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
249 @item hls_base_url @var{baseurl}
250 Append @var{baseurl} to every entry in the playlist.
251 Useful to generate playlists with absolute paths.
253 Note that the playlist sequence number must be unique for each segment
254 and it is not to be confused with the segment filename sequence number
255 which can be cyclic, for example if the @option{wrap} option is
258 @item hls_flags single_file
259 If this flag is set, the muxer will store all segments in a single MPEG-TS
260 file, and will use byte ranges in the playlist. HLS playlists generated with
261 this way will have the version number 4.
264 ffmpeg -i in.nut -hls_flags single_file out.m3u8
266 Will produce the playlist, @file{out.m3u8}, and a single segment file,
275 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
279 Size cannot exceed 256 pixels in any dimension
282 Only BMP and PNG images can be stored
285 If a BMP image is used, it must be one of the following pixel formats:
287 BMP Bit Depth FFmpeg Pixel Format
297 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
300 If a PNG image is used, it must use the rgba pixel format
308 The image file muxer writes video frames to image files.
310 The output filenames are specified by a pattern, which can be used to
311 produce sequentially numbered series of files.
312 The pattern may contain the string "%d" or "%0@var{N}d", this string
313 specifies the position of the characters representing a numbering in
314 the filenames. If the form "%0@var{N}d" is used, the string
315 representing the number in each filename is 0-padded to @var{N}
316 digits. The literal character '%' can be specified in the pattern with
319 If the pattern contains "%d" or "%0@var{N}d", the first filename of
320 the file list specified will contain the number 1, all the following
321 numbers will be sequential.
323 The pattern may contain a suffix which is used to automatically
324 determine the format of the image files to write.
326 For example the pattern "img-%03d.bmp" will specify a sequence of
327 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
328 @file{img-010.bmp}, etc.
329 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
330 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
335 The following example shows how to use @command{ffmpeg} for creating a
336 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
337 taking one image every second from the input video:
339 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
342 Note that with @command{ffmpeg}, if the format is not specified with the
343 @code{-f} option and the output filename specifies an image file
344 format, the image2 muxer is automatically selected, so the previous
345 command can be written as:
347 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
350 Note also that the pattern must not necessarily contain "%d" or
351 "%0@var{N}d", for example to create a single image file
352 @file{img.jpeg} from the input video you can employ the command:
354 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
357 The @option{strftime} option allows you to expand the filename with
358 date and time information. Check the documentation of
359 the @code{strftime()} function for the syntax.
361 For example to generate image files from the @code{strftime()}
362 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
365 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
372 Start the sequence from the specified number. Default value is 1. Must
373 be a non-negative number.
376 If set to 1, the filename will always be interpreted as just a
377 filename, not a pattern, and the corresponding file will be continuously
378 overwritten with new images. Default value is 0.
381 If set to 1, expand the filename with date and time information from
382 @code{strftime()}. Default value is 0.
385 The image muxer supports the .Y.U.V image file format. This format is
386 special in that that each image frame consists of three files, for
387 each of the YUV420P components. To read or write this image file format,
388 specify the name of the '.Y' file. The muxer will automatically open the
389 '.U' and '.V' files as required.
393 Matroska container muxer.
395 This muxer implements the matroska and webm container specs.
399 The recognized metadata settings in this muxer are:
403 Set title name provided to a single track.
406 Specify the language of the track in the Matroska languages form.
408 The language can be either the 3 letters bibliographic ISO-639-2 (ISO
409 639-2/B) form (like "fre" for French), or a language code mixed with a
410 country code for specialities in languages (like "fre-ca" for Canadian
414 Set stereo 3D video layout of two views in a single video track.
416 The following values are recognized:
421 Both views are arranged side by side, Left-eye view is on the left
423 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
425 Both views are arranged in top-bottom orientation, Left-eye view is on top
426 @item checkerboard_rl
427 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
428 @item checkerboard_lr
429 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
430 @item row_interleaved_rl
431 Each view is constituted by a row based interleaving, Right-eye view is first row
432 @item row_interleaved_lr
433 Each view is constituted by a row based interleaving, Left-eye view is first row
434 @item col_interleaved_rl
435 Both views are arranged in a column based interleaving manner, Right-eye view is first column
436 @item col_interleaved_lr
437 Both views are arranged in a column based interleaving manner, Left-eye view is first column
438 @item anaglyph_cyan_red
439 All frames are in anaglyph format viewable through red-cyan filters
441 Both views are arranged side by side, Right-eye view is on the left
442 @item anaglyph_green_magenta
443 All frames are in anaglyph format viewable through green-magenta filters
445 Both eyes laced in one Block, Left-eye view is first
447 Both eyes laced in one Block, Right-eye view is first
451 For example a 3D WebM clip can be created using the following command line:
453 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
458 This muxer supports the following options:
461 @item reserve_index_space
462 By default, this muxer writes the index for seeking (called cues in Matroska
463 terms) at the end of the file, because it cannot know in advance how much space
464 to leave for the index at the beginning of the file. However for some use cases
465 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
466 index at the beginning of the file.
468 If this option is set to a non-zero value, the muxer will reserve a given amount
469 of space in the file header and then try to write the cues there when the muxing
470 finishes. If the available space does not suffice, muxing will fail. A safe size
471 for most use cases should be about 50kB per hour of video.
473 Note that cues are only written if the output is seekable and this option will
474 have no effect if it is not.
482 This muxer computes and prints the MD5 hash of all the input audio
483 and video frames. By default audio frames are converted to signed
484 16-bit raw audio and video frames to raw video before computing the
487 The output of the muxer consists of a single line of the form:
488 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
489 the computed MD5 hash.
491 For example to compute the MD5 hash of the input converted to raw
492 audio and video, and store it in the file @file{out.md5}:
494 ffmpeg -i INPUT -f md5 out.md5
497 You can print the MD5 to stdout with the command:
499 ffmpeg -i INPUT -f md5 -
502 See also the @ref{framemd5} muxer.
504 @section mov, mp4, ismv
506 MOV/MP4/ISMV (Smooth Streaming) muxer.
508 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
509 file has all the metadata about all packets stored in one location
510 (written at the end of the file, it can be moved to the start for
511 better playback by adding @var{faststart} to the @var{movflags}, or
512 using the @command{qt-faststart} tool). A fragmented
513 file consists of a number of fragments, where packets and metadata
514 about these packets are stored together. Writing a fragmented
515 file has the advantage that the file is decodable even if the
516 writing is interrupted (while a normal MOV/MP4 is undecodable if
517 it is not properly finished), and it requires less memory when writing
518 very long files (since writing normal MOV/MP4 files stores info about
519 every single packet in memory until the file is closed). The downside
520 is that it is less compatible with other applications.
524 Fragmentation is enabled by setting one of the AVOptions that define
525 how to cut the file into fragments:
528 @item -moov_size @var{bytes}
529 Reserves space for the moov atom at the beginning of the file instead of placing the
530 moov atom at the end. If the space reserved is insufficient, muxing will fail.
531 @item -movflags frag_keyframe
532 Start a new fragment at each video keyframe.
533 @item -frag_duration @var{duration}
534 Create fragments that are @var{duration} microseconds long.
535 @item -frag_size @var{size}
536 Create fragments that contain up to @var{size} bytes of payload data.
537 @item -movflags frag_custom
538 Allow the caller to manually choose when to cut fragments, by
539 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
540 the packets written so far. (This is only useful with other
541 applications integrating libavformat, not from @command{ffmpeg}.)
542 @item -min_frag_duration @var{duration}
543 Don't create fragments that are shorter than @var{duration} microseconds long.
546 If more than one condition is specified, fragments are cut when
547 one of the specified conditions is fulfilled. The exception to this is
548 @code{-min_frag_duration}, which has to be fulfilled for any of the other
551 Additionally, the way the output file is written can be adjusted
552 through a few other options:
555 @item -movflags empty_moov
556 Write an initial moov atom directly at the start of the file, without
557 describing any samples in it. Generally, an mdat/moov pair is written
558 at the start of the file, as a normal MOV/MP4 file, containing only
559 a short portion of the file. With this option set, there is no initial
560 mdat atom, and the moov atom only describes the tracks but has
563 Files written with this option set do not work in QuickTime.
564 This option is implicitly set when writing ismv (Smooth Streaming) files.
565 @item -movflags separate_moof
566 Write a separate moof (movie fragment) atom for each track. Normally,
567 packets for all tracks are written in a moof atom (which is slightly
568 more efficient), but with this option set, the muxer writes one moof/mdat
569 pair for each track, making it easier to separate tracks.
571 This option is implicitly set when writing ismv (Smooth Streaming) files.
572 @item -movflags faststart
573 Run a second pass moving the index (moov atom) to the beginning of the file.
574 This operation can take a while, and will not work in various situations such
575 as fragmented output, thus it is not enabled by default.
576 @item -movflags rtphint
577 Add RTP hinting tracks to the output file.
578 @item -movflags disable_chpl
579 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
580 and a QuickTime chapter track are written to the file. With this option
581 set, only the QuickTime chapter track will be written. Nero chapters can
582 cause failures when the file is reprocessed with certain tagging programs, like
583 mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
588 Smooth Streaming content can be pushed in real time to a publishing
589 point on IIS with this muxer. Example:
591 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
596 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
597 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
598 @code{id3v2_version} option controls which one is used. Setting
599 @code{id3v2_version} to 0 will disable the ID3v2 header completely. The legacy
600 ID3v1 tag is not written by default, but may be enabled with the
601 @code{write_id3v1} option.
603 The muxer may also write a Xing frame at the beginning, which contains the
604 number of frames in the file. It is useful for computing duration of VBR files.
605 The Xing frame is written if the output stream is seekable and if the
606 @code{write_xing} option is set to 1 (the default).
608 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
609 are supplied to the muxer in form of a video stream with a single packet. There
610 can be any number of those streams, each will correspond to a single APIC frame.
611 The stream metadata tags @var{title} and @var{comment} map to APIC
612 @var{description} and @var{picture type} respectively. See
613 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
615 Note that the APIC frames must be written at the beginning, so the muxer will
616 buffer the audio frames until it gets all the pictures. It is therefore advised
617 to provide the pictures as soon as possible to avoid excessive buffering.
621 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
623 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
626 To attach a picture to an mp3 file select both the audio and the picture stream
629 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
630 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
633 Write a "clean" MP3 without any extra features:
635 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
640 MPEG transport stream muxer.
642 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
644 The recognized metadata settings in mpegts muxer are @code{service_provider}
645 and @code{service_name}. If they are not set the default for
646 @code{service_provider} is "FFmpeg" and the default for
647 @code{service_name} is "Service01".
651 The muxer options are:
654 @item -mpegts_original_network_id @var{number}
655 Set the original_network_id (default 0x0001). This is unique identifier
656 of a network in DVB. Its main use is in the unique identification of a
657 service through the path Original_Network_ID, Transport_Stream_ID.
658 @item -mpegts_transport_stream_id @var{number}
659 Set the transport_stream_id (default 0x0001). This identifies a
661 @item -mpegts_service_id @var{number}
662 Set the service_id (default 0x0001) also known as program in DVB.
663 @item -mpegts_pmt_start_pid @var{number}
664 Set the first PID for PMT (default 0x1000, max 0x1f00).
665 @item -mpegts_start_pid @var{number}
666 Set the first PID for data packets (default 0x0100, max 0x0f00).
667 @item -mpegts_m2ts_mode @var{number}
668 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
669 @item -muxrate @var{number}
670 Set a constant muxrate (default VBR).
671 @item -pcr_period @var{numer}
672 Override the default PCR retransmission time (default 20ms), ignored
673 if variable muxrate is selected.
674 @item -pes_payload_size @var{number}
675 Set minimum PES packet payload in bytes.
676 @item -mpegts_flags @var{flags}
677 Set flags (see below).
678 @item -mpegts_copyts @var{number}
679 Preserve original timestamps, if value is set to 1. Default value is -1, which
680 results in shifting timestamps so that they start from 0.
681 @item -tables_version @var{number}
682 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
683 This option allows updating stream structure so that standard consumer may
684 detect the change. To do so, reopen output AVFormatContext (in case of API
685 usage) or restart ffmpeg instance, cyclically changing tables_version value:
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
690 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
691 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
692 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
697 Option mpegts_flags may take a set of such flags:
701 Reemit PAT/PMT before writing the next packet.
703 Use LATM packetization for AAC.
709 ffmpeg -i file.mpg -c copy \
710 -mpegts_original_network_id 0x1122 \
711 -mpegts_transport_stream_id 0x3344 \
712 -mpegts_service_id 0x5566 \
713 -mpegts_pmt_start_pid 0x1500 \
714 -mpegts_start_pid 0x150 \
715 -metadata service_provider="Some provider" \
716 -metadata service_name="Some Channel" \
724 This muxer does not generate any output file, it is mainly useful for
725 testing or benchmarking purposes.
727 For example to benchmark decoding with @command{ffmpeg} you can use the
730 ffmpeg -benchmark -i INPUT -f null out.null
733 Note that the above command does not read or write the @file{out.null}
734 file, but specifying the output file is required by the @command{ffmpeg}
737 Alternatively you can write the command as:
739 ffmpeg -benchmark -i INPUT -f null -
745 @item -syncpoints @var{flags}
746 Change the syncpoint usage in nut:
748 @item @var{default} use the normal low-overhead seeking aids.
749 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
750 Use of this option is not recommended, as the resulting files are very damage
751 sensitive and seeking is not possible. Also in general the overhead from
752 syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
753 all growing data tables, allowing to mux endless streams with limited memory
754 and wihout these disadvantages.
755 @item @var{timestamped} extend the syncpoint with a wallclock field.
757 The @var{none} and @var{timestamped} flags are experimental.
758 @item -write_index @var{bool}
759 Write index at the end, the default is to write an index.
763 ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
771 @item -page_duration @var{duration}
772 Preferred page duration, in microseconds. The muxer will attempt to create
773 pages that are approximately @var{duration} microseconds long. This allows the
774 user to compromise between seek granularity and container overhead. The default
775 is 1 second. A value of 0 will fill all segments, making pages as large as
776 possible. A value of 1 will effectively use 1 packet-per-page in most
777 situations, giving a small seek granularity at the cost of additional container
782 @section segment, stream_segment, ssegment
784 Basic stream segmenter.
786 This muxer outputs streams to a number of separate files of nearly
787 fixed duration. Output filename pattern can be set in a fashion similar to
790 @code{stream_segment} is a variant of the muxer used to write to
791 streaming output formats, i.e. which do not require global headers,
792 and is recommended for outputting e.g. to MPEG transport stream segments.
793 @code{ssegment} is a shorter alias for @code{stream_segment}.
795 Every segment starts with a keyframe of the selected reference stream,
796 which is set through the @option{reference_stream} option.
798 Note that if you want accurate splitting for a video file, you need to
799 make the input key frames correspond to the exact splitting times
800 expected by the segmenter, or the segment muxer will start the new
801 segment with the key frame found next after the specified start
804 The segment muxer works best with a single constant frame rate video.
806 Optionally it can generate a list of the created segments, by setting
807 the option @var{segment_list}. The list type is specified by the
808 @var{segment_list_type} option. The entry filenames in the segment
809 list are set by default to the basename of the corresponding segment
812 See also the @ref{hls} muxer, which provides a more specific
813 implementation for HLS segmentation.
817 The segment muxer supports the following options:
820 @item reference_stream @var{specifier}
821 Set the reference stream, as specified by the string @var{specifier}.
822 If @var{specifier} is set to @code{auto}, the reference is chosen
823 automatically. Otherwise it must be a stream specifier (see the ``Stream
824 specifiers'' chapter in the ffmpeg manual) which specifies the
825 reference stream. The default value is @code{auto}.
827 @item segment_format @var{format}
828 Override the inner container format, by default it is guessed by the filename
831 @item segment_format_options @var{options_list}
832 Set output format options using a :-separated list of key=value
833 parameters. Values containing the @code{:} special character must be
836 @item segment_list @var{name}
837 Generate also a listfile named @var{name}. If not specified no
838 listfile is generated.
840 @item segment_list_flags @var{flags}
841 Set flags affecting the segment list generation.
843 It currently supports the following flags:
846 Allow caching (only affects M3U8 list files).
849 Allow live-friendly file generation.
852 @item segment_list_type @var{type}
853 Select the listing format.
855 @item @var{flat} use a simple flat list of entries.
856 @item @var{hls} use a m3u8-like structure.
859 @item segment_list_size @var{size}
860 Update the list file so that it contains at most @var{size}
861 segments. If 0 the list file will contain all the segments. Default
864 @item segment_list_entry_prefix @var{prefix}
865 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
866 By default no prefix is applied.
868 The following values are recognized:
871 Generate a flat list for the created segments, one segment per line.
874 Generate a list for the created segments, one segment per line,
875 each line matching the format (comma-separated values):
877 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
880 @var{segment_filename} is the name of the output file generated by the
881 muxer according to the provided pattern. CSV escaping (according to
882 RFC4180) is applied if required.
884 @var{segment_start_time} and @var{segment_end_time} specify
885 the segment start and end time expressed in seconds.
887 A list file with the suffix @code{".csv"} or @code{".ext"} will
888 auto-select this format.
890 @samp{ext} is deprecated in favor or @samp{csv}.
893 Generate an ffconcat file for the created segments. The resulting file
894 can be read using the FFmpeg @ref{concat} demuxer.
896 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
897 auto-select this format.
900 Generate an extended M3U8 file, version 3, compliant with
901 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
903 A list file with the suffix @code{".m3u8"} will auto-select this format.
906 If not specified the type is guessed from the list file name suffix.
908 @item segment_time @var{time}
909 Set segment duration to @var{time}, the value must be a duration
910 specification. Default value is "2". See also the
911 @option{segment_times} option.
913 Note that splitting may not be accurate, unless you force the
914 reference stream key-frames at the given time. See the introductory
915 notice and the examples below.
917 @item segment_atclocktime @var{1|0}
918 If set to "1" split at regular clock time intervals starting from 00:00
919 o'clock. The @var{time} value specified in @option{segment_time} is
920 used for setting the length of the splitting interval.
922 For example with @option{segment_time} set to "900" this makes it possible
923 to create files at 12:00 o'clock, 12:15, 12:30, etc.
925 Default value is "0".
927 @item segment_time_delta @var{delta}
928 Specify the accuracy time when selecting the start time for a
929 segment, expressed as a duration specification. Default value is "0".
931 When delta is specified a key-frame will start a new segment if its
932 PTS satisfies the relation:
934 PTS >= start_time - time_delta
937 This option is useful when splitting video content, which is always
938 split at GOP boundaries, in case a key frame is found just before the
939 specified split time.
941 In particular may be used in combination with the @file{ffmpeg} option
942 @var{force_key_frames}. The key frame times specified by
943 @var{force_key_frames} may not be set accurately because of rounding
944 issues, with the consequence that a key frame time may result set just
945 before the specified time. For constant frame rate videos a value of
946 1/(2*@var{frame_rate}) should address the worst case mismatch between
947 the specified time and the time set by @var{force_key_frames}.
949 @item segment_times @var{times}
950 Specify a list of split points. @var{times} contains a list of comma
951 separated duration specifications, in increasing order. See also
952 the @option{segment_time} option.
954 @item segment_frames @var{frames}
955 Specify a list of split video frame numbers. @var{frames} contains a
956 list of comma separated integer numbers, in increasing order.
958 This option specifies to start a new segment whenever a reference
959 stream key frame is found and the sequential number (starting from 0)
960 of the frame is greater or equal to the next value in the list.
962 @item segment_wrap @var{limit}
963 Wrap around segment index once it reaches @var{limit}.
965 @item segment_start_number @var{number}
966 Set the sequence number of the first segment. Defaults to @code{0}.
968 @item reset_timestamps @var{1|0}
969 Reset timestamps at the begin of each segment, so that each segment
970 will start with near-zero timestamps. It is meant to ease the playback
971 of the generated segments. May not work with some combinations of
972 muxers/codecs. It is set to @code{0} by default.
974 @item initial_offset @var{offset}
975 Specify timestamp offset to apply to the output packet timestamps. The
976 argument must be a time duration specification, and defaults to 0.
983 Remux the content of file @file{in.mkv} to a list of segments
984 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
985 generated segments to @file{out.list}:
987 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
991 Segment input and set output format options for the output segments:
993 ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
997 Segment the input file according to the split points specified by the
998 @var{segment_times} option:
1000 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
1004 Use the @command{ffmpeg} @option{force_key_frames}
1005 option to force key frames in the input at the specified location, together
1006 with the segment option @option{segment_time_delta} to account for
1007 possible roundings operated when setting key frame times.
1009 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
1010 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
1012 In order to force key frames on the input file, transcoding is
1016 Segment the input file by splitting the input file according to the
1017 frame numbers sequence specified with the @option{segment_frames} option:
1019 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
1023 Convert the @file{in.mkv} to TS segments using the @code{libx264}
1024 and @code{libfaac} encoders:
1026 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
1030 Segment the input file, and create an M3U8 live playlist (can be used
1031 as live HLS source):
1033 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
1034 -segment_list_flags +live -segment_time 10 out%03d.mkv
1038 @section smoothstreaming
1040 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
1044 Specify the number of fragments kept in the manifest. Default 0 (keep all).
1046 @item extra_window_size
1047 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
1049 @item lookahead_count
1050 Specify the number of lookahead fragments. Default 2.
1052 @item min_frag_duration
1053 Specify the minimum fragment duration (in microseconds). Default 5000000.
1055 @item remove_at_exit
1056 Specify whether to remove all fragments when finished. Default 0 (do not remove).
1062 The tee muxer can be used to write the same data to several files or any
1063 other kind of muxer. It can be used, for example, to both stream a video to
1064 the network and save it to disk at the same time.
1066 It is different from specifying several outputs to the @command{ffmpeg}
1067 command-line tool because the audio and video data will be encoded only once
1068 with the tee muxer; encoding can be a very expensive process. It is not
1069 useful when using the libavformat API directly because it is then possible
1070 to feed the same packets to several muxers directly.
1072 The slave outputs are specified in the file name given to the muxer,
1073 separated by '|'. If any of the slave name contains the '|' separator,
1074 leading or trailing spaces or any special character, it must be
1075 escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
1076 section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
1078 Muxer options can be specified for each slave by prepending them as a list of
1079 @var{key}=@var{value} pairs separated by ':', between square brackets. If
1080 the options values contain a special character or the ':' separator, they
1081 must be escaped; note that this is a second level escaping.
1083 The following special options are also recognized:
1086 Specify the format name. Useful if it cannot be guessed from the
1089 @item bsfs[/@var{spec}]
1090 Specify a list of bitstream filters to apply to the specified
1093 It is possible to specify to which streams a given bitstream filter
1094 applies, by appending a stream specifier to the option separated by
1095 @code{/}. @var{spec} must be a stream specifier (see @ref{Format
1096 stream specifiers}). If the stream specifier is not specified, the
1097 bitstream filters will be applied to all streams in the output.
1099 Several bitstream filters can be specified, separated by ",".
1102 Select the streams that should be mapped to the slave output,
1103 specified by a stream specifier. If not specified, this defaults to
1104 all the input streams.
1107 @subsection Examples
1111 Encode something and both archive it in a WebM file and stream it
1112 as MPEG-TS over UDP (the streams need to be explicitly mapped):
1114 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
1115 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
1119 Use @command{ffmpeg} to encode the input, and send the output
1120 to three different destinations. The @code{dump_extra} bitstream
1121 filter is used to add extradata information to all the output video
1122 keyframes packets, as requested by the MPEG-TS format. The select
1123 option is applied to @file{out.aac} in order to make it contain only
1126 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1127 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
1131 As below, but select only stream @code{a:1} for the audio output. Note
1132 that a second level escaping must be performed, as ":" is a special
1133 character used to separate options.
1135 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1136 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
1140 Note: some codecs may need different options depending on the output format;
1141 the auto-detection of this can not work with the tee muxer. The main example
1142 is the @option{global_header} flag.
1144 @section webm_dash_manifest
1146 WebM DASH Manifest muxer.
1148 This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
1152 This muxer supports the following options:
1155 @item adaptation_sets
1156 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
1157 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
1158 audio and video streams. Any number of adaptation sets can be added using this option.
1163 ffmpeg -f webm_dash_manifest -i video1.webm \
1164 -f webm_dash_manifest -i video2.webm \
1165 -f webm_dash_manifest -i audio1.webm \
1166 -f webm_dash_manifest -i audio2.webm \
1167 -map 0 -map 1 -map 2 -map 3 \
1169 -f webm_dash_manifest \
1170 -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \