You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

1444 lines
55KB

  1. \input texinfo @c -*- texinfo -*-
  2. @settitle ffmpeg Documentation
  3. @titlepage
  4. @center @titlefont{ffmpeg Documentation}
  5. @end titlepage
  6. @top
  7. @contents
  8. @chapter Synopsis
  9. ffmpeg [@var{global_options}] @{[@var{input_file_options}] -i @file{input_file}@} ... @{[@var{output_file_options}] @file{output_file}@} ...
  10. @chapter Description
  11. @c man begin DESCRIPTION
  12. @command{ffmpeg} is a very fast video and audio converter that can also grab from
  13. a live audio/video source. It can also convert between arbitrary sample
  14. rates and resize video on the fly with a high quality polyphase filter.
  15. @command{ffmpeg} reads from an arbitrary number of input "files" (which can be regular
  16. files, pipes, network streams, grabbing devices, etc.), specified by the
  17. @code{-i} option, and writes to an arbitrary number of output "files", which are
  18. specified by a plain output filename. Anything found on the command line which
  19. cannot be interpreted as an option is considered to be an output filename.
  20. Each input or output file can, in principle, contain any number of streams of
  21. different types (video/audio/subtitle/attachment/data). The allowed number and/or
  22. types of streams may be limited by the container format. Selecting which
  23. streams from which inputs will go into which output is either done automatically
  24. or with the @code{-map} option (see the Stream selection chapter).
  25. To refer to input files in options, you must use their indices (0-based). E.g.
  26. the first input file is @code{0}, the second is @code{1}, etc. Similarly, streams
  27. within a file are referred to by their indices. E.g. @code{2:3} refers to the
  28. fourth stream in the third input file. Also see the Stream specifiers chapter.
  29. As a general rule, options are applied to the next specified
  30. file. Therefore, order is important, and you can have the same
  31. option on the command line multiple times. Each occurrence is
  32. then applied to the next input or output file.
  33. Exceptions from this rule are the global options (e.g. verbosity level),
  34. which should be specified first.
  35. Do not mix input and output files -- first specify all input files, then all
  36. output files. Also do not mix options which belong to different files. All
  37. options apply ONLY to the next input or output file and are reset between files.
  38. @itemize
  39. @item
  40. To set the video bitrate of the output file to 64 kbit/s:
  41. @example
  42. ffmpeg -i input.avi -b:v 64k -bufsize 64k output.avi
  43. @end example
  44. @item
  45. To force the frame rate of the output file to 24 fps:
  46. @example
  47. ffmpeg -i input.avi -r 24 output.avi
  48. @end example
  49. @item
  50. To force the frame rate of the input file (valid for raw formats only)
  51. to 1 fps and the frame rate of the output file to 24 fps:
  52. @example
  53. ffmpeg -r 1 -i input.m2v -r 24 output.avi
  54. @end example
  55. @end itemize
  56. The format option may be needed for raw input files.
  57. @c man end DESCRIPTION
  58. @chapter Detailed description
  59. @c man begin DETAILED DESCRIPTION
  60. The transcoding process in @command{ffmpeg} for each output can be described by
  61. the following diagram:
  62. @example
  63. _______ ______________ _________ ______________ ________
  64. | | | | | | | | | |
  65. | input | demuxer | encoded data | decoder | decoded | encoder | encoded data | muxer | output |
  66. | file | ---------> | packets | ---------> | frames | ---------> | packets | -------> | file |
  67. |_______| |______________| |_________| |______________| |________|
  68. @end example
  69. @command{ffmpeg} calls the libavformat library (containing demuxers) to read
  70. input files and get packets containing encoded data from them. When there are
  71. multiple input files, @command{ffmpeg} tries to keep them synchronized by
  72. tracking lowest timestamp on any active input stream.
  73. Encoded packets are then passed to the decoder (unless streamcopy is selected
  74. for the stream, see further for a description). The decoder produces
  75. uncompressed frames (raw video/PCM audio/...) which can be processed further by
  76. filtering (see next section). After filtering, the frames are passed to the
  77. encoder, which encodes them and outputs encoded packets. Finally those are
  78. passed to the muxer, which writes the encoded packets to the output file.
  79. @section Filtering
  80. Before encoding, @command{ffmpeg} can process raw audio and video frames using
  81. filters from the libavfilter library. Several chained filters form a filter
  82. graph. @command{ffmpeg} distinguishes between two types of filtergraphs:
  83. simple and complex.
  84. @subsection Simple filtergraphs
  85. Simple filtergraphs are those that have exactly one input and output, both of
  86. the same type. In the above diagram they can be represented by simply inserting
  87. an additional step between decoding and encoding:
  88. @example
  89. _________ __________ ______________
  90. | | | | | |
  91. | decoded | simple filtergraph | filtered | encoder | encoded data |
  92. | frames | -------------------> | frames | ---------> | packets |
  93. |_________| |__________| |______________|
  94. @end example
  95. Simple filtergraphs are configured with the per-stream @option{-filter} option
  96. (with @option{-vf} and @option{-af} aliases for video and audio respectively).
  97. A simple filtergraph for video can look for example like this:
  98. @example
  99. _______ _____________ _______ _____ ________
  100. | | | | | | | | | |
  101. | input | ---> | deinterlace | ---> | scale | ---> | fps | ---> | output |
  102. |_______| |_____________| |_______| |_____| |________|
  103. @end example
  104. Note that some filters change frame properties but not frame contents. E.g. the
  105. @code{fps} filter in the example above changes number of frames, but does not
  106. touch the frame contents. Another example is the @code{setpts} filter, which
  107. only sets timestamps and otherwise passes the frames unchanged.
  108. @subsection Complex filtergraphs
  109. Complex filtergraphs are those which cannot be described as simply a linear
  110. processing chain applied to one stream. This is the case, for example, when the graph has
  111. more than one input and/or output, or when output stream type is different from
  112. input. They can be represented with the following diagram:
  113. @example
  114. _________
  115. | |
  116. | input 0 |\ __________
  117. |_________| \ | |
  118. \ _________ /| output 0 |
  119. \ | | / |__________|
  120. _________ \| complex | /
  121. | | | |/
  122. | input 1 |---->| filter |\
  123. |_________| | | \ __________
  124. /| graph | \ | |
  125. / | | \| output 1 |
  126. _________ / |_________| |__________|
  127. | | /
  128. | input 2 |/
  129. |_________|
  130. @end example
  131. Complex filtergraphs are configured with the @option{-filter_complex} option.
  132. Note that this option is global, since a complex filtergraph, by its nature,
  133. cannot be unambiguously associated with a single stream or file.
