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 numbered segment files. The output
198 filename specifies the playlist filename; the segment filenames
199 receive the same basename as the playlist, a sequential number and
202 For example, to convert an input file with @command{ffmpeg}:
204 ffmpeg -i in.nut out.m3u8
207 See also the @ref{segment} muxer, which provides a more generic and
208 flexible implementation of a segmenter, and can be used to perform HLS
213 This muxer supports the following options:
216 @item hls_time @var{seconds}
217 Set the segment length in seconds. Default value is 2.
219 @item hls_list_size @var{size}
220 Set the maximum number of playlist entries. If set to 0 the list file
221 will contain all the segments. Default value is 5.
223 @item hls_wrap @var{wrap}
224 Set the number after which the segment filename number (the number
225 specified in each segment file) wraps. If set to 0 the number will be
226 never wrapped. Default value is 0.
228 This option is useful to avoid to fill the disk with many segment
229 files, and limits the maximum number of segment files written to disk
232 @item start_number @var{number}
233 Start the playlist sequence number from @var{number}. Default value is
236 @item hls_base_url @var{baseurl}
237 Append @var{baseurl} to every entry in the playlist.
238 Useful to generate playlists with absolute paths.
240 Note that the playlist sequence number must be unique for each segment
241 and it is not to be confused with the segment filename sequence number
242 which can be cyclic, for example if the @option{wrap} option is
251 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
255 Size cannot exceed 256 pixels in any dimension
258 Only BMP and PNG images can be stored
261 If a BMP image is used, it must be one of the following pixel formats:
263 BMP Bit Depth FFmpeg Pixel Format
273 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
276 If a PNG image is used, it must use the rgba pixel format
284 The image file muxer writes video frames to image files.
286 The output filenames are specified by a pattern, which can be used to
287 produce sequentially numbered series of files.
288 The pattern may contain the string "%d" or "%0@var{N}d", this string
289 specifies the position of the characters representing a numbering in
290 the filenames. If the form "%0@var{N}d" is used, the string
291 representing the number in each filename is 0-padded to @var{N}
292 digits. The literal character '%' can be specified in the pattern with
295 If the pattern contains "%d" or "%0@var{N}d", the first filename of
296 the file list specified will contain the number 1, all the following
297 numbers will be sequential.
299 The pattern may contain a suffix which is used to automatically
300 determine the format of the image files to write.
302 For example the pattern "img-%03d.bmp" will specify a sequence of
303 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
304 @file{img-010.bmp}, etc.
305 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
306 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
311 The following example shows how to use @command{ffmpeg} for creating a
312 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
313 taking one image every second from the input video:
315 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
318 Note that with @command{ffmpeg}, if the format is not specified with the
319 @code{-f} option and the output filename specifies an image file
320 format, the image2 muxer is automatically selected, so the previous
321 command can be written as:
323 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
326 Note also that the pattern must not necessarily contain "%d" or
327 "%0@var{N}d", for example to create a single image file
328 @file{img.jpeg} from the input video you can employ the command:
330 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
333 The @option{strftime} option allows you to expand the filename with
334 date and time information. Check the documentation of
335 the @code{strftime()} function for the syntax.
337 For example to generate image files from the @code{strftime()}
338 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
341 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
348 Start the sequence from the specified number. Default value is 1. Must
349 be a non-negative number.
352 If set to 1, the filename will always be interpreted as just a
353 filename, not a pattern, and the corresponding file will be continuously
354 overwritten with new images. Default value is 0.
357 If set to 1, expand the filename with date and time information from
358 @code{strftime()}. Default value is 0.
361 The image muxer supports the .Y.U.V image file format. This format is
362 special in that that each image frame consists of three files, for
363 each of the YUV420P components. To read or write this image file format,
364 specify the name of the '.Y' file. The muxer will automatically open the
365 '.U' and '.V' files as required.
369 Matroska container muxer.
371 This muxer implements the matroska and webm container specs.
375 The recognized metadata settings in this muxer are:
379 Set title name provided to a single track.
382 Specify the language of the track in the Matroska languages form.
384 The language can be either the 3 letters bibliographic ISO-639-2 (ISO
385 639-2/B) form (like "fre" for French), or a language code mixed with a
386 country code for specialities in languages (like "fre-ca" for Canadian
390 Set stereo 3D video layout of two views in a single video track.
392 The following values are recognized:
397 Both views are arranged side by side, Left-eye view is on the left
399 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
401 Both views are arranged in top-bottom orientation, Left-eye view is on top
402 @item checkerboard_rl
403 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
404 @item checkerboard_lr
405 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
406 @item row_interleaved_rl
407 Each view is constituted by a row based interleaving, Right-eye view is first row
408 @item row_interleaved_lr
409 Each view is constituted by a row based interleaving, Left-eye view is first row
410 @item col_interleaved_rl
411 Both views are arranged in a column based interleaving manner, Right-eye view is first column
412 @item col_interleaved_lr
413 Both views are arranged in a column based interleaving manner, Left-eye view is first column
414 @item anaglyph_cyan_red
415 All frames are in anaglyph format viewable through red-cyan filters
417 Both views are arranged side by side, Right-eye view is on the left
418 @item anaglyph_green_magenta
419 All frames are in anaglyph format viewable through green-magenta filters
421 Both eyes laced in one Block, Left-eye view is first
423 Both eyes laced in one Block, Right-eye view is first
427 For example a 3D WebM clip can be created using the following command line:
429 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
434 This muxer supports the following options:
437 @item reserve_index_space
438 By default, this muxer writes the index for seeking (called cues in Matroska
439 terms) at the end of the file, because it cannot know in advance how much space
440 to leave for the index at the beginning of the file. However for some use cases
441 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
442 index at the beginning of the file.
444 If this option is set to a non-zero value, the muxer will reserve a given amount
445 of space in the file header and then try to write the cues there when the muxing
446 finishes. If the available space does not suffice, muxing will fail. A safe size
447 for most use cases should be about 50kB per hour of video.
449 Note that cues are only written if the output is seekable and this option will
450 have no effect if it is not.
458 This muxer computes and prints the MD5 hash of all the input audio
459 and video frames. By default audio frames are converted to signed
460 16-bit raw audio and video frames to raw video before computing the
463 The output of the muxer consists of a single line of the form:
464 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
465 the computed MD5 hash.
467 For example to compute the MD5 hash of the input converted to raw
468 audio and video, and store it in the file @file{out.md5}:
470 ffmpeg -i INPUT -f md5 out.md5
473 You can print the MD5 to stdout with the command:
475 ffmpeg -i INPUT -f md5 -
478 See also the @ref{framemd5} muxer.
480 @section mov, mp4, ismv
482 MOV/MP4/ISMV (Smooth Streaming) muxer.
484 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
485 file has all the metadata about all packets stored in one location
486 (written at the end of the file, it can be moved to the start for
487 better playback by adding @var{faststart} to the @var{movflags}, or
488 using the @command{qt-faststart} tool). A fragmented
489 file consists of a number of fragments, where packets and metadata
490 about these packets are stored together. Writing a fragmented
491 file has the advantage that the file is decodable even if the
492 writing is interrupted (while a normal MOV/MP4 is undecodable if
493 it is not properly finished), and it requires less memory when writing
494 very long files (since writing normal MOV/MP4 files stores info about
495 every single packet in memory until the file is closed). The downside
496 is that it is less compatible with other applications.
500 Fragmentation is enabled by setting one of the AVOptions that define
501 how to cut the file into fragments:
504 @item -moov_size @var{bytes}
505 Reserves space for the moov atom at the beginning of the file instead of placing the
506 moov atom at the end. If the space reserved is insufficient, muxing will fail.
507 @item -movflags frag_keyframe
508 Start a new fragment at each video keyframe.
509 @item -frag_duration @var{duration}
510 Create fragments that are @var{duration} microseconds long.
511 @item -frag_size @var{size}
512 Create fragments that contain up to @var{size} bytes of payload data.
513 @item -movflags frag_custom
514 Allow the caller to manually choose when to cut fragments, by
515 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
516 the packets written so far. (This is only useful with other
517 applications integrating libavformat, not from @command{ffmpeg}.)
