4 Muxers are configured elements in FFmpeg which allow writing
5 multimedia streams to a particular type of file.
7 When you configure your FFmpeg build, all the supported muxers
8 are enabled by default. You can list all available muxers using the
9 configure option @code{--list-muxers}.
11 You can disable all the muxers with the configure option
12 @code{--disable-muxers} and selectively enable / disable single muxers
13 with the options @code{--enable-muxer=@var{MUXER}} /
14 @code{--disable-muxer=@var{MUXER}}.
16 The option @code{-formats} of the ff* tools will display the list of
19 A description of some of the currently available muxers follows.
24 Audio Interchange File Format muxer.
28 It accepts the following options:
32 Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).
35 Select ID3v2 version to write. Currently only version 3 and 4 (aka.
36 ID3v2.3 and ID3v2.4) are supported. The default is version 4.
43 CRC (Cyclic Redundancy Check) testing format.
45 This muxer computes and prints the Adler-32 CRC of all the input audio
46 and video frames. By default audio frames are converted to signed
47 16-bit raw audio and video frames to raw video before computing the
50 The output of the muxer consists of a single line of the form:
51 CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
52 8 digits containing the CRC for all the decoded input frames.
54 See also the @ref{framecrc} muxer.
58 For example to compute the CRC of the input, and store it in the file
61 ffmpeg -i INPUT -f crc out.crc
64 You can print the CRC to stdout with the command:
66 ffmpeg -i INPUT -f crc -
69 You can select the output format of each frame with @command{ffmpeg} by
70 specifying the audio and video codec and format. For example to
71 compute the CRC of the input audio converted to PCM unsigned 8-bit
72 and the input video converted to MPEG-2 video, use the command:
74 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
80 Per-packet CRC (Cyclic Redundancy Check) testing format.
82 This muxer computes and prints the Adler-32 CRC for each audio
83 and video packet. By default audio frames are converted to signed
84 16-bit raw audio and video frames to raw video before computing the
87 The output of the muxer consists of a line for each audio and video
90 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
93 @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
98 For example to compute the CRC of the audio and video frames in
99 @file{INPUT}, converted to raw audio and video packets, and store it
100 in the file @file{out.crc}:
102 ffmpeg -i INPUT -f framecrc out.crc
105 To print the information to stdout, use the command:
107 ffmpeg -i INPUT -f framecrc -
110 With @command{ffmpeg}, you can select the output format to which the
111 audio and video frames are encoded before computing the CRC for each
112 packet by specifying the audio and video codec. For example, to
113 compute the CRC of each decoded input audio frame converted to PCM
114 unsigned 8-bit and of each decoded input video frame converted to
115 MPEG-2 video, use the command:
117 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
120 See also the @ref{crc} muxer.
125 Per-packet MD5 testing format.
127 This muxer computes and prints the MD5 hash for each audio
128 and video packet. By default audio frames are converted to signed
129 16-bit raw audio and video frames to raw video before computing the
132 The output of the muxer consists of a line for each audio and video
135 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
138 @var{MD5} is a hexadecimal number representing the computed MD5 hash
143 For example to compute the MD5 of the audio and video frames in
144 @file{INPUT}, converted to raw audio and video packets, and store it
145 in the file @file{out.md5}:
147 ffmpeg -i INPUT -f framemd5 out.md5
150 To print the information to stdout, use the command:
152 ffmpeg -i INPUT -f framemd5 -
155 See also the @ref{md5} muxer.
162 It accepts the following options:
166 Set the number of times to loop the output. Use @code{-1} for no loop, @code{0}
167 for looping indefinitely (default).
170 Force the delay (expressed in centiseconds) after the last frame. Each frame
171 ends with a delay until the next frame. The default is @code{-1}, which is a
172 special value to tell the muxer to re-use the previous delay. In case of a
173 loop, you might want to customize this value to mark a pause for instance.
176 For example, to encode a gif looping 10 times, with a 5 seconds delay between
179 ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif
182 Note 1: if you wish to extract the frames in separate GIF files, you need to
183 force the @ref{image2} muxer:
185 ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"
188 Note 2: the GIF format has a very small time base: the delay between two frames
189 can not be smaller than one centi second.
194 Apple HTTP Live Streaming muxer that segments MPEG-TS according to
195 the HTTP Live Streaming (HLS) specification.
197 It creates a playlist file, and one or more segment files. The output filename
198 specifies the playlist filename.
200 By default, the muxer creates a file for each segment produced. These files
201 have the same name as the playlist, followed by a sequential number and a
204 For example, to convert an input file with @command{ffmpeg}:
206 ffmpeg -i in.nut out.m3u8
208 This example will produce the playlist, @file{out.m3u8}, and segment files:
209 @file{out0.ts}, @file{out1.ts}, @file{out2.ts}, etc.
211 See also the @ref{segment} muxer, which provides a more generic and
212 flexible implementation of a segmenter, and can be used to perform HLS
217 This muxer supports the following options:
220 @item hls_time @var{seconds}
221 Set the segment length in seconds. Default value is 2.
223 @item hls_list_size @var{size}
224 Set the maximum number of playlist entries. If set to 0 the list file
225 will contain all the segments. Default value is 5.
227 @item hls_ts_options @var{options_list}
228 Set output format options using a :-separated list of key=value
229 parameters. Values containing @code{:} special characters must be
232 @item hls_wrap @var{wrap}
233 Set the number after which the segment filename number (the number
234 specified in each segment file) wraps. If set to 0 the number will be
235 never wrapped. Default value is 0.
237 This option is useful to avoid to fill the disk with many segment
238 files, and limits the maximum number of segment files written to disk
241 @item start_number @var{number}
242 Start the playlist sequence number from @var{number}. Default value is
245 @item hls_allow_cache @var{allowcache}
246 Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments.
248 @item hls_base_url @var{baseurl}
249 Append @var{baseurl} to every entry in the playlist.
250 Useful to generate playlists with absolute paths.
252 Note that the playlist sequence number must be unique for each segment
253 and it is not to be confused with the segment filename sequence number
254 which can be cyclic, for example if the @option{wrap} option is
257 @item hls_segment_filename @var{filename}
258 Set the segment filename. Unless hls_flags single_file is set @var{filename}
259 is used as a string format with the segment number:
261 ffmpeg in.nut -hls_segment_filename 'file%03d.ts' out.m3u8
263 This example will produce the playlist, @file{out.m3u8}, and segment files:
264 @file{file000.ts}, @file{file001.ts}, @file{file002.ts}, etc.
266 @item hls_flags single_file
267 If this flag is set, the muxer will store all segments in a single MPEG-TS
268 file, and will use byte ranges in the playlist. HLS playlists generated with
269 this way will have the version number 4.
272 ffmpeg -i in.nut -hls_flags single_file out.m3u8
274 Will produce the playlist, @file{out.m3u8}, and a single segment file,
277 @item hls_flags delete_segments
278 Segment files removed from the playlist are deleted after a period of time
279 equal to the duration of the segment plus the duration of the playlist.
287 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
291 Size cannot exceed 256 pixels in any dimension
294 Only BMP and PNG images can be stored
297 If a BMP image is used, it must be one of the following pixel formats:
299 BMP Bit Depth FFmpeg Pixel Format
309 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
312 If a PNG image is used, it must use the rgba pixel format
320 The image file muxer writes video frames to image files.
322 The output filenames are specified by a pattern, which can be used to
323 produce sequentially numbered series of files.
324 The pattern may contain the string "%d" or "%0@var{N}d", this string
325 specifies the position of the characters representing a numbering in
326 the filenames. If the form "%0@var{N}d" is used, the string
327 representing the number in each filename is 0-padded to @var{N}
328 digits. The literal character '%' can be specified in the pattern with
331 If the pattern contains "%d" or "%0@var{N}d", the first filename of
332 the file list specified will contain the number 1, all the following
333 numbers will be sequential.
335 The pattern may contain a suffix which is used to automatically
336 determine the format of the image files to write.
338 For example the pattern "img-%03d.bmp" will specify a sequence of
339 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
340 @file{img-010.bmp}, etc.
341 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
342 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
347 The following example shows how to use @command{ffmpeg} for creating a
348 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
349 taking one image every second from the input video:
351 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
354 Note that with @command{ffmpeg}, if the format is not specified with the
355 @code{-f} option and the output filename specifies an image file
356 format, the image2 muxer is automatically selected, so the previous
357 command can be written as:
359 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
362 Note also that the pattern must not necessarily contain "%d" or
363 "%0@var{N}d", for example to create a single image file
364 @file{img.jpeg} from the input video you can employ the command:
366 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
369 The @option{strftime} option allows you to expand the filename with
370 date and time information. Check the documentation of
371 the @code{strftime()} function for the syntax.
373 For example to generate image files from the @code{strftime()}
374 "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
377 ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
384 Start the sequence from the specified number. Default value is 1. Must
385 be a non-negative number.
388 If set to 1, the filename will always be interpreted as just a
389 filename, not a pattern, and the corresponding file will be continuously
390 overwritten with new images. Default value is 0.
393 If set to 1, expand the filename with date and time information from
394 @code{strftime()}. Default value is 0.
397 The image muxer supports the .Y.U.V image file format. This format is
398 special in that that each image frame consists of three files, for
399 each of the YUV420P components. To read or write this image file format,
400 specify the name of the '.Y' file. The muxer will automatically open the
401 '.U' and '.V' files as required.
405 Matroska container muxer.
407 This muxer implements the matroska and webm container specs.
411 The recognized metadata settings in this muxer are:
415 Set title name provided to a single track.
418 Specify the language of the track in the Matroska languages form.
420 The language can be either the 3 letters bibliographic ISO-639-2 (ISO
421 639-2/B) form (like "fre" for French), or a language code mixed with a
422 country code for specialities in languages (like "fre-ca" for Canadian
426 Set stereo 3D video layout of two views in a single video track.
428 The following values are recognized:
433 Both views are arranged side by side, Left-eye view is on the left
435 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
437 Both views are arranged in top-bottom orientation, Left-eye view is on top
438 @item checkerboard_rl
439 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
440 @item checkerboard_lr
441 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
442 @item row_interleaved_rl
443 Each view is constituted by a row based interleaving, Right-eye view is first row
444 @item row_interleaved_lr
445 Each view is constituted by a row based interleaving, Left-eye view is first row
446 @item col_interleaved_rl
447 Both views are arranged in a column based interleaving manner, Right-eye view is first column
448 @item col_interleaved_lr
449 Both views are arranged in a column based interleaving manner, Left-eye view is first column
450 @item anaglyph_cyan_red
451 All frames are in anaglyph format viewable through red-cyan filters
453 Both views are arranged side by side, Right-eye view is on the left
454 @item anaglyph_green_magenta
455 All frames are in anaglyph format viewable through green-magenta filters
457 Both eyes laced in one Block, Left-eye view is first
459 Both eyes laced in one Block, Right-eye view is first
463 For example a 3D WebM clip can be created using the following command line:
465 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
470 This muxer supports the following options:
473 @item reserve_index_space
474 By default, this muxer writes the index for seeking (called cues in Matroska
475 terms) at the end of the file, because it cannot know in advance how much space
476 to leave for the index at the beginning of the file. However for some use cases
477 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
478 index at the beginning of the file.
480 If this option is set to a non-zero value, the muxer will reserve a given amount
481 of space in the file header and then try to write the cues there when the muxing
482 finishes. If the available space does not suffice, muxing will fail. A safe size
483 for most use cases should be about 50kB per hour of video.
485 Note that cues are only written if the output is seekable and this option will
486 have no effect if it is not.
494 This muxer computes and prints the MD5 hash of all the input audio
495 and video frames. By default audio frames are converted to signed
496 16-bit raw audio and video frames to raw video before computing the
499 The output of the muxer consists of a single line of the form:
500 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
501 the computed MD5 hash.
503 For example to compute the MD5 hash of the input converted to raw
504 audio and video, and store it in the file @file{out.md5}:
506 ffmpeg -i INPUT -f md5 out.md5
509 You can print the MD5 to stdout with the command:
511 ffmpeg -i INPUT -f md5 -
514 See also the @ref{framemd5} muxer.
516 @section mov, mp4, ismv
518 MOV/MP4/ISMV (Smooth Streaming) muxer.
520 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
521 file has all the metadata about all packets stored in one location
522 (written at the end of the file, it can be moved to the start for
523 better playback by adding @var{faststart} to the @var{movflags}, or
524 using the @command{qt-faststart} tool). A fragmented
525 file consists of a number of fragments, where packets and metadata
526 about these packets are stored together. Writing a fragmented
527 file has the advantage that the file is decodable even if the
528 writing is interrupted (while a normal MOV/MP4 is undecodable if
529 it is not properly finished), and it requires less memory when writing
530 very long files (since writing normal MOV/MP4 files stores info about
531 every single packet in memory until the file is closed). The downside
532 is that it is less compatible with other applications.
536 Fragmentation is enabled by setting one of the AVOptions that define
537 how to cut the file into fragments:
540 @item -moov_size @var{bytes}
541 Reserves space for the moov atom at the beginning of the file instead of placing the
542 moov atom at the end. If the space reserved is insufficient, muxing will fail.
543 @item -movflags frag_keyframe
544 Start a new fragment at each video keyframe.
545 @item -frag_duration @var{duration}
546 Create fragments that are @var{duration} microseconds long.
547 @item -frag_size @var{size}
548 Create fragments that contain up to @var{size} bytes of payload data.
549 @item -movflags frag_custom
550 Allow the caller to manually choose when to cut fragments, by
551 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
552 the packets written so far. (This is only useful with other
553 applications integrating libavformat, not from @command{ffmpeg}.)
554 @item -min_frag_duration @var{duration}
555 Don't create fragments that are shorter than @var{duration} microseconds long.
558 If more than one condition is specified, fragments are cut when
559 one of the specified conditions is fulfilled. The exception to this is
560 @code{-min_frag_duration}, which has to be fulfilled for any of the other
563 Additionally, the way the output file is written can be adjusted
564 through a few other options:
567 @item -movflags empty_moov
568 Write an initial moov atom directly at the start of the file, without
569 describing any samples in it. Generally, an mdat/moov pair is written
570 at the start of the file, as a normal MOV/MP4 file, containing only
571 a short portion of the file. With this option set, there is no initial
572 mdat atom, and the moov atom only describes the tracks but has
575 This option is implicitly set when writing ismv (Smooth Streaming) files.
576 @item -movflags separate_moof
577 Write a separate moof (movie fragment) atom for each track. Normally,
578 packets for all tracks are written in a moof atom (which is slightly
579 more efficient), but with this option set, the muxer writes one moof/mdat
580 pair for each track, making it easier to separate tracks.
582 This option is implicitly set when writing ismv (Smooth Streaming) files.
583 @item -movflags faststart
584 Run a second pass moving the index (moov atom) to the beginning of the file.
585 This operation can take a while, and will not work in various situations such
586 as fragmented output, thus it is not enabled by default.
587 @item -movflags rtphint
588 Add RTP hinting tracks to the output file.
589 @item -movflags disable_chpl
590 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
591 and a QuickTime chapter track are written to the file. With this option
592 set, only the QuickTime chapter track will be written. Nero chapters can
593 cause failures when the file is reprocessed with certain tagging programs, like
594 mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
595 @item -movflags omit_tfhd_offset
596 Do not write any absolute base_data_offset in tfhd atoms. This avoids
597 tying fragments to absolute byte positions in the file/streams.
598 @item -movflags default_base_moof
599 Similarly to the omit_tfhd_offset, this flag avoids writing the
600 absolute base_data_offset field in tfhd atoms, but does so by using
601 the new default-base-is-moof flag instead. This flag is new from
602 14496-12:2012. This may make the fragments easier to parse in certain
603 circumstances (avoiding basing track fragment location calculations
604 on the implicit end of the previous track fragment).
609 Smooth Streaming content can be pushed in real time to a publishing
610 point on IIS with this muxer. Example:
612 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
617 The MP3 muxer writes a raw MP3 stream with the following optional features:
620 An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
621 2.4 are supported, the @code{id3v2_version} private option controls which one is
622 used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header
625 The muxer supports writing attached pictures (APIC frames) to the ID3v2 header.
626 The pictures are supplied to the muxer in form of a video stream with a single
627 packet. There can be any number of those streams, each will correspond to a
628 single APIC frame. The stream metadata tags @var{title} and @var{comment} map
629 to APIC @var{description} and @var{picture type} respectively. See
630 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
632 Note that the APIC frames must be written at the beginning, so the muxer will
633 buffer the audio frames until it gets all the pictures. It is therefore advised
634 to provide the pictures as soon as possible to avoid excessive buffering.
637 A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
638 default, but will be written only if the output is seekable. The
639 @code{write_xing} private option can be used to disable it. The frame contains
640 various information that may be useful to the decoder, like the audio duration
644 A legacy ID3v1 tag at the end of the file (disabled by default). It may be
645 enabled with the @code{write_id3v1} private option, but as its capabilities are
646 very limited, its usage is not recommended.
651 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
653 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
656 To attach a picture to an mp3 file select both the audio and the picture stream
659 ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
660 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
663 Write a "clean" MP3 without any extra features:
665 ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
670 MPEG transport stream muxer.
672 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
674 The recognized metadata settings in mpegts muxer are @code{service_provider}
675 and @code{service_name}. If they are not set the default for
676 @code{service_provider} is "FFmpeg" and the default for
677 @code{service_name} is "Service01".
681 The muxer options are:
684 @item -mpegts_original_network_id @var{number}
685 Set the original_network_id (default 0x0001). This is unique identifier
686 of a network in DVB. Its main use is in the unique identification of a
687 service through the path Original_Network_ID, Transport_Stream_ID.
688 @item -mpegts_transport_stream_id @var{number}
689 Set the transport_stream_id (default 0x0001). This identifies a
691 @item -mpegts_service_id @var{number}
692 Set the service_id (default 0x0001) also known as program in DVB.
693 @item -mpegts_service_type @var{number}
694 Set the program service_type (default @var{digital_tv}), see below
695 a list of pre defined values.
696 @item -mpegts_pmt_start_pid @var{number}
697 Set the first PID for PMT (default 0x1000, max 0x1f00).
698 @item -mpegts_start_pid @var{number}
699 Set the first PID for data packets (default 0x0100, max 0x0f00).
700 @item -mpegts_m2ts_mode @var{number}
701 Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.
702 @item -muxrate @var{number}
703 Set a constant muxrate (default VBR).
704 @item -pcr_period @var{numer}
705 Override the default PCR retransmission time (default 20ms), ignored
706 if variable muxrate is selected.
707 @item -pes_payload_size @var{number}
708 Set minimum PES packet payload in bytes.
709 @item -mpegts_flags @var{flags}
710 Set flags (see below).
711 @item -mpegts_copyts @var{number}
712 Preserve original timestamps, if value is set to 1. Default value is -1, which
713 results in shifting timestamps so that they start from 0.
714 @item -tables_version @var{number}
715 Set PAT, PMT and SDT version (default 0, valid values are from 0 to 31, inclusively).
716 This option allows updating stream structure so that standard consumer may
717 detect the change. To do so, reopen output AVFormatContext (in case of API
718 usage) or restart ffmpeg instance, cyclically changing tables_version value:
720 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
721 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
723 ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
724 ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
725 ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
730 Option mpegts_service_type accepts the following values:
734 Any hexdecimal value between 0x01 to 0xff as defined in ETSI 300 468.
738 Digital Radio service.
741 @item advanced_codec_digital_radio
742 Advanced Codec Digital Radio service.
743 @item mpeg2_digital_hdtv
744 MPEG2 Digital HDTV service.
745 @item advanced_codec_digital_sdtv
746 Advanced Codec Digital SDTV service.
747 @item advanced_codec_digital_hdtv
748 Advanced Codec Digital HDTV service.
751 Option mpegts_flags may take a set of such flags:
755 Reemit PAT/PMT before writing the next packet.
757 Use LATM packetization for AAC.
763 ffmpeg -i file.mpg -c copy \
764 -mpegts_original_network_id 0x1122 \
765 -mpegts_transport_stream_id 0x3344 \
766 -mpegts_service_id 0x5566 \
767 -mpegts_pmt_start_pid 0x1500 \
768 -mpegts_start_pid 0x150 \
769 -metadata service_provider="Some provider" \
770 -metadata service_name="Some Channel" \
778 This muxer does not generate any output file, it is mainly useful for
779 testing or benchmarking purposes.
