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  1. \input texinfo @c -*- texinfo -*-
  2. @settitle FFmpeg Documentation
  3. @titlepage
  4. @sp 7
  5. @center @titlefont{FFmpeg Documentation}
  6. @sp 3
  7. @end titlepage
  8. @chapter Synopsis
  9. The generic syntax is:
  10. @example
  11. @c man begin SYNOPSIS
  12. ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
  13. @c man end
  14. @end example
  15. @chapter Description
  16. @c man begin DESCRIPTION
  17. FFmpeg is a very fast video and audio converter. It can also grab from
  18. a live audio/video source.
  19. The command line interface is designed to be intuitive, in the sense
  20. that FFmpeg tries to figure out all parameters that can possibly be
  21. derived automatically. You usually only have to specify the target
  22. bitrate you want.
  23. FFmpeg can also convert from any sample rate to any other, and resize
  24. video on the fly with a high quality polyphase filter.
  25. As a general rule, options are applied to the next specified
  26. file. Therefore, order is important, and you can have the same
  27. option on the command line multiple times. Each occurrence is
  28. then applied to the next input or output file.
  29. * To set the video bitrate of the output file to 64kbit/s:
  30. @example
  31. ffmpeg -i input.avi -b 64k output.avi
  32. @end example
  33. * To force the frame rate of the output file to 24 fps:
  34. @example
  35. ffmpeg -i input.avi -r 24 output.avi
  36. @end example
  37. * To force the frame rate of the input file (valid for raw formats only)
  38. to 1 fps and the frame rate of the output file to 24 fps:
  39. @example
  40. ffmpeg -r 1 -i input.m2v -r 24 output.avi
  41. @end example
  42. The format option may be needed for raw input files.
  43. By default, FFmpeg tries to convert as losslessly as possible: It
  44. uses the same audio and video parameters for the outputs as the one
  45. specified for the inputs.
  46. @c man end DESCRIPTION
  47. @chapter Options
  48. @c man begin OPTIONS
  49. @include fftools-common-opts.texi
  50. @section Main options
  51. @table @option
  52. @item -f @var{fmt}
  53. Force format.
  54. @item -i @var{filename}
  55. input file name
  56. @item -y
  57. Overwrite output files.
  58. @item -t @var{duration}
  59. Restrict the transcoded/captured video sequence
  60. to the duration specified in seconds.
  61. @code{hh:mm:ss[.xxx]} syntax is also supported.
  62. @item -fs @var{limit_size}
  63. Set the file size limit.
  64. @item -ss @var{position}
  65. Seek to given time position in seconds.
  66. @code{hh:mm:ss[.xxx]} syntax is also supported.
  67. @item -itsoffset @var{offset}
  68. Set the input time offset in seconds.
  69. @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
  70. This option affects all the input files that follow it.
  71. The offset is added to the timestamps of the input files.
  72. Specifying a positive offset means that the corresponding
  73. streams are delayed by 'offset' seconds.
  74. @item -timestamp @var{time}
  75. Set the recording timestamp in the container.
  76. The syntax for @var{time} is:
  77. @example
  78. now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
  79. @end example
  80. If the value is "now" it takes the current time.
  81. Time is local time unless 'Z' or 'z' is appended, in which case it is
  82. interpreted as UTC.
  83. If the year-month-day part is not specified it takes the current
  84. year-month-day.
  85. @item -metadata @var{key}=@var{value}
  86. Set a metadata key/value pair.
  87. For example, for setting the title in the output file:
  88. @example
  89. ffmpeg -i in.avi -metadata title="my title" out.flv
  90. @end example
  91. @item -v @var{number}
  92. Set the logging verbosity level.
  93. @item -target @var{type}
  94. Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
  95. "ntsc-svcd", ... ). All the format options (bitrate, codecs,
  96. buffer sizes) are then set automatically. You can just type:
  97. @example
  98. ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
  99. @end example
  100. Nevertheless you can specify additional options as long as you know
  101. they do not conflict with the standard, as in:
  102. @example
  103. ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
  104. @end example
  105. @item -dframes @var{number}
  106. Set the number of data frames to record.
  107. @item -scodec @var{codec}
  108. Force subtitle codec ('copy' to copy stream).
  109. @item -newsubtitle
  110. Add a new subtitle stream to the current output stream.
  111. @item -slang @var{code}
  112. Set the ISO 639 language code (3 letters) of the current subtitle stream.
  113. @end table
  114. @section Video Options
  115. @table @option
  116. @item -b @var{bitrate}
  117. Set the video bitrate in bit/s (default = 200 kb/s).
  118. @item -vframes @var{number}
  119. Set the number of video frames to record.
  120. @item -r @var{fps}
  121. Set frame rate (Hz value, fraction or abbreviation), (default = 25).
  122. @item -s @var{size}
  123. Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
  124. The following abbreviations are recognized:
  125. @table @samp
  126. @item sqcif
  127. 128x96
  128. @item qcif
  129. 176x144
  130. @item cif
  131. 352x288
  132. @item 4cif
  133. 704x576
  134. @item 16cif
  135. 1408x1152
  136. @item qqvga
  137. 160x120
  138. @item qvga
  139. 320x240
  140. @item vga
  141. 640x480
  142. @item svga
  143. 800x600
  144. @item xga
  145. 1024x768
  146. @item uxga
  147. 1600x1200
  148. @item qxga
  149. 2048x1536
  150. @item sxga
  151. 1280x1024
  152. @item qsxga
  153. 2560x2048
  154. @item hsxga
  155. 5120x4096
  156. @item wvga
  157. 852x480
  158. @item wxga
  159. 1366x768
  160. @item wsxga
  161. 1600x1024
  162. @item wuxga
  163. 1920x1200
  164. @item woxga
  165. 2560x1600
  166. @item wqsxga
  167. 3200x2048
  168. @item wquxga
  169. 3840x2400
  170. @item whsxga
  171. 6400x4096
  172. @item whuxga
  173. 7680x4800
  174. @item cga
  175. 320x200
  176. @item ega
  177. 640x350
  178. @item hd480
  179. 852x480
  180. @item hd720
  181. 1280x720
  182. @item hd1080
  183. 1920x1080
  184. @end table
  185. @item -aspect @var{aspect}
  186. Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
  187. @item -croptop @var{size} (deprecated - use -vf crop=x:y:width:height instead)
  188. Set top crop band size (in pixels).
  189. @item -cropbottom @var{size} (deprecated - use -vf crop=x:y:width:height instead)
  190. Set bottom crop band size (in pixels).
  191. @item -cropleft @var{size} (deprecated - use -vf crop=x:y:width:height instead)
  192. Set left crop band size (in pixels).
  193. @item -cropright @var{size} (deprecated - use -vf crop=x:y:width:height instead)
  194. Set right crop band size (in pixels).
  195. @item -padtop @var{size}
  196. @item -padbottom @var{size}
  197. @item -padleft @var{size}
  198. @item -padright @var{size}
  199. @item -padcolor @var{hex_color}
  200. All the pad options have been removed. Use -vf
  201. pad=width:height:x:y:color instead.
  202. @item -vn
  203. Disable video recording.
  204. @item -bt @var{tolerance}
  205. Set video bitrate tolerance (in bits, default 4000k).
  206. Has a minimum value of: (target_bitrate/target_framerate).
  207. In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
  208. willing to deviate from the target average bitrate value. This is
  209. not related to min/max bitrate. Lowering tolerance too much has
  210. an adverse effect on quality.
  211. @item -maxrate @var{bitrate}
  212. Set max video bitrate (in bit/s).
  213. Requires -bufsize to be set.
  214. @item -minrate @var{bitrate}
  215. Set min video bitrate (in bit/s).
  216. Most useful in setting up a CBR encode:
  217. @example
  218. ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
  219. @end example
  220. It is of little use elsewise.
  221. @item -bufsize @var{size}
  222. Set video buffer verifier buffer size (in bits).
  223. @item -vcodec @var{codec}
  224. Force video codec to @var{codec}. Use the @code{copy} special value to
  225. tell that the raw codec data must be copied as is.
  226. @item -sameq
  227. Use same video quality as source (implies VBR).
  228. @item -pass @var{n}
  229. Select the pass number (1 or 2). It is used to do two-pass
  230. video encoding. The statistics of the video are recorded in the first
  231. pass into a log file (see also the option -passlogfile),
  232. and in the second pass that log file is used to generate the video
  233. at the exact requested bitrate.
  234. On pass 1, you may just deactivate audio and set output to null,
  235. examples for Windows and Unix:
  236. @example
  237. ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
  238. ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
  239. @end example
  240. @item -passlogfile @var{prefix}
  241. Set two-pass log file name prefix to @var{prefix}, the default file name
  242. prefix is ``ffmpeg2pass''. The complete file name will be
  243. @file{PREFIX-N.log}, where N is a number specific to the output
  244. stream.
  245. @item -newvideo
  246. Add a new video stream to the current output stream.
  247. @item -vlang @var{code}
  248. Set the ISO 639 language code (3 letters) of the current video stream.
  249. @item -vf @var{filter_graph}
  250. @var{filter_graph} is a description of the filter graph to apply to
  251. the input video.
  252. Use the option "-filters" to show all the available filters (including
  253. also sources and sinks).
  254. @end table
  255. @section Advanced Video Options
  256. @table @option
  257. @item -pix_fmt @var{format}
  258. Set pixel format. Use 'list' as parameter to show all the supported
  259. pixel formats.
  260. @item -sws_flags @var{flags}
  261. Set SwScaler flags.
  262. @item -g @var{gop_size}
  263. Set the group of pictures size.
  264. @item -intra
  265. Use only intra frames.
  266. @item -vdt @var{n}
  267. Discard threshold.
  268. @item -qscale @var{q}
  269. Use fixed video quantizer scale (VBR).
  270. @item -qmin @var{q}
  271. minimum video quantizer scale (VBR)
  272. @item -qmax @var{q}
  273. maximum video quantizer scale (VBR)
  274. @item -qdiff @var{q}
  275. maximum difference between the quantizer scales (VBR)
  276. @item -qblur @var{blur}
  277. video quantizer scale blur (VBR) (range 0.0 - 1.0)
  278. @item -qcomp @var{compression}
  279. video quantizer scale compression (VBR) (default 0.5).
  280. Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
  281. @item -lmin @var{lambda}
  282. minimum video lagrange factor (VBR)
  283. @item -lmax @var{lambda}
  284. max video lagrange factor (VBR)
  285. @item -mblmin @var{lambda}
  286. minimum macroblock quantizer scale (VBR)
  287. @item -mblmax @var{lambda}
  288. maximum macroblock quantizer scale (VBR)
  289. These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
  290. but you may use the QP2LAMBDA constant to easily convert from 'q' units:
  291. @example
  292. ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
  293. @end example
  294. @item -rc_init_cplx @var{complexity}
  295. initial complexity for single pass encoding
  296. @item -b_qfactor @var{factor}
  297. qp factor between P- and B-frames
  298. @item -i_qfactor @var{factor}
  299. qp factor between P- and I-frames
  300. @item -b_qoffset @var{offset}
  301. qp offset between P- and B-frames
  302. @item -i_qoffset @var{offset}
  303. qp offset between P- and I-frames
  304. @item -rc_eq @var{equation}
  305. Set rate control equation (@pxref{FFmpeg formula
  306. evaluator}) (default = @code{tex^qComp}).
  307. @item -rc_override @var{override}
  308. rate control override for specific intervals
  309. @item -me_method @var{method}
  310. Set motion estimation method to @var{method}.
  311. Available methods are (from lowest to best quality):
  312. @table @samp
  313. @item zero
  314. Try just the (0, 0) vector.
  315. @item phods
  316. @item log
  317. @item x1
  318. @item hex
  319. @item umh
  320. @item epzs
  321. (default method)
  322. @item full
  323. exhaustive search (slow and marginally better than epzs)
  324. @end table
  325. @item -dct_algo @var{algo}
  326. Set DCT algorithm to @var{algo}. Available values are:
  327. @table @samp
  328. @item 0
  329. FF_DCT_AUTO (default)
  330. @item 1
  331. FF_DCT_FASTINT
  332. @item 2
  333. FF_DCT_INT
  334. @item 3
  335. FF_DCT_MMX
  336. @item 4
  337. FF_DCT_MLIB
  338. @item 5
  339. FF_DCT_ALTIVEC
  340. @end table
  341. @item -idct_algo @var{algo}
  342. Set IDCT algorithm to @var{algo}. Available values are:
  343. @table @samp
  344. @item 0
  345. FF_IDCT_AUTO (default)
  346. @item 1
  347. FF_IDCT_INT
  348. @item 2
  349. FF_IDCT_SIMPLE
  350. @item 3
  351. FF_IDCT_SIMPLEMMX
  352. @item 4
  353. FF_IDCT_LIBMPEG2MMX
  354. @item 5
  355. FF_IDCT_PS2
  356. @item 6
  357. FF_IDCT_MLIB
  358. @item 7
  359. FF_IDCT_ARM
  360. @item 8
  361. FF_IDCT_ALTIVEC
  362. @item 9
  363. FF_IDCT_SH4
  364. @item 10
  365. FF_IDCT_SIMPLEARM
  366. @end table
  367. @item -er @var{n}
  368. Set error resilience to @var{n}.
  369. @table @samp
  370. @item 1
  371. FF_ER_CAREFUL (default)
  372. @item 2
  373. FF_ER_COMPLIANT
  374. @item 3
  375. FF_ER_AGGRESSIVE
  376. @item 4
  377. FF_ER_VERY_AGGRESSIVE
  378. @end table
  379. @item -ec @var{bit_mask}
  380. Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
  381. the following values:
  382. @table @samp
  383. @item 1
  384. FF_EC_GUESS_MVS (default = enabled)
  385. @item 2
  386. FF_EC_DEBLOCK (default = enabled)
  387. @end table
  388. @item -bf @var{frames}
  389. Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
  390. @item -mbd @var{mode}
  391. macroblock decision
  392. @table @samp
  393. @item 0
  394. FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
  395. @item 1
  396. FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
  397. @item 2
  398. FF_MB_DECISION_RD: rate distortion
  399. @end table
  400. @item -4mv
  401. Use four motion vector by macroblock (MPEG-4 only).
  402. @item -part
  403. Use data partitioning (MPEG-4 only).
  404. @item -bug @var{param}
  405. Work around encoder bugs that are not auto-detected.
  406. @item -strict @var{strictness}
  407. How strictly to follow the standards.
  408. @item -aic
  409. Enable Advanced intra coding (h263+).
  410. @item -umv
  411. Enable Unlimited Motion Vector (h263+)
  412. @item -deinterlace
  413. Deinterlace pictures.
  414. @item -ilme
  415. Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
  416. Use this option if your input file is interlaced and you want
  417. to keep the interlaced format for minimum losses.
  418. The alternative is to deinterlace the input stream with
  419. @option{-deinterlace}, but deinterlacing introduces losses.
  420. @item -psnr
  421. Calculate PSNR of compressed frames.
  422. @item -vstats
  423. Dump video coding statistics to @file{vstats_HHMMSS.log}.
  424. @item -vstats_file @var{file}
  425. Dump video coding statistics to @var{file}.
  426. @item -top @var{n}
  427. top=1/bottom=0/auto=-1 field first
  428. @item -dc @var{precision}
  429. Intra_dc_precision.
  430. @item -vtag @var{fourcc/tag}
  431. Force video tag/fourcc.
  432. @item -qphist
  433. Show QP histogram.
  434. @item -vbsf @var{bitstream_filter}
  435. Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
  436. @example
  437. ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
  438. @end example
  439. @end table
  440. @section Audio Options
  441. @table @option
  442. @item -aframes @var{number}
  443. Set the number of audio frames to record.
  444. @item -ar @var{freq}
  445. Set the audio sampling frequency (default = 44100 Hz).
  446. @item -ab @var{bitrate}
  447. Set the audio bitrate in bit/s (default = 64k).
  448. @item -aq @var{q}
  449. Set the audio quality (codec-specific, VBR).
  450. @item -ac @var{channels}
  451. Set the number of audio channels (default = 1).
  452. @item -an
  453. Disable audio recording.
  454. @item -acodec @var{codec}
  455. Force audio codec to @var{codec}. Use the @code{copy} special value to
  456. specify that the raw codec data must be copied as is.
  457. @item -newaudio
  458. Add a new audio track to the output file. If you want to specify parameters,
  459. do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
  460. Mapping will be done automatically, if the number of output streams is equal to
  461. the number of input streams, else it will pick the first one that matches. You
  462. can override the mapping using @code{-map} as usual.
  463. Example:
  464. @example
  465. ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
  466. @end example
  467. @item -alang @var{code}
  468. Set the ISO 639 language code (3 letters) of the current audio stream.
  469. @end table
  470. @section Advanced Audio options:
  471. @table @option
  472. @item -atag @var{fourcc/tag}
  473. Force audio tag/fourcc.
  474. @item -absf @var{bitstream_filter}
  475. Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
  476. @end table
  477. @section Subtitle options:
  478. @table @option
  479. @item -scodec @var{codec}
  480. Force subtitle codec ('copy' to copy stream).
  481. @item -newsubtitle
  482. Add a new subtitle stream to the current output stream.
  483. @item -slang @var{code}
  484. Set the ISO 639 language code (3 letters) of the current subtitle stream.
  485. @item -sn
  486. Disable subtitle recording.
  487. @item -sbsf @var{bitstream_filter}
  488. Bitstream filters available are "mov2textsub", "text2movsub".
  489. @example
  490. ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
  491. @end example
  492. @end table
  493. @section Audio/Video grab options
  494. @table @option
  495. @item -vc @var{channel}
  496. Set video grab channel (DV1394 only).
  497. @item -tvstd @var{standard}
  498. Set television standard (NTSC, PAL (SECAM)).
  499. @item -isync
  500. Synchronize read on input.
  501. @end table
  502. @section Advanced options
  503. @table @option
  504. @item -map @var{input_stream_id}[:@var{sync_stream_id}]
  505. Set stream mapping from input streams to output streams.
  506. Just enumerate the input streams in the order you want them in the output.
  507. @var{sync_stream_id} if specified sets the input stream to sync
  508. against.
  509. @item -map_meta_data @var{outfile}:@var{infile}
  510. Set meta data information of @var{outfile} from @var{infile}.
  511. @item -debug
  512. Print specific debug info.
  513. @item -benchmark
  514. Show benchmarking information at the end of an encode.
  515. Shows CPU time used and maximum memory consumption.
  516. Maximum memory consumption is not supported on all systems,
  517. it will usually display as 0 if not supported.
  518. @item -dump
  519. Dump each input packet.
  520. @item -hex
  521. When dumping packets, also dump the payload.
  522. @item -bitexact
  523. Only use bit exact algorithms (for codec testing).
  524. @item -ps @var{size}
  525. Set RTP payload size in bytes.
  526. @item -re
  527. Read input at native frame rate. Mainly used to simulate a grab device.
  528. @item -loop_input
  529. Loop over the input stream. Currently it works only for image
  530. streams. This option is used for automatic FFserver testing.
  531. @item -loop_output @var{number_of_times}
  532. Repeatedly loop output for formats that support looping such as animated GIF
  533. (0 will loop the output infinitely).
  534. @item -threads @var{count}
  535. Thread count.
  536. @item -vsync @var{parameter}
  537. Video sync method.
  538. 0 Each frame is passed with its timestamp from the demuxer to the muxer
  539. 1 Frames will be duplicated and dropped to achieve exactly the requested
  540. constant framerate.
  541. 2 Frames are passed through with their timestamp or dropped so as to prevent
  542. 2 frames from having the same timestamp
  543. -1 Chooses between 1 and 2 depending on muxer capabilities. This is the default method.
  544. With -map you can select from
  545. which stream the timestamps should be taken. You can leave either video or
  546. audio unchanged and sync the remaining stream(s) to the unchanged one.
  547. @item -async @var{samples_per_second}
  548. Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
  549. the parameter is the maximum samples per second by which the audio is changed.
  550. -async 1 is a special case where only the start of the audio stream is corrected
  551. without any later correction.
  552. @item -copyts
  553. Copy timestamps from input to output.
  554. @item -shortest
  555. Finish encoding when the shortest input stream ends.
  556. @item -dts_delta_threshold
  557. Timestamp discontinuity delta threshold.
  558. @item -muxdelay @var{seconds}
  559. Set the maximum demux-decode delay.
  560. @item -muxpreload @var{seconds}
  561. Set the initial demux-decode delay.
  562. @item -streamid @var{output-stream-index}:@var{new-value}
  563. Assign a new value to a stream's stream-id field in the next output file.
  564. All stream-id fields are reset to default for each output file.
  565. For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
  566. an output mpegts file:
  567. @example
  568. ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
  569. @end example
  570. @end table
  571. @section Preset files
  572. A preset file contains a sequence of @var{option}=@var{value} pairs,
  573. one for each line, specifying a sequence of options which would be
  574. awkward to specify on the command line. Lines starting with the hash
  575. ('#') character are ignored and are used to provide comments. Check
  576. the @file{ffpresets} directory in the FFmpeg source tree for examples.
  577. Preset files are specified with the @code{vpre}, @code{apre},
  578. @code{spre}, and @code{fpre} options. The @code{fpre} option takes the
  579. filename of the preset instead of a preset name as input and can be
  580. used for any kind of codec. For the @code{vpre}, @code{apre}, and
  581. @code{spre} options, the options specified in a preset file are
  582. applied to the currently selected codec of the same type as the preset
  583. option.
  584. The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
  585. preset options identifies the preset file to use according to the
  586. following rules:
  587. First ffmpeg searches for a file named @var{arg}.ffpreset in the
  588. directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
  589. the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
  590. in that order. For example, if the argument is @code{libx264-max}, it will
  591. search for the file @file{libx264-max.ffpreset}.
  592. If no such file is found, then ffmpeg will search for a file named
  593. @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
  594. directories, where @var{codec_name} is the name of the codec to which
  595. the preset file options will be applied. For example, if you select
  596. the video codec with @code{-vcodec libx264} and use @code{-vpre max},
  597. then it will search for the file @file{libx264-max.ffpreset}.
  598. @anchor{FFmpeg formula evaluator}
  599. @section FFmpeg formula evaluator
  600. When evaluating a rate control string, FFmpeg uses an internal formula
  601. evaluator.
  602. The following binary operators are available: @code{+}, @code{-},
  603. @code{*}, @code{/}, @code{^}.
  604. The following unary operators are available: @code{+}, @code{-},
  605. @code{(...)}.
  606. The following statements are available: @code{ld}, @code{st},
  607. @code{while}.
  608. The following functions are available:
  609. @table @var
  610. @item sinh(x)
  611. @item cosh(x)
  612. @item tanh(x)
  613. @item sin(x)
  614. @item cos(x)
  615. @item tan(x)
  616. @item atan(x)
  617. @item asin(x)
  618. @item acos(x)
  619. @item exp(x)
  620. @item log(x)
  621. @item abs(x)
  622. @item squish(x)
  623. @item gauss(x)
  624. @item mod(x, y)
  625. @item max(x, y)
  626. @item min(x, y)
  627. @item eq(x, y)
  628. @item gte(x, y)
  629. @item gt(x, y)
  630. @item lte(x, y)
  631. @item lt(x, y)
  632. @item bits2qp(bits)
  633. @item qp2bits(qp)
  634. @end table
  635. The following constants are available:
  636. @table @var
  637. @item PI
  638. @item E
  639. @item iTex
  640. @item pTex
  641. @item tex
  642. @item mv
  643. @item fCode
  644. @item iCount
  645. @item mcVar
  646. @item var
  647. @item isI
  648. @item isP
  649. @item isB
  650. @item avgQP
  651. @item qComp
  652. @item avgIITex
  653. @item avgPITex
  654. @item avgPPTex
  655. @item avgBPTex
  656. @item avgTex
  657. @end table
  658. @c man end
  659. @chapter Tips
  660. @c man begin TIPS
  661. @itemize
  662. @item
  663. For streaming at very low bitrate application, use a low frame rate
  664. and a small GOP size. This is especially true for RealVideo where
  665. the Linux player does not seem to be very fast, so it can miss
  666. frames. An example is:
  667. @example
  668. ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
  669. @end example
  670. @item
  671. The parameter 'q' which is displayed while encoding is the current
  672. quantizer. The value 1 indicates that a very good quality could
  673. be achieved. The value 31 indicates the worst quality. If q=31 appears
  674. too often, it means that the encoder cannot compress enough to meet
  675. your bitrate. You must either increase the bitrate, decrease the
  676. frame rate or decrease the frame size.
  677. @item
  678. If your computer is not fast enough, you can speed up the
  679. compression at the expense of the compression ratio. You can use
  680. '-me zero' to speed up motion estimation, and '-intra' to disable
  681. motion estimation completely (you have only I-frames, which means it
  682. is about as good as JPEG compression).
  683. @item
  684. To have very low audio bitrates, reduce the sampling frequency
  685. (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
  686. @item
  687. To have a constant quality (but a variable bitrate), use the option
  688. '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
  689. quality).
  690. @item
  691. When converting video files, you can use the '-sameq' option which
  692. uses the same quality factor in the encoder as in the decoder.
  693. It allows almost lossless encoding.
  694. @end itemize
  695. @c man end TIPS
  696. @chapter Examples
  697. @c man begin EXAMPLES
  698. @section Video and Audio grabbing
  699. FFmpeg can grab video and audio from devices given that you specify the input
  700. format and device.
  701. @example
  702. ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
  703. @end example
  704. Note that you must activate the right video source and channel before
  705. launching FFmpeg with any TV viewer such as xawtv
  706. (@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
  707. have to set the audio recording levels correctly with a
  708. standard mixer.
  709. @section X11 grabbing
  710. FFmpeg can grab the X11 display.
  711. @example
  712. ffmpeg -f x11grab -s cif -i :0.0 /tmp/out.mpg
  713. @end example
  714. 0.0 is display.screen number of your X11 server, same as
  715. the DISPLAY environment variable.
  716. @example
  717. ffmpeg -f x11grab -s cif -i :0.0+10,20 /tmp/out.mpg
  718. @end example
  719. 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
  720. variable. 10 is the x-offset and 20 the y-offset for the grabbing.
  721. @section Video and Audio file format conversion
  722. * FFmpeg can use any supported file format and protocol as input:
  723. Examples:
  724. * You can use YUV files as input:
  725. @example
  726. ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
  727. @end example
  728. It will use the files:
  729. @example
  730. /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
  731. /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
  732. @end example
  733. The Y files use twice the resolution of the U and V files. They are
  734. raw files, without header. They can be generated by all decent video
  735. decoders. You must specify the size of the image with the @option{-s} option
  736. if FFmpeg cannot guess it.
  737. * You can input from a raw YUV420P file:
  738. @example
  739. ffmpeg -i /tmp/test.yuv /tmp/out.avi
  740. @end example
  741. test.yuv is a file containing raw YUV planar data. Each frame is composed
  742. of the Y plane followed by the U and V planes at half vertical and
  743. horizontal resolution.
  744. * You can output to a raw YUV420P file:
  745. @example
  746. ffmpeg -i mydivx.avi hugefile.yuv
  747. @end example
  748. * You can set several input files and output files:
  749. @example
  750. ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
  751. @end example
  752. Converts the audio file a.wav and the raw YUV video file a.yuv
  753. to MPEG file a.mpg.
  754. * You can also do audio and video conversions at the same time:
  755. @example
  756. ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
  757. @end example
  758. Converts a.wav to MPEG audio at 22050 Hz sample rate.
  759. * You can encode to several formats at the same time and define a
  760. mapping from input stream to output streams:
  761. @example
  762. ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
  763. @end example
  764. Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
  765. file:index' specifies which input stream is used for each output
  766. stream, in the order of the definition of output streams.
  767. * You can transcode decrypted VOBs:
  768. @example
  769. ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
  770. @end example
  771. This is a typical DVD ripping example; the input is a VOB file, the
  772. output an AVI file with MPEG-4 video and MP3 audio. Note that in this
  773. command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
  774. GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
  775. input video. Furthermore, the audio stream is MP3-encoded so you need
  776. to enable LAME support by passing @code{--enable-libmp3lame} to configure.
  777. The mapping is particularly useful for DVD transcoding
  778. to get the desired audio language.
  779. NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
  780. * You can extract images from a video, or create a video from many images:
  781. For extracting images from a video:
  782. @example
  783. ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
  784. @end example
  785. This will extract one video frame per second from the video and will
  786. output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
  787. etc. Images will be rescaled to fit the new WxH values.
  788. If you want to extract just a limited number of frames, you can use the
  789. above command in combination with the -vframes or -t option, or in
  790. combination with -ss to start extracting from a certain point in time.
  791. For creating a video from many images:
  792. @example
  793. ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
  794. @end example
  795. The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
  796. composed of three digits padded with zeroes to express the sequence
  797. number. It is the same syntax supported by the C printf function, but
  798. only formats accepting a normal integer are suitable.
  799. * You can put many streams of the same type in the output:
  800. @example
  801. ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
  802. @end example
  803. In addition to the first video and audio streams, the resulting
  804. output file @file{test12.avi} will contain the second video
  805. and the second audio stream found in the input streams list.
  806. The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
  807. options have to be specified immediately after the name of the output
  808. file to which you want to add them.
  809. @c man end EXAMPLES
  810. @include indevs.texi
  811. @include outdevs.texi
  812. @include protocols.texi
  813. @include filters.texi
  814. @ignore
  815. @setfilename ffmpeg
  816. @settitle FFmpeg video converter
  817. @c man begin SEEALSO
  818. ffplay(1), ffprobe(1), ffserver(1) and the FFmpeg HTML documentation
  819. @c man end
  820. @c man begin AUTHORS
  821. The FFmpeg developers
  822. @c man end
  823. @end ignore
  824. @bye