518 @item -min_frag_duration @var{duration}
519 Don't create fragments that are shorter than @var{duration} microseconds long.
522 If more than one condition is specified, fragments are cut when
523 one of the specified conditions is fulfilled. The exception to this is
524 @code{-min_frag_duration}, which has to be fulfilled for any of the other
527 Additionally, the way the output file is written can be adjusted
528 through a few other options:
531 @item -movflags empty_moov
532 Write an initial moov atom directly at the start of the file, without
533 describing any samples in it. Generally, an mdat/moov pair is written
534 at the start of the file, as a normal MOV/MP4 file, containing only
535 a short portion of the file. With this option set, there is no initial
536 mdat atom, and the moov atom only describes the tracks but has
539 Files written with this option set do not work in QuickTime.
540 This option is implicitly set when writing ismv (Smooth Streaming) files.
541 @item -movflags separate_moof
542 Write a separate moof (movie fragment) atom for each track. Normally,
543 packets for all tracks are written in a moof atom (which is slightly
544 more efficient), but with this option set, the muxer writes one moof/mdat
545 pair for each track, making it easier to separate tracks.
547 This option is implicitly set when writing ismv (Smooth Streaming) files.
548 @item -movflags faststart
549 Run a second pass moving the index (moov atom) to the beginning of the file.
550 This operation can take a while, and will not work in various situations such
551 as fragmented output, thus it is not enabled by default.
552 @item -movflags rtphint
553 Add RTP hinting tracks to the output file.
554 @item -movflags disable_chpl
555 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
556 and a QuickTime chapter track are written to the file. With this option
557 set, only the QuickTime chapter track will be written. Nero chapters can
558 cause failures when the file is reprocessed with certain tagging programs, like
559 mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
564 Smooth Streaming content can be pushed in real time to a publishing
565 point on IIS with this muxer. Example:
567 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
572 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
573 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
574 @code{id3v2_version} option controls which one is used. Setting
575 @code{id3v2_version} to 0 will disable the ID3v2 header completely. The legacy
576 ID3v1 tag is not written by default, but may be enabled with the
577 @code{write_id3v1} option.
579 The muxer may also write a Xing frame at the beginning, which contains the
580 number of frames in the file. It is useful for computing duration of VBR files.
581 The Xing frame is written if the output stream is seekable and if the
582 @code{write_xing} option is set to 1 (the default).
584 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
585 are supplied to the muxer in form of a video stream with a single packet. There
586 can be any number of those streams, each will correspond to a single APIC frame.
587 The stream metadata tags @var{title} and @var{comment} map to APIC
588 @var{description} and @var{picture type} respectively. See
589 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
591 Note that the APIC frames must be written at the beginning, so the muxer will
592 buffer the audio frames until it gets all the pictures. It is therefore advised
593 to provide the pictures as soon as possible to avoid excessive buffering.
597 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
599 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
602 To attach a picture to an mp3 file select both the audio and the picture stream
605 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
606 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
609 Write a "clean" MP3 without any extra features:
611 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
616 MPEG transport stream muxer.
618 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
620 The recognized metadata settings in mpegts muxer are @code{service_provider}
621 and @code{service_name}. If they are not set the default for
622 @code{service_provider} is "FFmpeg" and the default for
623 @code{service_name} is "Service01".
627 The muxer options are:
630 @item -mpegts_original_network_id @var{number}
631 Set the original_network_id (default 0x0001). This is unique identifier
632 of a network in DVB. Its main use is in the unique identification of a
633 service through the path Original_Network_ID, Transport_Stream_ID.
634 @item -mpegts_transport_stream_id @var{number}
635 Set the transport_stream_id (default 0x0001). This identifies a
637 @item -mpegts_service_id @var{number}
638 Set the service_id (default 0x0001) also known as program in DVB.
639 @item -mpegts_pmt_start_pid @var{number}
640 Set the first PID for PMT (default 0x1000, max 0x1f00).
641 @item -mpegts_start_pid @var{number}
642 Set the first PID for data packets (default 0x0100, max 0x0f00).
643 @item -mpegts_m2ts_mode @var{number}
644 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
645 @item -muxrate @var{number}
646 Set a constant muxrate (default VBR).
647 @item -pcr_period @var{numer}
648 Override the default PCR retransmission time (default 20ms), ignored
649 if variable muxrate is selected.
650 @item -pes_payload_size @var{number}
651 Set minimum PES packet payload in bytes.
652 @item -mpegts_flags @var{flags}
653 Set flags (see below).
654 @item -mpegts_copyts @var{number}
655 Preserve original timestamps, if value is set to 1. Default value is -1, which
656 results in shifting timestamps so that they start from 0.
657 @item -tables_version @var{number}
658 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
659 This option allows updating stream structure so that standard consumer may
660 detect the change. To do so, reopen output AVFormatContext (in case of API
661 usage) or restart ffmpeg instance, cyclically changing tables_version value:
663 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
664 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
666 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
667 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
668 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
673 Option mpegts_flags may take a set of such flags:
677 Reemit PAT/PMT before writing the next packet.
679 Use LATM packetization for AAC.
685 ffmpeg -i file.mpg -c copy \
686 -mpegts_original_network_id 0x1122 \
687 -mpegts_transport_stream_id 0x3344 \
688 -mpegts_service_id 0x5566 \
689 -mpegts_pmt_start_pid 0x1500 \
690 -mpegts_start_pid 0x150 \
691 -metadata service_provider="Some provider" \
692 -metadata service_name="Some Channel" \
700 This muxer does not generate any output file, it is mainly useful for
701 testing or benchmarking purposes.
703 For example to benchmark decoding with @command{ffmpeg} you can use the
706 ffmpeg -benchmark -i INPUT -f null out.null
709 Note that the above command does not read or write the @file{out.null}
710 file, but specifying the output file is required by the @command{ffmpeg}
713 Alternatively you can write the command as:
715 ffmpeg -benchmark -i INPUT -f null -
721 @item -syncpoints @var{flags}
722 Change the syncpoint usage in nut:
724 @item @var{default} use the normal low-overhead seeking aids.
725 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
726 Use of this option is not recommended, as the resulting files are very damage
727 sensitive and seeking is not possible. Also in general the overhead from
728 syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
729 all growing data tables, allowing to mux endless streams with limited memory
730 and wihout these disadvantages.
731 @item @var{timestamped} extend the syncpoint with a wallclock field.
733 The @var{none} and @var{timestamped} flags are experimental.
734 @item -write_index @var{bool}
735 Write index at the end, the default is to write an index.
739 ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
747 @item -page_duration @var{duration}
748 Preferred page duration, in microseconds. The muxer will attempt to create
749 pages that are approximately @var{duration} microseconds long. This allows the
750 user to compromise between seek granularity and container overhead. The default
751 is 1 second. A value of 0 will fill all segments, making pages as large as
752 possible. A value of 1 will effectively use 1 packet-per-page in most
753 situations, giving a small seek granularity at the cost of additional container
758 @section segment, stream_segment, ssegment
760 Basic stream segmenter.
762 This muxer outputs streams to a number of separate files of nearly
763 fixed duration. Output filename pattern can be set in a fashion similar to
766 @code{stream_segment} is a variant of the muxer used to write to
767 streaming output formats, i.e. which do not require global headers,
768 and is recommended for outputting e.g. to MPEG transport stream segments.
769 @code{ssegment} is a shorter alias for @code{stream_segment}.
771 Every segment starts with a keyframe of the selected reference stream,
772 which is set through the @option{reference_stream} option.
774 Note that if you want accurate splitting for a video file, you need to
775 make the input key frames correspond to the exact splitting times
776 expected by the segmenter, or the segment muxer will start the new
777 segment with the key frame found next after the specified start
780 The segment muxer works best with a single constant frame rate video.
782 Optionally it can generate a list of the created segments, by setting
783 the option @var{segment_list}. The list type is specified by the
784 @var{segment_list_type} option. The entry filenames in the segment
785 list are set by default to the basename of the corresponding segment
788 See also the @ref{hls} muxer, which provides a more specific
789 implementation for HLS segmentation.
793 The segment muxer supports the following options:
796 @item reference_stream @var{specifier}
797 Set the reference stream, as specified by the string @var{specifier}.
798 If @var{specifier} is set to @code{auto}, the reference is chosen
799 automatically. Otherwise it must be a stream specifier (see the ``Stream
800 specifiers'' chapter in the ffmpeg manual) which specifies the
801 reference stream. The default value is @code{auto}.
803 @item segment_format @var{format}
804 Override the inner container format, by default it is guessed by the filename
807 @item segment_list @var{name}
808 Generate also a listfile named @var{name}. If not specified no
809 listfile is generated.
811 @item segment_list_flags @var{flags}
812 Set flags affecting the segment list generation.
814 It currently supports the following flags:
817 Allow caching (only affects M3U8 list files).
820 Allow live-friendly file generation.
823 @item segment_list_type @var{type}
824 Select the listing format.
826 @item @var{flat} use a simple flat list of entries.
827 @item @var{hls} use a m3u8-like structure.
830 @item segment_list_size @var{size}
831 Update the list file so that it contains at most @var{size}
832 segments. If 0 the list file will contain all the segments. Default
835 @item segment_list_entry_prefix @var{prefix}
836 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
837 By default no prefix is applied.
839 The following values are recognized:
842 Generate a flat list for the created segments, one segment per line.
845 Generate a list for the created segments, one segment per line,
846 each line matching the format (comma-separated values):
848 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
851 @var{segment_filename} is the name of the output file generated by the
852 muxer according to the provided pattern. CSV escaping (according to
853 RFC4180) is applied if required.
855 @var{segment_start_time} and @var{segment_end_time} specify
856 the segment start and end time expressed in seconds.
858 A list file with the suffix @code{".csv"} or @code{".ext"} will
859 auto-select this format.
861 @samp{ext} is deprecated in favor or @samp{csv}.
864 Generate an ffconcat file for the created segments. The resulting file
865 can be read using the FFmpeg @ref{concat} demuxer.
867 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
868 auto-select this format.
871 Generate an extended M3U8 file, version 3, compliant with
872 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
874 A list file with the suffix @code{".m3u8"} will auto-select this format.
877 If not specified the type is guessed from the list file name suffix.
879 @item segment_time @var{time}
880 Set segment duration to @var{time}, the value must be a duration
881 specification. Default value is "2". See also the
882 @option{segment_times} option.
884 Note that splitting may not be accurate, unless you force the
885 reference stream key-frames at the given time. See the introductory
886 notice and the examples below.
888 @item segment_atclocktime @var{1|0}
889 If set to "1" split at regular clock time intervals starting from 00:00
890 o'clock. The @var{time} value specified in @option{segment_time} is
891 used for setting the length of the splitting interval.
893 For example with @option{segment_time} set to "900" this makes it possible
894 to create files at 12:00 o'clock, 12:15, 12:30, etc.
896 Default value is "0".
898 @item segment_time_delta @var{delta}
899 Specify the accuracy time when selecting the start time for a
900 segment, expressed as a duration specification. Default value is "0".
902 When delta is specified a key-frame will start a new segment if its
903 PTS satisfies the relation:
905 PTS >= start_time - time_delta
908 This option is useful when splitting video content, which is always
909 split at GOP boundaries, in case a key frame is found just before the
910 specified split time.
912 In particular may be used in combination with the @file{ffmpeg} option
913 @var{force_key_frames}. The key frame times specified by
914 @var{force_key_frames} may not be set accurately because of rounding
915 issues, with the consequence that a key frame time may result set just
916 before the specified time. For constant frame rate videos a value of
917 1/(2*@var{frame_rate}) should address the worst case mismatch between
918 the specified time and the time set by @var{force_key_frames}.
920 @item segment_times @var{times}
921 Specify a list of split points. @var{times} contains a list of comma
922 separated duration specifications, in increasing order. See also
923 the @option{segment_time} option.
925 @item segment_frames @var{frames}
926 Specify a list of split video frame numbers. @var{frames} contains a
927 list of comma separated integer numbers, in increasing order.
929 This option specifies to start a new segment whenever a reference
930 stream key frame is found and the sequential number (starting from 0)
931 of the frame is greater or equal to the next value in the list.
933 @item segment_wrap @var{limit}
934 Wrap around segment index once it reaches @var{limit}.
936 @item segment_start_number @var{number}
937 Set the sequence number of the first segment. Defaults to @code{0}.
939 @item reset_timestamps @var{1|0}
940 Reset timestamps at the begin of each segment, so that each segment
941 will start with near-zero timestamps. It is meant to ease the playback
942 of the generated segments. May not work with some combinations of
943 muxers/codecs. It is set to @code{0} by default.
945 @item initial_offset @var{offset}
946 Specify timestamp offset to apply to the output packet timestamps. The
947 argument must be a time duration specification, and defaults to 0.
954 To remux the content of file @file{in.mkv} to a list of segments
955 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
956 generated segments to @file{out.list}:
958 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
962 As the example above, but segment the input file according to the split
963 points specified by the @var{segment_times} option:
965 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
969 As the example above, but use the @command{ffmpeg} @option{force_key_frames}
970 option to force key frames in the input at the specified location, together
971 with the segment option @option{segment_time_delta} to account for
972 possible roundings operated when setting key frame times.
974 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
975 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
977 In order to force key frames on the input file, transcoding is
981 Segment the input file by splitting the input file according to the
982 frame numbers sequence specified with the @option{segment_frames} option:
984 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
988 To convert the @file{in.mkv} to TS segments using the @code{libx264}
989 and @code{libfaac} encoders:
991 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
995 Segment the input file, and create an M3U8 live playlist (can be used
998 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
999 -segment_list_flags +live -segment_time 10 out%03d.mkv
1003 @section smoothstreaming
1005 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
1009 Specify the number of fragments kept in the manifest. Default 0 (keep all).
1011 @item extra_window_size
1012 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
1014 @item lookahead_count
1015 Specify the number of lookahead fragments. Default 2.
1017 @item min_frag_duration
1018 Specify the minimum fragment duration (in microseconds). Default 5000000.
1020 @item remove_at_exit
1021 Specify whether to remove all fragments when finished. Default 0 (do not remove).
1027 The tee muxer can be used to write the same data to several files or any
1028 other kind of muxer. It can be used, for example, to both stream a video to
1029 the network and save it to disk at the same time.
1031 It is different from specifying several outputs to the @command{ffmpeg}
1032 command-line tool because the audio and video data will be encoded only once
1033 with the tee muxer; encoding can be a very expensive process. It is not
1034 useful when using the libavformat API directly because it is then possible
1035 to feed the same packets to several muxers directly.
1037 The slave outputs are specified in the file name given to the muxer,
1038 separated by '|'. If any of the slave name contains the '|' separator,
1039 leading or trailing spaces or any special character, it must be
1040 escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
1041 section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
1043 Muxer options can be specified for each slave by prepending them as a list of
1044 @var{key}=@var{value} pairs separated by ':', between square brackets. If
1045 the options values contain a special character or the ':' separator, they
1046 must be escaped; note that this is a second level escaping.
1048 The following special options are also recognized:
1051 Specify the format name. Useful if it cannot be guessed from the
1054 @item bsfs[/@var{spec}]
1055 Specify a list of bitstream filters to apply to the specified
1058 It is possible to specify to which streams a given bitstream filter
1059 applies, by appending a stream specifier to the option separated by
1060 @code{/}. @var{spec} must be a stream specifier (see @ref{Format
1061 stream specifiers}). If the stream specifier is not specified, the
1062 bitstream filters will be applied to all streams in the output.
1064 Several bitstream filters can be specified, separated by ",".
1067 Select the streams that should be mapped to the slave output,
1068 specified by a stream specifier. If not specified, this defaults to
1069 all the input streams.
1072 @subsection Examples
1076 Encode something and both archive it in a WebM file and stream it
1077 as MPEG-TS over UDP (the streams need to be explicitly mapped):
1079 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
1080 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
1084 Use @command{ffmpeg} to encode the input, and send the output
1085 to three different destinations. The @code{dump_extra} bitstream
1086 filter is used to add extradata information to all the output video
1087 keyframes packets, as requested by the MPEG-TS format. The select
1088 option is applied to @file{out.aac} in order to make it contain only
1091 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1092 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
1096 As below, but select only stream @code{a:1} for the audio output. Note
1097 that a second level escaping must be performed, as ":" is a special
1098 character used to separate options.
1100 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1101 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
1105 Note: some codecs may need different options depending on the output format;
1106 the auto-detection of this can not work with the tee muxer. The main example
1107 is the @option{global_header} flag.
1109 @section webm_dash_manifest
1111 WebM DASH Manifest muxer.
1113 This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
1117 This muxer supports the following options:
1120 @item adaptation_sets
1121 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
1122 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
1123 audio and video streams. Any number of adaptation sets can be added using this option.
1128 ffmpeg -f webm_dash_manifest -i video1.webm \
1129 -f webm_dash_manifest -i video2.webm \
1130 -f webm_dash_manifest -i audio1.webm \
1131 -f webm_dash_manifest -i audio2.webm \
1132 -map 0 -map 1 -map 2 -map 3 \
1134 -f webm_dash_manifest \
1135 -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \