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@chapter Demuxers

@c man begin DEMUXERS

Demuxers are configured elements in FFmpeg that can read the

multimedia streams from a particular type of file.

When you configure your FFmpeg build, all the supported demuxers

are enabled by default. You can list all available ones using the

configure option @code{--list-demuxers}.

You can disable all the demuxers using the configure option

@code{--disable-demuxers}, and selectively enable a single demuxer with

the option @code{--enable-demuxer=@var{DEMUXER}}, or disable it

with the option @code{--disable-demuxer=@var{DEMUXER}}.

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

enabled demuxers.

The description of some of the currently available demuxers follows.

@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 ffplay),

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 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

@anchor{concat}

@section concat

Virtual concatenation script demuxer.

This demuxer reads a list of files and other directives from a text file and

demuxes them one after the other, as if all their packet had been muxed

together.

The timestamps in the files are adjusted so that the first file starts at 0

and each next file starts where the previous one finishes. Note that it is

done globally and may cause gaps if all streams do not have exactly the same

length.

All files must have the same streams (same codecs, same time base, etc.).

The duration of each file is used to adjust the timestamps of the next file:

if the duration is incorrect (because it was computed using the bit-rate or

because the file is truncated, for example), it can cause artifacts. The

@code{duration} directive can be used to override the duration stored in

each file.

@subsection Syntax

The script is a text file in extended-ASCII, with one directive per line.

Empty lines, leading spaces and lines starting with '#' are ignored. The

following directive is recognized:

@table @option

@item @code{file @var{path}}

Path to a file to read; special characters and spaces must be escaped with

backslash or single quotes.

All subsequent directives apply to that file.

@item @code{ffconcat version 1.0}

Identify the script type and version. It also sets the @option{safe} option

to 1 if it was to its default -1.

To make FFmpeg recognize the format automatically, this directive must

appears exactly as is (no extra space or byte-order-mark) on the very first

line of the script.

@item @code{duration @var{dur}}

Duration of the file. This information can be specified from the file;

specifying it here may be more efficient or help if the information from the

file is not available or accurate.

If the duration is set for all files, then it is possible to seek in the

whole concatenated video.

@end table

@subsection Options

This demuxer accepts the following option:

@table @option

@item safe

If set to 1, reject unsafe file paths. A file path is considered safe if it

does not contain a protocol specification and is relative and all components

only contain characters from the portable character set (letters, digits,

period, underscore and hyphen) and have no period at the beginning of a

component.

If set to 0, any file name is accepted.

The default is -1, it is equivalent to 1 if the format was automatically

probed and 0 otherwise.

@end table

@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 libgme

The Game Music Emu library is a collection of video game music file emulators.

See @url{http://code.google.com/p/game-music-emu/} for more information.

Some files have multiple tracks. The demuxer will pick the first track by

default. The @option{track_index} option can be used to select a different

track. Track indexes start at 0. The demuxer exports the number of tracks as

@var{tracks} meta data entry.

For very large files, the @option{max_size} option may have to be adjusted.

@section libquvi

Play media from Internet services using the quvi project.

The demuxer accepts a @option{format} option to request a specific quality. It

is by default set to @var{best}.

See @url{http://quvi.sourceforge.net/} for more information.

FFmpeg needs to be built with @code{--enable-libquvi} for this demuxer to be

enabled.

@section image2

Image file demuxer.

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

The syntax and meaning of the pattern is specified by the

option @var{pattern_type}.

The pattern may contain a suffix which is used to automatically

determine the format of the images contained in the files.

The size, the pixel format, and the format of each image must be the

same for all the files in the sequence.

This demuxer accepts the following options:

@table @option

@item framerate

Set the frame rate for the video stream. It defaults to 25.

@item loop

If set to 1, loop over the input. Default value is 0.

@item pattern_type

Select the pattern type used to interpret the provided filename.

@var{pattern_type} accepts one of the following values.

@table @option

@item sequence

Select a sequence pattern type, used to specify a sequence of files

indexed by sequential numbers.

A sequence 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 sequence 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 @var{start_number} and

@var{start_number}+@var{start_number_range}-1, and all the following

numbers must be sequential.

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.

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

ffmpeg -i img.jpeg img.png

@end example

@item glob

Select a glob wildcard pattern type.

The pattern is interpreted like a @code{glob()} pattern. This is only

selectable if libavformat was compiled with globbing support.

@item glob_sequence @emph{(deprecated, will be removed)}

Select a mixed glob wildcard/sequence pattern.

If your version of libavformat was compiled with globbing support, and

the provided pattern contains at least one glob meta character among

@code{%*?[]@{@}} that is preceded by an unescaped "%", the pattern is

interpreted like a @code{glob()} pattern, otherwise it is interpreted

like a sequence pattern.

All glob special characters @code{%*?[]@{@}} must be prefixed

with "%". To escape a literal "%" you shall use "%%".

For example the pattern @code{foo-%*.jpeg} will match all the

filenames prefixed by "foo-" and terminating with ".jpeg", and

@code{foo-%?%?%?.jpeg} will match all the filenames prefixed with

"foo-", followed by a sequence of three characters, and terminating

with ".jpeg".

This pattern type is deprecated in favor of @var{glob} and

@var{sequence}.

@end table

Default value is @var{glob_sequence}.

@item pixel_format

Set the pixel format of the images to read. If not specified the pixel

format is guessed from the first image file in the sequence.

@item start_number

Set the index of the file matched by the image file pattern to start

to read from. Default value is 0.

@item start_number_range

Set the index interval range to check when looking for the first image

file in the sequence, starting from @var{start_number}. Default value

is 5.

@item ts_from_file

If set to 1, will set frame timestamp to modification time of image file. Note

that monotonity of timestamps is not provided: images go in the same order as

without this option. Default value is 0.

@item video_size

Set the video size of the images to read. If not specified the video

size is guessed from the first image file in the sequence.

@end table

@subsection Examples

@itemize

@item

Use @command{ffmpeg} for creating a video from the images in the file

sequence @file{img-001.jpeg}, @file{img-002.jpeg}, ..., assuming an

input frame rate of 10 frames per second:

@example

ffmpeg -framerate 10 -i 'img-%03d.jpeg' out.mkv

@end example

@item

As above, but start by reading from a file with index 100 in the sequence:

@example

ffmpeg -framerate 10 -start_number 100 -i 'img-%03d.jpeg' out.mkv

@end example

@item

Read images matching the "*.png" glob pattern , that is all the files

terminating with the ".png" suffix:

@example

ffmpeg -framerate 10 -pattern_type glob -i "*.png" out.mkv

@end example

@end itemize

@section mpegts

MPEG-2 transport stream demuxer.

@table @option

@item fix_teletext_pts

Overrides teletext packet PTS and DTS values with the timestamps calculated

from the PCR of the first program which the teletext stream is part of and is

not discarded. Default value is 1, set this option to 0 if you want your

teletext packet PTS and DTS values untouched.

@end table

@section rawvideo

Raw video demuxer.

This demuxer allows to read raw video data. Since there is no header

specifying the assumed video parameters, the user must specify them

in order to be able to decode the data correctly.

This demuxer accepts the following options:

@table @option

@item framerate

Set input video frame rate. Default value is 25.

@item pixel_format

Set the input video pixel format. Default value is @code{yuv420p}.

@item video_size

Set the input video size. This value must be specified explicitly.

@end table

For example to read a rawvideo file @file{input.raw} with

@command{ffplay}, assuming a pixel format of @code{rgb24}, a video

size of @code{320x240}, and a frame rate of 10 images per second, use

the command:

@example

ffplay -f rawvideo -pixel_format rgb24 -video_size 320x240 -framerate 10 input.raw

@end example

@section sbg

SBaGen script demuxer.

This demuxer reads the script language used by SBaGen

@url{http://uazu.net/sbagen/} to generate binaural beats sessions. A SBG

script looks like that:

@example

-SE

a: 300-2.5/3 440+4.5/0

b: 300-2.5/0 440+4.5/3

off: -

NOW      == a

+0:07:00 == b

+0:14:00 == a

+0:21:00 == b

+0:30:00    off

@end example

A SBG script can mix absolute and relative timestamps. If the script uses

either only absolute timestamps (including the script start time) or only

relative ones, then its layout is fixed, and the conversion is

straightforward. On the other hand, if the script mixes both kind of

timestamps, then the @var{NOW} reference for relative timestamps will be

taken from the current time of day at the time the script is read, and the

script layout will be frozen according to that reference. That means that if

the script is directly played, the actual times will match the absolute

timestamps up to the sound controller's clock accuracy, but if the user

somehow pauses the playback or seeks, all times will be shifted accordingly.

@section tedcaptions

JSON captions used for @url{http://www.ted.com/, TED Talks}.

TED does not provide links to the captions, but they can be guessed from the

page. The file @file{tools/bookmarklets.html} from the FFmpeg source tree

contains a bookmarklet to expose them.

This demuxer accepts the following option:

@table @option

@item start_time

Set the start time of the TED talk, in milliseconds. The default is 15000

(15s). It is used to sync the captions with the downloadable videos, because

they include a 15s intro.

@end table

Example: convert the captions to a format most players understand:

@example

ffmpeg -i http://www.ted.com/talks/subtitles/id/1/lang/en talk1-en.srt

@end example

@c man end DEMUXERS