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 CRC (Cyclic Redundancy Check) testing format.
26 This muxer computes and prints the Adler-32 CRC of all the input audio
27 and video frames. By default audio frames are converted to signed
28 16-bit raw audio and video frames to raw video before computing the
31 The output of the muxer consists of a single line of the form:
32 CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
33 8 digits containing the CRC for all the decoded input frames.
35 For example to compute the CRC of the input, and store it in the file
38 ffmpeg -i INPUT -f crc out.crc
41 You can print the CRC to stdout with the command:
43 ffmpeg -i INPUT -f crc -
46 You can select the output format of each frame with @command{ffmpeg} by
47 specifying the audio and video codec and format. For example to
48 compute the CRC of the input audio converted to PCM unsigned 8-bit
49 and the input video converted to MPEG-2 video, use the command:
51 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
54 See also the @ref{framecrc} muxer.
59 Per-packet CRC (Cyclic Redundancy Check) testing format.
61 This muxer computes and prints the Adler-32 CRC for each audio
62 and video packet. By default audio frames are converted to signed
63 16-bit raw audio and video frames to raw video before computing the
66 The output of the muxer consists of a line for each audio and video
69 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
72 @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
75 For example to compute the CRC of the audio and video frames in
76 @file{INPUT}, converted to raw audio and video packets, and store it
77 in the file @file{out.crc}:
79 ffmpeg -i INPUT -f framecrc out.crc
82 To print the information to stdout, use the command:
84 ffmpeg -i INPUT -f framecrc -
87 With @command{ffmpeg}, you can select the output format to which the
88 audio and video frames are encoded before computing the CRC for each
89 packet by specifying the audio and video codec. For example, to
90 compute the CRC of each decoded input audio frame converted to PCM
91 unsigned 8-bit and of each decoded input video frame converted to
92 MPEG-2 video, use the command:
94 ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
97 See also the @ref{crc} muxer.
102 Per-packet MD5 testing format.
104 This muxer computes and prints the MD5 hash for each audio
105 and video packet. By default audio frames are converted to signed
106 16-bit raw audio and video frames to raw video before computing the
109 The output of the muxer consists of a line for each audio and video
112 @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5}
115 @var{MD5} is a hexadecimal number representing the computed MD5 hash
118 For example to compute the MD5 of the audio and video frames in
119 @file{INPUT}, converted to raw audio and video packets, and store it
120 in the file @file{out.md5}:
122 ffmpeg -i INPUT -f framemd5 out.md5
125 To print the information to stdout, use the command:
127 ffmpeg -i INPUT -f framemd5 -
130 See also the @ref{md5} muxer.
135 Apple HTTP Live Streaming muxer that segments MPEG-TS according to
136 the HTTP Live Streaming specification.
138 It creates a playlist file and numbered segment files. The output
139 filename specifies the playlist filename; the segment filenames
140 receive the same basename as the playlist, a sequential number and
144 ffmpeg -i in.nut out.m3u8
148 @item -hls_time @var{seconds}
149 Set the segment length in seconds.
150 @item -hls_list_size @var{size}
151 Set the maximum number of playlist entries.
152 @item -hls_wrap @var{wrap}
153 Set the number after which index wraps.
154 @item -start_number @var{number}
155 Start the sequence from @var{number}.
163 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
167 Size cannot exceed 256 pixels in any dimension
170 Only BMP and PNG images can be stored
173 If a BMP image is used, it must be one of the following pixel formats:
175 BMP Bit Depth FFmpeg Pixel Format
185 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
188 If a PNG image is used, it must use the rgba pixel format
196 The image file muxer writes video frames to image files.
198 The output filenames are specified by a pattern, which can be used to
199 produce sequentially numbered series of files.
200 The pattern may contain the string "%d" or "%0@var{N}d", this string
201 specifies the position of the characters representing a numbering in
202 the filenames. If the form "%0@var{N}d" is used, the string
203 representing the number in each filename is 0-padded to @var{N}
204 digits. The literal character '%' can be specified in the pattern with
207 If the pattern contains "%d" or "%0@var{N}d", the first filename of
208 the file list specified will contain the number 1, all the following
209 numbers will be sequential.
211 The pattern may contain a suffix which is used to automatically
212 determine the format of the image files to write.
214 For example the pattern "img-%03d.bmp" will specify a sequence of
215 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
216 @file{img-010.bmp}, etc.
217 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
218 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
221 The following example shows how to use @command{ffmpeg} for creating a
222 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
223 taking one image every second from the input video:
225 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
228 Note that with @command{ffmpeg}, if the format is not specified with the
229 @code{-f} option and the output filename specifies an image file
230 format, the image2 muxer is automatically selected, so the previous
231 command can be written as:
233 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
236 Note also that the pattern must not necessarily contain "%d" or
237 "%0@var{N}d", for example to create a single image file
238 @file{img.jpeg} from the input video you can employ the command:
240 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
244 @item start_number @var{number}
245 Start the sequence from @var{number}. Default value is 1. Must be a
248 @item updatefirst 1|0
249 If set to 1, update the first written image file again and
250 again. Default value is 0.
253 The image muxer supports the .Y.U.V image file format. This format is
254 special in that that each image frame consists of three files, for
255 each of the YUV420P components. To read or write this image file format,
256 specify the name of the '.Y' file. The muxer will automatically open the
257 '.U' and '.V' files as required.
264 This muxer computes and prints the MD5 hash of all the input audio
265 and video frames. By default audio frames are converted to signed
266 16-bit raw audio and video frames to raw video before computing the
269 The output of the muxer consists of a single line of the form:
270 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
271 the computed MD5 hash.
273 For example to compute the MD5 hash of the input converted to raw
274 audio and video, and store it in the file @file{out.md5}:
276 ffmpeg -i INPUT -f md5 out.md5
279 You can print the MD5 to stdout with the command:
281 ffmpeg -i INPUT -f md5 -
284 See also the @ref{framemd5} muxer.
286 @section MOV/MP4/ISMV
288 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
289 file has all the metadata about all packets stored in one location
290 (written at the end of the file, it can be moved to the start for
291 better playback by adding @var{faststart} to the @var{movflags}, or
292 using the @command{qt-faststart} tool). A fragmented
293 file consists of a number of fragments, where packets and metadata
294 about these packets are stored together. Writing a fragmented
295 file has the advantage that the file is decodable even if the
296 writing is interrupted (while a normal MOV/MP4 is undecodable if
297 it is not properly finished), and it requires less memory when writing
298 very long files (since writing normal MOV/MP4 files stores info about
299 every single packet in memory until the file is closed). The downside
300 is that it is less compatible with other applications.
302 Fragmentation is enabled by setting one of the AVOptions that define
303 how to cut the file into fragments:
306 @item -moov_size @var{bytes}
307 Reserves space for the moov atom at the beginning of the file instead of placing the
308 moov atom at the end. If the space reserved is insufficient, muxing will fail.
309 @item -movflags frag_keyframe
310 Start a new fragment at each video keyframe.
311 @item -frag_duration @var{duration}
312 Create fragments that are @var{duration} microseconds long.
313 @item -frag_size @var{size}
314 Create fragments that contain up to @var{size} bytes of payload data.
315 @item -movflags frag_custom
316 Allow the caller to manually choose when to cut fragments, by
317 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
318 the packets written so far. (This is only useful with other
319 applications integrating libavformat, not from @command{ffmpeg}.)
320 @item -min_frag_duration @var{duration}
321 Don't create fragments that are shorter than @var{duration} microseconds long.
324 If more than one condition is specified, fragments are cut when
325 one of the specified conditions is fulfilled. The exception to this is
326 @code{-min_frag_duration}, which has to be fulfilled for any of the other
329 Additionally, the way the output file is written can be adjusted
330 through a few other options:
333 @item -movflags empty_moov
334 Write an initial moov atom directly at the start of the file, without
335 describing any samples in it. Generally, an mdat/moov pair is written
336 at the start of the file, as a normal MOV/MP4 file, containing only
337 a short portion of the file. With this option set, there is no initial
338 mdat atom, and the moov atom only describes the tracks but has
341 Files written with this option set do not work in QuickTime.
342 This option is implicitly set when writing ismv (Smooth Streaming) files.
343 @item -movflags separate_moof
344 Write a separate moof (movie fragment) atom for each track. Normally,
345 packets for all tracks are written in a moof atom (which is slightly
346 more efficient), but with this option set, the muxer writes one moof/mdat
347 pair for each track, making it easier to separate tracks.
349 This option is implicitly set when writing ismv (Smooth Streaming) files.
350 @item -movflags faststart
351 Run a second pass moving the moov atom on top of the file. This
352 operation can take a while, and will not work in various situations such
353 as fragmented output, thus it is not enabled by default.
354 @item -movflags rtphint
355 Add RTP hinting tracks to the output file.
358 Smooth Streaming content can be pushed in real time to a publishing
359 point on IIS with this muxer. Example:
361 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
366 MPEG transport stream muxer.
368 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
370 The muxer options are:
373 @item -mpegts_original_network_id @var{number}
374 Set the original_network_id (default 0x0001). This is unique identifier
375 of a network in DVB. Its main use is in the unique identification of a
376 service through the path Original_Network_ID, Transport_Stream_ID.
377 @item -mpegts_transport_stream_id @var{number}
378 Set the transport_stream_id (default 0x0001). This identifies a
380 @item -mpegts_service_id @var{number}
381 Set the service_id (default 0x0001) also known as program in DVB.
382 @item -mpegts_pmt_start_pid @var{number}
383 Set the first PID for PMT (default 0x1000, max 0x1f00).
384 @item -mpegts_start_pid @var{number}
385 Set the first PID for data packets (default 0x0100, max 0x0f00).
388 The recognized metadata settings in mpegts muxer are @code{service_provider}
389 and @code{service_name}. If they are not set the default for
390 @code{service_provider} is "FFmpeg" and the default for
391 @code{service_name} is "Service01".
394 ffmpeg -i file.mpg -c copy \
395 -mpegts_original_network_id 0x1122 \
396 -mpegts_transport_stream_id 0x3344 \
397 -mpegts_service_id 0x5566 \
398 -mpegts_pmt_start_pid 0x1500 \
399 -mpegts_start_pid 0x150 \
400 -metadata service_provider="Some provider" \
401 -metadata service_name="Some Channel" \
409 This muxer does not generate any output file, it is mainly useful for
410 testing or benchmarking purposes.
412 For example to benchmark decoding with @command{ffmpeg} you can use the
415 ffmpeg -benchmark -i INPUT -f null out.null
418 Note that the above command does not read or write the @file{out.null}
419 file, but specifying the output file is required by the @command{ffmpeg}
422 Alternatively you can write the command as:
424 ffmpeg -benchmark -i INPUT -f null -
429 Matroska container muxer.
431 This muxer implements the matroska and webm container specs.
433 The recognized metadata settings in this muxer are:
437 @item title=@var{title name}
438 Name provided to a single track
443 @item language=@var{language name}
444 Specifies the language of the track in the Matroska languages form
449 @item stereo_mode=@var{mode}
450 Stereo 3D video layout of two views in a single video track
455 Both views are arranged side by side, Left-eye view is on the left
457 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
459 Both views are arranged in top-bottom orientation, Left-eye view is on top
460 @item checkerboard_rl
461 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
462 @item checkerboard_lr
463 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
464 @item row_interleaved_rl
465 Each view is constituted by a row based interleaving, Right-eye view is first row
466 @item row_interleaved_lr
467 Each view is constituted by a row based interleaving, Left-eye view is first row
468 @item col_interleaved_rl
469 Both views are arranged in a column based interleaving manner, Right-eye view is first column
470 @item col_interleaved_lr
471 Both views are arranged in a column based interleaving manner, Left-eye view is first column
472 @item anaglyph_cyan_red
473 All frames are in anaglyph format viewable through red-cyan filters
475 Both views are arranged side by side, Right-eye view is on the left
476 @item anaglyph_green_magenta
477 All frames are in anaglyph format viewable through green-magenta filters
479 Both eyes laced in one Block, Left-eye view is first
481 Both eyes laced in one Block, Right-eye view is first
485 For example a 3D WebM clip can be created using the following command line:
487 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
490 @section segment, stream_segment, ssegment
492 Basic stream segmenter.
494 The segmenter muxer outputs streams to a number of separate files of nearly
495 fixed duration. Output filename pattern can be set in a fashion similar to
498 @code{stream_segment} is a variant of the muxer used to write to
499 streaming output formats, i.e. which do not require global headers,
500 and is recommended for outputting e.g. to MPEG transport stream segments.
501 @code{ssegment} is a shorter alias for @code{stream_segment}.
503 Every segment starts with a keyframe of the selected reference stream,
504 which is set through the @option{reference_stream} option.
506 Note that if you want accurate splitting for a video file, you need to
507 make the input key frames correspond to the exact splitting times
508 expected by the segmenter, or the segment muxer will start the new
509 segment with the key frame found next after the specified start
512 The segment muxer works best with a single constant frame rate video.
514 Optionally it can generate a list of the created segments, by setting
515 the option @var{segment_list}. The list type is specified by the
516 @var{segment_list_type} option.
518 The segment muxer supports the following options:
521 @item reference_stream @var{specifier}
522 Set the reference stream, as specified by the string @var{specifier}.
523 If @var{specifier} is set to @code{auto}, the reference is choosen
524 automatically. Otherwise it must be a stream specifier (see the ``Stream
525 specifiers'' chapter in the ffmpeg manual) which specifies the
526 reference stream. The default value is ``auto''.
528 @item segment_format @var{format}
529 Override the inner container format, by default it is guessed by the filename
532 @item segment_list @var{name}
533 Generate also a listfile named @var{name}. If not specified no
534 listfile is generated.
536 @item segment_list_flags @var{flags}
537 Set flags affecting the segment list generation.
539 It currently supports the following flags:
542 Allow caching (only affects M3U8 list files).
545 Allow live-friendly file generation.
548 Default value is @code{cache}.
550 @item segment_list_size @var{size}
551 Update the list file so that it contains at most the last @var{size}
552 segments. If 0 the list file will contain all the segments. Default
555 @item segment_list type @var{type}
556 Specify the format for the segment list file.
558 The following values are recognized:
561 Generate a flat list for the created segments, one segment per line.
564 Generate a list for the created segments, one segment per line,
565 each line matching the format (comma-separated values):
567 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
570 @var{segment_filename} is the name of the output file generated by the
571 muxer according to the provided pattern. CSV escaping (according to
572 RFC4180) is applied if required.
574 @var{segment_start_time} and @var{segment_end_time} specify
575 the segment start and end time expressed in seconds.
577 A list file with the suffix @code{".csv"} or @code{".ext"} will
578 auto-select this format.
580 @code{ext} is deprecated in favor or @code{csv}.
583 Generate an extended M3U8 file, version 3, compliant with
584 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
586 A list file with the suffix @code{".m3u8"} will auto-select this format.
589 If not specified the type is guessed from the list file name suffix.
591 @item segment_time @var{time}
592 Set segment duration to @var{time}, the value must be a duration
593 specification. Default value is "2". See also the
594 @option{segment_times} option.
596 Note that splitting may not be accurate, unless you force the
597 reference stream key-frames at the given time. See the introductory
598 notice and the examples below.
600 @item segment_time_delta @var{delta}
601 Specify the accuracy time when selecting the start time for a
602 segment, expressed as a duration specification. Default value is "0".
604 When delta is specified a key-frame will start a new segment if its
605 PTS satisfies the relation:
607 PTS >= start_time - time_delta
610 This option is useful when splitting video content, which is always
611 split at GOP boundaries, in case a key frame is found just before the
612 specified split time.
614 In particular may be used in combination with the @file{ffmpeg} option
615 @var{force_key_frames}. The key frame times specified by
616 @var{force_key_frames} may not be set accurately because of rounding
617 issues, with the consequence that a key frame time may result set just
618 before the specified time. For constant frame rate videos a value of
619 1/2*@var{frame_rate} should address the worst case mismatch between
620 the specified time and the time set by @var{force_key_frames}.
622 @item segment_times @var{times}
623 Specify a list of split points. @var{times} contains a list of comma
624 separated duration specifications, in increasing order. See also
625 the @option{segment_time} option.
627 @item segment_frames @var{frames}
628 Specify a list of split video frame numbers. @var{frames} contains a
629 list of comma separated integer numbers, in increasing order.
631 This option specifies to start a new segment whenever a reference
632 stream key frame is found and the sequential number (starting from 0)
633 of the frame is greater or equal to the next value in the list.
635 @item segment_wrap @var{limit}
636 Wrap around segment index once it reaches @var{limit}.
638 @item segment_start_number @var{number}
639 Set the sequence number of the first segment. Defaults to @code{0}.
641 @item reset_timestamps @var{1|0}
642 Reset timestamps at the begin of each segment, so that each segment
643 will start with near-zero timestamps. It is meant to ease the playback
644 of the generated segments. May not work with some combinations of
645 muxers/codecs. It is set to @code{0} by default.
652 To remux the content of file @file{in.mkv} to a list of segments
653 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
654 generated segments to @file{out.list}:
656 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
660 As the example above, but segment the input file according to the split
661 points specified by the @var{segment_times} option:
663 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
667 As the example above, but use the @code{ffmpeg} @var{force_key_frames}
668 option to force key frames in the input at the specified location, together
669 with the segment option @var{segment_time_delta} to account for
670 possible roundings operated when setting key frame times.
672 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
673 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
675 In order to force key frames on the input file, transcoding is
679 Segment the input file by splitting the input file according to the
680 frame numbers sequence specified with the @var{segment_frames} option:
682 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
686 To convert the @file{in.mkv} to TS segments using the @code{libx264}
687 and @code{libfaac} encoders:
689 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
693 Segment the input file, and create an M3U8 live playlist (can be used
696 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
697 -segment_list_flags +live -segment_time 10 out%03d.mkv
703 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
704 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
705 @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
706 not written by default, but may be enabled with the @code{write_id3v1} option.
708 For seekable output the muxer also writes a Xing frame at the beginning, which
709 contains the number of frames in the file. It is useful for computing duration
712 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
713 are supplied to the muxer in form of a video stream with a single packet. There
714 can be any number of those streams, each will correspond to a single APIC frame.
715 The stream metadata tags @var{title} and @var{comment} map to APIC
716 @var{description} and @var{picture type} respectively. See
717 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
719 Note that the APIC frames must be written at the beginning, so the muxer will
720 buffer the audio frames until it gets all the pictures. It is therefore advised
721 to provide the pictures as soon as possible to avoid excessive buffering.
725 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
727 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
730 Attach a picture to an mp3:
732 ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
733 -metadata:s:v comment="Cover (Front)" out.mp3
741 @item -page_duration @var{duration}
742 Preferred page duration, in microseconds. The muxer will attempt to create
743 pages that are approximately @var{duration} microseconds long. This allows the
744 user to compromise between seek granularity and container overhead. The default
745 is 1 second. A value of 0 will fill all segments, making pages as large as
746 possible. A value of 1 will effectively use 1 packet-per-page in most
747 situations, giving a small seek granularity at the cost of additional container