Statistics
| Branch: | Revision:

ffmpeg / doc / filters.texi @ 106f271f

History | View | Annotate | Download (32.3 KB)

1 1ebe5c4c Stefano Sabatini
@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 f59e9eaf Stefano Sabatini
@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 99046339 S.N. Hemanth Meenakshisundaram
@section anull
103
104
Pass the audio source unchanged to the output.
105
106 f59e9eaf Stefano Sabatini
@c man end AUDIO FILTERS
107
108 1ee410f3 Stefano Sabatini
@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 6ef93402 Stefano Sabatini
@file{libavcodec/audioconvert.c} for the mapping between strings and
129
channel layout values.
130 1ee410f3 Stefano Sabatini
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 f0a55438 S.N. Hemanth Meenakshisundaram
@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 3275ac6a Stefano Sabatini
@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 13fabd7a Stefano Sabatini
@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 3275ac6a Stefano Sabatini
@section crop
187
188 75b67a8a Stefano Sabatini
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
189 3275ac6a Stefano Sabatini
190 75b67a8a Stefano Sabatini
The parameters are expressions containing the following constants:
191
192
@table @option
193
@item E, PI, PHI
194
the corresponding mathematical approximated values for e
195
(euler number), pi (greek PI), PHI (golden ratio)
196
197
@item x, y
198
the computed values for @var{x} and @var{y}. They are evaluated for
199
each new frame.
200
201
@item in_w, in_h
202
the input width and heigth
203
204
@item iw, ih
205
same as @var{in_w} and @var{in_h}
206
207
@item out_w, out_h
208
the output (cropped) width and heigth
209
210
@item ow, oh
211
same as @var{out_w} and @var{out_h}
212
213
@item n
214
the number of input frame, starting from 0
215
216
@item pos
217
the position in the file of the input frame, NAN if unknown
218
219
@item t
220
timestamp expressed in seconds, NAN if the input timestamp is unknown
221 3275ac6a Stefano Sabatini
222 75b67a8a Stefano Sabatini
@end table
223 3275ac6a Stefano Sabatini
224 75b67a8a Stefano Sabatini
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.
227 3275ac6a Stefano Sabatini
228 75b67a8a Stefano Sabatini
The default value of @var{out_w} is "in_w", and the default value of
229
@var{out_h} is "in_h".
230 2bc05d35 Stefano Sabatini
231 75b67a8a Stefano Sabatini
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}.
235 2bc05d35 Stefano Sabatini
236 75b67a8a Stefano Sabatini
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.
240 3275ac6a Stefano Sabatini
241 75b67a8a Stefano Sabatini
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.
244
245
The expression for @var{x} may depend on @var{y}, and the expression
246
for @var{y} may depend on @var{x}.
247
248
Follow some examples:
249 3275ac6a Stefano Sabatini
@example
250 75b67a8a Stefano Sabatini
# crop the central input area with size 100x100
251
crop=100:100
252
253
# crop the central input area with size 2/3 of the input video
254
"crop=2/3*in_w:2/3*in_h"
255
256
# crop the input video central square
257
crop=in_h
258
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
263 3275ac6a Stefano Sabatini
264 75b67a8a Stefano Sabatini
# 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"
267 3275ac6a Stefano Sabatini
268 75b67a8a Stefano Sabatini
# keep only the bottom right quarter of the input image
269
"crop=in_w/2:in_h/2:in_w/2:in_h/2"
270
271
# crop height for getting Greek harmony
272
"crop=in_w:1/PHI*in_w"
273
274
# trembling effect
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)"
276
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)"
279
280
# set x depending on the value of y
281
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
282
@end example
283 3275ac6a Stefano Sabatini
284 68b79bfc Stefano Sabatini
@section cropdetect
285
286
Auto-detect crop size.
287
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.
291
292
It accepts the syntax:
293
@example
294 3699c1f1 Stefano Sabatini
cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
295 68b79bfc Stefano Sabatini
@end example
296
297
@table @option
298
299
@item limit
300
Threshold, which can be optionally specified from nothing (0) to
301
everything (255), defaults to 24.
302
303
@item round
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.
308
309
@item reset
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.
313
314
This can be useful when channel logos distort the video area. 0
315
indicates never reset and return the largest area encountered during
316
playback.
317
@end table
318
319 e40032e2 Stefano Sabatini
@section drawbox
320
321
Draw a colored box on the input image.
322
323
It accepts the syntax:
324
@example
325
drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
326
@end example
327
328
@table @option
329
330
@item x, y
331
Specify the top left corner coordinates of the box. Default to 0.
332
333
@item width, height
334
Specify the width and height of the box, if 0 they are interpreted as
335
the input width and height. Default to 0.
336
337
@item color
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.
340
@end table
341
342
Follow some examples:
343
@example
344
# draw a black box around the edge of the input image
345
drawbox
346
347
# draw a box with color red and an opacity of 50%
348
drawbox=10:20:200:60:red@@0.5"
349
@end example
350
351 7f1af825 Stefano Sabatini
@section fifo
352
353
Buffer input images and send them when they are requested.
354
355
This filter is mainly useful when auto-inserted by the libavfilter
356
framework.
357
358
The filter does not take parameters.
359
360 3275ac6a Stefano Sabatini
@section format
361
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
364
the next filter.
365
366 b1094275 Stefano Sabatini
The filter accepts a list of pixel format names, separated by ":",
367
for example "yuv420p:monow:rgb24".
368 3275ac6a Stefano Sabatini
369 f150e4dc Stefano Sabatini
Some examples follow:
370 3275ac6a Stefano Sabatini
@example
371 f150e4dc Stefano Sabatini
# convert the input video to the format "yuv420p"
372
format=yuv420p
373 3275ac6a Stefano Sabatini
374 f150e4dc Stefano Sabatini
# convert the input video to any of the formats in the list
375
format=yuv420p:yuv444p:yuv410p
376
@end example
377 3275ac6a Stefano Sabatini
378 f8608dca Stefano Sabatini
@anchor{frei0r}
379 47941088 Stefano Sabatini
@section frei0r
380
381
Apply a frei0r effect to the input video.
382
383
To enable compilation of this filter you need to install the frei0r
384
header and configure FFmpeg with --enable-frei0r.
385
386
The filter supports the syntax:
387
@example
388 f51aeedd Stefano Sabatini
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
389 47941088 Stefano Sabatini
@end example
390
391
@var{filter_name} is the name to the frei0r effect to load. If the
392
environment variable @env{FREI0R_PATH} is defined, the frei0r effect
393
is searched in each one of the directories specified by the colon
394
separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
395
paths, which are in this order: @file{HOME/.frei0r-1/lib/},
396
@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
397
398
@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
399
for the frei0r effect.
400
401
A frei0r effect parameter can be a boolean (whose values are specified
402
with "y" and "n"), a double, a color (specified by the syntax
403
@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
404
numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
405
description), a position (specified by the syntax @var{X}/@var{Y},
406
@var{X} and @var{Y} being float numbers) and a string.
407
408
The number and kind of parameters depend on the loaded effect. If an
409
effect parameter is not specified the default value is set.
410
411
Some examples follow:
412
@example
413
# apply the distort0r effect, set the first two double parameters
414
frei0r=distort0r:0.5:0.01
415
416
# apply the colordistance effect, takes a color as first parameter
417
frei0r=colordistance:0.2/0.3/0.4
418
frei0r=colordistance:violet
419
frei0r=colordistance:0x112233
420
421
# apply the perspective effect, specify the top left and top right
422
# image positions
423
frei0r=perspective:0.2/0.2:0.8/0.2
424
@end example
425
426
For more information see:
427
@url{http://piksel.org/frei0r}
428
429 d5f187fd Nolan L
@section gradfun
430
431
Fix the banding artifacts that are sometimes introduced into nearly flat
432
regions by truncation to 8bit colordepth.
433
Interpolate the gradients that should go where the bands are, and
434
dither them.
435
436
The filter takes two optional parameters, separated by ':':
437
@var{strength}:@var{radius}
438
439
@var{strength} is the maximum amount by which the filter will change
440
any one pixel. Also the threshold for detecting nearly flat
441
regions. Acceptable values range from .51 to 255, default value is
442
1.2, out-of-range values will be clipped to the valid range.
443
444
@var{radius} is the neighborhood to fit the gradient to. A larger
445
radius makes for smoother gradients, but also prevents the filter from
446
modifying the pixels near detailed regions. Acceptable values are
447
8-32, default value is 16, out-of-range values will be clipped to the
448
valid range.
449
450
@example
451
# default parameters
452
gradfun=1.2:16
453
454
# omitting radius
455
gradfun=1.2
456
@end example
457
458 a1e171df Stefano Sabatini
@section hflip
459
460
Flip the input video horizontally.
461
462
For example to horizontally flip the video in input with
463
@file{ffmpeg}:
464
@example
465
ffmpeg -i in.avi -vf "hflip" out.avi
466
@end example
467
468 a4dc7aa5 Baptiste Coudurier
@section hqdn3d
469
470
High precision/quality 3d denoise filter. This filter aims to reduce
471
image noise producing smooth images and making still images really
472
still. It should enhance compressibility.
473
474
It accepts the following optional parameters:
475
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
476
477
@table @option
478
@item luma_spatial
479
a non-negative float number which specifies spatial luma strength,
480
defaults to 4.0
481
482
@item chroma_spatial
483
a non-negative float number which specifies spatial chroma strength,
484
defaults to 3.0*@var{luma_spatial}/4.0
485
486
@item luma_tmp
487
a float number which specifies luma temporal strength, defaults to
488
6.0*@var{luma_spatial}/4.0
489
490
@item chroma_tmp
491
a float number which specifies chroma temporal strength, defaults to
492
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
493
@end table
494
495 3275ac6a Stefano Sabatini
@section noformat
496
497
Force libavfilter not to use any of the specified pixel formats for the
498
input to the next filter.
499
500 b1094275 Stefano Sabatini
The filter accepts a list of pixel format names, separated by ":",
501
for example "yuv420p:monow:rgb24".
502 3275ac6a Stefano Sabatini
503 f150e4dc Stefano Sabatini
Some examples follow:
504 3275ac6a Stefano Sabatini
@example
505 f150e4dc Stefano Sabatini
# force libavfilter to use a format different from "yuv420p" for the
506
# input to the vflip filter
507
noformat=yuv420p,vflip
508 3275ac6a Stefano Sabatini
509 f150e4dc Stefano Sabatini
# convert the input video to any of the formats not contained in the list
510
noformat=yuv420p:yuv444p:yuv410p
511
@end example
512 3275ac6a Stefano Sabatini
513
@section null
514
515 99046339 S.N. Hemanth Meenakshisundaram
Pass the video source unchanged to the output.
516 3275ac6a Stefano Sabatini
517 cf69ad35 Stefano Sabatini
@section ocv
518 6ebf0bfc Stefano Sabatini
519 cf69ad35 Stefano Sabatini
Apply video transform using libopencv.
520 6ebf0bfc Stefano Sabatini
521
To enable this filter install libopencv library and headers and
522
configure FFmpeg with --enable-libopencv.
523
524 cf69ad35 Stefano Sabatini
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
525
526
@var{filter_name} is the name of the libopencv filter to apply.
527
528
@var{filter_params} specifies the parameters to pass to the libopencv
529
filter. If not specified the default values are assumed.
530
531
Refer to the official libopencv documentation for more precise
532
informations:
533
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
534
535
Follows the list of supported libopencv filters.
536
537 17fc9493 Stefano Sabatini
@anchor{dilate}
538 91cbb6ba Stefano Sabatini
@subsection dilate
539
540
Dilate an image by using a specific structuring element.
541
This filter corresponds to the libopencv function @code{cvDilate}.
542
543
It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
544
545
@var{struct_el} represents a structuring element, and has the syntax:
546
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
547
548
@var{cols} and @var{rows} represent the number of colums and rows of
549
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
550
point, and @var{shape} the shape for the structuring element, and
551
can be one of the values "rect", "cross", "ellipse", "custom".
552
553
If the value for @var{shape} is "custom", it must be followed by a
554
string of the form "=@var{filename}". The file with name
555
@var{filename} is assumed to represent a binary image, with each
556
printable character corresponding to a bright pixel. When a custom
557
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
558
or columns and rows of the read file are assumed instead.
559
560
The default value for @var{struct_el} is "3x3+0x0/rect".
561
562
@var{nb_iterations} specifies the number of times the transform is
563
applied to the image, and defaults to 1.
564
565
Follow some example:
566
@example
567
# use the default values
568
ocv=dilate
569
570
# dilate using a structuring element with a 5x5 cross, iterate two times
571
ocv=dilate=5x5+2x2/cross:2
572
573
# read the shape from the file diamond.shape, iterate two times
574
# the file diamond.shape may contain a pattern of characters like this:
575
#   *
576
#  ***
577
# *****
578
#  ***
579
#   *
580
# the specified cols and rows are ignored (but not the anchor point coordinates)
581
ocv=0x0+2x2/custom=diamond.shape:2
582
@end example
583
584 17fc9493 Stefano Sabatini
@subsection erode
585
586
Erode an image by using a specific structuring element.
587
This filter corresponds to the libopencv function @code{cvErode}.
588
589
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
590
with the same meaning and use of those of the dilate filter
591
(@pxref{dilate}).
592
593 cf69ad35 Stefano Sabatini
@subsection smooth
594
595
Smooth the input video.
596
597
The filter takes the following parameters:
598 6ebf0bfc Stefano Sabatini
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
599
600
@var{type} is the type of smooth filter to apply, and can be one of
601 58d94364 Stefano Sabatini
the following values: "blur", "blur_no_scale", "median", "gaussian",
602 6ebf0bfc Stefano Sabatini
"bilateral". The default value is "gaussian".
603
604
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
605
parameters whose meanings depend on smooth type. @var{param1} and
606
@var{param2} accept integer positive values or 0, @var{param3} and
607
@var{param4} accept float values.
608
609
The default value for @var{param1} is 3, the default value for the
610
other parameters is 0.
611
612 58d94364 Stefano Sabatini
These parameters correspond to the parameters assigned to the
613 cf69ad35 Stefano Sabatini
libopencv function @code{cvSmooth}.
614 6ebf0bfc Stefano Sabatini
615 58935b25 Stefano Sabatini
@section overlay
616
617
Overlay one video on top of another.
618
619
It takes two inputs and one output, the first input is the "main"
620
video on which the second input is overlayed.
621
622
It accepts the parameters: @var{x}:@var{y}.
623
624
@var{x} is the x coordinate of the overlayed video on the main video,
625
@var{y} is the y coordinate. The parameters are expressions containing
626
the following parameters:
627
628
@table @option
629
@item main_w, main_h
630
main input width and height
631
632
@item W, H
633
same as @var{main_w} and @var{main_h}
634
635
@item overlay_w, overlay_h
636
overlay input width and height
637
638
@item w, h
639
same as @var{overlay_w} and @var{overlay_h}
640
@end table
641
642
Be aware that frames are taken from each input video in timestamp
643
order, hence, if their initial timestamps differ, it is a a good idea
644
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
645
have them begin in the same zero timestamp, as it does the example for
646
the @var{movie} filter.
647
648
Follow some examples:
649
@example
650
# draw the overlay at 10 pixels from the bottom right
651
# corner of the main video.
652
overlay=main_w-overlay_w-10:main_h-overlay_h-10
653
654
# insert a transparent PNG logo in the bottom left corner of the input
655
movie=0:png:logo.png [logo];
656
[in][logo] overlay=10:main_h-overlay_h-10 [out]
657
658
# insert 2 different transparent PNG logos (second logo on bottom
659
# right corner):
660
movie=0:png:logo1.png [logo1];
661
movie=0:png:logo2.png [logo2];
662
[in][logo1]       overlay=10:H-h-10 [in+logo1];
663
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
664
665
# add a transparent color layer on top of the main video,
666
# WxH specifies the size of the main input to the overlay filter
667
color=red@.3:WxH [over]; [in][over] overlay [out]
668
@end example
669
670
You can chain togheter more overlays but the efficiency of such
671
approach is yet to be tested.
672
673 3275ac6a Stefano Sabatini
@section pad
674
675
Add paddings to the input image, and places the original input at the
676
given coordinates @var{x}, @var{y}.
677
678
It accepts the following parameters:
679
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
680
681
Follows the description of the accepted parameters.
682
683
@table @option
684
@item width, height
685
686
Specify the size of the output image with the paddings added. If the
687
value for @var{width} or @var{height} is 0, the corresponding input size
688
is used for the output.
689
690
The default value of @var{width} and @var{height} is 0.
691
692
@item x, y
693
694
Specify the offsets where to place the input image in the padded area
695
with respect to the top/left border of the output image.
696
697
The default value of @var{x} and @var{y} is 0.
698
699
@item color
700
701
Specify the color of the padded area, it can be the name of a color
702
(case insensitive match) or a 0xRRGGBB[AA] sequence.
703
704 b1094275 Stefano Sabatini
The default value of @var{color} is "black".
705 3275ac6a Stefano Sabatini
706
@end table
707
708 3d17f4b9 Stefano Sabatini
For example:
709
710
@example
711
# Add paddings with color "violet" to the input video. Output video
712
# size is 640x480, the top-left corner of the input video is placed at
713
# row 0, column 40.
714
pad=640:480:0:40:violet
715
@end example
716
717 ce2e4ae3 Stefano Sabatini
@section pixdesctest
718
719
Pixel format descriptor test filter, mainly useful for internal
720
testing. The output video should be equal to the input video.
721
722
For example:
723
@example
724
format=monow, pixdesctest
725
@end example
726
727
can be used to test the monowhite pixel format descriptor definition.
728
729 3275ac6a Stefano Sabatini
@section scale
730
731
Scale the input video to @var{width}:@var{height} and/or convert the image format.
732
733
For example the command:
734
735
@example
736
./ffmpeg -i in.avi -vf "scale=200:100" out.avi
737
@end example
738
739
will scale the input video to a size of 200x100.
740
741
If the input image format is different from the format requested by
742
the next filter, the scale filter will convert the input to the
743
requested format.
744
745
If the value for @var{width} or @var{height} is 0, the respective input
746
size is used for the output.
747
748
If the value for @var{width} or @var{height} is -1, the scale filter will
749
use, for the respective output size, a value that maintains the aspect
750
ratio of the input image.
751
752
The default value of @var{width} and @var{height} is 0.
753
754 a532bb39 Stefano Sabatini
@section setpts
755
756
Change the PTS (presentation timestamp) of the input video frames.
757
758
Accept in input an expression evaluated through the eval API, which
759
can contain the following constants:
760
761
@table @option
762
@item PTS
763
the presentation timestamp in input
764
765
@item PI
766
Greek PI
767
768
@item PHI
769
golden ratio
770
771
@item E
772
Euler number
773
774
@item N
775
the count of the input frame, starting from 0.
776
777
@item STARTPTS
778
the PTS of the first video frame
779
780
@item INTERLACED
781
tell if the current frame is interlaced
782
783
@item POS
784
original position in the file of the frame, or undefined if undefined
785
for the current frame
786
787
@item PREV_INPTS
788
previous input PTS
789
790
@item PREV_OUTPTS
791
previous output PTS
792
793
@end table
794
795
Some examples follow:
796
797
@example
798
# start counting PTS from zero
799
setpts=PTS-STARTPTS
800
801
# fast motion
802
setpts=0.5*PTS
803
804
# slow motion
805
setpts=2.0*PTS
806
807
# fixed rate 25 fps
808
setpts=N/(25*TB)
809
810
# fixed rate 25 fps with some jitter
811
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
812
@end example
813
814 d89e3b36 Stefano Sabatini
@section settb
815
816
Set the timebase to use for the output frames timestamps.
817
It is mainly useful for testing timebase configuration.
818
819
It accepts in input an arithmetic expression representing a rational.
820
The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
821
default timebase), and "intb" (the input timebase).
822
823
The default value for the input is "intb".
824
825
Follow some examples.
826
827
@example
828
# set the timebase to 1/25
829
settb=1/25
830
831
# set the timebase to 1/10
832
settb=0.1
833
834
#set the timebase to 1001/1000
835
settb=1+0.001
836
837
#set the timebase to 2*intb
838
settb=2*intb
839
840
#set the default timebase value
841
settb=AVTB
842
@end example
843
844 3275ac6a Stefano Sabatini
@section slicify
845
846
Pass the images of input video on to next video filter as multiple
847
slices.
848
849
@example
850
./ffmpeg -i in.avi -vf "slicify=32" out.avi
851
@end example
852
853
The filter accepts the slice height as parameter. If the parameter is
854
not specified it will use the default value of 16.
855
856
Adding this in the beginning of filter chains should make filtering
857
faster due to better use of the memory cache.
858
859 43945b27 Stefano Sabatini
@section transpose
860
861
Transpose rows with columns in the input video and optionally flip it.
862
863
It accepts a parameter representing an integer, which can assume the
864
values:
865
866
@table @samp
867
@item 0
868
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
869
@example
870
L.R     L.l
871
. . ->  . .
872
l.r     R.r
873
@end example
874
875
@item 1
876
Rotate by 90 degrees clockwise, that is:
877
@example
878
L.R     l.L
879
. . ->  . .
880
l.r     r.R
881
@end example
882
883
@item 2
884
Rotate by 90 degrees counterclockwise, that is:
885
@example
886
L.R     R.r
887
. . ->  . .
888
l.r     L.l
889
@end example
890
891
@item 3
892
Rotate by 90 degrees clockwise and vertically flip, that is:
893
@example
894
L.R     r.R
895
. . ->  . .
896
l.r     l.L
897
@end example
898
@end table
899
900 3275ac6a Stefano Sabatini
@section unsharp
901
902 843b5fd0 Stefano Sabatini
Sharpen or blur the input video.
903
904
It accepts the following parameters:
905
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
906 3275ac6a Stefano Sabatini
907
Negative values for the amount will blur the input video, while positive
908
values will sharpen. All parameters are optional and default to the
909
equivalent of the string '5:5:1.0:0:0:0.0'.
910
911
@table @option
912
913
@item luma_msize_x
914
Set the luma matrix horizontal size. It can be an integer between 3
915
and 13, default value is 5.
916
917
@item luma_msize_y
918
Set the luma matrix vertical size. It can be an integer between 3
919
and 13, default value is 5.
920
921
@item luma_amount
922
Set the luma effect strength. It can be a float number between -2.0
923
and 5.0, default value is 1.0.
924
925
@item chroma_msize_x
926
Set the chroma matrix horizontal size. It can be an integer between 3
927
and 13, default value is 0.
928
929
@item chroma_msize_y
930
Set the chroma matrix vertical size. It can be an integer between 3
931
and 13, default value is 0.
932
933
@item luma_amount
934
Set the chroma effect strength. It can be a float number between -2.0
935
and 5.0, default value is 0.0.
936
937
@end table
938
939
@example
940
# Strong luma sharpen effect parameters
941
unsharp=7:7:2.5
942
943
# Strong blur of both luma and chroma parameters
944
unsharp=7:7:-2:7:7:-2
945
946
# Use the default values with @command{ffmpeg}
947
./ffmpeg -i in.avi -vf "unsharp" out.mp4
948
@end example
949
950
@section vflip
951
952
Flip the input video vertically.
953
954
@example
955
./ffmpeg -i in.avi -vf "vflip" out.avi
956
@end example
957
958 acbac567 Michael Niedermayer
@section yadif
959
960 1653027a Stefano Sabatini
Deinterlace the input video ("yadif" means "yet another deinterlacing
961
filter").
962 acbac567 Michael Niedermayer
963 1653027a Stefano Sabatini
It accepts the optional parameters: @var{mode}:@var{parity}.
964 acbac567 Michael Niedermayer
965 1653027a Stefano Sabatini
@var{mode} specifies the interlacing mode to adopt, accepts one of the
966
following values:
967 acbac567 Michael Niedermayer
968 1653027a Stefano Sabatini
@table @option
969
@item 0
970
output 1 frame for each frame
971
@item 1
972
output 1 frame for each field
973
@item 2
974
like 0 but skips spatial interlacing check
975
@item 3
976
like 1 but skips spatial interlacing check
977
@end table
978 acbac567 Michael Niedermayer
979
Default value is 0.
980
981 1653027a Stefano Sabatini
@var{parity} specifies the picture field parity assumed for the input
982
interlaced video, accepts one of the following values:
983 acbac567 Michael Niedermayer
984 1653027a Stefano Sabatini
@table @option
985
@item 0
986
assume bottom field first
987
@item 1
988
assume top field first
989
@item -1
990
enable automatic detection
991 acbac567 Michael Niedermayer
@end table
992
993 1653027a Stefano Sabatini
Default value is -1.
994
995 3275ac6a Stefano Sabatini
@c man end VIDEO FILTERS
996
997
@chapter Video Sources
998
@c man begin VIDEO SOURCES
999
1000
Below is a description of the currently available video sources.
1001
1002 24413399 Stefano Sabatini
@section buffer
1003
1004
Buffer video frames, and make them available to the filter chain.
1005
1006
This source is mainly intended for a programmatic use, in particular
1007 ac1a31ab VĂ­ctor Paesa
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1008 24413399 Stefano Sabatini
1009
It accepts the following parameters:
1010 94498ec9 Stefano Sabatini
@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}
1011 24413399 Stefano Sabatini
1012
All the parameters need to be explicitely defined.
1013
1014
Follows the list of the accepted parameters.
1015
1016
@table @option
1017
1018
@item width, height
1019
Specify the width and height of the buffered video frames.
1020
1021
@item pix_fmt_string
1022
A string representing the pixel format of the buffered video frames.
1023
It may be a number corresponding to a pixel format, or a pixel format
1024
name.
1025
1026 94498ec9 Stefano Sabatini
@item timebase_num, timebase_den
1027
Specify numerator and denomitor of the timebase assumed by the
1028
timestamps of the buffered frames.
1029 24413399 Stefano Sabatini
@end table
1030
1031
For example:
1032
@example
1033 94498ec9 Stefano Sabatini
buffer=320:240:yuv410p:1:24
1034 24413399 Stefano Sabatini
@end example
1035
1036
will instruct the source to accept video frames with size 320x240 and
1037 94498ec9 Stefano Sabatini
with format "yuv410p" and assuming 1/24 as the timestamps timebase.
1038
Since the pixel format with name "yuv410p" corresponds to the number 6
1039
(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1040
this example corresponds to:
1041 24413399 Stefano Sabatini
@example
1042 94498ec9 Stefano Sabatini
buffer=320:240:6:1:24
1043 24413399 Stefano Sabatini
@end example
1044
1045 23ccf3c7 Stefano Sabatini
@section color
1046
1047
Provide an uniformly colored input.
1048
1049
It accepts the following parameters:
1050 b5f47309 Stefano Sabatini
@var{color}:@var{frame_size}:@var{frame_rate}
1051 23ccf3c7 Stefano Sabatini
1052
Follows the description of the accepted parameters.
1053
1054
@table @option
1055
1056
@item color
1057
Specify the color of the source. It can be the name of a color (case
1058
insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1059
alpha specifier. The default value is "black".
1060
1061
@item frame_size
1062
Specify the size of the sourced video, it may be a string of the form
1063
@var{width}x@var{heigth}, or the name of a size abbreviation. The
1064
default value is "320x240".
1065
1066
@item frame_rate
1067
Specify the frame rate of the sourced video, as the number of frames
1068
generated per second. It has to be a string in the format
1069
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1070
number or a valid video frame rate abbreviation. The default value is
1071
"25".
1072
1073
@end table
1074
1075
For example the following graph description will generate a red source
1076
with an opacity of 0.2, with size "qcif" and a frame rate of 10
1077
frames per second, which will be overlayed over the source connected
1078
to the pad with identifier "in".
1079
1080
@example
1081
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1082
@end example
1083
1084 3275ac6a Stefano Sabatini
@section nullsrc
1085
1086
Null video source, never return images. It is mainly useful as a
1087
template and to be employed in analysis / debugging tools.
1088
1089
It accepts as optional parameter a string of the form
1090 16134b7c Stefano Sabatini
@var{width}:@var{height}:@var{timebase}.
1091 3275ac6a Stefano Sabatini
1092 16134b7c Stefano Sabatini
@var{width} and @var{height} specify the size of the configured
1093
source. The default values of @var{width} and @var{height} are
1094
respectively 352 and 288 (corresponding to the CIF size format).
1095
1096
@var{timebase} specifies an arithmetic expression representing a
1097
timebase. The expression can contain the constants "PI", "E", "PHI",
1098
"AVTB" (the default timebase), and defaults to the value "AVTB".
1099 3275ac6a Stefano Sabatini
1100 f8608dca Stefano Sabatini
@section frei0r_src
1101
1102
Provide a frei0r source.
1103
1104
To enable compilation of this filter you need to install the frei0r
1105
header and configure FFmpeg with --enable-frei0r.
1106
1107
The source supports the syntax:
1108
@example
1109
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1110
@end example
1111
1112
@var{size} is the size of the video to generate, may be a string of the
1113
form @var{width}x@var{height} or a frame size abbreviation.
1114
@var{rate} is the rate of the video to generate, may be a string of
1115
the form @var{num}/@var{den} or a frame rate abbreviation.
1116
@var{src_name} is the name to the frei0r source to load. For more
1117
information regarding frei0r and how to set the parameters read the
1118
section "frei0r" (@pxref{frei0r}) in the description of the video
1119
filters.
1120
1121
Some examples follow:
1122
@example
1123
# generate a frei0r partik0l source with size 200x200 and framerate 10
1124
# which is overlayed on the overlay filter main input
1125
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1126
@end example
1127
1128 3275ac6a Stefano Sabatini
@c man end VIDEO SOURCES
1129
1130
@chapter Video Sinks
1131
@c man begin VIDEO SINKS
1132
1133
Below is a description of the currently available video sinks.
1134
1135
@section nullsink
1136
1137
Null video sink, do absolutely nothing with the input video. It is
1138
mainly useful as a template and to be employed in analysis / debugging
1139
tools.
1140
1141
@c man end VIDEO SINKS