@chapter Demuxers
@c man begin DEMUXERS

Demuxers are configured elements in Libav which allow to read the
multimedia streams from a particular type of file.

When you configure your Libav build, all the supported demuxers
are enabled by default. You can list all available ones using the
configure option "--list-demuxers".

You can disable all the demuxers using the configure option
"--disable-demuxers", and selectively enable a single demuxer with
the option "--enable-demuxer=@var{DEMUXER}", or disable it
with the option "--disable-demuxer=@var{DEMUXER}".

The option "-formats" of the av* tools will display the list of
enabled demuxers.

The description of some of the currently available demuxers follows.

@section image2

Image file demuxer.

This demuxer reads from a list of 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 sequential
number in each filename matched by the pattern. If the form
"%d0@var{N}d" is used, the string representing the number in each
filename is 0-padded and @var{N} is the total number of 0-padded
digits representing the number. 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 by the pattern must contain a number
inclusively contained between 0 and 4, all the following numbers must
be sequential. This limitation may be hopefully fixed.

The pattern may contain a suffix which is used to automatically
determine the format of the images contained in the files.

For example the pattern "img-%03d.bmp" will match a sequence of
filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
@file{img-010.bmp}, etc.; the pattern "i%%m%%g-%d.jpg" will match a
sequence of filenames of the form @file{i%m%g-1.jpg},
@file{i%m%g-2.jpg}, ..., @file{i%m%g-10.jpg}, etc.

The size, the pixel format, and the format of each image must be the
same for all the files in the sequence.

The following example shows how to use @command{avconv} for creating a
video from the images in the file sequence @file{img-001.jpeg},
@file{img-002.jpeg}, ..., assuming an input framerate of 10 frames per
second:
@example
avconv -i 'img-%03d.jpeg' -r 10 out.mkv
@end example

Note that the pattern must not necessarily contain "%d" or
"%0@var{N}d", for example to convert a single image file
@file{img.jpeg} you can employ the command:
@example
avconv -i img.jpeg img.png
@end example

@table @option
@item -pixel_format @var{format}
Set the pixel format (for raw image)
@item -video_size   @var{size}
Set the frame size (for raw image)
@item -framerate    @var{rate}
Set the frame rate
@item -loop         @var{bool}
Loop over the images
@item -start_number @var{start}
Specify the first number in the sequence
@end table

@section applehttp

Apple HTTP Live Streaming demuxer.

This demuxer presents all AVStreams from all variant streams.
The id field is set to the bitrate variant index number. By setting
the discard flags on AVStreams (by pressing 'a' or 'v' in avplay),
the caller can decide which variant streams to actually receive.
The total bitrate of the variant that the stream belongs to is
available in a metadata key named "variant_bitrate".

@section flv

Adobe Flash Video Format demuxer.

This demuxer is used to demux FLV files and RTMP network streams.

@table @option
@item -flv_metadata @var{bool}
Allocate the streams according to the onMetaData array content.
@end table

@section asf

Advanced Systems Format demuxer.

This demuxer is used to demux ASF files and MMS network streams.

@table @option
@item -no_resync_search @var{bool}
Do not try to resynchronize by looking for a certain optional start code.
@end table

@c man end INPUT DEVICES