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author | Stefano Sabatini <stefasab@gmail.com> | 2012-08-21 14:34:10 +0400 |
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committer | Stefano Sabatini <stefasab@gmail.com> | 2012-08-22 03:03:42 +0400 |
commit | 4a32b30e0cd906523564e77e6db2f92aca37a10c (patch) | |
tree | 8e4f06ed5e5e9e9a4098485f8e3be6598dd33a32 /doc | |
parent | bc151aee60f0d108749d4cb85550067ee2840dc3 (diff) |
doc/filters: itemize examples for pad filter, and fix a few typos
Diffstat (limited to 'doc')
-rw-r--r-- | doc/filters.texi | 55 |
1 files changed, 39 insertions, 16 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index a9dbaf58b7..41f2d224ee 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -2795,36 +2795,59 @@ The default value of @var{color} is "black". @end table -Some examples follow: +@section Examples +@itemize +@item +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: @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 +@end example -# 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 +@item +Pad the input to get an output with dimensions increased by 3/2, +and put the input video at the center of the padded area: +@example pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2" +@end example -# 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 +@item +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: +@example pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2" +@end example -# pad the input to get a final w/h ratio of 16:9 +@item +Pad the input to get a final w/h ratio of 16:9: +@example pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +In case of anamorphic video, in order to set the output display aspect +correctly, it is necessary to use @var{sar} in the expression, +according to the relation: +@example +(ih * X / ih) * sar = output_dar +X = output_dar / sar +@end example -# for anamorphic video, in order to set the output display aspect ratio, -# it is necessary to use sar in the expression, according to the relation: -# (ih * X / ih) * sar = output_dar -# X = output_dar / sar +Thus the previous example needs to be modified to: +@example pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2" +@end example -# double output size and put the input video in the bottom-right -# corner of the output padded area +@item +Double output size and put the input video in the bottom-right +corner of the output padded area: +@example pad="2*iw:2*ih:ow-iw:oh-ih" @end example +@end itemize @section pixdesctest |