1 @chapter Filtergraph description
2 @c man begin FILTERGRAPH DESCRIPTION
4 A filtergraph is a directed graph of connected filters. It can contain
5 cycles, and there can be multiple links between a pair of
6 filters. Each link has one input pad on one side connecting it to one
7 filter from which it takes its input, and one output pad on the other
8 side connecting it to the one filter accepting its output.
10 Each filter in a filtergraph is an instance of a filter class
11 registered in the application, which defines the features and the
12 number of input and output pads of the filter.
14 A filter with no input pads is called a "source", a filter with no
15 output pads is called a "sink".
17 @anchor{Filtergraph syntax}
18 @section Filtergraph syntax
20 A filtergraph can be represented using a textual representation, which is
21 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
22 options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
23 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
24 @file{libavfilter/avfiltergraph.h}.
26 A filterchain consists of a sequence of connected filters, each one
27 connected to the previous one in the sequence. A filterchain is
28 represented by a list of ","-separated filter descriptions.
30 A filtergraph consists of a sequence of filterchains. A sequence of
31 filterchains is represented by a list of ";"-separated filterchain
34 A filter is represented by a string of the form:
35 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
37 @var{filter_name} is the name of the filter class of which the
38 described filter is an instance of, and has to be the name of one of
39 the filter classes registered in the program.
40 The name of the filter class is optionally followed by a string
43 @var{arguments} is a string which contains the parameters used to
44 initialize the filter instance, and are described in the filter
47 The list of arguments can be quoted using the character "'" as initial
48 and ending mark, and the character '\' for escaping the characters
49 within the quoted text; otherwise the argument string is considered
50 terminated when the next special character (belonging to the set
51 "[]=;,") is encountered.
53 The name and arguments of the filter are optionally preceded and
54 followed by a list of link labels.
55 A link label allows to name a link and associate it to a filter output
56 or input pad. The preceding labels @var{in_link_1}
57 ... @var{in_link_N}, are associated to the filter input pads,
58 the following labels @var{out_link_1} ... @var{out_link_M}, are
59 associated to the output pads.
61 When two link labels with the same name are found in the
62 filtergraph, a link between the corresponding input and output pad is
65 If an output pad is not labelled, it is linked by default to the first
66 unlabelled input pad of the next filter in the filterchain.
67 For example in the filterchain:
69 nullsrc, split[L1], [L2]overlay, nullsink
71 the split filter instance has two output pads, and the overlay filter
72 instance two input pads. The first output pad of split is labelled
73 "L1", the first input pad of overlay is labelled "L2", and the second
74 output pad of split is linked to the second input pad of overlay,
75 which are both unlabelled.
77 In a complete filterchain all the unlabelled filter input and output
78 pads must be connected. A filtergraph is considered valid if all the
79 filter input and output pads of all the filterchains are connected.
81 Libavfilter will automatically insert scale filters where format
82 conversion is required. It is possible to specify swscale flags
83 for those automatically inserted scalers by prepending
84 @code{sws_flags=@var{flags};}
85 to the filtergraph description.
87 Follows a BNF description for the filtergraph syntax:
89 @var{NAME} ::= sequence of alphanumeric characters and '_'
90 @var{LINKLABEL} ::= "[" @var{NAME} "]"
91 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
92 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
93 @var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
94 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
95 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
98 @c man end FILTERGRAPH DESCRIPTION
100 @chapter Audio Filters
101 @c man begin AUDIO FILTERS
103 When you configure your Libav build, you can disable any of the
104 existing filters using --disable-filters.
105 The configure output will show the audio filters included in your
108 Below is a description of the currently available audio filters.
112 Convert the input audio to one of the specified formats. The framework will
113 negotiate the most appropriate format to minimize conversions.
115 The filter accepts the following named parameters:
119 A comma-separated list of requested sample formats.
122 A comma-separated list of requested sample rates.
124 @item channel_layouts
125 A comma-separated list of requested channel layouts.
129 If a parameter is omitted, all values are allowed.
131 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
133 aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo
138 Mixes multiple audio inputs into a single output.
142 avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
144 will mix 3 input audio streams to a single output with the same duration as the
145 first input and a dropout transition time of 3 seconds.
147 The filter accepts the following named parameters:
151 Number of inputs. If unspecified, it defaults to 2.
154 How to determine the end-of-stream.
158 Duration of longest input. (default)
161 Duration of shortest input.
164 Duration of first input.
168 @item dropout_transition
169 Transition time, in seconds, for volume renormalization when an input
170 stream ends. The default value is 2 seconds.
176 Pass the audio source unchanged to the output.
180 Show a line containing various information for each input audio frame.
181 The input audio is not modified.
183 The shown line contains a sequence of key/value pairs of the form
184 @var{key}:@var{value}.
186 A description of each shown parameter follows:
190 sequential number of the input frame, starting from 0
193 Presentation timestamp of the input frame, in time base units; the time base
194 depends on the filter input pad, and is usually 1/@var{sample_rate}.
197 presentation timestamp of the input frame in seconds
206 sample rate for the audio frame
209 number of samples (per channel) in the frame
212 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
213 the data is treated as if all the planes were concatenated.
215 @item plane_checksums
216 A list of Adler-32 checksums for each data plane.
221 Split input audio into several identical outputs.
223 The filter accepts a single parameter which specifies the number of outputs. If
224 unspecified, it defaults to 2.
228 avconv -i INPUT -filter_complex asplit=5 OUTPUT
230 will create 5 copies of the input audio.
233 Synchronize audio data with timestamps by squeezing/stretching it and/or
234 dropping samples/adding silence when needed.
236 The filter accepts the following named parameters:
240 Enable stretching/squeezing the data to make it match the timestamps. Disabled
241 by default. When disabled, time gaps are covered with silence.
244 Minimum difference between timestamps and audio data (in seconds) to trigger
245 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
246 this filter, try setting this parameter to 0.
249 Maximum compensation in samples per second. Relevant only with compensate=1.
253 Assume the first pts should be this value. The time base is 1 / sample rate.
254 This allows for padding/trimming at the start of stream. By default, no
255 assumption is made about the first frame's expected pts, so no padding or
256 trimming is done. For example, this could be set to 0 to pad the beginning with
257 silence if an audio stream starts after the video stream or to trim any samples
258 with a negative pts due to encoder delay.
262 @section channelsplit
263 Split each channel in input audio stream into a separate output stream.
265 This filter accepts the following named parameters:
268 Channel layout of the input stream. Default is "stereo".
271 For example, assuming a stereo input MP3 file
273 avconv -i in.mp3 -filter_complex channelsplit out.mkv
275 will create an output Matroska file with two audio streams, one containing only
276 the left channel and the other the right channel.
278 To split a 5.1 WAV file into per-channel files
280 avconv -i in.wav -filter_complex
281 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
282 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
283 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
288 Remap input channels to new locations.
290 This filter accepts the following named parameters:
293 Channel layout of the output stream.
296 Map channels from input to output. The argument is a comma-separated list of
297 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
298 @var{in_channel} form. @var{in_channel} can be either the name of the input
299 channel (e.g. FL for front left) or its index in the input channel layout.
300 @var{out_channel} is the name of the output channel or its index in the output
301 channel layout. If @var{out_channel} is not given then it is implicitly an
302 index, starting with zero and increasing by one for each mapping.
305 If no mapping is present, the filter will implicitly map input channels to
306 output channels preserving index.
308 For example, assuming a 5.1+downmix input MOV file
310 avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
312 will create an output WAV file tagged as stereo from the downmix channels of
315 To fix a 5.1 WAV improperly encoded in AAC's native channel order
317 avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
321 Join multiple input streams into one multi-channel stream.
323 The filter accepts the following named parameters:
327 Number of input streams. Defaults to 2.
330 Desired output channel layout. Defaults to stereo.
333 Map channels from inputs to output. The argument is a comma-separated list of
334 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
335 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
336 can be either the name of the input channel (e.g. FL for front left) or its
337 index in the specified input stream. @var{out_channel} is the name of the output
341 The filter will attempt to guess the mappings when those are not specified
342 explicitly. It does so by first trying to find an unused matching input channel
343 and if that fails it picks the first unused input channel.
345 E.g. to join 3 inputs (with properly set channel layouts)
347 avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
350 To build a 5.1 output from 6 single-channel streams:
352 avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
353 'join=inputs=6:channel_layout=5.1:map=0.0-FL\,1.0-FR\,2.0-FC\,3.0-SL\,4.0-SR\,5.0-LFE'
358 Convert the audio sample format, sample rate and channel layout. This filter is
359 not meant to be used directly, it is inserted automatically by libavfilter
360 whenever conversion is needed. Use the @var{aformat} filter to force a specific
365 Adjust the input audio volume.
367 The filter accepts the following named parameters:
371 Expresses how the audio volume will be increased or decreased.
373 Output values are clipped to the maximum value.
375 The output audio volume is given by the relation:
377 @var{output_volume} = @var{volume} * @var{input_volume}
380 Default value for @var{volume} is 1.0.
383 Mathematical precision.
385 This determines which input sample formats will be allowed, which affects the
386 precision of the volume scaling.
390 8-bit fixed-point; limits input sample format to U8, S16, and S32.
392 32-bit floating-point; limits input sample format to FLT. (default)
394 64-bit floating-point; limits input sample format to DBL.
402 Halve the input audio volume:
406 volume=volume=-6.0206dB
410 Increase input audio power by 6 decibels using fixed-point precision:
412 volume=volume=6dB:precision=fixed
416 @c man end AUDIO FILTERS
418 @chapter Audio Sources
419 @c man begin AUDIO SOURCES
421 Below is a description of the currently available audio sources.
425 Null audio source, never return audio frames. It is mainly useful as a
426 template and to be employed in analysis / debugging tools.
428 It accepts as optional parameter a string of the form
429 @var{sample_rate}:@var{channel_layout}.
431 @var{sample_rate} specify the sample rate, and defaults to 44100.
433 @var{channel_layout} specify the channel layout, and can be either an
434 integer or a string representing a channel layout. The default value
435 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
437 Check the channel_layout_map definition in
438 @file{libavutil/channel_layout.c} for the mapping between strings and
439 channel layout values.
441 Follow some examples:
443 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
451 Buffer audio frames, and make them available to the filter chain.
453 This source is not intended to be part of user-supplied graph descriptions but
454 for insertion by calling programs through the interface defined in
455 @file{libavfilter/buffersrc.h}.
457 It accepts the following named parameters:
461 Timebase which will be used for timestamps of submitted frames. It must be
462 either a floating-point number or in @var{numerator}/@var{denominator} form.
468 Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
471 Channel layout of the audio data, in the form that can be accepted by
472 @code{av_get_channel_layout()}.
475 All the parameters need to be explicitly defined.
477 @c man end AUDIO SOURCES
480 @c man begin AUDIO SINKS
482 Below is a description of the currently available audio sinks.
486 Null audio sink, do absolutely nothing with the input audio. It is
487 mainly useful as a template and to be employed in analysis / debugging
491 This sink is intended for programmatic use. Frames that arrive on this sink can
492 be retrieved by the calling program using the interface defined in
493 @file{libavfilter/buffersink.h}.
495 This filter accepts no parameters.
497 @c man end AUDIO SINKS
499 @chapter Video Filters
500 @c man begin VIDEO FILTERS
502 When you configure your Libav build, you can disable any of the
503 existing filters using --disable-filters.
504 The configure output will show the video filters included in your
507 Below is a description of the currently available video filters.
511 Detect frames that are (almost) completely black. Can be useful to
512 detect chapter transitions or commercials. Output lines consist of
513 the frame number of the detected frame, the percentage of blackness,
514 the position in the file if known or -1 and the timestamp in seconds.
516 In order to display the output lines, you need to set the loglevel at
517 least to the AV_LOG_INFO value.
519 The filter accepts the syntax:
521 blackframe[=@var{amount}:[@var{threshold}]]
524 @var{amount} is the percentage of the pixels that have to be below the
525 threshold, and defaults to 98.
527 @var{threshold} is the threshold below which a pixel value is
528 considered black, and defaults to 32.
532 Apply boxblur algorithm to the input video.
534 This filter accepts the parameters:
535 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
537 Chroma and alpha parameters are optional, if not specified they default
538 to the corresponding values set for @var{luma_radius} and
541 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
542 the radius in pixels of the box used for blurring the corresponding
543 input plane. They are expressions, and can contain the following
547 the input width and height in pixels
550 the input chroma image width and height in pixels
553 horizontal and vertical chroma subsample values. For example for the
554 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
557 The radius must be a non-negative number, and must not be greater than
558 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
559 and of @code{min(cw,ch)/2} for the chroma planes.
561 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
562 how many times the boxblur filter is applied to the corresponding
565 Some examples follow:
570 Apply a boxblur filter with luma, chroma, and alpha radius
577 Set luma radius to 2, alpha and chroma radius to 0
583 Set luma and chroma radius to a fraction of the video dimension
585 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
592 Copy the input source unchanged to the output. Mainly useful for
597 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
599 The parameters are expressions containing the following constants:
603 the corresponding mathematical approximated values for e
604 (euler number), pi (greek PI), PHI (golden ratio)
607 the computed values for @var{x} and @var{y}. They are evaluated for
611 the input width and height
614 same as @var{in_w} and @var{in_h}
617 the output (cropped) width and height
620 same as @var{out_w} and @var{out_h}
623 the number of input frame, starting from 0
626 the position in the file of the input frame, NAN if unknown
629 timestamp expressed in seconds, NAN if the input timestamp is unknown
633 The @var{out_w} and @var{out_h} parameters specify the expressions for
634 the width and height of the output (cropped) video. They are
635 evaluated just at the configuration of the filter.
637 The default value of @var{out_w} is "in_w", and the default value of
638 @var{out_h} is "in_h".
640 The expression for @var{out_w} may depend on the value of @var{out_h},
641 and the expression for @var{out_h} may depend on @var{out_w}, but they
642 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
643 evaluated after @var{out_w} and @var{out_h}.
645 The @var{x} and @var{y} parameters specify the expressions for the
646 position of the top-left corner of the output (non-cropped) area. They
647 are evaluated for each frame. If the evaluated value is not valid, it
648 is approximated to the nearest valid value.
650 The default value of @var{x} is "(in_w-out_w)/2", and the default
651 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
652 the center of the input image.
654 The expression for @var{x} may depend on @var{y}, and the expression
655 for @var{y} may depend on @var{x}.
657 Follow some examples:
659 # crop the central input area with size 100x100
662 # crop the central input area with size 2/3 of the input video
663 "crop=2/3*in_w:2/3*in_h"
665 # crop the input video central square
668 # delimit the rectangle with the top-left corner placed at position
669 # 100:100 and the right-bottom corner corresponding to the right-bottom
670 # corner of the input image.
671 crop=in_w-100:in_h-100:100:100
673 # crop 10 pixels from the left and right borders, and 20 pixels from
674 # the top and bottom borders
675 "crop=in_w-2*10:in_h-2*20"
677 # keep only the bottom right quarter of the input image
678 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
680 # crop height for getting Greek harmony
681 "crop=in_w:1/PHI*in_w"
684 "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)"
686 # erratic camera effect depending on timestamp
687 "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)"
689 # set x depending on the value of y
690 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
695 Auto-detect crop size.
697 Calculate necessary cropping parameters and prints the recommended
698 parameters through the logging system. The detected dimensions
699 correspond to the non-black area of the input video.
701 It accepts the syntax:
703 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
709 Threshold, which can be optionally specified from nothing (0) to
710 everything (255), defaults to 24.
713 Value which the width/height should be divisible by, defaults to
714 16. The offset is automatically adjusted to center the video. Use 2 to
715 get only even dimensions (needed for 4:2:2 video). 16 is best when
716 encoding to most video codecs.
719 Counter that determines after how many frames cropdetect will reset
720 the previously detected largest video area and start over to detect
721 the current optimal crop area. Defaults to 0.
723 This can be useful when channel logos distort the video area. 0
724 indicates never reset and return the largest area encountered during
730 Suppress a TV station logo by a simple interpolation of the surrounding
731 pixels. Just set a rectangle covering the logo and watch it disappear
732 (and sometimes something even uglier appear - your mileage may vary).
734 The filter accepts parameters as a string of the form
735 "@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
736 @var{key}=@var{value} pairs, separated by ":".
738 The description of the accepted parameters follows.
743 Specify the top left corner coordinates of the logo. They must be
747 Specify the width and height of the logo to clear. They must be
751 Specify the thickness of the fuzzy edge of the rectangle (added to
752 @var{w} and @var{h}). The default value is 4.
755 When set to 1, a green rectangle is drawn on the screen to simplify
756 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
757 @var{band} is set to 4. The default value is 0.
761 Some examples follow.
766 Set a rectangle covering the area with top left corner coordinates 0,0
767 and size 100x77, setting a band of size 10:
773 As the previous example, but use named options:
775 delogo=x=0:y=0:w=100:h=77:band=10
782 Draw a colored box on the input image.
784 It accepts the syntax:
786 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
792 Specify the top left corner coordinates of the box. Default to 0.
795 Specify the width and height of the box, if 0 they are interpreted as
796 the input width and height. Default to 0.
799 Specify the color of the box to write, it can be the name of a color
800 (case insensitive match) or a 0xRRGGBB[AA] sequence.
803 Follow some examples:
805 # draw a black box around the edge of the input image
808 # draw a box with color red and an opacity of 50%
809 drawbox=10:20:200:60:red@@0.5"
814 Draw text string or text from specified file on top of video using the
817 To enable compilation of this filter you need to configure Libav with
818 @code{--enable-libfreetype}.
820 The filter also recognizes strftime() sequences in the provided text
821 and expands them accordingly. Check the documentation of strftime().
823 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
826 The description of the accepted parameters follows.
831 The font file to be used for drawing text. Path must be included.
832 This parameter is mandatory.
835 The text string to be drawn. The text must be a sequence of UTF-8
837 This parameter is mandatory if no file is specified with the parameter
841 A text file containing text to be drawn. The text must be a sequence
842 of UTF-8 encoded characters.
844 This parameter is mandatory if no text string is specified with the
845 parameter @var{text}.
847 If both text and textfile are specified, an error is thrown.
850 The offsets where text will be drawn within the video frame.
851 Relative to the top/left border of the output image.
852 They accept expressions similar to the @ref{overlay} filter:
856 the computed values for @var{x} and @var{y}. They are evaluated for
860 main input width and height
863 same as @var{main_w} and @var{main_h}
866 rendered text width and height
869 same as @var{text_w} and @var{text_h}
872 the number of frames processed, starting from 0
875 timestamp expressed in seconds, NAN if the input timestamp is unknown
879 The default value of @var{x} and @var{y} is 0.
882 The font size to be used for drawing text.
883 The default value of @var{fontsize} is 16.
886 The color to be used for drawing fonts.
887 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
888 (e.g. "0xff000033"), possibly followed by an alpha specifier.
889 The default value of @var{fontcolor} is "black".
892 The color to be used for drawing box around text.
893 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
894 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
895 The default value of @var{boxcolor} is "white".
898 Used to draw a box around text using background color.
899 Value should be either 1 (enable) or 0 (disable).
900 The default value of @var{box} is 0.
902 @item shadowx, shadowy
903 The x and y offsets for the text shadow position with respect to the
904 position of the text. They can be either positive or negative
905 values. Default value for both is "0".
908 The color to be used for drawing a shadow behind the drawn text. It
909 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
910 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
911 The default value of @var{shadowcolor} is "black".
914 Flags to be used for loading the fonts.
916 The flags map the corresponding flags supported by libfreetype, and are
917 a combination of the following values:
924 @item vertical_layout
928 @item ignore_global_advance_width
930 @item ignore_transform
937 Default value is "render".
939 For more information consult the documentation for the FT_LOAD_*
943 The size in number of spaces to use for rendering the tab.
947 If true, check and fix text coords to avoid clipping.
950 For example the command:
952 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
955 will draw "Test Text" with font FreeSerif, using the default values
956 for the optional parameters.
960 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
961 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
964 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
965 and y=50 (counting from the top-left corner of the screen), text is
966 yellow with a red box around it. Both the text and the box have an
969 Note that the double quotes are not necessary if spaces are not used
970 within the parameter list.
972 For more information about libfreetype, check:
973 @url{http://www.freetype.org/}.
977 Apply fade-in/out effect to input video.
979 It accepts the parameters:
980 @var{type}:@var{start_frame}:@var{nb_frames}
982 @var{type} specifies if the effect type, can be either "in" for
983 fade-in, or "out" for a fade-out effect.
985 @var{start_frame} specifies the number of the start frame for starting
986 to apply the fade effect.
988 @var{nb_frames} specifies the number of frames for which the fade
989 effect has to last. At the end of the fade-in effect the output video
990 will have the same intensity as the input video, at the end of the
991 fade-out transition the output video will be completely black.
993 A few usage examples follow, usable too as test scenarios.
995 # fade in first 30 frames of video
998 # fade out last 45 frames of a 200-frame video
1001 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
1002 fade=in:0:25, fade=out:975:25
1004 # make first 5 frames black, then fade in from frame 5-24
1010 Transform the field order of the input video.
1012 It accepts one parameter which specifies the required field order that
1013 the input interlaced video will be transformed to. The parameter can
1014 assume one of the following values:
1018 output bottom field first
1020 output top field first
1023 Default value is "tff".
1025 Transformation is achieved by shifting the picture content up or down
1026 by one line, and filling the remaining line with appropriate picture content.
1027 This method is consistent with most broadcast field order converters.
1029 If the input video is not flagged as being interlaced, or it is already
1030 flagged as being of the required output field order then this filter does
1031 not alter the incoming video.
1033 This filter is very useful when converting to or from PAL DV material,
1034 which is bottom field first.
1038 ./avconv -i in.vob -vf "fieldorder=bff" out.dv
1043 Buffer input images and send them when they are requested.
1045 This filter is mainly useful when auto-inserted by the libavfilter
1048 The filter does not take parameters.
1052 Convert the input video to one of the specified pixel formats.
1053 Libavfilter will try to pick one that is supported for the input to
1056 The filter accepts a list of pixel format names, separated by ":",
1057 for example "yuv420p:monow:rgb24".
1059 Some examples follow:
1061 # convert the input video to the format "yuv420p"
1064 # convert the input video to any of the formats in the list
1065 format=yuv420p:yuv444p:yuv410p
1070 Convert the video to specified constant framerate by duplicating or dropping
1071 frames as necessary.
1073 This filter accepts the following named parameters:
1077 Desired output framerate.
1084 Apply a frei0r effect to the input video.
1086 To enable compilation of this filter you need to install the frei0r
1087 header and configure Libav with --enable-frei0r.
1089 The filter supports the syntax:
1091 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
1094 @var{filter_name} is the name to the frei0r effect to load. If the
1095 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
1096 is searched in each one of the directories specified by the colon
1097 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
1098 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
1099 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
1101 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
1102 for the frei0r effect.
1104 A frei0r effect parameter can be a boolean (whose values are specified
1105 with "y" and "n"), a double, a color (specified by the syntax
1106 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
1107 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
1108 description), a position (specified by the syntax @var{X}/@var{Y},
1109 @var{X} and @var{Y} being float numbers) and a string.
1111 The number and kind of parameters depend on the loaded effect. If an
1112 effect parameter is not specified the default value is set.
1114 Some examples follow:
1116 # apply the distort0r effect, set the first two double parameters
1117 frei0r=distort0r:0.5:0.01
1119 # apply the colordistance effect, takes a color as first parameter
1120 frei0r=colordistance:0.2/0.3/0.4
1121 frei0r=colordistance:violet
1122 frei0r=colordistance:0x112233
1124 # apply the perspective effect, specify the top left and top right
1126 frei0r=perspective:0.2/0.2:0.8/0.2
1129 For more information see:
1130 @url{http://piksel.org/frei0r}
1134 Fix the banding artifacts that are sometimes introduced into nearly flat
1135 regions by truncation to 8bit colordepth.
1136 Interpolate the gradients that should go where the bands are, and
1139 This filter is designed for playback only. Do not use it prior to
1140 lossy compression, because compression tends to lose the dither and
1141 bring back the bands.
1143 The filter takes two optional parameters, separated by ':':
1144 @var{strength}:@var{radius}
1146 @var{strength} is the maximum amount by which the filter will change
1147 any one pixel. Also the threshold for detecting nearly flat
1148 regions. Acceptable values range from .51 to 255, default value is
1149 1.2, out-of-range values will be clipped to the valid range.
1151 @var{radius} is the neighborhood to fit the gradient to. A larger
1152 radius makes for smoother gradients, but also prevents the filter from
1153 modifying the pixels near detailed regions. Acceptable values are
1154 8-32, default value is 16, out-of-range values will be clipped to the
1158 # default parameters
1167 Flip the input video horizontally.
1169 For example to horizontally flip the input video with @command{avconv}:
1171 avconv -i in.avi -vf "hflip" out.avi
1176 High precision/quality 3d denoise filter. This filter aims to reduce
1177 image noise producing smooth images and making still images really
1178 still. It should enhance compressibility.
1180 It accepts the following optional parameters:
1181 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
1185 a non-negative float number which specifies spatial luma strength,
1188 @item chroma_spatial
1189 a non-negative float number which specifies spatial chroma strength,
1190 defaults to 3.0*@var{luma_spatial}/4.0
1193 a float number which specifies luma temporal strength, defaults to
1194 6.0*@var{luma_spatial}/4.0
1197 a float number which specifies chroma temporal strength, defaults to
1198 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
1201 @section lut, lutrgb, lutyuv
1203 Compute a look-up table for binding each pixel component input value
1204 to an output value, and apply it to input video.
1206 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
1207 to an RGB input video.
1209 These filters accept in input a ":"-separated list of options, which
1210 specify the expressions used for computing the lookup table for the
1211 corresponding pixel component values.
1213 The @var{lut} filter requires either YUV or RGB pixel formats in
1214 input, and accepts the options:
1216 @item @var{c0} (first pixel component)
1217 @item @var{c1} (second pixel component)
1218 @item @var{c2} (third pixel component)
1219 @item @var{c3} (fourth pixel component, corresponds to the alpha component)
1222 The exact component associated to each option depends on the format in
1225 The @var{lutrgb} filter requires RGB pixel formats in input, and
1226 accepts the options:
1228 @item @var{r} (red component)
1229 @item @var{g} (green component)
1230 @item @var{b} (blue component)
1231 @item @var{a} (alpha component)
1234 The @var{lutyuv} filter requires YUV pixel formats in input, and
1235 accepts the options:
1237 @item @var{y} (Y/luminance component)
1238 @item @var{u} (U/Cb component)
1239 @item @var{v} (V/Cr component)
1240 @item @var{a} (alpha component)
1243 The expressions can contain the following constants and functions:
1247 the corresponding mathematical approximated values for e
1248 (euler number), pi (greek PI), PHI (golden ratio)
1251 the input width and height
1254 input value for the pixel component
1257 the input value clipped in the @var{minval}-@var{maxval} range
1260 maximum value for the pixel component
1263 minimum value for the pixel component
1266 the negated value for the pixel component value clipped in the
1267 @var{minval}-@var{maxval} range , it corresponds to the expression
1268 "maxval-clipval+minval"
1271 the computed value in @var{val} clipped in the
1272 @var{minval}-@var{maxval} range
1274 @item gammaval(gamma)
1275 the computed gamma correction value of the pixel component value
1276 clipped in the @var{minval}-@var{maxval} range, corresponds to the
1278 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
1282 All expressions default to "val".
1284 Some examples follow:
1286 # negate input video
1287 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
1288 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
1290 # the above is the same as
1291 lutrgb="r=negval:g=negval:b=negval"
1292 lutyuv="y=negval:u=negval:v=negval"
1297 # remove chroma components, turns the video into a graytone image
1298 lutyuv="u=128:v=128"
1300 # apply a luma burning effect
1303 # remove green and blue components
1306 # set a constant alpha channel value on input
1307 format=rgba,lutrgb=a="maxval-minval/2"
1309 # correct luminance gamma by a 0.5 factor
1310 lutyuv=y=gammaval(0.5)
1317 This filter accepts an integer in input, if non-zero it negates the
1318 alpha component (if available). The default value in input is 0.
1320 Force libavfilter not to use any of the specified pixel formats for the
1321 input to the next filter.
1323 The filter accepts a list of pixel format names, separated by ":",
1324 for example "yuv420p:monow:rgb24".
1326 Some examples follow:
1328 # force libavfilter to use a format different from "yuv420p" for the
1329 # input to the vflip filter
1330 noformat=yuv420p,vflip
1332 # convert the input video to any of the formats not contained in the list
1333 noformat=yuv420p:yuv444p:yuv410p
1338 Pass the video source unchanged to the output.
1342 Apply video transform using libopencv.
1344 To enable this filter install libopencv library and headers and
1345 configure Libav with --enable-libopencv.
1347 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1349 @var{filter_name} is the name of the libopencv filter to apply.
1351 @var{filter_params} specifies the parameters to pass to the libopencv
1352 filter. If not specified the default values are assumed.
1354 Refer to the official libopencv documentation for more precise
1356 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1358 Follows the list of supported libopencv filters.
1363 Dilate an image by using a specific structuring element.
1364 This filter corresponds to the libopencv function @code{cvDilate}.
1366 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1368 @var{struct_el} represents a structuring element, and has the syntax:
1369 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1371 @var{cols} and @var{rows} represent the number of columns and rows of
1372 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1373 point, and @var{shape} the shape for the structuring element, and
1374 can be one of the values "rect", "cross", "ellipse", "custom".
1376 If the value for @var{shape} is "custom", it must be followed by a
1377 string of the form "=@var{filename}". The file with name
1378 @var{filename} is assumed to represent a binary image, with each
1379 printable character corresponding to a bright pixel. When a custom
1380 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1381 or columns and rows of the read file are assumed instead.
1383 The default value for @var{struct_el} is "3x3+0x0/rect".
1385 @var{nb_iterations} specifies the number of times the transform is
1386 applied to the image, and defaults to 1.
1388 Follow some example:
1390 # use the default values
1393 # dilate using a structuring element with a 5x5 cross, iterate two times
1394 ocv=dilate=5x5+2x2/cross:2
1396 # read the shape from the file diamond.shape, iterate two times
1397 # the file diamond.shape may contain a pattern of characters like this:
1403 # the specified cols and rows are ignored (but not the anchor point coordinates)
1404 ocv=0x0+2x2/custom=diamond.shape:2
1409 Erode an image by using a specific structuring element.
1410 This filter corresponds to the libopencv function @code{cvErode}.
1412 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1413 with the same syntax and semantics as the @ref{dilate} filter.
1417 Smooth the input video.
1419 The filter takes the following parameters:
1420 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1422 @var{type} is the type of smooth filter to apply, and can be one of
1423 the following values: "blur", "blur_no_scale", "median", "gaussian",
1424 "bilateral". The default value is "gaussian".
1426 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1427 parameters whose meanings depend on smooth type. @var{param1} and
1428 @var{param2} accept integer positive values or 0, @var{param3} and
1429 @var{param4} accept float values.
1431 The default value for @var{param1} is 3, the default value for the
1432 other parameters is 0.
1434 These parameters correspond to the parameters assigned to the
1435 libopencv function @code{cvSmooth}.
1440 Overlay one video on top of another.
1442 It takes two inputs and one output, the first input is the "main"
1443 video on which the second input is overlayed.
1445 It accepts the parameters: @var{x}:@var{y}.
1447 @var{x} is the x coordinate of the overlayed video on the main video,
1448 @var{y} is the y coordinate. The parameters are expressions containing
1449 the following parameters:
1452 @item main_w, main_h
1453 main input width and height
1456 same as @var{main_w} and @var{main_h}
1458 @item overlay_w, overlay_h
1459 overlay input width and height
1462 same as @var{overlay_w} and @var{overlay_h}
1465 Be aware that frames are taken from each input video in timestamp
1466 order, hence, if their initial timestamps differ, it is a a good idea
1467 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1468 have them begin in the same zero timestamp, as it does the example for
1469 the @var{movie} filter.
1471 Follow some examples:
1473 # draw the overlay at 10 pixels from the bottom right
1474 # corner of the main video.
1475 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1477 # insert a transparent PNG logo in the bottom left corner of the input
1478 avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
1480 # insert 2 different transparent PNG logos (second logo on bottom
1482 avconv -i input -i logo1 -i logo2 -filter_complex
1483 'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
1485 # add a transparent color layer on top of the main video,
1486 # WxH specifies the size of the main input to the overlay filter
1487 color=red@.3:WxH [over]; [in][over] overlay [out]
1490 You can chain together more overlays but the efficiency of such
1491 approach is yet to be tested.
1495 Add paddings to the input image, and places the original input at the
1496 given coordinates @var{x}, @var{y}.
1498 It accepts the following parameters:
1499 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1501 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1502 expressions containing the following constants:
1506 the corresponding mathematical approximated values for e
1507 (euler number), pi (greek PI), phi (golden ratio)
1510 the input video width and height
1513 same as @var{in_w} and @var{in_h}
1516 the output width and height, that is the size of the padded area as
1517 specified by the @var{width} and @var{height} expressions
1520 same as @var{out_w} and @var{out_h}
1523 x and y offsets as specified by the @var{x} and @var{y}
1524 expressions, or NAN if not yet specified
1527 input display aspect ratio, same as @var{iw} / @var{ih}
1530 horizontal and vertical chroma subsample values. For example for the
1531 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1534 Follows the description of the accepted parameters.
1539 Specify the size of the output image with the paddings added. If the
1540 value for @var{width} or @var{height} is 0, the corresponding input size
1541 is used for the output.
1543 The @var{width} expression can reference the value set by the
1544 @var{height} expression, and vice versa.
1546 The default value of @var{width} and @var{height} is 0.
1550 Specify the offsets where to place the input image in the padded area
1551 with respect to the top/left border of the output image.
1553 The @var{x} expression can reference the value set by the @var{y}
1554 expression, and vice versa.
1556 The default value of @var{x} and @var{y} is 0.
1560 Specify the color of the padded area, it can be the name of a color
1561 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1563 The default value of @var{color} is "black".
1567 Some examples follow:
1570 # Add paddings with color "violet" to the input video. Output video
1571 # size is 640x480, the top-left corner of the input video is placed at
1573 pad=640:480:0:40:violet
1575 # pad the input to get an output with dimensions increased bt 3/2,
1576 # and put the input video at the center of the padded area
1577 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1579 # pad the input to get a squared output with size equal to the maximum
1580 # value between the input width and height, and put the input video at
1581 # the center of the padded area
1582 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1584 # pad the input to get a final w/h ratio of 16:9
1585 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1587 # double output size and put the input video in the bottom-right
1588 # corner of the output padded area
1589 pad="2*iw:2*ih:ow-iw:oh-ih"
1592 @section pixdesctest
1594 Pixel format descriptor test filter, mainly useful for internal
1595 testing. The output video should be equal to the input video.
1599 format=monow, pixdesctest
1602 can be used to test the monowhite pixel format descriptor definition.
1606 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1608 The parameters @var{width} and @var{height} are expressions containing
1609 the following constants:
1613 the corresponding mathematical approximated values for e
1614 (euler number), pi (greek PI), phi (golden ratio)
1617 the input width and height
1620 same as @var{in_w} and @var{in_h}
1623 the output (cropped) width and height
1626 same as @var{out_w} and @var{out_h}
1629 input display aspect ratio, same as @var{iw} / @var{ih}
1632 input sample aspect ratio
1635 horizontal and vertical chroma subsample values. For example for the
1636 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1639 If the input image format is different from the format requested by
1640 the next filter, the scale filter will convert the input to the
1643 If the value for @var{width} or @var{height} is 0, the respective input
1644 size is used for the output.
1646 If the value for @var{width} or @var{height} is -1, the scale filter will
1647 use, for the respective output size, a value that maintains the aspect
1648 ratio of the input image.
1650 The default value of @var{width} and @var{height} is 0.
1652 Some examples follow:
1654 # scale the input video to a size of 200x100.
1657 # scale the input to 2x
1659 # the above is the same as
1662 # scale the input to half size
1665 # increase the width, and set the height to the same size
1668 # seek for Greek harmony
1672 # increase the height, and set the width to 3/2 of the height
1675 # increase the size, but make the size a multiple of the chroma
1676 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1678 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1679 scale='min(500\, iw*3/2):-1'
1683 Select frames to pass in output.
1685 It accepts in input an expression, which is evaluated for each input
1686 frame. If the expression is evaluated to a non-zero value, the frame
1687 is selected and passed to the output, otherwise it is discarded.
1689 The expression can contain the following constants:
1702 the sequential number of the filtered frame, starting from 0
1705 the sequential number of the selected frame, starting from 0
1707 @item prev_selected_n
1708 the sequential number of the last selected frame, NAN if undefined
1711 timebase of the input timestamps
1714 the PTS (Presentation TimeStamp) of the filtered video frame,
1715 expressed in @var{TB} units, NAN if undefined
1718 the PTS (Presentation TimeStamp) of the filtered video frame,
1719 expressed in seconds, NAN if undefined
1722 the PTS of the previously filtered video frame, NAN if undefined
1724 @item prev_selected_pts
1725 the PTS of the last previously filtered video frame, NAN if undefined
1727 @item prev_selected_t
1728 the PTS of the last previously selected video frame, NAN if undefined
1731 the PTS of the first video frame in the video, NAN if undefined
1734 the time of the first video frame in the video, NAN if undefined
1737 the type of the filtered frame, can assume one of the following
1749 @item interlace_type
1750 the frame interlace type, can assume one of the following values:
1753 the frame is progressive (not interlaced)
1755 the frame is top-field-first
1757 the frame is bottom-field-first
1761 1 if the filtered frame is a key-frame, 0 otherwise
1764 the position in the file of the filtered frame, -1 if the information
1765 is not available (e.g. for synthetic video)
1768 The default value of the select expression is "1".
1770 Some examples follow:
1773 # select all frames in input
1776 # the above is the same as:
1782 # select only I-frames
1783 select='eq(pict_type\,I)'
1785 # select one frame every 100
1786 select='not(mod(n\,100))'
1788 # select only frames contained in the 10-20 time interval
1789 select='gte(t\,10)*lte(t\,20)'
1791 # select only I frames contained in the 10-20 time interval
1792 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1794 # select frames with a minimum distance of 10 seconds
1795 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1801 Set the Display Aspect Ratio for the filter output video.
1803 This is done by changing the specified Sample (aka Pixel) Aspect
1804 Ratio, according to the following equation:
1805 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1807 Keep in mind that this filter does not modify the pixel dimensions of
1808 the video frame. Also the display aspect ratio set by this filter may
1809 be changed by later filters in the filterchain, e.g. in case of
1810 scaling or if another "setdar" or a "setsar" filter is applied.
1812 The filter accepts a parameter string which represents the wanted
1813 display aspect ratio.
1814 The parameter can be a floating point number string, or an expression
1815 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1816 numerator and denominator of the aspect ratio.
1817 If the parameter is not specified, it is assumed the value "0:1".
1819 For example to change the display aspect ratio to 16:9, specify:
1822 # the above is equivalent to
1826 See also the @ref{setsar} filter documentation.
1830 Change the PTS (presentation timestamp) of the input video frames.
1832 Accept in input an expression evaluated through the eval API, which
1833 can contain the following constants:
1837 the presentation timestamp in input
1849 the count of the input frame, starting from 0.
1852 the PTS of the first video frame
1855 tell if the current frame is interlaced
1858 original position in the file of the frame, or undefined if undefined
1859 for the current frame
1869 Some examples follow:
1872 # start counting PTS from zero
1884 # fixed rate 25 fps with some jitter
1885 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1891 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1893 Note that as a consequence of the application of this filter, the
1894 output display aspect ratio will change according to the following
1896 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1898 Keep in mind that the sample aspect ratio set by this filter may be
1899 changed by later filters in the filterchain, e.g. if another "setsar"
1900 or a "setdar" filter is applied.
1902 The filter accepts a parameter string which represents the wanted
1903 sample aspect ratio.
1904 The parameter can be a floating point number string, or an expression
1905 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1906 numerator and denominator of the aspect ratio.
1907 If the parameter is not specified, it is assumed the value "0:1".
1909 For example to change the sample aspect ratio to 10:11, specify:
1916 Set the timebase to use for the output frames timestamps.
1917 It is mainly useful for testing timebase configuration.
1919 It accepts in input an arithmetic expression representing a rational.
1920 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1921 default timebase), and "intb" (the input timebase).
1923 The default value for the input is "intb".
1925 Follow some examples.
1928 # set the timebase to 1/25
1931 # set the timebase to 1/10
1934 #set the timebase to 1001/1000
1937 #set the timebase to 2*intb
1940 #set the default timebase value
1946 Show a line containing various information for each input video frame.
1947 The input video is not modified.
1949 The shown line contains a sequence of key/value pairs of the form
1950 @var{key}:@var{value}.
1952 A description of each shown parameter follows:
1956 sequential number of the input frame, starting from 0
1959 Presentation TimeStamp of the input frame, expressed as a number of
1960 time base units. The time base unit depends on the filter input pad.
1963 Presentation TimeStamp of the input frame, expressed as a number of
1967 position of the frame in the input stream, -1 if this information in
1968 unavailable and/or meaningless (for example in case of synthetic video)
1974 sample aspect ratio of the input frame, expressed in the form
1978 size of the input frame, expressed in the form
1979 @var{width}x@var{height}
1982 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1983 for bottom field first)
1986 1 if the frame is a key frame, 0 otherwise
1989 picture type of the input frame ("I" for an I-frame, "P" for a
1990 P-frame, "B" for a B-frame, "?" for unknown type).
1991 Check also the documentation of the @code{AVPictureType} enum and of
1992 the @code{av_get_picture_type_char} function defined in
1993 @file{libavutil/avutil.h}.
1996 Adler-32 checksum of all the planes of the input frame
1998 @item plane_checksum
1999 Adler-32 checksum of each plane of the input frame, expressed in the form
2000 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
2005 Split input video into several identical outputs.
2007 The filter accepts a single parameter which specifies the number of outputs. If
2008 unspecified, it defaults to 2.
2012 avconv -i INPUT -filter_complex split=5 OUTPUT
2014 will create 5 copies of the input video.
2018 Transpose rows with columns in the input video and optionally flip it.
2020 It accepts a parameter representing an integer, which can assume the
2025 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
2033 Rotate by 90 degrees clockwise, that is:
2041 Rotate by 90 degrees counterclockwise, that is:
2049 Rotate by 90 degrees clockwise and vertically flip, that is:
2059 Sharpen or blur the input video.
2061 It accepts the following parameters:
2062 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
2064 Negative values for the amount will blur the input video, while positive
2065 values will sharpen. All parameters are optional and default to the
2066 equivalent of the string '5:5:1.0:5:5:0.0'.
2071 Set the luma matrix horizontal size. It can be an integer between 3
2072 and 13, default value is 5.
2075 Set the luma matrix vertical size. It can be an integer between 3
2076 and 13, default value is 5.
2079 Set the luma effect strength. It can be a float number between -2.0
2080 and 5.0, default value is 1.0.
2082 @item chroma_msize_x
2083 Set the chroma matrix horizontal size. It can be an integer between 3
2084 and 13, default value is 5.
2086 @item chroma_msize_y
2087 Set the chroma matrix vertical size. It can be an integer between 3
2088 and 13, default value is 5.
2091 Set the chroma effect strength. It can be a float number between -2.0
2092 and 5.0, default value is 0.0.
2097 # Strong luma sharpen effect parameters
2100 # Strong blur of both luma and chroma parameters
2101 unsharp=7:7:-2:7:7:-2
2103 # Use the default values with @command{avconv}
2104 ./avconv -i in.avi -vf "unsharp" out.mp4
2109 Flip the input video vertically.
2112 ./avconv -i in.avi -vf "vflip" out.avi
2117 Deinterlace the input video ("yadif" means "yet another deinterlacing
2120 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
2122 @var{mode} specifies the interlacing mode to adopt, accepts one of the
2127 output 1 frame for each frame
2129 output 1 frame for each field
2131 like 0 but skips spatial interlacing check
2133 like 1 but skips spatial interlacing check
2138 @var{parity} specifies the picture field parity assumed for the input
2139 interlaced video, accepts one of the following values:
2143 assume top field first
2145 assume bottom field first
2147 enable automatic detection
2150 Default value is -1.
2151 If interlacing is unknown or decoder does not export this information,
2152 top field first will be assumed.
2154 @var{auto} specifies if deinterlacer should trust the interlaced flag
2155 and only deinterlace frames marked as interlaced
2159 deinterlace all frames
2161 only deinterlace frames marked as interlaced
2166 @c man end VIDEO FILTERS
2168 @chapter Video Sources
2169 @c man begin VIDEO SOURCES
2171 Below is a description of the currently available video sources.
2175 Buffer video frames, and make them available to the filter chain.
2177 This source is mainly intended for a programmatic use, in particular
2178 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
2180 It accepts the following parameters:
2181 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
2183 All the parameters need to be explicitly defined.
2185 Follows the list of the accepted parameters.
2190 Specify the width and height of the buffered video frames.
2192 @item pix_fmt_string
2193 A string representing the pixel format of the buffered video frames.
2194 It may be a number corresponding to a pixel format, or a pixel format
2197 @item timebase_num, timebase_den
2198 Specify numerator and denomitor of the timebase assumed by the
2199 timestamps of the buffered frames.
2201 @item sample_aspect_ratio.num, sample_aspect_ratio.den
2202 Specify numerator and denominator of the sample aspect ratio assumed
2203 by the video frames.
2208 buffer=320:240:yuv410p:1:24:1:1
2211 will instruct the source to accept video frames with size 320x240 and
2212 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2213 square pixels (1:1 sample aspect ratio).
2214 Since the pixel format with name "yuv410p" corresponds to the number 6
2215 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
2216 this example corresponds to:
2218 buffer=320:240:6:1:24
2223 Provide an uniformly colored input.
2225 It accepts the following parameters:
2226 @var{color}:@var{frame_size}:@var{frame_rate}
2228 Follows the description of the accepted parameters.
2233 Specify the color of the source. It can be the name of a color (case
2234 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2235 alpha specifier. The default value is "black".
2238 Specify the size of the sourced video, it may be a string of the form
2239 @var{width}x@var{height}, or the name of a size abbreviation. The
2240 default value is "320x240".
2243 Specify the frame rate of the sourced video, as the number of frames
2244 generated per second. It has to be a string in the format
2245 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2246 number or a valid video frame rate abbreviation. The default value is
2251 For example the following graph description will generate a red source
2252 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2253 frames per second, which will be overlayed over the source connected
2254 to the pad with identifier "in".
2257 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2262 Read a video stream from a movie container.
2264 Note that this source is a hack that bypasses the standard input path. It can be
2265 useful in applications that do not support arbitrary filter graphs, but its use
2266 is discouraged in those that do. Specifically in @command{avconv} this filter
2267 should never be used, the @option{-filter_complex} option fully replaces it.
2269 It accepts the syntax: @var{movie_name}[:@var{options}] where
2270 @var{movie_name} is the name of the resource to read (not necessarily
2271 a file but also a device or a stream accessed through some protocol),
2272 and @var{options} is an optional sequence of @var{key}=@var{value}
2273 pairs, separated by ":".
2275 The description of the accepted options follows.
2279 @item format_name, f
2280 Specifies the format assumed for the movie to read, and can be either
2281 the name of a container or an input device. If not specified the
2282 format is guessed from @var{movie_name} or by probing.
2284 @item seek_point, sp
2285 Specifies the seek point in seconds, the frames will be output
2286 starting from this seek point, the parameter is evaluated with
2287 @code{av_strtod} so the numerical value may be suffixed by an IS
2288 postfix. Default value is "0".
2290 @item stream_index, si
2291 Specifies the index of the video stream to read. If the value is -1,
2292 the best suited video stream will be automatically selected. Default
2297 This filter allows to overlay a second video on top of main input of
2298 a filtergraph as shown in this graph:
2300 input -----------> deltapts0 --> overlay --> output
2303 movie --> scale--> deltapts1 -------+
2306 Some examples follow:
2308 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2309 # on top of the input labelled as "in".
2310 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2311 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2313 # read from a video4linux2 device, and overlay it on top of the input
2315 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2316 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2322 Null video source, never return images. It is mainly useful as a
2323 template and to be employed in analysis / debugging tools.
2325 It accepts as optional parameter a string of the form
2326 @var{width}:@var{height}:@var{timebase}.
2328 @var{width} and @var{height} specify the size of the configured
2329 source. The default values of @var{width} and @var{height} are
2330 respectively 352 and 288 (corresponding to the CIF size format).
2332 @var{timebase} specifies an arithmetic expression representing a
2333 timebase. The expression can contain the constants "PI", "E", "PHI",
2334 "AVTB" (the default timebase), and defaults to the value "AVTB".
2338 Provide a frei0r source.
2340 To enable compilation of this filter you need to install the frei0r
2341 header and configure Libav with --enable-frei0r.
2343 The source supports the syntax:
2345 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2348 @var{size} is the size of the video to generate, may be a string of the
2349 form @var{width}x@var{height} or a frame size abbreviation.
2350 @var{rate} is the rate of the video to generate, may be a string of
2351 the form @var{num}/@var{den} or a frame rate abbreviation.
2352 @var{src_name} is the name to the frei0r source to load. For more
2353 information regarding frei0r and how to set the parameters read the
2354 section @ref{frei0r} in the description of the video filters.
2356 Some examples follow:
2358 # generate a frei0r partik0l source with size 200x200 and framerate 10
2359 # which is overlayed on the overlay filter main input
2360 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2363 @section rgbtestsrc, testsrc
2365 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2366 detecting RGB vs BGR issues. You should see a red, green and blue
2367 stripe from top to bottom.
2369 The @code{testsrc} source generates a test video pattern, showing a
2370 color pattern, a scrolling gradient and a timestamp. This is mainly
2371 intended for testing purposes.
2373 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2374 separated by ":". The description of the accepted options follows.
2379 Specify the size of the sourced video, it may be a string of the form
2380 @var{width}x@var{height}, or the name of a size abbreviation. The
2381 default value is "320x240".
2384 Specify the frame rate of the sourced video, as the number of frames
2385 generated per second. It has to be a string in the format
2386 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2387 number or a valid video frame rate abbreviation. The default value is
2391 Set the sample aspect ratio of the sourced video.
2394 Set the video duration of the sourced video. The accepted syntax is:
2396 [-]HH[:MM[:SS[.m...]]]
2399 See also the function @code{av_parse_time()}.
2401 If not specified, or the expressed duration is negative, the video is
2402 supposed to be generated forever.
2405 For example the following:
2407 testsrc=duration=5.3:size=qcif:rate=10
2410 will generate a video with a duration of 5.3 seconds, with size
2411 176x144 and a framerate of 10 frames per second.
2413 @c man end VIDEO SOURCES
2415 @chapter Video Sinks
2416 @c man begin VIDEO SINKS
2418 Below is a description of the currently available video sinks.
2422 Buffer video frames, and make them available to the end of the filter
2425 This sink is intended for a programmatic use through the interface defined in
2426 @file{libavfilter/buffersink.h}.
2430 Null video sink, do absolutely nothing with the input video. It is
2431 mainly useful as a template and to be employed in analysis / debugging
2434 @c man end VIDEO SINKS