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.
28 It accepts the following options:
32 Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).
35 Select ID3v2 version to write. Currently only version 3 and 4 (aka.
36 ID3v2.3 and ID3v2.4) are supported. The default is version 4.
43 CRC (Cyclic Redundancy Check) testing format.
45 This muxer computes and prints the Adler-32 CRC of all the input audio
46 and video frames. By default audio frames are converted to signed
47 16-bit raw audio and video frames to raw video before computing the
50 The output of the muxer consists of a single line of the form:
51 CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
52 8 digits containing the CRC for all the decoded input frames.
54 See also the @ref{framecrc} muxer.
58 For example to compute the CRC of the input, and store it in the file
61 ffmpeg -i INPUT -f crc out.crc
64 You can print the CRC to stdout with the command:
66 ffmpeg -i INPUT -f crc -
69 You can select the output format of each frame with @command{ffmpeg} by
70 specifying the audio and video codec and format. For example to
71 compute the CRC of the input audio converted to PCM unsigned 8-bit
72 and the input video converted to MPEG-2 video, use the command:
74 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
80 Per-packet CRC (Cyclic Redundancy Check) testing format.
82 This muxer computes and prints the Adler-32 CRC for each audio
83 and video packet. By default audio frames are converted to signed
84 16-bit raw audio and video frames to raw video before computing the
87 The output of the muxer consists of a line for each audio and video
90 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
93 @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
98 For example to compute the CRC of the audio and video frames in
99 @file{INPUT}, converted to raw audio and video packets, and store it
100 in the file @file{out.crc}:
102 ffmpeg -i INPUT -f framecrc out.crc
105 To print the information to stdout, use the command:
107 ffmpeg -i INPUT -f framecrc -
110 With @command{ffmpeg}, you can select the output format to which the
111 audio and video frames are encoded before computing the CRC for each
112 packet by specifying the audio and video codec. For example, to
113 compute the CRC of each decoded input audio frame converted to PCM
114 unsigned 8-bit and of each decoded input video frame converted to
115 MPEG-2 video, use the command:
117 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
120 See also the @ref{crc} muxer.
125 Per-packet MD5 testing format.
127 This muxer computes and prints the MD5 hash for each audio
128 and video packet. By default audio frames are converted to signed
129 16-bit raw audio and video frames to raw video before computing the
132 The output of the muxer consists of a line for each audio and video
135 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
138 @var{MD5} is a hexadecimal number representing the computed MD5 hash
143 For example to compute the MD5 of the audio and video frames in
144 @file{INPUT}, converted to raw audio and video packets, and store it
145 in the file @file{out.md5}:
147 ffmpeg -i INPUT -f framemd5 out.md5
150 To print the information to stdout, use the command:
152 ffmpeg -i INPUT -f framemd5 -
155 See also the @ref{md5} muxer.
162 It accepts the following options:
166 Set the number of times to loop the output. Use @code{-1} for no loop, @code{0}
167 for looping indefinitely (default).
170 Force the delay (expressed in centiseconds) after the last frame. Each frame
171 ends with a delay until the next frame. The default is @code{-1}, which is a
172 special value to tell the muxer to re-use the previous delay. In case of a
173 loop, you might want to customize this value to mark a pause for instance.
176 For example, to encode a gif looping 10 times, with a 5 seconds delay between
179 ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif
182 Note 1: if you wish to extract the frames in separate GIF files, you need to
183 force the @ref{image2} muxer:
185 ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"
188 Note 2: the GIF format has a very small time base: the delay between two frames
189 can not be smaller than one centi second.
194 Apple HTTP Live Streaming muxer that segments MPEG-TS according to
195 the HTTP Live Streaming (HLS) specification.
197 It creates a playlist file, and one or more segment files. The output filename
198 specifies the playlist filename.
200 By default, the muxer creates a file for each segment produced. These files
201 have the same name as the playlist, followed by a sequential number and a
204 For example, to convert an input file with @command{ffmpeg}:
206 ffmpeg -i in.nut out.m3u8
208 This example will produce the playlist, @file{out.m3u8}, and segment files:
209 @file{out0.ts}, @file{out1.ts}, @file{out2.ts}, etc.
211 See also the @ref{segment} muxer, which provides a more generic and
212 flexible implementation of a segmenter, and can be used to perform HLS
217 This muxer supports the following options:
220 @item hls_time @var{seconds}
221 Set the segment length in seconds. Default value is 2.
223 @item hls_list_size @var{size}
224 Set the maximum number of playlist entries. If set to 0 the list file
225 will contain all the segments. Default value is 5.
227 @item hls_ts_options @var{options_list}
228 Set output format options using a :-separated list of key=value
229 parameters. Values containing @code{:} special characters must be
232 @item hls_wrap @var{wrap}
233 Set the number after which the segment filename number (the number
234 specified in each segment file) wraps. If set to 0 the number will be
235 never wrapped. Default value is 0.
237 This option is useful to avoid to fill the disk with many segment
238 files, and limits the maximum number of segment files written to disk
241 @item start_number @var{number}
242 Start the playlist sequence number from @var{number}. Default value is
245 @item hls_allow_cache @var{allowcache}
246 Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments.
248 @item hls_base_url @var{baseurl}
249 Append @var{baseurl} to every entry in the playlist.
250 Useful to generate playlists with absolute paths.
252 Note that the playlist sequence number must be unique for each segment
253 and it is not to be confused with the segment filename sequence number
254 which can be cyclic, for example if the @option{wrap} option is
257 @item hls_flags single_file
258 If this flag is set, the muxer will store all segments in a single MPEG-TS
259 file, and will use byte ranges in the playlist. HLS playlists generated with
260 this way will have the version number 4.
263 ffmpeg -i in.nut -hls_flags single_file out.m3u8
265 Will produce the playlist, @file{out.m3u8}, and a single segment file,
274 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
278 Size cannot exceed 256 pixels in any dimension
281 Only BMP and PNG images can be stored
284 If a BMP image is used, it must be one of the following pixel formats:
286 BMP Bit Depth FFmpeg Pixel Format
296 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
299 If a PNG image is used, it must use the rgba pixel format
307 The image file muxer writes video frames to image files.
309 The output filenames are specified by a pattern, which can be used to
310 produce sequentially numbered series of files.
311 The pattern may contain the string "%d" or "%0@var{N}d", this string
312 specifies the position of the characters representing a numbering in
313 the filenames. If the form "%0@var{N}d" is used, the string
314 representing the number in each filename is 0-padded to @var{N}
315 digits. The literal character '%' can be specified in the pattern with
318 If the pattern contains "%d" or "%0@var{N}d", the first filename of
319 the file list specified will contain the number 1, all the following
320 numbers will be sequential.
322 The pattern may contain a suffix which is used to automatically
323 determine the format of the image files to write.
325 For example the pattern "img-%03d.bmp" will specify a sequence of
326 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
327 @file{img-010.bmp}, etc.
328 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
329 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
334 The following example shows how to use @command{ffmpeg} for creating a
335 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
336 taking one image every second from the input video:
338 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
341 Note that with @command{ffmpeg}, if the format is not specified with the
342 @code{-f} option and the output filename specifies an image file
343 format, the image2 muxer is automatically selected, so the previous
344 command can be written as:
346 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
349 Note also that the pattern must not necessarily contain "%d" or
350 "%0@var{N}d", for example to create a single image file
351 @file{img.jpeg} from the input video you can employ the command:
353 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
356 The @option{strftime} option allows you to expand the filename with
357 date and time information. Check the documentation of
358 the @code{strftime()} function for the syntax.
360 For example to generate image files from the @code{strftime()}
361 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
364 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
371 Start the sequence from the specified number. Default value is 1. Must
372 be a non-negative number.
