ffmpeg/doc/muxers.texi

@chapter Muxers
@c man begin MUXERS

Muxers are configured elements in FFmpeg which allow writing
multimedia streams to a particular type of file.

When you configure your FFmpeg build, all the supported muxers
are enabled by default. You can list all available muxers using the
configure option @code{--list-muxers}.

You can disable all the muxers with the configure option
@code{--disable-muxers} and selectively enable / disable single muxers
with the options @code{--enable-muxer=@var{MUXER}} /
@code{--disable-muxer=@var{MUXER}}.

The option @code{-formats} of the ff* tools will display the list of
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