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 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
190 The parameters are expressions containing the following constants:
194 the corresponding mathematical approximated values for e
195 (euler number), pi (greek PI), PHI (golden ratio)
198 the computed values for @var{x} and @var{y}. They are evaluated for
202 the input width and heigth
205 same as @var{in_w} and @var{in_h}
208 the output (cropped) width and heigth
211 same as @var{out_w} and @var{out_h}
214 the number of input frame, starting from 0
217 the position in the file of the input frame, NAN if unknown
220 timestamp expressed in seconds, NAN if the input timestamp is unknown
224 The @var{out_w} and @var{out_h} parameters specify the expressions for
225 the width and height of the output (cropped) video. They are
226 evaluated just at the configuration of the filter.
228 The default value of @var{out_w} is "in_w", and the default value of
229 @var{out_h} is "in_h".
231 The expression for @var{out_w} may depend on the value of @var{out_h},
232 and the expression for @var{out_h} may depend on @var{out_w}, but they
233 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
234 evaluated after @var{out_w} and @var{out_h}.
236 The @var{x} and @var{y} parameters specify the expressions for the
237 position of the top-left corner of the output (non-cropped) area. They
238 are evaluated for each frame. If the evaluated value is not valid, it
239 is approximated to the nearest valid value.
241 The default value of @var{x} is "(in_w-out_w)/2", and the default
242 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
243 the center of the input image.
245 The expression for @var{x} may depend on @var{y}, and the expression
246 for @var{y} may depend on @var{x}.
248 Follow some examples:
250 # crop the central input area with size 100x100
253 # crop the central input area with size 2/3 of the input video
254 "crop=2/3*in_w:2/3*in_h"
256 # crop the input video central square
259 # delimit the rectangle with the top-left corner placed at position
260 # 100:100 and the right-bottom corner corresponding to the right-bottom
261 # corner of the input image.
262 crop=in_w-100:in_h-100:100:100
264 # crop 10 pixels from the lefth and right borders, and 20 pixels from
265 # the top and bottom borders
266 "crop=in_w-2*10:in_h-2*20"
268 # keep only the bottom right quarter of the input image
269 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
271 # crop height for getting Greek harmony
272 "crop=in_w:1/PHI*in_w"
275 "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)"
277 # erratic camera effect depending on timestamp and position
278 "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)"
280 # set x depending on the value of y
281 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
286 Auto-detect crop size.
288 Calculate necessary cropping parameters and prints the recommended
289 parameters through the logging system. The detected dimensions
290 correspond to the non-black area of the input video.
292 It accepts the syntax:
294 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
300 Threshold, which can be optionally specified from nothing (0) to
301 everything (255), defaults to 24.
304 Value which the width/height should be divisible by, defaults to
305 16. The offset is automatically adjusted to center the video. Use 2 to
306 get only even dimensions (needed for 4:2:2 video). 16 is best when
307 encoding to most video codecs.
310 Counter that determines after how many frames cropdetect will reset
311 the previously detected largest video area and start over to detect
312 the current optimal crop area. Defaults to 0.
314 This can be useful when channel logos distort the video area. 0
315 indicates never reset and return the largest area encountered during
321 Draw a colored box on the input image.
323 It accepts the syntax:
325 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
331 Specify the top left corner coordinates of the box. Default to 0.
334 Specify the width and height of the box, if 0 they are interpreted as
335 the input width and height. Default to 0.
338 Specify the color of the box to write, it can be the name of a color
339 (case insensitive match) or a 0xRRGGBB[AA] sequence.
342 Follow some examples:
344 # draw a black box around the edge of the input image
347 # draw a box with color red and an opacity of 50%
348 drawbox=10:20:200:60:red@@0.5"
353 Buffer input images and send them when they are requested.
355 This filter is mainly useful when auto-inserted by the libavfilter
358 The filter does not take parameters.
362 Convert the input video to one of the specified pixel formats.
363 Libavfilter will try to pick one that is supported for the input to
366 The filter accepts a list of pixel format names, separated by ":",
367 for example "yuv420p:monow:rgb24".
369 The following command:
372 ./ffmpeg -i in.avi -vf "format=yuv420p" out.avi
375 will convert the input video to the format "yuv420p".
380 Apply a frei0r effect to the input video.
382 To enable compilation of this filter you need to install the frei0r
383 header and configure FFmpeg with --enable-frei0r.
385 The filter supports the syntax:
387 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
390 @var{filter_name} is the name to the frei0r effect to load. If the
391 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
392 is searched in each one of the directories specified by the colon
393 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
394 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
395 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
397 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
398 for the frei0r effect.
400 A frei0r effect parameter can be a boolean (whose values are specified
401 with "y" and "n"), a double, a color (specified by the syntax
402 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
403 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
404 description), a position (specified by the syntax @var{X}/@var{Y},
405 @var{X} and @var{Y} being float numbers) and a string.
407 The number and kind of parameters depend on the loaded effect. If an
408 effect parameter is not specified the default value is set.
410 Some examples follow:
412 # apply the distort0r effect, set the first two double parameters
413 frei0r=distort0r:0.5:0.01
415 # apply the colordistance effect, takes a color as first parameter
416 frei0r=colordistance:0.2/0.3/0.4
417 frei0r=colordistance:violet
418 frei0r=colordistance:0x112233
420 # apply the perspective effect, specify the top left and top right
422 frei0r=perspective:0.2/0.2:0.8/0.2
425 For more information see:
426 @url{http://piksel.org/frei0r}
430 Fix the banding artifacts that are sometimes introduced into nearly flat
431 regions by truncation to 8bit colordepth.
432 Interpolate the gradients that should go where the bands are, and
435 The filter takes two optional parameters, separated by ':':
436 @var{strength}:@var{radius}
438 @var{strength} is the maximum amount by which the filter will change
439 any one pixel. Also the threshold for detecting nearly flat
440 regions. Acceptable values range from .51 to 255, default value is
441 1.2, out-of-range values will be clipped to the valid range.
443 @var{radius} is the neighborhood to fit the gradient to. A larger
444 radius makes for smoother gradients, but also prevents the filter from
445 modifying the pixels near detailed regions. Acceptable values are
446 8-32, default value is 16, out-of-range values will be clipped to the
459 Flip the input video horizontally.
461 For example to horizontally flip the video in input with
464 ffmpeg -i in.avi -vf "hflip" out.avi
469 High precision/quality 3d denoise filter. This filter aims to reduce
470 image noise producing smooth images and making still images really
471 still. It should enhance compressibility.
473 It accepts the following optional parameters:
474 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
478 a non-negative float number which specifies spatial luma strength,
482 a non-negative float number which specifies spatial chroma strength,
483 defaults to 3.0*@var{luma_spatial}/4.0
486 a float number which specifies luma temporal strength, defaults to
487 6.0*@var{luma_spatial}/4.0
490 a float number which specifies chroma temporal strength, defaults to
491 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
496 Force libavfilter not to use any of the specified pixel formats for the
497 input to the next filter.
499 The filter accepts a list of pixel format names, separated by ":",
500 for example "yuv420p:monow:rgb24".
502 The following command:
505 ./ffmpeg -i in.avi -vf "noformat=yuv420p, vflip" out.avi
508 will make libavfilter use a format different from "yuv420p" for the
509 input to the vflip filter.
513 Pass the video source unchanged to the output.
517 Apply video transform using libopencv.
519 To enable this filter install libopencv library and headers and
520 configure FFmpeg with --enable-libopencv.
522 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
524 @var{filter_name} is the name of the libopencv filter to apply.
526 @var{filter_params} specifies the parameters to pass to the libopencv
527 filter. If not specified the default values are assumed.
529 Refer to the official libopencv documentation for more precise
531 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
533 Follows the list of supported libopencv filters.
537 Smooth the input video.
539 The filter takes the following parameters:
540 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
542 @var{type} is the type of smooth filter to apply, and can be one of
543 the following values: "blur", "blur_no_scale", "median", "gaussian",
544 "bilateral". The default value is "gaussian".
546 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
547 parameters whose meanings depend on smooth type. @var{param1} and
548 @var{param2} accept integer positive values or 0, @var{param3} and
549 @var{param4} accept float values.
551 The default value for @var{param1} is 3, the default value for the
552 other parameters is 0.
554 These parameters correspond to the parameters assigned to the
555 libopencv function @code{cvSmooth}.
559 Overlay one video on top of another.
561 It takes two inputs and one output, the first input is the "main"
562 video on which the second input is overlayed.
564 It accepts the parameters: @var{x}:@var{y}.
566 @var{x} is the x coordinate of the overlayed video on the main video,
567 @var{y} is the y coordinate. The parameters are expressions containing
568 the following parameters:
572 main input width and height
575 same as @var{main_w} and @var{main_h}
577 @item overlay_w, overlay_h
578 overlay input width and height
581 same as @var{overlay_w} and @var{overlay_h}
584 Be aware that frames are taken from each input video in timestamp
585 order, hence, if their initial timestamps differ, it is a a good idea
586 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
587 have them begin in the same zero timestamp, as it does the example for
588 the @var{movie} filter.
590 Follow some examples:
592 # draw the overlay at 10 pixels from the bottom right
593 # corner of the main video.
594 overlay=main_w-overlay_w-10:main_h-overlay_h-10
596 # insert a transparent PNG logo in the bottom left corner of the input
597 movie=0:png:logo.png [logo];
598 [in][logo] overlay=10:main_h-overlay_h-10 [out]
600 # insert 2 different transparent PNG logos (second logo on bottom
602 movie=0:png:logo1.png [logo1];
603 movie=0:png:logo2.png [logo2];
604 [in][logo1] overlay=10:H-h-10 [in+logo1];
605 [in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
607 # add a transparent color layer on top of the main video,
608 # WxH specifies the size of the main input to the overlay filter
609 color=red@.3:WxH [over]; [in][over] overlay [out]
612 You can chain togheter more overlays but the efficiency of such
613 approach is yet to be tested.
617 Add paddings to the input image, and places the original input at the
618 given coordinates @var{x}, @var{y}.
620 It accepts the following parameters:
621 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
623 Follows the description of the accepted parameters.
628 Specify the size of the output image with the paddings added. If the
629 value for @var{width} or @var{height} is 0, the corresponding input size
630 is used for the output.
632 The default value of @var{width} and @var{height} is 0.
636 Specify the offsets where to place the input image in the padded area
637 with respect to the top/left border of the output image.
639 The default value of @var{x} and @var{y} is 0.
643 Specify the color of the padded area, it can be the name of a color
644 (case insensitive match) or a 0xRRGGBB[AA] sequence.
646 The default value of @var{color} is "black".
653 # Add paddings with color "violet" to the input video. Output video
654 # size is 640x480, the top-left corner of the input video is placed at
656 pad=640:480:0:40:violet
661 Pixel format descriptor test filter, mainly useful for internal
662 testing. The output video should be equal to the input video.
666 format=monow, pixdesctest
669 can be used to test the monowhite pixel format descriptor definition.
673 Scale the input video to @var{width}:@var{height} and/or convert the image format.
675 For example the command:
678 ./ffmpeg -i in.avi -vf "scale=200:100" out.avi
681 will scale the input video to a size of 200x100.
683 If the input image format is different from the format requested by
684 the next filter, the scale filter will convert the input to the
687 If the value for @var{width} or @var{height} is 0, the respective input
688 size is used for the output.
690 If the value for @var{width} or @var{height} is -1, the scale filter will
691 use, for the respective output size, a value that maintains the aspect
692 ratio of the input image.
694 The default value of @var{width} and @var{height} is 0.
698 Change the PTS (presentation timestamp) of the input video frames.
700 Accept in input an expression evaluated through the eval API, which
701 can contain the following constants:
705 the presentation timestamp in input
717 the count of the input frame, starting from 0.
720 the PTS of the first video frame
723 tell if the current frame is interlaced
726 original position in the file of the frame, or undefined if undefined
727 for the current frame
737 Some examples follow:
740 # start counting PTS from zero
752 # fixed rate 25 fps with some jitter
753 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
758 Set the timebase to use for the output frames timestamps.
759 It is mainly useful for testing timebase configuration.
761 It accepts in input an arithmetic expression representing a rational.
762 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
763 default timebase), and "intb" (the input timebase).
765 The default value for the input is "intb".
767 Follow some examples.
770 # set the timebase to 1/25
773 # set the timebase to 1/10
776 #set the timebase to 1001/1000
779 #set the timebase to 2*intb
782 #set the default timebase value
788 Pass the images of input video on to next video filter as multiple
792 ./ffmpeg -i in.avi -vf "slicify=32" out.avi
795 The filter accepts the slice height as parameter. If the parameter is
796 not specified it will use the default value of 16.
798 Adding this in the beginning of filter chains should make filtering
799 faster due to better use of the memory cache.
803 Transpose rows with columns in the input video and optionally flip it.
805 It accepts a parameter representing an integer, which can assume the
810 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
818 Rotate by 90 degrees clockwise, that is:
826 Rotate by 90 degrees counterclockwise, that is:
834 Rotate by 90 degrees clockwise and vertically flip, that is:
844 Sharpen or blur the input video.
846 It accepts the following parameters:
847 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
849 Negative values for the amount will blur the input video, while positive
850 values will sharpen. All parameters are optional and default to the
851 equivalent of the string '5:5:1.0:0:0:0.0'.
856 Set the luma matrix horizontal size. It can be an integer between 3
857 and 13, default value is 5.
860 Set the luma matrix vertical size. It can be an integer between 3
861 and 13, default value is 5.
864 Set the luma effect strength. It can be a float number between -2.0
865 and 5.0, default value is 1.0.
868 Set the chroma matrix horizontal size. It can be an integer between 3
869 and 13, default value is 0.
872 Set the chroma matrix vertical size. It can be an integer between 3
873 and 13, default value is 0.
876 Set the chroma effect strength. It can be a float number between -2.0
877 and 5.0, default value is 0.0.
882 # Strong luma sharpen effect parameters
885 # Strong blur of both luma and chroma parameters
886 unsharp=7:7:-2:7:7:-2
888 # Use the default values with @command{ffmpeg}
889 ./ffmpeg -i in.avi -vf "unsharp" out.mp4
894 Flip the input video vertically.
897 ./ffmpeg -i in.avi -vf "vflip" out.avi
902 Deinterlace the input video ("yadif" means "yet another deinterlacing
905 It accepts the optional parameters: @var{mode}:@var{parity}.
907 @var{mode} specifies the interlacing mode to adopt, accepts one of the
912 output 1 frame for each frame
914 output 1 frame for each field
916 like 0 but skips spatial interlacing check
918 like 1 but skips spatial interlacing check
923 @var{parity} specifies the picture field parity assumed for the input
924 interlaced video, accepts one of the following values:
928 assume bottom field first
930 assume top field first
932 enable automatic detection
937 @c man end VIDEO FILTERS
939 @chapter Video Sources
940 @c man begin VIDEO SOURCES
942 Below is a description of the currently available video sources.
946 Buffer video frames, and make them available to the filter chain.
948 This source is mainly intended for a programmatic use, in particular
949 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
951 It accepts the following parameters:
952 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}
954 All the parameters need to be explicitely defined.
956 Follows the list of the accepted parameters.
961 Specify the width and height of the buffered video frames.
964 A string representing the pixel format of the buffered video frames.
965 It may be a number corresponding to a pixel format, or a pixel format
968 @item timebase_num, timebase_den
969 Specify numerator and denomitor of the timebase assumed by the
970 timestamps of the buffered frames.
975 buffer=320:240:yuv410p:1:24
978 will instruct the source to accept video frames with size 320x240 and
979 with format "yuv410p" and assuming 1/24 as the timestamps timebase.
980 Since the pixel format with name "yuv410p" corresponds to the number 6
981 (check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
982 this example corresponds to:
984 buffer=320:240:6:1:24
989 Provide an uniformly colored input.
991 It accepts the following parameters:
992 @var{color}:@var{frame_size}:@var{frame_rate}
994 Follows the description of the accepted parameters.
999 Specify the color of the source. It can be the name of a color (case
1000 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1001 alpha specifier. The default value is "black".
1004 Specify the size of the sourced video, it may be a string of the form
1005 @var{width}x@var{heigth}, or the name of a size abbreviation. The
1006 default value is "320x240".
1009 Specify the frame rate of the sourced video, as the number of frames
1010 generated per second. It has to be a string in the format
1011 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1012 number or a valid video frame rate abbreviation. The default value is
1017 For example the following graph description will generate a red source
1018 with an opacity of 0.2, with size "qcif" and a frame rate of 10
1019 frames per second, which will be overlayed over the source connected
1020 to the pad with identifier "in".
1023 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1028 Null video source, never return images. It is mainly useful as a
1029 template and to be employed in analysis / debugging tools.
1031 It accepts as optional parameter a string of the form
1032 @var{width}:@var{height}:@var{timebase}.
1034 @var{width} and @var{height} specify the size of the configured
1035 source. The default values of @var{width} and @var{height} are
1036 respectively 352 and 288 (corresponding to the CIF size format).
1038 @var{timebase} specifies an arithmetic expression representing a
1039 timebase. The expression can contain the constants "PI", "E", "PHI",
1040 "AVTB" (the default timebase), and defaults to the value "AVTB".
1044 Provide a frei0r source.
1046 To enable compilation of this filter you need to install the frei0r
1047 header and configure FFmpeg with --enable-frei0r.
1049 The source supports the syntax:
1051 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1054 @var{size} is the size of the video to generate, may be a string of the
1055 form @var{width}x@var{height} or a frame size abbreviation.
1056 @var{rate} is the rate of the video to generate, may be a string of
1057 the form @var{num}/@var{den} or a frame rate abbreviation.
1058 @var{src_name} is the name to the frei0r source to load. For more
1059 information regarding frei0r and how to set the parameters read the
1060 section "frei0r" (@pxref{frei0r}) in the description of the video
1063 Some examples follow:
1065 # generate a frei0r partik0l source with size 200x200 and framerate 10
1066 # which is overlayed on the overlay filter main input
1067 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1070 @c man end VIDEO SOURCES
1072 @chapter Video Sinks
1073 @c man begin VIDEO SINKS
1075 Below is a description of the currently available video sinks.
1079 Null video sink, do absolutely nothing with the input video. It is
1080 mainly useful as a template and to be employed in analysis / debugging
1083 @c man end VIDEO SINKS