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@chapter Demuxers
@c man begin DEMUXERS

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

When you configure your Libav build, all the supported demuxers
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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
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enabled demuxers.

The description of some of the currently available demuxers follows.

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@section image2

Image file demuxer.

This demuxer reads from a list of image files specified by a pattern.

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The pattern may contain the string "%d" or "%0@var{N}d", which
specifies the position of the characters representing a sequential
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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 "%%".

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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.
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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
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video from the images in the file sequence @file{img-001.jpeg},
@file{img-002.jpeg}, ..., assuming an input framerate of 10 frames per
avconv -i 'img-%03d.jpeg' -r 10 out.mkv
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@end example

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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:
avconv -i img.jpeg img.png
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@end example

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@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

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@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
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the discard flags on AVStreams (by pressing 'a' or 'v' in avplay),
the caller can decide which variant streams to actually receive.
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The total bitrate of the variant that the stream belongs to is
available in a metadata key named "variant_bitrate".

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@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}
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Allocate the streams according to the onMetaData array content.
@end table

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@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