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.
137 The image file muxer writes video frames to image files.
139 The output filenames are specified by a pattern, which can be used to
140 produce sequentially numbered series of files.
141 The pattern may contain the string "%d" or "%0@var{N}d", this string
142 specifies the position of the characters representing a numbering in
143 the filenames. If the form "%0@var{N}d" is used, the string
144 representing the number in each filename is 0-padded to @var{N}
145 digits. The literal character '%' can be specified in the pattern with
148 If the pattern contains "%d" or "%0@var{N}d", the first filename of
149 the file list specified will contain the number 1, all the following
150 numbers will be sequential.
152 The pattern may contain a suffix which is used to automatically
153 determine the format of the image files to write.
155 For example the pattern "img-%03d.bmp" will specify a sequence of
156 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
157 @file{img-010.bmp}, etc.
158 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
159 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
162 The following example shows how to use @command{ffmpeg} for creating a
163 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
164 taking one image every second from the input video:
166 ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
169 Note that with @command{ffmpeg}, if the format is not specified with the
170 @code{-f} option and the output filename specifies an image file
171 format, the image2 muxer is automatically selected, so the previous
172 command can be written as:
174 ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
177 Note also that the pattern must not necessarily contain "%d" or
178 "%0@var{N}d", for example to create a single image file
179 @file{img.jpeg} from the input video you can employ the command:
181 ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
184 The image muxer supports the .Y.U.V image file format. This format is
185 special in that that each image frame consists of three files, for
186 each of the YUV420P components. To read or write this image file format,
187 specify the name of the '.Y' file. The muxer will automatically open the
188 '.U' and '.V' files as required.
195 This muxer computes and prints the MD5 hash of all the input audio
196 and video frames. By default audio frames are converted to signed
197 16-bit raw audio and video frames to raw video before computing the
200 The output of the muxer consists of a single line of the form:
201 MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing
202 the computed MD5 hash.
204 For example to compute the MD5 hash of the input converted to raw
205 audio and video, and store it in the file @file{out.md5}:
207 ffmpeg -i INPUT -f md5 out.md5
210 You can print the MD5 to stdout with the command:
212 ffmpeg -i INPUT -f md5 -
215 See also the @ref{framemd5} muxer.
217 @section MOV/MP4/ISMV
219 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
220 file has all the metadata about all packets stored in one location
221 (written at the end of the file, it can be moved to the start for
222 better playback using the @command{qt-faststart} tool). A fragmented
223 file consists of a number of fragments, where packets and metadata
224 about these packets are stored together. Writing a fragmented
225 file has the advantage that the file is decodable even if the
226 writing is interrupted (while a normal MOV/MP4 is undecodable if
227 it is not properly finished), and it requires less memory when writing
228 very long files (since writing normal MOV/MP4 files stores info about
229 every single packet in memory until the file is closed). The downside
230 is that it is less compatible with other applications.
232 Fragmentation is enabled by setting one of the AVOptions that define
233 how to cut the file into fragments:
236 @item -moov_size @var{bytes}
237 Reserves space for the moov atom at the beginning of the file instead of placing the
238 moov atom at the end. If the space reserved is insufficient, muxing will fail.
239 @item -movflags frag_keyframe
240 Start a new fragment at each video keyframe.
241 @item -frag_duration @var{duration}
242 Create fragments that are @var{duration} microseconds long.
243 @item -frag_size @var{size}
244 Create fragments that contain up to @var{size} bytes of payload data.
245 @item -movflags frag_custom
246 Allow the caller to manually choose when to cut fragments, by
247 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
248 the packets written so far. (This is only useful with other
249 applications integrating libavformat, not from @command{ffmpeg}.)
250 @item -min_frag_duration @var{duration}
251 Don't create fragments that are shorter than @var{duration} microseconds long.
254 If more than one condition is specified, fragments are cut when
255 one of the specified conditions is fulfilled. The exception to this is
256 @code{-min_frag_duration}, which has to be fulfilled for any of the other
259 Additionally, the way the output file is written can be adjusted
260 through a few other options:
263 @item -movflags empty_moov
264 Write an initial moov atom directly at the start of the file, without
265 describing any samples in it. Generally, an mdat/moov pair is written
266 at the start of the file, as a normal MOV/MP4 file, containing only
267 a short portion of the file. With this option set, there is no initial
268 mdat atom, and the moov atom only describes the tracks but has
271 Files written with this option set do not work in QuickTime.
272 This option is implicitly set when writing ismv (Smooth Streaming) files.
273 @item -movflags separate_moof
274 Write a separate moof (movie fragment) atom for each track. Normally,
275 packets for all tracks are written in a moof atom (which is slightly
276 more efficient), but with this option set, the muxer writes one moof/mdat
277 pair for each track, making it easier to separate tracks.
279 This option is implicitly set when writing ismv (Smooth Streaming) files.
282 Smooth Streaming content can be pushed in real time to a publishing
283 point on IIS with this muxer. Example:
285 ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
290 MPEG transport stream muxer.
292 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
294 The muxer options are:
297 @item -mpegts_original_network_id @var{number}
298 Set the original_network_id (default 0x0001). This is unique identifier
299 of a network in DVB. Its main use is in the unique identification of a
300 service through the path Original_Network_ID, Transport_Stream_ID.
301 @item -mpegts_transport_stream_id @var{number}
302 Set the transport_stream_id (default 0x0001). This identifies a
304 @item -mpegts_service_id @var{number}
305 Set the service_id (default 0x0001) also known as program in DVB.
306 @item -mpegts_pmt_start_pid @var{number}
307 Set the first PID for PMT (default 0x1000, max 0x1f00).
308 @item -mpegts_start_pid @var{number}
309 Set the first PID for data packets (default 0x0100, max 0x0f00).
312 The recognized metadata settings in mpegts muxer are @code{service_provider}
313 and @code{service_name}. If they are not set the default for
314 @code{service_provider} is "FFmpeg" and the default for
315 @code{service_name} is "Service01".
318 ffmpeg -i file.mpg -c copy \
319 -mpegts_original_network_id 0x1122 \
320 -mpegts_transport_stream_id 0x3344 \
321 -mpegts_service_id 0x5566 \
322 -mpegts_pmt_start_pid 0x1500 \
323 -mpegts_start_pid 0x150 \
324 -metadata service_provider="Some provider" \
325 -metadata service_name="Some Channel" \
333 This muxer does not generate any output file, it is mainly useful for
334 testing or benchmarking purposes.
336 For example to benchmark decoding with @command{ffmpeg} you can use the
339 ffmpeg -benchmark -i INPUT -f null out.null
342 Note that the above command does not read or write the @file{out.null}
343 file, but specifying the output file is required by the @command{ffmpeg}
346 Alternatively you can write the command as:
348 ffmpeg -benchmark -i INPUT -f null -
353 Matroska container muxer.
355 This muxer implements the matroska and webm container specs.
357 The recognized metadata settings in this muxer are:
361 @item title=@var{title name}
362 Name provided to a single track
367 @item language=@var{language name}
368 Specifies the language of the track in the Matroska languages form
373 @item stereo_mode=@var{mode}
374 Stereo 3D video layout of two views in a single video track
379 Both views are arranged side by side, Left-eye view is on the left
381 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
383 Both views are arranged in top-bottom orientation, Left-eye view is on top
384 @item checkerboard_rl
385 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
386 @item checkerboard_lr
387 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
388 @item row_interleaved_rl
389 Each view is constituted by a row based interleaving, Right-eye view is first row
390 @item row_interleaved_lr
391 Each view is constituted by a row based interleaving, Left-eye view is first row
392 @item col_interleaved_rl
393 Both views are arranged in a column based interleaving manner, Right-eye view is first column
394 @item col_interleaved_lr
395 Both views are arranged in a column based interleaving manner, Left-eye view is first column
396 @item anaglyph_cyan_red
397 All frames are in anaglyph format viewable through red-cyan filters
399 Both views are arranged side by side, Right-eye view is on the left
400 @item anaglyph_green_magenta
401 All frames are in anaglyph format viewable through green-magenta filters
403 Both eyes laced in one Block, Left-eye view is first
405 Both eyes laced in one Block, Right-eye view is first
409 For example a 3D WebM clip can be created using the following command line:
411 ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
414 @section segment, stream_segment, ssegment
416 Basic stream segmenter.
418 The segmenter muxer outputs streams to a number of separate files of nearly
419 fixed duration. Output filename pattern can be set in a fashion similar to
422 @code{stream_segment} is a variant of the muxer used to write to
423 streaming output formats, i.e. which do not require global headers,
424 and is recommended for outputting e.g. to MPEG transport stream segments.
425 @code{ssegment} is a shorter alias for @code{stream_segment}.
427 Every segment starts with a video keyframe, if a video stream is present.
428 Note that if you want accurate splitting for a video file, you need to
429 make the input key frames correspond to the exact splitting times
430 expected by the segmenter, or the segment muxer will start the new
431 segment with the key frame found next after the specified start
434 The segment muxer works best with a single constant frame rate video.
436 Optionally it can generate a flat list of the created segments, one segment
437 per line, by setting the option @var{segment_list}.
439 The segment muxer supports the following options:
442 @item segment_format @var{format}
443 Override the inner container format, by default it is guessed by the filename
445 @item segment_time @var{t}
446 Set segment duration to @var{t} seconds. Default value is 2.
447 @item segment_list @var{name}
448 Generate also a listfile named @var{name}. If not specified no
449 listfile is generated.
450 @item segment_list_size @var{size}
451 Overwrite the listfile once it reaches @var{size} entries. If 0
452 the listfile is never overwritten. Default value is 5.
453 @item segment_wrap @var{limit}
454 Wrap around segment index once it reaches @var{limit}.
457 Some examples follow.
461 To remux the content of file @file{in.mkv} to a list of segments
462 @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
463 generated segments to @file{out.list}:
465 ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut
469 To convert the @file{in.mkv} to TS segments using the @code{libx264}
470 and @code{libfaac} encoders:
472 ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts
478 The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and
479 optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the
480 @code{id3v2_version} option controls which one is used. The legacy ID3v1 tag is
481 not written by default, but may be enabled with the @code{write_id3v1} option.
483 For seekable output the muxer also writes a Xing frame at the beginning, which
484 contains the number of frames in the file. It is useful for computing duration
487 The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures
488 are supplied to the muxer in form of a video stream with a single packet. There
489 can be any number of those streams, each will correspond to a single APIC frame.
490 The stream metadata tags @var{title} and @var{comment} map to APIC
491 @var{description} and @var{picture type} respectively. See
492 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
494 Note that the APIC frames must be written at the beginning, so the muxer will
495 buffer the audio frames until it gets all the pictures. It is therefore advised
496 to provide the pictures as soon as possible to avoid excessive buffering.
500 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
502 ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
505 Attach a picture to an mp3:
507 ffmpeg -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
508 -metadata:s:v comment="Cover (Front)" out.mp3