Statistics
| Branch: | Revision:

ffmpeg / doc / filters.texi @ 7dd29fb6

History | View | Annotate | Download (43.3 KB)

1
@chapter Filtergraph description
2
@c man begin FILTERGRAPH DESCRIPTION
3

    
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.
9

    
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.
13

    
14
A filter with no input pads is called a "source", a filter with no
15
output pads is called a "sink".
16

    
17
@section Filtergraph syntax
18

    
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}.
23

    
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.
27

    
28
A filtergraph consists of a sequence of filterchains. A sequence of
29
filterchains is represented by a list of ";"-separated filterchain
30
descriptions.
31

    
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}]
34

    
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
39
"=@var{arguments}".
40

    
41
@var{arguments} is a string which contains the parameters used to
42
initialize the filter instance, and are described in the filter
43
descriptions below.
44

    
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.
50

    
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.
58

    
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
61
created.
62

    
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:
66
@example
67
nullsrc, split[L1], [L2]overlay, nullsink
68
@end example
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.
74

    
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.
78

    
79
Follows a BNF description for the filtergraph syntax:
80
@example
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}]
88
@end example
89

    
90
@c man end FILTERGRAPH DESCRIPTION
91

    
92
@chapter Audio Filters
93
@c man begin AUDIO FILTERS
94

    
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
98
build.
99

    
100
Below is a description of the currently available audio filters.
101

    
102
@section anull
103

    
104
Pass the audio source unchanged to the output.
105

    
106
@c man end AUDIO FILTERS
107

    
108
@chapter Audio Sources
109
@c man begin AUDIO SOURCES
110

    
111
Below is a description of the currently available audio sources.
112

    
113
@section anullsrc
114

    
115
Null audio source, never return audio frames. It is mainly useful as a
116
template and to be employed in analysis / debugging tools.
117

    
118
It accepts as optional parameter a string of the form
119
@var{sample_rate}:@var{channel_layout}.
120

    
121
@var{sample_rate} specify the sample rate, and defaults to 44100.
122

    
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.
126

    
127
Check the channel_layout_map definition in
128
@file{libavcodec/audioconvert.c} for the mapping between strings and
129
channel layout values.
130

    
131
Follow some examples:
132
@example
133
#  set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
134
anullsrc=48000:4
135

    
136
# same as
137
anullsrc=48000:mono
138
@end example
139

    
140
@c man end AUDIO SOURCES
141

    
142
@chapter Audio Sinks
143
@c man begin AUDIO SINKS
144

    
145
Below is a description of the currently available audio sinks.
146

    
147
@section anullsink
148

    
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
151
tools.
152

    
153
@c man end AUDIO SINKS
154

    
155
@chapter Video Filters
156
@c man begin VIDEO FILTERS
157

    
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
161
build.
162

    
163
Below is a description of the currently available video filters.
164

    
165
@section blackframe
166

    
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.
171

    
172
In order to display the output lines, you need to set the loglevel at
173
least to the AV_LOG_INFO value.
174

    
175
The filter accepts the syntax:
176
@example
177
blackframe[=@var{amount}:[@var{threshold}]]
178
@end example
179

    
180
@var{amount} is the percentage of the pixels that have to be below the
181
threshold, and defaults to 98.
182

    
183
@var{threshold} is the threshold below which a pixel value is
184
considered black, and defaults to 32.
185

    
186
@section copy
187

    
188
Copy the input source unchanged to the output. Mainly useful for
189
testing purposes.
190

    
191
@section crop
192

    
193
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
194

    
195
The parameters are expressions containing the following constants:
196

    
197
@table @option
198
@item E, PI, PHI
199
the corresponding mathematical approximated values for e
200
(euler number), pi (greek PI), PHI (golden ratio)
201

    
202
@item x, y
203
the computed values for @var{x} and @var{y}. They are evaluated for
204
each new frame.
205

    
206
@item in_w, in_h
207
the input width and heigth
208

    
209
@item iw, ih
210
same as @var{in_w} and @var{in_h}
211

    
212
@item out_w, out_h
213
the output (cropped) width and heigth
214

    
215
@item ow, oh
216
same as @var{out_w} and @var{out_h}
217

    
218
@item n
219
the number of input frame, starting from 0
220

    
221
@item pos
222
the position in the file of the input frame, NAN if unknown
223

    
224
@item t
225
timestamp expressed in seconds, NAN if the input timestamp is unknown
226

    
227
@end table
228

    
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.
232

    
233
The default value of @var{out_w} is "in_w", and the default value of
234
@var{out_h} is "in_h".
235

    
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}.
240

    
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.
245

    
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.
249

    
250
The expression for @var{x} may depend on @var{y}, and the expression
251
for @var{y} may depend on @var{x}.
252

    
253
Follow some examples:
254
@example
255
# crop the central input area with size 100x100
256
crop=100:100
257

    
258
# crop the central input area with size 2/3 of the input video
259
"crop=2/3*in_w:2/3*in_h"
260

    
261
# crop the input video central square
262
crop=in_h
263

    
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
268

    
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"
272

    
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"
275

    
276
# crop height for getting Greek harmony
277
"crop=in_w:1/PHI*in_w"
278

    
279
# trembling effect
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)"
281

    
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)"
284

    
285
# set x depending on the value of y
286
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
287
@end example
288

