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  1. @chapter Muxers
  2. @c man begin MUXERS
  3. Muxers are configured elements in FFmpeg which allow writing
  4. multimedia streams to a particular type of file.
  5. When you configure your FFmpeg build, all the supported muxers
  6. are enabled by default. You can list all available muxers using the
  7. configure option @code{--list-muxers}.
  8. You can disable all the muxers with the configure option
  9. @code{--disable-muxers} and selectively enable / disable single muxers
  10. with the options @code{--enable-muxer=@var{MUXER}} /
  11. @code{--disable-muxer=@var{MUXER}}.
  12. The option @code{-muxers} of the ff* tools will display the list of
  13. enabled muxers. Use @code{-formats} to view a combined list of
  14. enabled demuxers and muxers.
  15. A description of some of the currently available muxers follows.
  16. @anchor{aiff}
  17. @section aiff
  18. Audio Interchange File Format muxer.
  19. @subsection Options
  20. It accepts the following options:
  21. @table @option
  22. @item write_id3v2
  23. Enable ID3v2 tags writing when set to 1. Default is 0 (disabled).
  24. @item id3v2_version
  25. Select ID3v2 version to write. Currently only version 3 and 4 (aka.
  26. ID3v2.3 and ID3v2.4) are supported. The default is version 4.
  27. @end table
  28. @anchor{asf}
  29. @section asf
  30. Advanced Systems Format muxer.
  31. Note that Windows Media Audio (wma) and Windows Media Video (wmv) use this
  32. muxer too.
  33. @subsection Options
  34. It accepts the following options:
  35. @table @option
  36. @item packet_size
  37. Set the muxer packet size. By tuning this setting you may reduce data
  38. fragmentation or muxer overhead depending on your source. Default value is
  39. 3200, minimum is 100, maximum is 64k.
  40. @end table
  41. @anchor{avi}
  42. @section avi
  43. Audio Video Interleaved muxer.
  44. @subsection Options
  45. It accepts the following options:
  46. @table @option
  47. @item reserve_index_space
  48. Reserve the specified amount of bytes for the OpenDML master index of each
  49. stream within the file header. By default additional master indexes are
  50. embedded within the data packets if there is no space left in the first master
  51. index and are linked together as a chain of indexes. This index structure can
  52. cause problems for some use cases, e.g. third-party software strictly relying
  53. on the OpenDML index specification or when file seeking is slow. Reserving
  54. enough index space in the file header avoids these problems.
  55. The required index space depends on the output file size and should be about 16
  56. bytes per gigabyte. When this option is omitted or set to zero the necessary
  57. index space is guessed.
  58. @item write_channel_mask
  59. Write the channel layout mask into the audio stream header.
  60. This option is enabled by default. Disabling the channel mask can be useful in
  61. specific scenarios, e.g. when merging multiple audio streams into one for
  62. compatibility with software that only supports a single audio stream in AVI
  63. (see @ref{amerge,,the "amerge" section in the ffmpeg-filters manual,ffmpeg-filters}).
  64. @end table
  65. @anchor{chromaprint}
  66. @section chromaprint
  67. Chromaprint fingerprinter
  68. This muxer feeds audio data to the Chromaprint library, which generates
  69. a fingerprint for the provided audio data. It takes a single signed
  70. native-endian 16-bit raw audio stream.
  71. @subsection Options
  72. @table @option
  73. @item silence_threshold
  74. Threshold for detecting silence, ranges from 0 to 32767. -1 for default
  75. (required for use with the AcoustID service).
  76. @item algorithm
  77. Algorithm index to fingerprint with.
  78. @item fp_format
  79. Format to output the fingerprint as. Accepts the following options:
  80. @table @samp
  81. @item raw
  82. Binary raw fingerprint
  83. @item compressed
  84. Binary compressed fingerprint
  85. @item base64
  86. Base64 compressed fingerprint
  87. @end table
  88. @end table
  89. @anchor{crc}
  90. @section crc
  91. CRC (Cyclic Redundancy Check) testing format.
  92. This muxer computes and prints the Adler-32 CRC of all the input audio
  93. and video frames. By default audio frames are converted to signed
  94. 16-bit raw audio and video frames to raw video before computing the
  95. CRC.
  96. The output of the muxer consists of a single line of the form:
  97. CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
  98. 8 digits containing the CRC for all the decoded input frames.
  99. See also the @ref{framecrc} muxer.
  100. @subsection Examples
  101. For example to compute the CRC of the input, and store it in the file
  102. @file{out.crc}:
  103. @example
  104. ffmpeg -i INPUT -f crc out.crc
  105. @end example
  106. You can print the CRC to stdout with the command:
  107. @example
  108. ffmpeg -i INPUT -f crc -
  109. @end example
  110. You can select the output format of each frame with @command{ffmpeg} by
  111. specifying the audio and video codec and format. For example to
  112. compute the CRC of the input audio converted to PCM unsigned 8-bit
  113. and the input video converted to MPEG-2 video, use the command:
  114. @example
  115. ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
  116. @end example
  117. @section flv
  118. Adobe Flash Video Format muxer.
  119. This muxer accepts the following options:
  120. @table @option
  121. @item flvflags @var{flags}
  122. Possible values:
  123. @table @samp
  124. @item aac_seq_header_detect
  125. Place AAC sequence header based on audio stream data.
  126. @item no_sequence_end
  127. Disable sequence end tag.
  128. @item no_metadata
  129. Disable metadata tag.
  130. @item no_duration_filesize
  131. Disable duration and filesize in metadata when they are equal to zero
  132. at the end of stream. (Be used to non-seekable living stream).
  133. @item add_keyframe_index
  134. Used to facilitate seeking; particularly for HTTP pseudo streaming.
  135. @end table
  136. @end table
  137. @anchor{dash}
  138. @section dash
  139. Dynamic Adaptive Streaming over HTTP (DASH) muxer that creates segments
  140. and manifest files according to the MPEG-DASH standard ISO/IEC 23009-1:2014.
  141. For more information see:
  142. @itemize @bullet
  143. @item
  144. ISO DASH Specification: @url{http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip}
  145. @item
  146. WebM DASH Specification: @url{https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification}
  147. @end itemize
  148. It creates a MPD manifest file and segment files for each stream.
  149. The segment filename might contain pre-defined identifiers used with SegmentTemplate
  150. as defined in section 5.3.9.4.4 of the standard. Available identifiers are "$RepresentationID$",
  151. "$Number$", "$Bandwidth$" and "$Time$".
  152. @example
  153. ffmpeg -re -i <input> -map 0 -map 0 -c:a libfdk_aac -c:v libx264
  154. -b:v:0 800k -b:v:1 300k -s:v:1 320x170 -profile:v:1 baseline
  155. -profile:v:0 main -bf 1 -keyint_min 120 -g 120 -sc_threshold 0
  156. -b_strategy 0 -ar:a:1 22050 -use_timeline 1 -use_template 1
  157. -window_size 5 -adaptation_sets "id=0,streams=v id=1,streams=a"
  158. -f dash /path/to/out.mpd
  159. @end example
  160. @table @option
  161. @item -min_seg_duration @var{microseconds}
  162. This is a deprecated option to set the segment length in microseconds, use @var{seg_duration} instead.
  163. @item -seg_duration @var{duration}
  164. Set the segment length in seconds (fractional value can be set). The value is
  165. treated as average segment duration when @var{use_template} is enabled and
  166. @var{use_timeline} is disabled and as minimum segment duration for all the other
  167. use cases.
  168. @item -window_size @var{size}
  169. Set the maximum number of segments kept in the manifest.
  170. @item -extra_window_size @var{size}
  171. Set the maximum number of segments kept outside of the manifest before removing from disk.
  172. @item -remove_at_exit @var{remove}
  173. Enable (1) or disable (0) removal of all segments when finished.
  174. @item -use_template @var{template}
  175. Enable (1) or disable (0) use of SegmentTemplate instead of SegmentList.
  176. @item -use_timeline @var{timeline}
  177. Enable (1) or disable (0) use of SegmentTimeline in SegmentTemplate.
  178. @item -single_file @var{single_file}
  179. Enable (1) or disable (0) storing all segments in one file, accessed using byte ranges.
  180. @item -single_file_name @var{file_name}
  181. DASH-templated name to be used for baseURL. Implies @var{single_file} set to "1".
  182. @item -init_seg_name @var{init_name}
  183. DASH-templated name to used for the initialization segment. Default is "init-stream$RepresentationID$.m4s"
  184. @item -media_seg_name @var{segment_name}
  185. DASH-templated name to used for the media segments. Default is "chunk-stream$RepresentationID$-$Number%05d$.m4s"
  186. @item -utc_timing_url @var{utc_url}
  187. URL of the page that will return the UTC timestamp in ISO format. Example: "https://time.akamai.com/?iso"
  188. @item method @var{method}
  189. Use the given HTTP method to create output files. Generally set to PUT or POST.
  190. @item -http_user_agent @var{user_agent}
  191. Override User-Agent field in HTTP header. Applicable only for HTTP output.
  192. @item -http_persistent @var{http_persistent}
  193. Use persistent HTTP connections. Applicable only for HTTP output.
  194. @item -hls_playlist @var{hls_playlist}
  195. Generate HLS playlist files as well. The master playlist is generated with the filename master.m3u8.
  196. One media playlist file is generated for each stream with filenames media_0.m3u8, media_1.m3u8, etc.
  197. @item -streaming @var{streaming}
  198. Enable (1) or disable (0) chunk streaming mode of output. In chunk streaming
  199. mode, each frame will be a moof fragment which forms a chunk.
  200. @item -adaptation_sets @var{adaptation_sets}
  201. Assign streams to AdaptationSets. Syntax is "id=x,streams=a,b,c id=y,streams=d,e" with x and y being the IDs
  202. of the adaptation sets and a,b,c,d and e are the indices of the mapped streams.
  203. To map all video (or audio) streams to an AdaptationSet, "v" (or "a") can be used as stream identifier instead of IDs.
  204. When no assignment is defined, this defaults to an AdaptationSet for each stream.
  205. @item -timeout @var{timeout}
  206. Set timeout for socket I/O operations. Applicable only for HTTP output.
  207. @item -index_correction @var{index_correction}
  208. Enable (1) or Disable (0) segment index correction logic. Applicable only when
  209. @var{use_template} is enabled and @var{use_timeline} is disabled.
  210. When enabled, the logic monitors the flow of segment indexes. If a streams's
  211. segment index value is not at the expected real time position, then the logic
  212. corrects that index value.
  213. Typically this logic is needed in live streaming use cases. The network bandwidth
  214. fluctuations are common during long run streaming. Each fluctuation can cause
  215. the segment indexes fall behind the expected real time position.
  216. @item -format_options @var{options_list}
  217. Set container format (mp4/webm) options using a @code{:} separated list of
  218. key=value parameters. Values containing @code{:} special characters must be
  219. escaped.
  220. @item dash_segment_type @var{dash_segment_type}
  221. Possible values:
  222. @item mp4
  223. If this flag is set, the dash segment files will be in in ISOBMFF format. This is the default format.
  224. @item webm
  225. If this flag is set, the dash segment files will be in in WebM format.
  226. @end table
  227. @anchor{framecrc}
  228. @section framecrc
  229. Per-packet CRC (Cyclic Redundancy Check) testing format.
  230. This muxer computes and prints the Adler-32 CRC for each audio
  231. and video packet. By default audio frames are converted to signed
  232. 16-bit raw audio and video frames to raw video before computing the
  233. CRC.
  234. The output of the muxer consists of a line for each audio and video
  235. packet of the form:
  236. @example
  237. @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC}
  238. @end example
  239. @var{CRC} is a hexadecimal number 0-padded to 8 digits containing the
  240. CRC of the packet.
  241. @subsection Examples
  242. For example to compute the CRC of the audio and video frames in
  243. @file{INPUT}, converted to raw audio and video packets, and store it
  244. in the file @file{out.crc}:
  245. @example
  246. ffmpeg -i INPUT -f framecrc out.crc
  247. @end example
  248. To print the information to stdout, use the command:
  249. @example
  250. ffmpeg -i INPUT -f framecrc -
  251. @end example
  252. With @command{ffmpeg}, you can select the output format to which the
  253. audio and video frames are encoded before computing the CRC for each
  254. packet by specifying the audio and video codec. For example, to
  255. compute the CRC of each decoded input audio frame converted to PCM
  256. unsigned 8-bit and of each decoded input video frame converted to
  257. MPEG-2 video, use the command:
  258. @example
  259. ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
  260. @end example
  261. See also the @ref{crc} muxer.
  262. @anchor{framehash}
  263. @section framehash
  264. Per-packet hash testing format.
  265. This muxer computes and prints a cryptographic hash for each audio
  266. and video packet. This can be used for packet-by-packet equality
  267. checks without having to individually do a binary comparison on each.
  268. By default audio frames are converted to signed 16-bit raw audio and
  269. video frames to raw video before computing the hash, but the output
  270. of explicit conversions to other codecs can also be used. It uses the
  271. SHA-256 cryptographic hash function by default, but supports several
  272. other algorithms.
  273. The output of the muxer consists of a line for each audio and video
  274. packet of the form:
  275. @example
  276. @var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{hash}
  277. @end example
  278. @var{hash} is a hexadecimal number representing the computed hash
  279. for the packet.
  280. @table @option
  281. @item hash @var{algorithm}
  282. Use the cryptographic hash function specified by the string @var{algorithm}.
  283. Supported values include @code{MD5}, @code{murmur3}, @code{RIPEMD128},
  284. @code{RIPEMD160}, @code{RIPEMD256}, @code{RIPEMD320}, @code{SHA160},
  285. @code{SHA224}, @code{SHA256} (default), @code{SHA512/224}, @code{SHA512/256},
  286. @code{SHA384}, @code{SHA512}, @code{CRC32} and @code{adler32}.
  287. @end table
  288. @subsection Examples
  289. To compute the SHA-256 hash of the audio and video frames in @file{INPUT},
  290. converted to raw audio and video packets, and store it in the file
  291. @file{out.sha256}:
  292. @example
  293. ffmpeg -i INPUT -f framehash out.sha256
  294. @end example
  295. To print the information to stdout, using the MD5 hash function, use
  296. the command:
  297. @example
  298. ffmpeg -i INPUT -f framehash -hash md5 -
  299. @end example
  300. See also the @ref{hash} muxer.
  301. @anchor{framemd5}
  302. @section framemd5
  303. Per-packet MD5 testing format.
  304. This is a variant of the @ref{framehash} muxer. Unlike that muxer,
  305. it defaults to using the MD5 hash function.
  306. @subsection Examples
  307. To compute the MD5 hash of the audio and video frames in @file{INPUT},
  308. converted to raw audio and video packets, and store it in the file
  309. @file{out.md5}:
  310. @example
  311. ffmpeg -i INPUT -f framemd5 out.md5
  312. @end example
  313. To print the information to stdout, use the command:
  314. @example
  315. ffmpeg -i INPUT -f framemd5 -
  316. @end example
  317. See also the @ref{framehash} and @ref{md5} muxers.
  318. @anchor{gif}
  319. @section gif
  320. Animated GIF muxer.
  321. It accepts the following options:
  322. @table @option
  323. @item loop
  324. Set the number of times to loop the output. Use @code{-1} for no loop, @code{0}
  325. for looping indefinitely (default).
  326. @item final_delay
  327. Force the delay (expressed in centiseconds) after the last frame. Each frame
  328. ends with a delay until the next frame. The default is @code{-1}, which is a
  329. special value to tell the muxer to re-use the previous delay. In case of a
  330. loop, you might want to customize this value to mark a pause for instance.
  331. @end table
  332. For example, to encode a gif looping 10 times, with a 5 seconds delay between
  333. the loops:
  334. @example
  335. ffmpeg -i INPUT -loop 10 -final_delay 500 out.gif
  336. @end example
  337. Note 1: if you wish to extract the frames into separate GIF files, you need to
  338. force the @ref{image2} muxer:
  339. @example
  340. ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif"
  341. @end example
  342. Note 2: the GIF format has a very large time base: the delay between two frames
  343. can therefore not be smaller than one centi second.
  344. @anchor{hash}
  345. @section hash
  346. Hash testing format.
  347. This muxer computes and prints a cryptographic hash of all the input
  348. audio and video frames. This can be used for equality checks without
  349. having to do a complete binary comparison.
  350. By default audio frames are converted to signed 16-bit raw audio and
  351. video frames to raw video before computing the hash, but the output
  352. of explicit conversions to other codecs can also be used. Timestamps
  353. are ignored. It uses the SHA-256 cryptographic hash function by default,
  354. but supports several other algorithms.
  355. The output of the muxer consists of a single line of the form:
  356. @var{algo}=@var{hash}, where @var{algo} is a short string representing
  357. the hash function used, and @var{hash} is a hexadecimal number
  358. representing the computed hash.
  359. @table @option
  360. @item hash @var{algorithm}
  361. Use the cryptographic hash function specified by the string @var{algorithm}.
  362. Supported values include @code{MD5}, @code{murmur3}, @code{RIPEMD128},
  363. @code{RIPEMD160}, @code{RIPEMD256}, @code{RIPEMD320}, @code{SHA160},
  364. @code{SHA224}, @code{SHA256} (default), @code{SHA512/224}, @code{SHA512/256},
  365. @code{SHA384}, @code{SHA512}, @code{CRC32} and @code{adler32}.
  366. @end table
  367. @subsection Examples
  368. To compute the SHA-256 hash of the input converted to raw audio and
  369. video, and store it in the file @file{out.sha256}:
  370. @example
  371. ffmpeg -i INPUT -f hash out.sha256
  372. @end example
  373. To print an MD5 hash to stdout use the command:
  374. @example
  375. ffmpeg -i INPUT -f hash -hash md5 -
  376. @end example
  377. See also the @ref{framehash} muxer.
  378. @anchor{hls}
  379. @section hls
  380. Apple HTTP Live Streaming muxer that segments MPEG-TS according to
  381. the HTTP Live Streaming (HLS) specification.
  382. It creates a playlist file, and one or more segment files. The output filename
  383. specifies the playlist filename.
  384. By default, the muxer creates a file for each segment produced. These files
  385. have the same name as the playlist, followed by a sequential number and a
  386. .ts extension.
  387. Make sure to require a closed GOP when encoding and to set the GOP
  388. size to fit your segment time constraint.
  389. For example, to convert an input file with @command{ffmpeg}:
  390. @example
  391. ffmpeg -i in.mkv -c:v h264 -flags +cgop -g 30 -hls_time 1 out.m3u8
  392. @end example
  393. This example will produce the playlist, @file{out.m3u8}, and segment files:
  394. @file{out0.ts}, @file{out1.ts}, @file{out2.ts}, etc.
  395. See also the @ref{segment} muxer, which provides a more generic and
  396. flexible implementation of a segmenter, and can be used to perform HLS
  397. segmentation.
  398. @subsection Options
  399. This muxer supports the following options:
  400. @table @option
  401. @item hls_init_time @var{seconds}
  402. Set the initial target segment length in seconds. Default value is @var{0}.
  403. Segment will be cut on the next key frame after this time has passed on the first m3u8 list.
  404. After the initial playlist is filled @command{ffmpeg} will cut segments
  405. at duration equal to @code{hls_time}
  406. @item hls_time @var{seconds}
  407. Set the target segment length in seconds. Default value is 2.
  408. Segment will be cut on the next key frame after this time has passed.
  409. @item hls_list_size @var{size}
  410. Set the maximum number of playlist entries. If set to 0 the list file
  411. will contain all the segments. Default value is 5.
  412. @item hls_delete_threshold @var{size}
  413. Set the number of unreferenced segments to keep on disk before @code{hls_flags delete_segments}
  414. deletes them. Increase this to allow continue clients to download segments which
  415. were recently referenced in the playlist. Default value is 1, meaning segments older than
  416. @code{hls_list_size+1} will be deleted.
  417. @item hls_ts_options @var{options_list}
  418. Set output format options using a :-separated list of key=value
  419. parameters. Values containing @code{:} special characters must be
  420. escaped.
  421. @item hls_wrap @var{wrap}
  422. This is a deprecated option, you can use @code{hls_list_size}
  423. and @code{hls_flags delete_segments} instead it
  424. This option is useful to avoid to fill the disk with many segment
  425. files, and limits the maximum number of segment files written to disk
  426. to @var{wrap}.
  427. @item hls_start_number_source
  428. Start the playlist sequence number (@code{#EXT-X-MEDIA-SEQUENCE}) according to the specified source.
  429. Unless @code{hls_flags single_file} is set, it also specifies source of starting sequence numbers of
  430. segment and subtitle filenames. In any case, if @code{hls_flags append_list}
  431. is set and read playlist sequence number is greater than the specified start sequence number,
  432. then that value will be used as start value.
  433. It accepts the following values:
  434. @table @option
  435. @item generic (default)
  436. Set the starting sequence numbers according to @var{start_number} option value.
  437. @item epoch
  438. The start number will be the seconds since epoch (1970-01-01 00:00:00)
  439. @item datetime
  440. The start number will be based on the current date/time as YYYYmmddHHMMSS. e.g. 20161231235759.
  441. @end table
  442. @item start_number @var{number}
  443. Start the playlist sequence number (@code{#EXT-X-MEDIA-SEQUENCE}) from the specified @var{number}
  444. when @var{hls_start_number_source} value is @var{generic}. (This is the default case.)
  445. Unless @code{hls_flags single_file} is set, it also specifies starting sequence numbers of segment and subtitle filenames.
  446. Default value is 0.
  447. @item hls_allow_cache @var{allowcache}
  448. Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments.
  449. @item hls_base_url @var{baseurl}
  450. Append @var{baseurl} to every entry in the playlist.
  451. Useful to generate playlists with absolute paths.
  452. Note that the playlist sequence number must be unique for each segment
  453. and it is not to be confused with the segment filename sequence number
  454. which can be cyclic, for example if the @option{wrap} option is
  455. specified.
  456. @item hls_segment_filename @var{filename}
  457. Set the segment filename. Unless @code{hls_flags single_file} is set,
  458. @var{filename} is used as a string format with the segment number:
  459. @example
  460. ffmpeg -i in.nut -hls_segment_filename 'file%03d.ts' out.m3u8
  461. @end example
  462. This example will produce the playlist, @file{out.m3u8}, and segment files:
  463. @file{file000.ts}, @file{file001.ts}, @file{file002.ts}, etc.
  464. @var{filename} may contain full path or relative path specification,
  465. but only the file name part without any path info will be contained in the m3u8 segment list.
  466. Should a relative path be specified, the path of the created segment
  467. files will be relative to the current working directory.
  468. When use_localtime_mkdir is set, the whole expanded value of @var{filename} will be written into the m3u8 segment list.
  469. When @code{var_stream_map} is set with two or more variant streams, the
  470. @var{filename} pattern must contain the string "%v", this string specifies
  471. the position of variant stream index in the generated segment file names.
  472. @example
  473. ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
  474. -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
  475. -hls_segment_filename 'file_%v_%03d.ts' out_%v.m3u8
  476. @end example
  477. This example will produce the playlists segment file sets:
  478. @file{file_0_000.ts}, @file{file_0_001.ts}, @file{file_0_002.ts}, etc. and
  479. @file{file_1_000.ts}, @file{file_1_001.ts}, @file{file_1_002.ts}, etc.
  480. The string "%v" may be present in the filename or in the last directory name
  481. containing the file. If the string is present in the directory name, then
  482. sub-directories are created after expanding the directory name pattern. This
  483. enables creation of segments corresponding to different variant streams in
  484. subdirectories.
  485. @example
  486. ffmpeg -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
  487. -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
  488. -hls_segment_filename 'vs%v/file_%03d.ts' vs%v/out.m3u8
  489. @end example
  490. This example will produce the playlists segment file sets:
  491. @file{vs0/file_000.ts}, @file{vs0/file_001.ts}, @file{vs0/file_002.ts}, etc. and
  492. @file{vs1/file_000.ts}, @file{vs1/file_001.ts}, @file{vs1/file_002.ts}, etc.
  493. @item use_localtime
  494. Use strftime() on @var{filename} to expand the segment filename with localtime.
  495. The segment number is also available in this mode, but to use it, you need to specify second_level_segment_index
  496. hls_flag and %%d will be the specifier.
  497. @example
  498. ffmpeg -i in.nut -use_localtime 1 -hls_segment_filename 'file-%Y%m%d-%s.ts' out.m3u8
  499. @end example
  500. This example will produce the playlist, @file{out.m3u8}, and segment files:
  501. @file{file-20160215-1455569023.ts}, @file{file-20160215-1455569024.ts}, etc.
  502. Note: On some systems/environments, the @code{%s} specifier is not available. See
  503. @code{strftime()} documentation.
  504. @example
  505. ffmpeg -i in.nut -use_localtime 1 -hls_flags second_level_segment_index -hls_segment_filename 'file-%Y%m%d-%%04d.ts' out.m3u8
  506. @end example
  507. This example will produce the playlist, @file{out.m3u8}, and segment files:
  508. @file{file-20160215-0001.ts}, @file{file-20160215-0002.ts}, etc.
  509. @item use_localtime_mkdir
  510. Used together with -use_localtime, it will create all subdirectories which
  511. is expanded in @var{filename}.
  512. @example
  513. ffmpeg -i in.nut -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename '%Y%m%d/file-%Y%m%d-%s.ts' out.m3u8
  514. @end example
  515. This example will create a directory 201560215 (if it does not exist), and then
  516. produce the playlist, @file{out.m3u8}, and segment files:
  517. @file{20160215/file-20160215-1455569023.ts}, @file{20160215/file-20160215-1455569024.ts}, etc.
  518. @example
  519. ffmpeg -i in.nut -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename '%Y/%m/%d/file-%Y%m%d-%s.ts' out.m3u8
  520. @end example
  521. This example will create a directory hierarchy 2016/02/15 (if any of them do not exist), and then
  522. produce the playlist, @file{out.m3u8}, and segment files:
  523. @file{2016/02/15/file-20160215-1455569023.ts}, @file{2016/02/15/file-20160215-1455569024.ts}, etc.
  524. @item hls_key_info_file @var{key_info_file}
  525. Use the information in @var{key_info_file} for segment encryption. The first
  526. line of @var{key_info_file} specifies the key URI written to the playlist. The
  527. key URL is used to access the encryption key during playback. The second line
  528. specifies the path to the key file used to obtain the key during the encryption
  529. process. The key file is read as a single packed array of 16 octets in binary
  530. format. The optional third line specifies the initialization vector (IV) as a
  531. hexadecimal string to be used instead of the segment sequence number (default)
  532. for encryption. Changes to @var{key_info_file} will result in segment
  533. encryption with the new key/IV and an entry in the playlist for the new key
  534. URI/IV if @code{hls_flags periodic_rekey} is enabled.
  535. Key info file format:
  536. @example
  537. @var{key URI}
  538. @var{key file path}
  539. @var{IV} (optional)
  540. @end example
  541. Example key URIs:
  542. @example
  543. http://server/file.key
  544. /path/to/file.key
  545. file.key
  546. @end example
  547. Example key file paths:
  548. @example
  549. file.key
  550. /path/to/file.key
  551. @end example
  552. Example IV:
  553. @example
  554. 0123456789ABCDEF0123456789ABCDEF
  555. @end example
  556. Key info file example:
  557. @example
  558. http://server/file.key
  559. /path/to/file.key
  560. 0123456789ABCDEF0123456789ABCDEF
  561. @end example
  562. Example shell script:
  563. @example
  564. #!/bin/sh
  565. BASE_URL=$@{1:-'.'@}
  566. openssl rand 16 > file.key
  567. echo $BASE_URL/file.key > file.keyinfo
  568. echo file.key >> file.keyinfo
  569. echo $(openssl rand -hex 16) >> file.keyinfo
  570. ffmpeg -f lavfi -re -i testsrc -c:v h264 -hls_flags delete_segments \
  571. -hls_key_info_file file.keyinfo out.m3u8
  572. @end example
  573. @item -hls_enc @var{enc}
  574. Enable (1) or disable (0) the AES128 encryption.
  575. When enabled every segment generated is encrypted and the encryption key
  576. is saved as @var{playlist name}.key.
  577. @item -hls_enc_key @var{key}
  578. Hex-coded 16byte key to encrypt the segments, by default it
  579. is randomly generated.
  580. @item -hls_enc_key_url @var{keyurl}
  581. If set, @var{keyurl} is prepended instead of @var{baseurl} to the key filename
  582. in the playlist.
  583. @item -hls_enc_iv @var{iv}
  584. Hex-coded 16byte initialization vector for every segment instead
  585. of the autogenerated ones.
  586. @item hls_segment_type @var{flags}
  587. Possible values:
  588. @table @samp
  589. @item mpegts
  590. If this flag is set, the hls segment files will format to mpegts.
  591. the mpegts files is used in all hls versions.
  592. @item fmp4
  593. If this flag is set, the hls segment files will format to fragment mp4 looks like dash.
  594. the fmp4 files is used in hls after version 7.
  595. @end table
  596. @item hls_fmp4_init_filename @var{filename}
  597. set filename to the fragment files header file, default filename is @file{init.mp4}.
  598. When @code{var_stream_map} is set with two or more variant streams, the
  599. @var{filename} pattern must contain the string "%v", this string specifies
  600. the position of variant stream index in the generated init file names.
  601. The string "%v" may be present in the filename or in the last directory name
  602. containing the file. If the string is present in the directory name, then
  603. sub-directories are created after expanding the directory name pattern. This
  604. enables creation of init files corresponding to different variant streams in
  605. subdirectories.
  606. @item hls_flags @var{flags}
  607. Possible values:
  608. @table @samp
  609. @item single_file
  610. If this flag is set, the muxer will store all segments in a single MPEG-TS
  611. file, and will use byte ranges in the playlist. HLS playlists generated with
  612. this way will have the version number 4.
  613. For example:
  614. @example
  615. ffmpeg -i in.nut -hls_flags single_file out.m3u8
  616. @end example
  617. Will produce the playlist, @file{out.m3u8}, and a single segment file,
  618. @file{out.ts}.
  619. @item delete_segments
  620. Segment files removed from the playlist are deleted after a period of time
  621. equal to the duration of the segment plus the duration of the playlist.
  622. @item append_list
  623. Append new segments into the end of old segment list,
  624. and remove the @code{#EXT-X-ENDLIST} from the old segment list.
  625. @item round_durations
  626. Round the duration info in the playlist file segment info to integer
  627. values, instead of using floating point.
  628. @item discont_start
  629. Add the @code{#EXT-X-DISCONTINUITY} tag to the playlist, before the
  630. first segment's information.
  631. @item omit_endlist
  632. Do not append the @code{EXT-X-ENDLIST} tag at the end of the playlist.
  633. @item periodic_rekey
  634. The file specified by @code{hls_key_info_file} will be checked periodically and
  635. detect updates to the encryption info. Be sure to replace this file atomically,
  636. including the file containing the AES encryption key.
  637. @item independent_segments
  638. Add the @code{#EXT-X-INDEPENDENT-SEGMENTS} to playlists that has video segments
  639. and when all the segments of that playlist are guaranteed to start with a Key frame.
  640. @item split_by_time
  641. Allow segments to start on frames other than keyframes. This improves
  642. behavior on some players when the time between keyframes is inconsistent,
  643. but may make things worse on others, and can cause some oddities during
  644. seeking. This flag should be used with the @code{hls_time} option.
  645. @item program_date_time
  646. Generate @code{EXT-X-PROGRAM-DATE-TIME} tags.
  647. @item second_level_segment_index
  648. Makes it possible to use segment indexes as %%d in hls_segment_filename expression
  649. besides date/time values when use_localtime is on.
  650. To get fixed width numbers with trailing zeroes, %%0xd format is available where x is the required width.
  651. @item second_level_segment_size
  652. Makes it possible to use segment sizes (counted in bytes) as %%s in hls_segment_filename
  653. expression besides date/time values when use_localtime is on.
  654. To get fixed width numbers with trailing zeroes, %%0xs format is available where x is the required width.
  655. @item second_level_segment_duration
  656. Makes it possible to use segment duration (calculated in microseconds) as %%t in hls_segment_filename
  657. expression besides date/time values when use_localtime is on.
  658. To get fixed width numbers with trailing zeroes, %%0xt format is available where x is the required width.
  659. @example
  660. ffmpeg -i sample.mpeg \
  661. -f hls -hls_time 3 -hls_list_size 5 \
  662. -hls_flags second_level_segment_index+second_level_segment_size+second_level_segment_duration \
  663. -use_localtime 1 -use_localtime_mkdir 1 -hls_segment_filename "segment_%Y%m%d%H%M%S_%%04d_%%08s_%%013t.ts" stream.m3u8
  664. @end example
  665. This will produce segments like this:
  666. @file{segment_20170102194334_0003_00122200_0000003000000.ts}, @file{segment_20170102194334_0004_00120072_0000003000000.ts} etc.
  667. @item temp_file
  668. Write segment data to filename.tmp and rename to filename only once the segment is complete. A webserver
  669. serving up segments can be configured to reject requests to *.tmp to prevent access to in-progress segments
  670. before they have been added to the m3u8 playlist.
  671. @end table
  672. @item hls_playlist_type event
  673. Emit @code{#EXT-X-PLAYLIST-TYPE:EVENT} in the m3u8 header. Forces
  674. @option{hls_list_size} to 0; the playlist can only be appended to.
  675. @item hls_playlist_type vod
  676. Emit @code{#EXT-X-PLAYLIST-TYPE:VOD} in the m3u8 header. Forces
  677. @option{hls_list_size} to 0; the playlist must not change.
  678. @item method
  679. Use the given HTTP method to create the hls files.
  680. @example
  681. ffmpeg -re -i in.ts -f hls -method PUT http://example.com/live/out.m3u8
  682. @end example
  683. This example will upload all the mpegts segment files to the HTTP
  684. server using the HTTP PUT method, and update the m3u8 files every
  685. @code{refresh} times using the same method.
  686. Note that the HTTP server must support the given method for uploading
  687. files.
  688. @item http_user_agent
  689. Override User-Agent field in HTTP header. Applicable only for HTTP output.
  690. @item var_stream_map
  691. Map string which specifies how to group the audio, video and subtitle streams
  692. into different variant streams. The variant stream groups are separated
  693. by space.
  694. Expected string format is like this "a:0,v:0 a:1,v:1 ....". Here a:, v:, s: are
  695. the keys to specify audio, video and subtitle streams respectively.
  696. Allowed values are 0 to 9 (limited just based on practical usage).
  697. When there are two or more variant streams, the output filename pattern must
  698. contain the string "%v", this string specifies the position of variant stream
  699. index in the output media playlist filenames. The string "%v" may be present in
  700. the filename or in the last directory name containing the file. If the string is
  701. present in the directory name, then sub-directories are created after expanding
  702. the directory name pattern. This enables creation of variant streams in
  703. subdirectories.
  704. @example
  705. ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
  706. -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
  707. http://example.com/live/out_%v.m3u8
  708. @end example
  709. This example creates two hls variant streams. The first variant stream will
  710. contain video stream of bitrate 1000k and audio stream of bitrate 64k and the
  711. second variant stream will contain video stream of bitrate 256k and audio
  712. stream of bitrate 32k. Here, two media playlist with file names out_0.m3u8 and
  713. out_1.m3u8 will be created.
  714. @example
  715. ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k \
  716. -map 0:v -map 0:a -map 0:v -f hls -var_stream_map "v:0 a:0 v:1" \
  717. http://example.com/live/out_%v.m3u8
  718. @end example
  719. This example creates three hls variant streams. The first variant stream will
  720. be a video only stream with video bitrate 1000k, the second variant stream will
  721. be an audio only stream with bitrate 64k and the third variant stream will be a
  722. video only stream with bitrate 256k. Here, three media playlist with file names
  723. out_0.m3u8, out_1.m3u8 and out_2.m3u8 will be created.
  724. @example
  725. ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
  726. -map 0:v -map 0:a -map 0:v -map 0:a -f hls -var_stream_map "v:0,a:0 v:1,a:1" \
  727. http://example.com/live/vs_%v/out.m3u8
  728. @end example
  729. This example creates the variant streams in subdirectories. Here, the first
  730. media playlist is created at @file{http://example.com/live/vs_0/out.m3u8} and
  731. the second one at @file{http://example.com/live/vs_1/out.m3u8}.
  732. @example
  733. ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k \
  734. -map 0:a -map 0:a -map 0:v -map 0:v -f hls \
  735. -var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
  736. -master_pl_name master.m3u8 \
  737. http://example.com/live/out_%v.m3u8
  738. @end example
  739. This example creates two audio only and two video only variant streams. In
  740. addition to the #EXT-X-STREAM-INF tag for each variant stream in the master
  741. playlist, #EXT-X-MEDIA tag is also added for the two audio only variant streams
  742. and they are mapped to the two video only variant streams with audio group names
  743. 'aud_low' and 'aud_high'.
  744. By default, a single hls variant containing all the encoded streams is created.
  745. @item cc_stream_map
  746. Map string which specifies different closed captions groups and their
  747. attributes. The closed captions stream groups are separated by space.
  748. Expected string format is like this
  749. "ccgroup:<group name>,instreamid:<INSTREAM-ID>,language:<language code> ....".
  750. 'ccgroup' and 'instreamid' are mandatory attributes. 'language' is an optional
  751. attribute.
  752. The closed captions groups configured using this option are mapped to different
  753. variant streams by providing the same 'ccgroup' name in the
  754. @code{var_stream_map} string. If @code{var_stream_map} is not set, then the
  755. first available ccgroup in @code{cc_stream_map} is mapped to the output variant
  756. stream. The examples for these two use cases are given below.
  757. @example
  758. ffmpeg -re -i in.ts -b:v 1000k -b:a 64k -a53cc 1 -f hls \
  759. -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en" \
  760. -master_pl_name master.m3u8 \
  761. http://example.com/live/out.m3u8
  762. @end example
  763. This example adds @code{#EXT-X-MEDIA} tag with @code{TYPE=CLOSED-CAPTIONS} in
  764. the master playlist with group name 'cc', langauge 'en' (english) and
  765. INSTREAM-ID 'CC1'. Also, it adds @code{CLOSED-CAPTIONS} attribute with group
  766. name 'cc' for the output variant stream.
  767. @example
  768. ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
  769. -a53cc:0 1 -a53cc:1 1\
  770. -map 0:v -map 0:a -map 0:v -map 0:a -f hls \
  771. -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en ccgroup:cc,instreamid:CC2,language:sp" \
  772. -var_stream_map "v:0,a:0,ccgroup:cc v:1,a:1,ccgroup:cc" \
  773. -master_pl_name master.m3u8 \
  774. http://example.com/live/out_%v.m3u8
  775. @end example
  776. This example adds two @code{#EXT-X-MEDIA} tags with @code{TYPE=CLOSED-CAPTIONS} in
  777. the master playlist for the INSTREAM-IDs 'CC1' and 'CC2'. Also, it adds
  778. @code{CLOSED-CAPTIONS} attribute with group name 'cc' for the two output variant
  779. streams.
  780. @item master_pl_name
  781. Create HLS master playlist with the given name.
  782. @example
  783. ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 http://example.com/live/out.m3u8
  784. @end example
  785. This example creates HLS master playlist with name master.m3u8 and it is
  786. published at http://example.com/live/
  787. @item master_pl_publish_rate
  788. Publish master play list repeatedly every after specified number of segment intervals.
  789. @example
  790. ffmpeg -re -i in.ts -f hls -master_pl_name master.m3u8 \
  791. -hls_time 2 -master_pl_publish_rate 30 http://example.com/live/out.m3u8
  792. @end example
  793. This example creates HLS master playlist with name master.m3u8 and keep
  794. publishing it repeatedly every after 30 segments i.e. every after 60s.
  795. @item http_persistent
  796. Use persistent HTTP connections. Applicable only for HTTP output.
  797. @item timeout
  798. Set timeout for socket I/O operations. Applicable only for HTTP output.
  799. @end table
  800. @anchor{ico}
  801. @section ico
  802. ICO file muxer.
  803. Microsoft's icon file format (ICO) has some strict limitations that should be noted:
  804. @itemize
  805. @item
  806. Size cannot exceed 256 pixels in any dimension
  807. @item
  808. Only BMP and PNG images can be stored
  809. @item
  810. If a BMP image is used, it must be one of the following pixel formats:
  811. @example
  812. BMP Bit Depth FFmpeg Pixel Format
  813. 1bit pal8
  814. 4bit pal8
  815. 8bit pal8
  816. 16bit rgb555le
  817. 24bit bgr24
  818. 32bit bgra
  819. @end example
  820. @item
  821. If a BMP image is used, it must use the BITMAPINFOHEADER DIB header
  822. @item
  823. If a PNG image is used, it must use the rgba pixel format
  824. @end itemize
  825. @anchor{image2}
  826. @section image2
  827. Image file muxer.
  828. The image file muxer writes video frames to image files.
  829. The output filenames are specified by a pattern, which can be used to
  830. produce sequentially numbered series of files.
  831. The pattern may contain the string "%d" or "%0@var{N}d", this string
  832. specifies the position of the characters representing a numbering in
  833. the filenames. If the form "%0@var{N}d" is used, the string
  834. representing the number in each filename is 0-padded to @var{N}
  835. digits. The literal character '%' can be specified in the pattern with
  836. the string "%%".
  837. If the pattern contains "%d" or "%0@var{N}d", the first filename of
  838. the file list specified will contain the number 1, all the following
  839. numbers will be sequential.
  840. The pattern may contain a suffix which is used to automatically
  841. determine the format of the image files to write.
  842. For example the pattern "img-%03d.bmp" will specify a sequence of
  843. filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
  844. @file{img-010.bmp}, etc.
  845. The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
  846. form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
  847. etc.
  848. @subsection Examples
  849. The following example shows how to use @command{ffmpeg} for creating a
  850. sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
  851. taking one image every second from the input video:
  852. @example
  853. ffmpeg -i in.avi -vsync cfr -r 1 -f image2 'img-%03d.jpeg'
  854. @end example
  855. Note that with @command{ffmpeg}, if the format is not specified with the
  856. @code{-f} option and the output filename specifies an image file
  857. format, the image2 muxer is automatically selected, so the previous
  858. command can be written as:
  859. @example
  860. ffmpeg -i in.avi -vsync cfr -r 1 'img-%03d.jpeg'
  861. @end example
  862. Note also that the pattern must not necessarily contain "%d" or
  863. "%0@var{N}d", for example to create a single image file
  864. @file{img.jpeg} from the start of the input video you can employ the command:
  865. @example
  866. ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg
  867. @end example
  868. The @option{strftime} option allows you to expand the filename with
  869. date and time information. Check the documentation of
  870. the @code{strftime()} function for the syntax.
  871. For example to generate image files from the @code{strftime()}
  872. "%Y-%m-%d_%H-%M-%S" pattern, the following @command{ffmpeg} command
  873. can be used:
  874. @example
  875. ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"
  876. @end example
  877. You can set the file name with current frame's PTS:
  878. @example
  879. ffmpeg -f v4l2 -r 1 -i /dev/video0 -copyts -f image2 -frame_pts true %d.jpg"
  880. @end example
  881. @subsection Options
  882. @table @option
  883. @item frame_pts
  884. If set to 1, expand the filename with pts from pkt->pts.
  885. Default value is 0.
  886. @item start_number
  887. Start the sequence from the specified number. Default value is 1.
  888. @item update
  889. If set to 1, the filename will always be interpreted as just a
  890. filename, not a pattern, and the corresponding file will be continuously
  891. overwritten with new images. Default value is 0.
