1 @chapter Filtergraph description
2 @c man begin FILTERGRAPH DESCRIPTION
4 A filtergraph is a directed graph of connected filters. It can contain
5 cycles, and there can be multiple links between a pair of
6 filters. Each link has one input pad on one side connecting it to one
7 filter from which it takes its input, and one output pad on the other
8 side connecting it to the one filter accepting its output.
10 Each filter in a filtergraph is an instance of a filter class
11 registered in the application, which defines the features and the
12 number of input and output pads of the filter.
14 A filter with no input pads is called a "source", a filter with no
15 output pads is called a "sink".
17 @section Filtergraph syntax
19 A filtergraph can be represented using a textual representation, which
20 is recognized by the @code{-vf} and @code{-af} options of the ff*
21 tools, and by the @code{av_parse_graph()} function defined in
22 @file{libavfilter/avfiltergraph}.
24 A filterchain consists of a sequence of connected filters, each one
25 connected to the previous one in the sequence. A filterchain is
26 represented by a list of ","-separated filter descriptions.
28 A filtergraph consists of a sequence of filterchains. A sequence of
29 filterchains is represented by a list of ";"-separated filterchain
32 A filter is represented by a string of the form:
33 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
35 @var{filter_name} is the name of the filter class of which the
36 described filter is an instance of, and has to be the name of one of
37 the filter classes registered in the program.
38 The name of the filter class is optionally followed by a string
41 @var{arguments} is a string which contains the parameters used to
42 initialize the filter instance, and are described in the filter
45 The list of arguments can be quoted using the character "'" as initial
46 and ending mark, and the character '\' for escaping the characters
47 within the quoted text; otherwise the argument string is considered
48 terminated when the next special character (belonging to the set
49 "[]=;,") is encountered.
51 The name and arguments of the filter are optionally preceded and
52 followed by a list of link labels.
53 A link label allows to name a link and associate it to a filter output
54 or input pad. The preceding labels @var{in_link_1}
55 ... @var{in_link_N}, are associated to the filter input pads,
56 the following labels @var{out_link_1} ... @var{out_link_M}, are
57 associated to the output pads.
59 When two link labels with the same name are found in the
60 filtergraph, a link between the corresponding input and output pad is
63 If an output pad is not labelled, it is linked by default to the first
64 unlabelled input pad of the next filter in the filterchain.
65 For example in the filterchain:
67 nullsrc, split[L1], [L2]overlay, nullsink
69 the split filter instance has two output pads, and the overlay filter
70 instance two input pads. The first output pad of split is labelled
71 "L1", the first input pad of overlay is labelled "L2", and the second
72 output pad of split is linked to the second input pad of overlay,
73 which are both unlabelled.
75 In a complete filterchain all the unlabelled filter input and output
76 pads must be connected. A filtergraph is considered valid if all the
77 filter input and output pads of all the filterchains are connected.
79 Follows a BNF description for the filtergraph syntax:
81 @var{NAME} ::= sequence of alphanumeric characters and '_'
82 @var{LINKLABEL} ::= "[" @var{NAME} "]"
83 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
84 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
85 @var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
86 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
87 @var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
90 @c man end FILTERGRAPH DESCRIPTION
92 @chapter Audio Filters
93 @c man begin AUDIO FILTERS
95 When you configure your FFmpeg build, you can disable any of the
96 existing filters using --disable-filters.
97 The configure output will show the audio filters included in your
100 Below is a description of the currently available audio filters.
104 Pass the audio source unchanged to the output.
106 @c man end AUDIO FILTERS
108 @chapter Audio Sources
109 @c man begin AUDIO SOURCES
111 Below is a description of the currently available audio sources.
115 Null audio source, never return audio frames. It is mainly useful as a
116 template and to be employed in analysis / debugging tools.
118 It accepts as optional parameter a string of the form
119 @var{sample_rate}:@var{channel_layout}.
121 @var{sample_rate} specify the sample rate, and defaults to 44100.
123 @var{channel_layout} specify the channel layout, and can be either an
124 integer or a string representing a channel layout. The default value
125 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
127 Check the channel_layout_map definition in
128 @file{libavcodec/audioconvert.c} for the mapping between strings and
129 channel layout values.
131 Follow some examples:
133 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
140 @c man end AUDIO SOURCES
143 @c man begin AUDIO SINKS
145 Below is a description of the currently available audio sinks.
149 Null audio sink, do absolutely nothing with the input audio. It is
150 mainly useful as a template and to be employed in analysis / debugging
153 @c man end AUDIO SINKS
155 @chapter Video Filters
156 @c man begin VIDEO FILTERS
158 When you configure your FFmpeg build, you can disable any of the
159 existing filters using --disable-filters.
160 The configure output will show the video filters included in your
163 Below is a description of the currently available video filters.
167 Detect frames that are (almost) completely black. Can be useful to
168 detect chapter transitions or commercials. Output lines consist of
169 the frame number of the detected frame, the percentage of blackness,
170 the position in the file if known or -1 and the timestamp in seconds.
172 In order to display the output lines, you need to set the loglevel at
173 least to the AV_LOG_INFO value.
175 The filter accepts the syntax:
177 blackframe[=@var{amount}:[@var{threshold}]]
180 @var{amount} is the percentage of the pixels that have to be below the
181 threshold, and defaults to 98.
183 @var{threshold} is the threshold below which a pixel value is
184 considered black, and defaults to 32.
188 Copy the input source unchanged to the output. Mainly useful for
193 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
195 The parameters are expressions containing the following constants:
199 the corresponding mathematical approximated values for e
200 (euler number), pi (greek PI), PHI (golden ratio)
203 the computed values for @var{x} and @var{y}. They are evaluated for
207 the input width and heigth
210 same as @var{in_w} and @var{in_h}
213 the output (cropped) width and heigth
216 same as @var{out_w} and @var{out_h}
219 the number of input frame, starting from 0
222 the position in the file of the input frame, NAN if unknown
225 timestamp expressed in seconds, NAN if the input timestamp is unknown
229 The @var{out_w} and @var{out_h} parameters specify the expressions for
230 the width and height of the output (cropped) video. They are
231 evaluated just at the configuration of the filter.
233 The default value of @var{out_w} is "in_w", and the default value of
234 @var{out_h} is "in_h".
236 The expression for @var{out_w} may depend on the value of @var{out_h},
237 and the expression for @var{out_h} may depend on @var{out_w}, but they
238 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
239 evaluated after @var{out_w} and @var{out_h}.
241 The @var{x} and @var{y} parameters specify the expressions for the
242 position of the top-left corner of the output (non-cropped) area. They
243 are evaluated for each frame. If the evaluated value is not valid, it
244 is approximated to the nearest valid value.
246 The default value of @var{x} is "(in_w-out_w)/2", and the default
247 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
248 the center of the input image.
250 The expression for @var{x} may depend on @var{y}, and the expression
251 for @var{y} may depend on @var{x}.
253 Follow some examples:
255 # crop the central input area with size 100x100
258 # crop the central input area with size 2/3 of the input video
259 "crop=2/3*in_w:2/3*in_h"
261 # crop the input video central square
264 # delimit the rectangle with the top-left corner placed at position
265 # 100:100 and the right-bottom corner corresponding to the right-bottom
266 # corner of the input image.
267 crop=in_w-100:in_h-100:100:100
269 # crop 10 pixels from the left and right borders, and 20 pixels from
270 # the top and bottom borders
271 "crop=in_w-2*10:in_h-2*20"
273 # keep only the bottom right quarter of the input image
274 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
276 # crop height for getting Greek harmony
277 "crop=in_w:1/PHI*in_w"
280 "crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
282 # erratic camera effect depending on timestamp
283 "crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
285 # set x depending on the value of y
286 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
291 Auto-detect crop size.
293 Calculate necessary cropping parameters and prints the recommended
294 parameters through the logging system. The detected dimensions
295 correspond to the non-black area of the input video.
