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_base_url @var{baseurl}
246 Append @var{baseurl} to every entry in the playlist.
247 Useful to generate playlists with absolute paths.
249 Note that the playlist sequence number must be unique for each segment
250 and it is not to be confused with the segment filename sequence number
251 which can be cyclic, for example if the @option{wrap} option is
254 @item hls_flags single_file
255 If this flag is set, the muxer will store all segments in a single MPEG-TS
256 file, and will use byte ranges in the playlist. HLS playlists generated with
257 this way will have the version number 4.
260 ffmpeg -i in.nut -hls_flags single_file out.m3u8
262 Will produce the playlist, @file{out.m3u8}, and a single segment file,
271 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
275 Size cannot exceed 256 pixels in any dimension
278 Only BMP and PNG images can be stored
281 If a BMP image is used, it must be one of the following pixel formats:
283 BMP Bit Depth FFmpeg Pixel Format
293 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
296 If a PNG image is used, it must use the rgba pixel format
304 The image file muxer writes video frames to image files.
306 The output filenames are specified by a pattern, which can be used to
307 produce sequentially numbered series of files.
308 The pattern may contain the string "%d" or "%0@var{N}d", this string
309 specifies the position of the characters representing a numbering in
310 the filenames. If the form "%0@var{N}d" is used, the string
311 representing the number in each filename is 0-padded to @var{N}
312 digits. The literal character '%' can be specified in the pattern with
315 If the pattern contains "%d" or "%0@var{N}d", the first filename of
316 the file list specified will contain the number 1, all the following
317 numbers will be sequential.
319 The pattern may contain a suffix which is used to automatically
320 determine the format of the image files to write.
322 For example the pattern "img-%03d.bmp" will specify a sequence of
323 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
324 @file{img-010.bmp}, etc.
325 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
326 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
331 The following example shows how to use @command{ffmpeg} for creating a
332 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
333 taking one image every second from the input video:
335 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
338 Note that with @command{ffmpeg}, if the format is not specified with the
339 @code{-f} option and the output filename specifies an image file
340 format, the image2 muxer is automatically selected, so the previous
341 command can be written as:
343 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
346 Note also that the pattern must not necessarily contain "%d" or
347 "%0@var{N}d", for example to create a single image file
348 @file{img.jpeg} from the input video you can employ the command:
350 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
353 The @option{strftime} option allows you to expand the filename with
354 date and time information. Check the documentation of
355 the @code{strftime()} function for the syntax.
357 For example to generate image files from the @code{strftime()}
358 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
361 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
368 Start the sequence from the specified number. Default value is 1. Must
369 be a non-negative number.
372 If set to 1, the filename will always be interpreted as just a
373 filename, not a pattern, and the corresponding file will be continuously
374 overwritten with new images. Default value is 0.
377 If set to 1, expand the filename with date and time information from
378 @code{strftime()}. Default value is 0.
381 The image muxer supports the .Y.U.V image file format. This format is
382 special in that that each image frame consists of three files, for
383 each of the YUV420P components. To read or write this image file format,
384 specify the name of the '.Y' file. The muxer will automatically open the
385 '.U' and '.V' files as required.
389 Matroska container muxer.
391 This muxer implements the matroska and webm container specs.
395 The recognized metadata settings in this muxer are:
399 Set title name provided to a single track.
402 Specify the language of the track in the Matroska languages form.
404 The language can be either the 3 letters bibliographic ISO-639-2 (ISO
405 639-2/B) form (like "fre" for French), or a language code mixed with a
406 country code for specialities in languages (like "fre-ca" for Canadian
410 Set stereo 3D video layout of two views in a single video track.
412 The following values are recognized:
417 Both views are arranged side by side, Left-eye view is on the left
419 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
421 Both views are arranged in top-bottom orientation, Left-eye view is on top
422 @item checkerboard_rl
423 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
424 @item checkerboard_lr
425 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
426 @item row_interleaved_rl
427 Each view is constituted by a row based interleaving, Right-eye view is first row
428 @item row_interleaved_lr
429 Each view is constituted by a row based interleaving, Left-eye view is first row
430 @item col_interleaved_rl
431 Both views are arranged in a column based interleaving manner, Right-eye view is first column
432 @item col_interleaved_lr
433 Both views are arranged in a column based interleaving manner, Left-eye view is first column
434 @item anaglyph_cyan_red
435 All frames are in anaglyph format viewable through red-cyan filters
437 Both views are arranged side by side, Right-eye view is on the left
438 @item anaglyph_green_magenta
439 All frames are in anaglyph format viewable through green-magenta filters
441 Both eyes laced in one Block, Left-eye view is first
443 Both eyes laced in one Block, Right-eye view is first
447 For example a 3D WebM clip can be created using the following command line:
449 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
454 This muxer supports the following options:
457 @item reserve_index_space
458 By default, this muxer writes the index for seeking (called cues in Matroska
459 terms) at the end of the file, because it cannot know in advance how much space
460 to leave for the index at the beginning of the file. However for some use cases
461 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
462 index at the beginning of the file.
464 If this option is set to a non-zero value, the muxer will reserve a given amount
465 of space in the file header and then try to write the cues there when the muxing
466 finishes. If the available space does not suffice, muxing will fail. A safe size
467 for most use cases should be about 50kB per hour of video.
469 Note that cues are only written if the output is seekable and this option will
470 have no effect if it is not.
478 This muxer computes and prints the MD5 hash of all the input audio
479 and video frames. By default audio frames are converted to signed
480 16-bit raw audio and video frames to raw video before computing the
483 The output of the muxer consists of a single line of the form:
484 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
485 the computed MD5 hash.
487 For example to compute the MD5 hash of the input converted to raw
488 audio and video, and store it in the file @file{out.md5}:
490 ffmpeg -i INPUT -f md5 out.md5
493 You can print the MD5 to stdout with the command:
495 ffmpeg -i INPUT -f md5 -
498 See also the @ref{framemd5} muxer.
500 @section mov, mp4, ismv
502 MOV/MP4/ISMV (Smooth Streaming) muxer.
504 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
505 file has all the metadata about all packets stored in one location
506 (written at the end of the file, it can be moved to the start for
507 better playback by adding @var{faststart} to the @var{movflags}, or
508 using the @command{qt-faststart} tool). A fragmented
509 file consists of a number of fragments, where packets and metadata
510 about these packets are stored together. Writing a fragmented
511 file has the advantage that the file is decodable even if the
512 writing is interrupted (while a normal MOV/MP4 is undecodable if
513 it is not properly finished), and it requires less memory when writing
514 very long files (since writing normal MOV/MP4 files stores info about
515 every single packet in memory until the file is closed). The downside
516 is that it is less compatible with other applications.
520 Fragmentation is enabled by setting one of the AVOptions that define
521 how to cut the file into fragments:
524 @item -moov_size @var{bytes}
525 Reserves space for the moov atom at the beginning of the file instead of placing the
526 moov atom at the end. If the space reserved is insufficient, muxing will fail.
527 @item -movflags frag_keyframe
528 Start a new fragment at each video keyframe.
529 @item -frag_duration @var{duration}
530 Create fragments that are @var{duration} microseconds long.
531 @item -frag_size @var{size}
532 Create fragments that contain up to @var{size} bytes of payload data.
533 @item -movflags frag_custom
534 Allow the caller to manually choose when to cut fragments, by
535 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
536 the packets written so far. (This is only useful with other
537 applications integrating libavformat, not from @command{ffmpeg}.)
538 @item -min_frag_duration @var{duration}
539 Don't create fragments that are shorter than @var{duration} microseconds long.
542 If more than one condition is specified, fragments are cut when
543 one of the specified conditions is fulfilled. The exception to this is
544 @code{-min_frag_duration}, which has to be fulfilled for any of the other
547 Additionally, the way the output file is written can be adjusted
548 through a few other options:
551 @item -movflags empty_moov
552 Write an initial moov atom directly at the start of the file, without
553 describing any samples in it. Generally, an mdat/moov pair is written
554 at the start of the file, as a normal MOV/MP4 file, containing only
555 a short portion of the file. With this option set, there is no initial
556 mdat atom, and the moov atom only describes the tracks but has
559 Files written with this option set do not work in QuickTime.
560 This option is implicitly set when writing ismv (Smooth Streaming) files.
561 @item -movflags separate_moof
562 Write a separate moof (movie fragment) atom for each track. Normally,
563 packets for all tracks are written in a moof atom (which is slightly
564 more efficient), but with this option set, the muxer writes one moof/mdat
565 pair for each track, making it easier to separate tracks.
567 This option is implicitly set when writing ismv (Smooth Streaming) files.
568 @item -movflags faststart
569 Run a second pass moving the index (moov atom) to the beginning of the file.
570 This operation can take a while, and will not work in various situations such
571 as fragmented output, thus it is not enabled by default.
572 @item -movflags rtphint
573 Add RTP hinting tracks to the output file.
574 @item -movflags disable_chpl
575 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
576 and a QuickTime chapter track are written to the file. With this option
577 set, only the QuickTime chapter track will be written. Nero chapters can
578 cause failures when the file is reprocessed with certain tagging programs, like
579 mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
584 Smooth Streaming content can be pushed in real time to a publishing
585 point on IIS with this muxer. Example:
587 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
592 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
593 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
594 @code{id3v2_version} option controls which one is used. Setting
595 @code{id3v2_version} to 0 will disable the ID3v2 header completely. The legacy
596 ID3v1 tag is not written by default, but may be enabled with the
597 @code{write_id3v1} option.
599 The muxer may also write a Xing frame at the beginning, which contains the
600 number of frames in the file. It is useful for computing duration of VBR files.
601 The Xing frame is written if the output stream is seekable and if the
602 @code{write_xing} option is set to 1 (the default).
604 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
605 are supplied to the muxer in form of a video stream with a single packet. There
606 can be any number of those streams, each will correspond to a single APIC frame.
607 The stream metadata tags @var{title} and @var{comment} map to APIC
608 @var{description} and @var{picture type} respectively. See
609 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
611 Note that the APIC frames must be written at the beginning, so the muxer will
612 buffer the audio frames until it gets all the pictures. It is therefore advised
613 to provide the pictures as soon as possible to avoid excessive buffering.
617 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
619 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
622 To attach a picture to an mp3 file select both the audio and the picture stream
625 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
626 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
629 Write a "clean" MP3 without any extra features:
631 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
636 MPEG transport stream muxer.
638 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
640 The recognized metadata settings in mpegts muxer are @code{service_provider}
641 and @code{service_name}. If they are not set the default for
642 @code{service_provider} is "FFmpeg" and the default for
643 @code{service_name} is "Service01".
647 The muxer options are:
650 @item -mpegts_original_network_id @var{number}
651 Set the original_network_id (default 0x0001). This is unique identifier
652 of a network in DVB. Its main use is in the unique identification of a
653 service through the path Original_Network_ID, Transport_Stream_ID.
654 @item -mpegts_transport_stream_id @var{number}
655 Set the transport_stream_id (default 0x0001). This identifies a
657 @item -mpegts_service_id @var{number}
658 Set the service_id (default 0x0001) also known as program in DVB.
659 @item -mpegts_pmt_start_pid @var{number}
660 Set the first PID for PMT (default 0x1000, max 0x1f00).
661 @item -mpegts_start_pid @var{number}
662 Set the first PID for data packets (default 0x0100, max 0x0f00).
663 @item -mpegts_m2ts_mode @var{number}
664 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
665 @item -muxrate @var{number}
666 Set a constant muxrate (default VBR).
667 @item -pcr_period @var{numer}
668 Override the default PCR retransmission time (default 20ms), ignored
669 if variable muxrate is selected.
670 @item -pes_payload_size @var{number}
671 Set minimum PES packet payload in bytes.
672 @item -mpegts_flags @var{flags}
673 Set flags (see below).
674 @item -mpegts_copyts @var{number}
675 Preserve original timestamps, if value is set to 1. Default value is -1, which
676 results in shifting timestamps so that they start from 0.
