ffmpeg.texi 55.5 KB
Newer Older
1 2
\input texinfo @c -*- texinfo -*-

3
@settitle ffmpeg Documentation
4
@titlepage
5
@center @titlefont{ffmpeg Documentation}
6 7
@end titlepage

8 9 10 11
@top

@contents

12 13
@chapter Synopsis

14
ffmpeg [@var{global_options}] @{[@var{input_file_options}] -i @file{input_file}@} ... @{[@var{output_file_options}] @file{output_file}@} ...
15

16 17
@chapter Description
@c man begin DESCRIPTION
18

19
@command{ffmpeg} is a very fast video and audio converter that can also grab from
20 21
a live audio/video source. It can also convert between arbitrary sample
rates and resize video on the fly with a high quality polyphase filter.
22

23
@command{ffmpeg} reads from an arbitrary number of input "files" (which can be regular
Michael Niedermayer's avatar
Michael Niedermayer committed
24 25
files, pipes, network streams, grabbing devices, etc.), specified by the
@code{-i} option, and writes to an arbitrary number of output "files", which are
Michael Niedermayer's avatar
Michael Niedermayer committed
26
specified by a plain output filename. Anything found on the command line which
Michael Niedermayer's avatar
Michael Niedermayer committed
27 28
cannot be interpreted as an option is considered to be an output filename.

29 30 31 32 33
Each input or output file can, in principle, contain any number of streams of
different types (video/audio/subtitle/attachment/data). The allowed number and/or
types of streams may be limited by the container format. Selecting which
streams from which inputs will go into which output is either done automatically
or with the @code{-map} option (see the Stream selection chapter).
Michael Niedermayer's avatar
Michael Niedermayer committed
34 35

To refer to input files in options, you must use their indices (0-based). E.g.
36
the first input file is @code{0}, the second is @code{1}, etc. Similarly, streams
Michael Niedermayer's avatar
Michael Niedermayer committed
37
within a file are referred to by their indices. E.g. @code{2:3} refers to the
38
fourth stream in the third input file. Also see the Stream specifiers chapter.
Michael Niedermayer's avatar
Michael Niedermayer committed
39

40 41 42 43
As a general rule, options are applied to the next specified
file. Therefore, order is important, and you can have the same
option on the command line multiple times. Each occurrence is
then applied to the next input or output file.
44 45
Exceptions from this rule are the global options (e.g. verbosity level),
which should be specified first.
46

Michael Niedermayer's avatar
Michael Niedermayer committed
47 48 49 50
Do not mix input and output files -- first specify all input files, then all
output files. Also do not mix options which belong to different files. All
options apply ONLY to the next input or output file and are reset between files.

51 52
@itemize
@item
53
To set the video bitrate of the output file to 64 kbit/s:
54
@example
rogerdpack's avatar
rogerdpack committed
55
ffmpeg -i input.avi -b:v 64k -bufsize 64k output.avi
56 57
@end example

58 59
@item
To force the frame rate of the output file to 24 fps:
60 61 62 63
@example
ffmpeg -i input.avi -r 24 output.avi
@end example

64 65
@item
To force the frame rate of the input file (valid for raw formats only)
66 67 68 69
to 1 fps and the frame rate of the output file to 24 fps:
@example
ffmpeg -r 1 -i input.m2v -r 24 output.avi
@end example
70
@end itemize
71 72 73 74 75

The format option may be needed for raw input files.

@c man end DESCRIPTION

76 77 78
@chapter Detailed description
@c man begin DETAILED DESCRIPTION

79
The transcoding process in @command{ffmpeg} for each output can be described by
80 81 82 83 84 85 86 87 88 89 90
the following diagram:

@example
 _______              ______________               _________              ______________            ________
|       |            |              |             |         |            |              |          |        |
| input |  demuxer   | encoded data |   decoder   | decoded |  encoder   | encoded data |  muxer   | output |
| file  | ---------> | packets      |  ---------> | frames  | ---------> | packets      | -------> | file   |
|_______|            |______________|             |_________|            |______________|          |________|

@end example

91
@command{ffmpeg} calls the libavformat library (containing demuxers) to read
92
input files and get packets containing encoded data from them. When there are
93
multiple input files, @command{ffmpeg} tries to keep them synchronized by
94 95 96 97 98
tracking lowest timestamp on any active input stream.

Encoded packets are then passed to the decoder (unless streamcopy is selected
for the stream, see further for a description). The decoder produces
uncompressed frames (raw video/PCM audio/...) which can be processed further by
99 100
filtering (see next section). After filtering, the frames are passed to the
encoder, which encodes them and outputs encoded packets. Finally those are
101 102 103
passed to the muxer, which writes the encoded packets to the output file.

@section Filtering
104
Before encoding, @command{ffmpeg} can process raw audio and video frames using
105
filters from the libavfilter library. Several chained filters form a filter
106
graph. @command{ffmpeg} distinguishes between two types of filtergraphs:
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141
simple and complex.

@subsection Simple filtergraphs
Simple filtergraphs are those that have exactly one input and output, both of
the same type. In the above diagram they can be represented by simply inserting
an additional step between decoding and encoding:

@example
 _________                        __________              ______________
|         |                      |          |            |              |
| decoded |  simple filtergraph  | filtered |  encoder   | encoded data |
| frames  | -------------------> | frames   | ---------> | packets      |
|_________|                      |__________|            |______________|

@end example

Simple filtergraphs are configured with the per-stream @option{-filter} option
(with @option{-vf} and @option{-af} aliases for video and audio respectively).
A simple filtergraph for video can look for example like this:

@example
 _______        _____________        _______        _____        ________
|       |      |             |      |       |      |     |      |        |
| input | ---> | deinterlace | ---> | scale | ---> | fps | ---> | output |
|_______|      |_____________|      |_______|      |_____|      |________|

@end example

Note that some filters change frame properties but not frame contents. E.g. the
@code{fps} filter in the example above changes number of frames, but does not
touch the frame contents. Another example is the @code{setpts} filter, which
only sets timestamps and otherwise passes the frames unchanged.

@subsection Complex filtergraphs
Complex filtergraphs are those which cannot be described as simply a linear
142
processing chain applied to one stream. This is the case, for example, when the graph has
143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166
more than one input and/or output, or when output stream type is different from
input. They can be represented with the following diagram:

@example
 _________
|         |
| input 0 |\                    __________
|_________| \                  |          |
             \   _________    /| output 0 |
              \ |         |  / |__________|
 _________     \| complex | /
|         |     |         |/
| input 1 |---->| filter  |\
|_________|     |         | \   __________
               /| graph   |  \ |          |
              / |         |   \| output 1 |
 _________   /  |_________|    |__________|
|         | /
| input 2 |/
|_________|

@end example

Complex filtergraphs are configured with the @option{-filter_complex} option.
167
Note that this option is global, since a complex filtergraph, by its nature,
168 169
cannot be unambiguously associated with a single stream or file.

170 171
The @option{-lavfi} option is equivalent to @option{-filter_complex}.

172 173 174 175 176 177
A trivial example of a complex filtergraph is the @code{overlay} filter, which
has two video inputs and one video output, containing one video overlaid on top
of the other. Its audio counterpart is the @code{amix} filter.

@section Stream copy
Stream copy is a mode selected by supplying the @code{copy} parameter to the
178
@option{-codec} option. It makes @command{ffmpeg} omit the decoding and encoding
179 180
step for the specified stream, so it does only demuxing and muxing. It is useful
for changing the container format or modifying container-level metadata. The
181
diagram above will, in this case, simplify to this:
182 183 184 185 186 187 188 189 190 191 192

@example
 _______              ______________            ________
|       |            |              |          |        |
| input |  demuxer   | encoded data |  muxer   | output |
| file  | ---------> | packets      | -------> | file   |
|_______|            |______________|          |________|

@end example

Since there is no decoding or encoding, it is very fast and there is no quality
193
loss. However, it might not work in some cases because of many factors. Applying
194 195 196 197
filters is obviously also impossible, since filters work on uncompressed data.

@c man end DETAILED DESCRIPTION

198 199 200
@chapter Stream selection
@c man begin STREAM SELECTION

201
By default, @command{ffmpeg} includes only one stream of each type (video, audio, subtitle)
202
present in the input files and adds them to each output file.  It picks the
203 204 205 206
"best" of each based upon the following criteria: for video, it is the stream
with the highest resolution, for audio, it is the stream with the most channels, for
subtitles, it is the first subtitle stream. In the case where several streams of
the same type rate equally, the stream with the lowest index is chosen.
207

208
You can disable some of those defaults by using the @code{-vn/-an/-sn} options. For
209 210 211 212 213
full manual control, use the @code{-map} option, which disables the defaults just
described.

@c man end STREAM SELECTION

214
@chapter Options
215
@c man begin OPTIONS
216

217
@include fftools-common-opts.texi
218

219 220
@section Main options

221
@table @option
222

223
@item -f @var{fmt} (@emph{input/output})
224
Force input or output file format. The format is normally auto detected for input
225
files and guessed from the file extension for output files, so this option is not
226
needed in most cases.
Fabrice Bellard's avatar
Fabrice Bellard committed
227

228
@item -i @var{filename} (@emph{input})
229
input file name
230

231
@item -y (@emph{global})
232
Overwrite output files without asking.
233

234
@item -n (@emph{global})
235 236
Do not overwrite output files, and exit immediately if a specified
output file already exists.
237

238 239 240 241 242
@item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
@itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
Select an encoder (when used before an output file) or a decoder (when used
before an input file) for one or more streams. @var{codec} is the name of a
decoder/encoder or a special value @code{copy} (output only) to indicate that
243
the stream is not to be re-encoded.
244 245 246 247 248 249 250 251 252 253 254 255 256 257 258

For example
@example
ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
@end example
encodes all video streams with libx264 and copies all audio streams.

For each stream, the last matching @code{c} option is applied, so
@example
ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
@end example
will copy all the streams except the second video, which will be encoded with
libx264, and the 138th audio, which will be encoded with libvorbis.

@item -t @var{duration} (@emph{output})
259 260
Stop writing the output after its duration reaches @var{duration}.
@var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
261

262 263 264 265 266 267 268 269
-to and -t are mutually exclusive and -t has priority.

@item -to @var{position} (@emph{output})
Stop writing the output at @var{position}.
@var{position} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.

-to and -t are mutually exclusive and -t has priority.

270
@item -fs @var{limit_size} (@emph{output})
271
Set the file size limit, expressed in bytes.
272

273 274
@item -ss @var{position} (@emph{input/output})
When used as an input option (before @code{-i}), seeks in this input file to
275
@var{position}. Note the in most formats it is not possible to seek exactly, so
276
@command{ffmpeg} will seek to the closest seek point before @var{position}.
277 278 279 280 281 282 283
When transcoding and @option{-accurate_seek} is enabled (the default), this
extra segment between the seek point and @var{position} will be decoded and
discarded. When doing stream copy or when @option{-noaccurate_seek} is used, it
will be preserved.

When used as an output option (before an output filename), decodes but discards
input until the timestamps reach @var{position}.
284

285 286 287
@var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.

@item -itsoffset @var{offset} (@emph{input})
288 289 290 291
Set the input time offset in seconds.
@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
The offset is added to the timestamps of the input files.
Specifying a positive offset means that the corresponding
292
streams are delayed by @var{offset} seconds.
293

294
@item -timestamp @var{time} (@emph{output})
295 296 297
Set the recording timestamp in the container.
The syntax for @var{time} is:
@example
298
now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...])|(HHMMSS[.m...]))[Z|z])
299 300 301 302 303 304
@end example
If the value is "now" it takes the current time.
Time is local time unless 'Z' or 'z' is appended, in which case it is
interpreted as UTC.
If the year-month-day part is not specified it takes the current
year-month-day.
305

306
@item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
Stefano Sabatini's avatar
Stefano Sabatini committed
307
Set a metadata key/value pair.
308

309 310 311 312 313 314 315
An optional @var{metadata_specifier} may be given to set metadata
on streams or chapters. See @code{-map_metadata} documentation for
details.

This option overrides metadata set with @code{-map_metadata}. It is
also possible to delete metadata by using an empty value.

316
For example, for setting the title in the output file:
317
@example
318
ffmpeg -i in.avi -metadata title="my title" out.flv
319
@end example
320

Michael Niedermayer's avatar
Michael Niedermayer committed
321
To set the language of the first audio stream:
322
@example
Michael Niedermayer's avatar
Michael Niedermayer committed
323
ffmpeg -i INPUT -metadata:s:a:1 language=eng OUTPUT
324 325 326
@end example

@item -target @var{type} (@emph{output})
327 328 329 330
Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
@code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
@code{film-} to use the corresponding standard. All the format options
(bitrate, codecs, buffer sizes) are then set automatically. You can just type:
Fabrice Bellard's avatar
Fabrice Bellard committed
331 332 333 334 335

@example
ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
@end example

Diego Biurrun's avatar
Diego Biurrun committed
336 337
Nevertheless you can specify additional options as long as you know
they do not conflict with the standard, as in:
338 339 340 341 342

@example
ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
@end example

343 344
@item -dframes @var{number} (@emph{output})
Set the number of data frames to record. This is an alias for @code{-frames:d}.
345

346 347
@item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
Stop writing to the stream after @var{framecount} frames.
348

349 350
@item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
@itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
351
Use fixed quality scale (VBR). The meaning of @var{q}/@var{qscale} is
352
codec-dependent.
353 354 355 356 357
If @var{qscale} is used without a @var{stream_specifier} then it applies only
to the video stream, this is to maintain compatibility with previous behavior
and as specifying the same codec specific value to 2 different codecs that is
audio and video generally is not what is intended when no stream_specifier is
used.
358

359
@anchor{filter_option}
360 361
@item -filter[:@var{stream_specifier}] @var{filtergraph} (@emph{output,per-stream})
Create the filtergraph specified by @var{filtergraph} and use it to
362 363
filter the stream.

364
@var{filtergraph} is a description of the filtergraph to apply to
365
the stream, and must have a single input and a single output of the
366
same type of the stream. In the filtergraph, the input is associated
367 368 369 370 371
to the label @code{in}, and the output to the label @code{out}. See
the ffmpeg-filters manual for more information about the filtergraph
syntax.

See the @ref{filter_complex_option,,-filter_complex option} if you
372
want to create filtergraphs with multiple inputs and/or outputs.
373

374 375 376 377 378
@item -filter_script[:@var{stream_specifier}] @var{filename} (@emph{output,per-stream})
This option is similar to @option{-filter}, the only difference is that its
argument is the name of the file from which a filtergraph description is to be
read.

Michael Niedermayer's avatar
Michael Niedermayer committed
379 380 381 382
@item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
Specify the preset for matching stream(s).

@item -stats (@emph{global})
383 384
Print encoding progress/statistics. It is on by default, to explicitly
disable it you need to specify @code{-nostats}.
Michael Niedermayer's avatar
Michael Niedermayer committed
385

386 387 388 389 390 391 392 393
@item -progress @var{url} (@emph{global})
Send program-friendly progress information to @var{url}.

Progress information is written approximately every second and at the end of
the encoding process. It is made of "@var{key}=@var{value}" lines. @var{key}
consists of only alphanumeric characters. The last key of a sequence of
progress information is always "progress".

394 395
@item -stdin
Enable interaction on standard input. On by default unless standard input is
396 397
used as an input. To explicitly disable interaction you need to specify
@code{-nostdin}.
398

399 400 401 402
Disabling interaction on standard input is useful, for example, if
ffmpeg is in the background process group. Roughly the same result can
be achieved with @code{ffmpeg ... < /dev/null} but it requires a
shell.
403

404 405 406 407 408 409 410 411
@item -debug_ts (@emph{global})
Print timestamp information. It is off by default. This option is
mostly useful for testing and debugging purposes, and the output
format may change from one version to another, so it should not be
employed by portable scripts.

See also the option @code{-fdebug ts}.

Michael Niedermayer's avatar
Michael Niedermayer committed
412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433
@item -attach @var{filename} (@emph{output})
Add an attachment to the output file. This is supported by a few formats
like Matroska for e.g. fonts used in rendering subtitles. Attachments
are implemented as a specific type of stream, so this option will add
a new stream to the file. It is then possible to use per-stream options
on this stream in the usual way. Attachment streams created with this
option will be created after all the other streams (i.e. those created
with @code{-map} or automatic mappings).

Note that for Matroska you also have to set the mimetype metadata tag:
@example
ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
@end example
(assuming that the attachment stream will be third in the output file).

@item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
Extract the matching attachment stream into a file named @var{filename}. If
@var{filename} is empty, then the value of the @code{filename} metadata tag
will be used.

E.g. to extract the first attachment to a file named 'out.ttf':
@example
434
ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
Michael Niedermayer's avatar
Michael Niedermayer committed
435 436 437
@end example
To extract all attachments to files determined by the @code{filename} tag:
@example
438
ffmpeg -dump_attachment:t "" -i INPUT
Michael Niedermayer's avatar
Michael Niedermayer committed
439 440 441 442 443
@end example

Technical note -- attachments are implemented as codec extradata, so this
option can actually be used to extract extradata from any stream, not just
attachments.
444

445 446 447 448
@end table

@section Video Options

449
@table @option
450 451 452
@item -vframes @var{number} (@emph{output})
Set the number of video frames to record. This is an alias for @code{-frames:v}.
@item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
453 454 455 456 457 458
Set frame rate (Hz value, fraction or abbreviation).

As an input option, ignore any timestamps stored in the file and instead
generate timestamps assuming constant frame rate @var{fps}.

As an output option, duplicate or drop input frames to achieve constant output
459
frame rate @var{fps}.
460

461
@item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
462 463 464 465 466 467 468 469 470 471
Set frame size.

As an input option, this is a shortcut for the @option{video_size} private
option, recognized by some demuxers for which the frame size is either not
stored in the file or is configurable -- e.g. raw video or video grabbers.

As an output option, this inserts the @code{scale} video filter to the
@emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
directly to insert it at the beginning or some other place.

472
The format is @samp{wxh} (default - same as source).
Fabrice Bellard's avatar
Fabrice Bellard committed
473

474
@item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
475 476 477 478 479 480 481
Set the video display aspect ratio specified by @var{aspect}.

@var{aspect} can be a floating point number string, or a string of the
form @var{num}:@var{den}, where @var{num} and @var{den} are the
numerator and denominator of the aspect ratio. For example "4:3",
"16:9", "1.3333", and "1.7777" are valid argument values.

482 483 484 485
If used together with @option{-vcodec copy}, it will affect the aspect ratio
stored at container level, but not the aspect ratio stored in encoded
frames, if it exists.

486
@item -vn (@emph{output})
Diego Biurrun's avatar
Diego Biurrun committed
487
Disable video recording.
488

489 490 491
@item -vcodec @var{codec} (@emph{output})
Set the video codec. This is an alias for @code{-codec:v}.

492
@item -pass[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
493 494 495 496 497
Select the pass number (1 or 2). It is used to do two-pass
video encoding. The statistics of the video are recorded in the first
pass into a log file (see also the option -passlogfile),
and in the second pass that log file is used to generate the video
at the exact requested bitrate.
498 499 500
On pass 1, you may just deactivate audio and set output to null,
examples for Windows and Unix:
@example
501 502
ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
503
@end example
504

505
@item -passlogfile[:@var{stream_specifier}] @var{prefix} (@emph{output,per-stream})
506 507 508
Set two-pass log file name prefix to @var{prefix}, the default file name
prefix is ``ffmpeg2pass''. The complete file name will be
@file{PREFIX-N.log}, where N is a number specific to the output
509
stream
510

511 512 513
@item -vlang @var{code}
Set the ISO 639 language code (3 letters) of the current video stream.

514 515
@item -vf @var{filtergraph} (@emph{output})
Create the filtergraph specified by @var{filtergraph} and use it to
516
filter the stream.
517

518
This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
519 520
@end table

Fabrice Bellard's avatar
Fabrice Bellard committed
521
@section Advanced Video Options
522

523
@table @option
524 525
@item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
Set pixel format. Use @code{-pix_fmts} to show all the supported
526
pixel formats.
527 528 529 530
If the selected pixel format can not be selected, ffmpeg will print a
warning and select the best pixel format supported by the encoder.
If @var{pix_fmt} is prefixed by a @code{+}, ffmpeg will exit with an error
if the requested pixel format can not be selected, and automatic conversions
531
inside filtergraphs are disabled.
532 533 534
If @var{pix_fmt} is a single @code{+}, ffmpeg selects the same pixel format
as the input (or graph output) and automatic conversions are disabled.

535
@item -sws_flags @var{flags} (@emph{input/output})
536
Set SwScaler flags.
537
@item -vdt @var{n}
538
Discard threshold.
Stefano Sabatini's avatar
Stefano Sabatini committed
539

540
@item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
541
Rate control override for specific intervals, formatted as "int,int,int"
542 543 544
list separated with slashes. Two first values are the beginning and
end frame numbers, last one is quantizer to use if positive, or quality
factor if negative.
Fabrice Bellard's avatar
Fabrice Bellard committed
545

546
@item -ilme
Diego Biurrun's avatar
Diego Biurrun committed
547 548 549 550 551
Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
Use this option if your input file is interlaced and you want
to keep the interlaced format for minimum losses.
The alternative is to deinterlace the input stream with
@option{-deinterlace}, but deinterlacing introduces losses.
Fabrice Bellard's avatar
Fabrice Bellard committed
552
@item -psnr
Diego Biurrun's avatar
Diego Biurrun committed
553
Calculate PSNR of compressed frames.
Fabrice Bellard's avatar
Fabrice Bellard committed
554
@item -vstats
Diego Biurrun's avatar
Diego Biurrun committed
555
Dump video coding statistics to @file{vstats_HHMMSS.log}.
556
@item -vstats_file @var{file}
557
Dump video coding statistics to @var{file}.
558
@item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
559
top=1/bottom=0/auto=-1 field first
560
@item -dc @var{precision}
561
Intra_dc_precision.
562 563 564 565
@item -vtag @var{fourcc/tag} (@emph{output})
Force video tag/fourcc. This is an alias for @code{-tag:v}.
@item -qphist (@emph{global})
Show QP histogram
566
@item -vbsf @var{bitstream_filter}
567
Deprecated see -bsf
568

569
@item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
570
@item -force_key_frames[:@var{stream_specifier}] expr:@var{expr} (@emph{output,per-stream})
571 572
Force key frames at the specified timestamps, more precisely at the first
frames after each specified time.
573 574 575 576 577

If the argument is prefixed with @code{expr:}, the string @var{expr}
is interpreted like an expression and is evaluated for each frame. A
key frame is forced in case the evaluation is non-zero.

578 579 580
If one of the times is "@code{chapters}[@var{delta}]", it is expanded into
the time of the beginning of all chapters in the file, shifted by
@var{delta}, expressed as a time in seconds.
581 582
This option can be useful to ensure that a seek point is present at a
chapter mark or any other designated place in the output file.
583 584 585 586 587 588

For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
before the beginning of every chapter:
@example
-force_key_frames 0:05:00,chapters-0.1
@end example
Michael Niedermayer's avatar
Michael Niedermayer committed
589

590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
The expression in @var{expr} can contain the following constants:
@table @option
@item n
the number of current processed frame, starting from 0
@item n_forced
the number of forced frames
@item prev_forced_n
the number of the previous forced frame, it is @code{NAN} when no
keyframe was forced yet
@item prev_forced_t
the time of the previous forced frame, it is @code{NAN} when no
keyframe was forced yet
@item t
the time of the current processed frame
@end table

For example to force a key frame every 5 seconds, you can specify:
@example
-force_key_frames expr:gte(t,n_forced*5)
@end example

To force a key frame 5 seconds after the time of the last forced one,
starting from second 13:
@example
-force_key_frames expr:if(isnan(prev_forced_t),gte(t,13),gte(t,prev_forced_t+5))
@end example

Note that forcing too many keyframes is very harmful for the lookahead
algorithms of certain encoders: using fixed-GOP options or similar
would be more efficient.

Michael Niedermayer's avatar
Michael Niedermayer committed
621 622 623
@item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
When doing stream copy, copy also non-key frames found at the
beginning.
Fabrice Bellard's avatar
Fabrice Bellard committed
624 625 626 627 628
@end table

@section Audio Options

@table @option
629 630 631
@item -aframes @var{number} (@emph{output})
Set the number of audio frames to record. This is an alias for @code{-frames:a}.
@item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
632 633 634 635
Set the audio sampling frequency. For output streams it is set by
default to the frequency of the corresponding input stream. For input
streams this option only makes sense for audio grabbing devices and raw
demuxers and is mapped to the corresponding demuxer options.
636 637 638
@item -aq @var{q} (@emph{output})
Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
@item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
639 640 641 642
Set the number of audio channels. For output streams it is set by
default to the number of input audio channels. For input streams
this option only makes sense for audio grabbing devices and raw demuxers
and is mapped to the corresponding demuxer options.
643
@item -an (@emph{output})
Diego Biurrun's avatar
Diego Biurrun committed
644
Disable audio recording.
645 646 647
@item -acodec @var{codec} (@emph{input/output})
Set the audio codec. This is an alias for @code{-codec:a}.
@item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
Michael Niedermayer's avatar
Michael Niedermayer committed
648
Set the audio sample format. Use @code{-sample_fmts} to get a list
649
of supported sample formats.
650

651 652
@item -af @var{filtergraph} (@emph{output})
Create the filtergraph specified by @var{filtergraph} and use it to
653 654 655
filter the stream.

This is an alias for @code{-filter:a}, see the @ref{filter_option,,-filter option}.
656 657 658 659 660
@end table

@section Advanced Audio options:

@table @option
661 662
@item -atag @var{fourcc/tag} (@emph{output})
Force audio tag/fourcc. This is an alias for @code{-tag:a}.
663
@item -absf @var{bitstream_filter}
664
Deprecated, see -bsf
665 666 667 668 669 670
@item -guess_layout_max @var{channels} (@emph{input,per-stream})
If some input channel layout is not known, try to guess only if it
corresponds to at most the specified number of channels. For example, 2
tells to @command{ffmpeg} to recognize 1 channel as mono and 2 channels as
stereo but not 6 channels as 5.1. The default is to always try to guess. Use
0 to disable all guessing.
671 672 673 674 675
@end table

@section Subtitle options:

@table @option
676
@item -slang @var{code}
677
Set the ISO 639 language code (3 letters) of the current subtitle stream.
678 679 680
@item -scodec @var{codec} (@emph{input/output})
Set the subtitle codec. This is an alias for @code{-codec:s}.
@item -sn (@emph{output})
Diego Biurrun's avatar
Diego Biurrun committed
681
Disable subtitle recording.
682
@item -sbsf @var{bitstream_filter}
683
Deprecated, see -bsf
Fabrice Bellard's avatar
Fabrice Bellard committed
684 685
@end table

686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702
@section Advanced Subtitle options:

@table @option

@item -fix_sub_duration
Fix subtitles durations. For each subtitle, wait for the next packet in the
same stream and adjust the duration of the first to avoid overlap. This is
necessary with some subtitles codecs, especially DVB subtitles, because the
duration in the original packet is only a rough estimate and the end is
actually marked by an empty subtitle frame. Failing to use this option when
necessary can result in exaggerated durations or muxing failures due to
non-monotonic timestamps.

Note that this option will delay the output of all data until the next
subtitle packet is decoded: it may increase memory consumption and latency a
lot.

703 704 705
@item -canvas_size @var{size}
Set the size of the canvas used to render subtitles.

706 707
@end table

Fabrice Bellard's avatar
Fabrice Bellard committed
708 709 710
@section Advanced options

@table @option
711
@item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
712

713
Designate one or more input streams as a source for the output file. Each input
714 715
stream is identified by the input file index @var{input_file_id} and
the input stream index @var{input_stream_id} within the input
716 717
file. Both indices start at 0. If specified,
@var{sync_file_id}:@var{stream_specifier} sets which input stream
718 719
is used as a presentation sync reference.

720
The first @code{-map} option on the command line specifies the
721 722 723
source for output stream 0, the second @code{-map} option specifies
the source for output stream 1, etc.

724 725 726
A @code{-} character before the stream identifier creates a "negative" mapping.
It disables matching streams from already created mappings.

727 728 729 730
An alternative @var{[linklabel]} form will map outputs from complex filter
graphs (see the @option{-filter_complex} option) to the output file.
@var{linklabel} must correspond to a defined output link label in the graph.

731 732 733 734 735
For example, to map ALL streams from the first input file to output
@example
ffmpeg -i INPUT -map 0 output
@end example

736
For example, if you have two audio streams in the first input file,
737 738
these streams are identified by "0:0" and "0:1". You can use
@code{-map} to select which streams to place in an output file. For
739 740
example:
@example
741
ffmpeg -i INPUT -map 0:1 out.wav
742
@end example
743
will map the input stream in @file{INPUT} identified by "0:1" to
744 745 746
the (single) output stream in @file{out.wav}.

For example, to select the stream with index 2 from input file
747 748
@file{a.mov} (specified by the identifier "0:2"), and stream with
index 6 from input @file{b.mov} (specified by the identifier "1:6"),
749 750
and copy them to the output file @file{out.mov}:
@example
751
ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
752 753
@end example

754 755 756 757
To select all video and the third audio stream from an input file:
@example
ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
@end example
758

759 760 761 762
To map all the streams except the second audio, use negative mappings
@example
ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
@end example
763

764 765
Note that using this option disables the default mappings for this output file.

766 767
@item -map_channel [@var{input_file_id}.@var{stream_specifier}.@var{channel_id}|-1][:@var{output_file_id}.@var{stream_specifier}]
Map an audio channel from a given input to an output. If
768
@var{output_file_id}.@var{stream_specifier} is not set, the audio channel will
769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789
be mapped on all the audio streams.

Using "-1" instead of
@var{input_file_id}.@var{stream_specifier}.@var{channel_id} will map a muted
channel.

For example, assuming @var{INPUT} is a stereo audio file, you can switch the
two audio channels with the following command:
@example
ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
@end example

If you want to mute the first channel and keep the second:
@example
ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
@end example

The order of the "-map_channel" option specifies the order of the channels in
the output stream. The output channel layout is guessed from the number of
channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac"
in combination of "-map_channel" makes the channel gain levels to be updated if
790 791
input and output channel layouts don't match (for instance two "-map_channel"
options and "-ac 6").
792

793 794 795
You can also extract each channel of an input to specific outputs; the following
command extracts two channels of the @var{INPUT} audio stream (file 0, stream 0)
to the respective @var{OUTPUT_CH0} and @var{OUTPUT_CH1} outputs:
796 797 798 799
@example
ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
@end example

800 801
The following example splits the channels of a stereo input into two separate
streams, which are put into the same output file:
802 803 804 805
@example
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
@end example

806 807 808 809 810
Note that currently each output stream can only contain channels from a single
input stream; you can't for example use "-map_channel" to pick multiple input
audio channels contained in different streams (from the same or different files)
and merge them into a single output stream. It is therefore not currently
possible, for example, to turn two separate mono streams into a single stereo
811
stream. However splitting a stereo stream into two single channel mono streams
812
is possible.
813

814 815 816
If you need this feature, a possible workaround is to use the @emph{amerge}
filter. For example, if you need to merge a media (here @file{input.mkv}) with 2
mono audio streams into one single stereo channel audio stream (and keep the
817
video stream), you can use the following command:
818
@example
819
ffmpeg -i input.mkv -filter_complex "[0:1] [0:2] amerge" -c:a pcm_s16le -c:v copy output.mkv
820 821
@end example

Michael Niedermayer's avatar
Michael Niedermayer committed
822
@item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
823 824
Set metadata information of the next output file from @var{infile}. Note that
those are file indices (zero-based), not filenames.
Michael Niedermayer's avatar
Michael Niedermayer committed
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
A metadata specifier can have the following forms:
@table @option
@item @var{g}
global metadata, i.e. metadata that applies to the whole file

@item @var{s}[:@var{stream_spec}]
per-stream metadata. @var{stream_spec} is a stream specifier as described
in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
matching stream is copied from. In an output metadata specifier, all matching
streams are copied to.

@item @var{c}:@var{chapter_index}
per-chapter metadata. @var{chapter_index} is the zero-based chapter index.

@item @var{p}:@var{program_index}
per-program metadata. @var{program_index} is the zero-based program index.
@end table
If metadata specifier is omitted, it defaults to global.
844

845
By default, global metadata is copied from the first input file,
846 847 848 849
per-stream and per-chapter metadata is copied along with streams/chapters. These
default mappings are disabled by creating any mapping of the relevant type. A negative
file index can be used to create a dummy mapping that just disables automatic copying.

850 851 852
For example to copy metadata from the first stream of the input file to global metadata
of the output file:
@example
853
ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
854
@end example
Michael Niedermayer's avatar
Michael Niedermayer committed
855 856 857 858 859 860 861 862

To do the reverse, i.e. copy global metadata to all audio streams:
@example
ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv
@end example
Note that simple @code{0} would work as well in this example, since global
metadata is assumed by default.

863 864 865 866 867
@item -map_chapters @var{input_file_index} (@emph{output})
Copy chapters from input file with index @var{input_file_index} to the next
output file. If no chapter mapping is specified, then chapters are copied from
the first input file with at least one chapter. Use a negative file index to
disable any chapter copying.
868

869
@item -benchmark (@emph{global})
870 871 872 873
Show benchmarking information at the end of an encode.
Shows CPU time used and maximum memory consumption.
Maximum memory consumption is not supported on all systems,
it will usually display as 0 if not supported.
874 875 876
@item -benchmark_all (@emph{global})
Show benchmarking information during the encode.
Shows CPU time used in various steps (audio/video encode/decode).
877 878
@item -timelimit @var{duration} (@emph{global})
Exit after ffmpeg has been running for @var{duration} seconds.
879
@item -dump (@emph{global})
880
Dump each input packet to stderr.
881
@item -hex (@emph{global})
882
When dumping packets, also dump the payload.
883
@item -re (@emph{input})
Diego Biurrun's avatar
Diego Biurrun committed
884
Read input at native frame rate. Mainly used to simulate a grab device.
885 886 887
or live input stream (e.g. when reading from a file). Should not be used
with actual grab devices or live input streams (where it can cause packet
loss).
888 889
By default @command{ffmpeg} attempts to read the input(s) as fast as possible.
This option will slow down the reading of the input(s) to the native frame rate
890
of the input(s). It is useful for real-time output (e.g. live streaming).
891
@item -loop_input
Diego Biurrun's avatar
Diego Biurrun committed
892 893
Loop over the input stream. Currently it works only for image
streams. This option is used for automatic FFserver testing.
Carl Eugen Hoyos's avatar
Carl Eugen Hoyos committed
894
This option is deprecated, use -loop 1.
895
@item -loop_output @var{number_of_times}
Diego Biurrun's avatar
Diego Biurrun committed
896
Repeatedly loop output for formats that support looping such as animated GIF
Diego Biurrun's avatar
Diego Biurrun committed
897
(0 will loop the output infinitely).
898
This option is deprecated, use -loop.
899
@item -vsync @var{parameter}
900
Video sync method.
Reimar Döffinger's avatar
Reimar Döffinger committed
901 902
For compatibility reasons old values can be specified as numbers.
Newly added values will have to be specified as strings always.
903 904

@table @option
905
@item 0, passthrough
906
Each frame is passed with its timestamp from the demuxer to the muxer.
907
@item 1, cfr
908
Frames will be duplicated and dropped to achieve exactly the requested
909
constant frame rate.
910
@item 2, vfr
911 912
Frames are passed through with their timestamp or dropped so as to
prevent 2 frames from having the same timestamp.
Reimar Döffinger's avatar
Reimar Döffinger committed
913 914 915
@item drop
As passthrough but destroys all timestamps, making the muxer generate
fresh timestamps based on frame-rate.
916
@item -1, auto
917 918 919 920
Chooses between 1 and 2 depending on muxer capabilities. This is the
default method.
@end table

921 922 923 924
Note that the timestamps may be further modified by the muxer, after this.
For example, in the case that the format option @option{avoid_negative_ts}
is enabled.

925 926 927 928
With -map you can select from which stream the timestamps should be
taken. You can leave either video or audio unchanged and sync the
remaining stream(s) to the unchanged one.

929
@item -async @var{samples_per_second}
930
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
931 932 933
the parameter is the maximum samples per second by which the audio is changed.
-async 1 is a special case where only the start of the audio stream is corrected
without any later correction.
934 935 936 937 938

Note that the timestamps may be further modified by the muxer, after this.
For example, in the case that the format option @option{avoid_negative_ts}
is enabled.

939
This option has been deprecated. Use the @code{aresample} audio filter instead.
940

941
@item -copyts
942 943 944 945 946
Do not process input timestamps, but keep their values without trying
to sanitize them. In particular, do not remove the initial start time
offset value.

Note that, depending on the @option{vsync} option or on specific muxer
947 948
processing (e.g. in case the format option @option{avoid_negative_ts}
is enabled) the output timestamps may mismatch with the input
949 950
timestamps even when this option is selected.

951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974
@item -copytb @var{mode}
Specify how to set the encoder timebase when stream copying.  @var{mode} is an
integer numeric value, and can assume one of the following values:

@table @option
@item 1
Use the demuxer timebase.

The time base is copied to the output encoder from the corresponding input
demuxer. This is sometimes required to avoid non monotonically increasing
timestamps when copying video streams with variable frame rate.

@item 0
Use the decoder timebase.

The time base is copied to the output encoder from the corresponding input
decoder.

@item -1
Try to make the choice automatically, in order to generate a sane output.
@end table

Default value is -1.