  892. @item strftime
  893. If set to 1, expand the filename with date and time information from
  894. @code{strftime()}. Default value is 0.
  895. @end table
  896. The image muxer supports the .Y.U.V image file format. This format is
  897. special in that that each image frame consists of three files, for
  898. each of the YUV420P components. To read or write this image file format,
  899. specify the name of the '.Y' file. The muxer will automatically open the
  900. '.U' and '.V' files as required.
  901. @section matroska
  902. Matroska container muxer.
  903. This muxer implements the matroska and webm container specs.
  904. @subsection Metadata
  905. The recognized metadata settings in this muxer are:
  906. @table @option
  907. @item title
  908. Set title name provided to a single track.
  909. @item language
  910. Specify the language of the track in the Matroska languages form.
  911. The language can be either the 3 letters bibliographic ISO-639-2 (ISO
  912. 639-2/B) form (like "fre" for French), or a language code mixed with a
  913. country code for specialities in languages (like "fre-ca" for Canadian
  914. French).
  915. @item stereo_mode
  916. Set stereo 3D video layout of two views in a single video track.
  917. The following values are recognized:
  918. @table @samp
  919. @item mono
  920. video is not stereo
  921. @item left_right
  922. Both views are arranged side by side, Left-eye view is on the left
  923. @item bottom_top
  924. Both views are arranged in top-bottom orientation, Left-eye view is at bottom
  925. @item top_bottom
  926. Both views are arranged in top-bottom orientation, Left-eye view is on top
  927. @item checkerboard_rl
  928. Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
  929. @item checkerboard_lr
  930. Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
  931. @item row_interleaved_rl
  932. Each view is constituted by a row based interleaving, Right-eye view is first row
  933. @item row_interleaved_lr
  934. Each view is constituted by a row based interleaving, Left-eye view is first row
  935. @item col_interleaved_rl
  936. Both views are arranged in a column based interleaving manner, Right-eye view is first column
  937. @item col_interleaved_lr
  938. Both views are arranged in a column based interleaving manner, Left-eye view is first column
  939. @item anaglyph_cyan_red
  940. All frames are in anaglyph format viewable through red-cyan filters
  941. @item right_left
  942. Both views are arranged side by side, Right-eye view is on the left
  943. @item anaglyph_green_magenta
  944. All frames are in anaglyph format viewable through green-magenta filters
  945. @item block_lr
  946. Both eyes laced in one Block, Left-eye view is first
  947. @item block_rl
  948. Both eyes laced in one Block, Right-eye view is first
  949. @end table
  950. @end table
  951. For example a 3D WebM clip can be created using the following command line:
  952. @example
  953. ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm
  954. @end example
  955. @subsection Options
  956. This muxer supports the following options:
  957. @table @option
  958. @item reserve_index_space
  959. By default, this muxer writes the index for seeking (called cues in Matroska
  960. terms) at the end of the file, because it cannot know in advance how much space
  961. to leave for the index at the beginning of the file. However for some use cases
  962. -- e.g. streaming where seeking is possible but slow -- it is useful to put the
  963. index at the beginning of the file.
  964. If this option is set to a non-zero value, the muxer will reserve a given amount
  965. of space in the file header and then try to write the cues there when the muxing
  966. finishes. If the available space does not suffice, muxing will fail. A safe size
  967. for most use cases should be about 50kB per hour of video.
  968. Note that cues are only written if the output is seekable and this option will
  969. have no effect if it is not.
  970. @end table
  971. @anchor{md5}
  972. @section md5
  973. MD5 testing format.
  974. This is a variant of the @ref{hash} muxer. Unlike that muxer, it
  975. defaults to using the MD5 hash function.
  976. @subsection Examples
  977. To compute the MD5 hash of the input converted to raw
  978. audio and video, and store it in the file @file{out.md5}:
  979. @example
  980. ffmpeg -i INPUT -f md5 out.md5
  981. @end example
  982. You can print the MD5 to stdout with the command:
  983. @example
  984. ffmpeg -i INPUT -f md5 -
  985. @end example
  986. See also the @ref{hash} and @ref{framemd5} muxers.
  987. @section mov, mp4, ismv
  988. MOV/MP4/ISMV (Smooth Streaming) muxer.
  989. The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
  990. file has all the metadata about all packets stored in one location
  991. (written at the end of the file, it can be moved to the start for
  992. better playback by adding @var{faststart} to the @var{movflags}, or
  993. using the @command{qt-faststart} tool). A fragmented
  994. file consists of a number of fragments, where packets and metadata
  995. about these packets are stored together. Writing a fragmented
  996. file has the advantage that the file is decodable even if the
  997. writing is interrupted (while a normal MOV/MP4 is undecodable if
  998. it is not properly finished), and it requires less memory when writing
  999. very long files (since writing normal MOV/MP4 files stores info about
  1000. every single packet in memory until the file is closed). The downside
  1001. is that it is less compatible with other applications.
  1002. @subsection Options
  1003. Fragmentation is enabled by setting one of the AVOptions that define
  1004. how to cut the file into fragments:
  1005. @table @option
  1006. @item -moov_size @var{bytes}
  1007. Reserves space for the moov atom at the beginning of the file instead of placing the
  1008. moov atom at the end. If the space reserved is insufficient, muxing will fail.
  1009. @item -movflags frag_keyframe
  1010. Start a new fragment at each video keyframe.
  1011. @item -frag_duration @var{duration}
  1012. Create fragments that are @var{duration} microseconds long.
  1013. @item -frag_size @var{size}
  1014. Create fragments that contain up to @var{size} bytes of payload data.
  1015. @item -movflags frag_custom
  1016. Allow the caller to manually choose when to cut fragments, by
  1017. calling @code{av_write_frame(ctx, NULL)} to write a fragment with
  1018. the packets written so far. (This is only useful with other
  1019. applications integrating libavformat, not from @command{ffmpeg}.)
  1020. @item -min_frag_duration @var{duration}
  1021. Don't create fragments that are shorter than @var{duration} microseconds long.
  1022. @end table
  1023. If more than one condition is specified, fragments are cut when
  1024. one of the specified conditions is fulfilled. The exception to this is
  1025. @code{-min_frag_duration}, which has to be fulfilled for any of the other
  1026. conditions to apply.
  1027. Additionally, the way the output file is written can be adjusted
  1028. through a few other options:
  1029. @table @option
  1030. @item -movflags empty_moov
  1031. Write an initial moov atom directly at the start of the file, without
  1032. describing any samples in it. Generally, an mdat/moov pair is written
  1033. at the start of the file, as a normal MOV/MP4 file, containing only
  1034. a short portion of the file. With this option set, there is no initial
  1035. mdat atom, and the moov atom only describes the tracks but has
  1036. a zero duration.
  1037. This option is implicitly set when writing ismv (Smooth Streaming) files.
  1038. @item -movflags separate_moof
  1039. Write a separate moof (movie fragment) atom for each track. Normally,
  1040. packets for all tracks are written in a moof atom (which is slightly
  1041. more efficient), but with this option set, the muxer writes one moof/mdat
  1042. pair for each track, making it easier to separate tracks.
  1043. This option is implicitly set when writing ismv (Smooth Streaming) files.
  1044. @item -movflags faststart
  1045. Run a second pass moving the index (moov atom) to the beginning of the file.
  1046. This operation can take a while, and will not work in various situations such
  1047. as fragmented output, thus it is not enabled by default.
  1048. @item -movflags rtphint
  1049. Add RTP hinting tracks to the output file.
  1050. @item -movflags disable_chpl
  1051. Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
  1052. and a QuickTime chapter track are written to the file. With this option
  1053. set, only the QuickTime chapter track will be written. Nero chapters can
  1054. cause failures when the file is reprocessed with certain tagging programs, like
  1055. mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.
  1056. @item -movflags omit_tfhd_offset
  1057. Do not write any absolute base_data_offset in tfhd atoms. This avoids
  1058. tying fragments to absolute byte positions in the file/streams.
  1059. @item -movflags default_base_moof
  1060. Similarly to the omit_tfhd_offset, this flag avoids writing the
  1061. absolute base_data_offset field in tfhd atoms, but does so by using
  1062. the new default-base-is-moof flag instead. This flag is new from
  1063. 14496-12:2012. This may make the fragments easier to parse in certain
  1064. circumstances (avoiding basing track fragment location calculations
  1065. on the implicit end of the previous track fragment).
  1066. @item -write_tmcd
  1067. Specify @code{on} to force writing a timecode track, @code{off} to disable it
  1068. and @code{auto} to write a timecode track only for mov and mp4 output (default).
  1069. @item -movflags negative_cts_offsets
  1070. Enables utilization of version 1 of the CTTS box, in which the CTS offsets can
  1071. be negative. This enables the initial sample to have DTS/CTS of zero, and
  1072. reduces the need for edit lists for some cases such as video tracks with
  1073. B-frames. Additionally, eases conformance with the DASH-IF interoperability
  1074. guidelines.
  1075. @end table
  1076. @subsection Example
  1077. Smooth Streaming content can be pushed in real time to a publishing
  1078. point on IIS with this muxer. Example:
  1079. @example
  1080. ffmpeg -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
  1081. @end example
  1082. @subsection Audible AAX
  1083. Audible AAX files are encrypted M4B files, and they can be decrypted by specifying a 4 byte activation secret.
  1084. @example
  1085. ffmpeg -activation_bytes 1CEB00DA -i test.aax -vn -c:a copy output.mp4
  1086. @end example
  1087. @section mp3
  1088. The MP3 muxer writes a raw MP3 stream with the following optional features:
  1089. @itemize @bullet
  1090. @item
  1091. An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
  1092. 2.4 are supported, the @code{id3v2_version} private option controls which one is
  1093. used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header
  1094. completely.
  1095. The muxer supports writing attached pictures (APIC frames) to the ID3v2 header.
  1096. The pictures are supplied to the muxer in form of a video stream with a single
  1097. packet. There can be any number of those streams, each will correspond to a
  1098. single APIC frame. The stream metadata tags @var{title} and @var{comment} map
  1099. to APIC @var{description} and @var{picture type} respectively. See
  1100. @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
  1101. Note that the APIC frames must be written at the beginning, so the muxer will
  1102. buffer the audio frames until it gets all the pictures. It is therefore advised
  1103. to provide the pictures as soon as possible to avoid excessive buffering.
  1104. @item
  1105. A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
  1106. default, but will be written only if the output is seekable. The
  1107. @code{write_xing} private option can be used to disable it. The frame contains
  1108. various information that may be useful to the decoder, like the audio duration
  1109. or encoder delay.
  1110. @item
  1111. A legacy ID3v1 tag at the end of the file (disabled by default). It may be
  1112. enabled with the @code{write_id3v1} private option, but as its capabilities are
  1113. very limited, its usage is not recommended.
  1114. @end itemize
  1115. Examples:
  1116. Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
  1117. @example
  1118. ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
  1119. @end example
  1120. To attach a picture to an mp3 file select both the audio and the picture stream
  1121. with @code{map}:
  1122. @example
  1123. ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
  1124. -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3
  1125. @end example
  1126. Write a "clean" MP3 without any extra features:
  1127. @example
  1128. ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
  1129. @end example
  1130. @section mpegts
  1131. MPEG transport stream muxer.
  1132. This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
  1133. The recognized metadata settings in mpegts muxer are @code{service_provider}
  1134. and @code{service_name}. If they are not set the default for
  1135. @code{service_provider} is @samp{FFmpeg} and the default for
  1136. @code{service_name} is @samp{Service01}.
  1137. @subsection Options
  1138. The muxer options are:
  1139. @table @option
  1140. @item mpegts_transport_stream_id @var{integer}
  1141. Set the @samp{transport_stream_id}. This identifies a transponder in DVB.
  1142. Default is @code{0x0001}.
  1143. @item mpegts_original_network_id @var{integer}
  1144. Set the @samp{original_network_id}. This is unique identifier of a
  1145. network in DVB. Its main use is in the unique identification of a service
  1146. through the path @samp{Original_Network_ID, Transport_Stream_ID}. Default
  1147. is @code{0x0001}.
  1148. @item mpegts_service_id @var{integer}
  1149. Set the @samp{service_id}, also known as program in DVB. Default is
  1150. @code{0x0001}.
  1151. @item mpegts_service_type @var{integer}
  1152. Set the program @samp{service_type}. Default is @code{digital_tv}.
  1153. Accepts the following options:
  1154. @table @samp
  1155. @item hex_value
  1156. Any hexdecimal value between @code{0x01} to @code{0xff} as defined in
  1157. ETSI 300 468.
  1158. @item digital_tv
  1159. Digital TV service.
  1160. @item digital_radio
  1161. Digital Radio service.
  1162. @item teletext
  1163. Teletext service.
  1164. @item advanced_codec_digital_radio
  1165. Advanced Codec Digital Radio service.
  1166. @item mpeg2_digital_hdtv
  1167. MPEG2 Digital HDTV service.
  1168. @item advanced_codec_digital_sdtv
  1169. Advanced Codec Digital SDTV service.
  1170. @item advanced_codec_digital_hdtv
  1171. Advanced Codec Digital HDTV service.
  1172. @end table
  1173. @item mpegts_pmt_start_pid @var{integer}
  1174. Set the first PID for PMT. Default is @code{0x1000}. Max is @code{0x1f00}.
  1175. @item mpegts_start_pid @var{integer}
  1176. Set the first PID for data packets. Default is @code{0x0100}. Max is
  1177. @code{0x0f00}.
  1178. @item mpegts_m2ts_mode @var{boolean}
  1179. Enable m2ts mode if set to @code{1}. Default value is @code{-1} which
  1180. disables m2ts mode.
  1181. @item muxrate @var{integer}
  1182. Set a constant muxrate. Default is VBR.
  1183. @item pes_payload_size @var{integer}
  1184. Set minimum PES packet payload in bytes. Default is @code{2930}.
  1185. @item mpegts_flags @var{flags}
  1186. Set mpegts flags. Accepts the following options:
  1187. @table @samp
  1188. @item resend_headers
  1189. Reemit PAT/PMT before writing the next packet.
  1190. @item latm
  1191. Use LATM packetization for AAC.
  1192. @item pat_pmt_at_frames
  1193. Reemit PAT and PMT at each video frame.
  1194. @item system_b
  1195. Conform to System B (DVB) instead of System A (ATSC).
  1196. @item initial_discontinuity
  1197. Mark the initial packet of each stream as discontinuity.
  1198. @end table
  1199. @item resend_headers @var{integer}
  1200. Reemit PAT/PMT before writing the next packet. This option is deprecated:
  1201. use @option{mpegts_flags} instead.
  1202. @item mpegts_copyts @var{boolean}
  1203. Preserve original timestamps, if value is set to @code{1}. Default value
  1204. is @code{-1}, which results in shifting timestamps so that they start from 0.
  1205. @item omit_video_pes_length @var{boolean}
  1206. Omit the PES packet length for video packets. Default is @code{1} (true).
  1207. @item pcr_period @var{integer}
  1208. Override the default PCR retransmission time in milliseconds. Ignored if
  1209. variable muxrate is selected. Default is @code{20}.
  1210. @item pat_period @var{double}
  1211. Maximum time in seconds between PAT/PMT tables.
  1212. @item sdt_period @var{double}
  1213. Maximum time in seconds between SDT tables.
  1214. @item tables_version @var{integer}
  1215. Set PAT, PMT and SDT version (default @code{0}, valid values are from 0 to 31, inclusively).
  1216. This option allows updating stream structure so that standard consumer may
  1217. detect the change. To do so, reopen output @code{AVFormatContext} (in case of API
  1218. usage) or restart @command{ffmpeg} instance, cyclically changing
  1219. @option{tables_version} value:
  1220. @example
  1221. ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
  1222. ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
  1223. ...
  1224. ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
  1225. ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
  1226. ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
  1227. ...
  1228. @end example
  1229. @end table
  1230. @subsection Example
  1231. @example
  1232. ffmpeg -i file.mpg -c copy \
  1233. -mpegts_original_network_id 0x1122 \
  1234. -mpegts_transport_stream_id 0x3344 \
  1235. -mpegts_service_id 0x5566 \
  1236. -mpegts_pmt_start_pid 0x1500 \
  1237. -mpegts_start_pid 0x150 \
  1238. -metadata service_provider="Some provider" \
  1239. -metadata service_name="Some Channel" \
  1240. out.ts
  1241. @end example
  1242. @section mxf, mxf_d10
  1243. MXF muxer.
  1244. @subsection Options
  1245. The muxer options are:
  1246. @table @option
  1247. @item store_user_comments @var{bool}
  1248. Set if user comments should be stored if available or never.
  1249. IRT D-10 does not allow user comments. The default is thus to write them for
  1250. mxf but not for mxf_d10
  1251. @end table
  1252. @section null
  1253. Null muxer.
  1254. This muxer does not generate any output file, it is mainly useful for
  1255. testing or benchmarking purposes.
  1256. For example to benchmark decoding with @command{ffmpeg} you can use the
  1257. command:
  1258. @example
  1259. ffmpeg -benchmark -i INPUT -f null out.null
  1260. @end example
  1261. Note that the above command does not read or write the @file{out.null}
  1262. file, but specifying the output file is required by the @command{ffmpeg}
  1263. syntax.
  1264. Alternatively you can write the command as:
  1265. @example
  1266. ffmpeg -benchmark -i INPUT -f null -
  1267. @end example
  1268. @section nut
  1269. @table @option
  1270. @item -syncpoints @var{flags}
  1271. Change the syncpoint usage in nut:
  1272. @table @option
  1273. @item @var{default} use the normal low-overhead seeking aids.
  1274. @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
  1275. Use of this option is not recommended, as the resulting files are very damage
  1276. sensitive and seeking is not possible. Also in general the overhead from
  1277. syncpoints is negligible. Note, -@code{write_index} 0 can be used to disable
  1278. all growing data tables, allowing to mux endless streams with limited memory
  1279. and without these disadvantages.
  1280. @item @var{timestamped} extend the syncpoint with a wallclock field.
  1281. @end table
  1282. The @var{none} and @var{timestamped} flags are experimental.
  1283. @item -write_index @var{bool}
  1284. Write index at the end, the default is to write an index.
  1285. @end table
  1286. @example
  1287. ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor
  1288. @end example
  1289. @section ogg
  1290. Ogg container muxer.
  1291. @table @option
  1292. @item -page_duration @var{duration}
  1293. Preferred page duration, in microseconds. The muxer will attempt to create
  1294. pages that are approximately @var{duration} microseconds long. This allows the
  1295. user to compromise between seek granularity and container overhead. The default
  1296. is 1 second. A value of 0 will fill all segments, making pages as large as
  1297. possible. A value of 1 will effectively use 1 packet-per-page in most
  1298. situations, giving a small seek granularity at the cost of additional container
  1299. overhead.
  1300. @item -serial_offset @var{value}
  1301. Serial value from which to set the streams serial number.
  1302. Setting it to different and sufficiently large values ensures that the produced
  1303. ogg files can be safely chained.
  1304. @end table
  1305. @anchor{segment}
  1306. @section segment, stream_segment, ssegment
  1307. Basic stream segmenter.
  1308. This muxer outputs streams to a number of separate files of nearly
  1309. fixed duration. Output filename pattern can be set in a fashion
  1310. similar to @ref{image2}, or by using a @code{strftime} template if
  1311. the @option{strftime} option is enabled.
  1312. @code{stream_segment} is a variant of the muxer used to write to
  1313. streaming output formats, i.e. which do not require global headers,
  1314. and is recommended for outputting e.g. to MPEG transport stream segments.
  1315. @code{ssegment} is a shorter alias for @code{stream_segment}.
  1316. Every segment starts with a keyframe of the selected reference stream,
  1317. which is set through the @option{reference_stream} option.
  1318. Note that if you want accurate splitting for a video file, you need to
  1319. make the input key frames correspond to the exact splitting times
  1320. expected by the segmenter, or the segment muxer will start the new
  1321. segment with the key frame found next after the specified start
  1322. time.
  1323. The segment muxer works best with a single constant frame rate video.
  1324. Optionally it can generate a list of the created segments, by setting
  1325. the option @var{segment_list}. The list type is specified by the
  1326. @var{segment_list_type} option. The entry filenames in the segment
  1327. list are set by default to the basename of the corresponding segment
  1328. files.
  1329. See also the @ref{hls} muxer, which provides a more specific
  1330. implementation for HLS segmentation.
  1331. @subsection Options
  1332. The segment muxer supports the following options:
  1333. @table @option
  1334. @item increment_tc @var{1|0}
  1335. if set to @code{1}, increment timecode between each segment
  1336. If this is selected, the input need to have
  1337. a timecode in the first video stream. Default value is
  1338. @code{0}.
  1339. @item reference_stream @var{specifier}
  1340. Set the reference stream, as specified by the string @var{specifier}.
  1341. If @var{specifier} is set to @code{auto}, the reference is chosen
  1342. automatically. Otherwise it must be a stream specifier (see the ``Stream
  1343. specifiers'' chapter in the ffmpeg manual) which specifies the
  1344. reference stream. The default value is @code{auto}.
  1345. @item segment_format @var{format}
  1346. Override the inner container format, by default it is guessed by the filename
  1347. extension.
  1348. @item segment_format_options @var{options_list}
  1349. Set output format options using a :-separated list of key=value
  1350. parameters. Values containing the @code{:} special character must be
  1351. escaped.
  1352. @item segment_list @var{name}
  1353. Generate also a listfile named @var{name}. If not specified no
  1354. listfile is generated.
  1355. @item segment_list_flags @var{flags}
  1356. Set flags affecting the segment list generation.
  1357. It currently supports the following flags:
  1358. @table @samp
  1359. @item cache
  1360. Allow caching (only affects M3U8 list files).
  1361. @item live
  1362. Allow live-friendly file generation.
  1363. @end table
  1364. @item segment_list_size @var{size}
  1365. Update the list file so that it contains at most @var{size}
  1366. segments. If 0 the list file will contain all the segments. Default
  1367. value is 0.
  1368. @item segment_list_entry_prefix @var{prefix}
  1369. Prepend @var{prefix} to each entry. Useful to generate absolute paths.
  1370. By default no prefix is applied.
  1371. @item segment_list_type @var{type}
  1372. Select the listing format.
  1373. The following values are recognized:
  1374. @table @samp
  1375. @item flat
  1376. Generate a flat list for the created segments, one segment per line.
  1377. @item csv, ext
  1378. Generate a list for the created segments, one segment per line,
  1379. each line matching the format (comma-separated values):
  1380. @example
  1381. @var{segment_filename},@var{segment_start_time},@var{segment_end_time}
  1382. @end example
  1383. @var{segment_filename} is the name of the output file generated by the
  1384. muxer according to the provided pattern. CSV escaping (according to
  1385. RFC4180) is applied if required.
  1386. @var{segment_start_time} and @var{segment_end_time} specify
  1387. the segment start and end time expressed in seconds.
  1388. A list file with the suffix @code{".csv"} or @code{".ext"} will
  1389. auto-select this format.
  1390. @samp{ext} is deprecated in favor or @samp{csv}.
  1391. @item ffconcat
  1392. Generate an ffconcat file for the created segments. The resulting file
  1393. can be read using the FFmpeg @ref{concat} demuxer.
  1394. A list file with the suffix @code{".ffcat"} or @code{".ffconcat"} will
  1395. auto-select this format.
  1396. @item m3u8
  1397. Generate an extended M3U8 file, version 3, compliant with
  1398. @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}.
  1399. A list file with the suffix @code{".m3u8"} will auto-select this format.
  1400. @end table
  1401. If not specified the type is guessed from the list file name suffix.
  1402. @item segment_time @var{time}
  1403. Set segment duration to @var{time}, the value must be a duration
  1404. specification. Default value is "2". See also the
  1405. @option{segment_times} option.
  1406. Note that splitting may not be accurate, unless you force the
  1407. reference stream key-frames at the given time. See the introductory
  1408. notice and the examples below.
  1409. @item segment_atclocktime @var{1|0}
  1410. If set to "1" split at regular clock time intervals starting from 00:00
  1411. o'clock. The @var{time} value specified in @option{segment_time} is
  1412. used for setting the length of the splitting interval.
  1413. For example with @option{segment_time} set to "900" this makes it possible
  1414. to create files at 12:00 o'clock, 12:15, 12:30, etc.
  1415. Default value is "0".
  1416. @item segment_clocktime_offset @var{duration}
  1417. Delay the segment splitting times with the specified duration when using
  1418. @option{segment_atclocktime}.
  1419. For example with @option{segment_time} set to "900" and
  1420. @option{segment_clocktime_offset} set to "300" this makes it possible to
  1421. create files at 12:05, 12:20, 12:35, etc.
  1422. Default value is "0".
  1423. @item segment_clocktime_wrap_duration @var{duration}
  1424. Force the segmenter to only start a new segment if a packet reaches the muxer
  1425. within the specified duration after the segmenting clock time. This way you
  1426. can make the segmenter more resilient to backward local time jumps, such as
  1427. leap seconds or transition to standard time from daylight savings time.
  1428. Default is the maximum possible duration which means starting a new segment
  1429. regardless of the elapsed time since the last clock time.
  1430. @item segment_time_delta @var{delta}
  1431. Specify the accuracy time when selecting the start time for a
  1432. segment, expressed as a duration specification. Default value is "0".
  1433. When delta is specified a key-frame will start a new segment if its
  1434. PTS satisfies the relation:
  1435. @example
  1436. PTS >= start_time - time_delta
  1437. @end example
  1438. This option is useful when splitting video content, which is always
  1439. split at GOP boundaries, in case a key frame is found just before the
  1440. specified split time.
  1441. In particular may be used in combination with the @file{ffmpeg} option
  1442. @var{force_key_frames}. The key frame times specified by
  1443. @var{force_key_frames} may not be set accurately because of rounding
  1444. issues, with the consequence that a key frame time may result set just
  1445. before the specified time. For constant frame rate videos a value of
  1446. 1/(2*@var{frame_rate}) should address the worst case mismatch between
  1447. the specified time and the time set by @var{force_key_frames}.
  1448. @item segment_times @var{times}
  1449. Specify a list of split points. @var{times} contains a list of comma
  1450. separated duration specifications, in increasing order. See also
  1451. the @option{segment_time} option.
  1452. @item segment_frames @var{frames}
  1453. Specify a list of split video frame numbers. @var{frames} contains a
  1454. list of comma separated integer numbers, in increasing order.
  1455. This option specifies to start a new segment whenever a reference
  1456. stream key frame is found and the sequential number (starting from 0)
  1457. of the frame is greater or equal to the next value in the list.
  1458. @item segment_wrap @var{limit}
  1459. Wrap around segment index once it reaches @var{limit}.
  1460. @item segment_start_number @var{number}
  1461. Set the sequence number of the first segment. Defaults to @code{0}.
  1462. @item strftime @var{1|0}
  1463. Use the @code{strftime} function to define the name of the new
  1464. segments to write. If this is selected, the output segment name must
  1465. contain a @code{strftime} function template. Default value is
  1466. @code{0}.
  1467. @item break_non_keyframes @var{1|0}
  1468. If enabled, allow segments to start on frames other than keyframes. This
  1469. improves behavior on some players when the time between keyframes is
  1470. inconsistent, but may make things worse on others, and can cause some oddities
  1471. during seeking. Defaults to @code{0}.
  1472. @item reset_timestamps @var{1|0}
  1473. Reset timestamps at the beginning of each segment, so that each segment
  1474. will start with near-zero timestamps. It is meant to ease the playback
  1475. of the generated segments. May not work with some combinations of
  1476. muxers/codecs. It is set to @code{0} by default.
  1477. @item initial_offset @var{offset}
  1478. Specify timestamp offset to apply to the output packet timestamps. The
  1479. argument must be a time duration specification, and defaults to 0.
  1480. @item write_empty_segments @var{1|0}
  1481. If enabled, write an empty segment if there are no packets during the period a
  1482. segment would usually span. Otherwise, the segment will be filled with the next
  1483. packet written. Defaults to @code{0}.
  1484. @end table
  1485. Make sure to require a closed GOP when encoding and to set the GOP
  1486. size to fit your segment time constraint.
  1487. @subsection Examples
  1488. @itemize
  1489. @item
  1490. Remux the content of file @file{in.mkv} to a list of segments
  1491. @file{out-000.nut}, @file{out-001.nut}, etc., and write the list of
  1492. generated segments to @file{out.list}:
  1493. @example
  1494. ffmpeg -i in.mkv -codec hevc -flags +cgop -g 60 -map 0 -f segment -segment_list out.list out%03d.nut
  1495. @end example
  1496. @item
  1497. Segment input and set output format options for the output segments:
  1498. @example
  1499. ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4
  1500. @end example
  1501. @item
  1502. Segment the input file according to the split points specified by the
  1503. @var{segment_times} option:
  1504. @example
  1505. 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
  1506. @end example
  1507. @item
  1508. Use the @command{ffmpeg} @option{force_key_frames}
  1509. option to force key frames in the input at the specified location, together
  1510. with the segment option @option{segment_time_delta} to account for
  1511. possible roundings operated when setting key frame times.
  1512. @example
  1513. ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
  1514. -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut
  1515. @end example
  1516. In order to force key frames on the input file, transcoding is
  1517. required.
  1518. @item
  1519. Segment the input file by splitting the input file according to the
  1520. frame numbers sequence specified with the @option{segment_frames} option:
  1521. @example
  1522. ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut
  1523. @end example
  1524. @item
  1525. Convert the @file{in.mkv} to TS segments using the @code{libx264}
  1526. and @code{aac} encoders:
  1527. @example
  1528. ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a aac -f ssegment -segment_list out.list out%03d.ts
  1529. @end example
  1530. @item
  1531. Segment the input file, and create an M3U8 live playlist (can be used
  1532. as live HLS source):
  1533. @example
  1534. ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
  1535. -segment_list_flags +live -segment_time 10 out%03d.mkv
  1536. @end example
  1537. @end itemize
  1538. @section smoothstreaming
  1539. Smooth Streaming muxer generates a set of files (Manifest, chunks) suitable for serving with conventional web server.
  1540. @table @option
  1541. @item window_size
  1542. Specify the number of fragments kept in the manifest. Default 0 (keep all).
  1543. @item extra_window_size
  1544. Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.
  1545. @item lookahead_count
  1546. Specify the number of lookahead fragments. Default 2.
  1547. @item min_frag_duration
  1548. Specify the minimum fragment duration (in microseconds). Default 5000000.
  1549. @item remove_at_exit
  1550. Specify whether to remove all fragments when finished. Default 0 (do not remove).
  1551. @end table
  1552. @anchor{fifo}
  1553. @section fifo
  1554. The fifo pseudo-muxer allows the separation of encoding and muxing by using
  1555. first-in-first-out queue and running the actual muxer in a separate thread. This
  1556. is especially useful in combination with the @ref{tee} muxer and can be used to
  1557. send data to several destinations with different reliability/writing speed/latency.
  1558. API users should be aware that callback functions (interrupt_callback,
  1559. io_open and io_close) used within its AVFormatContext must be thread-safe.
  1560. The behavior of the fifo muxer if the queue fills up or if the output fails is
  1561. selectable,
  1562. @itemize @bullet
  1563. @item
  1564. output can be transparently restarted with configurable delay between retries
  1565. based on real time or time of the processed stream.
  1566. @item
  1567. encoding can be blocked during temporary failure, or continue transparently
  1568. dropping packets in case fifo queue fills up.
  1569. @end itemize
  1570. @table @option
  1571. @item fifo_format
  1572. Specify the format name. Useful if it cannot be guessed from the
  1573. output name suffix.
  1574. @item queue_size
  1575. Specify size of the queue (number of packets). Default value is 60.
  1576. @item format_opts
  1577. Specify format options for the underlying muxer. Muxer options can be specified
  1578. as a list of @var{key}=@var{value} pairs separated by ':'.
  1579. @item drop_pkts_on_overflow @var{bool}
  1580. If set to 1 (true), in case the fifo queue fills up, packets will be dropped
  1581. rather than blocking the encoder. This makes it possible to continue streaming without
  1582. delaying the input, at the cost of omitting part of the stream. By default
  1583. this option is set to 0 (false), so in such cases the encoder will be blocked
  1584. until the muxer processes some of the packets and none of them is lost.
  1585. @item attempt_recovery @var{bool}
  1586. If failure occurs, attempt to recover the output. This is especially useful
  1587. when used with network output, since it makes it possible to restart streaming transparently.
  1588. By default this option is set to 0 (false).
  1589. @item max_recovery_attempts
  1590. Sets maximum number of successive unsuccessful recovery attempts after which
  1591. the output fails permanently. By default this option is set to 0 (unlimited).
  1592. @item recovery_wait_time @var{duration}
  1593. Waiting time before the next recovery attempt after previous unsuccessful
  1594. recovery attempt. Default value is 5 seconds.
  1595. @item recovery_wait_streamtime @var{bool}
  1596. If set to 0 (false), the real time is used when waiting for the recovery
  1597. attempt (i.e. the recovery will be attempted after at least
  1598. recovery_wait_time seconds).
  1599. If set to 1 (true), the time of the processed stream is taken into account
  1600. instead (i.e. the recovery will be attempted after at least @var{recovery_wait_time}
  1601. seconds of the stream is omitted).
  1602. By default, this option is set to 0 (false).
  1603. @item recover_any_error @var{bool}
  1604. If set to 1 (true), recovery will be attempted regardless of type of the error
  1605. causing the failure. By default this option is set to 0 (false) and in case of
  1606. certain (usually permanent) errors the recovery is not attempted even when
  1607. @var{attempt_recovery} is set to 1.
  1608. @item restart_with_keyframe @var{bool}
  1609. Specify whether to wait for the keyframe after recovering from
  1610. queue overflow or failure. This option is set to 0 (false) by default.
  1611. @end table
  1612. @subsection Examples
  1613. @itemize
  1614. @item
  1615. Stream something to rtmp server, continue processing the stream at real-time
  1616. rate even in case of temporary failure (network outage) and attempt to recover
  1617. streaming every second indefinitely.
  1618. @example
  1619. ffmpeg -re -i ... -c:v libx264 -c:a aac -f fifo -fifo_format flv -map 0:v -map 0:a
  1620. -drop_pkts_on_overflow 1 -attempt_recovery 1 -recovery_wait_time 1 rtmp://example.com/live/stream_name
  1621. @end example
  1622. @end itemize
  1623. @anchor{tee}
  1624. @section tee
  1625. The tee muxer can be used to write the same data to several outputs, such as files or streams.
  1626. It can be used, for example, to stream a video over a network and save it to disk at the same time.
  1627. It is different from specifying several outputs to the @command{ffmpeg}
  1628. command-line tool. With the tee muxer, the audio and video data will be encoded only once.
  1629. With conventional multiple outputs, multiple encoding operations in parallel are initiated,
  1630. which can be a very expensive process. The tee muxer is not useful when using the libavformat API
  1631. directly because it is then possible to feed the same packets to several muxers directly.
  1632. Since the tee muxer does not represent any particular output format, ffmpeg cannot auto-select
  1633. output streams. So all streams intended for output must be specified using @code{-map}. See
  1634. the examples below.
  1635. Some encoders may need different options depending on the output format;
  1636. the auto-detection of this can not work with the tee muxer, so they need to be explicitly specified.
  1637. The main example is the @option{global_header} flag.
  1638. The slave outputs are specified in the file name given to the muxer,
  1639. separated by '|'. If any of the slave name contains the '|' separator,
  1640. leading or trailing spaces or any special character, those must be
  1641. escaped (see @ref{quoting_and_escaping,,the "Quoting and escaping"
  1642. section in the ffmpeg-utils(1) manual,ffmpeg-utils}).
  1643. @subsection Options
  1644. @table @option
  1645. @item use_fifo @var{bool}
  1646. If set to 1, slave outputs will be processed in separate threads using the @ref{fifo}
  1647. muxer. This allows to compensate for different speed/latency/reliability of
  1648. outputs and setup transparent recovery. By default this feature is turned off.
  1649. @item fifo_options
  1650. Options to pass to fifo pseudo-muxer instances. See @ref{fifo}.
  1651. @end table
  1652. Muxer options can be specified for each slave by prepending them as a list of
  1653. @var{key}=@var{value} pairs separated by ':', between square brackets. If
  1654. the options values contain a special character or the ':' separator, they
  1655. must be escaped; note that this is a second level escaping.
  1656. The following special options are also recognized:
  1657. @table @option
  1658. @item f
  1659. Specify the format name. Required if it cannot be guessed from the
  1660. output URL.
  1661. @item bsfs[/@var{spec}]
  1662. Specify a list of bitstream filters to apply to the specified
  1663. output.
  1664. It is possible to specify to which streams a given bitstream filter
  1665. applies, by appending a stream specifier to the option separated by
  1666. @code{/}. @var{spec} must be a stream specifier (see @ref{Format
  1667. stream specifiers}).
  1668. If the stream specifier is not specified, the bitstream filters will be
  1669. applied to all streams in the output. This will cause that output operation
  1670. to fail if the output contains streams to which the bitstream filter cannot
  1671. be applied e.g. @code{h264_mp4toannexb} being applied to an output containing an audio stream.
  1672. Options for a bitstream filter must be specified in the form of @code{opt=value}.
  1673. Several bitstream filters can be specified, separated by ",".
  1674. @item use_fifo @var{bool}
  1675. This allows to override tee muxer use_fifo option for individual slave muxer.
  1676. @item fifo_options
  1677. This allows to override tee muxer fifo_options for individual slave muxer.
  1678. See @ref{fifo}.
  1679. @item select
  1680. Select the streams that should be mapped to the slave output,
  1681. specified by a stream specifier. If not specified, this defaults to
  1682. all the mapped streams. This will cause that output operation to fail
  1683. if the output format does not accept all mapped streams.
  1684. You may use multiple stream specifiers separated by commas (@code{,}) e.g.: @code{a:0,v}
  1685. @item onfail
  1686. Specify behaviour on output failure. This can be set to either @code{abort} (which is
  1687. default) or @code{ignore}. @code{abort} will cause whole process to fail in case of failure
  1688. on this slave output. @code{ignore} will ignore failure on this output, so other outputs
  1689. will continue without being affected.
  1690. @end table
  1691. @subsection Examples
  1692. @itemize
  1693. @item
  1694. Encode something and both archive it in a WebM file and stream it
  1695. as MPEG-TS over UDP:
  1696. @example
  1697. ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
  1698. "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
  1699. @end example
  1700. @item
  1701. As above, but continue streaming even if output to local file fails
  1702. (for example local drive fills up):
  1703. @example
  1704. ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
  1705. "[onfail=ignore]archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
  1706. @end example
  1707. @item
  1708. Use @command{ffmpeg} to encode the input, and send the output
  1709. to three different destinations. The @code{dump_extra} bitstream
  1710. filter is used to add extradata information to all the output video
  1711. keyframes packets, as requested by the MPEG-TS format. The select
  1712. option is applied to @file{out.aac} in order to make it contain only
  1713. audio packets.
  1714. @example
  1715. ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
  1716. -f tee "[bsfs/v=dump_extra=freq=keyframe]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"
  1717. @end example
  1718. @item
  1719. As above, but select only stream @code{a:1} for the audio output. Note
  1720. that a second level escaping must be performed, as ":" is a special
  1721. character used to separate options.
  1722. @example
  1723. ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac
  1724. -f tee "[bsfs/v=dump_extra=freq=keyframe]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"
  1725. @end example
  1726. @end itemize
  1727. @section webm_dash_manifest
  1728. WebM DASH Manifest muxer.
  1729. This muxer implements the WebM DASH Manifest specification to generate the DASH
  1730. manifest XML. It also supports manifest generation for DASH live streams.
  1731. For more information see:
  1732. @itemize @bullet
  1733. @item
  1734. WebM DASH Specification: @url{https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification}
  1735. @item
  1736. ISO DASH Specification: @url{http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip}
  1737. @end itemize
  1738. @subsection Options
  1739. This muxer supports the following options:
  1740. @table @option
  1741. @item adaptation_sets
  1742. This option has the following syntax: "id=x,streams=a,b,c id=y,streams=d,e" where x and y are the
  1743. unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding
  1744. audio and video streams. Any number of adaptation sets can be added using this option.
  1745. @item live
  1746. Set this to 1 to create a live stream DASH Manifest. Default: 0.
  1747. @item chunk_start_index
  1748. Start index of the first chunk. This will go in the @samp{startNumber} attribute
  1749. of the @samp{SegmentTemplate} element in the manifest. Default: 0.
  1750. @item chunk_duration_ms
  1751. Duration of each chunk in milliseconds. This will go in the @samp{duration}
  1752. attribute of the @samp{SegmentTemplate} element in the manifest. Default: 1000.
  1753. @item utc_timing_url
  1754. URL of the page that will return the UTC timestamp in ISO format. This will go
  1755. in the @samp{value} attribute of the @samp{UTCTiming} element in the manifest.
  1756. Default: None.
  1757. @item time_shift_buffer_depth
  1758. Smallest time (in seconds) shifting buffer for which any Representation is
  1759. guaranteed to be available. This will go in the @samp{timeShiftBufferDepth}
  1760. attribute of the @samp{MPD} element. Default: 60.
  1761. @item minimum_update_period
  1762. Minimum update period (in seconds) of the manifest. This will go in the
  1763. @samp{minimumUpdatePeriod} attribute of the @samp{MPD} element. Default: 0.
  1764. @end table
  1765. @subsection Example
  1766. @example
  1767. ffmpeg -f webm_dash_manifest -i video1.webm \
  1768. -f webm_dash_manifest -i video2.webm \
  1769. -f webm_dash_manifest -i audio1.webm \
  1770. -f webm_dash_manifest -i audio2.webm \
  1771. -map 0 -map 1 -map 2 -map 3 \
  1772. -c copy \
  1773. -f webm_dash_manifest \
  1774. -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \
  1775. manifest.xml
  1776. @end example
  1777. @section webm_chunk
  1778. WebM Live Chunk Muxer.
  1779. This muxer writes out WebM headers and chunks as separate files which can be
  1780. consumed by clients that support WebM Live streams via DASH.
  1781. @subsection Options
  1782. This muxer supports the following options:
  1783. @table @option
  1784. @item chunk_start_index
  1785. Index of the first chunk (defaults to 0).
  1786. @item header
  1787. Filename of the header where the initialization data will be written.
  1788. @item audio_chunk_duration
  1789. Duration of each audio chunk in milliseconds (defaults to 5000).
  1790. @end table
  1791. @subsection Example
  1792. @example
  1793. ffmpeg -f v4l2 -i /dev/video0 \
  1794. -f alsa -i hw:0 \
  1795. -map 0:0 \
  1796. -c:v libvpx-vp9 \
  1797. -s 640x360 -keyint_min 30 -g 30 \
  1798. -f webm_chunk \
  1799. -header webm_live_video_360.hdr \
  1800. -chunk_start_index 1 \
  1801. webm_live_video_360_%d.chk \
  1802. -map 1:0 \
  1803. -c:a libvorbis \
  1804. -b:a 128k \
  1805. -f webm_chunk \
  1806. -header webm_live_audio_128.hdr \
  1807. -chunk_start_index 1 \
  1808. -audio_chunk_duration 1000 \
  1809. webm_live_audio_128_%d.chk
  1810. @end example
  1811. @c man end MUXERS