781 For example to benchmark decoding with @command{ffmpeg} you can use the
784 ffmpeg -benchmark -i INPUT -f null out.null
787 Note that the above command does not read or write the @file{out.null}
788 file, but specifying the output file is required by the @command{ffmpeg}
791 Alternatively you can write the command as:
793 ffmpeg -benchmark -i INPUT -f null -
799 @item -syncpoints @var{flags}
800 Change the syncpoint usage in nut:
802 @item @var{default} use the normal low-overhead seeking aids.
803 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
804 Use of this option is not recommended, as the resulting files are very damage
805 sensitive and seeking is not possible. Also in general the overhead from
806 syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
807 all growing data tables, allowing to mux endless streams with limited memory
808 and without these disadvantages.
809 @item @var{timestamped} extend the syncpoint with a wallclock field.
811 The @var{none} and @var{timestamped} flags are experimental.
812 @item -write_index @var{bool}
813 Write index at the end, the default is to write an index.
817 ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
825 @item -page_duration @var{duration}
826 Preferred page duration, in microseconds. The muxer will attempt to create
827 pages that are approximately @var{duration} microseconds long. This allows the
828 user to compromise between seek granularity and container overhead. The default
829 is 1 second. A value of 0 will fill all segments, making pages as large as
830 possible. A value of 1 will effectively use 1 packet-per-page in most
831 situations, giving a small seek granularity at the cost of additional container
833 @item -serial_offset @var{value}
834 Serial value from which to set the streams serial number.
835 Setting it to different and sufficiently large values ensures that the produced
836 ogg files can be safely chained.
841 @section segment, stream_segment, ssegment
843 Basic stream segmenter.
845 This muxer outputs streams to a number of separate files of nearly
846 fixed duration. Output filename pattern can be set in a fashion
847 similar to @ref{image2}, or by using a @code{strftime} template if
848 the @option{strftime} option is enabled.
850 @code{stream_segment} is a variant of the muxer used to write to
851 streaming output formats, i.e. which do not require global headers,
852 and is recommended for outputting e.g. to MPEG transport stream segments.
853 @code{ssegment} is a shorter alias for @code{stream_segment}.
855 Every segment starts with a keyframe of the selected reference stream,
856 which is set through the @option{reference_stream} option.
858 Note that if you want accurate splitting for a video file, you need to
859 make the input key frames correspond to the exact splitting times
860 expected by the segmenter, or the segment muxer will start the new
861 segment with the key frame found next after the specified start
864 The segment muxer works best with a single constant frame rate video.
866 Optionally it can generate a list of the created segments, by setting
867 the option @var{segment_list}. The list type is specified by the
868 @var{segment_list_type} option. The entry filenames in the segment
869 list are set by default to the basename of the corresponding segment
872 See also the @ref{hls} muxer, which provides a more specific
873 implementation for HLS segmentation.
877 The segment muxer supports the following options:
880 @item reference_stream @var{specifier}
881 Set the reference stream, as specified by the string @var{specifier}.
882 If @var{specifier} is set to @code{auto}, the reference is chosen
883 automatically. Otherwise it must be a stream specifier (see the ``Stream
884 specifiers'' chapter in the ffmpeg manual) which specifies the
885 reference stream. The default value is @code{auto}.
887 @item segment_format @var{format}
888 Override the inner container format, by default it is guessed by the filename
891 @item segment_format_options @var{options_list}
892 Set output format options using a :-separated list of key=value
893 parameters. Values containing the @code{:} special character must be
896 @item segment_list @var{name}
897 Generate also a listfile named @var{name}. If not specified no
898 listfile is generated.
900 @item segment_list_flags @var{flags}
901 Set flags affecting the segment list generation.
903 It currently supports the following flags:
906 Allow caching (only affects M3U8 list files).
909 Allow live-friendly file generation.
912 @item segment_list_type @var{type}
913 Select the listing format.
915 @item @var{flat} use a simple flat list of entries.
916 @item @var{hls} use a m3u8-like structure.
919 @item segment_list_size @var{size}
920 Update the list file so that it contains at most @var{size}
921 segments. If 0 the list file will contain all the segments. Default
924 @item segment_list_entry_prefix @var{prefix}
925 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
926 By default no prefix is applied.
928 The following values are recognized:
931 Generate a flat list for the created segments, one segment per line.
934 Generate a list for the created segments, one segment per line,
935 each line matching the format (comma-separated values):
937 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
940 @var{segment_filename} is the name of the output file generated by the
941 muxer according to the provided pattern. CSV escaping (according to
942 RFC4180) is applied if required.
944 @var{segment_start_time} and @var{segment_end_time} specify
945 the segment start and end time expressed in seconds.
947 A list file with the suffix @code{".csv"} or @code{".ext"} will
948 auto-select this format.
950 @samp{ext} is deprecated in favor or @samp{csv}.
953 Generate an ffconcat file for the created segments. The resulting file
954 can be read using the FFmpeg @ref{concat} demuxer.
956 A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
957 auto-select this format.
960 Generate an extended M3U8 file, version 3, compliant with
961 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
963 A list file with the suffix @code{".m3u8"} will auto-select this format.
966 If not specified the type is guessed from the list file name suffix.
968 @item segment_time @var{time}
969 Set segment duration to @var{time}, the value must be a duration
970 specification. Default value is "2". See also the
971 @option{segment_times} option.
973 Note that splitting may not be accurate, unless you force the
974 reference stream key-frames at the given time. See the introductory
975 notice and the examples below.
977 @item segment_atclocktime @var{1|0}
978 If set to "1" split at regular clock time intervals starting from 00:00
979 o'clock. The @var{time} value specified in @option{segment_time} is
980 used for setting the length of the splitting interval.
982 For example with @option{segment_time} set to "900" this makes it possible
983 to create files at 12:00 o'clock, 12:15, 12:30, etc.
985 Default value is "0".
987 @item segment_time_delta @var{delta}
988 Specify the accuracy time when selecting the start time for a
989 segment, expressed as a duration specification. Default value is "0".
991 When delta is specified a key-frame will start a new segment if its
992 PTS satisfies the relation:
994 PTS >= start_time - time_delta
997 This option is useful when splitting video content, which is always
998 split at GOP boundaries, in case a key frame is found just before the
999 specified split time.
1001 In particular may be used in combination with the @file{ffmpeg} option
1002 @var{force_key_frames}. The key frame times specified by
1003 @var{force_key_frames} may not be set accurately because of rounding
1004 issues, with the consequence that a key frame time may result set just
1005 before the specified time. For constant frame rate videos a value of
1006 1/(2*@var{frame_rate}) should address the worst case mismatch between
1007 the specified time and the time set by @var{force_key_frames}.
1009 @item segment_times @var{times}
1010 Specify a list of split points. @var{times} contains a list of comma
1011 separated duration specifications, in increasing order. See also
1012 the @option{segment_time} option.
1014 @item segment_frames @var{frames}
1015 Specify a list of split video frame numbers. @var{frames} contains a
1016 list of comma separated integer numbers, in increasing order.
1018 This option specifies to start a new segment whenever a reference
1019 stream key frame is found and the sequential number (starting from 0)
1020 of the frame is greater or equal to the next value in the list.
1022 @item segment_wrap @var{limit}
1023 Wrap around segment index once it reaches @var{limit}.
1025 @item segment_start_number @var{number}
1026 Set the sequence number of the first segment. Defaults to @code{0}.
1028 @item strftime @var{1|0}
1029 Use the @code{strftime} function to define the name of the new
1030 segments to write. If this is selected, the output segment name must
1031 contain a @code{strftime} function template. Default value is
1034 @item reset_timestamps @var{1|0}
1035 Reset timestamps at the begin of each segment, so that each segment
1036 will start with near-zero timestamps. It is meant to ease the playback
1037 of the generated segments. May not work with some combinations of
1038 muxers/codecs. It is set to @code{0} by default.
1040 @item initial_offset @var{offset}
1041 Specify timestamp offset to apply to the output packet timestamps. The
1042 argument must be a time duration specification, and defaults to 0.
1045 @subsection Examples
1049 Remux the content of file @file{in.mkv} to a list of segments
1050 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
1051 generated segments to @file{out.list}:
1053 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
1057 Segment input and set output format options for the output segments:
1059 ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
1063 Segment the input file according to the split points specified by the
1064 @var{segment_times} option:
1066 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
1070 Use the @command{ffmpeg} @option{force_key_frames}
1071 option to force key frames in the input at the specified location, together
1072 with the segment option @option{segment_time_delta} to account for
1073 possible roundings operated when setting key frame times.
1075 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
1076 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
1078 In order to force key frames on the input file, transcoding is
1082 Segment the input file by splitting the input file according to the
1083 frame numbers sequence specified with the @option{segment_frames} option:
1085 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
1089 Convert the @file{in.mkv} to TS segments using the @code{libx264}
1090 and @code{libfaac} encoders:
1092 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
1096 Segment the input file, and create an M3U8 live playlist (can be used
1097 as live HLS source):
1099 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
1100 -segment_list_flags +live -segment_time 10 out%03d.mkv
1104 @section smoothstreaming
1106 Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
1110 Specify the number of fragments kept in the manifest. Default 0 (keep all).
1112 @item extra_window_size
1113 Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
1115 @item lookahead_count
1116 Specify the number of lookahead fragments. Default 2.
1118 @item min_frag_duration
1119 Specify the minimum fragment duration (in microseconds). Default 5000000.
1121 @item remove_at_exit
1122 Specify whether to remove all fragments when finished. Default 0 (do not remove).
1128 The tee muxer can be used to write the same data to several files or any
1129 other kind of muxer. It can be used, for example, to both stream a video to
1130 the network and save it to disk at the same time.
1132 It is different from specifying several outputs to the @command{ffmpeg}
1133 command-line tool because the audio and video data will be encoded only once
1134 with the tee muxer; encoding can be a very expensive process. It is not
1135 useful when using the libavformat API directly because it is then possible
1136 to feed the same packets to several muxers directly.
1138 The slave outputs are specified in the file name given to the muxer,
1139 separated by '|'. If any of the slave name contains the '|' separator,
1140 leading or trailing spaces or any special character, it must be
1141 escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
1142 section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
1144 Muxer options can be specified for each slave by prepending them as a list of
1145 @var{key}=@var{value} pairs separated by ':', between square brackets. If
1146 the options values contain a special character or the ':' separator, they
1147 must be escaped; note that this is a second level escaping.
1149 The following special options are also recognized:
1152 Specify the format name. Useful if it cannot be guessed from the
1155 @item bsfs[/@var{spec}]
1156 Specify a list of bitstream filters to apply to the specified
1159 It is possible to specify to which streams a given bitstream filter
1160 applies, by appending a stream specifier to the option separated by
1161 @code{/}. @var{spec} must be a stream specifier (see @ref{Format
1162 stream specifiers}). If the stream specifier is not specified, the
1163 bitstream filters will be applied to all streams in the output.
1165 Several bitstream filters can be specified, separated by ",".
1168 Select the streams that should be mapped to the slave output,
1169 specified by a stream specifier. If not specified, this defaults to
1170 all the input streams.
1173 @subsection Examples
1177 Encode something and both archive it in a WebM file and stream it
1178 as MPEG-TS over UDP (the streams need to be explicitly mapped):
1180 ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
1181 "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
1185 Use @command{ffmpeg} to encode the input, and send the output
1186 to three different destinations. The @code{dump_extra} bitstream
1187 filter is used to add extradata information to all the output video
1188 keyframes packets, as requested by the MPEG-TS format. The select
1189 option is applied to @file{out.aac} in order to make it contain only
1192 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1193 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
1197 As below, but select only stream @code{a:1} for the audio output. Note
1198 that a second level escaping must be performed, as ":" is a special
1199 character used to separate options.
1201 ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
1202 -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
1206 Note: some codecs may need different options depending on the output format;
1207 the auto-detection of this can not work with the tee muxer. The main example
1208 is the @option{global_header} flag.
1210 @section webm_dash_manifest
1212 WebM DASH Manifest muxer.
1214 This muxer implements the WebM DASH Manifest specification to generate the DASH manifest XML.
1218 This muxer supports the following options:
1221 @item adaptation_sets
1222 This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
1223 unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
1224 audio and video streams. Any number of adaptation sets can be added using this option.
1229 ffmpeg -f webm_dash_manifest -i video1.webm \
1230 -f webm_dash_manifest -i video2.webm \
1231 -f webm_dash_manifest -i audio1.webm \
1232 -f webm_dash_manifest -i audio2.webm \
1233 -map 0 -map 1 -map 2 -map 3 \
1235 -f webm_dash_manifest \
1236 -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \