4 Muxers are configured elements in FFmpeg which allow writing
5 multimedia streams to a particular type of file.
7 When you configure your FFmpeg build, all the supported muxers
8 are enabled by default. You can list all available muxers using the
9 configure option @code{--list-muxers}.
11 You can disable all the muxers with the configure option
12 @code{--disable-muxers} and selectively enable / disable single muxers
13 with the options @code{--enable-muxer=@var{MUXER}} /
14 @code{--disable-muxer=@var{MUXER}}.
16 The option @code{-formats} of the ff* tools will display the list of
19 A description of some of the currently available muxers follows.
24 Audio Interchange File Format muxer.
26 It accepts the following options:
30 Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).
33 Select ID3v2 version to write. Currently only version 3 and 4 (aka.
34 ID3v2.3 and ID3v2.4) are supported. The default is version 4.
41 CRC (Cyclic Redundancy Check) testing format.
43 This muxer computes and prints the Adler-32 CRC of all the input audio
44 and video frames. By default audio frames are converted to signed
45 16-bit raw audio and video frames to raw video before computing the
48 The output of the muxer consists of a single line of the form:
49 CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
50 8 digits containing the CRC for all the decoded input frames.
52 For example to compute the CRC of the input, and store it in the file
55 ffmpeg -i INPUT -f crc out.crc
58 You can print the CRC to stdout with the command:
60 ffmpeg -i INPUT -f crc -
63 You can select the output format of each frame with @command{ffmpeg} by
64 specifying the audio and video codec and format. For example to
65 compute the CRC of the input audio converted to PCM unsigned 8-bit
66 and the input video converted to MPEG-2 video, use the command:
68 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
71 See also the @ref{framecrc} muxer.
76 Per-packet CRC (Cyclic Redundancy Check) testing format.
78 This muxer computes and prints the Adler-32 CRC for each audio
79 and video packet. By default audio frames are converted to signed
80 16-bit raw audio and video frames to raw video before computing the
83 The output of the muxer consists of a line for each audio and video
86 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
89 @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
92 For example to compute the CRC of the audio and video frames in
93 @file{INPUT}, converted to raw audio and video packets, and store it
94 in the file @file{out.crc}:
96 ffmpeg -i INPUT -f framecrc out.crc
99 To print the information to stdout, use the command:
101 ffmpeg -i INPUT -f framecrc -
104 With @command{ffmpeg}, you can select the output format to which the
105 audio and video frames are encoded before computing the CRC for each
106 packet by specifying the audio and video codec. For example, to
107 compute the CRC of each decoded input audio frame converted to PCM
108 unsigned 8-bit and of each decoded input video frame converted to
109 MPEG-2 video, use the command:
111 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
114 See also the @ref{crc} muxer.
119 Per-packet MD5 testing format.
121 This muxer computes and prints the MD5 hash for each audio
122 and video packet. By default audio frames are converted to signed
123 16-bit raw audio and video frames to raw video before computing the
126 The output of the muxer consists of a line for each audio and video
129 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
132 @var{MD5} is a hexadecimal number representing the computed MD5 hash
135 For example to compute the MD5 of the audio and video frames in
136 @file{INPUT}, converted to raw audio and video packets, and store it
137 in the file @file{out.md5}:
139 ffmpeg -i INPUT -f framemd5 out.md5
142 To print the information to stdout, use the command:
144 ffmpeg -i INPUT -f framemd5 -
147 See also the @ref{md5} muxer.
154 It accepts the following options:
158 Set the number of times to loop the output. Use @code{-1} for no loop, @code{0}
159 for looping indefinitely (default).
162 Force the delay (expressed in centiseconds) after the last frame. Each frame
163 ends with a delay until the next frame. The default is @code{-1}, which is a
164 special value to tell the muxer to re-use the previous delay. In case of a
165 loop, you might want to customize this value to mark a pause for instance.
168 For example, to encode a gif looping 10 times, with a 5 seconds delay between
171 ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif
174 Note 1: if you wish to extract the frames in separate GIF files, you need to
175 force the @ref{image2} muxer:
177 ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"
180 Note 2: the GIF format has a very small time base: the delay between two frames
181 can not be smaller than one centi second.
186 Apple HTTP Live Streaming muxer that segments MPEG-TS according to
187 the HTTP Live Streaming specification.
189 It creates a playlist file and numbered segment files. The output
190 filename specifies the playlist filename; the segment filenames
191 receive the same basename as the playlist, a sequential number and
195 ffmpeg -i in.nut out.m3u8
199 @item -hls_time @var{seconds}
200 Set the segment length in seconds.
201 @item -hls_list_size @var{size}
202 Set the maximum number of playlist entries.
203 @item -hls_wrap @var{wrap}
204 Set the number after which index wraps.
205 @item -start_number @var{number}
206 Start the sequence from @var{number}.
214 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
218 Size cannot exceed 256 pixels in any dimension
221 Only BMP and PNG images can be stored
224 If a BMP image is used, it must be one of the following pixel formats:
226 BMP Bit Depth FFmpeg Pixel Format
236 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
239 If a PNG image is used, it must use the rgba pixel format
247 The image file muxer writes video frames to image files.
249 The output filenames are specified by a pattern, which can be used to
250 produce sequentially numbered series of files.
251 The pattern may contain the string "%d" or "%0@var{N}d", this string
252 specifies the position of the characters representing a numbering in
253 the filenames. If the form "%0@var{N}d" is used, the string
254 representing the number in each filename is 0-padded to @var{N}
255 digits. The literal character '%' can be specified in the pattern with
258 If the pattern contains "%d" or "%0@var{N}d", the first filename of
259 the file list specified will contain the number 1, all the following
260 numbers will be sequential.
262 The pattern may contain a suffix which is used to automatically
263 determine the format of the image files to write.
265 For example the pattern "img-%03d.bmp" will specify a sequence of
266 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
267 @file{img-010.bmp}, etc.
268 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
269 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
272 The following example shows how to use @command{ffmpeg} for creating a
273 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
274 taking one image every second from the input video:
276 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
279 Note that with @command{ffmpeg}, if the format is not specified with the
280 @code{-f} option and the output filename specifies an image file
281 format, the image2 muxer is automatically selected, so the previous
282 command can be written as:
284 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
287 Note also that the pattern must not necessarily contain "%d" or
288 "%0@var{N}d", for example to create a single image file
289 @file{img.jpeg} from the input video you can employ the command:
291 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
295 @item start_number @var{number}
296 Start the sequence from @var{number}. Default value is 1. Must be a
299 @item -update @var{number}
300 If @var{number} is nonzero, the filename will always be interpreted as just a
301 filename, not a pattern, and this file will be continuously overwritten with new
306 The image muxer supports the .Y.U.V image file format. This format is
307 special in that that each image frame consists of three files, for
308 each of the YUV420P components. To read or write this image file format,
309 specify the name of the '.Y' file. The muxer will automatically open the
310 '.U' and '.V' files as required.
314 Matroska container muxer.
316 This muxer implements the matroska and webm container specs.
318 The recognized metadata settings in this muxer are:
322 @item title=@var{title name}
323 Name provided to a single track
328 @item language=@var{language name}
329 Specifies the language of the track in the Matroska languages form
334 @item stereo_mode=@var{mode}
335 Stereo 3D video layout of two views in a single video track
340 Both views are arranged side by side, Left-eye view is on the left
342 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
344 Both views are arranged in top-bottom orientation, Left-eye view is on top
345 @item checkerboard_rl
346 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
347 @item checkerboard_lr
348 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
349 @item row_interleaved_rl
350 Each view is constituted by a row based interleaving, Right-eye view is first row
351 @item row_interleaved_lr
352 Each view is constituted by a row based interleaving, Left-eye view is first row
353 @item col_interleaved_rl
354 Both views are arranged in a column based interleaving manner, Right-eye view is first column
355 @item col_interleaved_lr
356 Both views are arranged in a column based interleaving manner, Left-eye view is first column
357 @item anaglyph_cyan_red
358 All frames are in anaglyph format viewable through red-cyan filters
360 Both views are arranged side by side, Right-eye view is on the left
361 @item anaglyph_green_magenta
362 All frames are in anaglyph format viewable through green-magenta filters
364 Both eyes laced in one Block, Left-eye view is first
366 Both eyes laced in one Block, Right-eye view is first
370 For example a 3D WebM clip can be created using the following command line:
372 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
375 This muxer supports the following options:
379 @item reserve_index_space
380 By default, this muxer writes the index for seeking (called cues in Matroska
381 terms) at the end of the file, because it cannot know in advance how much space
382 to leave for the index at the beginning of the file. However for some use cases
383 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
384 index at the beginning of the file.
386 If this option is set to a non-zero value, the muxer will reserve a given amount
387 of space in the file header and then try to write the cues there when the muxing
388 finishes. If the available space does not suffice, muxing will fail. A safe size
389 for most use cases should be about 50kB per hour of video.
391 Note that cues are only written if the output is seekable and this option will
392 have no effect if it is not.
401 This muxer computes and prints the MD5 hash of all the input audio
402 and video frames. By default audio frames are converted to signed
403 16-bit raw audio and video frames to raw video before computing the
406 The output of the muxer consists of a single line of the form:
407 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
408 the computed MD5 hash.
410 For example to compute the MD5 hash of the input converted to raw
411 audio and video, and store it in the file @file{out.md5}:
413 ffmpeg -i INPUT -f md5 out.md5
416 You can print the MD5 to stdout with the command:
418 ffmpeg -i INPUT -f md5 -
421 See also the @ref{framemd5} muxer.
423 @section mov/mp4/ismv
425 MOV/MP4/ISMV (Smooth Streaming) muxer.
427 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
428 file has all the metadata about all packets stored in one location
429 (written at the end of the file, it can be moved to the start for
430 better playback by adding @var{faststart} to the @var{movflags}, or
431 using the @command{qt-faststart} tool). A fragmented
432 file consists of a number of fragments, where packets and metadata
433 about these packets are stored together. Writing a fragmented
434 file has the advantage that the file is decodable even if the
435 writing is interrupted (while a normal MOV/MP4 is undecodable if
436 it is not properly finished), and it requires less memory when writing
437 very long files (since writing normal MOV/MP4 files stores info about
438 every single packet in memory until the file is closed). The downside
439 is that it is less compatible with other applications.
441 Fragmentation is enabled by setting one of the AVOptions that define
442 how to cut the file into fragments:
445 @item -moov_size @var{bytes}
446 Reserves space for the moov atom at the beginning of the file instead of placing the
447 moov atom at the end. If the space reserved is insufficient, muxing will fail.
448 @item -movflags frag_keyframe
449 Start a new fragment at each video keyframe.
450 @item -frag_duration @var{duration}
451 Create fragments that are @var{duration} microseconds long.
452 @item -frag_size @var{size}
453 Create fragments that contain up to @var{size} bytes of payload data.
454 @item -movflags frag_custom
455 Allow the caller to manually choose when to cut fragments, by
456 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
457 the packets written so far. (This is only useful with other
458 applications integrating libavformat, not from @command{ffmpeg}.)
459 @item -min_frag_duration @var{duration}
460 Don't create fragments that are shorter than @var{duration} microseconds long.
463 If more than one condition is specified, fragments are cut when
464 one of the specified conditions is fulfilled. The exception to this is
465 @code{-min_frag_duration}, which has to be fulfilled for any of the other
468 Additionally, the way the output file is written can be adjusted
469 through a few other options:
472 @item -movflags empty_moov
473 Write an initial moov atom directly at the start of the file, without
474 describing any samples in it. Generally, an mdat/moov pair is written
475 at the start of the file, as a normal MOV/MP4 file, containing only
476 a short portion of the file. With this option set, there is no initial
477 mdat atom, and the moov atom only describes the tracks but has
480 Files written with this option set do not work in QuickTime.
481 This option is implicitly set when writing ismv (Smooth Streaming) files.
482 @item -movflags separate_moof
483 Write a separate moof (movie fragment) atom for each track. Normally,
484 packets for all tracks are written in a moof atom (which is slightly
485 more efficient), but with this option set, the muxer writes one moof/mdat
486 pair for each track, making it easier to separate tracks.
488 This option is implicitly set when writing ismv (Smooth Streaming) files.
489 @item -movflags faststart
490 Run a second pass moving the index (moov atom) to the beginning of the file.
491 This operation can take a while, and will not work in various situations such
492 as fragmented output, thus it is not enabled by default.
493 @item -movflags rtphint
494 Add RTP hinting tracks to the output file.
497 Smooth Streaming content can be pushed in real time to a publishing
498 point on IIS with this muxer. Example:
500 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
505 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
506 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
507 @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
508 not written by default, but may be enabled with the @code{write_id3v1} option.
510 For seekable output the muxer also writes a Xing frame at the beginning, which
511 contains the number of frames in the file. It is useful for computing duration
514 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
515 are supplied to the muxer in form of a video stream with a single packet. There
516 can be any number of those streams, each will correspond to a single APIC frame.
517 The stream metadata tags @var{title} and @var{comment} map to APIC
518 @var{description} and @var{picture type} respectively. See
519 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
521 Note that the APIC frames must be written at the beginning, so the muxer will
522 buffer the audio frames until it gets all the pictures. It is therefore advised
523 to provide the pictures as soon as possible to avoid excessive buffering.
527 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
529 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
532 To attach a picture to an mp3 file select both the audio and the picture stream
535 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
536 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
541 MPEG transport stream muxer.
543 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
545 The muxer options are:
548 @item -mpegts_original_network_id @var{number}
549 Set the original_network_id (default 0x0001). This is unique identifier
550 of a network in DVB. Its main use is in the unique identification of a
551 service through the path Original_Network_ID, Transport_Stream_ID.
552 @item -mpegts_transport_stream_id @var{number}
553 Set the transport_stream_id (default 0x0001). This identifies a
555 @item -mpegts_service_id @var{number}
556 Set the service_id (default 0x0001) also known as program in DVB.
557 @item -mpegts_pmt_start_pid @var{number}
558 Set the first PID for PMT (default 0x1000, max 0x1f00).
559 @item -mpegts_start_pid @var{number}
560 Set the first PID for data packets (default 0x0100, max 0x0f00).
561 @item -mpegts_m2ts_mode @var{number}
562 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
563 @item -muxrate @var{number}
565 @item -pes_payload_size @var{number}
566 Set minimum PES packet payload in bytes.
567 @item -mpegts_flags @var{flags}
568 Set flags (see below).
569 @item -mpegts_copyts @var{number}
570 Preserve original timestamps, if value is set to 1. Default value is -1, which
571 results in shifting timestamps so that they start from 0.
572 @item -tables_version @var{number}
573 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
574 This option allows updating stream structure so that standard consumer may
575 detect the change. To do so, reopen output AVFormatContext (in case of API
576 usage) or restart ffmpeg instance, cyclically changing tables_version value:
578 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
579 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
581 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
582 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
583 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
588 Option mpegts_flags may take a set of such flags:
592 Reemit PAT/PMT before writing the next packet.
594 Use LATM packetization for AAC.
597 The recognized metadata settings in mpegts muxer are @code{service_provider}
598 and @code{service_name}. If they are not set the default for
599 @code{service_provider} is "FFmpeg" and the default for
600 @code{service_name} is "Service01".
603 ffmpeg -i file.mpg -c copy \
604 -mpegts_original_network_id 0x1122 \
605 -mpegts_transport_stream_id 0x3344 \
606 -mpegts_service_id 0x5566 \
607 -mpegts_pmt_start_pid 0x1500 \
608 -mpegts_start_pid 0x150 \
609 -metadata service_provider="Some provider" \
610 -metadata service_name="Some Channel" \
618 This muxer does not generate any output file, it is mainly useful for
619 testing or benchmarking purposes.
621 For example to benchmark decoding with @command{ffmpeg} you can use the
624 ffmpeg -benchmark -i INPUT -f null out.null
627 Note that the above command does not read or write the @file{out.null}
628 file, but specifying the output file is required by the @command{ffmpeg}
631 Alternatively you can write the command as:
633 ffmpeg -benchmark -i INPUT -f null -
641 @item -page_duration @var{duration}
642 Preferred page duration, in microseconds. The muxer will attempt to create
643 pages that are approximately @var{duration} microseconds long. This allows the
644 user to compromise between seek granularity and container overhead. The default
645 is 1 second. A value of 0 will fill all segments, making pages as large as
646 possible. A value of 1 will effectively use 1 packet-per-page in most
647 situations, giving a small seek granularity at the cost of additional container
651 @section segment, stream_segment, ssegment
653 Basic stream segmenter.
655 The segmenter muxer outputs streams to a number of separate files of nearly
656 fixed duration. Output filename pattern can be set in a fashion similar to
659 @code{stream_segment} is a variant of the muxer used to write to
660 streaming output formats, i.e. which do not require global headers,
661 and is recommended for outputting e.g. to MPEG transport stream segments.
662 @code{ssegment} is a shorter alias for @code{stream_segment}.
664 Every segment starts with a keyframe of the selected reference stream,
665 which is set through the @option{reference_stream} option.
667 Note that if you want accurate splitting for a video file, you need to
668 make the input key frames correspond to the exact splitting times
669 expected by the segmenter, or the segment muxer will start the new
670 segment with the key frame found next after the specified start
673 The segment muxer works best with a single constant frame rate video.
675 Optionally it can generate a list of the created segments, by setting
676 the option @var{segment_list}. The list type is specified by the
677 @var{segment_list_type} option. The entry filenames in the segment
678 list are set by default to the basename of the corresponding segment
681 The segment muxer supports the following options:
684 @item reference_stream @var{specifier}
685 Set the reference stream, as specified by the string @var{specifier}.
686 If @var{specifier} is set to @code{auto}, the reference is choosen
687 automatically. Otherwise it must be a stream specifier (see the ``Stream
688 specifiers'' chapter in the ffmpeg manual) which specifies the
689 reference stream. The default value is @code{auto}.
691 @item segment_format @var{format}
692 Override the inner container format, by default it is guessed by the filename
695 @item segment_list @var{name}
696 Generate also a listfile named @var{name}. If not specified no
697 listfile is generated.
699 @item segment_list_flags @var{flags}
700 Set flags affecting the segment list generation.
702 It currently supports the following flags:
705 Allow caching (only affects M3U8 list files).
708 Allow live-friendly file generation.
711 @item segment_list_size @var{size}
712 Update the list file so that it contains at most the last @var{size}
713 segments. If 0 the list file will contain all the segments. Default
716 @item segment_list_entry_prefix @var{prefix}
717 Set @var{prefix} to prepend to the name of each entry filename. By
718 default no prefix is applied.
720 @item segment_list_type @var{type}
721 Specify the format for the segment list file.
723 The following values are recognized:
726 Generate a flat list for the created segments, one segment per line.
729 Generate a list for the created segments, one segment per line,
730 each line matching the format (comma-separated values):
732 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
735 @var{segment_filename} is the name of the output file generated by the
736 muxer according to the provided pattern. CSV escaping (according to
737 RFC4180) is applied if required.
739 @var{segment_start_time} and @var{segment_end_time} specify
740 the segment start and end time expressed in seconds.
742 A list file with the suffix @code{".csv"} or @code{".ext"} will
743 auto-select this format.
745 @samp{ext} is deprecated in favor or @samp{csv}.
748 Generate an ffconcat file for the created segments. The resulting file
749 can be read using the FFmpeg @ref{concat} demuxer.
751 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
752 auto-select this format.
755 Generate an extended M3U8 file, version 3, compliant with
756 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
758 A list file with the suffix @code{".m3u8"} will auto-select this format.
761 If not specified the type is guessed from the list file name suffix.
763 @item segment_time @var{time}
764 Set segment duration to @var{time}, the value must be a duration
765 specification. Default value is "2". See also the
766 @option{segment_times} option.
768 Note that splitting may not be accurate, unless you force the
769 reference stream key-frames at the given time. See the introductory
770 notice and the examples below.
772 @item segment_time_delta @var{delta}
773 Specify the accuracy time when selecting the start time for a
774 segment, expressed as a duration specification. Default value is "0".
776 When delta is specified a key-frame will start a new segment if its
777 PTS satisfies the relation:
779 PTS >= start_time - time_delta
782 This option is useful when splitting video content, which is always
783 split at GOP boundaries, in case a key frame is found just before the
784 specified split time.
786 In particular may be used in combination with the @file{ffmpeg} option
787 @var{force_key_frames}. The key frame times specified by
788 @var{force_key_frames} may not be set accurately because of rounding
789 issues, with the consequence that a key frame time may result set just
790 before the specified time. For constant frame rate videos a value of
791 1/2*@var{frame_rate} should address the worst case mismatch between
792 the specified time and the time set by @var{force_key_frames}.
794 @item segment_times @var{times}
795 Specify a list of split points. @var{times} contains a list of comma
796 separated duration specifications, in increasing order. See also
797 the @option{segment_time} option.
799 @item segment_frames @var{frames}
800 Specify a list of split video frame numbers. @var{frames} contains a
801 list of comma separated integer numbers, in increasing order.
803 This option specifies to start a new segment whenever a reference
804 stream key frame is found and the sequential number (starting from 0)
805 of the frame is greater or equal to the next value in the list.
807 @item segment_wrap @var{limit}
808 Wrap around segment index once it reaches @var{limit}.
810 @item segment_start_number @var{number}
811 Set the sequence number of the first segment. Defaults to @code{0}.
813 @item reset_timestamps @var{1|0}
814 Reset timestamps at the begin of each segment, so that each segment
815 will start with near-zero timestamps. It is meant to ease the playback
816 of the generated segments. May not work with some combinations of
817 muxers/codecs. It is set to @code{0} by default.
819 @item initial_offset @var{offset}
820 Specify timestamp offset to apply to the output packet timestamps. The
821 argument must be a time duration specification, and defaults to 0.
828 To remux the content of file @file{in.mkv} to a list of segments
829 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
830 generated segments to @file{out.list}:
832 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
836 As the example above, but segment the input file according to the split
837 points specified by the @var{segment_times} option:
839 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
843 As the example above, but use the @command{ffmpeg} @option{force_key_frames}
844 option to force key frames in the input at the specified location, together
845 with the segment option @option{segment_time_delta} to account for
846 possible roundings operated when setting key frame times.
848 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
849 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
851 In order to force key frames on the input file, transcoding is
855 Segment the input file by splitting the input file according to the
856 frame numbers sequence specified with the @option{segment_frames} option:
858 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
862 To convert the @file{in.mkv} to TS segments using the @code{libx264}
863 and @code{libfaac} encoders:
865 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
869 Segment the input file, and create an M3U8 live playlist (can be used
872 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
873 -segment_list_flags +live -segment_time 10 out%03d.mkv
879 The tee muxer can be used to write the same data to several files or any
880 other kind of muxer. It can be used, for example, to both stream a video to
881 the network and save it to disk at the same time.
883 It is different from specifying several outputs to the @command{ffmpeg}
884 command-line tool because the audio and video data will be encoded only once
885 with the tee muxer; encoding can be a very expensive process. It is not
886 useful when using the libavformat API directly because it is then possible
887 to feed the same packets to several muxers directly.
889 The slave outputs are specified in the file name given to the muxer,
890 separated by '|'. If any of the slave name contains the '|' separator,
891 leading or trailing spaces or any special character, it must be
892 escaped (see the ``Quoting and escaping'' section in the ffmpeg-utils
895 Muxer options can be specified for each slave by prepending them as a list of
896 @var{key}=@var{value} pairs separated by ':', between square brackets. If
897 the options values contain a special character or the ':' separator, they
898 must be escaped; note that this is a second level escaping.
900 The following special options are also recognized:
903 Specify the format name. Useful if it cannot be guessed from the
906 @item bsfs[/@var{spec}]
907 Specify a list of bitstream filters to apply to the specified
908 output. It is possible to specify to which streams a given bitstream
909 filter applies, by appending a stream specifier to the option
910 separated by @code{/}. If the stream specifier is not specified, the
911 bistream filters will be applied to all streams in the output.
913 Several bitstream filters can be specified, separated by ",".
916 Select the streams that should be mapped to the slave output,
917 specified by a stream specifier. If not specified, this defaults to
918 all the input streams.
921 Some examples follow.
924 Encode something and both archive it in a WebM file and stream it
925 as MPEG-TS over UDP (the streams need to be explicitly mapped):
927 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
928 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
932 Use @command{ffmpeg} to encode the input, and send the output
933 to three different destinations. The @code{dump_extra} bitstream
934 filter is used to add extradata information to all the output video
935 keyframes packets, as requested by the MPEG-TS format. The select
936 option is applied to @file{out.aac} in order to make it contain only
939 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
940 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
944 Note: some codecs may need different options depending on the output format;
945 the auto-detection of this can not work with the tee muxer. The main example
946 is the @option{global_header} flag.