Add documentation for the image2 muxer.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
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Stefano Sabatini 2011-01-26 22:53:00 +01:00 committed by Ronald S. Bultje
parent 22e9277aa5
commit e771d2e3fe

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@ -18,4 +18,54 @@ enabled muxers.
A description of some of the currently available muxers follows.
@section image2
Image file muxer.
This muxer writes video frames to multiple image files specified by a
pattern.
The pattern may contain the string "%d" or "%0@var{N}d", which
specifies the position of the characters representing a numbering in
the filenames. If the form "%d0@var{N}d" is used, the string
representing the number in each filename is 0-padded to @var{N}
digits. The literal character '%' can be specified in the pattern with
the string "%%".
If the pattern contains "%d" or "%0@var{N}d", the first filename of
the file list specified will contain the number 1, all the following
numbers will be sequential.
The pattern may contain a suffix which is used to automatically
determine the format of the image files to write.
For example the pattern "img-%03d.bmp" will specify a sequence of
filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
@file{img-010.bmp}, etc.
The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
etc.
The following example shows how to use @file{ffmpeg} for creating a
sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
taking one image every second from the input video:
@example
ffmpeg -i in.avi -r 1 -f image2 'img-%03d.jpeg'
@end example
Note that with @file{ffmpeg}, if the format is not specified with the
@code{-f} option and the output filename specifies an image file
format, the image2 muxer is automatically selected, so the previous
command can be written as:
@example
ffmpeg -i in.avi -r 1 'img-%03d.jpeg'
@end example
Note also that the pattern must not necessarily contain "%d" or
"%0@var{N}d", for example to create a single image file
@file{img.jpeg} from the input video you can employ the command:
@example
ffmpeg -i in.avi -f image2 -vframes 1 img.jpeg
@end example
@c man end MUXERS