  134. The @option{-lavfi} option is equivalent to @option{-filter_complex}.
  135. A trivial example of a complex filtergraph is the @code{overlay} filter, which
  136. has two video inputs and one video output, containing one video overlaid on top
  137. of the other. Its audio counterpart is the @code{amix} filter.
  138. @section Stream copy
  139. Stream copy is a mode selected by supplying the @code{copy} parameter to the
  140. @option{-codec} option. It makes @command{ffmpeg} omit the decoding and encoding
  141. step for the specified stream, so it does only demuxing and muxing. It is useful
  142. for changing the container format or modifying container-level metadata. The
  143. diagram above will, in this case, simplify to this:
  144. @example
  145. _______ ______________ ________
  146. | | | | | |
  147. | input | demuxer | encoded data | muxer | output |
  148. | file | ---------> | packets | -------> | file |
  149. |_______| |______________| |________|
  150. @end example
  151. Since there is no decoding or encoding, it is very fast and there is no quality
  152. loss. However, it might not work in some cases because of many factors. Applying
  153. filters is obviously also impossible, since filters work on uncompressed data.
  154. @c man end DETAILED DESCRIPTION
  155. @chapter Stream selection
  156. @c man begin STREAM SELECTION
  157. By default, @command{ffmpeg} includes only one stream of each type (video, audio, subtitle)
  158. present in the input files and adds them to each output file. It picks the
  159. "best" of each based upon the following criteria: for video, it is the stream
  160. with the highest resolution, for audio, it is the stream with the most channels, for
  161. subtitles, it is the first subtitle stream. In the case where several streams of
  162. the same type rate equally, the stream with the lowest index is chosen.
  163. You can disable some of those defaults by using the @code{-vn/-an/-sn} options. For
  164. full manual control, use the @code{-map} option, which disables the defaults just
  165. described.
  166. @c man end STREAM SELECTION
  167. @chapter Options
  168. @c man begin OPTIONS
  169. @include avtools-common-opts.texi
  170. @section Main options
  171. @table @option
  172. @item -f @var{fmt} (@emph{input/output})
  173. Force input or output file format. The format is normally auto detected for input
  174. files and guessed from the file extension for output files, so this option is not
  175. needed in most cases.
  176. @item -i @var{filename} (@emph{input})
  177. input file name
  178. @item -y (@emph{global})
  179. Overwrite output files without asking.
  180. @item -n (@emph{global})
  181. Do not overwrite output files, and exit immediately if a specified
  182. output file already exists.
  183. @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
  184. @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
  185. Select an encoder (when used before an output file) or a decoder (when used
  186. before an input file) for one or more streams. @var{codec} is the name of a
  187. decoder/encoder or a special value @code{copy} (output only) to indicate that
  188. the stream is not to be re-encoded.
  189. For example
  190. @example
  191. ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
  192. @end example
  193. encodes all video streams with libx264 and copies all audio streams.
  194. For each stream, the last matching @code{c} option is applied, so
  195. @example
  196. ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
  197. @end example
  198. will copy all the streams except the second video, which will be encoded with
  199. libx264, and the 138th audio, which will be encoded with libvorbis.
  200. @item -t @var{duration} (@emph{output})
  201. Stop writing the output after its duration reaches @var{duration}.
  202. @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
  203. -to and -t are mutually exclusive and -t has priority.
  204. @item -to @var{position} (@emph{output})
  205. Stop writing the output at @var{position}.
  206. @var{position} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
  207. -to and -t are mutually exclusive and -t has priority.
  208. @item -fs @var{limit_size} (@emph{output})
  209. Set the file size limit, expressed in bytes.
  210. @item -ss @var{position} (@emph{input/output})
  211. When used as an input option (before @code{-i}), seeks in this input file to
  212. @var{position}. When used as an output option (before an output filename),
  213. decodes but discards input until the timestamps reach @var{position}. This is
  214. slower, but more accurate.
  215. @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
  216. @item -itsoffset @var{offset} (@emph{input})
  217. Set the input time offset in seconds.
  218. @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
  219. The offset is added to the timestamps of the input files.
  220. Specifying a positive offset means that the corresponding
  221. streams are delayed by @var{offset} seconds.
  222. @item -timestamp @var{time} (@emph{output})
  223. Set the recording timestamp in the container.
  224. The syntax for @var{time} is:
  225. @example
  226. now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...])|(HHMMSS[.m...]))[Z|z])
  227. @end example
  228. If the value is "now" it takes the current time.
  229. Time is local time unless 'Z' or 'z' is appended, in which case it is
  230. interpreted as UTC.
  231. If the year-month-day part is not specified it takes the current
  232. year-month-day.
  233. @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
  234. Set a metadata key/value pair.
  235. An optional @var{metadata_specifier} may be given to set metadata
  236. on streams or chapters. See @code{-map_metadata} documentation for
  237. details.
  238. This option overrides metadata set with @code{-map_metadata}. It is
  239. also possible to delete metadata by using an empty value.
  240. For example, for setting the title in the output file:
  241. @example
  242. ffmpeg -i in.avi -metadata title="my title" out.flv
  243. @end example
  244. To set the language of the first audio stream:
  245. @example
  246. ffmpeg -i INPUT -metadata:s:a:1 language=eng OUTPUT
  247. @end example
  248. @item -target @var{type} (@emph{output})
  249. Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
  250. @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
  251. @code{film-} to use the corresponding standard. All the format options
  252. (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
  253. @example
  254. ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
  255. @end example
  256. Nevertheless you can specify additional options as long as you know
  257. they do not conflict with the standard, as in:
  258. @example
  259. ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
  260. @end example
  261. @item -dframes @var{number} (@emph{output})
  262. Set the number of data frames to record. This is an alias for @code{-frames:d}.
  263. @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
  264. Stop writing to the stream after @var{framecount} frames.
  265. @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
  266. @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
  267. Use fixed quality scale (VBR). The meaning of @var{q} is
  268. codec-dependent.
  269. @anchor{filter_option}
  270. @item -filter[:@var{stream_specifier}] @var{filtergraph} (@emph{output,per-stream})
  271. Create the filtergraph specified by @var{filtergraph} and use it to
  272. filter the stream.
  273. @var{filtergraph} is a description of the filtergraph to apply to
  274. the stream, and must have a single input and a single output of the
  275. same type of the stream. In the filtergraph, the input is associated
  276. to the label @code{in}, and the output to the label @code{out}. See
  277. the ffmpeg-filters manual for more information about the filtergraph
  278. syntax.
