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}.
248 The image muxer supports the .Y.U.V image file format. This format is
249 special in that that each image frame consists of three files, for
250 each of the YUV420P components. To read or write this image file format,
251 specify the name of the '.Y' file. The muxer will automatically open the
252 '.U' and '.V' files as required.
259 This muxer computes and prints the MD5 hash of all the input audio
260 and video frames. By default audio frames are converted to signed
261 16-bit raw audio and video frames to raw video before computing the
264 The output of the muxer consists of a single line of the form:
265 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
266 the computed MD5 hash.
268 For example to compute the MD5 hash of the input converted to raw
269 audio and video, and store it in the file @file{out.md5}:
271 ffmpeg -i INPUT -f md5 out.md5
274 You can print the MD5 to stdout with the command:
276 ffmpeg -i INPUT -f md5 -
279 See also the @ref{framemd5} muxer.
281 @section MOV/MP4/ISMV
283 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
284 file has all the metadata about all packets stored in one location
285 (written at the end of the file, it can be moved to the start for
286 better playback by adding @var{faststart} to the @var{movflags}, or
287 using the @command{qt-faststart} tool). A fragmented
288 file consists of a number of fragments, where packets and metadata
289 about these packets are stored together. Writing a fragmented
290 file has the advantage that the file is decodable even if the
291 writing is interrupted (while a normal MOV/MP4 is undecodable if
292 it is not properly finished), and it requires less memory when writing
293 very long files (since writing normal MOV/MP4 files stores info about
294 every single packet in memory until the file is closed). The downside
295 is that it is less compatible with other applications.
297 Fragmentation is enabled by setting one of the AVOptions that define
298 how to cut the file into fragments:
301 @item -moov_size @var{bytes}
302 Reserves space for the moov atom at the beginning of the file instead of placing the
303 moov atom at the end. If the space reserved is insufficient, muxing will fail.
304 @item -movflags frag_keyframe
305 Start a new fragment at each video keyframe.
306 @item -frag_duration @var{duration}
307 Create fragments that are @var{duration} microseconds long.
308 @item -frag_size @var{size}
309 Create fragments that contain up to @var{size} bytes of payload data.
310 @item -movflags frag_custom
311 Allow the caller to manually choose when to cut fragments, by
312 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
313 the packets written so far. (This is only useful with other
314 applications integrating libavformat, not from @command{ffmpeg}.)
315 @item -min_frag_duration @var{duration}
316 Don't create fragments that are shorter than @var{duration} microseconds long.
319 If more than one condition is specified, fragments are cut when
320 one of the specified conditions is fulfilled. The exception to this is
321 @code{-min_frag_duration}, which has to be fulfilled for any of the other
324 Additionally, the way the output file is written can be adjusted
325 through a few other options:
328 @item -movflags empty_moov
329 Write an initial moov atom directly at the start of the file, without
330 describing any samples in it. Generally, an mdat/moov pair is written
331 at the start of the file, as a normal MOV/MP4 file, containing only
332 a short portion of the file. With this option set, there is no initial
333 mdat atom, and the moov atom only describes the tracks but has
336 Files written with this option set do not work in QuickTime.
337 This option is implicitly set when writing ismv (Smooth Streaming) files.
338 @item -movflags separate_moof
339 Write a separate moof (movie fragment) atom for each track. Normally,
340 packets for all tracks are written in a moof atom (which is slightly
341 more efficient), but with this option set, the muxer writes one moof/mdat
342 pair for each track, making it easier to separate tracks.
344 This option is implicitly set when writing ismv (Smooth Streaming) files.
345 @item -movflags faststart
346 Run a second pass moving the moov atom on top of the file. This
347 operation can take a while, and will not work in various situations such
348 as fragmented output, thus it is not enabled by default.
351 Smooth Streaming content can be pushed in real time to a publishing
352 point on IIS with this muxer. Example:
354 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
359 MPEG transport stream muxer.
361 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
363 The muxer options are:
366 @item -mpegts_original_network_id @var{number}
367 Set the original_network_id (default 0x0001). This is unique identifier
368 of a network in DVB. Its main use is in the unique identification of a
369 service through the path Original_Network_ID, Transport_Stream_ID.
370 @item -mpegts_transport_stream_id @var{number}
371 Set the transport_stream_id (default 0x0001). This identifies a
373 @item -mpegts_service_id @var{number}
374 Set the service_id (default 0x0001) also known as program in DVB.
375 @item -mpegts_pmt_start_pid @var{number}
376 Set the first PID for PMT (default 0x1000, max 0x1f00).
377 @item -mpegts_start_pid @var{number}
378 Set the first PID for data packets (default 0x0100, max 0x0f00).
381 The recognized metadata settings in mpegts muxer are @code{service_provider}
382 and @code{service_name}. If they are not set the default for
383 @code{service_provider} is "FFmpeg" and the default for
384 @code{service_name} is "Service01".
387 ffmpeg -i file.mpg -c copy \
388 -mpegts_original_network_id 0x1122 \
389 -mpegts_transport_stream_id 0x3344 \
390 -mpegts_service_id 0x5566 \
391 -mpegts_pmt_start_pid 0x1500 \
392 -mpegts_start_pid 0x150 \
393 -metadata service_provider="Some provider" \
394 -metadata service_name="Some Channel" \
402 This muxer does not generate any output file, it is mainly useful for
403 testing or benchmarking purposes.
405 For example to benchmark decoding with @command{ffmpeg} you can use the
408 ffmpeg -benchmark -i INPUT -f null out.null
411 Note that the above command does not read or write the @file{out.null}
412 file, but specifying the output file is required by the @command{ffmpeg}
415 Alternatively you can write the command as:
417 ffmpeg -benchmark -i INPUT -f null -
422 Matroska container muxer.
424 This muxer implements the matroska and webm container specs.
426 The recognized metadata settings in this muxer are:
430 @item title=@var{title name}
431 Name provided to a single track
436 @item language=@var{language name}
437 Specifies the language of the track in the Matroska languages form
442 @item stereo_mode=@var{mode}
443 Stereo 3D video layout of two views in a single video track
448 Both views are arranged side by side, Left-eye view is on the left
450 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
452 Both views are arranged in top-bottom orientation, Left-eye view is on top
453 @item checkerboard_rl
454 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
455 @item checkerboard_lr
456 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
457 @item row_interleaved_rl
458 Each view is constituted by a row based interleaving, Right-eye view is first row
459 @item row_interleaved_lr
460 Each view is constituted by a row based interleaving, Left-eye view is first row
461 @item col_interleaved_rl
462 Both views are arranged in a column based interleaving manner, Right-eye view is first column
463 @item col_interleaved_lr
464 Both views are arranged in a column based interleaving manner, Left-eye view is first column
465 @item anaglyph_cyan_red
466 All frames are in anaglyph format viewable through red-cyan filters
468 Both views are arranged side by side, Right-eye view is on the left
469 @item anaglyph_green_magenta
470 All frames are in anaglyph format viewable through green-magenta filters
472 Both eyes laced in one Block, Left-eye view is first
474 Both eyes laced in one Block, Right-eye view is first
478 For example a 3D WebM clip can be created using the following command line:
480 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
483 @section segment, stream_segment, ssegment
485 Basic stream segmenter.
487 The segmenter muxer outputs streams to a number of separate files of nearly
488 fixed duration. Output filename pattern can be set in a fashion similar to
491 @code{stream_segment} is a variant of the muxer used to write to
492 streaming output formats, i.e. which do not require global headers,
493 and is recommended for outputting e.g. to MPEG transport stream segments.
494 @code{ssegment} is a shorter alias for @code{stream_segment}.
496 Every segment starts with a video keyframe, if a video stream is present.
497 Note that if you want accurate splitting for a video file, you need to
498 make the input key frames correspond to the exact splitting times
499 expected by the segmenter, or the segment muxer will start the new
500 segment with the key frame found next after the specified start
503 The segment muxer works best with a single constant frame rate video.
505 Optionally it can generate a list of the created segments, by setting
506 the option @var{segment_list}. The list type is specified by the
507 @var{segment_list_type} option.
509 The segment muxer supports the following options:
512 @item segment_format @var{format}
513 Override the inner container format, by default it is guessed by the filename
515 @item segment_list @var{name}
516 Generate also a listfile named @var{name}. If not specified no
517 listfile is generated.
518 @item segment_list_flags @var{flags}
519 Set flags affecting the segment list generation.
521 It currently supports the following flags:
524 Allow caching (only affects M3U8 list files).
527 Allow live-friendly file generation.
529 This currently only affects M3U8 lists. In particular, write a fake
530 EXT-X-TARGETDURATION duration field at the top of the file, based on
531 the specified @var{segment_time}.
534 Default value is @code{cache}.
536 @item segment_list_size @var{size}
537 Overwrite the listfile once it reaches @var{size} entries. If 0
538 the listfile is never overwritten. Default value is 0.
539 @item segment_list type @var{type}
540 Specify the format for the segment list file.
542 The following values are recognized:
545 Generate a flat list for the created segments, one segment per line.
548 Generate a list for the created segments, one segment per line,
549 each line matching the format (comma-separated values):
551 @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
554 @var{segment_filename} is the name of the output file generated by the
555 muxer according to the provided pattern. CSV escaping (according to
556 RFC4180) is applied if required.
558 @var{segment_start_time} and @var{segment_end_time} specify
559 the segment start and end time expressed in seconds.
561 A list file with the suffix @code{".csv"} or @code{".ext"} will
562 auto-select this format.
564 @code{ext} is deprecated in favor or @code{csv}.
567 Generate an extended M3U8 file, version 4, compliant with
568 @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming-08.txt}.
570 A list file with the suffix @code{".m3u8"} will auto-select this format.
573 If not specified the type is guessed from the list file name suffix.
574 @item segment_time @var{time}
575 Set segment duration to @var{time}. Default value is "2".
576 @item segment_time_delta @var{delta}
577 Specify the accuracy time when selecting the start time for a
578 segment. Default value is "0".
580 When delta is specified a key-frame will start a new segment if its
581 PTS satisfies the relation:
583 PTS >= start_time - time_delta
586 This option is useful when splitting video content, which is always
587 split at GOP boundaries, in case a key frame is found just before the
588 specified split time.
590 In particular may be used in combination with the @file{ffmpeg} option
591 @var{force_key_frames}. The key frame times specified by
592 @var{force_key_frames} may not be set accurately because of rounding
593 issues, with the consequence that a key frame time may result set just
594 before the specified time. For constant frame rate videos a value of
595 1/2*@var{frame_rate} should address the worst case mismatch between
596 the specified time and the time set by @var{force_key_frames}.
598 @item segment_times @var{times}
599 Specify a list of split points. @var{times} contains a list of comma
600 separated duration specifications, in increasing order.
602 @item segment_wrap @var{limit}
603 Wrap around segment index once it reaches @var{limit}.
605 @item segment_start_number @var{number}
606 Set the sequence number of the first segment. Defaults to @code{0}.
608 @item reset_timestamps @var{1|0}
609 Reset timestamps at the begin of each segment, so that each segment
610 will start with near-zero timestamps. It is meant to ease the playback
611 of the generated segments. May not work with some combinations of
612 muxers/codecs. It is set to @code{0} by default.
615 Some examples follow.
619 To remux the content of file @file{in.mkv} to a list of segments
620 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
621 generated segments to @file{out.list}:
623 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
627 As the example above, but segment the input file according to the split
628 points specified by the @var{segment_times} option:
630 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
634 As the example above, but use the @code{ffmpeg} @var{force_key_frames}
635 option to force key frames in the input at the specified location, together
636 with the segment option @var{segment_time_delta} to account for
637 possible roundings operated when setting key frame times.
639 ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -vcodec mpeg4 -acodec pcm_s16le -map 0 \
640 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
642 In order to force key frames on the input file, transcoding is
646 To convert the @file{in.mkv} to TS segments using the @code{libx264}
647 and @code{libfaac} encoders:
649 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
653 Segment the input file, and create an M3U8 live playlist (can be used
656 ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
657 -segment_list_flags +live -segment_time 10 out%03d.mkv
663 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
664 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
665 @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
666 not written by default, but may be enabled with the @code{write_id3v1} option.
668 For seekable output the muxer also writes a Xing frame at the beginning, which
669 contains the number of frames in the file. It is useful for computing duration
672 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
673 are supplied to the muxer in form of a video stream with a single packet. There
674 can be any number of those streams, each will correspond to a single APIC frame.
675 The stream metadata tags @var{title} and @var{comment} map to APIC
676 @var{description} and @var{picture type} respectively. See
677 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
679 Note that the APIC frames must be written at the beginning, so the muxer will
680 buffer the audio frames until it gets all the pictures. It is therefore advised
681 to provide the pictures as soon as possible to avoid excessive buffering.
685 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
687 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
690 Attach a picture to an mp3:
692 ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
693 -metadata:s:v comment="Cover (Front)" out.mp3