol),
285 and @var{options} is an optional sequence of @var{key}=@var{value}
286 pairs, separated by ":".
288 The description of the accepted options follows.
293 Specify the format assumed for the movie to read, and can be either
294 the name of a container or an input device. If not specified the
295 format is guessed from @var{movie_name} or by probing.
298 Specify the seek point in seconds, the frames will be output
299 starting from this seek point, the parameter is evaluated with
300 @code{av_strtod} so the numerical value may be suffixed by an IS
301 postfix. Default value is "0".
303 @item stream_index, si
304 Specify the index of the audio stream to read. If the value is -1,
305 the best suited audio stream will be automatically selected. Default
312 Null audio source, return unprocessed audio frames. It is mainly useful
313 as a template and to be employed in analysis / debugging tools, or as
314 the source for filters which ignore the input data (for example the sox
317 It accepts an optional sequence of @var{key}=@var{value} pairs,
320 The description of the accepted options follows.
325 Specify the sample rate, and defaults to 44100.
327 @item channel_layout, cl
329 Specify the channel layout, and can be either an integer or a string
330 representing a channel layout. The default value of @var{channel_layout}
333 Check the channel_layout_map definition in
334 @file{libavcodec/audioconvert.c} for the mapping between strings and
335 channel layout values.
338 Set the number of samples per requested frames.
342 Follow some examples:
344 # set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
345 anullsrc=r=48000:cl=4
348 anullsrc=r=48000:cl=mono
351 @c man end AUDIO SOURCES
354 @c man begin AUDIO SINKS
356 Below is a description of the currently available audio sinks.
360 Buffer audio frames, and make them available to the end of filter chain.
362 This sink is mainly intended for programmatic use, in particular
363 through the interface defined in @file{libavfilter/buffersink.h}.
365 It requires a pointer to an AVABufferSinkContext structure, which
366 defines the incoming buffers' formats, to be passed as the opaque
367 parameter to @code{avfilter_init_filter} for initialization.
371 Null audio sink, do absolutely nothing with the input audio. It is
372 mainly useful as a template and to be employed in analysis / debugging
375 @c man end AUDIO SINKS
377 @chapter Video Filters
378 @c man begin VIDEO FILTERS
380 When you configure your FFmpeg build, you can disable any of the
381 existing filters using --disable-filters.
382 The configure output will show the video filters included in your
385 Below is a description of the currently available video filters.
389 Detect frames that are (almost) completely black. Can be useful to
390 detect chapter transitions or commercials. Output lines consist of
391 the frame number of the detected frame, the percentage of blackness,
392 the position in the file if known or -1 and the timestamp in seconds.
394 In order to display the output lines, you need to set the loglevel at
395 least to the AV_LOG_INFO value.
397 The filter accepts the syntax:
399 blackframe[=@var{amount}:[@var{threshold}]]
402 @var{amount} is the percentage of the pixels that have to be below the
403 threshold, and defaults to 98.
405 @var{threshold} is the threshold below which a pixel value is
406 considered black, and defaults to 32.
410 Apply boxblur algorithm to the input video.
412 This filter accepts the parameters:
413 @var{luma_radius}:@var{luma_power}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
415 Chroma and alpha parameters are optional, if not specified they default
416 to the corresponding values set for @var{luma_radius} and
419 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
420 the radius in pixels of the box used for blurring the corresponding
421 input plane. They are expressions, and can contain the following
425 the input width and heigth in pixels
428 the input chroma image width and height in pixels
431 horizontal and vertical chroma subsample values. For example for the
432 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
435 The radius must be a non-negative number, and must be not greater than
436 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
437 and of @code{min(cw,ch)/2} for the chroma planes.
439 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
440 how many times the boxblur filter is applied to the corresponding
443 Some examples follow:
448 Apply a boxblur filter with luma, chroma, and alpha radius
455 Set luma radius to 2, alpha and chroma radius to 0
461 Set luma and chroma radius to a fraction of the video dimension
463 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
470 Copy the input source unchanged to the output. Mainly useful for
475 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
477 The parameters are expressions containing the following constants:
481 the computed values for @var{x} and @var{y}. They are evaluated for
485 the input width and height
488 same as @var{in_w} and @var{in_h}
491 the output (cropped) width and height
494 same as @var{out_w} and @var{out_h}
497 same as @var{iw} / @var{ih}
500 input sample aspect ratio
503 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
506 horizontal and vertical chroma subsample values. For example for the
507 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
510 the number of input frame, starting from 0
513 the position in the file of the input frame, NAN if unknown
516 timestamp expressed in seconds, NAN if the input timestamp is unknown
520 The @var{out_w} and @var{out_h} parameters specify the expressions for
521 the width and height of the output (cropped) video. They are
522 evaluated just at the configuration of the filter.
524 The default value of @var{out_w} is "in_w", and the default value of
525 @var{out_h} is "in_h".
527 The expression for @var{out_w} may depend on the value of @var{out_h},
528 and the expression for @var{out_h} may depend on @var{out_w}, but they
529 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
530 evaluated after @var{out_w} and @var{out_h}.
532 The @var{x} and @var{y} parameters specify the expressions for the
533 position of the top-left corner of the output (non-cropped) area. They
534 are evaluated for each frame. If the evaluated value is not valid, it
535 is approximated to the nearest valid value.
537 The default value of @var{x} is "(in_w-out_w)/2", and the default
538 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
539 the center of the input image.
541 The expression for @var{x} may depend on @var{y}, and the expression
542 for @var{y} may depend on @var{x}.
544 Follow some examples:
546 # crop the central input area with size 100x100
549 # crop the central input area with size 2/3 of the input video
550 "crop=2/3*in_w:2/3*in_h"
552 # crop the input video central square
555 # delimit the rectangle with the top-left corner placed at position
556 # 100:100 and the right-bottom corner corresponding to the right-bottom
557 # corner of the input image.
558 crop=in_w-100:in_h-100:100:100
560 # crop 10 pixels from the left and right borders, and 20 pixels from
561 # the top and bottom borders
562 "crop=in_w-2*10:in_h-2*20"
564 # keep only the bottom right quarter of the input image
565 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
567 # crop height for getting Greek harmony
568 "crop=in_w:1/PHI*in_w"
571 "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)"
573 # erratic camera effect depending on timestamp
574 "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)"
576 # set x depending on the value of y
577 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
582 Auto-detect crop size.
584 Calculate necessary cropping parameters and prints the recommended
585 parameters through the logging system. The detected dimensions
586 correspond to the non-black area of the input video.
588 It accepts the syntax:
590 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
596 Threshold, which can be optionally specified from nothing (0) to
597 everything (255), defaults to 24.
600 Value which the width/height should be divisible by, defaults to
601 16. The offset is automatically adjusted to center the video. Use 2 to
602 get only even dimensions (needed for 4:2:2 video). 16 is best when
603 encoding to most video codecs.
606 Counter that determines after how many frames cropdetect will reset
607 the previously detected largest video area and start over to detect
608 the current optimal crop area. Defaults to 0.
610 This can be useful when channel logos distort the video area. 0
611 indicates never reset and return the largest area encountered during
617 Suppress a TV station logo by a simple interpolation of the surrounding
618 pixels. Just set a rectangle covering the logo and watch it disappear
619 (and sometimes something even uglier appear - your mileage may vary).
621 The filter accepts parameters as a string of the form
622 "@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
623 @var{key}=@var{value} pairs, separated by ":".
625 The description of the accepted parameters follows.
630 Specify the top left corner coordinates of the logo. They must be
634 Specify the width and height of the logo to clear. They must be
638 Specify the thickness of the fuzzy edge of the rectangle (added to
639 @var{w} and @var{h}). The default value is 4.
642 When set to 1, a green rectangle is drawn on the screen to simplify
643 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
644 @var{band} is set to 4. The default value is 0.
648 Some examples follow.
653 Set a rectangle covering the area with top left corner coordinates 0,0
654 and size 100x77, setting a band of size 10:
660 As the previous example, but use named options:
662 delogo=x=0:y=0:w=100:h=77:band=10
669 Draw a colored box on the input image.
671 It accepts the syntax:
673 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
679 Specify the top left corner coordinates of the box. Default to 0.
682 Specify the width and height of the box, if 0 they are interpreted as
683 the input width and height. Default to 0.
686 Specify the color of the box to write, it can be the name of a color
687 (case insensitive match) or a 0xRRGGBB[AA] sequence.
690 Follow some examples:
692 # draw a black box around the edge of the input image
695 # draw a box with color red and an opacity of 50%
696 drawbox=10:20:200:60:red@@0.5"
701 Draw text string or text from specified file on top of video using the
704 To enable compilation of this filter you need to configure FFmpeg with
705 @code{--enable-libfreetype}.
707 The filter also recognizes strftime() sequences in the provided text
708 and expands them accordingly. Check the documentation of strftime().
710 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
713 The description of the accepted parameters follows.
718 The font file to be used for drawing text. Path must be included.
719 This parameter is mandatory.
722 The text string to be drawn. The text must be a sequence of UTF-8
724 This parameter is mandatory if no file is specified with the parameter
728 A text file containing text to be drawn. The text must be a sequence
729 of UTF-8 encoded characters.
731 This parameter is mandatory if no text string is specified with the
732 parameter @var{text}.
734 If both text and textfile are specified, an error is thrown.
737 The expressions which specify the offsets where text will be drawn
738 within the video frame. They are relative to the top/left border of the
741 The default value of @var{x} and @var{y} is "0".
743 See below for the list of accepted constants.
746 The font size to be used for drawing text.
747 The default value of @var{fontsize} is 16.
750 The color to be used for drawing fonts.
751 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
752 (e.g. "0xff000033"), possibly followed by an alpha specifier.
753 The default value of @var{fontcolor} is "black".
756 The color to be used for drawing box around text.
757 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
758 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
759 The default value of @var{boxcolor} is "white".
762 Used to draw a box around text using background color.
763 Value should be either 1 (enable) or 0 (disable).
764 The default value of @var{box} is 0.
766 @item shadowx, shadowy
767 The x and y offsets for the text shadow position with respect to the
768 position of the text. They can be either positive or negative
769 values. Default value for both is "0".
772 The color to be used for drawing a shadow behind the drawn text. It
773 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
774 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
775 The default value of @var{shadowcolor} is "black".
778 Flags to be used for loading the fonts.
780 The flags map the corresponding flags supported by libfreetype, and are
781 a combination of the following values:
788 @item vertical_layout
792 @item ignore_global_advance_width
794 @item ignore_transform
801 Default value is "render".
803 For more information consult the documentation for the FT_LOAD_*
807 The size in number of spaces to use for rendering the tab.
811 The parameters for @var{x} and @var{y} are expressions containing the
816 the input width and heigth
819 the width of the rendered text
822 the height of the rendered text
825 the height of each text line
828 input sample aspect ratio
831 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
834 horizontal and vertical chroma subsample values. For example for the
835 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
838 maximum glyph width, that is the maximum width for all the glyphs
839 contained in the rendered text
842 maximum glyph height, that is the maximum height for all the glyphs
843 contained in the rendered text, it is equivalent to @var{ascent} -
846 @item max_glyph_a, ascent
848 the maximum distance from the baseline to the highest/upper grid
849 coordinate used to place a glyph outline point, for all the rendered
851 It is a positive value, due to the grid's orientation with the Y axis
854 @item max_glyph_d, descent
855 the maximum distance from the baseline to the lowest grid coordinate
856 used to place a glyph outline point, for all the rendered glyphs.
857 This is a negative value, due to the grid's orientation, with the Y axis
861 the number of input frame, starting from 0
864 timestamp expressed in seconds, NAN if the input timestamp is unknown
867 Some examples follow.
872 Draw "Test Text" with font FreeSerif, using the default values for the
876 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
880 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
881 and y=50 (counting from the top-left corner of the screen), text is
882 yellow with a red box around it. Both the text and the box have an
886 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
887 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
890 Note that the double quotes are not necessary if spaces are not used
891 within the parameter list.
894 Show the text at the center of the video frame:
896 drawtext=fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
900 Show a text line sliding from right to left in the last row of the video
901 frame. The file @file{LONG_LINE} is assumed to contain a single line
904 drawtext=fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t
908 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
910 drawtext=fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
914 Draw a single green letter "g", at the center of the input video.
915 The glyph baseline is placed at half screen height.
917 drawtext=fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent
922 For more information about libfreetype, check:
923 @url{http://www.freetype.org/}.
927 Apply fade-in/out effect to input video.
929 It accepts the parameters:
930 @var{type}:@var{start_frame}:@var{nb_frames}
932 @var{type} specifies if the effect type, can be either "in" for
933 fade-in, or "out" for a fade-out effect.
935 @var{start_frame} specifies the number of the start frame for starting
936 to apply the fade effect.
938 @var{nb_frames} specifies the number of frames for which the fade
939 effect has to last. At the end of the fade-in effect the output video
940 will have the same intensity as the input video, at the end of the
941 fade-out transition the output video will be completely black.
943 A few usage examples follow, usable too as test scenarios.
945 # fade in first 30 frames of video
948 # fade out last 45 frames of a 200-frame video
951 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
952 fade=in:0:25, fade=out:975:25
954 # make first 5 frames black, then fade in from frame 5-24
960 Transform the field order of the input video.
962 It accepts one parameter which specifies the required field order that
963 the input interlaced video will be transformed to. The parameter can
964 assume one of the following values:
968 output bottom field first
970 output top field first
973 Default value is "tff".
975 Transformation is achieved by shifting the picture content up or down
976 by one line, and filling the remaining line with appropriate picture content.
977 This method is consistent with most broadcast field order converters.
979 If the input video is not flagged as being interlaced, or it is already
980 flagged as being of the required output field order then this filter does
981 not alter the incoming video.
983 This filter is very useful when converting to or from PAL DV material,
984 which is bottom field first.
988 ./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
993 Buffer input images and send them when they are requested.
995 This filter is mainly useful when auto-inserted by the libavfilter
998 The filter does not take parameters.
1002 Convert the input video to one of the specified pixel formats.
1003 Libavfilter will try to pick one that is supported for the input to
1006 The filter accepts a list of pixel format names, separated by ":",
1007 for example "yuv420p:monow:rgb24".
1009 Some examples follow:
1011 # convert the input video to the format "yuv420p"
1014 # convert the input video to any of the formats in the list
1015 format=yuv420p:yuv444p:yuv410p
1021 Apply a frei0r effect to the input video.
1023 To enable compilation of this filter you need to install the frei0r
1024 header and configure FFmpeg with --enable-frei0r.
1026 The filter supports the syntax:
1028 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
1031 @var{filter_name} is the name to the frei0r effect to load. If the
1032 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
1033 is searched in each one of the directories specified by the colon
1034 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
1035 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
1036 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
1038 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
1039 for the frei0r effect.
1041 A frei0r effect parameter can be a boolean (whose values are specified
1042 with "y" and "n"), a double, a color (specified by the syntax
1043 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
1044 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
1045 description), a position (specified by the syntax @var{X}/@var{Y},
1046 @var{X} and @var{Y} being float numbers) and a string.
1048 The number and kind of parameters depend on the loaded effect. If an
1049 effect parameter is not specified the default value is set.
1051 Some examples follow:
1053 # apply the distort0r effect, set the first two double parameters
1054 frei0r=distort0r:0.5:0.01
1056 # apply the colordistance effect, takes a color as first parameter
1057 frei0r=colordistance:0.2/0.3/0.4
1058 frei0r=colordistance:violet
1059 frei0r=colordistance:0x112233
1061 # apply the perspective effect, specify the top left and top right
1063 frei0r=perspective:0.2/0.2:0.8/0.2
1066 For more information see:
1067 @url{http://piksel.org/frei0r}
1071 Fix the banding artifacts that are sometimes introduced into nearly flat
1072 regions by truncation to 8bit colordepth.
1073 Interpolate the gradients that should go where the bands are, and
1076 This filter is designed for playback only. Do not use it prior to
1077 lossy compression, because compression tends to lose the dither and
1078 bring back the bands.
1080 The filter takes two optional parameters, separated by ':':
1081 @var{strength}:@var{radius}
1083 @var{strength} is the maximum amount by which the filter will change
1084 any one pixel. Also the threshold for detecting nearly flat
1085 regions. Acceptable values range from .51 to 255, default value is
1086 1.2, out-of-range values will be clipped to the valid range.
1088 @var{radius} is the neighborhood to fit the gradient to. A larger
1089 radius makes for smoother gradients, but also prevents the filter from
1090 modifying the pixels near detailed regions. Acceptable values are
1091 8-32, default value is 16, out-of-range values will be clipped to the
1095 # default parameters
1104 Flip the input video horizontally.
1106 For example to horizontally flip the video in input with
1109 ffmpeg -i in.avi -vf "hflip" out.avi
1114 High precision/quality 3d denoise filter. This filter aims to reduce
1115 image noise producing smooth images and making still images really
1116 still. It should enhance compressibility.
1118 It accepts the following optional parameters:
1119 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
1123 a non-negative float number which specifies spatial luma strength,
1126 @item chroma_spatial
1127 a non-negative float number which specifies spatial chroma strength,
1128 defaults to 3.0*@var{luma_spatial}/4.0
1131 a float number which specifies luma temporal strength, defaults to
1132 6.0*@var{luma_spatial}/4.0
1135 a float number which specifies chroma temporal strength, defaults to
1136 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
1139 @section lut, lutrgb, lutyuv
1141 Compute a look-up table for binding each pixel component input value
1142 to an output value, and apply it to input video.
1144 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
1145 to an RGB input video.
1147 These filters accept in input a ":"-separated list of options, which
1148 specify the expressions used for computing the lookup table for the
1149 corresponding pixel component values.
1151 The @var{lut} filter requires either YUV or RGB pixel formats in
1152 input, and accepts the options:
1155 first pixel component
1157 second pixel component
1159 third pixel component
1161 fourth pixel component, corresponds to the alpha component
1164 The exact component associated to each option depends on the format in
1167 The @var{lutrgb} filter requires RGB pixel formats in input, and
1168 accepts the options:
1180 The @var{lutyuv} filter requires YUV pixel formats in input, and
1181 accepts the options:
1184 Y/luminance component
1193 The expressions can contain the following constants and functions:
1197 the input width and heigth
1200 input value for the pixel component
1203 the input value clipped in the @var{minval}-@var{maxval} range
1206 maximum value for the pixel component
1209 minimum value for the pixel component
1212 the negated value for the pixel component value clipped in the
1213 @var{minval}-@var{maxval} range , it corresponds to the expression
1214 "maxval-clipval+minval"
1217 the computed value in @var{val} clipped in the
1218 @var{minval}-@var{maxval} range
1220 @item gammaval(gamma)
1221 the computed gamma correction value of the pixel component value
1222 clipped in the @var{minval}-@var{maxval} range, corresponds to the
1224 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
1228 All expressions default to "val".
1230 Some examples follow:
1232 # negate input video
1233 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
1234 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
1236 # the above is the same as
1237 lutrgb="r=negval:g=negval:b=negval"
1238 lutyuv="y=negval:u=negval:v=negval"
1243 # remove chroma components, turns the video into a graytone image
1244 lutyuv="u=128:v=128"
1246 # apply a luma burning effect
1249 # remove green and blue components
1252 # set a constant alpha channel value on input
1253 format=rgba,lutrgb=a="maxval-minval/2"
1255 # correct luminance gamma by a 0.5 factor
1256 lutyuv=y=gammaval(0.5)
1261 Apply an MPlayer filter to the input video.
1263 This filter provides a wrapper around most of the filters of
1266 This wrapper is considered experimental. Some of the wrapped filters
1267 may not work properly and we may drop support for them, as they will
1268 be implemented natively into FFmpeg. Thus you should avoid
1269 depending on them when writing portable scripts.
1271 The filters accepts the parameters:
1272 @var{filter_name}[:=]@var{filter_params}
1274 @var{filter_name} is the name of a supported MPlayer filter,
1275 @var{filter_params} is a string containing the parameters accepted by
1278 The list of the currently supported filters follows:
1332 The parameter syntax and behavior for the listed filters are the same
1333 of the corresponding MPlayer filters. For detailed instructions check
1334 the "VIDEO FILTERS" section in the MPlayer manual.
1336 Some examples follow:
1338 # remove a logo by interpolating the surrounding pixels
1339 mp=delogo=200:200:80:20:1
1341 # adjust gamma, brightness, contrast
1344 # tweak hue and saturation
1348 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
1354 This filter accepts an integer in input, if non-zero it negates the
1355 alpha component (if available). The default value in input is 0.
1359 Force libavfilter not to use any of the specified pixel formats for the
1360 input to the next filter.
1362 The filter accepts a list of pixel format names, separated by ":",
1363 for example "yuv420p:monow:rgb24".
1365 Some examples follow:
1367 # force libavfilter to use a format different from "yuv420p" for the
1368 # input to the vflip filter
1369 noformat=yuv420p,vflip
1371 # convert the input video to any of the formats not contained in the list
1372 noformat=yuv420p:yuv444p:yuv410p
1377 Pass the video source unchanged to the output.
1381 Apply video transform using libopencv.
1383 To enable this filter install libopencv library and headers and
1384 configure FFmpeg with --enable-libopencv.
1386 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1388 @var{filter_name} is the name of the libopencv filter to apply.
1390 @var{filter_params} specifies the parameters to pass to the libopencv
1391 filter. If not specified the default values are assumed.
1393 Refer to the official libopencv documentation for more precise
1395 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1397 Follows the list of supported libopencv filters.
1402 Dilate an image by using a specific structuring element.
1403 This filter corresponds to the libopencv function @code{cvDilate}.
1405 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1407 @var{struct_el} represents a structuring element, and has the syntax:
1408 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1410 @var{cols} and @var{rows} represent the number of colums and rows of
1411 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1412 point, and @var{shape} the shape for the structuring element, and
1413 can be one of the values "rect", "cross", "ellipse", "custom".
1415 If the value for @var{shape} is "custom", it must be followed by a
1416 string of the form "=@var{filename}". The file with name
1417 @var{filename} is assumed to represent a binary image, with each
1418 printable character corresponding to a bright pixel. When a custom
1419 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1420 or columns and rows of the read file are assumed instead.
1422 The default value for @var{struct_el} is "3x3+0x0/rect".
1424 @var{nb_iterations} specifies the number of times the transform is
1425 applied to the image, and defaults to 1.
1427 Follow some example:
1429 # use the default values
1432 # dilate using a structuring element with a 5x5 cross, iterate two times
1433 ocv=dilate=5x5+2x2/cross:2
1435 # read the shape from the file diamond.shape, iterate two times
1436 # the file diamond.shape may contain a pattern of characters like this:
1442 # the specified cols and rows are ignored (but not the anchor point coordinates)
1443 ocv=0x0+2x2/custom=diamond.shape:2
1448 Erode an image by using a specific structuring element.
1449 This filter corresponds to the libopencv function @code{cvErode}.
1451 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1452 with the same syntax and semantics as the @ref{dilate} filter.
1456 Smooth the input video.
1458 The filter takes the following parameters:
1459 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1461 @var{type} is the type of smooth filter to apply, and can be one of
1462 the following values: "blur", "blur_no_scale", "median", "gaussian",
1463 "bilateral". The default value is "gaussian".
1465 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1466 parameters whose meanings depend on smooth type. @var{param1} and
1467 @var{param2} accept integer positive values or 0, @var{param3} and
1468 @var{param4} accept float values.
1470 The default value for @var{param1} is 3, the default value for the
1471 other parameters is 0.
1473 These parameters correspond to the parameters assigned to the
1474 libopencv function @code{cvSmooth}.
1478 Overlay one video on top of another.
1480 It takes two inputs and one output, the first input is the "main"
1481 video on which the second input is overlayed.
1483 It accepts the parameters: @var{x}:@var{y}.
1485 @var{x} is the x coordinate of the overlayed video on the main video,
1486 @var{y} is the y coordinate. The parameters are expressions containing
1487 the following parameters:
1490 @item main_w, main_h
1491 main input width and height
1494 same as @var{main_w} and @var{main_h}
1496 @item overlay_w, overlay_h
1497 overlay input width and height
1500 same as @var{overlay_w} and @var{overlay_h}
1503 Be aware that frames are taken from each input video in timestamp
1504 order, hence, if their initial timestamps differ, it is a a good idea
1505 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1506 have them begin in the same zero timestamp, as it does the example for
1507 the @var{movie} filter.
1509 Follow some examples:
1511 # draw the overlay at 10 pixels from the bottom right
1512 # corner of the main video.
1513 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1515 # insert a transparent PNG logo in the bottom left corner of the input
1516 movie=logo.png [logo];
1517 [in][logo] overlay=10:main_h-overlay_h-10 [out]
1519 # insert 2 different transparent PNG logos (second logo on bottom
1521 movie=logo1.png [logo1];
1522 movie=logo2.png [logo2];
1523 [in][logo1] overlay=10:H-h-10 [in+logo1];
1524 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
1526 # add a transparent color layer on top of the main video,
1527 # WxH specifies the size of the main input to the overlay filter
1528 color=red@.3:WxH [over]; [in][over] overlay [out]
1531 You can chain togheter more overlays but the efficiency of such
1532 approach is yet to be tested.
1536 Add paddings to the input image, and places the original input at the
1537 given coordinates @var{x}, @var{y}.
1539 It accepts the following parameters:
1540 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1542 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1543 expressions containing the following constants:
1547 the input video width and height
1550 same as @var{in_w} and @var{in_h}
1553 the output width and height, that is the size of the padded area as
1554 specified by the @var{width} and @var{height} expressions
1557 same as @var{out_w} and @var{out_h}
1560 x and y offsets as specified by the @var{x} and @var{y}
1561 expressions, or NAN if not yet specified
1564 same as @var{iw} / @var{ih}
1567 input sample aspect ratio
1570 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1573 horizontal and vertical chroma subsample values. For example for the
1574 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1577 Follows the description of the accepted parameters.
1582 Specify the size of the output image with the paddings added. If the
1583 value for @var{width} or @var{height} is 0, the corresponding input size
1584 is used for the output.
1586 The @var{width} expression can reference the value set by the
1587 @var{height} expression, and viceversa.
1589 The default value of @var{width} and @var{height} is 0.
1593 Specify the offsets where to place the input image in the padded area
1594 with respect to the top/left border of the output image.
1596 The @var{x} expression can reference the value set by the @var{y}
1597 expression, and viceversa.
1599 The default value of @var{x} and @var{y} is 0.
1603 Specify the color of the padded area, it can be the name of a color
1604 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1606 The default value of @var{color} is "black".
1610 Some examples follow:
1613 # Add paddings with color "violet" to the input video. Output video
1614 # size is 640x480, the top-left corner of the input video is placed at
1616 pad=640:480:0:40:violet
1618 # pad the input to get an output with dimensions increased bt 3/2,
1619 # and put the input video at the center of the padded area
1620 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1622 # pad the input to get a squared output with size equal to the maximum
1623 # value between the input width and height, and put the input video at
1624 # the center of the padded area
1625 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1627 # pad the input to get a final w/h ratio of 16:9
1628 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1630 # for anamorphic video, in order to set the output display aspect ratio,
1631 # it is necessary to use sar in the expression, according to the relation:
1632 # (ih * X / ih) * sar = output_dar
1633 # X = output_dar / sar
1634 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
1636 # double output size and put the input video in the bottom-right
1637 # corner of the output padded area
1638 pad="2*iw:2*ih:ow-iw:oh-ih"
1641 @section pixdesctest
1643 Pixel format descriptor test filter, mainly useful for internal
1644 testing. The output video should be equal to the input video.
1648 format=monow, pixdesctest
1651 can be used to test the monowhite pixel format descriptor definition.
1655 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1657 The parameters @var{width} and @var{height} are expressions containing
1658 the following constants:
1662 the input width and height
1665 same as @var{in_w} and @var{in_h}
1668 the output (cropped) width and height
1671 same as @var{out_w} and @var{out_h}
1674 same as @var{iw} / @var{ih}
1677 input sample aspect ratio
1680 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
1683 input sample aspect ratio
1686 horizontal and vertical chroma subsample values. For example for the
1687 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1690 If the input image format is different from the format requested by
1691 the next filter, the scale filter will convert the input to the
1694 If the value for @var{width} or @var{height} is 0, the respective input
1695 size is used for the output.
1697 If the value for @var{width} or @var{height} is -1, the scale filter will
1698 use, for the respective output size, a value that maintains the aspect
1699 ratio of the input image.
1701 The default value of @var{width} and @var{height} is 0.
1703 Some examples follow:
1705 # scale the input video to a size of 200x100.
1708 # scale the input to 2x
1710 # the above is the same as
1713 # scale the input to half size
1716 # increase the width, and set the height to the same size
1719 # seek for Greek harmony
1723 # increase the height, and set the width to 3/2 of the height
1726 # increase the size, but make the size a multiple of the chroma
1727 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1729 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1730 scale='min(500\, iw*3/2):-1'
1734 Select frames to pass in output.
1736 It accepts in input an expression, which is evaluated for each input
1737 frame. If the expression is evaluated to a non-zero value, the frame
1738 is selected and passed to the output, otherwise it is discarded.
1740 The expression can contain the following constants:
1744 the sequential number of the filtered frame, starting from 0
1747 the sequential number of the selected frame, starting from 0
1749 @item prev_selected_n
1750 the sequential number of the last selected frame, NAN if undefined
1753 timebase of the input timestamps
1756 the PTS (Presentation TimeStamp) of the filtered video frame,
1757 expressed in @var{TB} units, NAN if undefined
1760 the PTS (Presentation TimeStamp) of the filtered video frame,
1761 expressed in seconds, NAN if undefined
1764 the PTS of the previously filtered video frame, NAN if undefined
1766 @item prev_selected_pts
1767 the PTS of the last previously filtered video frame, NAN if undefined
1769 @item prev_selected_t
1770 the PTS of the last previously selected video frame, NAN if undefined
1773 the PTS of the first video frame in the video, NAN if undefined
1776 the time of the first video frame in the video, NAN if undefined
1779 the type of the filtered frame, can assume one of the following
1791 @item interlace_type
1792 the frame interlace type, can assume one of the following values:
1795 the frame is progressive (not interlaced)
1797 the frame is top-field-first
1799 the frame is bottom-field-first
1803 1 if the filtered frame is a key-frame, 0 otherwise
1806 the position in the file of the filtered frame, -1 if the information
1807 is not available (e.g. for synthetic video)
1810 The default value of the select expression is "1".
1812 Some examples follow:
1815 # select all frames in input
1818 # the above is the same as:
1824 # select only I-frames
1825 select='eq(pict_type\,I)'
1827 # select one frame every 100
1828 select='not(mod(n\,100))'
1830 # select only frames contained in the 10-20 time interval
1831 select='gte(t\,10)*lte(t\,20)'
1833 # select only I frames contained in the 10-20 time interval
1834 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1836 # select frames with a minimum distance of 10 seconds
1837 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1843 Set the Display Aspect Ratio for the filter output video.
1845 This is done by changing the specified Sample (aka Pixel) Aspect
1846 Ratio, according to the following equation:
1847 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1849 Keep in mind that this filter does not modify the pixel dimensions of
1850 the video frame. Also the display aspect ratio set by this filter may
1851 be changed by later filters in the filterchain, e.g. in case of
1852 scaling or if another "setdar" or a "setsar" filter is applied.
1854 The filter accepts a parameter string which represents the wanted
1855 display aspect ratio.
1856 The parameter can be a floating point number string, or an expression
1857 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1858 numerator and denominator of the aspect ratio.
1859 If the parameter is not specified, it is assumed the value "0:1".
1861 For example to change the display aspect ratio to 16:9, specify:
1864 # the above is equivalent to
1868 See also the @ref{setsar} filter documentation.
1872 Change the PTS (presentation timestamp) of the input video frames.
1874 Accept in input an expression evaluated through the eval API, which
1875 can contain the following constants:
1879 the presentation timestamp in input
1882 the count of the input frame, starting from 0.
1885 the PTS of the first video frame
1888 tell if the current frame is interlaced
1891 original position in the file of the frame, or undefined if undefined
1892 for the current frame
1902 Some examples follow:
1905 # start counting PTS from zero
1917 # fixed rate 25 fps with some jitter
1918 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1924 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1926 Note that as a consequence of the application of this filter, the
1927 output display aspect ratio will change according to the following
1929 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1931 Keep in mind that the sample aspect ratio set by this filter may be
1932 changed by later filters in the filterchain, e.g. if another "setsar"
1933 or a "setdar" filter is applied.
1935 The filter accepts a parameter string which represents the wanted
1936 sample aspect ratio.
1937 The parameter can be a floating point number string, or an expression
1938 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1939 numerator and denominator of the aspect ratio.
1940 If the parameter is not specified, it is assumed the value "0:1".
1942 For example to change the sample aspect ratio to 10:11, specify:
1949 Set the timebase to use for the output frames timestamps.
1950 It is mainly useful for testing timebase configuration.
1952 It accepts in input an arithmetic expression representing a rational.
1953 The expression can contain the constants "AVTB" (the
1954 default timebase), and "intb" (the input timebase).
1956 The default value for the input is "intb".
1958 Follow some examples.
1961 # set the timebase to 1/25
1964 # set the timebase to 1/10
1967 #set the timebase to 1001/1000
1970 #set the timebase to 2*intb
1973 #set the default timebase value
1979 Show a line containing various information for each input video frame.
1980 The input video is not modified.
1982 The shown line contains a sequence of key/value pairs of the form
1983 @var{key}:@var{value}.
1985 A description of each shown parameter follows:
1989 sequential number of the input frame, starting from 0
1992 Presentation TimeStamp of the input frame, expressed as a number of
1993 time base units. The time base unit depends on the filter input pad.
1996 Presentation TimeStamp of the input frame, expressed as a number of
2000 position of the frame in the input stream, -1 if this information in
2001 unavailable and/or meanigless (for example in case of synthetic video)
2007 sample aspect ratio of the input frame, expressed in the form
2011 size of the input frame, expressed in the form
2012 @var{width}x@var{height}
2015 interlaced mode ("P" for "progressive", "T" for top field first, "B"
2016 for bottom field first)
2019 1 if the frame is a key frame, 0 otherwise
2022 picture type of the input frame ("I" for an I-frame, "P" for a
2023 P-frame, "B" for a B-frame, "?" for unknown type).
2024 Check also the documentation of the @code{AVPictureType} enum and of
2025 the @code{av_get_picture_type_char} function defined in
2026 @file{libavutil/avutil.h}.
2029 Adler-32 checksum of all the planes of the input frame
2031 @item plane_checksum
2032 Adler-32 checksum of each plane of the input frame, expressed in the form
2033 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
2038 Pass the images of input video on to next video filter as multiple
2042 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
2045 The filter accepts the slice height as parameter. If the parameter is
2046 not specified it will use the default value of 16.
2048 Adding this in the beginning of filter chains should make filtering
2049 faster due to better use of the memory cache.
2053 Pass on the input video to two outputs. Both outputs are identical to
2058 [in] split [splitout1][splitout2];
2059 [splitout1] crop=100:100:0:0 [cropout];
2060 [splitout2] pad=200:200:100:100 [padout];
2063 will create two separate outputs from the same input, one cropped and
2068 Transpose rows with columns in the input video and optionally flip it.
2070 It accepts a parameter representing an integer, which can assume the
2075 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
2083 Rotate by 90 degrees clockwise, that is:
2091 Rotate by 90 degrees counterclockwise, that is:
2099 Rotate by 90 degrees clockwise and vertically flip, that is:
2109 Sharpen or blur the input video.
2111 It accepts the following parameters:
2112 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
2114 Negative values for the amount will blur the input video, while positive
2115 values will sharpen. All parameters are optional and default to the
2116 equivalent of the string '5:5:1.0:5:5:0.0'.
2121 Set the luma matrix horizontal size. It can be an integer between 3
2122 and 13, default value is 5.
2125 Set the luma matrix vertical size. It can be an integer between 3
2126 and 13, default value is 5.
2129 Set the luma effect strength. It can be a float number between -2.0
2130 and 5.0, default value is 1.0.
2132 @item chroma_msize_x
2133 Set the chroma matrix horizontal size. It can be an integer between 3
2134 and 13, default value is 5.
2136 @item chroma_msize_y
2137 Set the chroma matrix vertical size. It can be an integer between 3
2138 and 13, default value is 5.
2141 Set the chroma effect strength. It can be a float number between -2.0
2142 and 5.0, default value is 0.0.
2147 # Strong luma sharpen effect parameters
2150 # Strong blur of both luma and chroma parameters
2151 unsharp=7:7:-2:7:7:-2
2153 # Use the default values with @command{ffmpeg}
2154 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
2159 Flip the input video vertically.
2162 ./ffmpeg -i in.avi -vf "vflip" out.avi
2167 Deinterlace the input video ("yadif" means "yet another deinterlacing
2170 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
2172 @var{mode} specifies the interlacing mode to adopt, accepts one of the
2177 output 1 frame for each frame
2179 output 1 frame for each field
2181 like 0 but skips spatial interlacing check
2183 like 1 but skips spatial interlacing check
2188 @var{parity} specifies the picture field parity assumed for the input
2189 interlaced video, accepts one of the following values:
2193 assume top field first
2195 assume bottom field first
2197 enable automatic detection
2200 Default value is -1.
2201 If interlacing is unknown or decoder does not export this information,
2202 top field first will be assumed.
2204 @var{auto} specifies if deinterlacer should trust the interlaced flag
2205 and only deinterlace frames marked as interlaced
2209 deinterlace all frames
2211 only deinterlace frames marked as interlaced
2216 @c man end VIDEO FILTERS
2218 @chapter Video Sources
2219 @c man begin VIDEO SOURCES
2221 Below is a description of the currently available video sources.
2225 Buffer video frames, and make them available to the filter chain.
2227 This source is mainly intended for a programmatic use, in particular
2228 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
2230 It accepts the following parameters:
2231 @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}
2233 All the parameters but @var{scale_params} need to be explicitely
2236 Follows the list of the accepted parameters.
2241 Specify the width and height of the buffered video frames.
2243 @item pix_fmt_string
2244 A string representing the pixel format of the buffered video frames.
2245 It may be a number corresponding to a pixel format, or a pixel format
2248 @item timebase_num, timebase_den
2249 Specify numerator and denomitor of the timebase assumed by the
2250 timestamps of the buffered frames.
2252 @item sample_aspect_ratio.num, sample_aspect_ratio.den
2253 Specify numerator and denominator of the sample aspect ratio assumed
2254 by the video frames.
2257 Specify the optional parameters to be used for the scale filter which
2258 is automatically inserted when an input change is detected in the
2259 input size or format.
2264 buffer=320:240:yuv410p:1:24:1:1
2267 will instruct the source to accept video frames with size 320x240 and
2268 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2269 square pixels (1:1 sample aspect ratio).
2270 Since the pixel format with name "yuv410p" corresponds to the number 6
2271 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
2272 this example corresponds to:
2274 buffer=320:240:6:1:24:1:1
2279 Provide an uniformly colored input.
2281 It accepts the following parameters:
2282 @var{color}:@var{frame_size}:@var{frame_rate}
2284 Follows the description of the accepted parameters.
2289 Specify the color of the source. It can be the name of a color (case
2290 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2291 alpha specifier. The default value is "black".
2294 Specify the size of the sourced video, it may be a string of the form
2295 @var{width}x@var{height}, or the name of a size abbreviation. The
2296 default value is "320x240".
2299 Specify the frame rate of the sourced video, as the number of frames
2300 generated per second. It has to be a string in the format
2301 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2302 number or a valid video frame rate abbreviation. The default value is
2307 For example the following graph description will generate a red source
2308 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2309 frames per second, which will be overlayed over the source connected
2310 to the pad with identifier "in".
2313 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2318 Read a video stream from a movie container.
2320 It accepts the syntax: @var{movie_name}[:@var{options}] where
2321 @var{movie_name} is the name of the resource to read (not necessarily
2322 a file but also a device or a stream accessed through some protocol),
2323 and @var{options} is an optional sequence of @var{key}=@var{value}
2324 pairs, separated by ":".
2326 The description of the accepted options follows.
2330 @item format_name, f
2331 Specifies the format assumed for the movie to read, and can be either
2332 the name of a container or an input device. If not specified the
2333 format is guessed from @var{movie_name} or by probing.
2335 @item seek_point, sp
2336 Specifies the seek point in seconds, the frames will be output
2337 starting from this seek point, the parameter is evaluated with
2338 @code{av_strtod} so the numerical value may be suffixed by an IS
2339 postfix. Default value is "0".
2341 @item stream_index, si
2342 Specifies the index of the video stream to read. If the value is -1,
2343 the best suited video stream will be automatically selected. Default
2348 This filter allows to overlay a second video on top of main input of
2349 a filtergraph as shown in this graph:
2351 input -----------> deltapts0 --> overlay --> output
2354 movie --> scale--> deltapts1 -------+
2357 Some examples follow:
2359 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2360 # on top of the input labelled as "in".
2361 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2362 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2364 # read from a video4linux2 device, and overlay it on top of the input
2366 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2367 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2373 Generate various test patterns, as generated by the MPlayer test filter.
2375 The size of the generated video is fixed, and is 256x256.
2376 This source is useful in particular for testing encoding features.
2378 This source accepts an optional sequence of @var{key}=@var{value} pairs,
2379 separated by ":". The description of the accepted options follows.
2384 Specify the frame rate of the sourced video, as the number of frames
2385 generated per second. It has to be a string in the format
2386 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2387 number or a valid video frame rate abbreviation. The default value is
2391 Set the video duration of the sourced video. The accepted syntax is:
2393 [-]HH[:MM[:SS[.m...]]]
2396 See also the function @code{av_parse_time()}.
2398 If not specified, or the expressed duration is negative, the video is
2399 supposed to be generated forever.
2403 Set the number or the name of the test to perform. Supported tests are:
2418 Default value is "all", which will cycle through the list of all tests.
2421 For example the following:
2426 will generate a "dc_luma" test pattern.
2430 Null video source, never return images. It is mainly useful as a
2431 template and to be employed in analysis / debugging tools.
2433 It accepts as optional parameter a string of the form
2434 @var{width}:@var{height}:@var{timebase}.
2436 @var{width} and @var{height} specify the size of the configured
2437 source. The default values of @var{width} and @var{height} are
2438 respectively 352 and 288 (corresponding to the CIF size format).
2440 @var{timebase} specifies an arithmetic expression representing a
2441 timebase. The expression can contain the constant
2442 "AVTB" (the default timebase), and defaults to the value "AVTB".
2446 Provide a frei0r source.
2448 To enable compilation of this filter you need to install the frei0r
2449 header and configure FFmpeg with --enable-frei0r.
2451 The source supports the syntax:
2453 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2456 @var{size} is the size of the video to generate, may be a string of the
2457 form @var{width}x@var{height} or a frame size abbreviation.
2458 @var{rate} is the rate of the video to generate, may be a string of
2459 the form @var{num}/@var{den} or a frame rate abbreviation.
2460 @var{src_name} is the name to the frei0r source to load. For more
2461 information regarding frei0r and how to set the parameters read the
2462 section @ref{frei0r} in the description of the video filters.
2464 Some examples follow:
2466 # generate a frei0r partik0l source with size 200x200 and framerate 10
2467 # which is overlayed on the overlay filter main input
2468 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2471 @section rgbtestsrc, testsrc
2473 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2474 detecting RGB vs BGR issues. You should see a red, green and blue
2475 stripe from top to bottom.
2477 The @code{testsrc} source generates a test video pattern, showing a
2478 color pattern, a scrolling gradient and a timestamp. This is mainly
2479 intended for testing purposes.
2481 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2482 separated by ":". The description of the accepted options follows.
2487 Specify the size of the sourced video, it may be a string of the form
2488 @var{width}x@var{heigth}, or the name of a size abbreviation. The
2489 default value is "320x240".
2492 Specify the frame rate of the sourced video, as the number of frames
2493 generated per second. It has to be a string in the format
2494 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2495 number or a valid video frame rate abbreviation. The default value is
2499 Set the sample aspect ratio of the sourced video.
2502 Set the video duration of the sourced video. The accepted syntax is:
2504 [-]HH[:MM[:SS[.m...]]]
2507 See also the function @code{av_parse_time()}.
2509 If not specified, or the expressed duration is negative, the video is
2510 supposed to be generated forever.
2513 For example the following:
2515 testsrc=duration=5.3:size=qcif:rate=10
2518 will generate a video with a duration of 5.3 seconds, with size
2519 176x144 and a framerate of 10 frames per second.
2521 @c man end VIDEO SOURCES
2523 @chapter Video Sinks
2524 @c man begin VIDEO SINKS
2526 Below is a description of the currently available video sinks.
2530 Buffer video frames, and make them available to the end of the filter
2533 This sink is mainly intended for a programmatic use, in particular
2534 through the interface defined in @file{libavfilter/buffersink.h}.
2536 It does not require a string parameter in input, but you need to
2537 specify a pointer to a list of supported pixel formats terminated by
2538 -1 in the opaque parameter provided to @code{avfilter_init_filter}
2539 when initializing this sink.
2543 Null video sink, do absolutely nothing with the input video. It is
2544 mainly useful as a template and to be employed in analysis / debugging
2547 @c man end VIDEO SINKS