375 If set to 1, the filename will always be interpreted as just a
376 filename, not a pattern, and the corresponding file will be continuously
377 overwritten with new images. Default value is 0.
380 If set to 1, expand the filename with date and time information from
381 @code{strftime()}. Default value is 0.
384 The image muxer supports the .Y.U.V image file format. This format is
385 special in that that each image frame consists of three files, for
386 each of the YUV420P components. To read or write this image file format,
387 specify the name of the '.Y' file. The muxer will automatically open the
388 '.U' and '.V' files as required.
392 Matroska container muxer.
394 This muxer implements the matroska and webm container specs.
398 The recognized metadata settings in this muxer are:
402 Set title name provided to a single track.
405 Specify the language of the track in the Matroska languages form.
407 The language can be either the 3 letters bibliographic ISO-639-2 (ISO
408 639-2/B) form (like "fre" for French), or a language code mixed with a
409 country code for specialities in languages (like "fre-ca" for Canadian
413 Set stereo 3D video layout of two views in a single video track.
415 The following values are recognized:
420 Both views are arranged side by side, Left-eye view is on the left
422 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
424 Both views are arranged in top-bottom orientation, Left-eye view is on top
425 @item checkerboard_rl
426 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
427 @item checkerboard_lr
428 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
429 @item row_interleaved_rl
430 Each view is constituted by a row based interleaving, Right-eye view is first row
431 @item row_interleaved_lr
432 Each view is constituted by a row based interleaving, Left-eye view is first row
433 @item col_interleaved_rl
434 Both views are arranged in a column based interleaving manner, Right-eye view is first column
435 @item col_interleaved_lr
436 Both views are arranged in a column based interleaving manner, Left-eye view is first column
437 @item anaglyph_cyan_red
438 All frames are in anaglyph format viewable through red-cyan filters
440 Both views are arranged side by side, Right-eye view is on the left
441 @item anaglyph_green_magenta
442 All frames are in anaglyph format viewable through green-magenta filters
444 Both eyes laced in one Block, Left-eye view is first
446 Both eyes laced in one Block, Right-eye view is first
450 For example a 3D WebM clip can be created using the following command line:
452 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
457 This muxer supports the following options:
460 @item reserve_index_space
461 By default, this muxer writes the index for seeking (called cues in Matroska
462 terms) at the end of the file, because it cannot know in advance how much space
463 to leave for the index at the beginning of the file. However for some use cases
464 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
465 index at the beginning of the file.
467 If this option is set to a non-zero value, the muxer will reserve a given amount
468 of space in the file header and then try to write the cues there when the muxing
469 finishes. If the available space does not suffice, muxing will fail. A safe size
470 for most use cases should be about 50kB per hour of video.
472 Note that cues are only written if the output is seekable and this option will
473 have no effect if it is not.
481 This muxer computes and prints the MD5 hash of all the input audio
482 and video frames. By default audio frames are converted to signed
483 16-bit raw audio and video frames to raw video before computing the
486 The output of the muxer consists of a single line of the form:
487 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
488 the computed MD5 hash.
490 For example to compute the MD5 hash of the input converted to raw
491 audio and video, and store it in the file @file{out.md5}:
493 ffmpeg -i INPUT -f md5 out.md5
496 You can print the MD5 to stdout with the command:
498 ffmpeg -i INPUT -f md5 -
501 See also the @ref{framemd5} muxer.
503 @section mov, mp4, ismv
505 MOV/MP4/ISMV (Smooth Streaming) muxer.
507 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
508 file has all the metadata about all packets stored in one location
509 (written at the end of the file, it can be moved to the start for
510 better playback by adding @var{faststart} to the @var{movflags}, or
511 using the @command{qt-faststart} tool). A fragmented
512 file consists of a number of fragments, where packets and metadata
513 about these packets are stored together. Writing a fragmented
514 file has the advantage that the file is decodable even if the
515 writing is interrupted (while a normal MOV/MP4 is undecodable if
516 it is not properly finished), and it requires less memory when writing
517 very long files (since writing normal MOV/MP4 files stores info about
518 every single packet in memory until the file is closed). The downside
519 is that it is less compatible with other applications.
523 Fragmentation is enabled by setting one of the AVOptions that define
524 how to cut the file into fragments:
527 @item -moov_size @var{bytes}
528 Reserves space for the moov atom at the beginning of the file instead of placing the
529 moov atom at the end. If the space reserved is insufficient, muxing will fail.
530 @item -movflags frag_keyframe
531 Start a new fragment at each video keyframe.
532 @item -frag_duration @var{duration}
533 Create fragments that are @var{duration} microseconds long.
534 @item -frag_size @var{size}
535 Create fragments that contain up to @var{size} bytes of payload data.
536 @item -movflags frag_custom
537 Allow the caller to manually choose when to cut fragments, by
538 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
539 the packets written so far. (This is only useful with other
540 applications integrating libavformat, not from @command{ffmpeg}.)
541 @item -min_frag_duration @var{duration}
542 Don't create fragments that are shorter than @var{duration} microseconds long.
545 If more than one condition is specified, fragments are cut when
546 one of the specified conditions is fulfilled. The exception to this is
547 @code{-min_frag_duration}, which has to be fulfilled for any of the other
550 Additionally, the way the output file is written can be adjusted
551 through a few other options:
554 @item -movflags empty_moov
555 Write an initial moov atom directly at the start of the file, without
556 describing any samples in it. Generally, an mdat/moov pair is written
557 at the start of the file, as a normal MOV/MP4 file, containing only
558 a short portion of the file. With this option set, there is no initial
559 mdat atom, and the moov atom only describes the tracks but has
562 This option is implicitly set when writing ismv (Smooth Streaming) files.
563 @item -movflags separate_moof
564 Write a separate moof (movie fragment) atom for each track. Normally,
565 packets for all tracks are written in a moof atom (which is slightly
566 more efficient), but with this option set, the muxer writes one moof/mdat
567 pair for each track, making it easier to separate tracks.
569 This option is implicitly set when writing ismv (Smooth Streaming) files.
570 @item -movflags faststart
571 Run a second pass moving the index (moov atom) to the beginning of the file.
572 This operation can take a while, and will not work in various situations such
573 as fragmented output, thus it is not enabled by default.
574 @item -movflags rtphint
575 Add RTP hinting tracks to the output file.
576 @item -movflags disable_chpl
577 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
578 and a QuickTime chapter track are written to the file. With this option
579 set, only the QuickTime chapter track will be written. Nero chapters can
580 cause failures when the file is reprocessed with certain tagging programs, like
581 mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
582 @item -movflags omit_tfhd_offset
583 Do not write any absolute base_data_offset in tfhd atoms. This avoids
584 tying fragments to absolute byte positions in the file/streams.
585 @item -movflags default_base_moof
586 Similarly to the omit_tfhd_offset, this flag avoids writing the
587 absolute base_data_offset field in tfhd atoms, but does so by using
588 the new default-base-is-moof flag instead. This flag is new from
589 14496-12:2012. This may make the fragments easier to parse in certain
590 circumstances (avoiding basing track fragment location calculations
591 on the implicit end of the previous track fragment).
596 Smooth Streaming content can be pushed in real time to a publishing
597 point on IIS with this muxer. Example:
599 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
604 The MP3 muxer writes a raw MP3 stream with the following optional features:
607 An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
608 2.4 are supported, the @code{id3v2_version} private option controls which one is
609 used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header
612 The muxer supports writing attached pictures (APIC frames) to the ID3v2 header.
613 The pictures are supplied to the muxer in form of a video stream with a single
614 packet. There can be any number of those streams, each will correspond to a
615 single APIC frame. The stream metadata tags @var{title} and @var{comment} map
616 to APIC @var{description} and @var{picture type} respectively. See
617 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
619 Note that the APIC frames must be written at the beginning, so the muxer will
620 buffer the audio frames until it gets all the pictures. It is therefore advised
621 to provide the pictures as soon as possible to avoid excessive buffering.
624 A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
625 default, but will be written only if the output is seekable. The
626 @code{write_xing} private option can be used to disable it. The frame contains
627 various information that may be useful to the decoder, like the audio duration
631 A legacy ID3v1 tag at the end of the file (disabled by default). It may be
632 enabled with the @code{write_id3v1} private option, but as its capabilities are
633 very limited, its usage is not recommended.
638 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
640 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
643 To attach a picture to an mp3 file select both the audio and the picture stream
646 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
647 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
650 Write a "clean" MP3 without any extra features:
652 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
657 MPEG transport stream muxer.
659 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
661 The recognized metadata settings in mpegts muxer are @code{service_provider}
662 and @code{service_name}. If they are not set the default for
663 @code{service_provider} is "FFmpeg" and the default for
664 @code{service_name} is "Service01".
668 The muxer options are:
671 @item -mpegts_original_network_id @var{number}
672 Set the original_network_id (default 0x0001). This is unique identifier
673 of a network in DVB. Its main use is in the unique identification of a
674 service through the path Original_Network_ID, Transport_Stream_ID.
675 @item -mpegts_transport_stream_id @var{number}
676 Set the transport_stream_id (default 0x0001). This identifies a
678 @item -mpegts_service_id @var{number}
679 Set the service_id (default 0x0001) also known as program in DVB.
680 @item -mpegts_pmt_start_pid @var{number}
681 Set the first PID for PMT (default 0x1000, max 0x1f00).
682 @item -mpegts_start_pid @var{number}
683 Set the first PID for data packets (default 0x0100, max 0x0f00).
684 @item -mpegts_m2ts_mode @var{number}
685 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
686 @item -muxrate @var{number}
687 Set a constant muxrate (default VBR).
688 @item -pcr_period @var{numer}
689 Override the default PCR retransmission time (default 20ms), ignored
690 if variable muxrate is selected.
691 @item -pes_payload_size @var{number}
692 Set minimum PES packet payload in bytes.
693 @item -mpegts_flags @var{flags}
694 Set flags (see below).
695 @item -mpegts_copyts @var{number}
696 Preserve original timestamps, if value is set to 1. Default value is -1, which
697 results in shifting timestamps so that they start from 0.
698 @item -tables_version @var{number}
699 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
700 This option allows updating stream structure so that standard consumer may
701 detect the change. To do so, reopen output AVFormatContext (in case of API
702 usage) or restart ffmpeg instance, cyclically changing tables_version value:
704 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
705 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
707 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
708 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
709 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
714 Option mpegts_flags may take a set of such flags:
718 Reemit PAT/PMT before writing the next packet.
720 Use LATM packetization for AAC.
726 ffmpeg -i file.mpg -c copy \
727 -mpegts_original_network_id 0x1122 \
728 -mpegts_transport_stream_id 0x3344 \
729 -mpegts_service_id 0x5566 \
730 -mpegts_pmt_start_pid 0x1500 \
731 -mpegts_start_pid 0x150 \
732 -metadata service_provider="Some provider" \
733 -metadata service_name="Some Channel" \
741 This muxer does not generate any output file, it is mainly useful for
742 testing or benchmarking purposes.
744 For example to benchmark decoding with @command{ffmpeg} you can use the
747 ffmpeg -benchmark -i INPUT -f null out.null
750 Note that the above command does not read or write the @file{out.null}
751 file, but specifying the output file is required by the @command{ffmpeg}
754 Alternatively you can write the command as:
756 ffmpeg -benchmark -i INPUT -f null -
762 @item -syncpoints @var{flags}
763 Change the syncpoint usage in nut:
765 @item @var{default} use the normal low-overhead seeking aids.
766 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
767 Use of this option is not recommended, as the resulting files are very damage
768 sensitive and seeking is not possible. Also in general the overhead from
769 syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
770 all growing data tables, allowing to mux endless streams with limited memory
771 and wihout these disadvantages.
772 @item @var{timestamped} extend the syncpoint with a wallclock field.
774 The @var{none} and @var{timestamped} flags are experimental.
775 @item -write_index @var{bool}
776 Write index at the end, the default is to write an index.
780 ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
788 @item -page_duration @var{duration}
789 Preferred page duration, in microseconds. The muxer will attempt to create
790 pages that are approximately @var{duration} microseconds long. This allows the
791 user to compromise between seek granularity and container overhead. The default
792 is 1 second. A value of 0 will fill all segments, making pages as large as
793 possible. A value of 1 will effectively use 1 packet-per-page in most
794 situations, giving a small seek granularity at the cost of additional container
799 @section segment, stream_segment, ssegment
801 Basic stream segmenter.
803 This muxer outputs streams to a number of separate files of nearly
804 fixed duration. Output filename pattern can be set in a fashion similar to
807 @code{stream_segment} is a variant of the muxer used to write to
808 streaming output formats, i.e. which do not require global headers,
809 and is recommended for outputting e.g. to MPEG transport stream segments.
810 @code{ssegment} is a shorter alias for @code{stream_segment}.
812 Every segment starts with a keyframe of the selected reference stream,
813 which is set through the @option{reference_stream} option.
815 Note that if you want accurate splitting for a video file, you need to
816 make the input key frames correspond to the exact splitting times
817 expected by the segmenter, or the segment muxer will start the new
818 segment with the key frame found next after the specified start
821 The segment muxer works best with a single constant frame rate video.
823 Optionally it can generate a list of the created segments, by setting
824 the option @var{segment_list}. The list type is specified by the
825 @var{segment_list_type} option. The entry filenames in the segment
826 list are set by default to the basename of the corresponding segment
829 See also the @ref{hls} muxer, which provides a more specific
830 implementation for HLS segmentation.
834 The segment muxer supports the following options:
837 @item reference_stream @var{specifier}
838 Set the reference stream, as specified by the string @var{specifier}.
839 If @var{specifier} is set to @code{auto}, the reference is chosen
840 automatically. Otherwise it must be a stream specifier (see the ``Stream
841 specifiers'' chapter in the ffmpeg manual) which specifies the
842 reference stream. The default value is @code{auto}.
844 @item segment_format @var{format}
845 Override the inner container format, by default it is guessed by the filename
848 @item segment_format_options @var{options_list}
849 Set output format options using a :-separated list of key=value
850 parameters. Values containing the @code{:} special character must be
853 @item segment_list @var{name}
854 Generate also a listfile named @var{name}. If not specified no
855 listfile is generated.
857 @item segment_list_flags @var{flags}
858 Set flags affecting the segment list generation.
860 It currently supports the following flags:
863 Allow caching (only affects M3U8 list files).
866 Allow live-friendly file generation.
869 @item segment_list_type @var{type}
870 Select the listing format.
872 @item @var{flat} use a simple flat list of entries.
873 @item @var{hls} use a m3u8-like structure.
876 @item segment_list_size @var{size}
877 Update the list file so that it contains at most @var{size}
878 segments. If 0 the list file will contain all the segments. Default
881 @item segment_list_entry_prefix @var{prefix}
882 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
883 By default no prefix is applied.
885 The following values are recognized:
888 Generate a flat list for the created segments, one segment per line.
891 Generate a list for the created segments, one segment per line,
892 each line matching the format (comma-separated values):
894 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
897 @var{segment_filename} is the name of the output file generated by the
898 muxer according to the provided pattern. CSV escaping (according to
899 RFC4180) is applied if required.
901 @var{segment_start_time} and @var{segment_end_time} specify
902 the segment start and end time expressed in seconds.
904 A list file with the suffix @code{".csv"} or @code{".ext"} will
905 auto-select this format.
907 @samp{ext} is deprecated in favor or @samp{csv}.
910 Generate an ffconcat file for the created segments. The resulting file
911 can be read using the FFmpeg @ref{concat} demuxer.
913 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
914 auto-select this format.
917 Generate an extended M3U8 file, version 3, compliant with
918 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
920 A list file with the suffix @code{".m3u8"} will auto-select this format.
923 If not specified the type is guessed from the list file name suffix.
925 @item segment_time @var{time}
926 Set segment duration to @var{time}, the value must be a duration
927 specification. Default value is "2". See also the
928 @option{segment_times} option.
930 Note that splitting may not be accurate, unless you force the
931 reference stream key-frames at the given time. See the introductory
932 notice and the examples below.
934 @item segment_atclocktime @var{1|0}
935 If set to "1" split at regular clock time intervals starting from 00:00
936 o'clock. The @var{time} value specified in @option{segment_time} is
937 used for setting the length of the splitting interval.
939 For example with @option{segment_time} set to "900" this makes it possible
940 to create files at 12:00 o'clock, 12:15, 12:30, etc.
942 Default value is "0".
944 @item segment_time_delta @var{delta}
945 Specify the accuracy time when selecting the start time for a
946 segment, expressed as a duration specification. Default value is "0".
948 When delta is specified a key-frame will start a new segment if its
949 PTS satisfies the relation:
951 PTS >= start_time - time_delta
954 This option is useful when splitting video content, which is always
955 split at GOP boundaries, in case a key frame is found just before the
956 specified split time.
958 In particular may be used in combination with the @file{ffmpeg} option
959 @var{force_key_frames}. The key frame times specified by
960 @var{force_key_frames} may not be set accurately because of rounding
961 issues, with the consequence that a key frame time may result set just
962 before the specified time. For constant frame rate videos a value of
963 1/(2*@var{frame_rate}) should address the worst case mismatch between
964 the specified time and the time set by @var{force_key_frames}.
966 @item segment_times @var{times}
967 Specify a list of split points. @var{times} contains a list of comma
968 separated duration specifications, in increasing order. See also
969 the @option{segment_time} option.
971 @item segment_frames @var{frames}
972 Specify a list of split video frame numbers. @var{frames} contains a
973 list of comma separated integer numbers, in increasing order.
975 This option specifies to start a new segment whenever a reference
976 stream key frame is found and the sequential number (starting from 0)
977 of the frame is greater or equal to the next value in the list.
979 @item segment_wrap @var{limit}
980 Wrap around segment index once it reaches @var{limit}.
982 @item segment_start_number @var{number}
983 Set the sequence number of the first segment. Defaults to @code{0}.
985 @item reset_timestamps @var{1|0}
986 Reset timestamps at the begin of each segment, so that each segment
987 will start with near-zero timestamps. It is meant to ease the playback
988 of the generated segments. May not work with some combinations of
989 muxers/codecs. It is set to @code{0} by default.
991 @item initial_offset @var{offset}
992 Specify timestamp offset to apply to the output packet timestamps. The
993 argument must be a time duration specification, and defaults to 0.
1000 Remux the content of file @file{in.mkv} to a list of segments
1001 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
1002 generated segments to @file{out.list}:
1004 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
1008 Segment input and set output format options for the output segments:
1010 ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
1014 Segment the input file according to the split points specified by the
1015 @var{segment_times} option:
1017 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
1021 Use the @command{ffmpeg} @option{force_key_frames}
1022 option to force key frames in the input at the specified location, together
1023 with the segment option @option{segment_time_delta} to account for
1024 possible roundings operated when setting key frame times.
1026 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
1027 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
1029 In order to force key frames on the input file, transcoding is
1033 Segment the input file by splitting the input file according to the
1034 frame numbers sequence specified with the @option{segment_frames} option:
1036 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
1040 Convert the @file{in.mkv} to TS segments using the @code{libx264}
1041 and @code{libfaac} encoders:
1043 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
1047 Segment the input file, and create an M3U8 live playlist (can be used
1048 as live HLS source):
1050 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
1051 -segment_list_flags +live -segment_time 10 out%03d.mkv
1055 @section smoothstreaming
1057 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
1061 Specify the number of fragments kept in the manifest. Default 0 (keep all).
1063 @item extra_window_size
1064 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
1066 @item lookahead_count
1067 Specify the number of lookahead fragments. Default 2.
1069 @item min_frag_duration
1070 Specify the minimum fragment duration (in microseconds). Default 5000000.
1072 @item remove_at_exit
1073 Specify whether to remove all fragments when finished. Default 0 (do not remove).
1079 The tee muxer can be used to write the same data to several files or any
1080 other kind of muxer. It can be used, for example, to both stream a video to
1081 the network and save it to disk at the same time.
1083 It is different from specifying several outputs to the @command{ffmpeg}
1084 command-line tool because the audio and video data will be encoded only once
1085 with the tee muxer; encoding can be a very expensive process. It is not
1086 useful when using the libavformat API directly because it is then possible
1087 to feed the same packets to several muxers directly.
1089 The slave outputs are specified in the file name given to the muxer,
1090 separated by '|'. If any of the slave name contains the '|' separator,
1091 leading or trailing spaces or any special character, it must be
1092 escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
1093 section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
1095 Muxer options can be specified for each slave by prepending them as a list of
1096 @var{key}=@var{value} pairs separated by ':', between square brackets. If
1097 the options values contain a special character or the ':' separator, they
1098 must be escaped; note that this is a second level escaping.
1100 The following special options are also recognized:
1103 Specify the format name. Useful if it cannot be guessed from the
1106 @item bsfs[/@var{spec}]
1107 Specify a list of bitstream filters to apply to the specified
1110 It is possible to specify to which streams a given bitstream filter
1111 applies, by appending a stream specifier to the option separated by
1112 @code{/}. @var{spec} must be a stream specifier (see @ref{Format
1113 stream specifiers}). If the stream specifier is not specified, the
1114 bitstream filters will be applied to all streams in the output.
1116 Several bitstream filters can be specified, separated by ",".
1119 Select the streams that should be mapped to the slave output,
1120 specified by a stream specifier. If not specified, this defaults to
1121 all the input streams.
1124 @subsection Examples
1128 Encode something and both archive it in a WebM file and stream it
1129 as MPEG-TS over UDP (the streams need to be explicitly mapped):
1131 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
1132 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
1136 Use @command{ffmpeg} to encode the input, and send the output
1137 to three different destinations. The @code{dump_extra} bitstream
1138 filter is used to add extradata information to all the output video
1139 keyframes packets, as requested by the MPEG-TS format. The select
1140 option is applied to @file{out.aac} in order to make it contain only
1143 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1144 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
1148 As below, but select only stream @code{a:1} for the audio output. Note
1149 that a second level escaping must be performed, as ":" is a special
1150 character used to separate options.
1152 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1153 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
1157 Note: some codecs may need different options depending on the output format;
1158 the auto-detection of this can not work with the tee muxer. The main example
1159 is the @option{global_header} flag.
1161 @section webm_dash_manifest
1163 WebM DASH Manifest muxer.
1165 This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
1169 This muxer supports the following options:
1172 @item adaptation_sets
1173 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
1174 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
1175 audio and video streams. Any number of adaptation sets can be added using this option.
1180 ffmpeg -f webm_dash_manifest -i video1.webm \
1181 -f webm_dash_manifest -i video2.webm \
1182 -f webm_dash_manifest -i audio1.webm \
1183 -f webm_dash_manifest -i audio2.webm \
1184 -map 0 -map 1 -map 2 -map 3 \
1186 -f webm_dash_manifest \
1187 -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \