FFMPEG-FORMATS(1)					     FFMPEG-FORMATS(1)

NAME
       ffmpeg-formats - FFmpeg formats

DESCRIPTION
       This document describes the supported formats (muxers and demuxers)
       provided by the libavformat library.

FORMAT OPTIONS
       The libavformat library provides some generic global options, which can
       be set on all the muxers and demuxers. In addition each muxer or
       demuxer may support so-called private options, which are specific for
       that component.

       Options may be set by specifying -option value in the FFmpeg tools, or
       by setting the value explicitly in the "AVFormatContext" options or
       using the libavutil/opt.h API for programmatic use.

       The list of supported options follows:

       avioflags flags (input/output)
	   Possible values:

	   direct
	       Reduce buffering.

       probesize integer (input)
	   Set probing size in bytes, i.e. the size of the data to analyze to
	   get stream information. A higher value will enable detecting more
	   information in case it is dispersed into the stream, but will
	   increase latency. Must be an integer not lesser than 32. It is
	   5000000 by default.

       packetsize integer (output)
	   Set packet size.

       fflags flags
	   Set format flags. Some are implemented for a limited number of
	   formats.

	   Possible values for input files:

	   discardcorrupt
	       Discard corrupted packets.

	   fastseek
	       Enable fast, but inaccurate seeks for some formats.

	   genpts
	       Generate missing PTS if DTS is present.

	   igndts
	       Ignore DTS if PTS is set. Inert when nofillin is set.

	   ignidx
	       Ignore index.

	   keepside (deprecated,inert)
	   nobuffer
	       Reduce the latency introduced by buffering during initial input
	       streams analysis.

	   nofillin
	       Do not fill in missing values in packet fields that can be
	       exactly calculated.

	   noparse
	       Disable AVParsers, this needs "+nofillin" too.

	   sortdts
	       Try to interleave output packets by DTS. At present, available
	       only for AVIs with an index.

	   Possible values for output files:

	   autobsf
	       Automatically apply bitstream filters as required by the output
	       format. Enabled by default.

	   bitexact
	       Only write platform-, build- and time-independent data.	This
	       ensures that file and data checksums are reproducible and match
	       between platforms. Its primary use is for regression testing.

	   flush_packets
	       Write out packets immediately.

	   latm (deprecated,inert)
	   shortest
	       Stop muxing at the end of the shortest stream.  It may be
	       needed to increase max_interleave_delta to avoid flushing the
	       longer streams before EOF.

       seek2any integer (input)
	   Allow seeking to non-keyframes on demuxer level when supported if
	   set to 1.  Default is 0.

       analyzeduration integer (input)
	   Specify how many microseconds are analyzed to probe the input. A
	   higher value will enable detecting more accurate information, but
	   will increase latency. It defaults to 5,000,000 microseconds = 5
	   seconds.

       cryptokey hexadecimal string (input)
	   Set decryption key.

       indexmem integer (input)
	   Set max memory used for timestamp index (per stream).

       rtbufsize integer (input)
	   Set max memory used for buffering real-time frames.

       fdebug flags (input/output)
	   Print specific debug info.

	   Possible values:

	   ts
       max_delay integer (input/output)
	   Set maximum muxing or demuxing delay in microseconds.

       fpsprobesize integer (input)
	   Set number of frames used to probe fps.

       audio_preload integer (output)
	   Set microseconds by which audio packets should be interleaved
	   earlier.

       chunk_duration integer (output)
	   Set microseconds for each chunk.

       chunk_size integer (output)
	   Set size in bytes for each chunk.

       err_detect, f_err_detect flags (input)
	   Set error detection flags. "f_err_detect" is deprecated and should
	   be used only via the ffmpeg tool.

	   Possible values:

	   crccheck
	       Verify embedded CRCs.

	   bitstream
	       Detect bitstream specification deviations.

	   buffer
	       Detect improper bitstream length.

	   explode
	       Abort decoding on minor error detection.

	   careful
	       Consider things that violate the spec and have not been seen in
	       the wild as errors.

	   compliant
	       Consider all spec non compliancies as errors.

	   aggressive
	       Consider things that a sane encoder should not do as an error.

       max_interleave_delta integer (output)
	   Set maximum buffering duration for interleaving. The duration is
	   expressed in microseconds, and defaults to 1000000 (1 second).

	   To ensure all the streams are interleaved correctly, libavformat
	   will wait until it has at least one packet for each stream before
	   actually writing any packets to the output file. When some streams
	   are "sparse" (i.e. there are large gaps between successive
	   packets), this can result in excessive buffering.

	   This field specifies the maximum difference between the timestamps
	   of the first and the last packet in the muxing queue, above which
	   libavformat will output a packet regardless of whether it has
	   queued a packet for all the streams.

	   If set to 0, libavformat will continue buffering packets until it
	   has a packet for each stream, regardless of the maximum timestamp
	   difference between the buffered packets.

       use_wallclock_as_timestamps integer (input)
	   Use wallclock as timestamps if set to 1. Default is 0.

       avoid_negative_ts integer (output)
	   Possible values:

	   make_non_negative
	       Shift timestamps to make them non-negative.  Also note that
	       this affects only leading negative timestamps, and not non-
	       monotonic negative timestamps.

	   make_zero
	       Shift timestamps so that the first timestamp is 0.

	   auto (default)
	       Enables shifting when required by the target format.

	   disabled
	       Disables shifting of timestamp.

	   When shifting is enabled, all output timestamps are shifted by the
	   same amount. Audio, video, and subtitles desynching and relative
	   timestamp differences are preserved compared to how they would have
	   been without shifting.

       skip_initial_bytes integer (input)
	   Set number of bytes to skip before reading header and frames if set
	   to 1.  Default is 0.

       correct_ts_overflow integer (input)
	   Correct single timestamp overflows if set to 1. Default is 1.

       flush_packets integer (output)
	   Flush the underlying I/O stream after each packet. Default is -1
	   (auto), which means that the underlying protocol will decide, 1
	   enables it, and has the effect of reducing the latency, 0 disables
	   it and may increase IO throughput in some cases.

       output_ts_offset offset (output)
	   Set the output time offset.

	   offset must be a time duration specification, see the Time duration
	   section in the ffmpeg-utils(1) manual.

	   The offset is added by the muxer to the output timestamps.

	   Specifying a positive offset means that the corresponding streams
	   are delayed bt the time duration specified in offset. Default value
	   is 0 (meaning that no offset is applied).

       format_whitelist list (input)
	   "," separated list of allowed demuxers. By default all are allowed.

       dump_separator string (input)
	   Separator used to separate the fields printed on the command line
	   about the Stream parameters.  For example to separate the fields
	   with newlines and indention:

		   ffprobe -dump_separator "
					     "	-i ~/videos/matrixbench_mpeg2.mpg

       max_streams integer (input)
	   Specifies the maximum number of streams. This can be used to reject
	   files that would require too many resources due to a large number
	   of streams.

       skip_estimate_duration_from_pts bool (input)
	   Skip estimation of input duration when calculated using PTS.  At
	   present, applicable for MPEG-PS and MPEG-TS.

   Format stream specifiers
       Format stream specifiers allow selection of one or more streams that
       match specific properties.

       Possible forms of stream specifiers are:

       stream_index
	   Matches the stream with this index.

       stream_type[:stream_index]
	   stream_type is one of following: 'v' for video, 'a' for audio, 's'
	   for subtitle, 'd' for data, and 't' for attachments. If
	   stream_index is given, then it matches the stream number
	   stream_index of this type. Otherwise, it matches all streams of
	   this type.

       p:program_id[:stream_index]
	   If stream_index is given, then it matches the stream with number
	   stream_index in the program with the id program_id. Otherwise, it
	   matches all streams in the program.

       #stream_id
	   Matches the stream by a format-specific ID.

       The exact semantics of stream specifiers is defined by the
       "avformat_match_stream_specifier()" function declared in the
       libavformat/avformat.h header.

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 <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 track_index option can be used to select a different
       track. Track indexes start at 0. The demuxer exports the number of
       tracks as tracks meta data entry.

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

   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 <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

MUXERS
       Muxers are configured elements in FFmpeg which allow writing multimedia
       streams to a particular type of file.

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

       You can disable all the muxers with the configure option
       "--disable-muxers" and selectively enable / disable single muxers with
       the options "--enable-muxer=MUXER" / "--disable-muxer=MUXER".

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

       A description of some of the currently available muxers follows.

   aiff
       Audio Interchange File Format muxer.

       Options

       It accepts the following options:

       write_id3v2
	   Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).

       id3v2_version
	   Select ID3v2 version to write. Currently only version 3 and 4 (aka.
	   ID3v2.3 and ID3v2.4) are supported. The default is version 4.

   asf
       Advanced Systems Format muxer.

       Note that Windows Media Audio (wma) and Windows Media Video (wmv) use
       this muxer too.

       Options

       It accepts the following options:

       packet_size
	   Set the muxer packet size. By tuning this setting you may reduce
	   data fragmentation or muxer overhead depending on your source.
	   Default value is 3200, minimum is 100, maximum is 64k.

   avi
       Audio Video Interleaved muxer.

       Options

       It accepts the following options:

       reserve_index_space
	   Reserve the specified amount of bytes for the OpenDML master index
	   of each stream within the file header. By default additional master
	   indexes are embedded within the data packets if there is no space
	   left in the first master index and are linked together as a chain
	   of indexes. This index structure can cause problems for some use
	   cases, e.g. third-party software strictly relying on the OpenDML
	   index specification or when file seeking is slow. Reserving enough
	   index space in the file header avoids these problems.

	   The required index space depends on the output file size and should
	   be about 16 bytes per gigabyte. When this option is omitted or set
	   to zero the necessary index space is guessed.

       write_channel_mask
	   Write the channel layout mask into the audio stream header.

	   This option is enabled by default. Disabling the channel mask can
	   be useful in specific scenarios, e.g. when merging multiple audio
	   streams into one for compatibility with software that only supports
	   a single audio stream in AVI (see the "amerge" section in the
	   ffmpeg-filters manual).

   chromaprint
       Chromaprint fingerprinter

       This muxer feeds audio data to the Chromaprint library, which generates
       a fingerprint for the provided audio data. It takes a single signed
       native-endian 16-bit raw audio stream.

       Options

       silence_threshold
	   Threshold for detecting silence, ranges from 0 to 32767. -1 for
	   default (required for use with the AcoustID service).

       algorithm
	   Algorithm index to fingerprint with.

       fp_format
	   Format to output the fingerprint as. Accepts the following options:

	   raw Binary raw fingerprint

	   compressed
	       Binary compressed fingerprint

	   base64
	       Base64 compressed fingerprint

   crc
       CRC (Cyclic Redundancy Check) testing format.

       This muxer computes and prints the Adler-32 CRC of all the input audio
       and video frames. By default audio frames are converted to signed
       16-bit raw audio and video frames to raw video before computing the
       CRC.

       The output of the muxer consists of a single line of the form:
       CRC=0xCRC, where CRC is a hexadecimal number 0-padded to 8 digits
       containing the CRC for all the decoded input frames.

       See also the framecrc muxer.

       Examples

       For example to compute the CRC of the input, and store it in the file
       out.crc:

	       ffmpeg -i INPUT -f crc out.crc

       You can print the CRC to stdout with the command:

	       ffmpeg -i INPUT -f crc -

       You can select the output format of each frame with ffmpeg by
       specifying the audio and video codec and format. For example to compute
       the CRC of the input audio converted to PCM unsigned 8-bit and the
       input video converted to MPEG-2 video, use the command:

	       ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -

   flv
       Adobe Flash Video Format muxer.

       This muxer accepts the following options:

       flvflags flags
	   Possible values:

	   aac_seq_header_detect
	       Place AAC sequence header based on audio stream data.

	   no_sequence_end
	       Disable sequence end tag.

	   no_metadata
	       Disable metadata tag.

	   no_duration_filesize
	       Disable duration and filesize in metadata when they are equal
	       to zero at the end of stream. (Be used to non-seekable living
	       stream).

	   add_keyframe_index
	       Used to facilitate seeking; particularly for HTTP pseudo
	       streaming.

   dash
       Dynamic Adaptive Streaming over HTTP (DASH) muxer that creates segments
       and manifest files according to the MPEG-DASH standard ISO/IEC
       23009-1:2014.

       For more information see:

       ·   ISO DASH Specification:
	   <http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip>

       ·   WebM DASH Specification:
	   <https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification>

       It creates a MPD manifest file and segment files for each stream.

       The segment filename might contain pre-defined identifiers used with
       SegmentTemplate as defined in section 5.3.9.4.4 of the standard.
       Available identifiers are "$RepresentationID$", "$Number$",
       "$Bandwidth$" and "$Time$".

	       ffmpeg -re -i <input> -map 0 -map 0 -c:a libfdk_aac -c:v libx264
	       -b:v:0 800k -b:v:1 300k -s:v:1 320x170 -profile:v:1 baseline
	       -profile:v:0 main -bf 1 -keyint_min 120 -g 120 -sc_threshold 0
	       -b_strategy 0 -ar:a:1 22050 -use_timeline 1 -use_template 1
	       -window_size 5 -adaptation_sets "id=0,streams=v id=1,streams=a"
	       -f dash /path/to/out.mpd

       -min_seg_duration microseconds
	   This is a deprecated option to set the segment length in
	   microseconds, use seg_duration instead.

       -seg_duration duration
	   Set the segment length in seconds (fractional value can be set).
	   The value is treated as average segment duration when use_template
	   is enabled and use_timeline is disabled and as minimum segment
	   duration for all the other use cases.

       -window_size size
	   Set the maximum number of segments kept in the manifest.

       -extra_window_size size
	   Set the maximum number of segments kept outside of the manifest
	   before removing from disk.

       -remove_at_exit remove
	   Enable (1) or disable (0) removal of all segments when finished.

       -use_template template
	   Enable (1) or disable (0) use of SegmentTemplate instead of
	   SegmentList.

       -use_timeline timeline
	   Enable (1) or disable (0) use of SegmentTimeline in
	   SegmentTemplate.

       -single_file single_file
	   Enable (1) or disable (0) storing all segments in one file,
	   accessed using byte ranges.

       -single_file_name file_name
	   DASH-templated name to be used for baseURL. Implies single_file set
	   to "1".

       -init_seg_name init_name
	   DASH-templated name to used for the initialization segment. Default
	   is "init-stream$RepresentationID$.m4s"

       -media_seg_name segment_name
	   DASH-templated name to used for the media segments. Default is
	   "chunk-stream$RepresentationID$-$Number%05d$.m4s"

       -utc_timing_url utc_url
	   URL of the page that will return the UTC timestamp in ISO format.
	   Example: "https://time.akamai.com/?iso"

       method method
	   Use the given HTTP method to create output files. Generally set to
	   PUT or POST.

       -http_user_agent user_agent
	   Override User-Agent field in HTTP header. Applicable only for HTTP
	   output.

       -http_persistent http_persistent
	   Use persistent HTTP connections. Applicable only for HTTP output.

       -hls_playlist hls_playlist
	   Generate HLS playlist files as well. The master playlist is
	   generated with the filename master.m3u8.  One media playlist file
	   is generated for each stream with filenames media_0.m3u8,
	   media_1.m3u8, etc.

       -streaming streaming
	   Enable (1) or disable (0) chunk streaming mode of output. In chunk
	   streaming mode, each frame will be a moof fragment which forms a
	   chunk.

       -adaptation_sets adaptation_sets
	   Assign streams to AdaptationSets. Syntax is "id=x,streams=a,b,c
	   id=y,streams=d,e" with x and y being the IDs of the adaptation sets
	   and a,b,c,d and e are the indices of the mapped streams.

	   To map all video (or audio) streams to an AdaptationSet, "v" (or
	   "a") can be used as stream identifier instead of IDs.

	   When no assignment is defined, this defaults to an AdaptationSet
	   for each stream.

       -timeout timeout
	   Set timeout for socket I/O operations. Applicable only for HTTP
	   output.

       -index_correction index_correction
	   Enable (1) or Disable (0) segment index correction logic.
	   Applicable only when use_template is enabled and use_timeline is
	   disabled.

	   When enabled, the logic monitors the flow of segment indexes. If a
	   streams's segment index value is not at the expected real time
	   position, then the logic corrects that index value.

	   Typically this logic is needed in live streaming use cases. The
	   network bandwidth fluctuations are common during long run
	   streaming. Each fluctuation can cause the segment indexes fall
	   behind the expected real time position.

       -format_options options_list
	   Set container format (mp4/webm) options using a ":" separated list
	   of key=value parameters. Values containing ":" special characters
	   must be escaped.

       dash_segment_type dash_segment_type
	   Possible values:

       mp4 If this flag is set, the dash segment files will be in in ISOBMFF
	   format. This is the default format.

       webm
	   If this flag is set, the dash segment files will be in in WebM
	   format.

   framecrc
       Per-packet CRC (Cyclic Redundancy Check) testing format.

       This muxer computes and prints the Adler-32 CRC for each audio and
       video packet. By default audio frames are converted to signed 16-bit
       raw audio and video frames to raw video before computing the CRC.

       The output of the muxer consists of a line for each audio and video
       packet of the form:

	       <stream_index>, <packet_dts>, <packet_pts>, <packet_duration>, <packet_size>, 0x<CRC>

       CRC is a hexadecimal number 0-padded to 8 digits containing the CRC of
       the packet.

       Examples

       For example to compute the CRC of the audio and video frames in INPUT,
       converted to raw audio and video packets, and store it in the file
       out.crc:

	       ffmpeg -i INPUT -f framecrc out.crc

       To print the information to stdout, use the command:

	       ffmpeg -i INPUT -f framecrc -

       With ffmpeg, you can select the output format to which the audio and
       video frames are encoded before computing the CRC for each packet by
       specifying the audio and video codec. For example, to compute the CRC
       of each decoded input audio frame converted to PCM unsigned 8-bit and
       of each decoded input video frame converted to MPEG-2 video, use the
       command:

	       ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -

       See also the crc muxer.

   framehash
       Per-packet hash testing format.

       This muxer computes and prints a cryptographic hash for each audio and
       video packet. This can be used for packet-by-packet equality checks
       without having to individually do a binary comparison on each.

       By default audio frames are converted to signed 16-bit raw audio and
       video frames to raw video before computing the hash, but the output of
       explicit conversions to other codecs can also be used. It uses the
       SHA-256 cryptographic hash function by default, but supports several
       other algorithms.

       The output of the muxer consists of a line for each audio and video
       packet of the form:

	       <stream_index>, <packet_dts>, <packet_pts>, <packet_duration>, <packet_size>, <hash>

       hash is a hexadecimal number representing the computed hash for the
       packet.

       hash algorithm
	   Use the cryptographic hash function specified by the string
	   algorithm.  Supported values include "MD5", "murmur3", "RIPEMD128",
	   "RIPEMD160", "RIPEMD256", "RIPEMD320", "SHA160", "SHA224", "SHA256"
	   (default), "SHA512/224", "SHA512/256", "SHA384", "SHA512", "CRC32"
	   and "adler32".

       Examples

       To compute the SHA-256 hash of the audio and video frames in INPUT,
       converted to raw audio and video packets, and store it in the file
       out.sha256:

	       ffmpeg -i INPUT -f framehash out.sha256

       To print the information to stdout, using the MD5 hash function, use
       the command:

	       ffmpeg -i INPUT -f framehash -hash md5 -

       See also the hash muxer.

   framemd5
       Per-packet MD5 testing format.

       This is a variant of the framehash muxer. Unlike that muxer, it
       defaults to using the MD5 hash function.

       Examples

       To compute the MD5 hash of the audio and video frames in INPUT,
       converted to raw audio and video packets, and store it in the file
       out.md5:

	       ffmpeg -i INPUT -f framemd5 out.md5

       To print the information to stdout, use the command:

	       ffmpeg -i INPUT -f framemd5 -

       See also the framehash and md5 muxers.

   gif
       Animated GIF muxer.

       It accepts the following options:

       loop
	   Set the number of times to loop the output. Use "-1" for no loop, 0
	   for looping indefinitely (default).

       final_delay
	   Force the delay (expressed in centiseconds) after the last frame.
	   Each frame ends with a delay until the next frame. The default is
	   "-1", which is a special value to tell the muxer to re-use the
	   previous delay. In case of a loop, you might want to customize this
	   value to mark a pause for instance.

       For example, to encode a gif looping 10 times, with a 5 seconds delay
       between the loops:

	       ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif

       Note 1: if you wish to extract the frames into separate GIF files, you
       need to force the image2 muxer:

	       ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"

       Note 2: the GIF format has a very large time base: the delay between
       two frames can therefore not be smaller than one centi second.

   hash
       Hash testing format.

       This muxer computes and prints a cryptographic hash of all the input
       audio and video frames. This can be used for equality checks without
       having to do a complete binary comparison.

       By default audio frames are converted to signed 16-bit raw audio and
       video frames to raw video before computing the hash, but the output of
       explicit conversions to other codecs can also be used. Timestamps are
       ignored. It uses the SHA-256 cryptographic hash function by default,
       but supports several other algorithms.

       The output of the muxer consists of a single line of the form:
       algo=hash, where algo is a short string representing the hash function
       used, and hash is a hexadecimal number representing the computed hash.

       hash algorithm
	   Use the cryptographic hash function specified by the string
	   algorithm.  Supported values include "MD5", "murmur3", "RIPEMD128",
	   "RIPEMD160", "RIPEMD256", "RIPEMD320", "SHA160", "SHA224", "SHA256"
	   (default), "SHA512/224", "SHA512/256", "SHA384", "SHA512", "CRC32"
	   and "adler32".

       Examples

       To compute the SHA-256 hash of the input converted to raw audio and
       video, and store it in the file out.sha256:

	       ffmpeg -i INPUT -f hash out.sha256

       To print an MD5 hash to stdout use the command:

	       ffmpeg -i INPUT -f hash -hash md5 -

       See also the framehash muxer.

   hls
       Apple HTTP Live Streaming muxer that segments MPEG-TS according to the
       HTTP Live Streaming (HLS) specification.

       It creates a playlist file, and one or more segment files. The output
       filename specifies the playlist filename.

       By default, the muxer creates a file for each segment produced. These
       files have the same name as the playlist, followed by a sequential
       number and a .ts extension.

       Make sure to require a closed GOP when encoding and to set the GOP size
       to fit your segment time constraint.

       For example, to convert an input file with ffmpeg:

	       ffmpeg -i in.mkv -c:v h264 -flags +cgop -g 30 -hls_time 1 out.m3u8

       This example will produce the playlist, out.m3u8, and segment files:
       out0.ts, out1.ts, out2.ts, etc.

       See also the segment muxer, which provides a more generic and flexible
       implementation of a segmenter, and can be used to perform HLS
       segmentation.

       Options

       This muxer supports the following options:

       hls_init_time seconds
	   Set the initial target segment length in seconds. Default value is
	   0.  Segment will be cut on the next key frame after this time has
	   passed on the first m3u8 list.  After the initial playlist is
	   filled ffmpeg will cut segments at duration equal to "hls_time"

       hls_time seconds
	   Set the target segment length in seconds. Default value is 2.
	   Segment will be cut on the next key frame after this time has
	   passed.

       hls_list_size size
	   Set the maximum number of playlist entries. If set to 0 the list
	   file will contain all the segments. Default value is 5.

       hls_delete_threshold size
	   Set the number of unreferenced segments to keep on disk before
	   "hls_flags delete_segments" deletes them. Increase this to allow
	   continue clients to download segments which were recently
	   referenced in the playlist. Default value is 1, meaning segments
	   older than "hls_list_size+1" will be deleted.

       hls_ts_options options_list
	   Set output format options using a :-separated list of key=value
	   parameters. Values containing ":" special characters must be
	   escaped.

       hls_wrap wrap
	   This is a deprecated option, you can use "hls_list_size" and
	   "hls_flags delete_segments" instead it

	   This option is useful to avoid to fill the disk with many segment
	   files, and limits the maximum number of segment files written to
	   disk to wrap.

       hls_start_number_source
	   Start the playlist sequence number ("#EXT-X-MEDIA-SEQUENCE")
	   according to the specified source.  Unless "hls_flags single_file"
	   is set, it also specifies source of starting sequence numbers of
	   segment and subtitle filenames. In any case, if "hls_flags
	   append_list" is set and read playlist sequence number is greater
	   than the specified start sequence number, then that value will be
	   used as start value.

	   It accepts the following values:

	   generic (default)
	       Set the starting sequence numbers according to start_number
	       option value.

	   epoch
	       The start number will be the seconds since epoch (1970-01-01
	       00:00:00)

	   datetime
	       The start number will be based on the current date/time as
	       YYYYmmddHHMMSS. e.g. 20161231235759.

       start_number number
	   Start the playlist sequence number ("#EXT-X-MEDIA-SEQUENCE") from
	   the specified number when hls_start_number_source value is generic.
	   (This is the default case.)	Unless "hls_flags single_file" is set,
	   it also specifies starting sequence numbers of segment and subtitle
	   filenames.  Default value is 0.

       hls_allow_cache allowcache
	   Explicitly set whether the client MAY \fIs0(1) or MUST NOT \fIs0(0)
	   cache media segments.

       hls_base_url baseurl
	   Append baseurl to every entry in the playlist.  Useful to generate
	   playlists with absolute paths.

	   Note that the playlist sequence number must be unique for each
	   segment and it is not to be confused with the segment filename
	   sequence number which can be cyclic, for example if the wrap option
	   is specified.

       hls_segment_filename filename
	   Set the segment filename. Unless "hls_flags single_file" is set,
	   filename is used as a string format with the segment number:

		   ffmpeg -i in.nut -hls_segment_filename 'file%03d.ts' out.m3u8

	   This example will produce the playlist, out.m3u8, and segment
	   files: file000.ts, file001.ts, file002.ts, etc.

	   filename may contain full path or relative path specification, but
	   only the file name part without any path info will be contained in
	   the m3u8 segment list.  Should a relative path be specified, the
	   path of the created segment files will be relative to the current
	   working directory.  When use_localtime_mkdir is set, the whole
	   expanded value of filename will be written into the m3u8 segment
	   list.

	   When "var_stream_map" is set with two or more variant streams, the
	   filename pattern must contain the string "%v", this string
	   specifies the position of variant stream index in the generated
	   segment file names.

		   ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
		     -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
		     -hls_segment_filename 'file_%v_%03d.ts' out_%v.m3u8

	   This example will produce the playlists segment file sets:
	   file_0_000.ts, file_0_001.ts, file_0_002.ts, etc. and
	   file_1_000.ts, file_1_001.ts, file_1_002.ts, etc.

	   The string "%v" may be present in the filename or in the last
	   directory name containing the file. If the string is present in the
	   directory name, then sub-directories are created after expanding
	   the directory name pattern. This enables creation of segments
	   corresponding to different variant streams in subdirectories.

		   ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
		     -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
		     -hls_segment_filename 'vs%v/file_%03d.ts' vs%v/out.m3u8

	   This example will produce the playlists segment file sets:
	   vs0/file_000.ts, vs0/file_001.ts, vs0/file_002.ts, etc. and
	   vs1/file_000.ts, vs1/file_001.ts, vs1/file_002.ts, etc.

       use_localtime
	   Use strftime() on filename to expand the segment filename with
	   localtime.  The segment number is also available in this mode, but
	   to use it, you need to specify second_level_segment_index hls_flag
	   and %%d will be the specifier.

		   ffmpeg -i in.nut -use_localtime 1 -hls_segment_filename 'file-%Y%m%d-%s.ts' out.m3u8

	   This example will produce the playlist, out.m3u8, and segment
	   files: file-20160215-1455569023.ts, file-20160215-1455569024.ts,
	   etc.  Note: On some systems/environments, the %s specifier is not
	   available. See
	     "strftime()" documentation.

		   ffmpeg -i in.nut -use_localtime 1 -hls_flags second_level_segment_index -hls_segment_filename 'file-%Y%m%d-%%04d.ts' out.m3u8

	   This example will produce the playlist, out.m3u8, and segment
	   files: file-20160215-0001.ts, file-20160215-0002.ts, etc.

       use_localtime_mkdir
	   Used together with -use_localtime, it will create all
	   subdirectories which is expanded in filename.

		   ffmpeg -i in.nut -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename '%Y%m%d/file-%Y%m%d-%s.ts' out.m3u8

	   This example will create a directory 201560215 (if it does not
	   exist), and then produce the playlist, out.m3u8, and segment files:
	   20160215/file-20160215-1455569023.ts,
	   20160215/file-20160215-1455569024.ts, etc.

		   ffmpeg -i in.nut -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename '%Y/%m/%d/file-%Y%m%d-%s.ts' out.m3u8

	   This example will create a directory hierarchy 2016/02/15 (if any
	   of them do not exist), and then produce the playlist, out.m3u8, and
	   segment files: 2016/02/15/file-20160215-1455569023.ts,
	   2016/02/15/file-20160215-1455569024.ts, etc.

       hls_key_info_file key_info_file
	   Use the information in key_info_file for segment encryption. The
	   first line of key_info_file specifies the key URI written to the
	   playlist. The key URL is used to access the encryption key during
	   playback. The second line specifies the path to the key file used
	   to obtain the key during the encryption process. The key file is
	   read as a single packed array of 16 octets in binary format. The
	   optional third line specifies the initialization vector (IV) as a
	   hexadecimal string to be used instead of the segment sequence
	   number (default) for encryption. Changes to key_info_file will
	   result in segment encryption with the new key/IV and an entry in
	   the playlist for the new key URI/IV if "hls_flags periodic_rekey"
	   is enabled.

	   Key info file format:

		   <key URI>
		   <key file path>
		   <IV> (optional)

	   Example key URIs:

		   http://server/file.key
		   /path/to/file.key
		   file.key

	   Example key file paths:

		   file.key
		   /path/to/file.key

	   Example IV:

		   0123456789ABCDEF0123456789ABCDEF

	   Key info file example:

		   http://server/file.key
		   /path/to/file.key
		   0123456789ABCDEF0123456789ABCDEF

	   Example shell script:

		   #!/bin/sh
		   BASE_URL=${1:-'.'}
		   openssl rand 16 > file.key
		   echo $BASE_URL/file.key > file.keyinfo
		   echo file.key >> file.keyinfo
		   echo $(openssl rand -hex 16) >> file.keyinfo
		   ffmpeg -f lavfi -re -i testsrc -c:v h264 -hls_flags delete_segments \
		     -hls_key_info_file file.keyinfo out.m3u8

       -hls_enc enc
	   Enable (1) or disable (0) the AES128 encryption.  When enabled
	   every segment generated is encrypted and the encryption key is
	   saved as playlist name.key.

       -hls_enc_key key
	   Hex-coded 16byte key to encrypt the segments, by default it is
	   randomly generated.

       -hls_enc_key_url keyurl
	   If set, keyurl is prepended instead of baseurl to the key filename
	   in the playlist.

       -hls_enc_iv iv
	   Hex-coded 16byte initialization vector for every segment instead of
	   the autogenerated ones.

       hls_segment_type flags
	   Possible values:

	   mpegts
	       If this flag is set, the hls segment files will format to
	       mpegts.	the mpegts files is used in all hls versions.

	   fmp4
	       If this flag is set, the hls segment files will format to
	       fragment mp4 looks like dash.  the fmp4 files is used in hls
	       after version 7.

       hls_fmp4_init_filename filename
	   set filename to the fragment files header file, default filename is
	   init.mp4.

	   When "var_stream_map" is set with two or more variant streams, the
	   filename pattern must contain the string "%v", this string
	   specifies the position of variant stream index in the generated
	   init file names.  The string "%v" may be present in the filename or
	   in the last directory name containing the file. If the string is
	   present in the directory name, then sub-directories are created
	   after expanding the directory name pattern. This enables creation
	   of init files corresponding to different variant streams in
	   subdirectories.

       hls_flags flags
	   Possible values:

	   single_file
	       If this flag is set, the muxer will store all segments in a
	       single MPEG-TS file, and will use byte ranges in the playlist.
	       HLS playlists generated with this way will have the version
	       number 4.  For example:

		       ffmpeg -i in.nut -hls_flags single_file out.m3u8

	       Will produce the playlist, out.m3u8, and a single segment file,
	       out.ts.

	   delete_segments
	       Segment files removed from the playlist are deleted after a
	       period of time equal to the duration of the segment plus the
	       duration of the playlist.

	   append_list
	       Append new segments into the end of old segment list, and
	       remove the "#EXT-X-ENDLIST" from the old segment list.

	   round_durations
	       Round the duration info in the playlist file segment info to
	       integer values, instead of using floating point.

	   discont_start
	       Add the "#EXT-X-DISCONTINUITY" tag to the playlist, before the
	       first segment's information.

	   omit_endlist
	       Do not append the "EXT-X-ENDLIST" tag at the end of the
	       playlist.

	   periodic_rekey
	       The file specified by "hls_key_info_file" will be checked
	       periodically and detect updates to the encryption info. Be sure
	       to replace this file atomically, including the file containing
	       the AES encryption key.

	   independent_segments
	       Add the "#EXT-X-INDEPENDENT-SEGMENTS" to playlists that has
	       video segments and when all the segments of that playlist are
	       guaranteed to start with a Key frame.

	   split_by_time
	       Allow segments to start on frames other than keyframes. This
	       improves behavior on some players when the time between
	       keyframes is inconsistent, but may make things worse on others,
	       and can cause some oddities during seeking. This flag should be
	       used with the "hls_time" option.

	   program_date_time
	       Generate "EXT-X-PROGRAM-DATE-TIME" tags.

	   second_level_segment_index
	       Makes it possible to use segment indexes as %%d in
	       hls_segment_filename expression besides date/time values when
	       use_localtime is on.  To get fixed width numbers with trailing
	       zeroes, %%0xd format is available where x is the required
	       width.

	   second_level_segment_size
	       Makes it possible to use segment sizes (counted in bytes) as
	       %%s in hls_segment_filename expression besides date/time values
	       when use_localtime is on.  To get fixed width numbers with
	       trailing zeroes, %%0xs format is available where x is the
	       required width.

	   second_level_segment_duration
	       Makes it possible to use segment duration (calculated  in
	       microseconds) as %%t in hls_segment_filename expression besides
	       date/time values when use_localtime is on.  To get fixed width
	       numbers with trailing zeroes, %%0xt format is available where x
	       is the required width.

		       ffmpeg -i sample.mpeg \
			  -f hls -hls_time 3 -hls_list_size 5 \
			  -hls_flags second_level_segment_index+second_level_segment_size+second_level_segment_duration \
			  -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename "segment_%Y%m%d%H%M%S_%%04d_%%08s_%%013t.ts" stream.m3u8

	       This will produce segments like this:
	       segment_20170102194334_0003_00122200_0000003000000.ts,
	       segment_20170102194334_0004_00120072_0000003000000.ts etc.

	   temp_file
	       Write segment data to filename.tmp and rename to filename only
	       once the segment is complete. A webserver serving up segments
	       can be configured to reject requests to *.tmp to prevent access
	       to in-progress segments before they have been added to the m3u8
	       playlist.

       hls_playlist_type event
	   Emit "#EXT-X-PLAYLIST-TYPE:EVENT" in the m3u8 header. Forces
	   hls_list_size to 0; the playlist can only be appended to.

       hls_playlist_type vod
	   Emit "#EXT-X-PLAYLIST-TYPE:VOD" in the m3u8 header. Forces
	   hls_list_size to 0; the playlist must not change.

       method
	   Use the given HTTP method to create the hls files.

		   ffmpeg -re -i in.ts -f hls -method PUT http://example.com/live/out.m3u8

	   This example will upload all the mpegts segment files to the HTTP
	   server using the HTTP PUT method, and update the m3u8 files every
	   "refresh" times using the same method.  Note that the HTTP server
	   must support the given method for uploading files.

       http_user_agent
	   Override User-Agent field in HTTP header. Applicable only for HTTP
	   output.

       var_stream_map
	   Map string which specifies how to group the audio, video and
	   subtitle streams into different variant streams. The variant stream
	   groups are separated by space.  Expected string format is like this
	   "a:0,v:0 a:1,v:1 ....". Here a:, v:, s: are the keys to specify
	   audio, video and subtitle streams respectively.  Allowed values are
	   0 to 9 (limited just based on practical usage).

	   When there are two or more variant streams, the output filename
	   pattern must contain the string "%v", this string specifies the
	   position of variant stream index in the output media playlist
	   filenames. The string "%v" may be present in the filename or in the
	   last directory name containing the file. If the string is present
	   in the directory name, then sub-directories are created after
	   expanding the directory name pattern. This enables creation of
	   variant streams in subdirectories.

		   ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
		     -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
		     http://example.com/live/out_%v.m3u8

	   This example creates two hls variant streams. The first variant
	   stream will contain video stream of bitrate 1000k and audio stream
	   of bitrate 64k and the second variant stream will contain video
	   stream of bitrate 256k and audio stream of bitrate 32k. Here, two
	   media playlist with file names out_0.m3u8 and out_1.m3u8 will be
	   created.

		   ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k \
		     -map 0:v -map 0:a -map 0:v -f hls -var_stream_map "v:0 a:0 v:1" \
		     http://example.com/live/out_%v.m3u8

	   This example creates three hls variant streams. The first variant
	   stream will be a video only stream with video bitrate 1000k, the
	   second variant stream will be an audio only stream with bitrate 64k
	   and the third variant stream will be a video only stream with
	   bitrate 256k. Here, three media playlist with file names
	   out_0.m3u8, out_1.m3u8 and out_2.m3u8 will be created.

		   ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
		     -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
		     http://example.com/live/vs_%v/out.m3u8

	   This example creates the variant streams in subdirectories. Here,
	   the first media playlist is created at
	   http://example.com/live/vs_0/out.m3u8 and the second one at
	   http://example.com/live/vs_1/out.m3u8.

		   ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k	\
		     -map 0:a -map 0:a -map 0:v -map 0:v -f hls \
		     -var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
		     -master_pl_name master.m3u8 \
		     http://example.com/live/out_%v.m3u8

	   This example creates two audio only and two video only variant
	   streams. In addition to the #EXT-X-STREAM-INF tag for each variant
	   stream in the master playlist, #EXT-X-MEDIA tag is also added for
	   the two audio only variant streams and they are mapped to the two
	   video only variant streams with audio group names 'aud_low' and
	   'aud_high'.

	   By default, a single hls variant containing all the encoded streams
	   is created.

       cc_stream_map
	   Map string which specifies different closed captions groups and
	   their attributes. The closed captions stream groups are separated
	   by space.  Expected string format is like this "ccgroup:<group
	   name>,instreamid:<INSTREAM-ID>,language:<language code> ....".
	   'ccgroup' and 'instreamid' are mandatory attributes. 'language' is
	   an optional attribute.  The closed captions groups configured using
	   this option are mapped to different variant streams by providing
	   the same 'ccgroup' name in the "var_stream_map" string. If
	   "var_stream_map" is not set, then the first available ccgroup in
	   "cc_stream_map" is mapped to the output variant stream. The
	   examples for these two use cases are given below.

		   ffmpeg -re -i in.ts -b:v 1000k -b:a 64k -a53cc 1 -f hls \
		     -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en" \
		     -master_pl_name master.m3u8 \
		     http://example.com/live/out.m3u8

	   This example adds "#EXT-X-MEDIA" tag with "TYPE=CLOSED-CAPTIONS" in
	   the master playlist with group name 'cc', langauge 'en' (english)
	   and INSTREAM-ID 'CC1'. Also, it adds "CLOSED-CAPTIONS" attribute
	   with group name 'cc' for the output variant stream.

		   ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
		     -a53cc:0 1 -a53cc:1 1\
		     -map 0:v -map 0:a -map 0:v -map 0:a -f hls \
		     -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en ccgroup:cc,instreamid:CC2,language:sp" \
		     -var_stream_map "v:0,a:0,ccgroup:cc v:1,a:1,ccgroup:cc" \
		     -master_pl_name master.m3u8 \
		     http://example.com/live/out_%v.m3u8

	   This example adds two "#EXT-X-MEDIA" tags with
	   "TYPE=CLOSED-CAPTIONS" in the master playlist for the INSTREAM-IDs
	   'CC1' and 'CC2'. Also, it adds "CLOSED-CAPTIONS" attribute with
	   group name 'cc' for the two output variant streams.

       master_pl_name
	   Create HLS master playlist with the given name.

		   ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 http://example.com/live/out.m3u8

	   This example creates HLS master playlist with name master.m3u8 and
	   it is published at http://example.com/live/

       master_pl_publish_rate
	   Publish master play list repeatedly every after specified number of
	   segment intervals.

		   ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 \
		   -hls_time 2 -master_pl_publish_rate 30 http://example.com/live/out.m3u8

	   This example creates HLS master playlist with name master.m3u8 and
	   keep publishing it repeatedly every after 30 segments i.e. every
	   after 60s.

       http_persistent
	   Use persistent HTTP connections. Applicable only for HTTP output.

       timeout
	   Set timeout for socket I/O operations. Applicable only for HTTP
	   output.

   ico
       ICO file muxer.

       Microsoft's icon file format (ICO) has some strict limitations that
       should be noted:

       ·   Size cannot exceed 256 pixels in any dimension

       ·   Only BMP and PNG images can be stored

       ·   If a BMP image is used, it must be one of the following pixel
	   formats:

		   BMP Bit Depth      FFmpeg Pixel Format
		   1bit 	      pal8
		   4bit 	      pal8
		   8bit 	      pal8
		   16bit	      rgb555le
		   24bit	      bgr24
		   32bit	      bgra

       ·   If a BMP image is used, it must use the BITMAPINFOHEADER DIB header

       ·   If a PNG image is used, it must use the rgba pixel format

   image2
       Image file muxer.

       The image file muxer writes video frames to image files.

       The output filenames are specified by a pattern, which can be used to
       produce sequentially numbered series of files.  The pattern may contain
       the string "%d" or "%0Nd", this string specifies the position of the
       characters representing a numbering in the filenames. If the form
       "%0Nd" is used, the string representing the number in each filename is
       0-padded to N digits. The literal character '%' can be specified in the
       pattern with the string "%%".

       If the pattern contains "%d" or "%0Nd", the first filename of the file
       list specified will contain the number 1, all the following numbers
       will be sequential.

       The pattern may contain a suffix which is used to automatically
       determine the format of the image files to write.

       For example the pattern "img-%03d.bmp" will specify a sequence of
       filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.
       The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
       form img%-1.jpg, img%-2.jpg, ..., img%-10.jpg, etc.

       Examples

       The following example shows how to use ffmpeg for creating a sequence
       of files img-001.jpeg, img-002.jpeg, ..., taking one image every second
       from the input video:

	       ffmpeg -i in.avi -vsync cfr -r 1 -f image2 'img-%03d.jpeg'

       Note that with ffmpeg, if the format is not specified with the "-f"
       option and the output filename specifies an image file format, the
       image2 muxer is automatically selected, so the previous command can be
       written as:

	       ffmpeg -i in.avi -vsync cfr -r 1 'img-%03d.jpeg'

       Note also that the pattern must not necessarily contain "%d" or "%0Nd",
       for example to create a single image file img.jpeg from the start of
       the input video you can employ the command:

	       ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg

       The strftime option allows you to expand the filename with date and
       time information. Check the documentation of the "strftime()" function
       for the syntax.

       For example to generate image files from the "strftime()"
       "%Y-%m-%d_%H-%M-%S" pattern, the following ffmpeg command can be used:

	       ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"

       You can set the file name with current frame's PTS:

	       ffmpeg -f v4l2 -r 1 -i /dev/video0 -copyts -f image2 -frame_pts true %d.jpg"

       Options

       frame_pts
	   If set to 1, expand the filename with pts from pkt->pts.  Default
	   value is 0.

       start_number
	   Start the sequence from the specified number. Default value is 1.

       update
	   If set to 1, the filename will always be interpreted as just a
	   filename, not a pattern, and the corresponding file will be
	   continuously overwritten with new images. Default value is 0.

       strftime
	   If set to 1, expand the filename with date and time information
	   from "strftime()". Default value is 0.

       The image muxer supports the .Y.U.V image file format. This format is
       special in that that each image frame consists of three files, for each
       of the YUV420P components. To read or write this image file format,
       specify the name of the '.Y' file. The muxer will automatically open
       the '.U' and '.V' files as required.

   matroska
       Matroska container muxer.

       This muxer implements the matroska and webm container specs.

       Metadata

       The recognized metadata settings in this muxer are:

       title
	   Set title name provided to a single track.

       language
	   Specify the language of the track in the Matroska languages form.

	   The language can be either the 3 letters bibliographic ISO-639-2
	   (ISO 639-2/B) form (like "fre" for French), or a language code
	   mixed with a country code for specialities in languages (like "fre-
	   ca" for Canadian French).

       stereo_mode
	   Set stereo 3D video layout of two views in a single video track.

	   The following values are recognized:

	   mono
	       video is not stereo

	   left_right
	       Both views are arranged side by side, Left-eye view is on the
	       left

	   bottom_top
	       Both views are arranged in top-bottom orientation, Left-eye
	       view is at bottom

	   top_bottom
	       Both views are arranged in top-bottom orientation, Left-eye
	       view is on top

	   checkerboard_rl
	       Each view is arranged in a checkerboard interleaved pattern,
	       Left-eye view being first

	   checkerboard_lr
	       Each view is arranged in a checkerboard interleaved pattern,
	       Right-eye view being first

	   row_interleaved_rl
	       Each view is constituted by a row based interleaving, Right-eye
	       view is first row

	   row_interleaved_lr
	       Each view is constituted by a row based interleaving, Left-eye
	       view is first row

	   col_interleaved_rl
	       Both views are arranged in a column based interleaving manner,
	       Right-eye view is first column

	   col_interleaved_lr
	       Both views are arranged in a column based interleaving manner,
	       Left-eye view is first column

	   anaglyph_cyan_red
	       All frames are in anaglyph format viewable through red-cyan
	       filters

	   right_left
	       Both views are arranged side by side, Right-eye view is on the
	       left

	   anaglyph_green_magenta
	       All frames are in anaglyph format viewable through green-
	       magenta filters

	   block_lr
	       Both eyes laced in one Block, Left-eye view is first

	   block_rl
	       Both eyes laced in one Block, Right-eye view is first

       For example a 3D WebM clip can be created using the following command
       line:

	       ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm

       Options

       This muxer supports the following options:

       reserve_index_space
	   By default, this muxer writes the index for seeking (called cues in
	   Matroska terms) at the end of the file, because it cannot know in
	   advance how much space to leave for the index at the beginning of
	   the file. However for some use cases -- e.g.  streaming where
	   seeking is possible but slow -- it is useful to put the index at
	   the beginning of the file.

	   If this option is set to a non-zero value, the muxer will reserve a
	   given amount of space in the file header and then try to write the
	   cues there when the muxing finishes. If the available space does
	   not suffice, muxing will fail. A safe size for most use cases
	   should be about 50kB per hour of video.

	   Note that cues are only written if the output is seekable and this
	   option will have no effect if it is not.

   md5
       MD5 testing format.

       This is a variant of the hash muxer. Unlike that muxer, it defaults to
       using the MD5 hash function.

       Examples

       To compute the MD5 hash of the input converted to raw audio and video,
       and store it in the file out.md5:

	       ffmpeg -i INPUT -f md5 out.md5

       You can print the MD5 to stdout with the command:

	       ffmpeg -i INPUT -f md5 -

       See also the hash and framemd5 muxers.

   mov, mp4, ismv
       MOV/MP4/ISMV (Smooth Streaming) muxer.

       The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4 file
       has all the metadata about all packets stored in one location (written
       at the end of the file, it can be moved to the start for better
       playback by adding faststart to the movflags, or using the qt-faststart
       tool). A fragmented file consists of a number of fragments, where
       packets and metadata about these packets are stored together. Writing a
       fragmented file has the advantage that the file is decodable even if
       the writing is interrupted (while a normal MOV/MP4 is undecodable if it
       is not properly finished), and it requires less memory when writing
       very long files (since writing normal MOV/MP4 files stores info about
       every single packet in memory until the file is closed). The downside
       is that it is less compatible with other applications.

       Options

       Fragmentation is enabled by setting one of the AVOptions that define
       how to cut the file into fragments:

       -moov_size bytes
	   Reserves space for the moov atom at the beginning of the file
	   instead of placing the moov atom at the end. If the space reserved
	   is insufficient, muxing will fail.

       -movflags frag_keyframe
	   Start a new fragment at each video keyframe.

       -frag_duration duration
	   Create fragments that are duration microseconds long.

       -frag_size size
	   Create fragments that contain up to size bytes of payload data.

       -movflags frag_custom
	   Allow the caller to manually choose when to cut fragments, by
	   calling "av_write_frame(ctx, NULL)" to write a fragment with the
	   packets written so far. (This is only useful with other
	   applications integrating libavformat, not from ffmpeg.)

       -min_frag_duration duration
	   Don't create fragments that are shorter than duration microseconds
	   long.

       If more than one condition is specified, fragments are cut when one of
       the specified conditions is fulfilled. The exception to this is
       "-min_frag_duration", which has to be fulfilled for any of the other
       conditions to apply.

       Additionally, the way the output file is written can be adjusted
       through a few other options:

       -movflags empty_moov
	   Write an initial moov atom directly at the start of the file,
	   without describing any samples in it. Generally, an mdat/moov pair
	   is written at the start of the file, as a normal MOV/MP4 file,
	   containing only a short portion of the file. With this option set,
	   there is no initial mdat atom, and the moov atom only describes the
	   tracks but has a zero duration.

	   This option is implicitly set when writing ismv (Smooth Streaming)
	   files.

       -movflags separate_moof
	   Write a separate moof (movie fragment) atom for each track.
	   Normally, packets for all tracks are written in a moof atom (which
	   is slightly more efficient), but with this option set, the muxer
	   writes one moof/mdat pair for each track, making it easier to
	   separate tracks.

	   This option is implicitly set when writing ismv (Smooth Streaming)
	   files.

       -movflags faststart
	   Run a second pass moving the index (moov atom) to the beginning of
	   the file.  This operation can take a while, and will not work in
	   various situations such as fragmented output, thus it is not
	   enabled by default.

       -movflags rtphint
	   Add RTP hinting tracks to the output file.

       -movflags disable_chpl
	   Disable Nero chapter markers (chpl atom).  Normally, both Nero
	   chapters and a QuickTime chapter track are written to the file.
	   With this option set, only the QuickTime chapter track will be
	   written. Nero chapters can cause failures when the file is
	   reprocessed with certain tagging programs, like mp3Tag 2.61a and
	   iTunes 11.3, most likely other versions are affected as well.

       -movflags omit_tfhd_offset
	   Do not write any absolute base_data_offset in tfhd atoms. This
	   avoids tying fragments to absolute byte positions in the
	   file/streams.

       -movflags default_base_moof
	   Similarly to the omit_tfhd_offset, this flag avoids writing the
	   absolute base_data_offset field in tfhd atoms, but does so by using
	   the new default-base-is-moof flag instead. This flag is new from
	   14496-12:2012. This may make the fragments easier to parse in
	   certain circumstances (avoiding basing track fragment location
	   calculations on the implicit end of the previous track fragment).

       -write_tmcd
	   Specify "on" to force writing a timecode track, "off" to disable it
	   and "auto" to write a timecode track only for mov and mp4 output
	   (default).

       -movflags negative_cts_offsets
	   Enables utilization of version 1 of the CTTS box, in which the CTS
	   offsets can be negative. This enables the initial sample to have
	   DTS/CTS of zero, and reduces the need for edit lists for some cases
	   such as video tracks with B-frames. Additionally, eases conformance
	   with the DASH-IF interoperability guidelines.

	   This option is implicitly set when writing ismv (Smooth Streaming)
	   files.

       -write_prft
	   Write producer time reference box (PRFT) with a specified time
	   source for the NTP field in the PRFT box. Set value as wallclock to
	   specify timesource as wallclock time and pts to specify timesource
	   as input packets' PTS values.

	   Setting value to pts is applicable only for a live encoding use
	   case, where PTS values are set as as wallclock time at the source.
	   For example, an encoding use case with decklink capture source
	   where video_pts and audio_pts are set to abs_wallclock.

       Example

       Smooth Streaming content can be pushed in real time to a publishing
       point on IIS with this muxer. Example:

	       ffmpeg -re <<normal input/transcoding options>> -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)

       Audible AAX

       Audible AAX files are encrypted M4B files, and they can be decrypted by
       specifying a 4 byte activation secret.

	       ffmpeg -activation_bytes 1CEB00DA -i test.aax -vn -c:a copy output.mp4

   mp3
       The MP3 muxer writes a raw MP3 stream with the following optional
       features:

       ·   An ID3v2 metadata header at the beginning (enabled by default).
	   Versions 2.3 and 2.4 are supported, the "id3v2_version" private
	   option controls which one is used (3 or 4). Setting "id3v2_version"
	   to 0 disables the ID3v2 header completely.

	   The muxer supports writing attached pictures (APIC frames) to the
	   ID3v2 header.  The pictures are supplied to the muxer in form of a
	   video stream with a single packet. There can be any number of those
	   streams, each will correspond to a single APIC frame.  The stream
	   metadata tags title and comment map to APIC description and picture
	   type respectively. See <http://id3.org/id3v2.4.0-frames> for
	   allowed picture types.

	   Note that the APIC frames must be written at the beginning, so the
	   muxer will buffer the audio frames until it gets all the pictures.
	   It is therefore advised to provide the pictures as soon as possible
	   to avoid excessive buffering.

       ·   A Xing/LAME frame right after the ID3v2 header (if present). It is
	   enabled by default, but will be written only if the output is
	   seekable. The "write_xing" private option can be used to disable
	   it.	The frame contains various information that may be useful to
	   the decoder, like the audio duration or encoder delay.

       ·   A legacy ID3v1 tag at the end of the file (disabled by default). It
	   may be enabled with the "write_id3v1" private option, but as its
	   capabilities are very limited, its usage is not recommended.

       Examples:

       Write an mp3 with an ID3v2.3 header and an ID3v1 footer:

	       ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3

       To attach a picture to an mp3 file select both the audio and the
       picture stream with "map":

	       ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
	       -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3

       Write a "clean" MP3 without any extra features:

	       ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3

   mpegts
       MPEG transport stream muxer.

       This muxer implements ISO 13818-1 and part of ETSI EN 300 468.

       The recognized metadata settings in mpegts muxer are "service_provider"
       and "service_name". If they are not set the default for
       "service_provider" is FFmpeg and the default for "service_name" is
       Service01.

       Options

       The muxer options are:

       mpegts_transport_stream_id integer
	   Set the transport_stream_id. This identifies a transponder in DVB.
	   Default is 0x0001.

       mpegts_original_network_id integer
	   Set the original_network_id. This is unique identifier of a network
	   in DVB. Its main use is in the unique identification of a service
	   through the path Original_Network_ID, Transport_Stream_ID. Default
	   is 0x0001.

       mpegts_service_id integer
	   Set the service_id, also known as program in DVB. Default is
	   0x0001.

       mpegts_service_type integer
	   Set the program service_type. Default is "digital_tv".  Accepts the
	   following options:

	   hex_value
	       Any hexdecimal value between 0x01 to 0xff as defined in ETSI
	       300 468.

	   digital_tv
	       Digital TV service.

	   digital_radio
	       Digital Radio service.

	   teletext
	       Teletext service.

	   advanced_codec_digital_radio
	       Advanced Codec Digital Radio service.

	   mpeg2_digital_hdtv
	       MPEG2 Digital HDTV service.

	   advanced_codec_digital_sdtv
	       Advanced Codec Digital SDTV service.

	   advanced_codec_digital_hdtv
	       Advanced Codec Digital HDTV service.

       mpegts_pmt_start_pid integer
	   Set the first PID for PMT. Default is 0x1000. Max is 0x1f00.

       mpegts_start_pid integer
	   Set the first PID for data packets. Default is 0x0100. Max is
	   0x0f00.

       mpegts_m2ts_mode boolean
	   Enable m2ts mode if set to 1. Default value is "-1" which disables
	   m2ts mode.

       muxrate integer
	   Set a constant muxrate. Default is VBR.

       pes_payload_size integer
	   Set minimum PES packet payload in bytes. Default is 2930.

       mpegts_flags flags
	   Set mpegts flags. Accepts the following options:

	   resend_headers
	       Reemit PAT/PMT before writing the next packet.

	   latm
	       Use LATM packetization for AAC.

	   pat_pmt_at_frames
	       Reemit PAT and PMT at each video frame.

	   system_b
	       Conform to System B (DVB) instead of System A (ATSC).

	   initial_discontinuity
	       Mark the initial packet of each stream as discontinuity.

       resend_headers integer
	   Reemit PAT/PMT before writing the next packet. This option is
	   deprecated: use mpegts_flags instead.

       mpegts_copyts boolean
	   Preserve original timestamps, if value is set to 1. Default value
	   is "-1", which results in shifting timestamps so that they start
	   from 0.

       omit_video_pes_length boolean
	   Omit the PES packet length for video packets. Default is 1 (true).

       pcr_period integer
	   Override the default PCR retransmission time in milliseconds.
	   Ignored if variable muxrate is selected. Default is 20.

       pat_period double
	   Maximum time in seconds between PAT/PMT tables.

       sdt_period double
	   Maximum time in seconds between SDT tables.

       tables_version integer
	   Set PAT, PMT and SDT version (default 0, valid values are from 0 to
	   31, inclusively).  This option allows updating stream structure so
	   that standard consumer may detect the change. To do so, reopen
	   output "AVFormatContext" (in case of API usage) or restart ffmpeg
	   instance, cyclically changing tables_version value:

		   ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
		   ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
		   ...
		   ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
		   ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
		   ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
		   ...

       Example

	       ffmpeg -i file.mpg -c copy \
		    -mpegts_original_network_id 0x1122 \
		    -mpegts_transport_stream_id 0x3344 \
		    -mpegts_service_id 0x5566 \
		    -mpegts_pmt_start_pid 0x1500 \
		    -mpegts_start_pid 0x150 \
		    -metadata service_provider="Some provider" \
		    -metadata service_name="Some Channel" \
		    out.ts

   mxf, mxf_d10
       MXF muxer.

       Options

       The muxer options are:

       store_user_comments bool
	   Set if user comments should be stored if available or never.  IRT
	   D-10 does not allow user comments. The default is thus to write
	   them for mxf but not for mxf_d10

   null
       Null muxer.

       This muxer does not generate any output file, it is mainly useful for
       testing or benchmarking purposes.

       For example to benchmark decoding with ffmpeg you can use the command:

	       ffmpeg -benchmark -i INPUT -f null out.null

       Note that the above command does not read or write the out.null file,
       but specifying the output file is required by the ffmpeg syntax.

       Alternatively you can write the command as:

	       ffmpeg -benchmark -i INPUT -f null -

   nut
       -syncpoints flags
	   Change the syncpoint usage in nut:

	   default use the normal low-overhead seeking aids.
	   none do not use the syncpoints at all, reducing the overhead but
	   making the stream non-seekable;
		   Use of this option is not recommended, as the resulting files are very damage
		   sensitive and seeking is not possible. Also in general the overhead from
		   syncpoints is negligible. Note, -C<write_index> 0 can be used to disable
		   all growing data tables, allowing to mux endless streams with limited memory
		   and without these disadvantages.

	   timestamped extend the syncpoint with a wallclock field.

	   The none and timestamped flags are experimental.

       -write_index bool
	   Write index at the end, the default is to write an index.

	       ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor

   ogg
       Ogg container muxer.

       -page_duration duration
	   Preferred page duration, in microseconds. The muxer will attempt to
	   create pages that are approximately duration microseconds long.
	   This allows the user to compromise between seek granularity and
	   container overhead. The default is 1 second. A value of 0 will fill
	   all segments, making pages as large as possible. A value of 1 will
	   effectively use 1 packet-per-page in most situations, giving a
	   small seek granularity at the cost of additional container
	   overhead.

       -serial_offset value
	   Serial value from which to set the streams serial number.  Setting
	   it to different and sufficiently large values ensures that the
	   produced ogg files can be safely chained.

   segment, stream_segment, ssegment
       Basic stream segmenter.

       This muxer outputs streams to a number of separate files of nearly
       fixed duration. Output filename pattern can be set in a fashion similar
       to image2, or by using a "strftime" template if the strftime option is
       enabled.

       "stream_segment" is a variant of the muxer used to write to streaming
       output formats, i.e. which do not require global headers, and is
       recommended for outputting e.g. to MPEG transport stream segments.
       "ssegment" is a shorter alias for "stream_segment".

       Every segment starts with a keyframe of the selected reference stream,
       which is set through the reference_stream option.

       Note that if you want accurate splitting for a video file, you need to
       make the input key frames correspond to the exact splitting times
       expected by the segmenter, or the segment muxer will start the new
       segment with the key frame found next after the specified start time.

       The segment muxer works best with a single constant frame rate video.

       Optionally it can generate a list of the created segments, by setting
       the option segment_list. The list type is specified by the
       segment_list_type option. The entry filenames in the segment list are
       set by default to the basename of the corresponding segment files.

       See also the hls muxer, which provides a more specific implementation
       for HLS segmentation.

       Options

       The segment muxer supports the following options:

       increment_tc 1|0
	   if set to 1, increment timecode between each segment If this is
	   selected, the input need to have a timecode in the first video
	   stream. Default value is 0.

       reference_stream specifier
	   Set the reference stream, as specified by the string specifier.  If
	   specifier is set to "auto", the reference is chosen automatically.
	   Otherwise it must be a stream specifier (see the ``Stream
	   specifiers'' chapter in the ffmpeg manual) which specifies the
	   reference stream. The default value is "auto".

       segment_format format
	   Override the inner container format, by default it is guessed by
	   the filename extension.

       segment_format_options options_list
	   Set output format options using a :-separated list of key=value
	   parameters. Values containing the ":" special character must be
	   escaped.

       segment_list name
	   Generate also a listfile named name. If not specified no listfile
	   is generated.

       segment_list_flags flags
	   Set flags affecting the segment list generation.

	   It currently supports the following flags:

	   cache
	       Allow caching (only affects M3U8 list files).

	   live
	       Allow live-friendly file generation.

       segment_list_size size
	   Update the list file so that it contains at most size segments. If
	   0 the list file will contain all the segments. Default value is 0.

       segment_list_entry_prefix prefix
	   Prepend prefix to each entry. Useful to generate absolute paths.
	   By default no prefix is applied.

       segment_list_type type
	   Select the listing format.

	   The following values are recognized:

	   flat
	       Generate a flat list for the created segments, one segment per
	       line.

	   csv, ext
	       Generate a list for the created segments, one segment per line,
	       each line matching the format (comma-separated values):

		       <segment_filename>,<segment_start_time>,<segment_end_time>

	       segment_filename is the name of the output file generated by
	       the muxer according to the provided pattern. CSV escaping
	       (according to RFC4180) is applied if required.

	       segment_start_time and segment_end_time specify the segment
	       start and end time expressed in seconds.

	       A list file with the suffix ".csv" or ".ext" will auto-select
	       this format.

	       ext is deprecated in favor or csv.

	   ffconcat
	       Generate an ffconcat file for the created segments. The
	       resulting file can be read using the FFmpeg concat demuxer.

	       A list file with the suffix ".ffcat" or ".ffconcat" will auto-
	       select this format.

	   m3u8
	       Generate an extended M3U8 file, version 3, compliant with
	       <http://tools.ietf.org/id/draft-pantos-http-live-streaming>.

	       A list file with the suffix ".m3u8" will auto-select this
	       format.

	   If not specified the type is guessed from the list file name
	   suffix.

       segment_time time
	   Set segment duration to time, the value must be a duration
	   specification. Default value is "2". See also the segment_times
	   option.

	   Note that splitting may not be accurate, unless you force the
	   reference stream key-frames at the given time. See the introductory
	   notice and the examples below.

       segment_atclocktime 1|0
	   If set to "1" split at regular clock time intervals starting from
	   00:00 o'clock. The time value specified in segment_time is used for
	   setting the length of the splitting interval.

	   For example with segment_time set to "900" this makes it possible
	   to create files at 12:00 o'clock, 12:15, 12:30, etc.

	   Default value is "0".

       segment_clocktime_offset duration
	   Delay the segment splitting times with the specified duration when
	   using segment_atclocktime.

	   For example with segment_time set to "900" and
	   segment_clocktime_offset set to "300" this makes it possible to
	   create files at 12:05, 12:20, 12:35, etc.

	   Default value is "0".

       segment_clocktime_wrap_duration duration
	   Force the segmenter to only start a new segment if a packet reaches
	   the muxer within the specified duration after the segmenting clock
	   time. This way you can make the segmenter more resilient to
	   backward local time jumps, such as leap seconds or transition to
	   standard time from daylight savings time.

	   Default is the maximum possible duration which means starting a new
	   segment regardless of the elapsed time since the last clock time.

       segment_time_delta delta
	   Specify the accuracy time when selecting the start time for a
	   segment, expressed as a duration specification. Default value is
	   "0".

	   When delta is specified a key-frame will start a new segment if its
	   PTS satisfies the relation:

		   PTS >= start_time - time_delta

	   This option is useful when splitting video content, which is always
	   split at GOP boundaries, in case a key frame is found just before
	   the specified split time.

	   In particular may be used in combination with the ffmpeg option
	   force_key_frames. The key frame times specified by force_key_frames
	   may not be set accurately because of rounding issues, with the
	   consequence that a key frame time may result set just before the
	   specified time. For constant frame rate videos a value of
	   1/(2*frame_rate) should address the worst case mismatch between the
	   specified time and the time set by force_key_frames.

       segment_times times
	   Specify a list of split points. times contains a list of comma
	   separated duration specifications, in increasing order. See also
	   the segment_time option.

       segment_frames frames
	   Specify a list of split video frame numbers. frames contains a list
	   of comma separated integer numbers, in increasing order.

	   This option specifies to start a new segment whenever a reference
	   stream key frame is found and the sequential number (starting from
	   0) of the frame is greater or equal to the next value in the list.

       segment_wrap limit
	   Wrap around segment index once it reaches limit.

       segment_start_number number
	   Set the sequence number of the first segment. Defaults to 0.

       strftime 1|0
	   Use the "strftime" function to define the name of the new segments
	   to write. If this is selected, the output segment name must contain
	   a "strftime" function template. Default value is 0.

       break_non_keyframes 1|0
	   If enabled, allow segments to start on frames other than keyframes.
	   This improves behavior on some players when the time between
	   keyframes is inconsistent, but may make things worse on others, and
	   can cause some oddities during seeking. Defaults to 0.

       reset_timestamps 1|0
	   Reset timestamps at the beginning of each segment, so that each
	   segment will start with near-zero timestamps. It is meant to ease
	   the playback of the generated segments. May not work with some
	   combinations of muxers/codecs. It is set to 0 by default.

       initial_offset offset
	   Specify timestamp offset to apply to the output packet timestamps.
	   The argument must be a time duration specification, and defaults to
	   0.

       write_empty_segments 1|0
	   If enabled, write an empty segment if there are no packets during
	   the period a segment would usually span. Otherwise, the segment
	   will be filled with the next packet written. Defaults to 0.

       Make sure to require a closed GOP when encoding and to set the GOP size
       to fit your segment time constraint.

       Examples

       ·   Remux the content of file in.mkv to a list of segments out-000.nut,
	   out-001.nut, etc., and write the list of generated segments to
	   out.list:

		   ffmpeg -i in.mkv -codec hevc -flags +cgop -g 60 -map 0 -f segment -segment_list out.list out%03d.nut

       ·   Segment input and set output format options for the output
	   segments:

		   ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4

       ·   Segment the input file according to the split points specified by
	   the segment_times option:

		   ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 out%03d.nut

       ·   Use the ffmpeg force_key_frames option to force key frames in the
	   input at the specified location, together with the segment option
	   segment_time_delta to account for possible roundings operated when
	   setting key frame times.

		   ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
		   -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut

	   In order to force key frames on the input file, transcoding is
	   required.

       ·   Segment the input file by splitting the input file according to the
	   frame numbers sequence specified with the segment_frames option:

		   ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut

       ·   Convert the in.mkv to TS segments using the "libx264" and "aac"
	   encoders:

		   ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a aac -f ssegment -segment_list out.list out%03d.ts

       ·   Segment the input file, and create an M3U8 live playlist (can be
	   used as live HLS source):

		   ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
		   -segment_list_flags +live -segment_time 10 out%03d.mkv

   smoothstreaming
       Smooth Streaming muxer generates a set of files (Manifest, chunks)
       suitable for serving with conventional web server.

       window_size
	   Specify the number of fragments kept in the manifest. Default 0
	   (keep all).

       extra_window_size
	   Specify the number of fragments kept outside of the manifest before
	   removing from disk. Default 5.

       lookahead_count
	   Specify the number of lookahead fragments. Default 2.

       min_frag_duration
	   Specify the minimum fragment duration (in microseconds). Default
	   5000000.

       remove_at_exit
	   Specify whether to remove all fragments when finished. Default 0
	   (do not remove).

   fifo
       The fifo pseudo-muxer allows the separation of encoding and muxing by
       using first-in-first-out queue and running the actual muxer in a
       separate thread. This is especially useful in combination with the tee
       muxer and can be used to send data to several destinations with
       different reliability/writing speed/latency.

       API users should be aware that callback functions (interrupt_callback,
       io_open and io_close) used within its AVFormatContext must be thread-
       safe.

       The behavior of the fifo muxer if the queue fills up or if the output
       fails is selectable,

       ·   output can be transparently restarted with configurable delay
	   between retries based on real time or time of the processed stream.

       ·   encoding can be blocked during temporary failure, or continue
	   transparently dropping packets in case fifo queue fills up.

       fifo_format
	   Specify the format name. Useful if it cannot be guessed from the
	   output name suffix.

       queue_size
	   Specify size of the queue (number of packets). Default value is 60.

       format_opts
	   Specify format options for the underlying muxer. Muxer options can
	   be specified as a list of key=value pairs separated by ':'.

       drop_pkts_on_overflow bool
	   If set to 1 (true), in case the fifo queue fills up, packets will
	   be dropped rather than blocking the encoder. This makes it possible
	   to continue streaming without delaying the input, at the cost of
	   omitting part of the stream. By default this option is set to 0
	   (false), so in such cases the encoder will be blocked until the
	   muxer processes some of the packets and none of them is lost.

       attempt_recovery bool
	   If failure occurs, attempt to recover the output. This is
	   especially useful when used with network output, since it makes it
	   possible to restart streaming transparently.  By default this
	   option is set to 0 (false).

       max_recovery_attempts
	   Sets maximum number of successive unsuccessful recovery attempts
	   after which the output fails permanently. By default this option is
	   set to 0 (unlimited).

       recovery_wait_time duration
	   Waiting time before the next recovery attempt after previous
	   unsuccessful recovery attempt. Default value is 5 seconds.

       recovery_wait_streamtime bool
	   If set to 0 (false), the real time is used when waiting for the
	   recovery attempt (i.e. the recovery will be attempted after at
	   least recovery_wait_time seconds).  If set to 1 (true), the time of
	   the processed stream is taken into account instead (i.e. the
	   recovery will be attempted after at least recovery_wait_time
	   seconds of the stream is omitted).  By default, this option is set
	   to 0 (false).

       recover_any_error bool
	   If set to 1 (true), recovery will be attempted regardless of type
	   of the error causing the failure. By default this option is set to
	   0 (false) and in case of certain (usually permanent) errors the
	   recovery is not attempted even when attempt_recovery is set to 1.

       restart_with_keyframe bool
	   Specify whether to wait for the keyframe after recovering from
	   queue overflow or failure. This option is set to 0 (false) by
	   default.

       Examples

       ·   Stream something to rtmp server, continue processing the stream at
	   real-time rate even in case of temporary failure (network outage)
	   and attempt to recover streaming every second indefinitely.

		   ffmpeg -re -i ... -c:v libx264 -c:a aac -f fifo -fifo_format flv -map 0:v -map 0:a
		     -drop_pkts_on_overflow 1 -attempt_recovery 1 -recovery_wait_time 1 rtmp://example.com/live/stream_name

   tee
       The tee muxer can be used to write the same data to several outputs,
       such as files or streams.  It can be used, for example, to stream a
       video over a network and save it to disk at the same time.

       It is different from specifying several outputs to the ffmpeg command-
       line tool. With the tee muxer, the audio and video data will be encoded
       only once.  With conventional multiple outputs, multiple encoding
       operations in parallel are initiated, which can be a very expensive
       process. The tee muxer is not useful when using the libavformat API
       directly because it is then possible to feed the same packets to
       several muxers directly.

       Since the tee muxer does not represent any particular output format,
       ffmpeg cannot auto-select output streams. So all streams intended for
       output must be specified using "-map". See the examples below.

       Some encoders may need different options depending on the output
       format; the auto-detection of this can not work with the tee muxer, so
       they need to be explicitly specified.  The main example is the
       global_header flag.

       The slave outputs are specified in the file name given to the muxer,
       separated by '|'. If any of the slave name contains the '|' separator,
       leading or trailing spaces or any special character, those must be
       escaped (see the "Quoting and escaping" section in the ffmpeg-utils(1)
       manual).

       Options

       use_fifo bool
	   If set to 1, slave outputs will be processed in separate threads
	   using the fifo muxer. This allows to compensate for different
	   speed/latency/reliability of outputs and setup transparent
	   recovery. By default this feature is turned off.

       fifo_options
	   Options to pass to fifo pseudo-muxer instances. See fifo.

       Muxer options can be specified for each slave by prepending them as a
       list of key=value pairs separated by ':', between square brackets. If
       the options values contain a special character or the ':' separator,
       they must be escaped; note that this is a second level escaping.

       The following special options are also recognized:

       f   Specify the format name. Required if it cannot be guessed from the
	   output URL.

       bsfs[/spec]
	   Specify a list of bitstream filters to apply to the specified
	   output.

	   It is possible to specify to which streams a given bitstream filter
	   applies, by appending a stream specifier to the option separated by
	   "/". spec must be a stream specifier (see Format stream
	   specifiers).

	   If the stream specifier is not specified, the bitstream filters
	   will be applied to all streams in the output. This will cause that
	   output operation to fail if the output contains streams to which
	   the bitstream filter cannot be applied e.g. "h264_mp4toannexb"
	   being applied to an output containing an audio stream.

	   Options for a bitstream filter must be specified in the form of
	   "opt=value".

	   Several bitstream filters can be specified, separated by ",".

       use_fifo bool
	   This allows to override tee muxer use_fifo option for individual
	   slave muxer.

       fifo_options
	   This allows to override tee muxer fifo_options for individual slave
	   muxer.  See fifo.

       select
	   Select the streams that should be mapped to the slave output,
	   specified by a stream specifier. If not specified, this defaults to
	   all the mapped streams. This will cause that output operation to
	   fail if the output format does not accept all mapped streams.

	   You may use multiple stream specifiers separated by commas (",")
	   e.g.: "a:0,v"

       onfail
	   Specify behaviour on output failure. This can be set to either
	   "abort" (which is default) or "ignore". "abort" will cause whole
	   process to fail in case of failure on this slave output. "ignore"
	   will ignore failure on this output, so other outputs will continue
	   without being affected.

       Examples

       ·   Encode something and both archive it in a WebM file and stream it
	   as MPEG-TS over UDP:

		   ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
		     "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"

       ·   As above, but continue streaming even if output to local file fails
	   (for example local drive fills up):

		   ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
		     "[onfail=ignore]archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"

       ·   Use ffmpeg to encode the input, and send the output to three
	   different destinations. The "dump_extra" bitstream filter is used
	   to add extradata information to all the output video keyframes
	   packets, as requested by the MPEG-TS format. The select option is
	   applied to out.aac in order to make it contain only audio packets.

		   ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
			  -f tee "[bsfs/v=dump_extra=freq=keyframe]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"

       ·   As above, but select only stream "a:1" for the audio output. Note
	   that a second level escaping must be performed, as ":" is a special
	   character used to separate options.

		   ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
			  -f tee "[bsfs/v=dump_extra=freq=keyframe]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"

   webm_dash_manifest
       WebM DASH Manifest muxer.

       This muxer implements the WebM DASH Manifest specification to generate
       the DASH manifest XML. It also supports manifest generation for DASH
       live streams.

       For more information see:

       ·   WebM DASH Specification:
	   <https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification>

       ·   ISO DASH Specification:
	   <http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip>

       Options

       This muxer supports the following options:

       adaptation_sets
	   This option has the following syntax: "id=x,streams=a,b,c
	   id=y,streams=d,e" where x and y are the unique identifiers of the
	   adaptation sets and a,b,c,d and e are the indices of the
	   corresponding audio and video streams. Any number of adaptation
	   sets can be added using this option.

       live
	   Set this to 1 to create a live stream DASH Manifest. Default: 0.

       chunk_start_index
	   Start index of the first chunk. This will go in the startNumber
	   attribute of the SegmentTemplate element in the manifest. Default:
	   0.

       chunk_duration_ms
	   Duration of each chunk in milliseconds. This will go in the
	   duration attribute of the SegmentTemplate element in the manifest.
	   Default: 1000.

       utc_timing_url
	   URL of the page that will return the UTC timestamp in ISO format.
	   This will go in the value attribute of the UTCTiming element in the
	   manifest.  Default: None.

       time_shift_buffer_depth
	   Smallest time (in seconds) shifting buffer for which any
	   Representation is guaranteed to be available. This will go in the
	   timeShiftBufferDepth attribute of the MPD element. Default: 60.

       minimum_update_period
	   Minimum update period (in seconds) of the manifest. This will go in
	   the minimumUpdatePeriod attribute of the MPD element. Default: 0.

       Example

	       ffmpeg -f webm_dash_manifest -i video1.webm \
		      -f webm_dash_manifest -i video2.webm \
		      -f webm_dash_manifest -i audio1.webm \
		      -f webm_dash_manifest -i audio2.webm \
		      -map 0 -map 1 -map 2 -map 3 \
		      -c copy \
		      -f webm_dash_manifest \
		      -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \
		      manifest.xml

   webm_chunk
       WebM Live Chunk Muxer.

       This muxer writes out WebM headers and chunks as separate files which
       can be consumed by clients that support WebM Live streams via DASH.

       Options

       This muxer supports the following options:

       chunk_start_index
	   Index of the first chunk (defaults to 0).

       header
	   Filename of the header where the initialization data will be
	   written.

       audio_chunk_duration
	   Duration of each audio chunk in milliseconds (defaults to 5000).

       Example

	       ffmpeg -f v4l2 -i /dev/video0 \
		      -f alsa -i hw:0 \
		      -map 0:0 \
		      -c:v libvpx-vp9 \
		      -s 640x360 -keyint_min 30 -g 30 \
		      -f webm_chunk \
		      -header webm_live_video_360.hdr \
		      -chunk_start_index 1 \
		      webm_live_video_360_%d.chk \
		      -map 1:0 \
		      -c:a libvorbis \
		      -b:a 128k \
		      -f webm_chunk \
		      -header webm_live_audio_128.hdr \
		      -chunk_start_index 1 \
		      -audio_chunk_duration 1000 \
		      webm_live_audio_128_%d.chk

METADATA
       FFmpeg is able to dump metadata from media files into a simple
       UTF-8-encoded INI-like text file and then load it back using the
       metadata muxer/demuxer.

       The file format is as follows:

       1.  A file consists of a header and a number of metadata tags divided
	   into sections, each on its own line.

       2.  The header is a ;FFMETADATA string, followed by a version number
	   (now 1).

       3.  Metadata tags are of the form key=value

       4.  Immediately after header follows global metadata

       5.  After global metadata there may be sections with
	   per-stream/per-chapter metadata.

       6.  A section starts with the section name in uppercase (i.e. STREAM or
	   CHAPTER) in brackets ([, ]) and ends with next section or end of
	   file.

       7.  At the beginning of a chapter section there may be an optional
	   timebase to be used for start/end values. It must be in form
	   TIMEBASE=num/den, where num and den are integers. If the timebase
	   is missing then start/end times are assumed to be in milliseconds.

	   Next a chapter section must contain chapter start and end times in
	   form START=num, END=num, where num is a positive integer.

       8.  Empty lines and lines starting with ; or # are ignored.

       9.  Metadata keys or values containing special characters (=, ;, #, \
	   and a newline) must be escaped with a backslash \.

       10. Note that whitespace in metadata (e.g. foo = bar) is considered to
	   be a part of the tag (in the example above key is foo , value is
	    bar).

       A ffmetadata file might look like this:

	       ;FFMETADATA1
	       title=bike\\shed
	       ;this is a comment
	       artist=FFmpeg troll team

	       [CHAPTER]
	       TIMEBASE=1/1000
	       START=0
	       #chapter ends at 0:01:00
	       END=60000
	       title=chapter \#1
	       [STREAM]
	       title=multi\
	       line

       By using the ffmetadata muxer and demuxer it is possible to extract
       metadata from an input file to an ffmetadata file, and then transcode
       the file into an output file with the edited ffmetadata file.

       Extracting an ffmetadata file with ffmpeg goes as follows:

	       ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE

       Reinserting edited metadata information from the FFMETADATAFILE file
       can be done as:

	       ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT

SEE ALSO
       ffmpeg(1), ffplay(1), ffprobe(1), libavformat(3)

AUTHORS
       The FFmpeg developers.

       For details about the authorship, see the Git history of the project
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
       the FFmpeg source directory, or browsing the online repository at
       <http://source.ffmpeg.org>.

       Maintainers for the specific components are listed in the file
       MAINTAINERS in the source code tree.

							     FFMPEG-FORMATS(1)
