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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/filters.texi | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index e4aa9921c0..f96a10a75e 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -5251,22 +5251,36 @@ Swap U & V plane. @section thumbnail Select the most representative frame in a given sequence of consecutive frames. -It accepts as argument the frames batch size to analyze (default @var{N}=100); -in a set of @var{N} frames, the filter will pick one of them, and then handle -the next batch of @var{N} frames until the end. +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +thumbnail[=@var{n}]. + +@table @option +@item n +Set the frames batch size to analyze; in a set of @var{n} frames, the filter +will pick one of them, and then handle the next batch of @var{n} frames until +the end. Default is @code{100}. +@end table -Since the filter keeps track of the whole frames sequence, a bigger @var{N} +Since the filter keeps track of the whole frames sequence, a bigger @var{n} value will result in a higher memory usage, so a high value is not recommended. -The following example extract one picture each 50 frames: +@subsection Examples + +@itemize +@item +Extract one picture each 50 frames: @example thumbnail=50 @end example +@item Complete example of a thumbnail creation with @command{ffmpeg}: @example ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png @end example +@end itemize @section tile |