677 @item -tables_version @var{number}
678 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
679 This option allows updating stream structure so that standard consumer may
680 detect the change. To do so, reopen output AVFormatContext (in case of API
681 usage) or restart ffmpeg instance, cyclically changing tables_version value:
683 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
684 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
686 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
687 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
688 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
693 Option mpegts_flags may take a set of such flags:
697 Reemit PAT/PMT before writing the next packet.
699 Use LATM packetization for AAC.
705 ffmpeg -i file.mpg -c copy \
706 -mpegts_original_network_id 0x1122 \
707 -mpegts_transport_stream_id 0x3344 \
708 -mpegts_service_id 0x5566 \
709 -mpegts_pmt_start_pid 0x1500 \
710 -mpegts_start_pid 0x150 \
711 -metadata service_provider="Some provider" \
712 -metadata service_name="Some Channel" \
720 This muxer does not generate any output file, it is mainly useful for
721 testing or benchmarking purposes.
723 For example to benchmark decoding with @command{ffmpeg} you can use the
726 ffmpeg -benchmark -i INPUT -f null out.null
729 Note that the above command does not read or write the @file{out.null}
730 file, but specifying the output file is required by the @command{ffmpeg}
733 Alternatively you can write the command as:
735 ffmpeg -benchmark -i INPUT -f null -
741 @item -syncpoints @var{flags}
742 Change the syncpoint usage in nut:
744 @item @var{default} use the normal low-overhead seeking aids.
745 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
746 Use of this option is not recommended, as the resulting files are very damage
747 sensitive and seeking is not possible. Also in general the overhead from
748 syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
749 all growing data tables, allowing to mux endless streams with limited memory
750 and wihout these disadvantages.
751 @item @var{timestamped} extend the syncpoint with a wallclock field.
753 The @var{none} and @var{timestamped} flags are experimental.
754 @item -write_index @var{bool}
755 Write index at the end, the default is to write an index.
759 ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
767 @item -page_duration @var{duration}
768 Preferred page duration, in microseconds. The muxer will attempt to create
769 pages that are approximately @var{duration} microseconds long. This allows the
770 user to compromise between seek granularity and container overhead. The default
771 is 1 second. A value of 0 will fill all segments, making pages as large as
772 possible. A value of 1 will effectively use 1 packet-per-page in most
773 situations, giving a small seek granularity at the cost of additional container
778 @section segment, stream_segment, ssegment
780 Basic stream segmenter.
782 This muxer outputs streams to a number of separate files of nearly
783 fixed duration. Output filename pattern can be set in a fashion similar to
786 @code{stream_segment} is a variant of the muxer used to write to
787 streaming output formats, i.e. which do not require global headers,
788 and is recommended for outputting e.g. to MPEG transport stream segments.
789 @code{ssegment} is a shorter alias for @code{stream_segment}.
791 Every segment starts with a keyframe of the selected reference stream,
792 which is set through the @option{reference_stream} option.
794 Note that if you want accurate splitting for a video file, you need to
795 make the input key frames correspond to the exact splitting times
796 expected by the segmenter, or the segment muxer will start the new
797 segment with the key frame found next after the specified start
800 The segment muxer works best with a single constant frame rate video.
802 Optionally it can generate a list of the created segments, by setting
803 the option @var{segment_list}. The list type is specified by the
804 @var{segment_list_type} option. The entry filenames in the segment
805 list are set by default to the basename of the corresponding segment
808 See also the @ref{hls} muxer, which provides a more specific
809 implementation for HLS segmentation.
813 The segment muxer supports the following options:
816 @item reference_stream @var{specifier}
817 Set the reference stream, as specified by the string @var{specifier}.
818 If @var{specifier} is set to @code{auto}, the reference is chosen
819 automatically. Otherwise it must be a stream specifier (see the ``Stream
820 specifiers'' chapter in the ffmpeg manual) which specifies the
821 reference stream. The default value is @code{auto}.
823 @item segment_format @var{format}
824 Override the inner container format, by default it is guessed by the filename
827 @item segment_format_options @var{options_list}
828 Set output format options using a :-separated list of key=value
829 parameters. Values containing the @code{:} special character must be
832 @item segment_list @var{name}
833 Generate also a listfile named @var{name}. If not specified no
834 listfile is generated.
836 @item segment_list_flags @var{flags}
837 Set flags affecting the segment list generation.
839 It currently supports the following flags:
842 Allow caching (only affects M3U8 list files).
845 Allow live-friendly file generation.
848 @item segment_list_type @var{type}
849 Select the listing format.
851 @item @var{flat} use a simple flat list of entries.
852 @item @var{hls} use a m3u8-like structure.
855 @item segment_list_size @var{size}
856 Update the list file so that it contains at most @var{size}
857 segments. If 0 the list file will contain all the segments. Default
860 @item segment_list_entry_prefix @var{prefix}
861 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
862 By default no prefix is applied.
864 The following values are recognized:
867 Generate a flat list for the created segments, one segment per line.
870 Generate a list for the created segments, one segment per line,
871 each line matching the format (comma-separated values):
873 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
876 @var{segment_filename} is the name of the output file generated by the
877 muxer according to the provided pattern. CSV escaping (according to
878 RFC4180) is applied if required.
880 @var{segment_start_time} and @var{segment_end_time} specify
881 the segment start and end time expressed in seconds.
883 A list file with the suffix @code{".csv"} or @code{".ext"} will
884 auto-select this format.
886 @samp{ext} is deprecated in favor or @samp{csv}.
889 Generate an ffconcat file for the created segments. The resulting file
890 can be read using the FFmpeg @ref{concat} demuxer.
892 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
893 auto-select this format.
896 Generate an extended M3U8 file, version 3, compliant with
897 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
899 A list file with the suffix @code{".m3u8"} will auto-select this format.
902 If not specified the type is guessed from the list file name suffix.
904 @item segment_time @var{time}
905 Set segment duration to @var{time}, the value must be a duration
906 specification. Default value is "2". See also the
907 @option{segment_times} option.
909 Note that splitting may not be accurate, unless you force the
910 reference stream key-frames at the given time. See the introductory
911 notice and the examples below.
913 @item segment_atclocktime @var{1|0}
914 If set to "1" split at regular clock time intervals starting from 00:00
915 o'clock. The @var{time} value specified in @option{segment_time} is
916 used for setting the length of the splitting interval.
918 For example with @option{segment_time} set to "900" this makes it possible
919 to create files at 12:00 o'clock, 12:15, 12:30, etc.
921 Default value is "0".
923 @item segment_time_delta @var{delta}
924 Specify the accuracy time when selecting the start time for a
925 segment, expressed as a duration specification. Default value is "0".
927 When delta is specified a key-frame will start a new segment if its
928 PTS satisfies the relation:
930 PTS >= start_time - time_delta
933 This option is useful when splitting video content, which is always
934 split at GOP boundaries, in case a key frame is found just before the
935 specified split time.
937 In particular may be used in combination with the @file{ffmpeg} option
938 @var{force_key_frames}. The key frame times specified by
939 @var{force_key_frames} may not be set accurately because of rounding
940 issues, with the consequence that a key frame time may result set just
941 before the specified time. For constant frame rate videos a value of
942 1/(2*@var{frame_rate}) should address the worst case mismatch between
943 the specified time and the time set by @var{force_key_frames}.
945 @item segment_times @var{times}
946 Specify a list of split points. @var{times} contains a list of comma
947 separated duration specifications, in increasing order. See also
948 the @option{segment_time} option.
950 @item segment_frames @var{frames}
951 Specify a list of split video frame numbers. @var{frames} contains a
952 list of comma separated integer numbers, in increasing order.
954 This option specifies to start a new segment whenever a reference
955 stream key frame is found and the sequential number (starting from 0)
956 of the frame is greater or equal to the next value in the list.
958 @item segment_wrap @var{limit}
959 Wrap around segment index once it reaches @var{limit}.
961 @item segment_start_number @var{number}
962 Set the sequence number of the first segment. Defaults to @code{0}.
964 @item reset_timestamps @var{1|0}
965 Reset timestamps at the begin of each segment, so that each segment
966 will start with near-zero timestamps. It is meant to ease the playback
967 of the generated segments. May not work with some combinations of
968 muxers/codecs. It is set to @code{0} by default.
970 @item initial_offset @var{offset}
971 Specify timestamp offset to apply to the output packet timestamps. The
972 argument must be a time duration specification, and defaults to 0.
979 Remux the content of file @file{in.mkv} to a list of segments
980 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
981 generated segments to @file{out.list}:
983 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
987 Segment input and set output format options for the output segments:
989 ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
993 Segment the input file according to the split points specified by the
994 @var{segment_times} option:
996 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
1000 Use the @command{ffmpeg} @option{force_key_frames}
1001 option to force key frames in the input at the specified location, together
1002 with the segment option @option{segment_time_delta} to account for
1003 possible roundings operated when setting key frame times.
1005 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
1006 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
1008 In order to force key frames on the input file, transcoding is
1012 Segment the input file by splitting the input file according to the
1013 frame numbers sequence specified with the @option{segment_frames} option:
1015 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
1019 Convert the @file{in.mkv} to TS segments using the @code{libx264}
1020 and @code{libfaac} encoders:
1022 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
1026 Segment the input file, and create an M3U8 live playlist (can be used
1027 as live HLS source):
1029 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
1030 -segment_list_flags +live -segment_time 10 out%03d.mkv
1034 @section smoothstreaming
1036 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
1040 Specify the number of fragments kept in the manifest. Default 0 (keep all).
1042 @item extra_window_size
1043 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
1045 @item lookahead_count
1046 Specify the number of lookahead fragments. Default 2.
1048 @item min_frag_duration
1049 Specify the minimum fragment duration (in microseconds). Default 5000000.
1051 @item remove_at_exit
1052 Specify whether to remove all fragments when finished. Default 0 (do not remove).
1058 The tee muxer can be used to write the same data to several files or any
1059 other kind of muxer. It can be used, for example, to both stream a video to
1060 the network and save it to disk at the same time.
1062 It is different from specifying several outputs to the @command{ffmpeg}
1063 command-line tool because the audio and video data will be encoded only once
1064 with the tee muxer; encoding can be a very expensive process. It is not
1065 useful when using the libavformat API directly because it is then possible
1066 to feed the same packets to several muxers directly.
1068 The slave outputs are specified in the file name given to the muxer,
1069 separated by '|'. If any of the slave name contains the '|' separator,
1070 leading or trailing spaces or any special character, it must be
1071 escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
1072 section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
1074 Muxer options can be specified for each slave by prepending them as a list of
1075 @var{key}=@var{value} pairs separated by ':', between square brackets. If
1076 the options values contain a special character or the ':' separator, they
1077 must be escaped; note that this is a second level escaping.
1079 The following special options are also recognized:
1082 Specify the format name. Useful if it cannot be guessed from the
1085 @item bsfs[/@var{spec}]
1086 Specify a list of bitstream filters to apply to the specified
1089 It is possible to specify to which streams a given bitstream filter
1090 applies, by appending a stream specifier to the option separated by
1091 @code{/}. @var{spec} must be a stream specifier (see @ref{Format
1092 stream specifiers}). If the stream specifier is not specified, the
1093 bitstream filters will be applied to all streams in the output.
1095 Several bitstream filters can be specified, separated by ",".
1098 Select the streams that should be mapped to the slave output,
1099 specified by a stream specifier. If not specified, this defaults to
1100 all the input streams.
1103 @subsection Examples
1107 Encode something and both archive it in a WebM file and stream it
1108 as MPEG-TS over UDP (the streams need to be explicitly mapped):
1110 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
1111 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
1115 Use @command{ffmpeg} to encode the input, and send the output
1116 to three different destinations. The @code{dump_extra} bitstream
1117 filter is used to add extradata information to all the output video
1118 keyframes packets, as requested by the MPEG-TS format. The select
1119 option is applied to @file{out.aac} in order to make it contain only
1122 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1123 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
1127 As below, but select only stream @code{a:1} for the audio output. Note
1128 that a second level escaping must be performed, as ":" is a special
1129 character used to separate options.
1131 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1132 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
1136 Note: some codecs may need different options depending on the output format;
1137 the auto-detection of this can not work with the tee muxer. The main example
1138 is the @option{global_header} flag.
1140 @section webm_dash_manifest
1142 WebM DASH Manifest muxer.
1144 This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
1148 This muxer supports the following options:
1151 @item adaptation_sets
1152 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
1153 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
1154 audio and video streams. Any number of adaptation sets can be added using this option.
1159 ffmpeg -f webm_dash_manifest -i video1.webm \
1160 -f webm_dash_manifest -i video2.webm \
1161 -f webm_dash_manifest -i audio1.webm \
1162 -f webm_dash_manifest -i audio2.webm \
1163 -map 0 -map 1 -map 2 -map 3 \
1165 -f webm_dash_manifest \
1166 -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \