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.
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.
261 @section channelsplit
262 Split each channel in input audio stream into a separate output stream.
264 This filter accepts the following named parameters:
267 Channel layout of the input stream. Default is "stereo".
270 For example, assuming a stereo input MP3 file
272 avconv -i in.mp3 -filter_complex channelsplit out.mkv
274 will create an output Matroska file with two audio streams, one containing only
275 the left channel and the other the right channel.
277 To split a 5.1 WAV file into per-channel files
279 avconv -i in.wav -filter_complex
280 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
281 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
282 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
287 Remap input channels to new locations.
289 This filter accepts the following named parameters:
292 Channel layout of the output stream.
295 Map channels from input to output. The argument is a comma-separated list of
296 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
297 @var{in_channel} form. @var{in_channel} can be either the name of the input
298 channel (e.g. FL for front left) or its index in the input channel layout.
299 @var{out_channel} is the name of the output channel or its index in the output
300 channel layout. If @var{out_channel} is not given then it is implicitly an
301 index, starting with zero and increasing by one for each mapping.
304 If no mapping is present, the filter will implicitly map input channels to
305 output channels preserving index.
307 For example, assuming a 5.1+downmix input MOV file
309 avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
311 will create an output WAV file tagged as stereo from the downmix channels of
314 To fix a 5.1 WAV improperly encoded in AAC's native channel order
316 avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
320 Join multiple input streams into one multi-channel stream.
322 The filter accepts the following named parameters:
326 Number of input streams. Defaults to 2.
329 Desired output channel layout. Defaults to stereo.
332 Map channels from inputs to output. The argument is a comma-separated list of
333 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
334 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
335 can be either the name of the input channel (e.g. FL for front left) or its
336 index in the specified input stream. @var{out_channel} is the name of the output
340 The filter will attempt to guess the mappings when those are not specified
341 explicitly. It does so by first trying to find an unused matching input channel
342 and if that fails it picks the first unused input channel.
344 E.g. to join 3 inputs (with properly set channel layouts)
346 avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
349 To build a 5.1 output from 6 single-channel streams:
351 avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
352 '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'
357 Convert the audio sample format, sample rate and channel layout. This filter is
358 not meant to be used directly, it is inserted automatically by libavfilter
359 whenever conversion is needed. Use the @var{aformat} filter to force a specific
364 Adjust the input audio volume.
366 The filter accepts the following named parameters:
370 Expresses how the audio volume will be increased or decreased.
372 Output values are clipped to the maximum value.
374 The output audio volume is given by the relation:
376 @var{output_volume} = @var{volume} * @var{input_volume}
379 Default value for @var{volume} is 1.0.
382 Mathematical precision.
384 This determines which input sample formats will be allowed, which affects the
385 precision of the volume scaling.
389 8-bit fixed-point; limits input sample format to U8, S16, and S32.
391 32-bit floating-point; limits input sample format to FLT. (default)
393 64-bit floating-point; limits input sample format to DBL.
401 Halve the input audio volume:
405 volume=volume=-6.0206dB
409 Increase input audio power by 6 decibels using fixed-point precision:
411 volume=volume=6dB:precision=fixed
415 @c man end AUDIO FILTERS
417 @chapter Audio Sources
418 @c man begin AUDIO SOURCES
420 Below is a description of the currently available audio sources.
424 Null audio source, never return audio frames. It is mainly useful as a
425 template and to be employed in analysis / debugging tools.
427 It accepts as optional parameter a string of the form
428 @var{sample_rate}:@var{channel_layout}.
430 @var{sample_rate} specify the sample rate, and defaults to 44100.
432 @var{channel_layout} specify the channel layout, and can be either an
433 integer or a string representing a channel layout. The default value
434 of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
436 Check the channel_layout_map definition in
437 @file{libavutil/channel_layout.c} for the mapping between strings and
438 channel layout values.
440 Follow some examples:
442 # set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
450 Buffer audio frames, and make them available to the filter chain.
452 This source is not intended to be part of user-supplied graph descriptions but
453 for insertion by calling programs through the interface defined in
454 @file{libavfilter/buffersrc.h}.
456 It accepts the following named parameters:
460 Timebase which will be used for timestamps of submitted frames. It must be
461 either a floating-point number or in @var{numerator}/@var{denominator} form.
467 Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
470 Channel layout of the audio data, in the form that can be accepted by
471 @code{av_get_channel_layout()}.
474 All the parameters need to be explicitly defined.
476 @c man end AUDIO SOURCES
479 @c man begin AUDIO SINKS
481 Below is a description of the currently available audio sinks.
485 Null audio sink, do absolutely nothing with the input audio. It is
486 mainly useful as a template and to be employed in analysis / debugging
490 This sink is intended for programmatic use. Frames that arrive on this sink can
491 be retrieved by the calling program using the interface defined in
492 @file{libavfilter/buffersink.h}.
494 This filter accepts no parameters.
496 @c man end AUDIO SINKS
498 @chapter Video Filters
499 @c man begin VIDEO FILTERS
501 When you configure your Libav build, you can disable any of the
502 existing filters using --disable-filters.
503 The configure output will show the video filters included in your
506 Below is a description of the currently available video filters.
510 Detect frames that are (almost) completely black. Can be useful to
511 detect chapter transitions or commercials. Output lines consist of
512 the frame number of the detected frame, the percentage of blackness,
513 the position in the file if known or -1 and the timestamp in seconds.
515 In order to display the output lines, you need to set the loglevel at
516 least to the AV_LOG_INFO value.
518 The filter accepts the syntax:
520 blackframe[=@var{amount}:[@var{threshold}]]
523 @var{amount} is the percentage of the pixels that have to be below the
524 threshold, and defaults to 98.
526 @var{threshold} is the threshold below which a pixel value is
527 considered black, and defaults to 32.
531 Apply boxblur algorithm to the input video.
533 This filter accepts the parameters:
534 @var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
536 Chroma and alpha parameters are optional, if not specified they default
537 to the corresponding values set for @var{luma_radius} and
540 @var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
541 the radius in pixels of the box used for blurring the corresponding
542 input plane. They are expressions, and can contain the following
546 the input width and height in pixels
549 the input chroma image width and height in pixels
552 horizontal and vertical chroma subsample values. For example for the
553 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
556 The radius must be a non-negative number, and must not be greater than
557 the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
558 and of @code{min(cw,ch)/2} for the chroma planes.
560 @var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
561 how many times the boxblur filter is applied to the corresponding
564 Some examples follow:
569 Apply a boxblur filter with luma, chroma, and alpha radius
576 Set luma radius to 2, alpha and chroma radius to 0
582 Set luma and chroma radius to a fraction of the video dimension
584 boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
591 Copy the input source unchanged to the output. Mainly useful for
596 Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
598 The parameters are expressions containing the following constants:
602 the corresponding mathematical approximated values for e
603 (euler number), pi (greek PI), PHI (golden ratio)
606 the computed values for @var{x} and @var{y}. They are evaluated for
610 the input width and height
613 same as @var{in_w} and @var{in_h}
616 the output (cropped) width and height
619 same as @var{out_w} and @var{out_h}
622 the number of input frame, starting from 0
625 the position in the file of the input frame, NAN if unknown
628 timestamp expressed in seconds, NAN if the input timestamp is unknown
632 The @var{out_w} and @var{out_h} parameters specify the expressions for
633 the width and height of the output (cropped) video. They are
634 evaluated just at the configuration of the filter.
636 The default value of @var{out_w} is "in_w", and the default value of
637 @var{out_h} is "in_h".
639 The expression for @var{out_w} may depend on the value of @var{out_h},
640 and the expression for @var{out_h} may depend on @var{out_w}, but they
641 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
642 evaluated after @var{out_w} and @var{out_h}.
644 The @var{x} and @var{y} parameters specify the expressions for the
645 position of the top-left corner of the output (non-cropped) area. They
646 are evaluated for each frame. If the evaluated value is not valid, it
647 is approximated to the nearest valid value.
649 The default value of @var{x} is "(in_w-out_w)/2", and the default
650 value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
651 the center of the input image.
653 The expression for @var{x} may depend on @var{y}, and the expression
654 for @var{y} may depend on @var{x}.
656 Follow some examples:
658 # crop the central input area with size 100x100
661 # crop the central input area with size 2/3 of the input video
662 "crop=2/3*in_w:2/3*in_h"
664 # crop the input video central square
667 # delimit the rectangle with the top-left corner placed at position
668 # 100:100 and the right-bottom corner corresponding to the right-bottom
669 # corner of the input image.
670 crop=in_w-100:in_h-100:100:100
672 # crop 10 pixels from the left and right borders, and 20 pixels from
673 # the top and bottom borders
674 "crop=in_w-2*10:in_h-2*20"
676 # keep only the bottom right quarter of the input image
677 "crop=in_w/2:in_h/2:in_w/2:in_h/2"
679 # crop height for getting Greek harmony
680 "crop=in_w:1/PHI*in_w"
683 "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)"
685 # erratic camera effect depending on timestamp
686 "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)"
688 # set x depending on the value of y
689 "crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
694 Auto-detect crop size.
696 Calculate necessary cropping parameters and prints the recommended
697 parameters through the logging system. The detected dimensions
698 correspond to the non-black area of the input video.
700 It accepts the syntax:
702 cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
708 Threshold, which can be optionally specified from nothing (0) to
709 everything (255), defaults to 24.
712 Value which the width/height should be divisible by, defaults to
713 16. The offset is automatically adjusted to center the video. Use 2 to
714 get only even dimensions (needed for 4:2:2 video). 16 is best when
715 encoding to most video codecs.
718 Counter that determines after how many frames cropdetect will reset
719 the previously detected largest video area and start over to detect
720 the current optimal crop area. Defaults to 0.
722 This can be useful when channel logos distort the video area. 0
723 indicates never reset and return the largest area encountered during
729 Suppress a TV station logo by a simple interpolation of the surrounding
730 pixels. Just set a rectangle covering the logo and watch it disappear
731 (and sometimes something even uglier appear - your mileage may vary).
733 The filter accepts parameters as a string of the form
734 "@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
735 @var{key}=@var{value} pairs, separated by ":".
737 The description of the accepted parameters follows.
742 Specify the top left corner coordinates of the logo. They must be
746 Specify the width and height of the logo to clear. They must be
750 Specify the thickness of the fuzzy edge of the rectangle (added to
751 @var{w} and @var{h}). The default value is 4.
754 When set to 1, a green rectangle is drawn on the screen to simplify
755 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
756 @var{band} is set to 4. The default value is 0.
760 Some examples follow.
765 Set a rectangle covering the area with top left corner coordinates 0,0
766 and size 100x77, setting a band of size 10:
772 As the previous example, but use named options:
774 delogo=x=0:y=0:w=100:h=77:band=10
781 Draw a colored box on the input image.
783 It accepts the syntax:
785 drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
791 Specify the top left corner coordinates of the box. Default to 0.
794 Specify the width and height of the box, if 0 they are interpreted as
795 the input width and height. Default to 0.
798 Specify the color of the box to write, it can be the name of a color
799 (case insensitive match) or a 0xRRGGBB[AA] sequence.
802 Follow some examples:
804 # draw a black box around the edge of the input image
807 # draw a box with color red and an opacity of 50%
808 drawbox=10:20:200:60:red@@0.5"
813 Draw text string or text from specified file on top of video using the
816 To enable compilation of this filter you need to configure Libav with
817 @code{--enable-libfreetype}.
819 The filter also recognizes strftime() sequences in the provided text
820 and expands them accordingly. Check the documentation of strftime().
822 The filter accepts parameters as a list of @var{key}=@var{value} pairs,
825 The description of the accepted parameters follows.
830 The font file to be used for drawing text. Path must be included.
831 This parameter is mandatory.
834 The text string to be drawn. The text must be a sequence of UTF-8
836 This parameter is mandatory if no file is specified with the parameter
840 A text file containing text to be drawn. The text must be a sequence
841 of UTF-8 encoded characters.
843 This parameter is mandatory if no text string is specified with the
844 parameter @var{text}.
846 If both text and textfile are specified, an error is thrown.
849 The offsets where text will be drawn within the video frame.
850 Relative to the top/left border of the output image.
851 They accept expressions similar to the @ref{overlay} filter:
855 the computed values for @var{x} and @var{y}. They are evaluated for
859 main input width and height
862 same as @var{main_w} and @var{main_h}
865 rendered text width and height
868 same as @var{text_w} and @var{text_h}
871 the number of frames processed, starting from 0
874 timestamp expressed in seconds, NAN if the input timestamp is unknown
878 The default value of @var{x} and @var{y} is 0.
881 The font size to be used for drawing text.
882 The default value of @var{fontsize} is 16.
885 The color to be used for drawing fonts.
886 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
887 (e.g. "0xff000033"), possibly followed by an alpha specifier.
888 The default value of @var{fontcolor} is "black".
891 The color to be used for drawing box around text.
892 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
893 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
894 The default value of @var{boxcolor} is "white".
897 Used to draw a box around text using background color.
898 Value should be either 1 (enable) or 0 (disable).
899 The default value of @var{box} is 0.
901 @item shadowx, shadowy
902 The x and y offsets for the text shadow position with respect to the
903 position of the text. They can be either positive or negative
904 values. Default value for both is "0".
907 The color to be used for drawing a shadow behind the drawn text. It
908 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
909 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
910 The default value of @var{shadowcolor} is "black".
913 Flags to be used for loading the fonts.
915 The flags map the corresponding flags supported by libfreetype, and are
916 a combination of the following values:
923 @item vertical_layout
927 @item ignore_global_advance_width
929 @item ignore_transform
936 Default value is "render".
938 For more information consult the documentation for the FT_LOAD_*
942 The size in number of spaces to use for rendering the tab.
946 If true, check and fix text coords to avoid clipping.
949 For example the command:
951 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
954 will draw "Test Text" with font FreeSerif, using the default values
955 for the optional parameters.
959 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
960 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
963 will draw 'Test Text' with font FreeSerif of size 24 at position x=100
964 and y=50 (counting from the top-left corner of the screen), text is
965 yellow with a red box around it. Both the text and the box have an
968 Note that the double quotes are not necessary if spaces are not used
969 within the parameter list.
971 For more information about libfreetype, check:
972 @url{http://www.freetype.org/}.
976 Apply fade-in/out effect to input video.
978 It accepts the parameters:
979 @var{type}:@var{start_frame}:@var{nb_frames}
981 @var{type} specifies if the effect type, can be either "in" for
982 fade-in, or "out" for a fade-out effect.
984 @var{start_frame} specifies the number of the start frame for starting
985 to apply the fade effect.
987 @var{nb_frames} specifies the number of frames for which the fade
988 effect has to last. At the end of the fade-in effect the output video
989 will have the same intensity as the input video, at the end of the
990 fade-out transition the output video will be completely black.
992 A few usage examples follow, usable too as test scenarios.
994 # fade in first 30 frames of video
997 # fade out last 45 frames of a 200-frame video
1000 # fade in first 25 frames and fade out last 25 frames of a 1000-frame video
1001 fade=in:0:25, fade=out:975:25
1003 # make first 5 frames black, then fade in from frame 5-24
1009 Transform the field order of the input video.
1011 It accepts one parameter which specifies the required field order that
1012 the input interlaced video will be transformed to. The parameter can
1013 assume one of the following values:
1017 output bottom field first
1019 output top field first
1022 Default value is "tff".
1024 Transformation is achieved by shifting the picture content up or down
1025 by one line, and filling the remaining line with appropriate picture content.
1026 This method is consistent with most broadcast field order converters.
1028 If the input video is not flagged as being interlaced, or it is already
1029 flagged as being of the required output field order then this filter does
1030 not alter the incoming video.
1032 This filter is very useful when converting to or from PAL DV material,
1033 which is bottom field first.
1037 ./avconv -i in.vob -vf "fieldorder=bff" out.dv
1042 Buffer input images and send them when they are requested.
1044 This filter is mainly useful when auto-inserted by the libavfilter
1047 The filter does not take parameters.
1051 Convert the input video to one of the specified pixel formats.
1052 Libavfilter will try to pick one that is supported for the input to
1055 The filter accepts a list of pixel format names, separated by ":",
1056 for example "yuv420p:monow:rgb24".
1058 Some examples follow:
1060 # convert the input video to the format "yuv420p"
1063 # convert the input video to any of the formats in the list
1064 format=yuv420p:yuv444p:yuv410p
1069 Convert the video to specified constant framerate by duplicating or dropping
1070 frames as necessary.
1072 This filter accepts the following named parameters:
1076 Desired output framerate.
1083 Apply a frei0r effect to the input video.
1085 To enable compilation of this filter you need to install the frei0r
1086 header and configure Libav with --enable-frei0r.
1088 The filter supports the syntax:
1090 @var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
1093 @var{filter_name} is the name to the frei0r effect to load. If the
1094 environment variable @env{FREI0R_PATH} is defined, the frei0r effect
1095 is searched in each one of the directories specified by the colon
1096 separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
1097 paths, which are in this order: @file{HOME/.frei0r-1/lib/},
1098 @file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
1100 @var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
1101 for the frei0r effect.
1103 A frei0r effect parameter can be a boolean (whose values are specified
1104 with "y" and "n"), a double, a color (specified by the syntax
1105 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
1106 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
1107 description), a position (specified by the syntax @var{X}/@var{Y},
1108 @var{X} and @var{Y} being float numbers) and a string.
1110 The number and kind of parameters depend on the loaded effect. If an
1111 effect parameter is not specified the default value is set.
1113 Some examples follow:
1115 # apply the distort0r effect, set the first two double parameters
1116 frei0r=distort0r:0.5:0.01
1118 # apply the colordistance effect, takes a color as first parameter
1119 frei0r=colordistance:0.2/0.3/0.4
1120 frei0r=colordistance:violet
1121 frei0r=colordistance:0x112233
1123 # apply the perspective effect, specify the top left and top right
1125 frei0r=perspective:0.2/0.2:0.8/0.2
1128 For more information see:
1129 @url{http://piksel.org/frei0r}
1133 Fix the banding artifacts that are sometimes introduced into nearly flat
1134 regions by truncation to 8bit colordepth.
1135 Interpolate the gradients that should go where the bands are, and
1138 This filter is designed for playback only. Do not use it prior to
1139 lossy compression, because compression tends to lose the dither and
1140 bring back the bands.
1142 The filter takes two optional parameters, separated by ':':
1143 @var{strength}:@var{radius}
1145 @var{strength} is the maximum amount by which the filter will change
1146 any one pixel. Also the threshold for detecting nearly flat
1147 regions. Acceptable values range from .51 to 255, default value is
1148 1.2, out-of-range values will be clipped to the valid range.
1150 @var{radius} is the neighborhood to fit the gradient to. A larger
1151 radius makes for smoother gradients, but also prevents the filter from
1152 modifying the pixels near detailed regions. Acceptable values are
1153 8-32, default value is 16, out-of-range values will be clipped to the
1157 # default parameters
1166 Flip the input video horizontally.
1168 For example to horizontally flip the input video with @command{avconv}:
1170 avconv -i in.avi -vf "hflip" out.avi
1175 High precision/quality 3d denoise filter. This filter aims to reduce
1176 image noise producing smooth images and making still images really
1177 still. It should enhance compressibility.
1179 It accepts the following optional parameters:
1180 @var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
1184 a non-negative float number which specifies spatial luma strength,
1187 @item chroma_spatial
1188 a non-negative float number which specifies spatial chroma strength,
1189 defaults to 3.0*@var{luma_spatial}/4.0
1192 a float number which specifies luma temporal strength, defaults to
1193 6.0*@var{luma_spatial}/4.0
1196 a float number which specifies chroma temporal strength, defaults to
1197 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
1200 @section lut, lutrgb, lutyuv
1202 Compute a look-up table for binding each pixel component input value
1203 to an output value, and apply it to input video.
1205 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
1206 to an RGB input video.
1208 These filters accept in input a ":"-separated list of options, which
1209 specify the expressions used for computing the lookup table for the
1210 corresponding pixel component values.
1212 The @var{lut} filter requires either YUV or RGB pixel formats in
1213 input, and accepts the options:
1215 @item @var{c0} (first pixel component)
1216 @item @var{c1} (second pixel component)
1217 @item @var{c2} (third pixel component)
1218 @item @var{c3} (fourth pixel component, corresponds to the alpha component)
1221 The exact component associated to each option depends on the format in
1224 The @var{lutrgb} filter requires RGB pixel formats in input, and
1225 accepts the options:
1227 @item @var{r} (red component)
1228 @item @var{g} (green component)
1229 @item @var{b} (blue component)
1230 @item @var{a} (alpha component)
1233 The @var{lutyuv} filter requires YUV pixel formats in input, and
1234 accepts the options:
1236 @item @var{y} (Y/luminance component)
1237 @item @var{u} (U/Cb component)
1238 @item @var{v} (V/Cr component)
1239 @item @var{a} (alpha component)
1242 The expressions can contain the following constants and functions:
1246 the corresponding mathematical approximated values for e
1247 (euler number), pi (greek PI), PHI (golden ratio)
1250 the input width and height
1253 input value for the pixel component
1256 the input value clipped in the @var{minval}-@var{maxval} range
1259 maximum value for the pixel component
1262 minimum value for the pixel component
1265 the negated value for the pixel component value clipped in the
1266 @var{minval}-@var{maxval} range , it corresponds to the expression
1267 "maxval-clipval+minval"
1270 the computed value in @var{val} clipped in the
1271 @var{minval}-@var{maxval} range
1273 @item gammaval(gamma)
1274 the computed gamma correction value of the pixel component value
1275 clipped in the @var{minval}-@var{maxval} range, corresponds to the
1277 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
1281 All expressions default to "val".
1283 Some examples follow:
1285 # negate input video
1286 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
1287 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
1289 # the above is the same as
1290 lutrgb="r=negval:g=negval:b=negval"
1291 lutyuv="y=negval:u=negval:v=negval"
1296 # remove chroma components, turns the video into a graytone image
1297 lutyuv="u=128:v=128"
1299 # apply a luma burning effect
1302 # remove green and blue components
1305 # set a constant alpha channel value on input
1306 format=rgba,lutrgb=a="maxval-minval/2"
1308 # correct luminance gamma by a 0.5 factor
1309 lutyuv=y=gammaval(0.5)
1316 This filter accepts an integer in input, if non-zero it negates the
1317 alpha component (if available). The default value in input is 0.
1319 Force libavfilter not to use any of the specified pixel formats for the
1320 input to the next filter.
1322 The filter accepts a list of pixel format names, separated by ":",
1323 for example "yuv420p:monow:rgb24".
1325 Some examples follow:
1327 # force libavfilter to use a format different from "yuv420p" for the
1328 # input to the vflip filter
1329 noformat=yuv420p,vflip
1331 # convert the input video to any of the formats not contained in the list
1332 noformat=yuv420p:yuv444p:yuv410p
1337 Pass the video source unchanged to the output.
1341 Apply video transform using libopencv.
1343 To enable this filter install libopencv library and headers and
1344 configure Libav with --enable-libopencv.
1346 The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
1348 @var{filter_name} is the name of the libopencv filter to apply.
1350 @var{filter_params} specifies the parameters to pass to the libopencv
1351 filter. If not specified the default values are assumed.
1353 Refer to the official libopencv documentation for more precise
1355 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
1357 Follows the list of supported libopencv filters.
1362 Dilate an image by using a specific structuring element.
1363 This filter corresponds to the libopencv function @code{cvDilate}.
1365 It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
1367 @var{struct_el} represents a structuring element, and has the syntax:
1368 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
1370 @var{cols} and @var{rows} represent the number of columns and rows of
1371 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
1372 point, and @var{shape} the shape for the structuring element, and
1373 can be one of the values "rect", "cross", "ellipse", "custom".
1375 If the value for @var{shape} is "custom", it must be followed by a
1376 string of the form "=@var{filename}". The file with name
1377 @var{filename} is assumed to represent a binary image, with each
1378 printable character corresponding to a bright pixel. When a custom
1379 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
1380 or columns and rows of the read file are assumed instead.
1382 The default value for @var{struct_el} is "3x3+0x0/rect".
1384 @var{nb_iterations} specifies the number of times the transform is
1385 applied to the image, and defaults to 1.
1387 Follow some example:
1389 # use the default values
1392 # dilate using a structuring element with a 5x5 cross, iterate two times
1393 ocv=dilate=5x5+2x2/cross:2
1395 # read the shape from the file diamond.shape, iterate two times
1396 # the file diamond.shape may contain a pattern of characters like this:
1402 # the specified cols and rows are ignored (but not the anchor point coordinates)
1403 ocv=0x0+2x2/custom=diamond.shape:2
1408 Erode an image by using a specific structuring element.
1409 This filter corresponds to the libopencv function @code{cvErode}.
1411 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
1412 with the same syntax and semantics as the @ref{dilate} filter.
1416 Smooth the input video.
1418 The filter takes the following parameters:
1419 @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
1421 @var{type} is the type of smooth filter to apply, and can be one of
1422 the following values: "blur", "blur_no_scale", "median", "gaussian",
1423 "bilateral". The default value is "gaussian".
1425 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
1426 parameters whose meanings depend on smooth type. @var{param1} and
1427 @var{param2} accept integer positive values or 0, @var{param3} and
1428 @var{param4} accept float values.
1430 The default value for @var{param1} is 3, the default value for the
1431 other parameters is 0.
1433 These parameters correspond to the parameters assigned to the
1434 libopencv function @code{cvSmooth}.
1439 Overlay one video on top of another.
1441 It takes two inputs and one output, the first input is the "main"
1442 video on which the second input is overlayed.
1444 It accepts the parameters: @var{x}:@var{y}.
1446 @var{x} is the x coordinate of the overlayed video on the main video,
1447 @var{y} is the y coordinate. The parameters are expressions containing
1448 the following parameters:
1451 @item main_w, main_h
1452 main input width and height
1455 same as @var{main_w} and @var{main_h}
1457 @item overlay_w, overlay_h
1458 overlay input width and height
1461 same as @var{overlay_w} and @var{overlay_h}
1464 Be aware that frames are taken from each input video in timestamp
1465 order, hence, if their initial timestamps differ, it is a a good idea
1466 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
1467 have them begin in the same zero timestamp, as it does the example for
1468 the @var{movie} filter.
1470 Follow some examples:
1472 # draw the overlay at 10 pixels from the bottom right
1473 # corner of the main video.
1474 overlay=main_w-overlay_w-10:main_h-overlay_h-10
1476 # insert a transparent PNG logo in the bottom left corner of the input
1477 avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
1479 # insert 2 different transparent PNG logos (second logo on bottom
1481 avconv -i input -i logo1 -i logo2 -filter_complex
1482 'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
1484 # add a transparent color layer on top of the main video,
1485 # WxH specifies the size of the main input to the overlay filter
1486 color=red@.3:WxH [over]; [in][over] overlay [out]
1489 You can chain together more overlays but the efficiency of such
1490 approach is yet to be tested.
1494 Add paddings to the input image, and places the original input at the
1495 given coordinates @var{x}, @var{y}.
1497 It accepts the following parameters:
1498 @var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
1500 The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
1501 expressions containing the following constants:
1505 the corresponding mathematical approximated values for e
1506 (euler number), pi (greek PI), phi (golden ratio)
1509 the input video width and height
1512 same as @var{in_w} and @var{in_h}
1515 the output width and height, that is the size of the padded area as
1516 specified by the @var{width} and @var{height} expressions
1519 same as @var{out_w} and @var{out_h}
1522 x and y offsets as specified by the @var{x} and @var{y}
1523 expressions, or NAN if not yet specified
1526 input display aspect ratio, same as @var{iw} / @var{ih}
1529 horizontal and vertical chroma subsample values. For example for the
1530 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1533 Follows the description of the accepted parameters.
1538 Specify the size of the output image with the paddings added. If the
1539 value for @var{width} or @var{height} is 0, the corresponding input size
1540 is used for the output.
1542 The @var{width} expression can reference the value set by the
1543 @var{height} expression, and vice versa.
1545 The default value of @var{width} and @var{height} is 0.
1549 Specify the offsets where to place the input image in the padded area
1550 with respect to the top/left border of the output image.
1552 The @var{x} expression can reference the value set by the @var{y}
1553 expression, and vice versa.
1555 The default value of @var{x} and @var{y} is 0.
1559 Specify the color of the padded area, it can be the name of a color
1560 (case insensitive match) or a 0xRRGGBB[AA] sequence.
1562 The default value of @var{color} is "black".
1566 Some examples follow:
1569 # Add paddings with color "violet" to the input video. Output video
1570 # size is 640x480, the top-left corner of the input video is placed at
1572 pad=640:480:0:40:violet
1574 # pad the input to get an output with dimensions increased bt 3/2,
1575 # and put the input video at the center of the padded area
1576 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
1578 # pad the input to get a squared output with size equal to the maximum
1579 # value between the input width and height, and put the input video at
1580 # the center of the padded area
1581 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
1583 # pad the input to get a final w/h ratio of 16:9
1584 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
1586 # double output size and put the input video in the bottom-right
1587 # corner of the output padded area
1588 pad="2*iw:2*ih:ow-iw:oh-ih"
1591 @section pixdesctest
1593 Pixel format descriptor test filter, mainly useful for internal
1594 testing. The output video should be equal to the input video.
1598 format=monow, pixdesctest
1601 can be used to test the monowhite pixel format descriptor definition.
1605 Scale the input video to @var{width}:@var{height} and/or convert the image format.
1607 The parameters @var{width} and @var{height} are expressions containing
1608 the following constants:
1612 the corresponding mathematical approximated values for e
1613 (euler number), pi (greek PI), phi (golden ratio)
1616 the input width and height
1619 same as @var{in_w} and @var{in_h}
1622 the output (cropped) width and height
1625 same as @var{out_w} and @var{out_h}
1628 input display aspect ratio, same as @var{iw} / @var{ih}
1631 input sample aspect ratio
1634 horizontal and vertical chroma subsample values. For example for the
1635 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
1638 If the input image format is different from the format requested by
1639 the next filter, the scale filter will convert the input to the
1642 If the value for @var{width} or @var{height} is 0, the respective input
1643 size is used for the output.
1645 If the value for @var{width} or @var{height} is -1, the scale filter will
1646 use, for the respective output size, a value that maintains the aspect
1647 ratio of the input image.
1649 The default value of @var{width} and @var{height} is 0.
1651 Some examples follow:
1653 # scale the input video to a size of 200x100.
1656 # scale the input to 2x
1658 # the above is the same as
1661 # scale the input to half size
1664 # increase the width, and set the height to the same size
1667 # seek for Greek harmony
1671 # increase the height, and set the width to 3/2 of the height
1674 # increase the size, but make the size a multiple of the chroma
1675 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
1677 # increase the width to a maximum of 500 pixels, keep the same input aspect ratio
1678 scale='min(500\, iw*3/2):-1'
1682 Select frames to pass in output.
1684 It accepts in input an expression, which is evaluated for each input
1685 frame. If the expression is evaluated to a non-zero value, the frame
1686 is selected and passed to the output, otherwise it is discarded.
1688 The expression can contain the following constants:
1701 the sequential number of the filtered frame, starting from 0
1704 the sequential number of the selected frame, starting from 0
1706 @item prev_selected_n
1707 the sequential number of the last selected frame, NAN if undefined
1710 timebase of the input timestamps
1713 the PTS (Presentation TimeStamp) of the filtered video frame,
1714 expressed in @var{TB} units, NAN if undefined
1717 the PTS (Presentation TimeStamp) of the filtered video frame,
1718 expressed in seconds, NAN if undefined
1721 the PTS of the previously filtered video frame, NAN if undefined
1723 @item prev_selected_pts
1724 the PTS of the last previously filtered video frame, NAN if undefined
1726 @item prev_selected_t
1727 the PTS of the last previously selected video frame, NAN if undefined
1730 the PTS of the first video frame in the video, NAN if undefined
1733 the time of the first video frame in the video, NAN if undefined
1736 the type of the filtered frame, can assume one of the following
1748 @item interlace_type
1749 the frame interlace type, can assume one of the following values:
1752 the frame is progressive (not interlaced)
1754 the frame is top-field-first
1756 the frame is bottom-field-first
1760 1 if the filtered frame is a key-frame, 0 otherwise
1763 the position in the file of the filtered frame, -1 if the information
1764 is not available (e.g. for synthetic video)
1767 The default value of the select expression is "1".
1769 Some examples follow:
1772 # select all frames in input
1775 # the above is the same as:
1781 # select only I-frames
1782 select='eq(pict_type\,I)'
1784 # select one frame every 100
1785 select='not(mod(n\,100))'
1787 # select only frames contained in the 10-20 time interval
1788 select='gte(t\,10)*lte(t\,20)'
1790 # select only I frames contained in the 10-20 time interval
1791 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
1793 # select frames with a minimum distance of 10 seconds
1794 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
1800 Set the Display Aspect Ratio for the filter output video.
1802 This is done by changing the specified Sample (aka Pixel) Aspect
1803 Ratio, according to the following equation:
1804 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1806 Keep in mind that this filter does not modify the pixel dimensions of
1807 the video frame. Also the display aspect ratio set by this filter may
1808 be changed by later filters in the filterchain, e.g. in case of
1809 scaling or if another "setdar" or a "setsar" filter is applied.
1811 The filter accepts a parameter string which represents the wanted
1812 display aspect ratio.
1813 The parameter can be a floating point number string, or an expression
1814 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1815 numerator and denominator of the aspect ratio.
1816 If the parameter is not specified, it is assumed the value "0:1".
1818 For example to change the display aspect ratio to 16:9, specify:
1821 # the above is equivalent to
1825 See also the @ref{setsar} filter documentation.
1829 Change the PTS (presentation timestamp) of the input video frames.
1831 Accept in input an expression evaluated through the eval API, which
1832 can contain the following constants:
1836 the presentation timestamp in input
1848 the count of the input frame, starting from 0.
1851 the PTS of the first video frame
1854 tell if the current frame is interlaced
1857 original position in the file of the frame, or undefined if undefined
1858 for the current frame
1868 Some examples follow:
1871 # start counting PTS from zero
1883 # fixed rate 25 fps with some jitter
1884 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
1890 Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
1892 Note that as a consequence of the application of this filter, the
1893 output display aspect ratio will change according to the following
1895 @math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
1897 Keep in mind that the sample aspect ratio set by this filter may be
1898 changed by later filters in the filterchain, e.g. if another "setsar"
1899 or a "setdar" filter is applied.
1901 The filter accepts a parameter string which represents the wanted
1902 sample aspect ratio.
1903 The parameter can be a floating point number string, or an expression
1904 of the form @var{num}:@var{den}, where @var{num} and @var{den} are the
1905 numerator and denominator of the aspect ratio.
1906 If the parameter is not specified, it is assumed the value "0:1".
1908 For example to change the sample aspect ratio to 10:11, specify:
1915 Set the timebase to use for the output frames timestamps.
1916 It is mainly useful for testing timebase configuration.
1918 It accepts in input an arithmetic expression representing a rational.
1919 The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
1920 default timebase), and "intb" (the input timebase).
1922 The default value for the input is "intb".
1924 Follow some examples.
1927 # set the timebase to 1/25
1930 # set the timebase to 1/10
1933 #set the timebase to 1001/1000
1936 #set the timebase to 2*intb
1939 #set the default timebase value
1945 Show a line containing various information for each input video frame.
1946 The input video is not modified.
1948 The shown line contains a sequence of key/value pairs of the form
1949 @var{key}:@var{value}.
1951 A description of each shown parameter follows:
1955 sequential number of the input frame, starting from 0
1958 Presentation TimeStamp of the input frame, expressed as a number of
1959 time base units. The time base unit depends on the filter input pad.
1962 Presentation TimeStamp of the input frame, expressed as a number of
1966 position of the frame in the input stream, -1 if this information in
1967 unavailable and/or meaningless (for example in case of synthetic video)
1973 sample aspect ratio of the input frame, expressed in the form
1977 size of the input frame, expressed in the form
1978 @var{width}x@var{height}
1981 interlaced mode ("P" for "progressive", "T" for top field first, "B"
1982 for bottom field first)
1985 1 if the frame is a key frame, 0 otherwise
1988 picture type of the input frame ("I" for an I-frame, "P" for a
1989 P-frame, "B" for a B-frame, "?" for unknown type).
1990 Check also the documentation of the @code{AVPictureType} enum and of
1991 the @code{av_get_picture_type_char} function defined in
1992 @file{libavutil/avutil.h}.
1995 Adler-32 checksum of all the planes of the input frame
1997 @item plane_checksum
1998 Adler-32 checksum of each plane of the input frame, expressed in the form
1999 "[@var{c0} @var{c1} @var{c2} @var{c3}]"
2004 Split input video into several identical outputs.
2006 The filter accepts a single parameter which specifies the number of outputs. If
2007 unspecified, it defaults to 2.
2011 avconv -i INPUT -filter_complex split=5 OUTPUT
2013 will create 5 copies of the input video.
2017 Transpose rows with columns in the input video and optionally flip it.
2019 It accepts a parameter representing an integer, which can assume the
2024 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
2032 Rotate by 90 degrees clockwise, that is:
2040 Rotate by 90 degrees counterclockwise, that is:
2048 Rotate by 90 degrees clockwise and vertically flip, that is:
2058 Sharpen or blur the input video.
2060 It accepts the following parameters:
2061 @var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
2063 Negative values for the amount will blur the input video, while positive
2064 values will sharpen. All parameters are optional and default to the
2065 equivalent of the string '5:5:1.0:5:5:0.0'.
2070 Set the luma matrix horizontal size. It can be an integer between 3
2071 and 13, default value is 5.
2074 Set the luma matrix vertical size. It can be an integer between 3
2075 and 13, default value is 5.
2078 Set the luma effect strength. It can be a float number between -2.0
2079 and 5.0, default value is 1.0.
2081 @item chroma_msize_x
2082 Set the chroma matrix horizontal size. It can be an integer between 3
2083 and 13, default value is 5.
2085 @item chroma_msize_y
2086 Set the chroma matrix vertical size. It can be an integer between 3
2087 and 13, default value is 5.
2090 Set the chroma effect strength. It can be a float number between -2.0
2091 and 5.0, default value is 0.0.
2096 # Strong luma sharpen effect parameters
2099 # Strong blur of both luma and chroma parameters
2100 unsharp=7:7:-2:7:7:-2
2102 # Use the default values with @command{avconv}
2103 ./avconv -i in.avi -vf "unsharp" out.mp4
2108 Flip the input video vertically.
2111 ./avconv -i in.avi -vf "vflip" out.avi
2116 Deinterlace the input video ("yadif" means "yet another deinterlacing
2119 It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
2121 @var{mode} specifies the interlacing mode to adopt, accepts one of the
2126 output 1 frame for each frame
2128 output 1 frame for each field
2130 like 0 but skips spatial interlacing check
2132 like 1 but skips spatial interlacing check
2137 @var{parity} specifies the picture field parity assumed for the input
2138 interlaced video, accepts one of the following values:
2142 assume top field first
2144 assume bottom field first
2146 enable automatic detection
2149 Default value is -1.
2150 If interlacing is unknown or decoder does not export this information,
2151 top field first will be assumed.
2153 @var{auto} specifies if deinterlacer should trust the interlaced flag
2154 and only deinterlace frames marked as interlaced
2158 deinterlace all frames
2160 only deinterlace frames marked as interlaced
2165 @c man end VIDEO FILTERS
2167 @chapter Video Sources
2168 @c man begin VIDEO SOURCES
2170 Below is a description of the currently available video sources.
2174 Buffer video frames, and make them available to the filter chain.
2176 This source is mainly intended for a programmatic use, in particular
2177 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
2179 It accepts the following parameters:
2180 @var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
2182 All the parameters need to be explicitly defined.
2184 Follows the list of the accepted parameters.
2189 Specify the width and height of the buffered video frames.
2191 @item pix_fmt_string
2192 A string representing the pixel format of the buffered video frames.
2193 It may be a number corresponding to a pixel format, or a pixel format
2196 @item timebase_num, timebase_den
2197 Specify numerator and denomitor of the timebase assumed by the
2198 timestamps of the buffered frames.
2200 @item sample_aspect_ratio.num, sample_aspect_ratio.den
2201 Specify numerator and denominator of the sample aspect ratio assumed
2202 by the video frames.
2207 buffer=320:240:yuv410p:1:24:1:1
2210 will instruct the source to accept video frames with size 320x240 and
2211 with format "yuv410p", assuming 1/24 as the timestamps timebase and
2212 square pixels (1:1 sample aspect ratio).
2213 Since the pixel format with name "yuv410p" corresponds to the number 6
2214 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
2215 this example corresponds to:
2217 buffer=320:240:6:1:24
2222 Provide an uniformly colored input.
2224 It accepts the following parameters:
2225 @var{color}:@var{frame_size}:@var{frame_rate}
2227 Follows the description of the accepted parameters.
2232 Specify the color of the source. It can be the name of a color (case
2233 insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
2234 alpha specifier. The default value is "black".
2237 Specify the size of the sourced video, it may be a string of the form
2238 @var{width}x@var{height}, or the name of a size abbreviation. The
2239 default value is "320x240".
2242 Specify the frame rate of the sourced video, as the number of frames
2243 generated per second. It has to be a string in the format
2244 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2245 number or a valid video frame rate abbreviation. The default value is
2250 For example the following graph description will generate a red source
2251 with an opacity of 0.2, with size "qcif" and a frame rate of 10
2252 frames per second, which will be overlayed over the source connected
2253 to the pad with identifier "in".
2256 "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
2261 Read a video stream from a movie container.
2263 Note that this source is a hack that bypasses the standard input path. It can be
2264 useful in applications that do not support arbitrary filter graphs, but its use
2265 is discouraged in those that do. Specifically in @command{avconv} this filter
2266 should never be used, the @option{-filter_complex} option fully replaces it.
2268 It accepts the syntax: @var{movie_name}[:@var{options}] where
2269 @var{movie_name} is the name of the resource to read (not necessarily
2270 a file but also a device or a stream accessed through some protocol),
2271 and @var{options} is an optional sequence of @var{key}=@var{value}
2272 pairs, separated by ":".
2274 The description of the accepted options follows.
2278 @item format_name, f
2279 Specifies the format assumed for the movie to read, and can be either
2280 the name of a container or an input device. If not specified the
2281 format is guessed from @var{movie_name} or by probing.
2283 @item seek_point, sp
2284 Specifies the seek point in seconds, the frames will be output
2285 starting from this seek point, the parameter is evaluated with
2286 @code{av_strtod} so the numerical value may be suffixed by an IS
2287 postfix. Default value is "0".
2289 @item stream_index, si
2290 Specifies the index of the video stream to read. If the value is -1,
2291 the best suited video stream will be automatically selected. Default
2296 This filter allows to overlay a second video on top of main input of
2297 a filtergraph as shown in this graph:
2299 input -----------> deltapts0 --> overlay --> output
2302 movie --> scale--> deltapts1 -------+
2305 Some examples follow:
2307 # skip 3.2 seconds from the start of the avi file in.avi, and overlay it
2308 # on top of the input labelled as "in".
2309 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2310 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2312 # read from a video4linux2 device, and overlay it on top of the input
2314 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
2315 [in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
2321 Null video source, never return images. It is mainly useful as a
2322 template and to be employed in analysis / debugging tools.
2324 It accepts as optional parameter a string of the form
2325 @var{width}:@var{height}:@var{timebase}.
2327 @var{width} and @var{height} specify the size of the configured
2328 source. The default values of @var{width} and @var{height} are
2329 respectively 352 and 288 (corresponding to the CIF size format).
2331 @var{timebase} specifies an arithmetic expression representing a
2332 timebase. The expression can contain the constants "PI", "E", "PHI",
2333 "AVTB" (the default timebase), and defaults to the value "AVTB".
2337 Provide a frei0r source.
2339 To enable compilation of this filter you need to install the frei0r
2340 header and configure Libav with --enable-frei0r.
2342 The source supports the syntax:
2344 @var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
2347 @var{size} is the size of the video to generate, may be a string of the
2348 form @var{width}x@var{height} or a frame size abbreviation.
2349 @var{rate} is the rate of the video to generate, may be a string of
2350 the form @var{num}/@var{den} or a frame rate abbreviation.
2351 @var{src_name} is the name to the frei0r source to load. For more
2352 information regarding frei0r and how to set the parameters read the
2353 section @ref{frei0r} in the description of the video filters.
2355 Some examples follow:
2357 # generate a frei0r partik0l source with size 200x200 and framerate 10
2358 # which is overlayed on the overlay filter main input
2359 frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
2362 @section rgbtestsrc, testsrc
2364 The @code{rgbtestsrc} source generates an RGB test pattern useful for
2365 detecting RGB vs BGR issues. You should see a red, green and blue
2366 stripe from top to bottom.
2368 The @code{testsrc} source generates a test video pattern, showing a
2369 color pattern, a scrolling gradient and a timestamp. This is mainly
2370 intended for testing purposes.
2372 Both sources accept an optional sequence of @var{key}=@var{value} pairs,
2373 separated by ":". The description of the accepted options follows.
2378 Specify the size of the sourced video, it may be a string of the form
2379 @var{width}x@var{height}, or the name of a size abbreviation. The
2380 default value is "320x240".
2383 Specify the frame rate of the sourced video, as the number of frames
2384 generated per second. It has to be a string in the format
2385 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
2386 number or a valid video frame rate abbreviation. The default value is
2390 Set the sample aspect ratio of the sourced video.
2393 Set the video duration of the sourced video. The accepted syntax is:
2395 [-]HH[:MM[:SS[.m...]]]
2398 See also the function @code{av_parse_time()}.
2400 If not specified, or the expressed duration is negative, the video is
2401 supposed to be generated forever.
2404 For example the following:
2406 testsrc=duration=5.3:size=qcif:rate=10
2409 will generate a video with a duration of 5.3 seconds, with size
2410 176x144 and a framerate of 10 frames per second.
2412 @c man end VIDEO SOURCES
2414 @chapter Video Sinks
2415 @c man begin VIDEO SINKS
2417 Below is a description of the currently available video sinks.
2421 Buffer video frames, and make them available to the end of the filter
2424 This sink is intended for a programmatic use through the interface defined in
2425 @file{libavfilter/buffersink.h}.
2429 Null video sink, do absolutely nothing with the input video. It is
2430 mainly useful as a template and to be employed in analysis / debugging
2433 @c man end VIDEO SINKS