Add documentation for the image2 muxer.
[libav.git] / doc / muxers.texi
1 @chapter Muxers
2 @c man begin MUXERS
4 Muxers are configured elements in FFmpeg which allow writing
5 multimedia streams to a particular type of file.
7 When you configure your FFmpeg build, all the supported muxers
8 are enabled by default. You can list all available muxers using the
9 configure option @code{--list-muxers}.
11 You can disable all the muxers with the configure option
12 @code{--disable-muxers} and selectively enable / disable single muxers
13 with the options @code{--enable-muxer=@var{MUXER}} /
14 @code{--disable-muxer=@var{MUXER}}.
16 The option @code{-formats} of the ff* tools will display the list of
17 enabled muxers.
19 A description of some of the currently available muxers follows.
21 @section image2
23 Image file muxer.
25 This muxer writes video frames to multiple image files specified by a
26 pattern.
28 The pattern may contain the string "%d" or "%0@var{N}d", which
29 specifies the position of the characters representing a numbering in
30 the filenames. If the form "%d0@var{N}d" is used, the string
31 representing the number in each filename is 0-padded to @var{N}
32 digits. The literal character '%' can be specified in the pattern with
33 the string "%%".
35 If the pattern contains "%d" or "%0@var{N}d", the first filename of
36 the file list specified will contain the number 1, all the following
37 numbers will be sequential.
39 The pattern may contain a suffix which is used to automatically
40 determine the format of the image files to write.
42 For example the pattern "img-%03d.bmp" will specify a sequence of
43 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
44 @file{img-010.bmp}, etc.
45 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
46 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
47 etc.
49 The following example shows how to use @file{ffmpeg} for creating a
50 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
51 taking one image every second from the input video:
52 @example
53 ffmpeg -i in.avi -r 1 -f image2 'img-%03d.jpeg'
54 @end example
56 Note that with @file{ffmpeg}, if the format is not specified with the
57 @code{-f} option and the output filename specifies an image file
58 format, the image2 muxer is automatically selected, so the previous
59 command can be written as:
60 @example
61 ffmpeg -i in.avi -r 1 'img-%03d.jpeg'
62 @end example
64 Note also that the pattern must not necessarily contain "%d" or
65 "%0@var{N}d", for example to create a single image file
66 @file{img.jpeg} from the input video you can employ the command:
67 @example
68 ffmpeg -i in.avi -f image2 -vframes 1 img.jpeg
69 @end example
71 @c man end MUXERS