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@chapter Demuxers |
@c man begin DEMUXERS |
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Demuxers are configured elements in FFmpeg that can read the |
multimedia streams from a particular type of file. |
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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}. |
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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}}. |
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The option @code{-formats} of the ff* tools will display the list of |
enabled demuxers. |
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The description of some of the currently available demuxers follows. |
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@section applehttp |
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Apple HTTP Live Streaming demuxer. |
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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". |
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@section asf |
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Advanced Systems Format demuxer. |
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This demuxer is used to demux ASF files and MMS network streams. |
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@table @option |
@item -no_resync_search @var{bool} |
Do not try to resynchronize by looking for a certain optional start code. |
@end table |
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@anchor{concat} |
@section concat |
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Virtual concatenation script demuxer. |
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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. |
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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. |
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All files must have the same streams (same codecs, same time base, etc.). |
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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. |
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@subsection Syntax |
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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: |
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@table @option |
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@item @code{file @var{path}} |
Path to a file to read; special characters and spaces must be escaped with |
backslash or single quotes. |
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All subsequent directives apply to that file. |
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@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. |
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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. |
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@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. |
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If the duration is set for all files, then it is possible to seek in the |
whole concatenated video. |
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@end table |
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@subsection Options |
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This demuxer accepts the following option: |
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@table @option |
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@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. |
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If set to 0, any file name is accepted. |
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The default is -1, it is equivalent to 1 if the format was automatically |
probed and 0 otherwise. |
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@end table |
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@section flv |
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Adobe Flash Video Format demuxer. |
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This demuxer is used to demux FLV files and RTMP network streams. |
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@table @option |
@item -flv_metadata @var{bool} |
Allocate the streams according to the onMetaData array content. |
@end table |
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@section libgme |
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The Game Music Emu library is a collection of video game music file emulators. |
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See @url{http://code.google.com/p/game-music-emu/} for more information. |
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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. |
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For very large files, the @option{max_size} option may have to be adjusted. |
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@section libquvi |
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Play media from Internet services using the quvi project. |
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The demuxer accepts a @option{format} option to request a specific quality. It |
is by default set to @var{best}. |
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See @url{http://quvi.sourceforge.net/} for more information. |
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FFmpeg needs to be built with @code{--enable-libquvi} for this demuxer to be |
enabled. |
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@section image2 |
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Image file demuxer. |
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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}. |
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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. |
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The size, the pixel format, and the format of each image must be the |
same for all the files in the sequence. |
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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. |
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@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. |
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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 "%%". |
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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. |
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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. |
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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: |
@example |
ffmpeg -i img.jpeg img.png |
@end example |
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@item glob |
Select a glob wildcard pattern type. |
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The pattern is interpreted like a @code{glob()} pattern. This is only |
selectable if libavformat was compiled with globbing support. |
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@item glob_sequence @emph{(deprecated, will be removed)} |
Select a mixed glob wildcard/sequence pattern. |
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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. |
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All glob special characters @code{%*?[]@{@}} must be prefixed |
with "%". To escape a literal "%" you shall use "%%". |
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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". |
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This pattern type is deprecated in favor of @var{glob} and |
@var{sequence}. |
@end table |
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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 |
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@subsection Examples |
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@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 |
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@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 |
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@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 |
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@section mpegts |
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MPEG-2 transport stream demuxer. |
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@table @option |
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@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 |
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@section rawvideo |
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Raw video demuxer. |
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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. |
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This demuxer accepts the following options: |
@table @option |
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@item framerate |
Set input video frame rate. Default value is 25. |
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@item pixel_format |
Set the input video pixel format. Default value is @code{yuv420p}. |
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@item video_size |
Set the input video size. This value must be specified explicitly. |
@end table |
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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 |
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@section sbg |
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SBaGen script demuxer. |
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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 |
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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. |
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@section tedcaptions |
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JSON captions used for @url{http://www.ted.com/, TED Talks}. |
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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. |
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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 |
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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 |
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@c man end DEMUXERS |