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 segment length in seconds
149 @item -hls_list_size maximum number of playlist entries
150 @item -hls_wrap number after which index wraps
158 Microsoft's icon file format (ICO) has some strict limitations that should be noted:
162 Size cannot exceed 256 pixels in any dimension
165 Only BMP and PNG images can be stored
168 If a BMP image is used, it must be one of the following pixel formats:
170 BMP Bit Depth FFmpeg Pixel Format
180 If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
183 If a PNG image is used, it must use the rgba pixel format
191 The image file muxer writes video frames to image files.
193 The output filenames are specified by a pattern, which can be used to
194 produce sequentially numbered series of files.
195 The pattern may contain the string "%d" or "%0@var{N}d", this string
196 specifies the position of the characters representing a numbering in
197 the filenames. If the form "%0@var{N}d" is used, the string
198 representing the number in each filename is 0-padded to @var{N}
199 digits. The literal character '%' can be specified in the pattern with
202 If the pattern contains "%d" or "%0@var{N}d", the first filename of
203 the file list specified will contain the number 1, all the following
204 numbers will be sequential.
206 The pattern may contain a suffix which is used to automatically
207 determine the format of the image files to write.
209 For example the pattern "img-%03d.bmp" will specify a sequence of
210 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
211 @file{img-010.bmp}, etc.
212 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
213 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
216 The following example shows how to use @command{ffmpeg} for creating a
217 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
218 taking one image every second from the input video:
220 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
223 Note that with @command{ffmpeg}, if the format is not specified with the
224 @code{-f} option and the output filename specifies an image file
225 format, the image2 muxer is automatically selected, so the previous
226 command can be written as:
228 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
231 Note also that the pattern must not necessarily contain "%d" or
232 "%0@var{N}d", for example to create a single image file
233 @file{img.jpeg} from the input video you can employ the command:
235 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
238 The image muxer supports the .Y.U.V image file format. This format is
239 special in that that each image frame consists of three files, for
240 each of the YUV420P components. To read or write this image file format,
241 specify the name of the '.Y' file. The muxer will automatically open the
242 '.U' and '.V' files as required.
249 This muxer computes and prints the MD5 hash of all the input audio
250 and video frames. By default audio frames are converted to signed
251 16-bit raw audio and video frames to raw video before computing the
254 The output of the muxer consists of a single line of the form:
255 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
256 the computed MD5 hash.
258 For example to compute the MD5 hash of the input converted to raw
259 audio and video, and store it in the file @file{out.md5}:
261 ffmpeg -i INPUT -f md5 out.md5
264 You can print the MD5 to stdout with the command:
266 ffmpeg -i INPUT -f md5 -
269 See also the @ref{framemd5} muxer.
271 @section MOV/MP4/ISMV
273 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
274 file has all the metadata about all packets stored in one location
275 (written at the end of the file, it can be moved to the start for
276 better playback by adding @var{faststart} to the @var{movflags}, or
277 using the @command{qt-faststart} tool). A fragmented
278 file consists of a number of fragments, where packets and metadata
279 about these packets are stored together. Writing a fragmented
280 file has the advantage that the file is decodable even if the
281 writing is interrupted (while a normal MOV/MP4 is undecodable if
282 it is not properly finished), and it requires less memory when writing
283 very long files (since writing normal MOV/MP4 files stores info about
284 every single packet in memory until the file is closed). The downside
285 is that it is less compatible with other applications.
287 Fragmentation is enabled by setting one of the AVOptions that define
288 how to cut the file into fragments:
291 @item -moov_size @var{bytes}
292 Reserves space for the moov atom at the beginning of the file instead of placing the
293 moov atom at the end. If the space reserved is insufficient, muxing will fail.
294 @item -movflags frag_keyframe
295 Start a new fragment at each video keyframe.
296 @item -frag_duration @var{duration}
297 Create fragments that are @var{duration} microseconds long.
298 @item -frag_size @var{size}
299 Create fragments that contain up to @var{size} bytes of payload data.
300 @item -movflags frag_custom
301 Allow the caller to manually choose when to cut fragments, by
302 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
303 the packets written so far. (This is only useful with other
304 applications integrating libavformat, not from @command{ffmpeg}.)
305 @item -min_frag_duration @var{duration}
306 Don't create fragments that are shorter than @var{duration} microseconds long.
309 If more than one condition is specified, fragments are cut when
310 one of the specified conditions is fulfilled. The exception to this is
311 @code{-min_frag_duration}, which has to be fulfilled for any of the other
314 Additionally, the way the output file is written can be adjusted
315 through a few other options:
318 @item -movflags empty_moov
319 Write an initial moov atom directly at the start of the file, without
320 describing any samples in it. Generally, an mdat/moov pair is written
321 at the start of the file, as a normal MOV/MP4 file, containing only
322 a short portion of the file. With this option set, there is no initial
323 mdat atom, and the moov atom only describes the tracks but has
326 Files written with this option set do not work in QuickTime.
327 This option is implicitly set when writing ismv (Smooth Streaming) files.
328 @item -movflags separate_moof
329 Write a separate moof (movie fragment) atom for each track. Normally,
330 packets for all tracks are written in a moof atom (which is slightly
331 more efficient), but with this option set, the muxer writes one moof/mdat
332 pair for each track, making it easier to separate tracks.
334 This option is implicitly set when writing ismv (Smooth Streaming) files.
335 @item -movflags faststart
336 Run a second pass moving the moov atom on top of the file. This
337 operation can take a while, and will not work in various situations such
338 as fragmented output, thus it is not enabled by default.
341 Smooth Streaming content can be pushed in real time to a publishing
342 point on IIS with this muxer. Example:
344 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
349 MPEG transport stream muxer.
351 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
353 The muxer options are:
356 @item -mpegts_original_network_id @var{number}
357 Set the original_network_id (default 0x0001). This is unique identifier
358 of a network in DVB. Its main use is in the unique identification of a
359 service through the path Original_Network_ID, Transport_Stream_ID.
360 @item -mpegts_transport_stream_id @var{number}
361 Set the transport_stream_id (default 0x0001). This identifies a
363 @item -mpegts_service_id @var{number}
364 Set the service_id (default 0x0001) also known as program in DVB.
365 @item -mpegts_pmt_start_pid @var{number}
366 Set the first PID for PMT (default 0x1000, max 0x1f00).
367 @item -mpegts_start_pid @var{number}
368 Set the first PID for data packets (default 0x0100, max 0x0f00).
371 The recognized metadata settings in mpegts muxer are @code{service_provider}
372 and @code{service_name}. If they are not set the default for
373 @code{service_provider} is "FFmpeg" and the default for
374 @code{service_name} is "Service01".
377 ffmpeg -i file.mpg -c copy \
378 -mpegts_original_network_id 0x1122 \
379 -mpegts_transport_stream_id 0x3344 \
380 -mpegts_service_id 0x5566 \
381 -mpegts_pmt_start_pid 0x1500 \
382 -mpegts_start_pid 0x150 \
383 -metadata service_provider="Some provider" \
384 -metadata service_name="Some Channel" \
392 This muxer does not generate any output file, it is mainly useful for
393 testing or benchmarking purposes.
395 For example to benchmark decoding with @command{ffmpeg} you can use the
398 ffmpeg -benchmark -i INPUT -f null out.null
401 Note that the above command does not read or write the @file{out.null}
402 file, but specifying the output file is required by the @command{ffmpeg}
405 Alternatively you can write the command as:
407 ffmpeg -benchmark -i INPUT -f null -
412 Matroska container muxer.
414 This muxer implements the matroska and webm container specs.
416 The recognized metadata settings in this muxer are:
420 @item title=@var{title name}
421 Name provided to a single track
426 @item language=@var{language name}
427 Specifies the language of the track in the Matroska languages form
432 @item stereo_mode=@var{mode}
433 Stereo 3D video layout of two views in a single video track
438 Both views are arranged side by side, Left-eye view is on the left
440 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
442 Both views are arranged in top-bottom orientation, Left-eye view is on top
443 @item checkerboard_rl
444 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
445 @item checkerboard_lr
446 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
447 @item row_interleaved_rl
448 Each view is constituted by a row based interleaving, Right-eye view is first row
449 @item row_interleaved_lr
450 Each view is constituted by a row based interleaving, Left-eye view is first row
451 @item col_interleaved_rl
452 Both views are arranged in a column based interleaving manner, Right-eye view is first column
453 @item col_interleaved_lr
454 Both views are arranged in a column based interleaving manner, Left-eye view is first column
455 @item anaglyph_cyan_red
456 All frames are in anaglyph format viewable through red-cyan filters
458 Both views are arranged side by side, Right-eye view is on the left
459 @item anaglyph_green_magenta
460 All frames are in anaglyph format viewable through green-magenta filters
462 Both eyes laced in one Block, Left-eye view is first
464 Both eyes laced in one Block, Right-eye view is first
468 For example a 3D WebM clip can be created using the following command line:
470 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
473 @section segment, stream_segment, ssegment
475 Basic stream segmenter.
477 The segmenter muxer outputs streams to a number of separate files of nearly
478 fixed duration. Output filename pattern can be set in a fashion similar to
481 @code{stream_segment} is a variant of the muxer used to write to
482 streaming output formats, i.e. which do not require global headers,
483 and is recommended for outputting e.g. to MPEG transport stream segments.
484 @code{ssegment} is a shorter alias for @code{stream_segment}.
486 Every segment starts with a video keyframe, if a video stream is present.
487 Note that if you want accurate splitting for a video file, you need to
488 make the input key frames correspond to the exact splitting times
489 expected by the segmenter, or the segment muxer will start the new
490 segment with the key frame found next after the specified start
493 The segment muxer works best with a single constant frame rate video.
495 Optionally it can generate a list of the created segments, by setting
496 the option @var{segment_list}. The list type is specified by the
497 @var{segment_list_type} option.
499 The segment muxer supports the following options:
502 @item segment_format @var{format}
503 Override the inner container format, by default it is guessed by the filename
505 @item segment_list @var{name}
506 Generate also a listfile named @var{name}. If not specified no
507 listfile is generated.
508 @item segment_list_flags @var{flags}
509 Set flags affecting the segment list generation.
511 It currently supports the following flags:
514 Allow caching (only affects M3U8 list files).
517 Allow live-friendly file generation.
519 This currently only affects M3U8 lists. In particular, write a fake
520 EXT-X-TARGETDURATION duration field at the top of the file, based on
521 the specified @var{segment_time}.
524 Default value is @code{cache}.
526 @item segment_list_size @var{size}
527 Overwrite the listfile once it reaches @var{size} entries. If 0
528 the listfile is never overwritten. Default value is 0.
529 @item segment_list type @var{type}
530 Specify the format for the segment list file.
532 The following values are recognized:
535 Generate a flat list for the created segments, one segment per line.
538 Generate a list for the created segments, one segment per line,
539 each line matching the format (comma-separated values):
541 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
544 @var{segment_filename} is the name of the output file generated by the
545 muxer according to the provided pattern. CSV escaping (according to
546 RFC4180) is applied if required.
548 @var{segment_start_time} and @var{segment_end_time} specify
549 the segment start and end time expressed in seconds.
551 A list file with the suffix @code{".csv"} or @code{".ext"} will
552 auto-select this format.
554 @code{ext} is deprecated in favor or @code{csv}.
557 Generate an extended M3U8 file, version 4, compliant with
558 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming-08.txt}.
560 A list file with the suffix @code{".m3u8"} will auto-select this format.
563 If not specified the type is guessed from the list file name suffix.
564 @item segment_time @var{time}
565 Set segment duration to @var{time}. Default value is "2".
566 @item segment_time_delta @var{delta}
567 Specify the accuracy time when selecting the start time for a
568 segment. Default value is "0".
570 When delta is specified a key-frame will start a new segment if its
571 PTS satisfies the relation:
573 PTS >= start_time - time_delta
576 This option is useful when splitting video content, which is always
577 split at GOP boundaries, in case a key frame is found just before the
578 specified split time.
580 In particular may be used in combination with the @file{ffmpeg} option
581 @var{force_key_frames}. The key frame times specified by
582 @var{force_key_frames} may not be set accurately because of rounding
583 issues, with the consequence that a key frame time may result set just
584 before the specified time. For constant frame rate videos a value of
585 1/2*@var{frame_rate} should address the worst case mismatch between
586 the specified time and the time set by @var{force_key_frames}.
588 @item segment_times @var{times}
589 Specify a list of split points. @var{times} contains a list of comma
590 separated duration specifications, in increasing order.
591 @item segment_wrap @var{limit}
592 Wrap around segment index once it reaches @var{limit}.
595 Some examples follow.
599 To remux the content of file @file{in.mkv} to a list of segments
600 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
601 generated segments to @file{out.list}:
603 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
607 As the example above, but segment the input file according to the split
608 points specified by the @var{segment_times} option:
610 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
614 As the example above, but use the @code{ffmpeg} @var{force_key_frames}
615 option to force key frames in the input at the specified location, together
616 with the segment option @var{segment_time_delta} to account for
617 possible roundings operated when setting key frame times.
619 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -vcodec mpeg4 -acodec pcm_s16le -map 0 \
620 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
622 In order to force key frames on the input file, transcoding is
626 To convert the @file{in.mkv} to TS segments using the @code{libx264}
627 and @code{libfaac} encoders:
629 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
633 Segment the input file, and create an M3U8 live playlist (can be used
636 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
637 -segment_list_flags +live -segment_time 10 out%03d.mkv
643 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
644 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
645 @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
646 not written by default, but may be enabled with the @code{write_id3v1} option.
648 For seekable output the muxer also writes a Xing frame at the beginning, which
649 contains the number of frames in the file. It is useful for computing duration
652 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
653 are supplied to the muxer in form of a video stream with a single packet. There
654 can be any number of those streams, each will correspond to a single APIC frame.
655 The stream metadata tags @var{title} and @var{comment} map to APIC
656 @var{description} and @var{picture type} respectively. See
657 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
659 Note that the APIC frames must be written at the beginning, so the muxer will
660 buffer the audio frames until it gets all the pictures. It is therefore advised
661 to provide the pictures as soon as possible to avoid excessive buffering.
665 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
667 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
670 Attach a picture to an mp3:
672 ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
673 -metadata:s:v comment="Cover (Front)" out.mp3