297 It accepts the syntax:
299 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
305 Threshold, which can be optionally specified from nothing (0) to
306 everything (255), defaults to 24.
309 Value which the width/height should be divisible by, defaults to
310 16. The offset is automatically adjusted to center the video. Use 2 to
311 get only even dimensions (needed for 4:2:2 video). 16 is best when
312 encoding to most video codecs.
315 Counter that determines after how many frames cropdetect will reset
316 the previously detected largest video area and start over to detect
317 the current optimal crop area. Defaults to 0.
319 This can be useful when channel logos distort the video area. 0
320 indicates never reset and return the largest area encountered during
326 Draw a colored box on the input image.
328 It accepts the syntax:
330 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
336 Specify the top left corner coordinates of the box. Default to 0.
339 Specify the width and height of the box, if 0 they are interpreted as
340 the input width and height. Default to 0.
343 Specify the color of the box to write, it can be the name of a color
344 (case insensitive match) or a 0xRRGGBB[AA] sequence.
347 Follow some examples:
349 # draw a black box around the edge of the input image
352 # draw a box with color red and an opacity of 50%
353 drawbox=10:20:200:60:red@@0.5"
358 Buffer input images and send them when they are requested.
360 This filter is mainly useful when auto-inserted by the libavfilter
363 The filter does not take parameters.
367 Convert the input video to one of the specified pixel formats.
368 Libavfilter will try to pick one that is supported for the input to
371 The filter accepts a list of pixel format names, separated by ":",
372 for example "yuv420p:monow:rgb24".
374 Some examples follow:
376 # convert the input video to the format "yuv420p"
379 # convert the input video to any of the formats in the list
380 format=yuv420p:yuv444p:yuv410p
386 Apply a frei0r effect to the input video.
388 To enable compilation of this filter you need to install the frei0r
389 header and configure FFmpeg with --enable-frei0r.
391 The filter supports the syntax:
393 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
396 @var{filter_name} is the name to the frei0r effect to load. If the
397 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
398 is searched in each one of the directories specified by the colon
399 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
400 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
401 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
403 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
404 for the frei0r effect.
406 A frei0r effect parameter can be a boolean (whose values are specified
407 with "y" and "n"), a double, a color (specified by the syntax
408 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
409 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
410 description), a position (specified by the syntax @var{X}/@var{Y},
411 @var{X} and @var{Y} being float numbers) and a string.
413 The number and kind of parameters depend on the loaded effect. If an
414 effect parameter is not specified the default value is set.
416 Some examples follow:
418 # apply the distort0r effect, set the first two double parameters
419 frei0r=distort0r:0.5:0.01
421 # apply the colordistance effect, takes a color as first parameter
422 frei0r=colordistance:0.2/0.3/0.4
423 frei0r=colordistance:violet
424 frei0r=colordistance:0x112233
426 # apply the perspective effect, specify the top left and top right
428 frei0r=perspective:0.2/0.2:0.8/0.2
431 For more information see:
432 @url{http://piksel.org/frei0r}
436 Fix the banding artifacts that are sometimes introduced into nearly flat
437 regions by truncation to 8bit colordepth.
438 Interpolate the gradients that should go where the bands are, and
441 The filter takes two optional parameters, separated by ':':
442 @var{strength}:@var{radius}
444 @var{strength} is the maximum amount by which the filter will change
445 any one pixel. Also the threshold for detecting nearly flat
446 regions. Acceptable values range from .51 to 255, default value is
447 1.2, out-of-range values will be clipped to the valid range.
449 @var{radius} is the neighborhood to fit the gradient to. A larger
450 radius makes for smoother gradients, but also prevents the filter from
451 modifying the pixels near detailed regions. Acceptable values are
452 8-32, default value is 16, out-of-range values will be clipped to the
465 Flip the input video horizontally.
467 For example to horizontally flip the video in input with
470 ffmpeg -i in.avi -vf "hflip" out.avi
475 High precision/quality 3d denoise filter. This filter aims to reduce
476 image noise producing smooth images and making still images really
477 still. It should enhance compressibility.
479 It accepts the following optional parameters:
480 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
484 a non-negative float number which specifies spatial luma strength,
488 a non-negative float number which specifies spatial chroma strength,
489 defaults to 3.0*@var{luma_spatial}/4.0
492 a float number which specifies luma temporal strength, defaults to
493 6.0*@var{luma_spatial}/4.0
496 a float number which specifies chroma temporal strength, defaults to
497 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
502 Force libavfilter not to use any of the specified pixel formats for the
503 input to the next filter.
505 The filter accepts a list of pixel format names, separated by ":",
506 for example "yuv420p:monow:rgb24".
508 Some examples follow:
510 # force libavfilter to use a format different from "yuv420p" for the
511 # input to the vflip filter
512 noformat=yuv420p,vflip
514 # convert the input video to any of the formats not contained in the list
515 noformat=yuv420p:yuv444p:yuv410p
520 Pass the video source unchanged to the output.
524 Apply video transform using libopencv.
526 To enable this filter install libopencv library and headers and
527 configure FFmpeg with --enable-libopencv.
529 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
531 @var{filter_name} is the name of the libopencv filter to apply.
533 @var{filter_params} specifies the parameters to pass to the libopencv
534 filter. If not specified the default values are assumed.
536 Refer to the official libopencv documentation for more precise
538 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
540 Follows the list of supported libopencv filters.
545 Dilate an image by using a specific structuring element.
546 This filter corresponds to the libopencv function @code{cvDilate}.
548 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
550 @var{struct_el} represents a structuring element, and has the syntax:
551 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
553 @var{cols} and @var{rows} represent the number of colums and rows of
554 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
555 point, and @var{shape} the shape for the structuring element, and
556 can be one of the values "rect", "cross", "ellipse", "custom".
558 If the value for @var{shape} is "custom", it must be followed by a
559 string of the form "=@var{filename}". The file with name
560 @var{filename} is assumed to represent a binary image, with each
561 printable character corresponding to a bright pixel. When a custom
562 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
563 or columns and rows of the read file are assumed instead.
565 The default value for @var{struct_el} is "3x3+0x0/rect".
567 @var{nb_iterations} specifies the number of times the transform is
568 applied to the image, and defaults to 1.
572 # use the default values
575 # dilate using a structuring element with a 5x5 cross, iterate two times
576 ocv=dilate=5x5+2x2/cross:2
578 # read the shape from the file diamond.shape, iterate two times
579 # the file diamond.shape may contain a pattern of characters like this:
585 # the specified cols and rows are ignored (but not the anchor point coordinates)
586 ocv=0x0+2x2/custom=diamond.shape:2
591 Erode an image by using a specific structuring element.
592 This filter corresponds to the libopencv function @code{cvErode}.
594 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
595 with the same meaning and use of those of the dilate filter
600 Smooth the input video.
602 The filter takes the following parameters:
603 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
605 @var{type} is the type of smooth filter to apply, and can be one of
606 the following values: "blur", "blur_no_scale", "median", "gaussian",
607 "bilateral". The default value is "gaussian".
609 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
610 parameters whose meanings depend on smooth type. @var{param1} and
611 @var{param2} accept integer positive values or 0, @var{param3} and
612 @var{param4} accept float values.
614 The default value for @var{param1} is 3, the default value for the
615 other parameters is 0.
617 These parameters correspond to the parameters assigned to the
618 libopencv function @code{cvSmooth}.
622 Overlay one video on top of another.
624 It takes two inputs and one output, the first input is the "main"
625 video on which the second input is overlayed.
627 It accepts the parameters: @var{x}:@var{y}.
629 @var{x} is the x coordinate of the overlayed video on the main video,
630 @var{y} is the y coordinate. The parameters are expressions containing
631 the following parameters:
635 main input width and height
638 same as @var{main_w} and @var{main_h}
640 @item overlay_w, overlay_h
641 overlay input width and height
644 same as @var{overlay_w} and @var{overlay_h}
647 Be aware that frames are taken from each input video in timestamp
648 order, hence, if their initial timestamps differ, it is a a good idea
649 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
650 have them begin in the same zero timestamp, as it does the example for
651 the @var{movie} filter.
653 Follow some examples:
655 # draw the overlay at 10 pixels from the bottom right
656 # corner of the main video.
657 overlay=main_w-overlay_w-10:main_h-overlay_h-10
659 # insert a transparent PNG logo in the bottom left corner of the input
660 movie=0:png:logo.png [logo];
661 [in][logo] overlay=10:main_h-overlay_h-10 [out]
663 # insert 2 different transparent PNG logos (second logo on bottom
665 movie=0:png:logo1.png [logo1];
666 movie=0:png:logo2.png [logo2];
667 [in][logo1] overlay=10:H-h-10 [in+logo1];
668 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
670 # add a transparent color layer on top of the main video,
671 # WxH specifies the size of the main input to the overlay filter
672 color=red@.3:WxH [over]; [in][over] overlay [out]
675 You can chain togheter more overlays but the efficiency of such
676 approach is yet to be tested.
680 Add paddings to the input image, and places the original input at the
681 given coordinates @var{x}, @var{y}.
683 It accepts the following parameters:
684 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
686 Follows the description of the accepted parameters.
691 Specify the size of the output image with the paddings added. If the
692 value for @var{width} or @var{height} is 0, the corresponding input size
693 is used for the output.
695 The default value of @var{width} and @var{height} is 0.
699 Specify the offsets where to place the input image in the padded area
700 with respect to the top/left border of the output image.
702 The default value of @var{x} and @var{y} is 0.
706 Specify the color of the padded area, it can be the name of a color
707 (case insensitive match) or a 0xRRGGBB[AA] sequence.
709 The default value of @var{color} is "black".
716 # Add paddings with color "violet" to the input video. Output video
717 # size is 640x480, the top-left corner of the input video is placed at
719 pad=640:480:0:40:violet
724 Pixel format descriptor test filter, mainly useful for internal
725 testing. The output video should be equal to the input video.
729 format=monow, pixdesctest
732 can be used to test the monowhite pixel format descriptor definition.
736 Scale the input video to @var{width}:@var{height} and/or convert the image format.
738 For example the command:
741 ./ffmpeg -i in.avi -vf "scale=200:100" out.avi
744 will scale the input video to a size of 200x100.
746 If the input image format is different from the format requested by
747 the next filter, the scale filter will convert the input to the
750 If the value for @var{width} or @var{height} is 0, the respective input
751 size is used for the output.
753 If the value for @var{width} or @var{height} is -1, the scale filter will
754 use, for the respective output size, a value that maintains the aspect
755 ratio of the input image.
757 The default value of @var{width} and @var{height} is 0.
761 Change the PTS (presentation timestamp) of the input video frames.
763 Accept in input an expression evaluated through the eval API, which
764 can contain the following constants:
768 the presentation timestamp in input
780 the count of the input frame, starting from 0.
783 the PTS of the first video frame
786 tell if the current frame is interlaced
789 original position in the file of the frame, or undefined if undefined
790 for the current frame
800 Some examples follow:
803 # start counting PTS from zero
815 # fixed rate 25 fps with some jitter
816 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
821 Set the timebase to use for the output frames timestamps.
822 It is mainly useful for testing timebase configuration.
824 It accepts in input an arithmetic expression representing a rational.
825 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
826 default timebase), and "intb" (the input timebase).
828 The default value for the input is "intb".
830 Follow some examples.
833 # set the timebase to 1/25
836 # set the timebase to 1/10
839 #set the timebase to 1001/1000
842 #set the timebase to 2*intb
845 #set the default timebase value
851 Pass the images of input video on to next video filter as multiple
855 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
858 The filter accepts the slice height as parameter. If the parameter is
859 not specified it will use the default value of 16.
861 Adding this in the beginning of filter chains should make filtering
862 faster due to better use of the memory cache.
866 Transpose rows with columns in the input video and optionally flip it.
868 It accepts a parameter representing an integer, which can assume the
873 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
881 Rotate by 90 degrees clockwise, that is:
889 Rotate by 90 degrees counterclockwise, that is:
897 Rotate by 90 degrees clockwise and vertically flip, that is:
907 Sharpen or blur the input video.
909 It accepts the following parameters:
910 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
912 Negative values for the amount will blur the input video, while positive
913 values will sharpen. All parameters are optional and default to the
914 equivalent of the string '5:5:1.0:0:0:0.0'.
919 Set the luma matrix horizontal size. It can be an integer between 3
920 and 13, default value is 5.
923 Set the luma matrix vertical size. It can be an integer between 3
924 and 13, default value is 5.
927 Set the luma effect strength. It can be a float number between -2.0
928 and 5.0, default value is 1.0.
931 Set the chroma matrix horizontal size. It can be an integer between 3
932 and 13, default value is 0.
935 Set the chroma matrix vertical size. It can be an integer between 3
936 and 13, default value is 0.
939 Set the chroma effect strength. It can be a float number between -2.0
940 and 5.0, default value is 0.0.
945 # Strong luma sharpen effect parameters
948 # Strong blur of both luma and chroma parameters
949 unsharp=7:7:-2:7:7:-2
951 # Use the default values with @command{ffmpeg}
952 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
957 Flip the input video vertically.
960 ./ffmpeg -i in.avi -vf "vflip" out.avi
965 Deinterlace the input video ("yadif" means "yet another deinterlacing
968 It accepts the optional parameters: @var{mode}:@var{parity}.
970 @var{mode} specifies the interlacing mode to adopt, accepts one of the
975 output 1 frame for each frame
977 output 1 frame for each field
979 like 0 but skips spatial interlacing check
981 like 1 but skips spatial interlacing check
986 @var{parity} specifies the picture field parity assumed for the input
987 interlaced video, accepts one of the following values:
991 assume bottom field first
993 assume top field first
995 enable automatic detection
999 If interlacing is unknown or decoder does not export this information,
1000 top field first will be assumed.
1002 @c man end VIDEO FILTERS
1004 @chapter Video Sources
1005 @c man begin VIDEO SOURCES
1007 Below is a description of the currently available video sources.
1011 Buffer video frames, and make them available to the filter chain.
1013 This source is mainly intended for a programmatic use, in particular
1014 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1016 It accepts the following parameters:
1017 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}
1019 All the parameters need to be explicitely defined.
1021 Follows the list of the accepted parameters.
1026 Specify the width and height of the buffered video frames.
1028 @item pix_fmt_string
1029 A string representing the pixel format of the buffered video frames.
1030 It may be a number corresponding to a pixel format, or a pixel format
1033 @item timebase_num, timebase_den
1034 Specify numerator and denomitor of the timebase assumed by the
1035 timestamps of the buffered frames.
1040 buffer=320:240:yuv410p:1:24
1043 will instruct the source to accept video frames with size 320x240 and
1044 with format "yuv410p" and assuming 1/24 as the timestamps timebase.
1045 Since the pixel format with name "yuv410p" corresponds to the number 6
1046 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1047 this example corresponds to:
1049 buffer=320:240:6:1:24
1054 Provide an uniformly colored input.
1056 It accepts the following parameters:
1057 @var{color}:@var{frame_size}:@var{frame_rate}
1059 Follows the description of the accepted parameters.
1064 Specify the color of the source. It can be the name of a color (case
1065 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1066 alpha specifier. The default value is "black".
1069 Specify the size of the sourced video, it may be a string of the form
1070 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1071 default value is "320x240".
1074 Specify the frame rate of the sourced video, as the number of frames
1075 generated per second. It has to be a string in the format
1076 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1077 number or a valid video frame rate abbreviation. The default value is
1082 For example the following graph description will generate a red source
1083 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1084 frames per second, which will be overlayed over the source connected
1085 to the pad with identifier "in".
1088 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1093 Read a video stream from a movie container.
1095 It accepts the syntax: @var{movie_name}[:@var{options}] where
1096 @var{movie_name} is the name of the resource to read (not necessarily
1097 a file but also a device or a stream accessed through some protocol),
1098 and @var{options} is an optional sequence of @var{key}=@var{value}
1099 pairs, separated by ":".
1101 The description of the accepted options follows.
1105 @item format_name, f
1106 Specifies the format assumed for the movie to read, and can be either
1107 the name of a container or an input device. If not specified the
1108 format is guessed from @var{movie_name} or by probing.
1110 @item seek_point, sp
1111 Specifies the seek point in seconds, the frames will be output
1112 starting from this seek point, the parameter is evaluated with
1113 @code{av_strtod} so the numerical value may be suffixed by an IS
1114 postfix. Default value is "0".
1116 @item stream_index, si
1117 Specifies the index of the video stream to read. If the value is -1,
1118 the best suited video stream will be automatically selected. Default
1123 This filter allows to overlay a second video on top of main input of
1124 a filtergraph as shown in this graph:
1126 input -----------> deltapts0 --> overlay --> output
1129 movie --> scale--> deltapts1 -------+
1132 Some examples follow:
1134 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1135 # on top of the input labelled as "in".
1136 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1137 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1139 # read from a video4linux2 device, and overlay it on top of the input
1141 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1142 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1148 Null video source, never return images. It is mainly useful as a
1149 template and to be employed in analysis / debugging tools.
1151 It accepts as optional parameter a string of the form
1152 @var{width}:@var{height}:@var{timebase}.
1154 @var{width} and @var{height} specify the size of the configured
1155 source. The default values of @var{width} and @var{height} are
1156 respectively 352 and 288 (corresponding to the CIF size format).
1158 @var{timebase} specifies an arithmetic expression representing a
1159 timebase. The expression can contain the constants "PI", "E", "PHI",
1160 "AVTB" (the default timebase), and defaults to the value "AVTB".
1164 Provide a frei0r source.
1166 To enable compilation of this filter you need to install the frei0r
1167 header and configure FFmpeg with --enable-frei0r.
1169 The source supports the syntax:
1171 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1174 @var{size} is the size of the video to generate, may be a string of the
1175 form @var{width}x@var{height} or a frame size abbreviation.
1176 @var{rate} is the rate of the video to generate, may be a string of
1177 the form @var{num}/@var{den} or a frame rate abbreviation.
1178 @var{src_name} is the name to the frei0r source to load. For more
1179 information regarding frei0r and how to set the parameters read the
1180 section "frei0r" (@pxref{frei0r}) in the description of the video
1183 Some examples follow:
1185 # generate a frei0r partik0l source with size 200x200 and framerate 10
1186 # which is overlayed on the overlay filter main input
1187 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1190 @c man end VIDEO SOURCES
1192 @chapter Video Sinks
1193 @c man begin VIDEO SINKS
1195 Below is a description of the currently available video sinks.
1199 Null video sink, do absolutely nothing with the input video. It is
1200 mainly useful as a template and to be employed in analysis / debugging
1203 @c man end VIDEO SINKS