Commit d4a8a86c authored by Katerina Barone-Adesi's avatar Katerina Barone-Adesi Committed by Luca Barbato

doc: Libavfilter English cleanup

This aims to standardize the English used in the libavfilter
documentation, describing the same thing in the same way more often,
and significantly reduce the amount of outright errors, including
run-on sentences and sentence fragments.
Signed-off-by: 's avatarLuca Barbato <lu_zero@gentoo.org>
parent 617a1a98
This diff is collapsed.
......@@ -11,10 +11,10 @@
@chapter Introduction
Libavfilter is the filtering API of Libav. It is the substitute of the
now deprecated 'vhooks' and started as a Google Summer of Code project.
Libavfilter is the filtering API of Libav. It replaces 'vhooks', and
started as a Google Summer of Code project.
But note that there may still be serious bugs in the code and its API
Note that there may still be serious bugs in the code and its API
and ABI should not be considered stable yet!
@chapter Tutorial
......@@ -31,33 +31,33 @@ input --> split --> fifo -----------------------> overlay --> output
+------> fifo --> crop --> vflip --------+
@end example
splits the stream in two streams, sends one stream through the crop filter
and the vflip filter before merging it back with the other stream by
splits the stream in two streams, then sends one stream through the crop filter
and the vflip filter, before merging it back with the other stream by
overlaying it on top. You can use the following command to achieve this:
@example
./avconv -i input -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, vflip [T2]" output
@end example
The result will be that in output the top half of the video is mirrored
onto the bottom half.
The result will be that the top half of the video is mirrored
onto the bottom half of the output video.
Video filters are loaded using the @var{-vf} option passed to
avconv or to avplay. Filters in the same linear chain are separated by
commas. In our example, @var{split, fifo, overlay} are in one linear
chain, and @var{fifo, crop, vflip} are in another. The points where
the linear chains join are labeled by names enclosed in square
brackets. In our example, that is @var{[T1]} and @var{[T2]}. The magic
commas. In our example, @var{split}, @var{fifo}, and @var{overlay} are in one
linear chain, and @var{fifo}, @var{crop}, and @var{vflip} are in another. The
points where the linear chains join are labeled by names enclosed in square
brackets. In our example, they join at @var{[T1]} and @var{[T2]}. The magic
labels @var{[in]} and @var{[out]} are the points where video is input
and output.
Some filters take in input a list of parameters: they are specified
after the filter name and an equal sign, and are separated each other
Some filters take a list of parameters: they are specified
after the filter name and an equal sign, and are separated
by a semicolon.
There exist so-called @var{source filters} that do not have a video
input, and we expect in the future some @var{sink filters} that will
not have video output.
There are so-called @var{source filters} that do not take video
input, and we expect that some @var{sink filters} will
not have video output, at some point in the future.
@chapter graph2dot
......
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