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 --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=DEMUXER, or disable it with the option --disable-demuxer=DEMUXER.

The option -demuxers of the ff* tools will display the list of enabled demuxers. Use -formats to view a combined list of enabled demuxers and muxers.

The description of some of the currently available demuxers follows.

aa
==

Audible Format 2, 3, and 4 demuxer.

This demuxer is used to demux Audible Format 2, 3, and 4 (.aa) files.

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".

apng
====

Animated Portable Network Graphics demuxer.

This demuxer is used to demux APNG files. All headers, but the PNG signature, up to (but not including) the first fcTL chunk are transmitted as extradata. Frames are then split as being all the chunks between two fcTL ones, or between the last fcTL and IEND chunks.

-ignore_loop BOOL
     Ignore the loop variable in the file if set.

-max_fps INT
     Maximum framerate in frames per second (0 for no limit).

-default_fps INT
     Default framerate in frames per second when none is specified in the file (0 meaning as fast as possible).

asf
===

Advanced Systems Format demuxer.

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

-no_resync_search BOOL
     Do not try to resynchronize by looking for a certain optional start code.

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 packets 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 duration directive can be used to override the duration stored in each file.

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:

file PATH
     Path to a file to read; special characters and spaces must be escaped with backslash or single quotes.

     All subsequent file-related directives apply to that file.

ffconcat version 1.0
     Identify the script type and version. It also sets the safe option to 1 if it was -1.

     To make FFmpeg recognize the format automatically, this directive must appear exactly as is (no extra space or byte-order-mark) on the very first line of the script.

duration 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.

inpoint TIMESTAMP
     In point of the file. When the demuxer opens the file it instantly seeks to the specified timestamp. Seeking is done so that all streams can be presented successfully at In point.

     This directive works best with intra frame codecs, because for non-intra frame ones you will usually get extra packets before the actual In point and the decoded content will most likely contain frames before In point too.

     For each file, packets before the file In point will have timestamps less than the calculated start timestamp of the file (negative in case of the first file), and the duration of the files (if not specified by the duration directive) will be reduced based on their specified In point.

     Because of potential packets before the specified In point, packet timestamps may overlap between two concatenated files.

outpoint TIMESTAMP
     Out point of the file. When the demuxer reaches the specified decoding timestamp in any of the streams, it handles it as an end of file condition and skips the current and all the remaining packets from all streams.

     Out point is exclusive, which means that the demuxer will not output packets with a decoding timestamp greater or equal to Out point.

     This directive works best with intra frame codecs and formats where all streams are tightly interleaved. For non-intra frame codecs you will usually get additional packets with presentation timestamp after Out point therefore the decoded content will most likely contain frames after Out point too. If your streams are not tightly interleaved you may not get all the packets from all streams before Out point and you may only will be able to decode the earliest stream until Out point.

     The duration of the files (if not specified by the duration directive) will be reduced based on their specified Out point.

file_packet_metadata KEY=VALUE
     Metadata of the packets of the file. The specified metadata will be set for each file packet. You can specify this directive multiple times to add multiple metadata entries.

stream
     Introduce a stream in the virtual file. All subsequent stream-related directives apply to the last introduced stream. Some streams properties must be set in order to allow identifying the matching streams in the subfiles. If no streams are defined in the script, the streams from the first file are copied.

exact_stream_id ID
     Set the id of the stream. If this directive is given, the string with the corresponding id in the subfiles will be used. This is especially useful for MPEG-PS (VOB) files, where the order of the streams is not reliable.

Options
-------

This demuxer accepts the following option:

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.

     -1 is equivalent to 1 if the format was automatically probed and 0 otherwise.

auto_convert
     If set to 1, try to perform automatic conversions on packet data to make the streams concatenable. The default is 1.

     Currently, the only conversion is adding the h264_mp4toannexb bitstream filter to H.264 streams in MP4 format. This is necessary in particular if there are resolution changes.

segment_time_metadata
     If set to 1, every packet will contain the LAVF.CONCAT.START_TIME and the LAVF.CONCAT.DURATION packet metadata values which are the start_time and the duration of the respective file segments in the concatenated output expressed in microseconds. The duration metadata is only set if it is known based on the concat file. The default is 0.

Examples
--------

  * Use absolute filenames and include some comments:

          # my first filename
          file /mnt/share/file-1.wav
          # my second filename including whitespace
          file '/mnt/share/file 2.wav'
          # my third filename including whitespace plus single quote
          file '/mnt/share/file 3'\''.wav'

  * Allow for input format auto-probing, use safe filenames and set the duration of the first file:

          ffconcat version 1.0

          file file-1.wav
          duration 20.0

          file subdir/file-2.wav

dash
====

Dynamic Adaptive Streaming over HTTP demuxer.

This demuxer presents all AVStreams found in the manifest. By setting the discard flags on AVStreams the caller can decide which streams to actually receive. Each stream mirrors the id and bandwidth properties from the <Representation> as metadata keys named "id" and "variant_bitrate" respectively.

flv, live_flv
=============

Adobe Flash Video Format demuxer.

This demuxer is used to demux FLV files and RTMP network streams. In case of live network streams, if you force format, you may use live_flv option instead of flv to survive timestamp discontinuities.

     ffmpeg -f flv -i myfile.flv ...
     ffmpeg -f live_flv -i rtmp://<any.server>/anything/key ....

-flv_metadata BOOL
     Allocate the streams according to the onMetaData array content.

-flv_ignore_prevtag BOOL
     Ignore the size of previous tag value.

-flv_full_metadata BOOL
     Output all context of the onMetadata.

gif
===

Animated GIF demuxer.

It accepts the following options:

min_delay
     Set the minimum valid delay between frames in hundredths of seconds. Range is 0 to 6000. Default value is 2.

max_gif_delay
     Set the maximum valid delay between frames in hundredth of seconds. Range is 0 to 65535. Default value is 65535 (nearly eleven minutes), the maximum value allowed by the specification.

default_delay
     Set the default delay between frames in hundredths of seconds. Range is 0 to 6000. Default value is 10.

ignore_loop
     GIF files can contain information to loop a certain number of times (or infinitely). If ignore_loop is set to 1, then the loop setting from the input will be ignored and looping will not occur. If set to 0, then looping will occur and will cycle the number of times according to the GIF. Default value is 1.

For example, with the overlay filter, place an infinitely looping GIF over another video:

     ffmpeg -i input.mp4 -ignore_loop 0 -i input.gif -filter_complex overlay=shortest=1 out.mkv

Note that in the above example the shortest option for overlay filter is used to end the output video at the length of the shortest input file, which in this case is input.mp4 as the GIF in this example loops infinitely.

hls
===

HLS demuxer

It accepts the following options:

live_start_index
     segment index to start live streams at (negative values are from the end).

allowed_extensions
     ',' separated list of file extensions that hls is allowed to access.

max_reload
     Maximum number of times a insufficient list is attempted to be reloaded. Default value is 1000.

http_persistent
     Use persistent HTTP connections. Applicable only for HTTP streams. Enabled by default.

http_multiple
     Use multiple HTTP connections for downloading HTTP segments. Enabled by default for HTTP/1.1 servers.

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 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:

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

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

pattern_type
     Select the pattern type used to interpret the provided filename.

     PATTERN_TYPE accepts one of the following values.

     none
          Disable pattern matching, therefore the video will only contain the specified image. You should use this option if you do not want to create sequences from multiple images and your filenames may contain special pattern characters.

     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 "%0Nd", which specifies the position of the characters representing a sequential number in each filename matched by the pattern. If the form "%d0Nd" is used, the string representing the number in each filename is 0-padded and 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 "%0Nd", the first filename of the file list specified by the pattern must contain a number inclusively contained between START_NUMBER and START_NUMBER+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 img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.; the pattern "i%%m%%g-%d.jpg" will match a sequence of filenames of the form i%m%g-1.jpg, i%m%g-2.jpg, ..., i%m%g-10.jpg, etc.

          Note that the pattern must not necessarily contain "%d" or "%0Nd", for example to convert a single image file img.jpeg you can employ the command:

               ffmpeg -i img.jpeg img.png

     glob
          Select a glob wildcard pattern type.

          The pattern is interpreted like a glob() pattern. This is only selectable if libavformat was compiled with globbing support.

     glob_sequence (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 %*?[]{} that is preceded by an unescaped "%", the pattern is interpreted like a glob() pattern, otherwise it is interpreted like a sequence pattern.

          All glob special characters %*?[]{} must be prefixed with "%". To escape a literal "%" you shall use "%%".

          For example the pattern foo-%*.jpeg will match all the filenames prefixed by "foo-" and terminating with ".jpeg", and 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 GLOB and SEQUENCE.

     Default value is GLOB_SEQUENCE.

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.

start_number
     Set the index of the file matched by the image file pattern to start to read from. Default value is 0.

start_number_range
     Set the index interval range to check when looking for the first image file in the sequence, starting from START_NUMBER. Default value is 5.

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. If set to 2, will set frame timestamp to the modification time of the image file in nanosecond precision.

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.

Examples
--------

  * Use ffmpeg for creating a video from the images in the file sequence img-001.jpeg, img-002.jpeg, ..., assuming an input frame rate of 10 frames per second:

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

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

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

  * Read images matching the "*.png" glob pattern , that is all the files terminating with the ".png" suffix:

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

libgme
======

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

See https://bitbucket.org/mpyne/game-music-emu/overview for more information.

It accepts the following options:

track_index
     Set the index of which track to demux. The demuxer can only export one track. Track indexes start at 0. Default is to pick the first track. Number of tracks is exported as TRACKS metadata entry.

sample_rate
     Set the sampling rate of the exported track. Range is 1000 to 999999. Default is 44100.

max_size (bytes)
     The demuxer buffers the entire file into memory. Adjust this value to set the maximum buffer size, which in turn, acts as a ceiling for the size of files that can be read. Default is 50 MiB.

libmodplug
==========

ModPlug based module demuxer

See https://github.com/Konstanty/libmodplug

It will export one 2-channel 16-bit 44.1 kHz audio stream. Optionally, a pal8 16-color video stream can be exported with or without printed metadata.

It accepts the following options:

noise_reduction
     Apply a simple low-pass filter. Can be 1 (on) or 0 (off). Default is 0.

reverb_depth
     Set amount of reverb. Range 0-100. Default is 0.

reverb_delay
     Set delay in ms, clamped to 40-250 ms. Default is 0.

bass_amount
     Apply bass expansion a.k.a. XBass or megabass. Range is 0 (quiet) to 100 (loud). Default is 0.

bass_range
     Set cutoff i.e. upper-bound for bass frequencies. Range is 10-100 Hz. Default is 0.

surround_depth
     Apply a Dolby Pro-Logic surround effect. Range is 0 (quiet) to 100 (heavy). Default is 0.

surround_delay
     Set surround delay in ms, clamped to 5-40 ms. Default is 0.

max_size
     The demuxer buffers the entire file into memory. Adjust this value to set the maximum buffer size, which in turn, acts as a ceiling for the size of files that can be read. Range is 0 to 100 MiB. 0 removes buffer size limit (not recommended). Default is 5 MiB.

video_stream_expr
     String which is evaluated using the eval API to assign colors to the generated video stream. Variables which can be used are x, y, w, h, t, speed, tempo, order, pattern and row.

video_stream
     Generate video stream. Can be 1 (on) or 0 (off). Default is 0.

video_stream_w
     Set video frame width in 'chars' where one char indicates 8 pixels. Range is 20-512. Default is 30.

video_stream_h
     Set video frame height in 'chars' where one char indicates 8 pixels. Range is 20-512. Default is 30.

video_stream_ptxt
     Print metadata on video stream. Includes speed, tempo, order, pattern, row and ts (time in ms). Can be 1 (on) or 0 (off). Default is 1.

libopenmpt
==========

libopenmpt based module demuxer

See https://lib.openmpt.org/libopenmpt/ for more information.

Some files have multiple subsongs (tracks) this can be set with the subsong option.

It accepts the following options:

subsong
     Set the subsong index. This can be either  'all', 'auto', or the index of the subsong. Subsong indexes start at 0. The default is 'auto'.

     The default value is to let libopenmpt choose.

layout
     Set the channel layout. Valid values are 1, 2, and 4 channel layouts. The default value is STEREO.

sample_rate
     Set the sample rate for libopenmpt to output. Range is from 1000 to INT_MAX. The value default is 48000.

mov/mp4/3gp/QuickTime
=====================

QuickTime / MP4 demuxer.

This demuxer accepts the following options:

enable_drefs
     Enable loading of external tracks, disabled by default. Enabling this can theoretically leak information in some use cases.

use_absolute_path
     Allows loading of external tracks via absolute paths, disabled by default. Enabling this poses a security risk. It should only be enabled if the source is known to be non malicious.

mpegts
======

MPEG-2 transport stream demuxer.

This demuxer accepts the following options:

resync_size
     Set size limit for looking up a new synchronization. Default value is 65536.

skip_unknown_pmt
     Skip PMTs for programs not defined in the PAT. Default value is 0.

fix_teletext_pts
     Override 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.

ts_packetsize
     Output option carrying the raw packet size in bytes. Show the detected raw packet size, cannot be set by the user.

scan_all_pmts
     Scan and combine all PMTs. The value is an integer with value from -1 to 1 (-1 means automatic setting, 1 means enabled, 0 means disabled). Default value is -1.

merge_pmt_versions
     Re-use existing streams when a PMT's version is updated and elementary streams move to different PIDs. Default value is 0.

mpjpeg
======

MJPEG encapsulated in multi-part MIME demuxer.

This demuxer allows reading of MJPEG, where each frame is represented as a part of multipart/x-mixed-replace stream.

strict_mime_boundary
     Default implementation applies a relaxed standard to multi-part MIME boundary detection, to prevent regression with numerous existing endpoints not generating a proper MIME MJPEG stream. Turning this option on by setting it to 1 will result in a stricter check of the boundary value.

rawvideo
========

Raw video demuxer.

This demuxer allows one 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:

framerate
     Set input video frame rate. Default value is 25.

pixel_format
     Set the input video pixel format. Default value is yuv420p.

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

For example to read a rawvideo file input.raw with ffplay, assuming a pixel format of rgb24, a video size of 320x240, and a frame rate of 10 images per second, use the command:

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

sbg
===

SBaGen script demuxer.

This demuxer reads the script language used by SBaGen http://uazu.net/sbagen/ to generate binaural beats sessions. A SBG script looks like that:

     -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

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 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.

tedcaptions
===========

JSON captions used for TED Talks (http://www.ted.com/).

TED does not provide links to the captions, but they can be guessed from the page. The file tools/bookmarklets.html from the FFmpeg source tree contains a bookmarklet to expose them.

This demuxer accepts the following option:

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.

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

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

vapoursynth
===========

Vapoursynth wrapper.

Due to security concerns, Vapoursynth scripts will not be autodetected so the input format has to be forced. For ff* CLI tools, add -f vapoursynth before the input -i yourscript.vpy.

This demuxer accepts the following option:

max_script_size
     The demuxer buffers the entire script into memory. Adjust this value to set the maximum buffer size, which in turn, acts as a ceiling for the size of scripts that can be read. Default is 1 MiB.