X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=doc%2Ffilters.texi;h=d8d9062bb964c92706ddc502c25ffa0646d16fe1;hb=ee42716b07073549cefabec466a33fad39ed5eb6;hp=5ebaf99f4c51f33787930bea46ec0efaa48325ba;hpb=13fabd7a8d6b01587cfc5049549d2e389b568182;p=ffmpeg diff --git a/doc/filters.texi b/doc/filters.texi index 5ebaf99f4c5..d8d9062bb96 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -1,7 +1,98 @@ +@chapter Filtergraph description +@c man begin FILTERGRAPH DESCRIPTION + +A filtergraph is a directed graph of connected filters. It can contain +cycles, and there can be multiple links between a pair of +filters. Each link has one input pad on one side connecting it to one +filter from which it takes its input, and one output pad on the other +side connecting it to the one filter accepting its output. + +Each filter in a filtergraph is an instance of a filter class +registered in the application, which defines the features and the +number of input and output pads of the filter. + +A filter with no input pads is called a "source", a filter with no +output pads is called a "sink". + +@section Filtergraph syntax + +A filtergraph can be represented using a textual representation, which +is recognized by the @code{-vf} and @code{-af} options of the ff* +tools, and by the @code{av_parse_graph()} function defined in +@file{libavfilter/avfiltergraph}. + +A filterchain consists of a sequence of connected filters, each one +connected to the previous one in the sequence. A filterchain is +represented by a list of ","-separated filter descriptions. + +A filtergraph consists of a sequence of filterchains. A sequence of +filterchains is represented by a list of ";"-separated filterchain +descriptions. + +A filter is represented by a string of the form: +[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}] + +@var{filter_name} is the name of the filter class of which the +described filter is an instance of, and has to be the name of one of +the filter classes registered in the program. +The name of the filter class is optionally followed by a string +"=@var{arguments}". + +@var{arguments} is a string which contains the parameters used to +initialize the filter instance, and are described in the filter +descriptions below. + +The list of arguments can be quoted using the character "'" as initial +and ending mark, and the character '\' for escaping the characters +within the quoted text; otherwise the argument string is considered +terminated when the next special character (belonging to the set +"[]=;,") is encountered. + +The name and arguments of the filter are optionally preceded and +followed by a list of link labels. +A link label allows to name a link and associate it to a filter output +or input pad. The preceding labels @var{in_link_1} +... @var{in_link_N}, are associated to the filter input pads, +the following labels @var{out_link_1} ... @var{out_link_M}, are +associated to the output pads. + +When two link labels with the same name are found in the +filtergraph, a link between the corresponding input and output pad is +created. + +If an output pad is not labelled, it is linked by default to the first +unlabelled input pad of the next filter in the filterchain. +For example in the filterchain: +@example +nullsrc, split[L1], [L2]overlay, nullsink +@end example +the split filter instance has two output pads, and the overlay filter +instance two input pads. The first output pad of split is labelled +"L1", the first input pad of overlay is labelled "L2", and the second +output pad of split is linked to the second input pad of overlay, +which are both unlabelled. + +In a complete filterchain all the unlabelled filter input and output +pads must be connected. A filtergraph is considered valid if all the +filter input and output pads of all the filterchains are connected. + +Follows a BNF description for the filtergraph syntax: +@example +@var{NAME} ::= sequence of alphanumeric characters and '_' +@var{LINKLABEL} ::= "[" @var{NAME} "]" +@var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}] +@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted) +@var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}] +@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}] +@var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}] +@end example + +@c man end FILTERGRAPH DESCRIPTION + @chapter Audio Filters @c man begin AUDIO FILTERS -When you configure your FFmpeg build, you can disable any of the +When you configure your Libav build, you can disable any of the existing filters using --disable-filters. The configure output will show the audio filters included in your build. @@ -64,7 +155,7 @@ tools. @chapter Video Filters @c man begin VIDEO FILTERS -When you configure your FFmpeg build, you can disable any of the +When you configure your Libav build, you can disable any of the existing filters using --disable-filters. The configure output will show the video filters included in your build. @@ -92,6 +183,11 @@ threshold, and defaults to 98. @var{threshold} is the threshold below which a pixel value is considered black, and defaults to 32. +@section copy + +Copy the input source unchanged to the output. Mainly useful for +testing purposes. + @section crop Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}. @@ -170,7 +266,7 @@ crop=in_h # corner of the input image. crop=in_w-100:in_h-100:100:100 -# crop 10 pixels from the lefth and right borders, and 20 pixels from +# crop 10 pixels from the left and right borders, and 20 pixels from # the top and bottom borders "crop=in_w-2*10:in_h-2*20" @@ -183,13 +279,280 @@ crop=in_w-100:in_h-100:100:100 # trembling effect "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)" -# erratic camera effect depending on timestamp and position +# erratic camera effect depending on timestamp "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)" # set x depending on the value of y "crop=in_w/2:in_h/2:y:10+10*sin(n/10)" @end example +@section cropdetect + +Auto-detect crop size. + +Calculate necessary cropping parameters and prints the recommended +parameters through the logging system. The detected dimensions +correspond to the non-black area of the input video. + +It accepts the syntax: +@example +cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]] +@end example + +@table @option + +@item limit +Threshold, which can be optionally specified from nothing (0) to +everything (255), defaults to 24. + +@item round +Value which the width/height should be divisible by, defaults to +16. The offset is automatically adjusted to center the video. Use 2 to +get only even dimensions (needed for 4:2:2 video). 16 is best when +encoding to most video codecs. + +@item reset +Counter that determines after how many frames cropdetect will reset +the previously detected largest video area and start over to detect +the current optimal crop area. Defaults to 0. + +This can be useful when channel logos distort the video area. 0 +indicates never reset and return the largest area encountered during +playback. +@end table + +@section drawbox + +Draw a colored box on the input image. + +It accepts the syntax: +@example +drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color} +@end example + +@table @option + +@item x, y +Specify the top left corner coordinates of the box. Default to 0. + +@item width, height +Specify the width and height of the box, if 0 they are interpreted as +the input width and height. Default to 0. + +@item color +Specify the color of the box to write, it can be the name of a color +(case insensitive match) or a 0xRRGGBB[AA] sequence. +@end table + +Follow some examples: +@example +# draw a black box around the edge of the input image +drawbox + +# draw a box with color red and an opacity of 50% +drawbox=10:20:200:60:red@@0.5" +@end example + +@section drawtext + +Draw text string or text from specified file on top of video using the +libfreetype library. + +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libfreetype}. + +The filter also recognizes strftime() sequences in the provided text +and expands them accordingly. Check the documentation of strftime(). + +The filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +The description of the accepted parameters follows. + +@table @option + +@item fontfile +The font file to be used for drawing text. Path must be included. +This parameter is mandatory. + +@item text +The text string to be drawn. The text must be a sequence of UTF-8 +encoded characters. +This parameter is mandatory if no file is specified with the parameter +@var{textfile}. + +@item textfile +A text file containing text to be drawn. The text must be a sequence +of UTF-8 encoded characters. + +This parameter is mandatory if no text string is specified with the +parameter @var{text}. + +If both text and textfile are specified, an error is thrown. + +@item x, y +The offsets where text will be drawn within the video frame. +Relative to the top/left border of the output image. + +The default value of @var{x} and @var{y} is 0. + +@item fontsize +The font size to be used for drawing text. +The default value of @var{fontsize} is 16. + +@item fontcolor +The color to be used for drawing fonts. +Either a string (e.g. "red") or in 0xRRGGBB[AA] format +(e.g. "0xff000033"), possibly followed by an alpha specifier. +The default value of @var{fontcolor} is "black". + +@item boxcolor +The color to be used for drawing box around text. +Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format +(e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{boxcolor} is "white". + +@item box +Used to draw a box around text using background color. +Value should be either 1 (enable) or 0 (disable). +The default value of @var{box} is 0. + +@item shadowx, shadowy +The x and y offsets for the text shadow position with respect to the +position of the text. They can be either positive or negative +values. Default value for both is "0". + +@item shadowcolor +The color to be used for drawing a shadow behind the drawn text. It +can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] +form (e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{shadowcolor} is "black". + +@item ft_load_flags +Flags to be used for loading the fonts. + +The flags map the corresponding flags supported by libfreetype, and are +a combination of the following values: +@table @var +@item default +@item no_scale +@item no_hinting +@item render +@item no_bitmap +@item vertical_layout +@item force_autohint +@item crop_bitmap +@item pedantic +@item ignore_global_advance_width +@item no_recurse +@item ignore_transform +@item monochrome +@item linear_design +@item no_autohint +@item end table +@end table + +Default value is "render". + +For more information consult the documentation for the FT_LOAD_* +libfreetype flags. + +@item tabsize +The size in number of spaces to use for rendering the tab. +Default value is 4. +@end table + +For example the command: +@example +drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'" +@end example + +will draw "Test Text" with font FreeSerif, using the default values +for the optional parameters. + +The command: +@example +drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\ + x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2" +@end example + +will draw 'Test Text' with font FreeSerif of size 24 at position x=100 +and y=50 (counting from the top-left corner of the screen), text is +yellow with a red box around it. Both the text and the box have an +opacity of 20%. + +Note that the double quotes are not necessary if spaces are not used +within the parameter list. + +For more information about libfreetype, check: +@url{http://www.freetype.org/}. + +@section fade + +Apply fade-in/out effect to input video. + +It accepts the parameters: +@var{type}:@var{start_frame}:@var{nb_frames} + +@var{type} specifies if the effect type, can be either "in" for +fade-in, or "out" for a fade-out effect. + +@var{start_frame} specifies the number of the start frame for starting +to apply the fade effect. + +@var{nb_frames} specifies the number of frames for which the fade +effect has to last. At the end of the fade-in effect the output video +will have the same intensity as the input video, at the end of the +fade-out transition the output video will be completely black. + +A few usage examples follow, usable too as test scenarios. +@example +# fade in first 30 frames of video +fade=in:0:30 + +# fade out last 45 frames of a 200-frame video +fade=out:155:45 + +# fade in first 25 frames and fade out last 25 frames of a 1000-frame video +fade=in:0:25, fade=out:975:25 + +# make first 5 frames black, then fade in from frame 5-24 +fade=in:5:20 +@end example + +@section fieldorder + +Transform the field order of the input video. + +It accepts one parameter which specifies the required field order that +the input interlaced video will be transformed to. The parameter can +assume one of the following values: + +@table @option +@item 0 or bff +output bottom field first +@item 1 or tff +output top field first +@end table + +Default value is "tff". + +Transformation is achieved by shifting the picture content up or down +by one line, and filling the remaining line with appropriate picture content. +This method is consistent with most broadcast field order converters. + +If the input video is not flagged as being interlaced, or it is already +flagged as being of the required output field order then this filter does +not alter the incoming video. + +This filter is very useful when converting to or from PAL DV material, +which is bottom field first. + +For example: +@example +./ffmpeg -i in.vob -vf "fieldorder=bff" out.dv +@end example + @section fifo Buffer input images and send them when they are requested. @@ -208,24 +571,26 @@ the next filter. The filter accepts a list of pixel format names, separated by ":", for example "yuv420p:monow:rgb24". -The following command: - +Some examples follow: @example -./ffmpeg -i in.avi -vf "format=yuv420p" out.avi -@end example +# convert the input video to the format "yuv420p" +format=yuv420p -will convert the input video to the format "yuv420p". +# convert the input video to any of the formats in the list +format=yuv420p:yuv444p:yuv410p +@end example +@anchor{frei0r} @section frei0r Apply a frei0r effect to the input video. To enable compilation of this filter you need to install the frei0r -header and configure FFmpeg with --enable-frei0r. +header and configure Libav with --enable-frei0r. The filter supports the syntax: @example -@var{filter_name}:@var{param1}:@var{param2}:...:@var{paramN} +@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}] @end example @var{filter_name} is the name to the frei0r effect to load. If the @@ -266,6 +631,39 @@ frei0r=perspective:0.2/0.2:0.8/0.2 For more information see: @url{http://piksel.org/frei0r} +@section gradfun + +Fix the banding artifacts that are sometimes introduced into nearly flat +regions by truncation to 8bit colordepth. +Interpolate the gradients that should go where the bands are, and +dither them. + +This filter is designed for playback only. Do not use it prior to +lossy compression, because compression tends to lose the dither and +bring back the bands. + +The filter takes two optional parameters, separated by ':': +@var{strength}:@var{radius} + +@var{strength} is the maximum amount by which the filter will change +any one pixel. Also the threshold for detecting nearly flat +regions. Acceptable values range from .51 to 255, default value is +1.2, out-of-range values will be clipped to the valid range. + +@var{radius} is the neighborhood to fit the gradient to. A larger +radius makes for smoother gradients, but also prevents the filter from +modifying the pixels near detailed regions. Acceptable values are +8-32, default value is 16, out-of-range values will be clipped to the +valid range. + +@example +# default parameters +gradfun=1.2:16 + +# omitting radius +gradfun=1.2 +@end example + @section hflip Flip the input video horizontally. @@ -276,6 +674,33 @@ For example to horizontally flip the video in input with ffmpeg -i in.avi -vf "hflip" out.avi @end example +@section hqdn3d + +High precision/quality 3d denoise filter. This filter aims to reduce +image noise producing smooth images and making still images really +still. It should enhance compressibility. + +It accepts the following optional parameters: +@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp} + +@table @option +@item luma_spatial +a non-negative float number which specifies spatial luma strength, +defaults to 4.0 + +@item chroma_spatial +a non-negative float number which specifies spatial chroma strength, +defaults to 3.0*@var{luma_spatial}/4.0 + +@item luma_tmp +a float number which specifies luma temporal strength, defaults to +6.0*@var{luma_spatial}/4.0 + +@item chroma_tmp +a float number which specifies chroma temporal strength, defaults to +@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} +@end table + @section noformat Force libavfilter not to use any of the specified pixel formats for the @@ -284,27 +709,100 @@ input to the next filter. The filter accepts a list of pixel format names, separated by ":", for example "yuv420p:monow:rgb24". -The following command: - +Some examples follow: @example -./ffmpeg -i in.avi -vf "noformat=yuv420p, vflip" out.avi -@end example +# force libavfilter to use a format different from "yuv420p" for the +# input to the vflip filter +noformat=yuv420p,vflip -will make libavfilter use a format different from "yuv420p" for the -input to the vflip filter. +# convert the input video to any of the formats not contained in the list +noformat=yuv420p:yuv444p:yuv410p +@end example @section null Pass the video source unchanged to the output. -@section ocv_smooth +@section ocv -Apply smooth transform using libopencv. +Apply video transform using libopencv. To enable this filter install libopencv library and headers and -configure FFmpeg with --enable-libopencv. +configure Libav with --enable-libopencv. + +The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}. + +@var{filter_name} is the name of the libopencv filter to apply. + +@var{filter_params} specifies the parameters to pass to the libopencv +filter. If not specified the default values are assumed. + +Refer to the official libopencv documentation for more precise +informations: +@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} + +Follows the list of supported libopencv filters. -The filter accepts the following parameters: +@anchor{dilate} +@subsection dilate + +Dilate an image by using a specific structuring element. +This filter corresponds to the libopencv function @code{cvDilate}. + +It accepts the parameters: @var{struct_el}:@var{nb_iterations}. + +@var{struct_el} represents a structuring element, and has the syntax: +@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape} + +@var{cols} and @var{rows} represent the number of colums and rows of +the structuring element, @var{anchor_x} and @var{anchor_y} the anchor +point, and @var{shape} the shape for the structuring element, and +can be one of the values "rect", "cross", "ellipse", "custom". + +If the value for @var{shape} is "custom", it must be followed by a +string of the form "=@var{filename}". The file with name +@var{filename} is assumed to represent a binary image, with each +printable character corresponding to a bright pixel. When a custom +@var{shape} is used, @var{cols} and @var{rows} are ignored, the number +or columns and rows of the read file are assumed instead. + +The default value for @var{struct_el} is "3x3+0x0/rect". + +@var{nb_iterations} specifies the number of times the transform is +applied to the image, and defaults to 1. + +Follow some example: +@example +# use the default values +ocv=dilate + +# dilate using a structuring element with a 5x5 cross, iterate two times +ocv=dilate=5x5+2x2/cross:2 + +# read the shape from the file diamond.shape, iterate two times +# the file diamond.shape may contain a pattern of characters like this: +# * +# *** +# ***** +# *** +# * +# the specified cols and rows are ignored (but not the anchor point coordinates) +ocv=0x0+2x2/custom=diamond.shape:2 +@end example + +@subsection erode + +Erode an image by using a specific structuring element. +This filter corresponds to the libopencv function @code{cvErode}. + +The filter accepts the parameters: @var{struct_el}:@var{nb_iterations}, +with the same syntax and semantics as the @ref{dilate} filter. + +@subsection smooth + +Smooth the input video. + +The filter takes the following parameters: @var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}. @var{type} is the type of smooth filter to apply, and can be one of @@ -320,9 +818,65 @@ The default value for @var{param1} is 3, the default value for the other parameters is 0. These parameters correspond to the parameters assigned to the -libopencv function @code{cvSmooth}. Refer to the official libopencv -documentation for the exact meaning of the parameters: -@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} +libopencv function @code{cvSmooth}. + +@section overlay + +Overlay one video on top of another. + +It takes two inputs and one output, the first input is the "main" +video on which the second input is overlayed. + +It accepts the parameters: @var{x}:@var{y}. + +@var{x} is the x coordinate of the overlayed video on the main video, +@var{y} is the y coordinate. The parameters are expressions containing +the following parameters: + +@table @option +@item main_w, main_h +main input width and height + +@item W, H +same as @var{main_w} and @var{main_h} + +@item overlay_w, overlay_h +overlay input width and height + +@item w, h +same as @var{overlay_w} and @var{overlay_h} +@end table + +Be aware that frames are taken from each input video in timestamp +order, hence, if their initial timestamps differ, it is a a good idea +to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to +have them begin in the same zero timestamp, as it does the example for +the @var{movie} filter. + +Follow some examples: +@example +# draw the overlay at 10 pixels from the bottom right +# corner of the main video. +overlay=main_w-overlay_w-10:main_h-overlay_h-10 + +# insert a transparent PNG logo in the bottom left corner of the input +movie=logo.png [logo]; +[in][logo] overlay=10:main_h-overlay_h-10 [out] + +# insert 2 different transparent PNG logos (second logo on bottom +# right corner): +movie=logo1.png [logo1]; +movie=logo2.png [logo2]; +[in][logo1] overlay=10:H-h-10 [in+logo1]; +[in+logo1][logo2] overlay=W-w-10:H-h-10 [out] + +# add a transparent color layer on top of the main video, +# WxH specifies the size of the main input to the overlay filter +color=red@.3:WxH [over]; [in][over] overlay [out] +@end example + +You can chain togheter more overlays but the efficiency of such +approach is yet to be tested. @section pad @@ -332,6 +886,39 @@ given coordinates @var{x}, @var{y}. It accepts the following parameters: @var{width}:@var{height}:@var{x}:@var{y}:@var{color}. +The parameters @var{width}, @var{height}, @var{x}, and @var{y} are +expressions containing the following constants: + +@table @option +@item E, PI, PHI +the corresponding mathematical approximated values for e +(euler number), pi (greek PI), phi (golden ratio) + +@item in_w, in_h +the input video width and heigth + +@item iw, ih +same as @var{in_w} and @var{in_h} + +@item out_w, out_h +the output width and heigth, that is the size of the padded area as +specified by the @var{width} and @var{height} expressions + +@item ow, oh +same as @var{out_w} and @var{out_h} + +@item x, y +x and y offsets as specified by the @var{x} and @var{y} +expressions, or NAN if not yet specified + +@item a +input display aspect ratio, same as @var{iw} / @var{ih} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@end table + Follows the description of the accepted parameters. @table @option @@ -341,6 +928,9 @@ Specify the size of the output image with the paddings added. If the value for @var{width} or @var{height} is 0, the corresponding input size is used for the output. +The @var{width} expression can reference the value set by the +@var{height} expression, and viceversa. + The default value of @var{width} and @var{height} is 0. @item x, y @@ -348,6 +938,9 @@ The default value of @var{width} and @var{height} is 0. Specify the offsets where to place the input image in the padded area with respect to the top/left border of the output image. +The @var{x} expression can reference the value set by the @var{y} +expression, and viceversa. + The default value of @var{x} and @var{y} is 0. @item color @@ -359,6 +952,31 @@ The default value of @var{color} is "black". @end table +Some examples follow: + +@example +# Add paddings with color "violet" to the input video. Output video +# size is 640x480, the top-left corner of the input video is placed at +# column 0, row 40. +pad=640:480:0:40:violet + +# pad the input to get an output with dimensions increased bt 3/2, +# and put the input video at the center of the padded area +pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2" + +# pad the input to get a squared output with size equal to the maximum +# value between the input width and height, and put the input video at +# the center of the padded area +pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2" + +# pad the input to get a final w/h ratio of 16:9 +pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" + +# double output size and put the input video in the bottom-right +# corner of the output padded area +pad="2*iw:2*ih:ow-iw:oh-ih" +@end example + @section pixdesctest Pixel format descriptor test filter, mainly useful for internal @@ -375,13 +993,33 @@ can be used to test the monowhite pixel format descriptor definition. Scale the input video to @var{width}:@var{height} and/or convert the image format. -For example the command: +The parameters @var{width} and @var{height} are expressions containing +the following constants: -@example -./ffmpeg -i in.avi -vf "scale=200:100" out.avi -@end example +@table @option +@item E, PI, PHI +the corresponding mathematical approximated values for e +(euler number), pi (greek PI), phi (golden ratio) + +@item in_w, in_h +the input width and heigth + +@item iw, ih +same as @var{in_w} and @var{in_h} + +@item out_w, out_h +the output (cropped) width and heigth + +@item ow, oh +same as @var{out_w} and @var{out_h} + +@item a +input display aspect ratio, same as @var{iw} / @var{ih} -will scale the input video to a size of 200x100. +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@end table If the input image format is different from the format requested by the next filter, the scale filter will convert the input to the @@ -396,6 +1034,241 @@ ratio of the input image. The default value of @var{width} and @var{height} is 0. +Some examples follow: +@example +# scale the input video to a size of 200x100. +scale=200:100 + +# scale the input to 2x +scale=2*iw:2*ih +# the above is the same as +scale=2*in_w:2*in_h + +# scale the input to half size +scale=iw/2:ih/2 + +# increase the width, and set the height to the same size +scale=3/2*iw:ow + +# seek for Greek harmony +scale=iw:1/PHI*iw +scale=ih*PHI:ih + +# increase the height, and set the width to 3/2 of the height +scale=3/2*oh:3/5*ih + +# increase the size, but make the size a multiple of the chroma +scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub" + +# increase the width to a maximum of 500 pixels, keep the same input aspect ratio +scale='min(500\, iw*3/2):-1' +@end example + +@anchor{setdar} +@section setdar + +Set the Display Aspect Ratio for the filter output video. + +This is done by changing the specified Sample (aka Pixel) Aspect +Ratio, according to the following equation: +@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} + +Keep in mind that this filter does not modify the pixel dimensions of +the video frame. Also the display aspect ratio set by this filter may +be changed by later filters in the filterchain, e.g. in case of +scaling or if another "setdar" or a "setsar" filter is applied. + +The filter accepts a parameter string which represents the wanted +display aspect ratio. +The parameter can be a floating point number string, or an expression +of the form @var{num}:@var{den}, where @var{num} and @var{den} are the +numerator and denominator of the aspect ratio. +If the parameter is not specified, it is assumed the value "0:1". + +For example to change the display aspect ratio to 16:9, specify: +@example +setdar=16:9 +# the above is equivalent to +setdar=1.77777 +@end example + +See also the @ref{setsar} filter documentation. + +@section setpts + +Change the PTS (presentation timestamp) of the input video frames. + +Accept in input an expression evaluated through the eval API, which +can contain the following constants: + +@table @option +@item PTS +the presentation timestamp in input + +@item PI +Greek PI + +@item PHI +golden ratio + +@item E +Euler number + +@item N +the count of the input frame, starting from 0. + +@item STARTPTS +the PTS of the first video frame + +@item INTERLACED +tell if the current frame is interlaced + +@item POS +original position in the file of the frame, or undefined if undefined +for the current frame + +@item PREV_INPTS +previous input PTS + +@item PREV_OUTPTS +previous output PTS + +@end table + +Some examples follow: + +@example +# start counting PTS from zero +setpts=PTS-STARTPTS + +# fast motion +setpts=0.5*PTS + +# slow motion +setpts=2.0*PTS + +# fixed rate 25 fps +setpts=N/(25*TB) + +# fixed rate 25 fps with some jitter +setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' +@end example + +@anchor{setsar} +@section setsar + +Set the Sample (aka Pixel) Aspect Ratio for the filter output video. + +Note that as a consequence of the application of this filter, the +output display aspect ratio will change according to the following +equation: +@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} + +Keep in mind that the sample aspect ratio set by this filter may be +changed by later filters in the filterchain, e.g. if another "setsar" +or a "setdar" filter is applied. + +The filter accepts a parameter string which represents the wanted +sample aspect ratio. +The parameter can be a floating point number string, or an expression +of the form @var{num}:@var{den}, where @var{num} and @var{den} are the +numerator and denominator of the aspect ratio. +If the parameter is not specified, it is assumed the value "0:1". + +For example to change the sample aspect ratio to 10:11, specify: +@example +setsar=10:11 +@end example + +@section settb + +Set the timebase to use for the output frames timestamps. +It is mainly useful for testing timebase configuration. + +It accepts in input an arithmetic expression representing a rational. +The expression can contain the constants "PI", "E", "PHI", "AVTB" (the +default timebase), and "intb" (the input timebase). + +The default value for the input is "intb". + +Follow some examples. + +@example +# set the timebase to 1/25 +settb=1/25 + +# set the timebase to 1/10 +settb=0.1 + +#set the timebase to 1001/1000 +settb=1+0.001 + +#set the timebase to 2*intb +settb=2*intb + +#set the default timebase value +settb=AVTB +@end example + +@section showinfo + +Show a line containing various information for each input video frame. +The input video is not modified. + +The shown line contains a sequence of key/value pairs of the form +@var{key}:@var{value}. + +A description of each shown parameter follows: + +@table @option +@item n +sequential number of the input frame, starting from 0 + +@item pts +Presentation TimeStamp of the input frame, expressed as a number of +time base units. The time base unit depends on the filter input pad. + +@item pts_time +Presentation TimeStamp of the input frame, expressed as a number of +seconds + +@item pos +position of the frame in the input stream, -1 if this information in +unavailable and/or meanigless (for example in case of synthetic video) + +@item fmt +pixel format name + +@item sar +sample aspect ratio of the input frame, expressed in the form +@var{num}/@var{den} + +@item s +size of the input frame, expressed in the form +@var{width}x@var{height} + +@item i +interlaced mode ("P" for "progressive", "T" for top field first, "B" +for bottom field first) + +@item iskey +1 if the frame is a key frame, 0 otherwise + +@item type +picture type of the input frame ("I" for an I-frame, "P" for a +P-frame, "B" for a B-frame, "?" for unknown type). +Check also the documentation of the @code{AVPictureType} enum and of +the @code{av_get_picture_type_char} function defined in +@file{libavutil/avutil.h}. + +@item checksum +Adler-32 checksum of all the planes of the input frame + +@item plane_checksum +Adler-32 checksum of each plane of the input frame, expressed in the form +"[@var{c0} @var{c1} @var{c2} @var{c3}]" +@end table + @section slicify Pass the images of input video on to next video filter as multiple @@ -411,6 +1284,47 @@ not specified it will use the default value of 16. Adding this in the beginning of filter chains should make filtering faster due to better use of the memory cache. +@section transpose + +Transpose rows with columns in the input video and optionally flip it. + +It accepts a parameter representing an integer, which can assume the +values: + +@table @samp +@item 0 +Rotate by 90 degrees counterclockwise and vertically flip (default), that is: +@example +L.R L.l +. . -> . . +l.r R.r +@end example + +@item 1 +Rotate by 90 degrees clockwise, that is: +@example +L.R l.L +. . -> . . +l.r r.R +@end example + +@item 2 +Rotate by 90 degrees counterclockwise, that is: +@example +L.R R.r +. . -> . . +l.r L.l +@end example + +@item 3 +Rotate by 90 degrees clockwise and vertically flip, that is: +@example +L.R r.R +. . -> . . +l.r l.L +@end example +@end table + @section unsharp Sharpen or blur the input video. @@ -471,34 +1385,43 @@ Flip the input video vertically. @section yadif -yadif is "yet another deinterlacing filter". +Deinterlace the input video ("yadif" means "yet another deinterlacing +filter"). -It accepts the syntax: -@example -yadif=[@var{mode}[:@var{parity}]] -@end example - -@table @option - -@item mode -Specify the interlacing mode to adopt, accepts one of the following values. - -0: Output 1 frame for each frame. - -1: Output 1 frame for each field. +It accepts the optional parameters: @var{mode}:@var{parity}. -2: Like 0 but skips spatial interlacing check. +@var{mode} specifies the interlacing mode to adopt, accepts one of the +following values: -3: Like 1 but skips spatial interlacing check. +@table @option +@item 0 +output 1 frame for each frame +@item 1 +output 1 frame for each field +@item 2 +like 0 but skips spatial interlacing check +@item 3 +like 1 but skips spatial interlacing check +@end table Default value is 0. -@item parity -0 if is bottom field first, 1 if the interlaced video is top field -first, -1 to enable automatic detection. +@var{parity} specifies the picture field parity assumed for the input +interlaced video, accepts one of the following values: +@table @option +@item 0 +assume bottom field first +@item 1 +assume top field first +@item -1 +enable automatic detection @end table +Default value is -1. +If interlacing is unknown or decoder does not export this information, +top field first will be assumed. + @c man end VIDEO FILTERS @chapter Video Sources @@ -514,7 +1437,7 @@ This source is mainly intended for a programmatic use, in particular through the interface defined in @file{libavfilter/vsrc_buffer.h}. It accepts the following parameters: -@var{width}:@var{height}:@var{pix_fmt_string} +@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den} All the parameters need to be explicitely defined. @@ -526,24 +1449,32 @@ Follows the list of the accepted parameters. Specify the width and height of the buffered video frames. @item pix_fmt_string - A string representing the pixel format of the buffered video frames. It may be a number corresponding to a pixel format, or a pixel format name. +@item timebase_num, timebase_den +Specify numerator and denomitor of the timebase assumed by the +timestamps of the buffered frames. + +@item sample_aspect_ratio.num, sample_aspect_ratio.den +Specify numerator and denominator of the sample aspect ratio assumed +by the video frames. @end table For example: @example -buffer=320:240:yuv410p +buffer=320:240:yuv410p:1:24:1:1 @end example will instruct the source to accept video frames with size 320x240 and -with format "yuv410p". Since the pixel format with name "yuv410p" -corresponds to the number 6 (check the enum PixelFormat definition in -@file{libavutil/pixfmt.h}), this example corresponds to: +with format "yuv410p", assuming 1/24 as the timestamps timebase and +square pixels (1:1 sample aspect ratio). +Since the pixel format with name "yuv410p" corresponds to the number 6 +(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}), +this example corresponds to: @example -buffer=320:240:6 +buffer=320:240:6:1:24 @end example @section color @@ -585,17 +1516,103 @@ to the pad with identifier "in". "color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]" @end example +@section movie + +Read a video stream from a movie container. + +It accepts the syntax: @var{movie_name}[:@var{options}] where +@var{movie_name} is the name of the resource to read (not necessarily +a file but also a device or a stream accessed through some protocol), +and @var{options} is an optional sequence of @var{key}=@var{value} +pairs, separated by ":". + +The description of the accepted options follows. + +@table @option + +@item format_name, f +Specifies the format assumed for the movie to read, and can be either +the name of a container or an input device. If not specified the +format is guessed from @var{movie_name} or by probing. + +@item seek_point, sp +Specifies the seek point in seconds, the frames will be output +starting from this seek point, the parameter is evaluated with +@code{av_strtod} so the numerical value may be suffixed by an IS +postfix. Default value is "0". + +@item stream_index, si +Specifies the index of the video stream to read. If the value is -1, +the best suited video stream will be automatically selected. Default +value is "-1". + +@end table + +This filter allows to overlay a second video on top of main input of +a filtergraph as shown in this graph: +@example +input -----------> deltapts0 --> overlay --> output + ^ + | +movie --> scale--> deltapts1 -------+ +@end example + +Some examples follow: +@example +# skip 3.2 seconds from the start of the avi file in.avi, and overlay it +# on top of the input labelled as "in". +movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; +[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] + +# read from a video4linux2 device, and overlay it on top of the input +# labelled as "in" +movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; +[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] + +@end example + @section nullsrc Null video source, never return images. It is mainly useful as a template and to be employed in analysis / debugging tools. It accepts as optional parameter a string of the form -@var{width}:@var{height}, where @var{width} and @var{height} specify the size of -the configured source. +@var{width}:@var{height}:@var{timebase}. + +@var{width} and @var{height} specify the size of the configured +source. The default values of @var{width} and @var{height} are +respectively 352 and 288 (corresponding to the CIF size format). + +@var{timebase} specifies an arithmetic expression representing a +timebase. The expression can contain the constants "PI", "E", "PHI", +"AVTB" (the default timebase), and defaults to the value "AVTB". -The default values of @var{width} and @var{height} are respectively 352 -and 288 (corresponding to the CIF size format). +@section frei0r_src + +Provide a frei0r source. + +To enable compilation of this filter you need to install the frei0r +header and configure Libav with --enable-frei0r. + +The source supports the syntax: +@example +@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}] +@end example + +@var{size} is the size of the video to generate, may be a string of the +form @var{width}x@var{height} or a frame size abbreviation. +@var{rate} is the rate of the video to generate, may be a string of +the form @var{num}/@var{den} or a frame rate abbreviation. +@var{src_name} is the name to the frei0r source to load. For more +information regarding frei0r and how to set the parameters read the +section @ref{frei0r} in the description of the video filters. + +Some examples follow: +@example +# generate a frei0r partik0l source with size 200x200 and framerate 10 +# which is overlayed on the overlay filter main input +frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay +@end example @c man end VIDEO SOURCES