    
289
@section cropdetect
290

    
291
Auto-detect crop size.
292

    
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.
296

    
297
It accepts the syntax:
298
@example
299
cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
300
@end example
301

    
302
@table @option
303

    
304
@item limit
305
Threshold, which can be optionally specified from nothing (0) to
306
everything (255), defaults to 24.
307

    
308
@item round
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.
313

    
314
@item reset
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.
318

    
319
This can be useful when channel logos distort the video area. 0
320
indicates never reset and return the largest area encountered during
321
playback.
322
@end table
323

    
324
@section drawbox
325

    
326
Draw a colored box on the input image.
327

    
328
It accepts the syntax:
329
@example
330
drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
331
@end example
332

    
333
@table @option
334

    
335
@item x, y
336
Specify the top left corner coordinates of the box. Default to 0.
337

    
338
@item width, height
339
Specify the width and height of the box, if 0 they are interpreted as
340
the input width and height. Default to 0.
341

    
342
@item color
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.
345
@end table
346

    
347
Follow some examples:
348
@example
349
# draw a black box around the edge of the input image
350
drawbox
351

    
352
# draw a box with color red and an opacity of 50%
353
drawbox=10:20:200:60:red@@0.5"
354
@end example
355

    
356
@section drawtext
357

    
358
Draw text string or text from specified file on top of video using the
359
libfreetype library.
360

    
361
To enable compilation of this filter you need to configure FFmpeg with
362
@code{--enable-libfreetype}.
363

    
364
The filter also recognizes strftime() sequences in the provided text
365
and expands them accordingly. Check the documentation of strftime().
366

    
367
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
368
separated by ":".
369

    
370
The description of the accepted parameters follows.
371

    
372
@table @option
373

    
374
@item fontfile
375
The font file to be used for drawing text. Path must be included.
376
This parameter is mandatory.
377

    
378
@item text
379
The text string to be drawn. The text must be a sequence of UTF-8
380
encoded characters.
381
This parameter is mandatory if no file is specified with the parameter
382
@var{textfile}.
383

    
384
@item textfile
385
A text file containing text to be drawn. The text must be a sequence
386
of UTF-8 encoded characters.
387

    
388
This parameter is mandatory if no text string is specified with the
389
parameter @var{text}.
390

    
391
If both text and textfile are specified, an error is thrown.
392

    
393
@item x, y
394
The offsets where text will be drawn within the video frame.
395
Relative to the top/left border of the output image.
396

    
397
The default value of @var{x} and @var{y} is 0.
398

    
399
@item fontsize
400
The font size to be used for drawing text.
401
The default value of @var{fontsize} is 16.
402

    
403
@item fontcolor
404
The color to be used for drawing fonts.
405
Either a string (e.g. "red") or in 0xRRGGBB[AA] format
406
(e.g. "0xff000033"), possibly followed by an alpha specifier.
407
The default value of @var{fontcolor} is "black".
408

    
409
@item boxcolor
410
The color to be used for drawing box around text.
411
Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
412
(e.g. "0xff00ff"), possibly followed by an alpha specifier.
413
The default value of @var{boxcolor} is "white".
414

    
415
@item box
416
Used to draw a box around text using background color.
417
Value should be either 1 (enable) or 0 (disable).
418
The default value of @var{box} is 0.
419

    
420
@item shadowx, shadowy
421
The x and y offsets for the text shadow position with respect to the
422
position of the text. They can be either positive or negative
423
values. Default value for both is "0".
424

    
425
@item shadowcolor
426
The color to be used for drawing a shadow behind the drawn text.  It
427
can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
428
form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
429
The default value of @var{shadowcolor} is "black".
430

    
431
@item ft_load_flags
432
Flags to be used for loading the fonts.
433

    
434
The flags map the corresponding flags supported by libfreetype, and are
435
a combination of the following values:
436
@table @var
437
@item default
438
@item no_scale
439
@item no_hinting
440
@item render
441
@item no_bitmap
442
@item vertical_layout
443
@item force_autohint
444
@item crop_bitmap
445
@item pedantic
446
@item ignore_global_advance_width
447
@item no_recurse
448
@item ignore_transform
449
@item monochrome
450
@item linear_design
451
@item no_autohint
452
@item end table
453
@end table
454

    
455
Default value is "render".
456

    
457
For more information consult the documentation for the FT_LOAD_*
458
libfreetype flags.
459

    
460
@item tabsize
461
The size in number of spaces to use for rendering the tab.
462
Default value is 4.
463
@end table
464

    
465
For example the command:
466
@example
467
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
468
@end example
469

    
470
will draw "Test Text" with font FreeSerif, using the default values
471
for the optional parameters.
472

    
473
The command:
474
@example
475
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
476
          x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
477
@end example
478

    
479
will draw 'Test Text' with font FreeSerif of size 24 at position x=100
480
and y=50 (counting from the top-left corner of the screen), text is
481
yellow with a red box around it. Both the text and the box have an
482
opacity of 20%.
483

    
484
Note that the double quotes are not necessary if spaces are not used
485
within the parameter list.
486

    
487
For more information about libfreetype, check:
488
@url{http://www.freetype.org/}.
489

    
490
@section fade
491

    
492
Apply fade-in/out effect to input video.
493

    
494
It accepts the parameters:
495
@var{type}:@var{start_frame}:@var{nb_frames}
496

    
497
@var{type} specifies if the effect type, can be either "in" for
498
fade-in, or "out" for a fade-out effect.
499

    
500
@var{start_frame} specifies the number of the start frame for starting
501
to apply the fade effect.
502

    
503
@var{nb_frames} specifies the number of frames for which the fade
504
effect has to last. At the end of the fade-in effect the output video
505
will have the same intensity as the input video, at the end of the
506
fade-out transition the output video will be completely black.
507

    
508
A few usage examples follow, usable too as test scenarios.
509
@example
510
# fade in first 30 frames of video
511
fade=in:0:30
512

    
513
# fade out last 45 frames of a 200-frame video
514
fade=out:155:45
515

    
516
# fade in first 25 frames and fade out last 25 frames of a 1000-frame video
517
fade=in:0:25, fade=out:975:25
518

    
519
# make first 5 frames black, then fade in from frame 5-24
520
fade=in:5:20
521
@end example
522

    
523
@section fifo
524

    
525
Buffer input images and send them when they are requested.
526

    
527
This filter is mainly useful when auto-inserted by the libavfilter
528
framework.
529

    
530
The filter does not take parameters.
531

    
532
@section format
533

    
534
Convert the input video to one of the specified pixel formats.
535
Libavfilter will try to pick one that is supported for the input to
536
the next filter.
537

    
538
The filter accepts a list of pixel format names, separated by ":",
539
for example "yuv420p:monow:rgb24".
540

    
541
Some examples follow:
542
@example
543
# convert the input video to the format "yuv420p"
544
format=yuv420p
545

    
546
# convert the input video to any of the formats in the list
547
format=yuv420p:yuv444p:yuv410p
548
@end example
549

    
550
@anchor{frei0r}
551
@section frei0r
552

    
553
Apply a frei0r effect to the input video.
554

    
555
To enable compilation of this filter you need to install the frei0r
556
header and configure FFmpeg with --enable-frei0r.
557

    
558
The filter supports the syntax:
559
@example
560
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
561
@end example
562

    
563
@var{filter_name} is the name to the frei0r effect to load. If the
564
environment variable @env{FREI0R_PATH} is defined, the frei0r effect
565
is searched in each one of the directories specified by the colon
566
separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
567
paths, which are in this order: @file{HOME/.frei0r-1/lib/},
568
@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
569

    
570
@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
571
for the frei0r effect.
572

    
573
A frei0r effect parameter can be a boolean (whose values are specified
574
with "y" and "n"), a double, a color (specified by the syntax
575
@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
576
numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
577
description), a position (specified by the syntax @var{X}/@var{Y},
578
@var{X} and @var{Y} being float numbers) and a string.
579

    
580
The number and kind of parameters depend on the loaded effect. If an
581
effect parameter is not specified the default value is set.
582

    
583
Some examples follow:
584
@example
585
# apply the distort0r effect, set the first two double parameters
586
frei0r=distort0r:0.5:0.01
587

    
588
# apply the colordistance effect, takes a color as first parameter
589
frei0r=colordistance:0.2/0.3/0.4
590
frei0r=colordistance:violet
591
frei0r=colordistance:0x112233
592

    
593
# apply the perspective effect, specify the top left and top right
594
# image positions
595
frei0r=perspective:0.2/0.2:0.8/0.2
596
@end example
597

    
598
For more information see:
599
@url{http://piksel.org/frei0r}
600

    
601
@section gradfun
602

    
603
Fix the banding artifacts that are sometimes introduced into nearly flat
604
regions by truncation to 8bit colordepth.
605
Interpolate the gradients that should go where the bands are, and
606
dither them.
607

    
608
This filter is designed for playback only.  Do not use it prior to
609
lossy compression, because compression tends to lose the dither and
610
bring back the bands.
611

    
612
The filter takes two optional parameters, separated by ':':
613
@var{strength}:@var{radius}
614

    
615
@var{strength} is the maximum amount by which the filter will change
616
any one pixel. Also the threshold for detecting nearly flat
617
regions. Acceptable values range from .51 to 255, default value is
618
1.2, out-of-range values will be clipped to the valid range.
619

    
620
@var{radius} is the neighborhood to fit the gradient to. A larger
621
radius makes for smoother gradients, but also prevents the filter from
622
modifying the pixels near detailed regions. Acceptable values are
623
8-32, default value is 16, out-of-range values will be clipped to the
624
valid range.
625

    
626
@example
627
# default parameters
628
gradfun=1.2:16
629

    
630
# omitting radius
631
gradfun=1.2
632
@end example
633

    
634
@section hflip
635

    
636
Flip the input video horizontally.
637

    
638
For example to horizontally flip the video in input with
639
@file{ffmpeg}:
640
@example
641
ffmpeg -i in.avi -vf "hflip" out.avi
642
@end example
643

    
644
@section hqdn3d
645

    
646
High precision/quality 3d denoise filter. This filter aims to reduce
647
image noise producing smooth images and making still images really
648
still. It should enhance compressibility.
649

    
650
It accepts the following optional parameters:
651
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
652

    
653
@table @option
654
@item luma_spatial
655
a non-negative float number which specifies spatial luma strength,
656
defaults to 4.0
657

    
658
@item chroma_spatial
659
a non-negative float number which specifies spatial chroma strength,
660
defaults to 3.0*@var{luma_spatial}/4.0
661

    
662
@item luma_tmp
663
a float number which specifies luma temporal strength, defaults to
664
6.0*@var{luma_spatial}/4.0
665

    
666
@item chroma_tmp
667
a float number which specifies chroma temporal strength, defaults to
668
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
669
@end table
670

    
671
@section mp
672

    
673
Apply an MPlayer filter to the input video.
674

    
675
This filter provides a wrapper around most of the filters of
676
MPlayer/MEncoder.
677

    
678
This wrapper is considered experimental. Some of the wrapped filters
679
may not work properly and we may drop support for them, as they will
680
be implemented natively into FFmpeg. Thus you should avoid
681
depending on them when writing portable scripts.
682

    
683
The filters accepts the parameters:
684
@var{filter_name}[:=]@var{filter_params}
685

    
686
@var{filter_name} is the name of a supported MPlayer filter,
687
@var{filter_params} is a string containing the parameters accepted by
688
the named filter.
689

    
690
The list of the currently supported filters follows:
691
@table @var
692
@item 2xsai
693
@item blackframe
694
@item boxblur
695
@item cropdetect
696
@item decimate
697
@item delogo
698
@item denoise3d
699
@item detc
700
@item dint
701
@item divtc
702
@item down3dright
703
@item dsize
704
@item eq2
705
@item eq
706
@item field
707
@item fil
708
@item fixpts
709
@item framestep
710
@item fspp
711
@item geq
712
@item gradfun
713
@item harddup
714
@item hqdn3d
715
@item hue
716
@item il
717
@item ilpack
718
@item ivtc
719
@item kerndeint
720
@item mcdeint
721
@item mirror
722
@item noise
723
@item ow
724
@item palette
725
@item perspective
726
@item phase
727
@item pp7
728
@item pullup
729
@item qp
730
@item rectangle
731
@item remove_logo
732
@item rgbtest
733
@item rotate
734
@item sab
735
@item screenshot
736
@item smartblur
737
@item softpulldown
738
@item softskip
739
@item spp
740
@item swapuv
741
@item telecine
742
@item test
743
@item tile
744
@item tinterlace
745
@item unsharp
746
@item uspp
747
@item yuvcsp
748
@item yvu9
749
@end table
750

    
751
The parameter syntax and behavior for the listed filters are the same
752
of the corresponding MPlayer filters. For detailed instructions check
753
the "VIDEO FILTERS" section in the MPlayer manual.
754

    
755
Some examples follow:
756
@example
757
# remove a logo by interpolating the surrounding pixels
758
mp=delogo=200:200:80:20:1
759

    
760
# adjust gamma, brightness, contrast
761
mp=eq2=1.0:2:0.5
762

    
763
# tweak hue and saturation
764
mp=hue=100:-10
765
@end example
766

    
767
See also mplayer(1), @url{http://www.mplayerhq.hu/}.
768

    
769
@section noformat
770

    
771
Force libavfilter not to use any of the specified pixel formats for the
772
input to the next filter.
773

    
774
The filter accepts a list of pixel format names, separated by ":",
775
for example "yuv420p:monow:rgb24".
776

    
777
Some examples follow:
778
@example
779
# force libavfilter to use a format different from "yuv420p" for the
780
# input to the vflip filter
781
noformat=yuv420p,vflip
782

    
783
# convert the input video to any of the formats not contained in the list
784
noformat=yuv420p:yuv444p:yuv410p
785
@end example
786

    
787
@section null
788

    
789
Pass the video source unchanged to the output.
790

    
791
@section ocv
792

    
793
Apply video transform using libopencv.
794

    
795
To enable this filter install libopencv library and headers and
796
configure FFmpeg with --enable-libopencv.
797

    
798
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
799

    
800
@var{filter_name} is the name of the libopencv filter to apply.
801

    
802
@var{filter_params} specifies the parameters to pass to the libopencv
803
filter. If not specified the default values are assumed.
804

    
805
Refer to the official libopencv documentation for more precise
806
informations:
807
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
808

    
809
Follows the list of supported libopencv filters.
810

    
811
@anchor{dilate}
812
@subsection dilate
813

    
814
Dilate an image by using a specific structuring element.
815
This filter corresponds to the libopencv function @code{cvDilate}.
816

    
817
It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
818

    
819
@var{struct_el} represents a structuring element, and has the syntax:
820
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
821

    
822
@var{cols} and @var{rows} represent the number of colums and rows of
823
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
824
point, and @var{shape} the shape for the structuring element, and
825
can be one of the values "rect", "cross", "ellipse", "custom".
826

    
827
If the value for @var{shape} is "custom", it must be followed by a
828
string of the form "=@var{filename}". The file with name
829
@var{filename} is assumed to represent a binary image, with each
830
printable character corresponding to a bright pixel. When a custom
831
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
832
or columns and rows of the read file are assumed instead.
833

    
834
The default value for @var{struct_el} is "3x3+0x0/rect".
835

    
836
@var{nb_iterations} specifies the number of times the transform is
837
applied to the image, and defaults to 1.
838

    
839
Follow some example:
840
@example
841
# use the default values
842
ocv=dilate
843

    
844
# dilate using a structuring element with a 5x5 cross, iterate two times
845
ocv=dilate=5x5+2x2/cross:2
846

    
847
# read the shape from the file diamond.shape, iterate two times
848
# the file diamond.shape may contain a pattern of characters like this:
849
#   *
850
#  ***
851
# *****
852
#  ***
853
#   *
854
# the specified cols and rows are ignored (but not the anchor point coordinates)
855
ocv=0x0+2x2/custom=diamond.shape:2
856
@end example
857

    
858
@subsection erode
859

    
860
Erode an image by using a specific structuring element.
861
This filter corresponds to the libopencv function @code{cvErode}.
862

    
863
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
864
with the same meaning and use of those of the dilate filter
865
(@pxref{dilate}).
866

    
867
@subsection smooth
868

    
869
Smooth the input video.
870

    
871
The filter takes the following parameters:
872
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
873

    
874
@var{type} is the type of smooth filter to apply, and can be one of
875
the following values: "blur", "blur_no_scale", "median", "gaussian",
876
"bilateral". The default value is "gaussian".
877

    
878
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
879
parameters whose meanings depend on smooth type. @var{param1} and
880
@var{param2} accept integer positive values or 0, @var{param3} and
881
@var{param4} accept float values.
882

    
883
The default value for @var{param1} is 3, the default value for the
884
other parameters is 0.
885

    
886
These parameters correspond to the parameters assigned to the
887
libopencv function @code{cvSmooth}.
888

    
889
@section overlay
890

    
891
Overlay one video on top of another.
892

    
893
It takes two inputs and one output, the first input is the "main"
894
video on which the second input is overlayed.
895

    
896
It accepts the parameters: @var{x}:@var{y}.
897

    
898
@var{x} is the x coordinate of the overlayed video on the main video,
899
@var{y} is the y coordinate. The parameters are expressions containing
900
the following parameters:
901

    
902
@table @option
903
@item main_w, main_h
904
main input width and height
905

    
906
@item W, H
907
same as @var{main_w} and @var{main_h}
908

    
909
@item overlay_w, overlay_h
910
overlay input width and height
911

    
912
@item w, h
913
same as @var{overlay_w} and @var{overlay_h}
914
@end table
915

    
916
Be aware that frames are taken from each input video in timestamp
917
order, hence, if their initial timestamps differ, it is a a good idea
918
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
919
have them begin in the same zero timestamp, as it does the example for
920
the @var{movie} filter.
921

    
922
Follow some examples:
923
@example
924
# draw the overlay at 10 pixels from the bottom right
925
# corner of the main video.
926
overlay=main_w-overlay_w-10:main_h-overlay_h-10
927

    
928
# insert a transparent PNG logo in the bottom left corner of the input
929
movie=logo.png [logo];
930
[in][logo] overlay=10:main_h-overlay_h-10 [out]
931

    
932
# insert 2 different transparent PNG logos (second logo on bottom
933
# right corner):
934
movie=logo1.png [logo1];
935
movie=logo2.png [logo2];
936
[in][logo1]       overlay=10:H-h-10 [in+logo1];
937
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
938

    
939
# add a transparent color layer on top of the main video,
940
# WxH specifies the size of the main input to the overlay filter
941
color=red@.3:WxH [over]; [in][over] overlay [out]
942
@end example
943

    
944
You can chain togheter more overlays but the efficiency of such
945
approach is yet to be tested.
946

    
947
@section pad
948

    
949
Add paddings to the input image, and places the original input at the
950
given coordinates @var{x}, @var{y}.
951

    
952
It accepts the following parameters:
953
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
954

    
955
Follows the description of the accepted parameters.
956

    
957
@table @option
958
@item width, height
959

    
960
Specify the size of the output image with the paddings added. If the
961
value for @var{width} or @var{height} is 0, the corresponding input size
962
is used for the output.
963

    
964
The default value of @var{width} and @var{height} is 0.
965

    
966
@item x, y
967

    
968
Specify the offsets where to place the input image in the padded area
969
with respect to the top/left border of the output image.
970

    
971
The default value of @var{x} and @var{y} is 0.
972

    
973
@item color
974

    
975
Specify the color of the padded area, it can be the name of a color
976
(case insensitive match) or a 0xRRGGBB[AA] sequence.
977

    
978
The default value of @var{color} is "black".
979

    
980
@end table
981

    
982
For example:
983

    
984
@example
985
# Add paddings with color "violet" to the input video. Output video
986
# size is 640x480, the top-left corner of the input video is placed at
987
# row 0, column 40.
988
pad=640:480:0:40:violet
989
@end example
990

    
991
@section pixdesctest
992

    
993
Pixel format descriptor test filter, mainly useful for internal
994
testing. The output video should be equal to the input video.
995

    
996
For example:
997
@example
998
format=monow, pixdesctest
999
@end example
1000

    
1001
can be used to test the monowhite pixel format descriptor definition.
1002

    
1003
@section scale
1004

    
1005
Scale the input video to @var{width}:@var{height} and/or convert the image format.
1006

    
1007
For example the command:
1008

    
1009
@example
1010
./ffmpeg -i in.avi -vf "scale=200:100" out.avi
1011
@end example
1012

    
1013
will scale the input video to a size of 200x100.
1014

    
1015
If the input image format is different from the format requested by
1016
the next filter, the scale filter will convert the input to the
1017
requested format.
1018

    
1019
If the value for @var{width} or @var{height} is 0, the respective input
1020
size is used for the output.
1021

    
1022
If the value for @var{width} or @var{height} is -1, the scale filter will
1023
use, for the respective output size, a value that maintains the aspect
1024
ratio of the input image.
1025

    
1026
The default value of @var{width} and @var{height} is 0.
1027

    
1028
@anchor{setdar}
1029
@section setdar
1030

    
1031
Set the Display Aspect Ratio for the filter output video.
1032

    
1033
This is done by changing the specified Sample (aka Pixel) Aspect
1034
Ratio, according to the following equation:
1035
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1036

    
1037
Keep in mind that this filter does not modify the pixel dimensions of
1038
the video frame. Also the display aspect ratio set by this filter may
1039
be changed by later filters in the filterchain, e.g. in case of
1040
scaling or if another "setdar" or a "setsar" filter is applied.
1041

    
1042
The filter accepts a parameter string which represents the wanted
1043
display aspect ratio.
1044
The parameter can be a floating point number string, or an expression
1045
of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1046
numerator and denominator of the aspect ratio.
1047
If the parameter is not specified, it is assumed the value "0:1".
1048

    
1049
For example to change the display aspect ratio to 16:9, specify:
1050
@example
1051
setdar=16:9
1052
# the above is equivalent to
1053
setdar=1.77777
1054
@end example
1055

    
1056
See also the "setsar" filter documentation (@pxref{setsar}).
1057

    
1058
@section setpts
1059

    
1060
Change the PTS (presentation timestamp) of the input video frames.
1061

    
1062
Accept in input an expression evaluated through the eval API, which
1063
can contain the following constants:
1064

    
1065
@table @option
1066
@item PTS
1067
the presentation timestamp in input
1068

    
1069
@item PI
1070
Greek PI
1071

    
1072
@item PHI
1073
golden ratio
1074

    
1075
@item E
1076
Euler number
1077

    
1078
@item N
1079
the count of the input frame, starting from 0.
1080

    
1081
@item STARTPTS
1082
the PTS of the first video frame
1083

    
1084
@item INTERLACED
1085
tell if the current frame is interlaced
1086

    
1087
@item POS
1088
original position in the file of the frame, or undefined if undefined
1089
for the current frame
1090

    
1091
@item PREV_INPTS
1092
previous input PTS
1093

    
1094
@item PREV_OUTPTS
1095
previous output PTS
1096

    
1097
@end table
1098

    
1099
Some examples follow:
1100

    
1101
@example
1102
# start counting PTS from zero
1103
setpts=PTS-STARTPTS
1104

    
1105
# fast motion
1106
setpts=0.5*PTS
1107

    
1108
# slow motion
1109
setpts=2.0*PTS
1110

    
1111
# fixed rate 25 fps
1112
setpts=N/(25*TB)
1113

    
1114
# fixed rate 25 fps with some jitter
1115
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1116
@end example
1117

    
1118
@anchor{setsar}
1119
@section setsar
1120

    
1121
Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1122

    
1123
Note that as a consequence of the application of this filter, the
1124
output display aspect ratio will change according to the following
1125
equation:
1126
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1127

    
1128
Keep in mind that the sample aspect ratio set by this filter may be
1129
changed by later filters in the filterchain, e.g. if another "setsar"
1130
or a "setdar" filter is applied.
1131

    
1132
The filter accepts a parameter string which represents the wanted
1133
sample aspect ratio.
1134
The parameter can be a floating point number string, or an expression
1135
of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1136
numerator and denominator of the aspect ratio.
1137
If the parameter is not specified, it is assumed the value "0:1".
1138

    
1139
For example to change the sample aspect ratio to 10:11, specify:
1140
@example
1141
setsar=10:11
1142
@end example
1143

    
1144
@section settb
1145

    
1146
Set the timebase to use for the output frames timestamps.
1147
It is mainly useful for testing timebase configuration.
1148

    
1149
It accepts in input an arithmetic expression representing a rational.
1150
The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1151
default timebase), and "intb" (the input timebase).
1152

    
1153
The default value for the input is "intb".
1154

    
1155
Follow some examples.
1156

    
1157
@example
1158
# set the timebase to 1/25
1159
settb=1/25
1160

    
1161
# set the timebase to 1/10
1162
settb=0.1
1163

    
1164
#set the timebase to 1001/1000
1165
settb=1+0.001
1166

    
1167
#set the timebase to 2*intb
1168
settb=2*intb
1169

    
1170
#set the default timebase value
1171
settb=AVTB
1172
@end example
1173

    
1174
@section slicify
1175

    
1176
Pass the images of input video on to next video filter as multiple
1177
slices.
1178

    
1179
@example
1180
./ffmpeg -i in.avi -vf "slicify=32" out.avi
1181
@end example
1182

    
1183
The filter accepts the slice height as parameter. If the parameter is
1184
not specified it will use the default value of 16.
1185

    
1186
Adding this in the beginning of filter chains should make filtering
1187
faster due to better use of the memory cache.
1188

    
1189
@section transpose
1190

    
1191
Transpose rows with columns in the input video and optionally flip it.
1192

    
1193
It accepts a parameter representing an integer, which can assume the
1194
values:
1195

    
1196
@table @samp
1197
@item 0
1198
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
1199
@example
1200
L.R     L.l
1201
. . ->  . .
1202
l.r     R.r
1203
@end example
1204

    
1205
@item 1
1206
Rotate by 90 degrees clockwise, that is:
1207
@example
1208
L.R     l.L
1209
. . ->  . .
1210
l.r     r.R
1211
@end example
1212

    
1213
@item 2
1214
Rotate by 90 degrees counterclockwise, that is:
1215
@example
1216
L.R     R.r
1217
. . ->  . .
1218
l.r     L.l
1219
@end example
1220

    
1221
@item 3
1222
Rotate by 90 degrees clockwise and vertically flip, that is:
1223
@example
1224
L.R     r.R
1225
. . ->  . .
1226
l.r     l.L
1227
@end example
1228
@end table
1229

    
1230
@section unsharp
1231

    
1232
Sharpen or blur the input video.
1233

    
1234
It accepts the following parameters:
1235
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
1236

    
1237
Negative values for the amount will blur the input video, while positive
1238
values will sharpen. All parameters are optional and default to the
1239
equivalent of the string '5:5:1.0:0:0:0.0'.
1240

    
1241
@table @option
1242

    
1243
@item luma_msize_x
1244
Set the luma matrix horizontal size. It can be an integer between 3
1245
and 13, default value is 5.
1246

    
1247
@item luma_msize_y
1248
Set the luma matrix vertical size. It can be an integer between 3
1249
and 13, default value is 5.
1250

    
1251
@item luma_amount
1252
Set the luma effect strength. It can be a float number between -2.0
1253
and 5.0, default value is 1.0.
1254

    
1255
@item chroma_msize_x
1256
Set the chroma matrix horizontal size. It can be an integer between 3
1257
and 13, default value is 0.
1258

    
1259
@item chroma_msize_y
1260
Set the chroma matrix vertical size. It can be an integer between 3
1261
and 13, default value is 0.
1262

    
1263
@item luma_amount
1264
Set the chroma effect strength. It can be a float number between -2.0
1265
and 5.0, default value is 0.0.
1266

    
1267
@end table
1268

    
1269
@example
1270
# Strong luma sharpen effect parameters
1271
unsharp=7:7:2.5
1272

    
1273
# Strong blur of both luma and chroma parameters
1274
unsharp=7:7:-2:7:7:-2
1275

    
1276
# Use the default values with @command{ffmpeg}
1277
./ffmpeg -i in.avi -vf "unsharp" out.mp4
1278
@end example
1279

    
1280
@section vflip
1281

    
1282
Flip the input video vertically.
1283

    
1284
@example
1285
./ffmpeg -i in.avi -vf "vflip" out.avi
1286
@end example
1287

    
1288
@section yadif
1289

    
1290
Deinterlace the input video ("yadif" means "yet another deinterlacing
1291
filter").
1292

    
1293
It accepts the optional parameters: @var{mode}:@var{parity}.
1294

    
1295
@var{mode} specifies the interlacing mode to adopt, accepts one of the
1296
following values:
1297

    
1298
@table @option
1299
@item 0
1300
output 1 frame for each frame
1301
@item 1
1302
output 1 frame for each field
1303
@item 2
1304
like 0 but skips spatial interlacing check
1305
@item 3
1306
like 1 but skips spatial interlacing check
1307
@end table
1308

    
1309
Default value is 0.
1310

    
1311
@var{parity} specifies the picture field parity assumed for the input
1312
interlaced video, accepts one of the following values:
1313

    
1314
@table @option
1315
@item 0
1316
assume bottom field first
1317
@item 1
1318
assume top field first
1319
@item -1
1320
enable automatic detection
1321
@end table
1322

    
1323
Default value is -1.
1324
If interlacing is unknown or decoder does not export this information,
1325
top field first will be assumed.
1326

    
1327
@c man end VIDEO FILTERS
1328

    
1329
@chapter Video Sources
1330
@c man begin VIDEO SOURCES
1331

    
1332
Below is a description of the currently available video sources.
1333

    
1334
@section buffer
1335

    
1336
Buffer video frames, and make them available to the filter chain.
1337

    
1338
This source is mainly intended for a programmatic use, in particular
1339
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1340

    
1341
It accepts the following parameters:
1342
@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
1343

    
1344
All the parameters need to be explicitely defined.
1345

    
1346
Follows the list of the accepted parameters.
1347

    
1348
@table @option
1349

    
1350
@item width, height
1351
Specify the width and height of the buffered video frames.
1352

    
1353
@item pix_fmt_string
1354
A string representing the pixel format of the buffered video frames.
1355
It may be a number corresponding to a pixel format, or a pixel format
1356
name.
1357

    
1358
@item timebase_num, timebase_den
1359
Specify numerator and denomitor of the timebase assumed by the
1360
timestamps of the buffered frames.
1361

    
1362
@item sample_aspect_ratio.num, sample_aspect_ratio.den
1363
Specify numerator and denominator of the sample aspect ratio assumed
1364
by the video frames.
1365
@end table
1366

    
1367
For example:
1368
@example
1369
buffer=320:240:yuv410p:1:24:1:1
1370
@end example
1371

    
1372
will instruct the source to accept video frames with size 320x240 and
1373
with format "yuv410p", assuming 1/24 as the timestamps timebase and
1374
square pixels (1:1 sample aspect ratio).
1375
Since the pixel format with name "yuv410p" corresponds to the number 6
1376
(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1377
this example corresponds to:
1378
@example
1379
buffer=320:240:6:1:24
1380
@end example
1381

    
1382
@section color
1383

    
1384
Provide an uniformly colored input.
1385

    
1386
It accepts the following parameters:
1387
@var{color}:@var{frame_size}:@var{frame_rate}
1388

    
1389
Follows the description of the accepted parameters.
1390

    
1391
@table @option
1392

    
1393
@item color
1394
Specify the color of the source. It can be the name of a color (case
1395
insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1396
alpha specifier. The default value is "black".
1397

    
1398
@item frame_size
1399
Specify the size of the sourced video, it may be a string of the form
1400
@var{width}x@var{heigth}, or the name of a size abbreviation. The
1401
default value is "320x240".
1402

    
1403
@item frame_rate
1404
Specify the frame rate of the sourced video, as the number of frames
1405
generated per second. It has to be a string in the format
1406
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1407
number or a valid video frame rate abbreviation. The default value is
1408
"25".
1409

    
1410
@end table
1411

    
1412
For example the following graph description will generate a red source
1413
with an opacity of 0.2, with size "qcif" and a frame rate of 10
1414
frames per second, which will be overlayed over the source connected
1415
to the pad with identifier "in".
1416

    
1417
@example
1418
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1419
@end example
1420

    
1421
@section movie
1422

    
1423
Read a video stream from a movie container.
1424

    
1425
It accepts the syntax: @var{movie_name}[:@var{options}] where
1426
@var{movie_name} is the name of the resource to read (not necessarily
1427
a file but also a device or a stream accessed through some protocol),
1428
and @var{options} is an optional sequence of @var{key}=@var{value}
1429
pairs, separated by ":".
1430

    
1431
The description of the accepted options follows.
1432

    
1433
@table @option
1434

    
1435
@item format_name, f
1436
Specifies the format assumed for the movie to read, and can be either
1437
the name of a container or an input device. If not specified the
1438
format is guessed from @var{movie_name} or by probing.
1439

    
1440
@item seek_point, sp
1441
Specifies the seek point in seconds, the frames will be output
1442
starting from this seek point, the parameter is evaluated with
1443
@code{av_strtod} so the numerical value may be suffixed by an IS
1444
postfix. Default value is "0".
1445

    
1446
@item stream_index, si
1447
Specifies the index of the video stream to read. If the value is -1,
1448
the best suited video stream will be automatically selected. Default
1449
value is "-1".
1450

    
1451
@end table
1452

    
1453
This filter allows to overlay a second video on top of main input of
1454
a filtergraph as shown in this graph:
1455
@example
1456
input -----------> deltapts0 --> overlay --> output
1457
                                    ^
1458
                                    |
1459
movie --> scale--> deltapts1 -------+
1460
@end example
1461

    
1462
Some examples follow:
1463
@example
1464
# skip 3.2 seconds from the start of the avi file in.avi, and overlay it
1465
# on top of the input labelled as "in".
1466
movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1467
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1468

    
1469
# read from a video4linux2 device, and overlay it on top of the input
1470
# labelled as "in"
1471
movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
1472
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
1473

    
1474
@end example
1475

    
1476
@section nullsrc
1477

    
1478
Null video source, never return images. It is mainly useful as a
1479
template and to be employed in analysis / debugging tools.
1480

    
1481
It accepts as optional parameter a string of the form
1482
@var{width}:@var{height}:@var{timebase}.
1483

    
1484
@var{width} and @var{height} specify the size of the configured
1485
source. The default values of @var{width} and @var{height} are
1486
respectively 352 and 288 (corresponding to the CIF size format).
1487

    
1488
@var{timebase} specifies an arithmetic expression representing a
1489
timebase. The expression can contain the constants "PI", "E", "PHI",
1490
"AVTB" (the default timebase), and defaults to the value "AVTB".
1491

    
1492
@section frei0r_src
1493

    
1494
Provide a frei0r source.
1495

    
1496
To enable compilation of this filter you need to install the frei0r
1497
header and configure FFmpeg with --enable-frei0r.
1498

    
1499
The source supports the syntax:
1500
@example
1501
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1502
@end example
1503

    
1504
@var{size} is the size of the video to generate, may be a string of the
1505
form @var{width}x@var{height} or a frame size abbreviation.
1506
@var{rate} is the rate of the video to generate, may be a string of
1507
the form @var{num}/@var{den} or a frame rate abbreviation.
1508
@var{src_name} is the name to the frei0r source to load. For more
1509
information regarding frei0r and how to set the parameters read the
1510
section "frei0r" (@pxref{frei0r}) in the description of the video
1511
filters.
1512

    
1513
Some examples follow:
1514
@example
1515
# generate a frei0r partik0l source with size 200x200 and framerate 10
1516
# which is overlayed on the overlay filter main input
1517
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1518
@end example
1519

    
1520
@c man end VIDEO SOURCES
1521

    
1522
@chapter Video Sinks
1523
@c man begin VIDEO SINKS
1524

    
1525
Below is a description of the currently available video sinks.
1526

    
1527
@section nullsink
1528

    
1529
Null video sink, do absolutely nothing with the input video. It is
1530
mainly useful as a template and to be employed in analysis / debugging
1531
tools.
1532

    
1533
@c man end VIDEO SINKS
1534