  279. See the @ref{filter_complex_option,,-filter_complex option} if you
  280. want to create filtergraphs with multiple inputs and/or outputs.
  281. @item -filter_script[:@var{stream_specifier}] @var{filename} (@emph{output,per-stream})
  282. This option is similar to @option{-filter}, the only difference is that its
  283. argument is the name of the file from which a filtergraph description is to be
  284. read.
  285. @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
  286. Specify the preset for matching stream(s).
  287. @item -stats (@emph{global})
  288. Print encoding progress/statistics. It is on by default, to explicitly
  289. disable it you need to specify @code{-nostats}.
  290. @item -progress @var{url} (@emph{global})
  291. Send program-friendly progress information to @var{url}.
  292. Progress information is written approximately every second and at the end of
  293. the encoding process. It is made of "@var{key}=@var{value}" lines. @var{key}
  294. consists of only alphanumeric characters. The last key of a sequence of
  295. progress information is always "progress".
  296. @item -stdin
  297. Enable interaction on standard input. On by default unless standard input is
  298. used as an input. To explicitly disable interaction you need to specify
  299. @code{-nostdin}.
  300. Disabling interaction on standard input is useful, for example, if
  301. ffmpeg is in the background process group. Roughly the same result can
  302. be achieved with @code{ffmpeg ... < /dev/null} but it requires a
  303. shell.
  304. @item -debug_ts (@emph{global})
  305. Print timestamp information. It is off by default. This option is
  306. mostly useful for testing and debugging purposes, and the output
  307. format may change from one version to another, so it should not be
  308. employed by portable scripts.
  309. See also the option @code{-fdebug ts}.
  310. @item -attach @var{filename} (@emph{output})
  311. Add an attachment to the output file. This is supported by a few formats
  312. like Matroska for e.g. fonts used in rendering subtitles. Attachments
  313. are implemented as a specific type of stream, so this option will add
  314. a new stream to the file. It is then possible to use per-stream options
  315. on this stream in the usual way. Attachment streams created with this
  316. option will be created after all the other streams (i.e. those created
  317. with @code{-map} or automatic mappings).
  318. Note that for Matroska you also have to set the mimetype metadata tag:
  319. @example
  320. ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
  321. @end example
  322. (assuming that the attachment stream will be third in the output file).
  323. @item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
  324. Extract the matching attachment stream into a file named @var{filename}. If
  325. @var{filename} is empty, then the value of the @code{filename} metadata tag
  326. will be used.
  327. E.g. to extract the first attachment to a file named 'out.ttf':
  328. @example
  329. ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
  330. @end example
  331. To extract all attachments to files determined by the @code{filename} tag:
  332. @example
  333. ffmpeg -dump_attachment:t "" -i INPUT
  334. @end example
  335. Technical note -- attachments are implemented as codec extradata, so this
  336. option can actually be used to extract extradata from any stream, not just
  337. attachments.
  338. @end table
  339. @section Video Options
  340. @table @option
  341. @item -vframes @var{number} (@emph{output})
  342. Set the number of video frames to record. This is an alias for @code{-frames:v}.
  343. @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
  344. Set frame rate (Hz value, fraction or abbreviation).
  345. As an input option, ignore any timestamps stored in the file and instead
  346. generate timestamps assuming constant frame rate @var{fps}.
  347. As an output option, duplicate or drop input frames to achieve constant output
  348. frame rate @var{fps}.
  349. @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
  350. Set frame size.
  351. As an input option, this is a shortcut for the @option{video_size} private
  352. option, recognized by some demuxers for which the frame size is either not
  353. stored in the file or is configurable -- e.g. raw video or video grabbers.
  354. As an output option, this inserts the @code{scale} video filter to the
  355. @emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
  356. directly to insert it at the beginning or some other place.
  357. The format is @samp{wxh} (default - same as source).
  358. @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
  359. Set the video display aspect ratio specified by @var{aspect}.
  360. @var{aspect} can be a floating point number string, or a string of the
  361. form @var{num}:@var{den}, where @var{num} and @var{den} are the
  362. numerator and denominator of the aspect ratio. For example "4:3",
  363. "16:9", "1.3333", and "1.7777" are valid argument values.
  364. If used together with @option{-vcodec copy}, it will affect the aspect ratio
  365. stored at container level, but not the aspect ratio stored in encoded
  366. frames, if it exists.
  367. @item -vn (@emph{output})
  368. Disable video recording.
  369. @item -vcodec @var{codec} (@emph{output})
  370. Set the video codec. This is an alias for @code{-codec:v}.
  371. @item -pass[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
  372. Select the pass number (1 or 2). It is used to do two-pass
  373. video encoding. The statistics of the video are recorded in the first
  374. pass into a log file (see also the option -passlogfile),
  375. and in the second pass that log file is used to generate the video
  376. at the exact requested bitrate.
  377. On pass 1, you may just deactivate audio and set output to null,
  378. examples for Windows and Unix:
  379. @example
  380. ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
  381. ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
  382. @end example
  383. @item -passlogfile[:@var{stream_specifier}] @var{prefix} (@emph{output,per-stream})
  384. Set two-pass log file name prefix to @var{prefix}, the default file name
  385. prefix is ``ffmpeg2pass''. The complete file name will be
  386. @file{PREFIX-N.log}, where N is a number specific to the output
  387. stream
  388. @item -vlang @var{code}
  389. Set the ISO 639 language code (3 letters) of the current video stream.
  390. @item -vf @var{filtergraph} (@emph{output})
  391. Create the filtergraph specified by @var{filtergraph} and use it to
  392. filter the stream.
  393. This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
  394. @end table
  395. @section Advanced Video Options
  396. @table @option
  397. @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
  398. Set pixel format. Use @code{-pix_fmts} to show all the supported
  399. pixel formats.
  400. If the selected pixel format can not be selected, ffmpeg will print a
  401. warning and select the best pixel format supported by the encoder.
  402. If @var{pix_fmt} is prefixed by a @code{+}, ffmpeg will exit with an error
  403. if the requested pixel format can not be selected, and automatic conversions
  404. inside filtergraphs are disabled.
  405. If @var{pix_fmt} is a single @code{+}, ffmpeg selects the same pixel format
  406. as the input (or graph output) and automatic conversions are disabled.
  407. @item -sws_flags @var{flags} (@emph{input/output})
  408. Set SwScaler flags.
  409. @item -vdt @var{n}
  410. Discard threshold.
  411. @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
  412. Rate control override for specific intervals, formatted as "int,int,int"
  413. list separated with slashes. Two first values are the beginning and
  414. end frame numbers, last one is quantizer to use if positive, or quality
  415. factor if negative.
  416. @item -ilme
  417. Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
  418. Use this option if your input file is interlaced and you want
  419. to keep the interlaced format for minimum losses.
  420. The alternative is to deinterlace the input stream with
  421. @option{-deinterlace}, but deinterlacing introduces losses.
  422. @item -psnr
  423. Calculate PSNR of compressed frames.
  424. @item -vstats
  425. Dump video coding statistics to @file{vstats_HHMMSS.log}.
  426. @item -vstats_file @var{file}
  427. Dump video coding statistics to @var{file}.
  428. @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
  429. top=1/bottom=0/auto=-1 field first
  430. @item -dc @var{precision}
  431. Intra_dc_precision.
  432. @item -vtag @var{fourcc/tag} (@emph{output})
  433. Force video tag/fourcc. This is an alias for @code{-tag:v}.
  434. @item -qphist (@emph{global})
  435. Show QP histogram
  436. @item -vbsf @var{bitstream_filter}
  437. Deprecated see -bsf
  438. @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
  439. @item -force_key_frames[:@var{stream_specifier}] expr:@var{expr} (@emph{output,per-stream})
  440. Force key frames at the specified timestamps, more precisely at the first
  441. frames after each specified time.
  442. If the argument is prefixed with @code{expr:}, the string @var{expr}
  443. is interpreted like an expression and is evaluated for each frame. A
  444. key frame is forced in case the evaluation is non-zero.
  445. If one of the times is "@code{chapters}[@var{delta}]", it is expanded into
  446. the time of the beginning of all chapters in the file, shifted by
  447. @var{delta}, expressed as a time in seconds.
  448. This option can be useful to ensure that a seek point is present at a
  449. chapter mark or any other designated place in the output file.
  450. For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
  451. before the beginning of every chapter:
  452. @example
  453. -force_key_frames 0:05:00,chapters-0.1
  454. @end example
  455. The expression in @var{expr} can contain the following constants:
  456. @table @option
  457. @item n
  458. the number of current processed frame, starting from 0
  459. @item n_forced
  460. the number of forced frames
  461. @item prev_forced_n
  462. the number of the previous forced frame, it is @code{NAN} when no
  463. keyframe was forced yet
  464. @item prev_forced_t
  465. the time of the previous forced frame, it is @code{NAN} when no
  466. keyframe was forced yet
  467. @item t
  468. the time of the current processed frame
  469. @end table
  470. For example to force a key frame every 5 seconds, you can specify:
  471. @example
  472. -force_key_frames expr:gte(t,n_forced*5)
  473. @end example
  474. To force a key frame 5 seconds after the time of the last forced one,
  475. starting from second 13:
  476. @example
  477. -force_key_frames expr:if(isnan(prev_forced_t),gte(t,13),gte(t,prev_forced_t+5))
  478. @end example
  479. Note that forcing too many keyframes is very harmful for the lookahead
  480. algorithms of certain encoders: using fixed-GOP options or similar
  481. would be more efficient.
  482. @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
  483. When doing stream copy, copy also non-key frames found at the
  484. beginning.
  485. @end table
  486. @section Audio Options
  487. @table @option
  488. @item -aframes @var{number} (@emph{output})
  489. Set the number of audio frames to record. This is an alias for @code{-frames:a}.
  490. @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
  491. Set the audio sampling frequency. For output streams it is set by
  492. default to the frequency of the corresponding input stream. For input
  493. streams this option only makes sense for audio grabbing devices and raw
  494. demuxers and is mapped to the corresponding demuxer options.
  495. @item -aq @var{q} (@emph{output})
  496. Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
  497. @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
  498. Set the number of audio channels. For output streams it is set by
  499. default to the number of input audio channels. For input streams
  500. this option only makes sense for audio grabbing devices and raw demuxers
  501. and is mapped to the corresponding demuxer options.
  502. @item -an (@emph{output})
  503. Disable audio recording.
  504. @item -acodec @var{codec} (@emph{input/output})
  505. Set the audio codec. This is an alias for @code{-codec:a}.
  506. @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
  507. Set the audio sample format. Use @code{-sample_fmts} to get a list
  508. of supported sample formats.
  509. @item -af @var{filtergraph} (@emph{output})
  510. Create the filtergraph specified by @var{filtergraph} and use it to
  511. filter the stream.
  512. This is an alias for @code{-filter:a}, see the @ref{filter_option,,-filter option}.
  513. @end table
  514. @section Advanced Audio options:
  515. @table @option
  516. @item -atag @var{fourcc/tag} (@emph{output})
  517. Force audio tag/fourcc. This is an alias for @code{-tag:a}.
  518. @item -absf @var{bitstream_filter}
  519. Deprecated, see -bsf
  520. @item -guess_layout_max @var{channels} (@emph{input,per-stream})
  521. If some input channel layout is not known, try to guess only if it
  522. corresponds to at most the specified number of channels. For example, 2
  523. tells to @command{ffmpeg} to recognize 1 channel as mono and 2 channels as
  524. stereo but not 6 channels as 5.1. The default is to always try to guess. Use
  525. 0 to disable all guessing.
  526. @end table
  527. @section Subtitle options:
  528. @table @option
  529. @item -slang @var{code}
  530. Set the ISO 639 language code (3 letters) of the current subtitle stream.
  531. @item -scodec @var{codec} (@emph{input/output})
  532. Set the subtitle codec. This is an alias for @code{-codec:s}.
  533. @item -sn (@emph{output})
  534. Disable subtitle recording.
  535. @item -sbsf @var{bitstream_filter}
  536. Deprecated, see -bsf
  537. @end table
  538. @section Advanced Subtitle options:
  539. @table @option
  540. @item -fix_sub_duration
  541. Fix subtitles durations. For each subtitle, wait for the next packet in the
  542. same stream and adjust the duration of the first to avoid overlap. This is
  543. necessary with some subtitles codecs, especially DVB subtitles, because the
  544. duration in the original packet is only a rough estimate and the end is
  545. actually marked by an empty subtitle frame. Failing to use this option when
  546. necessary can result in exaggerated durations or muxing failures due to
  547. non-monotonic timestamps.
  548. Note that this option will delay the output of all data until the next
  549. subtitle packet is decoded: it may increase memory consumption and latency a
  550. lot.
  551. @item -canvas_size @var{size}
  552. Set the size of the canvas used to render subtitles.
  553. @end table
  554. @section Advanced options
  555. @table @option
  556. @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
  557. Designate one or more input streams as a source for the output file. Each input
  558. stream is identified by the input file index @var{input_file_id} and
  559. the input stream index @var{input_stream_id} within the input
  560. file. Both indices start at 0. If specified,
  561. @var{sync_file_id}:@var{stream_specifier} sets which input stream
  562. is used as a presentation sync reference.
  563. The first @code{-map} option on the command line specifies the
  564. source for output stream 0, the second @code{-map} option specifies
  565. the source for output stream 1, etc.
  566. A @code{-} character before the stream identifier creates a "negative" mapping.
  567. It disables matching streams from already created mappings.
  568. An alternative @var{[linklabel]} form will map outputs from complex filter
  569. graphs (see the @option{-filter_complex} option) to the output file.
  570. @var{linklabel} must correspond to a defined output link label in the graph.
  571. For example, to map ALL streams from the first input file to output
  572. @example
  573. ffmpeg -i INPUT -map 0 output
  574. @end example
  575. For example, if you have two audio streams in the first input file,
  576. these streams are identified by "0:0" and "0:1". You can use
  577. @code{-map} to select which streams to place in an output file. For
  578. example:
  579. @example
  580. ffmpeg -i INPUT -map 0:1 out.wav
  581. @end example
  582. will map the input stream in @file{INPUT} identified by "0:1" to
  583. the (single) output stream in @file{out.wav}.
  584. For example, to select the stream with index 2 from input file
  585. @file{a.mov} (specified by the identifier "0:2"), and stream with
  586. index 6 from input @file{b.mov} (specified by the identifier "1:6"),
  587. and copy them to the output file @file{out.mov}:
  588. @example
  589. ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
  590. @end example
  591. To select all video and the third audio stream from an input file:
  592. @example
  593. ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
  594. @end example
  595. To map all the streams except the second audio, use negative mappings
  596. @example
  597. ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
  598. @end example
  599. Note that using this option disables the default mappings for this output file.
  600. @item -map_channel [@var{input_file_id}.@var{stream_specifier}.@var{channel_id}|-1][:@var{output_file_id}.@var{stream_specifier}]
  601. Map an audio channel from a given input to an output. If
  602. @var{output_file_id}.@var{stream_specifier} is not set, the audio channel will
  603. be mapped on all the audio streams.
  604. Using "-1" instead of
  605. @var{input_file_id}.@var{stream_specifier}.@var{channel_id} will map a muted
  606. channel.
  607. For example, assuming @var{INPUT} is a stereo audio file, you can switch the
  608. two audio channels with the following command:
  609. @example
  610. ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
  611. @end example
  612. If you want to mute the first channel and keep the second:
  613. @example
  614. ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
  615. @end example
  616. The order of the "-map_channel" option specifies the order of the channels in
  617. the output stream. The output channel layout is guessed from the number of
  618. channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac"
  619. in combination of "-map_channel" makes the channel gain levels to be updated if
  620. input and output channel layouts don't match (for instance two "-map_channel"
  621. options and "-ac 6").
  622. You can also extract each channel of an input to specific outputs; the following
  623. command extracts two channels of the @var{INPUT} audio stream (file 0, stream 0)
  624. to the respective @var{OUTPUT_CH0} and @var{OUTPUT_CH1} outputs:
  625. @example
  626. ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
  627. @end example
  628. The following example splits the channels of a stereo input into two separate
  629. streams, which are put into the same output file:
  630. @example
  631. ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_channel 0.0.0:0.0 -map_channel 0.0.1:0.1 -y out.ogg
  632. @end example
  633. Note that currently each output stream can only contain channels from a single
  634. input stream; you can't for example use "-map_channel" to pick multiple input
  635. audio channels contained in different streams (from the same or different files)
  636. and merge them into a single output stream. It is therefore not currently
  637. possible, for example, to turn two separate mono streams into a single stereo
  638. stream. However splitting a stereo stream into two single channel mono streams
  639. is possible.
  640. If you need this feature, a possible workaround is to use the @emph{amerge}
  641. filter. For example, if you need to merge a media (here @file{input.mkv}) with 2
  642. mono audio streams into one single stereo channel audio stream (and keep the
  643. video stream), you can use the following command:
  644. @example
  645. ffmpeg -i input.mkv -filter_complex "[0:1] [0:2] amerge" -c:a pcm_s16le -c:v copy output.mkv
  646. @end example
  647. @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
  648. Set metadata information of the next output file from @var{infile}. Note that
  649. those are file indices (zero-based), not filenames.
  650. Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
  651. A metadata specifier can have the following forms:
  652. @table @option
  653. @item @var{g}
  654. global metadata, i.e. metadata that applies to the whole file
  655. @item @var{s}[:@var{stream_spec}]
  656. per-stream metadata. @var{stream_spec} is a stream specifier as described
  657. in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
  658. matching stream is copied from. In an output metadata specifier, all matching
  659. streams are copied to.
  660. @item @var{c}:@var{chapter_index}
  661. per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
  662. @item @var{p}:@var{program_index}
  663. per-program metadata. @var{program_index} is the zero-based program index.
  664. @end table
  665. If metadata specifier is omitted, it defaults to global.
  666. By default, global metadata is copied from the first input file,
  667. per-stream and per-chapter metadata is copied along with streams/chapters. These
  668. default mappings are disabled by creating any mapping of the relevant type. A negative
  669. file index can be used to create a dummy mapping that just disables automatic copying.
  670. For example to copy metadata from the first stream of the input file to global metadata
  671. of the output file:
  672. @example
  673. ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
  674. @end example
  675. To do the reverse, i.e. copy global metadata to all audio streams:
  676. @example
  677. ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv
  678. @end example
  679. Note that simple @code{0} would work as well in this example, since global
  680. metadata is assumed by default.
  681. @item -map_chapters @var{input_file_index} (@emph{output})
  682. Copy chapters from input file with index @var{input_file_index} to the next
  683. output file. If no chapter mapping is specified, then chapters are copied from
  684. the first input file with at least one chapter. Use a negative file index to
  685. disable any chapter copying.
  686. @item -benchmark (@emph{global})
  687. Show benchmarking information at the end of an encode.
  688. Shows CPU time used and maximum memory consumption.
  689. Maximum memory consumption is not supported on all systems,
  690. it will usually display as 0 if not supported.
  691. @item -benchmark_all (@emph{global})
  692. Show benchmarking information during the encode.
  693. Shows CPU time used in various steps (audio/video encode/decode).
  694. @item -timelimit @var{duration} (@emph{global})
  695. Exit after ffmpeg has been running for @var{duration} seconds.
  696. @item -dump (@emph{global})
  697. Dump each input packet to stderr.
  698. @item -hex (@emph{global})
  699. When dumping packets, also dump the payload.
  700. @item -re (@emph{input})
  701. Read input at native frame rate. Mainly used to simulate a grab device.
  702. By default @command{ffmpeg} attempts to read the input(s) as fast as possible.
  703. This option will slow down the reading of the input(s) to the native frame rate
  704. of the input(s). It is useful for real-time output (e.g. live streaming). If
  705. your input(s) is coming from some other live streaming source (through HTTP or
  706. UDP for example) the server might already be in real-time, thus the option will
  707. likely not be required. On the other hand, this is meaningful if your input(s)
  708. is a file you are trying to push in real-time.
  709. @item -loop_input
  710. Loop over the input stream. Currently it works only for image
  711. streams. This option is used for automatic FFserver testing.
  712. This option is deprecated, use -loop 1.
  713. @item -loop_output @var{number_of_times}
  714. Repeatedly loop output for formats that support looping such as animated GIF
  715. (0 will loop the output infinitely).
  716. This option is deprecated, use -loop.
  717. @item -vsync @var{parameter}
  718. Video sync method.
  719. For compatibility reasons old values can be specified as numbers.
  720. Newly added values will have to be specified as strings always.
  721. @table @option
  722. @item 0, passthrough
  723. Each frame is passed with its timestamp from the demuxer to the muxer.
  724. @item 1, cfr
  725. Frames will be duplicated and dropped to achieve exactly the requested
  726. constant frame rate.
  727. @item 2, vfr
  728. Frames are passed through with their timestamp or dropped so as to
  729. prevent 2 frames from having the same timestamp.
  730. @item drop
  731. As passthrough but destroys all timestamps, making the muxer generate
  732. fresh timestamps based on frame-rate.
  733. @item -1, auto
  734. Chooses between 1 and 2 depending on muxer capabilities. This is the
  735. default method.
  736. @end table
  737. Note that the timestamps may be further modified by the muxer, after this.
  738. For example, in the case that the format option @option{avoid_negative_ts}
  739. is enabled.
  740. With -map you can select from which stream the timestamps should be
  741. taken. You can leave either video or audio unchanged and sync the
  742. remaining stream(s) to the unchanged one.
  743. @item -async @var{samples_per_second}
  744. Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
  745. the parameter is the maximum samples per second by which the audio is changed.
  746. -async 1 is a special case where only the start of the audio stream is corrected
  747. without any later correction.
  748. Note that the timestamps may be further modified by the muxer, after this.
  749. For example, in the case that the format option @option{avoid_negative_ts}
  750. is enabled.
  751. This option has been deprecated. Use the @code{aresample} audio filter instead.
  752. @item -copyts
  753. Do not process input timestamps, but keep their values without trying
  754. to sanitize them. In particular, do not remove the initial start time
  755. offset value.
  756. Note that, depending on the @option{vsync} option or on specific muxer
  757. processing (e.g. in case the format option @option{avoid_negative_ts}
  758. is enabled) the output timestamps may mismatch with the input
  759. timestamps even when this option is selected.
  760. @item -copytb @var{mode}
  761. Specify how to set the encoder timebase when stream copying. @var{mode} is an
  762. integer numeric value, and can assume one of the following values:
  763. @table @option
  764. @item 1
  765. Use the demuxer timebase.
  766. The time base is copied to the output encoder from the corresponding input
  767. demuxer. This is sometimes required to avoid non monotonically increasing
  768. timestamps when copying video streams with variable frame rate.
  769. @item 0
  770. Use the decoder timebase.
  771. The time base is copied to the output encoder from the corresponding input
  772. decoder.
  773. @item -1
  774. Try to make the choice automatically, in order to generate a sane output.
  775. @end table
  776. Default value is -1.
  777. @item -shortest (@emph{output})
  778. Finish encoding when the shortest input stream ends.
  779. @item -dts_delta_threshold
  780. Timestamp discontinuity delta threshold.
  781. @item -muxdelay @var{seconds} (@emph{input})
  782. Set the maximum demux-decode delay.
  783. @item -muxpreload @var{seconds} (@emph{input})
  784. Set the initial demux-decode delay.
  785. @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
  786. Assign a new stream-id value to an output stream. This option should be
  787. specified prior to the output filename to which it applies.
  788. For the situation where multiple output files exist, a streamid
  789. may be reassigned to a different value.
  790. For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
  791. an output mpegts file:
  792. @example
  793. ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
  794. @end example
  795. @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
  796. Set bitstream filters for matching streams. @var{bitstream_filters} is
  797. a comma-separated list of bitstream filters. Use the @code{-bsfs} option
  798. to get the list of bitstream filters.
  799. @example
  800. ffmpeg -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
  801. @end example
  802. @example
  803. ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
  804. @end example
  805. @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{per-stream})
  806. Force a tag/fourcc for matching streams.
  807. @item -timecode @var{hh}:@var{mm}:@var{ss}SEP@var{ff}
  808. Specify Timecode for writing. @var{SEP} is ':' for non drop timecode and ';'
  809. (or '.') for drop.
  810. @example
  811. ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
  812. @end example
  813. @anchor{filter_complex_option}
  814. @item -filter_complex @var{filtergraph} (@emph{global})
  815. Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
  816. outputs. For simple graphs -- those with one input and one output of the same
  817. type -- see the @option{-filter} options. @var{filtergraph} is a description of
  818. the filtergraph, as described in the ``Filtergraph syntax'' section of the
  819. ffmpeg-filters manual.
  820. Input link labels must refer to input streams using the
  821. @code{[file_index:stream_specifier]} syntax (i.e. the same as @option{-map}
  822. uses). If @var{stream_specifier} matches multiple streams, the first one will be
  823. used. An unlabeled input will be connected to the first unused input stream of
  824. the matching type.
  825. Output link labels are referred to with @option{-map}. Unlabeled outputs are
  826. added to the first output file.
  827. Note that with this option it is possible to use only lavfi sources without
  828. normal input files.
  829. For example, to overlay an image over video
  830. @example
  831. ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
  832. '[out]' out.mkv
  833. @end example
  834. Here @code{[0:v]} refers to the first video stream in the first input file,
  835. which is linked to the first (main) input of the overlay filter. Similarly the
  836. first video stream in the second input is linked to the second (overlay) input
  837. of overlay.
  838. Assuming there is only one video stream in each input file, we can omit input
  839. labels, so the above is equivalent to
  840. @example
  841. ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
  842. '[out]' out.mkv
  843. @end example
  844. Furthermore we can omit the output label and the single output from the filter
  845. graph will be added to the output file automatically, so we can simply write
  846. @example
  847. ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
  848. @end example
  849. To generate 5 seconds of pure red video using lavfi @code{color} source:
  850. @example
  851. ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
  852. @end example
  853. @item -lavfi @var{filtergraph} (@emph{global})
  854. Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
  855. outputs. Equivalent to @option{-filter_complex}.
  856. @item -filter_complex_script @var{filename} (@emph{global})
  857. This option is similar to @option{-filter_complex}, the only difference is that
  858. its argument is the name of the file from which a complex filtergraph
  859. description is to be read.
  860. @item -override_ffserver (@emph{global})
  861. Overrides the input specifications from ffserver. Using this option you can
  862. map any input stream to ffserver and control many aspects of the encoding from
  863. ffmpeg. Without this option ffmpeg will transmit to ffserver what is requested by
  864. ffserver.
  865. The option is intended for cases where features are needed that cannot be
  866. specified to ffserver but can be to ffmpeg.
  867. @end table
  868. As a special exception, you can use a bitmap subtitle stream as input: it
  869. will be converted into a video with the same size as the largest video in
  870. the file, or 720x576 if no video is present. Note that this is an
  871. experimental and temporary solution. It will be removed once libavfilter has
  872. proper support for subtitles.
  873. For example, to hardcode subtitles on top of a DVB-T recording stored in
  874. MPEG-TS format, delaying the subtitles by 1 second:
  875. @example
  876. ffmpeg -i input.ts -filter_complex \
  877. '[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \
  878. -sn -map '#0x2dc' output.mkv
  879. @end example
  880. (0x2d0, 0x2dc and 0x2ef are the MPEG-TS PIDs of respectively the video,
  881. audio and subtitles streams; 0:0, 0:3 and 0:7 would have worked too)
  882. @section Preset files
  883. A preset file contains a sequence of @var{option}=@var{value} pairs,
  884. one for each line, specifying a sequence of options which would be
  885. awkward to specify on the command line. Lines starting with the hash
  886. ('#') character are ignored and are used to provide comments. Check
  887. the @file{presets} directory in the FFmpeg source tree for examples.
  888. Preset files are specified with the @code{vpre}, @code{apre},
  889. @code{spre}, and @code{fpre} options. The @code{fpre} option takes the
  890. filename of the preset instead of a preset name as input and can be
  891. used for any kind of codec. For the @code{vpre}, @code{apre}, and
  892. @code{spre} options, the options specified in a preset file are
  893. applied to the currently selected codec of the same type as the preset
  894. option.
  895. The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
  896. preset options identifies the preset file to use according to the
  897. following rules:
  898. First ffmpeg searches for a file named @var{arg}.ffpreset in the
  899. directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
  900. the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
  901. or in a @file{ffpresets} folder along the executable on win32,
  902. in that order. For example, if the argument is @code{libvpx-1080p}, it will
  903. search for the file @file{libvpx-1080p.ffpreset}.
  904. If no such file is found, then ffmpeg will search for a file named
  905. @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
  906. directories, where @var{codec_name} is the name of the codec to which
  907. the preset file options will be applied. For example, if you select
  908. the video codec with @code{-vcodec libvpx} and use @code{-vpre 1080p},
  909. then it will search for the file @file{libvpx-1080p.ffpreset}.
  910. @c man end OPTIONS
  911. @chapter Tips
  912. @c man begin TIPS
  913. @itemize
  914. @item
  915. For streaming at very low bitrate application, use a low frame rate
  916. and a small GOP size. This is especially true for RealVideo where
  917. the Linux player does not seem to be very fast, so it can miss
  918. frames. An example is:
  919. @example
  920. ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm
  921. @end example
  922. @item
  923. The parameter 'q' which is displayed while encoding is the current
  924. quantizer. The value 1 indicates that a very good quality could
  925. be achieved. The value 31 indicates the worst quality. If q=31 appears
  926. too often, it means that the encoder cannot compress enough to meet
  927. your bitrate. You must either increase the bitrate, decrease the
  928. frame rate or decrease the frame size.
  929. @item
  930. If your computer is not fast enough, you can speed up the
  931. compression at the expense of the compression ratio. You can use
  932. '-me zero' to speed up motion estimation, and '-g 0' to disable
  933. motion estimation completely (you have only I-frames, which means it
  934. is about as good as JPEG compression).
  935. @item
  936. To have very low audio bitrates, reduce the sampling frequency
  937. (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
  938. @item
  939. To have a constant quality (but a variable bitrate), use the option
  940. '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
  941. quality).
  942. @end itemize
  943. @c man end TIPS
  944. @chapter Examples
  945. @c man begin EXAMPLES
  946. @section Preset files
  947. A preset file contains a sequence of @var{option=value} pairs, one for
  948. each line, specifying a sequence of options which can be specified also on
  949. the command line. Lines starting with the hash ('#') character are ignored and
  950. are used to provide comments. Empty lines are also ignored. Check the
  951. @file{presets} directory in the FFmpeg source tree for examples.
  952. Preset files are specified with the @code{pre} option, this option takes a
  953. preset name as input. FFmpeg searches for a file named @var{preset_name}.avpreset in
  954. the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
  955. the data directory defined at configuration time (usually @file{$PREFIX/share/ffmpeg})
  956. in that order. For example, if the argument is @code{libx264-max}, it will
  957. search for the file @file{libx264-max.avpreset}.
  958. @section Video and Audio grabbing
  959. If you specify the input format and device then ffmpeg can grab video
  960. and audio directly.
  961. @example
  962. ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
  963. @end example
  964. Or with an ALSA audio source (mono input, card id 1) instead of OSS:
  965. @example
  966. ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
  967. @end example
  968. Note that you must activate the right video source and channel before
  969. launching ffmpeg with any TV viewer such as
  970. @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
  971. have to set the audio recording levels correctly with a
  972. standard mixer.
  973. @section X11 grabbing
  974. Grab the X11 display with ffmpeg via
  975. @example
  976. ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
  977. @end example
  978. 0.0 is display.screen number of your X11 server, same as
  979. the DISPLAY environment variable.
  980. @example
  981. ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
  982. @end example
  983. 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
  984. variable. 10 is the x-offset and 20 the y-offset for the grabbing.
  985. @section Video and Audio file format conversion
  986. Any supported file format and protocol can serve as input to ffmpeg:
  987. Examples:
  988. @itemize
  989. @item
  990. You can use YUV files as input:
  991. @example
  992. ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
  993. @end example
  994. It will use the files:
  995. @example
  996. /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
  997. /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
  998. @end example
  999. The Y files use twice the resolution of the U and V files. They are
  1000. raw files, without header. They can be generated by all decent video
  1001. decoders. You must specify the size of the image with the @option{-s} option
  1002. if ffmpeg cannot guess it.
  1003. @item
  1004. You can input from a raw YUV420P file:
  1005. @example
  1006. ffmpeg -i /tmp/test.yuv /tmp/out.avi
  1007. @end example
  1008. test.yuv is a file containing raw YUV planar data. Each frame is composed
  1009. of the Y plane followed by the U and V planes at half vertical and
  1010. horizontal resolution.
  1011. @item
  1012. You can output to a raw YUV420P file:
  1013. @example
  1014. ffmpeg -i mydivx.avi hugefile.yuv
  1015. @end example
  1016. @item
  1017. You can set several input files and output files:
  1018. @example
  1019. ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
  1020. @end example
  1021. Converts the audio file a.wav and the raw YUV video file a.yuv
  1022. to MPEG file a.mpg.
  1023. @item
  1024. You can also do audio and video conversions at the same time:
  1025. @example
  1026. ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
  1027. @end example
  1028. Converts a.wav to MPEG audio at 22050 Hz sample rate.
  1029. @item
  1030. You can encode to several formats at the same time and define a
  1031. mapping from input stream to output streams:
  1032. @example
  1033. ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
  1034. @end example
  1035. Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
  1036. file:index' specifies which input stream is used for each output
  1037. stream, in the order of the definition of output streams.
  1038. @item
  1039. You can transcode decrypted VOBs:
  1040. @example
  1041. ffmpeg -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi
  1042. @end example
  1043. This is a typical DVD ripping example; the input is a VOB file, the
  1044. output an AVI file with MPEG-4 video and MP3 audio. Note that in this
  1045. command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
  1046. GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
  1047. input video. Furthermore, the audio stream is MP3-encoded so you need
  1048. to enable LAME support by passing @code{--enable-libmp3lame} to configure.
  1049. The mapping is particularly useful for DVD transcoding
  1050. to get the desired audio language.
  1051. NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
  1052. @item
  1053. You can extract images from a video, or create a video from many images:
  1054. For extracting images from a video:
  1055. @example
  1056. ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
  1057. @end example
  1058. This will extract one video frame per second from the video and will
  1059. output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
  1060. etc. Images will be rescaled to fit the new WxH values.
  1061. If you want to extract just a limited number of frames, you can use the
  1062. above command in combination with the -vframes or -t option, or in
  1063. combination with -ss to start extracting from a certain point in time.
  1064. For creating a video from many images:
  1065. @example
  1066. ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
  1067. @end example
  1068. The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
  1069. composed of three digits padded with zeroes to express the sequence
  1070. number. It is the same syntax supported by the C printf function, but
  1071. only formats accepting a normal integer are suitable.
  1072. When importing an image sequence, -i also supports expanding
  1073. shell-like wildcard patterns (globbing) internally, by selecting the
  1074. image2-specific @code{-pattern_type glob} option.
  1075. For example, for creating a video from filenames matching the glob pattern
  1076. @code{foo-*.jpeg}:
  1077. @example
  1078. ffmpeg -f image2 -pattern_type glob -i 'foo-*.jpeg' -r 12 -s WxH foo.avi
  1079. @end example
  1080. @item
  1081. You can put many streams of the same type in the output:
  1082. @example
  1083. ffmpeg -i test1.avi -i test2.avi -map 0:3 -map 0:2 -map 0:1 -map 0:0 -c copy test12.nut
  1084. @end example
  1085. The resulting output file @file{test12.avi} will contain first four streams from
  1086. the input file in reverse order.
  1087. @item
  1088. To force CBR video output:
  1089. @example
  1090. ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
  1091. @end example
  1092. @item
  1093. The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
  1094. but you may use the QP2LAMBDA constant to easily convert from 'q' units:
  1095. @example
  1096. ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
  1097. @end example
  1098. @end itemize
  1099. @c man end EXAMPLES
  1100. @include config.texi
  1101. @ifset config-all
  1102. @ifset config-avutil
  1103. @include utils.texi
  1104. @end ifset
  1105. @ifset config-avcodec
  1106. @include codecs.texi
  1107. @include bitstream_filters.texi
  1108. @end ifset
  1109. @ifset config-avformat
  1110. @include formats.texi
  1111. @include protocols.texi
  1112. @end ifset
  1113. @ifset config-avdevice
  1114. @include devices.texi
  1115. @end ifset
  1116. @ifset config-swresample
  1117. @include resampler.texi
  1118. @end ifset
  1119. @ifset config-swscale
  1120. @include scaler.texi
  1121. @end ifset
  1122. @ifset config-avfilter
  1123. @include filters.texi
  1124. @end ifset
  1125. @end ifset
  1126. @chapter See Also
  1127. @ifhtml
  1128. @ifset config-all
  1129. @url{ffmpeg.html,ffmpeg}
  1130. @end ifset
  1131. @ifset config-not-all
  1132. @url{ffmpeg-all.html,ffmpeg-all},
  1133. @end ifset
  1134. @url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe}, @url{ffserver.html,ffserver},
  1135. @url{ffmpeg-utils.html,ffmpeg-utils},
  1136. @url{ffmpeg-scaler.html,ffmpeg-scaler},
  1137. @url{ffmpeg-resampler.html,ffmpeg-resampler},
  1138. @url{ffmpeg-codecs.html,ffmpeg-codecs},
  1139. @url{ffmpeg-bitstream-filters.html,ffmpeg-bitstream-filters},
  1140. @url{ffmpeg-formats.html,ffmpeg-formats},
  1141. @url{ffmpeg-devices.html,ffmpeg-devices},
  1142. @url{ffmpeg-protocols.html,ffmpeg-protocols},
  1143. @url{ffmpeg-filters.html,ffmpeg-filters}
  1144. @end ifhtml
  1145. @ifnothtml
  1146. @ifset config-all
  1147. ffmpeg(1),
  1148. @end ifset
  1149. @ifset config-not-all
  1150. ffmpeg-all(1),
  1151. @end ifset
  1152. ffplay(1), ffprobe(1), ffserver(1),
  1153. ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1),
  1154. ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1),
  1155. ffmpeg-devices(1), ffmpeg-protocols(1), ffmpeg-filters(1)
  1156. @end ifnothtml
  1157. @include authors.texi
  1158. @ignore
  1159. @setfilename ffmpeg
  1160. @settitle ffmpeg video converter
  1161. @end ignore
  1162. @bye