diff options
Diffstat (limited to 'doc/libavfilter.texi')
| -rw-r--r-- | doc/libavfilter.texi | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/doc/libavfilter.texi b/doc/libavfilter.texi index b452294a5f..84bad29dab 100644 --- a/doc/libavfilter.texi +++ b/doc/libavfilter.texi @@ -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 |