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449 lines
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449 lines
12 KiB
@chapter Audio Filters |
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@c man begin AUDIO FILTERS |
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When you configure your FFmpeg build, you can disable any of the |
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existing filters using --disable-filters. |
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The configure output will show the audio filters included in your |
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build. |
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Below is a description of the currently available audio filters. |
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@section anull |
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Pass the audio source unchanged to the output. |
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@c man end AUDIO FILTERS |
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@chapter Video Filters |
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@c man begin VIDEO FILTERS |
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When you configure your FFmpeg build, you can disable any of the |
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existing filters using --disable-filters. |
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The configure output will show the video filters included in your |
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build. |
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Below is a description of the currently available video filters. |
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@section crop |
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Crop the input video to @var{width}:@var{height}:@var{x}:@var{y}. |
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@example |
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./ffmpeg -i in.avi -vf "crop=0:240:0:0" out.avi |
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@end example |
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The @var{width} and @var{height} parameters specify the width and height |
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of the output (non-cropped) area. |
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A value of 0 is interpreted as the maximum possible size contained in |
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the area delimited by the top-left corner at position x:y. |
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@var{x} and @var{y} specify the position of the top-left corner of the |
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output (non-cropped) area. |
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The default value of @var{x} and @var{y} is 0. |
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For example the parameters: |
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@example |
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"crop=0:0:100:100" |
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@end example |
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will delimit the rectangle with the top-left corner placed at position |
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100:100 and the right-bottom corner corresponding to the right-bottom |
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corner of the input image. |
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The default value of @var{width} and @var{height} is 0. |
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@section fifo |
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Buffer input images and send them when they are requested. |
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This filter is mainly useful when auto-inserted by the libavfilter |
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framework. |
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The filter does not take parameters. |
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@section format |
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Convert the input video to one of the specified pixel formats. |
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Libavfilter will try to pick one that is supported for the input to |
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the next filter. |
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The filter accepts a list of pixel format names, separated by ":", |
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for example "yuv420p:monow:rgb24". |
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The following command: |
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@example |
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./ffmpeg -i in.avi -vf "format=yuv420p" out.avi |
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@end example |
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will convert the input video to the format "yuv420p". |
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@section frei0r |
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Apply a frei0r effect to the input video. |
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To enable compilation of this filter you need to install the frei0r |
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header and configure FFmpeg with --enable-frei0r. |
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The filter supports the syntax: |
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@example |
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@var{filter_name}:@var{param1}:@var{param2}:...:@var{paramN} |
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@end example |
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@var{filter_name} is the name to the frei0r effect to load. If the |
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environment variable @env{FREI0R_PATH} is defined, the frei0r effect |
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is searched in each one of the directories specified by the colon |
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separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r |
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paths, which are in this order: @file{HOME/.frei0r-1/lib/}, |
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@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}. |
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@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters |
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for the frei0r effect. |
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A frei0r effect parameter can be a boolean (whose values are specified |
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with "y" and "n"), a double, a color (specified by the syntax |
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@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float |
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numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color |
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description), a position (specified by the syntax @var{X}/@var{Y}, |
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@var{X} and @var{Y} being float numbers) and a string. |
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The number and kind of parameters depend on the loaded effect. If an |
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effect parameter is not specified the default value is set. |
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Some examples follow: |
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@example |
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# apply the distort0r effect, set the first two double parameters |
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frei0r=distort0r:0.5:0.01 |
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# apply the colordistance effect, takes a color as first parameter |
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frei0r=colordistance:0.2/0.3/0.4 |
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frei0r=colordistance:violet |
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frei0r=colordistance:0x112233 |
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# apply the perspective effect, specify the top left and top right |
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# image positions |
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frei0r=perspective:0.2/0.2:0.8/0.2 |
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@end example |
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For more information see: |
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@url{http://piksel.org/frei0r} |
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@section hflip |
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Flip the input video horizontally. |
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For example to horizontally flip the video in input with |
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@file{ffmpeg}: |
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@example |
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ffmpeg -i in.avi -vf "hflip" out.avi |
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@end example |
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@section noformat |
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Force libavfilter not to use any of the specified pixel formats for the |
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input to the next filter. |
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The filter accepts a list of pixel format names, separated by ":", |
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for example "yuv420p:monow:rgb24". |
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The following command: |
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@example |
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./ffmpeg -i in.avi -vf "noformat=yuv420p, vflip" out.avi |
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@end example |
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will make libavfilter use a format different from "yuv420p" for the |
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input to the vflip filter. |
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@section null |
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Pass the video source unchanged to the output. |
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@section ocv_smooth |
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Apply smooth transform using libopencv. |
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To enable this filter install libopencv library and headers and |
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configure FFmpeg with --enable-libopencv. |
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The filter accepts the following parameters: |
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@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}. |
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@var{type} is the type of smooth filter to apply, and can be one of |
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the following values: "blur", "blur_no_scale", "median", "gaussian", |
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"bilateral". The default value is "gaussian". |
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@var{param1}, @var{param2}, @var{param3}, and @var{param4} are |
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parameters whose meanings depend on smooth type. @var{param1} and |
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@var{param2} accept integer positive values or 0, @var{param3} and |
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@var{param4} accept float values. |
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The default value for @var{param1} is 3, the default value for the |
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other parameters is 0. |
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These parameters correspond to the parameters assigned to the |
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libopencv function @code{cvSmooth}. Refer to the official libopencv |
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documentation for the exact meaning of the parameters: |
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@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} |
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@section pad |
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Add paddings to the input image, and places the original input at the |
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given coordinates @var{x}, @var{y}. |
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It accepts the following parameters: |
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@var{width}:@var{height}:@var{x}:@var{y}:@var{color}. |
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Follows the description of the accepted parameters. |
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@table @option |
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@item width, height |
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Specify the size of the output image with the paddings added. If the |
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value for @var{width} or @var{height} is 0, the corresponding input size |
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is used for the output. |
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The default value of @var{width} and @var{height} is 0. |
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@item x, y |
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Specify the offsets where to place the input image in the padded area |
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with respect to the top/left border of the output image. |
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The default value of @var{x} and @var{y} is 0. |
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@item color |
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Specify the color of the padded area, it can be the name of a color |
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(case insensitive match) or a 0xRRGGBB[AA] sequence. |
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The default value of @var{color} is "black". |
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@end table |
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@section pixdesctest |
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Pixel format descriptor test filter, mainly useful for internal |
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testing. The output video should be equal to the input video. |
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For example: |
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@example |
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format=monow, pixdesctest |
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@end example |
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can be used to test the monowhite pixel format descriptor definition. |
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@section scale |
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Scale the input video to @var{width}:@var{height} and/or convert the image format. |
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For example the command: |
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@example |
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./ffmpeg -i in.avi -vf "scale=200:100" out.avi |
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@end example |
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will scale the input video to a size of 200x100. |
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If the input image format is different from the format requested by |
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the next filter, the scale filter will convert the input to the |
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requested format. |
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If the value for @var{width} or @var{height} is 0, the respective input |
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size is used for the output. |
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If the value for @var{width} or @var{height} is -1, the scale filter will |
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use, for the respective output size, a value that maintains the aspect |
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ratio of the input image. |
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The default value of @var{width} and @var{height} is 0. |
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@section slicify |
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Pass the images of input video on to next video filter as multiple |
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slices. |
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@example |
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./ffmpeg -i in.avi -vf "slicify=32" out.avi |
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@end example |
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The filter accepts the slice height as parameter. If the parameter is |
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not specified it will use the default value of 16. |
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Adding this in the beginning of filter chains should make filtering |
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faster due to better use of the memory cache. |
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@section unsharp |
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Sharpen or blur the input video. |
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It accepts the following parameters: |
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@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount} |
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Negative values for the amount will blur the input video, while positive |
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values will sharpen. All parameters are optional and default to the |
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equivalent of the string '5:5:1.0:0:0:0.0'. |
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@table @option |
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@item luma_msize_x |
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Set the luma matrix horizontal size. It can be an integer between 3 |
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and 13, default value is 5. |
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@item luma_msize_y |
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Set the luma matrix vertical size. It can be an integer between 3 |
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and 13, default value is 5. |
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@item luma_amount |
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Set the luma effect strength. It can be a float number between -2.0 |
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and 5.0, default value is 1.0. |
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@item chroma_msize_x |
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Set the chroma matrix horizontal size. It can be an integer between 3 |
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and 13, default value is 0. |
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@item chroma_msize_y |
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Set the chroma matrix vertical size. It can be an integer between 3 |
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and 13, default value is 0. |
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@item luma_amount |
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Set the chroma effect strength. It can be a float number between -2.0 |
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and 5.0, default value is 0.0. |
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@end table |
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@example |
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# Strong luma sharpen effect parameters |
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unsharp=7:7:2.5 |
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# Strong blur of both luma and chroma parameters |
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unsharp=7:7:-2:7:7:-2 |
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# Use the default values with @command{ffmpeg} |
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./ffmpeg -i in.avi -vf "unsharp" out.mp4 |
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@end example |
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@section vflip |
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Flip the input video vertically. |
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@example |
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./ffmpeg -i in.avi -vf "vflip" out.avi |
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@end example |
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@c man end VIDEO FILTERS |
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@chapter Video Sources |
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@c man begin VIDEO SOURCES |
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Below is a description of the currently available video sources. |
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@section buffer |
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Buffer video frames, and make them available to the filter chain. |
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This source is mainly intended for a programmatic use, in particular |
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through the interface defined in @file{libavfilter/vsrc_buffer.h}. |
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It accepts the following parameters: |
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@var{width}:@var{height}:@var{pix_fmt_string} |
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All the parameters need to be explicitely defined. |
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Follows the list of the accepted parameters. |
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@table @option |
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@item width, height |
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Specify the width and height of the buffered video frames. |
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@item pix_fmt_string |
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A string representing the pixel format of the buffered video frames. |
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It may be a number corresponding to a pixel format, or a pixel format |
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name. |
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@end table |
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For example: |
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@example |
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buffer=320:240:yuv410p |
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@end example |
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will instruct the source to accept video frames with size 320x240 and |
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with format "yuv410p". Since the pixel format with name "yuv410p" |
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corresponds to the number 6 (check the enum PixelFormat definition in |
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@file{libavutil/pixfmt.h}), this example corresponds to: |
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@example |
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buffer=320:240:6 |
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@end example |
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@section color |
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Provide an uniformly colored input. |
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It accepts the following parameters: |
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@var{color}:@var{frame_size}:@var{frame_rate} |
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Follows the description of the accepted parameters. |
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@table @option |
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@item color |
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Specify the color of the source. It can be the name of a color (case |
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insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an |
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alpha specifier. The default value is "black". |
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@item frame_size |
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Specify the size of the sourced video, it may be a string of the form |
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@var{width}x@var{heigth}, or the name of a size abbreviation. The |
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default value is "320x240". |
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@item frame_rate |
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Specify the frame rate of the sourced video, as the number of frames |
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generated per second. It has to be a string in the format |
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@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float |
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number or a valid video frame rate abbreviation. The default value is |
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"25". |
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@end table |
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For example the following graph description will generate a red source |
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with an opacity of 0.2, with size "qcif" and a frame rate of 10 |
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frames per second, which will be overlayed over the source connected |
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to the pad with identifier "in". |
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@example |
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"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]" |
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@end example |
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@section nullsrc |
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Null video source, never return images. It is mainly useful as a |
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template and to be employed in analysis / debugging tools. |
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It accepts as optional parameter a string of the form |
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@var{width}:@var{height}, where @var{width} and @var{height} specify the size of |
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the configured source. |
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The default values of @var{width} and @var{height} are respectively 352 |
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and 288 (corresponding to the CIF size format). |
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@c man end VIDEO SOURCES |
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@chapter Video Sinks |
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@c man begin VIDEO SINKS |
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Below is a description of the currently available video sinks. |
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@section nullsink |
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Null video sink, do absolutely nothing with the input video. It is |
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mainly useful as a template and to be employed in analysis / debugging |
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tools. |
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@c man end VIDEO SINKS |
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