975
@item -shortest (@emph{output})
976 977 978
Finish encoding when the shortest input stream ends.
@item -dts_delta_threshold
Timestamp discontinuity delta threshold.
979
@item -muxdelay @var{seconds} (@emph{input})
980
Set the maximum demux-decode delay.
981
@item -muxpreload @var{seconds} (@emph{input})
982
Set the initial demux-decode delay.
983
@item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
984 985 986 987
Assign a new stream-id value to an output stream. This option should be
specified prior to the output filename to which it applies.
For the situation where multiple output files exist, a streamid
may be reassigned to a different value.
988 989 990 991 992 993

For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
an output mpegts file:
@example
ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
@end example
994 995

@item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
996
Set bitstream filters for matching streams. @var{bitstream_filters} is
997 998 999
a comma-separated list of bitstream filters. Use the @code{-bsfs} option
to get the list of bitstream filters.
@example
1000
ffmpeg -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
1001 1002
@end example
@example
1003
ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
1004 1005
@end example

1006
@item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{per-stream})
1007
Force a tag/fourcc for matching streams.
1008 1009 1010 1011 1012 1013 1014

@item -timecode @var{hh}:@var{mm}:@var{ss}SEP@var{ff}
Specify Timecode for writing. @var{SEP} is ':' for non drop timecode and ';'
(or '.') for drop.
@example
ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
@end example
1015

1016
@anchor{filter_complex_option}
1017
@item -filter_complex @var{filtergraph} (@emph{global})
1018
Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
1019 1020
outputs. For simple graphs -- those with one input and one output of the same
type -- see the @option{-filter} options. @var{filtergraph} is a description of
1021
the filtergraph, as described in the ``Filtergraph syntax'' section of the
1022
ffmpeg-filters manual.
1023 1024 1025 1026 1027 1028 1029 1030 1031 1032

Input link labels must refer to input streams using the
@code{[file_index:stream_specifier]} syntax (i.e. the same as @option{-map}
uses). If @var{stream_specifier} matches multiple streams, the first one will be
used. An unlabeled input will be connected to the first unused input stream of
the matching type.

Output link labels are referred to with @option{-map}. Unlabeled outputs are
added to the first output file.

1033 1034 1035
Note that with this option it is possible to use only lavfi sources without
normal input files.

1036 1037
For example, to overlay an image over video
@example
1038
ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
1039 1040 1041 1042 1043 1044 1045 1046 1047 1048
'[out]' out.mkv
@end example
Here @code{[0:v]} refers to the first video stream in the first input file,
which is linked to the first (main) input of the overlay filter. Similarly the
first video stream in the second input is linked to the second (overlay) input
of overlay.

Assuming there is only one video stream in each input file, we can omit input
labels, so the above is equivalent to
@example
1049
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
1050 1051 1052 1053 1054 1055
'[out]' out.mkv
@end example

Furthermore we can omit the output label and the single output from the filter
graph will be added to the output file automatically, so we can simply write
@example
1056
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
1057
@end example
1058 1059 1060

To generate 5 seconds of pure red video using lavfi @code{color} source:
@example
1061
ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
1062
@end example
1063 1064

@item -lavfi @var{filtergraph} (@emph{global})
1065
Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
1066 1067
outputs. Equivalent to @option{-filter_complex}.

1068 1069 1070 1071 1072
@item -filter_complex_script @var{filename} (@emph{global})
This option is similar to @option{-filter_complex}, the only difference is that
its argument is the name of the file from which a complex filtergraph
description is to be read.

1073 1074 1075 1076 1077 1078
@item -accurate_seek (@emph{input})
This option enables or disables accurate seeking in input files with the
@option{-ss} option. It is enabled by default, so seeking is accurate when
transcoding. Use @option{-noaccurate_seek} to disable it, which may be useful
e.g. when copying some streams and transcoding the others.

1079 1080 1081 1082 1083 1084 1085 1086
@item -override_ffserver (@emph{global})
Overrides the input specifications from ffserver. Using this option you can
map any input stream to ffserver and control many aspects of the encoding from
ffmpeg. Without this option ffmpeg will transmit to ffserver what is requested by
ffserver.
The option is intended for cases where features are needed that cannot be
specified to ffserver but can be to ffmpeg.

1087
@end table
Fabrice Bellard's avatar
Fabrice Bellard committed
1088

1089 1090
As a special exception, you can use a bitmap subtitle stream as input: it
will be converted into a video with the same size as the largest video in
1091
the file, or 720x576 if no video is present. Note that this is an
1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
experimental and temporary solution. It will be removed once libavfilter has
proper support for subtitles.

For example, to hardcode subtitles on top of a DVB-T recording stored in
MPEG-TS format, delaying the subtitles by 1 second:
@example
ffmpeg -i input.ts -filter_complex \
  '[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \
  -sn -map '#0x2dc' output.mkv
@end example
(0x2d0, 0x2dc and 0x2ef are the MPEG-TS PIDs of respectively the video,
audio and subtitles streams; 0:0, 0:3 and 0:7 would have worked too)

1105 1106 1107 1108 1109
@section Preset files
A preset file contains a sequence of @var{option}=@var{value} pairs,
one for each line, specifying a sequence of options which would be
awkward to specify on the command line. Lines starting with the hash
('#') character are ignored and are used to provide comments. Check
1110
the @file{presets} directory in the FFmpeg source tree for examples.
1111

1112 1113 1114 1115 1116
Preset files are specified with the @code{vpre}, @code{apre},
@code{spre}, and @code{fpre} options. The @code{fpre} option takes the
filename of the preset instead of a preset name as input and can be
used for any kind of codec. For the @code{vpre}, @code{apre}, and
@code{spre} options, the options specified in a preset file are
1117 1118
applied to the currently selected codec of the same type as the preset
option.
1119

1120 1121 1122
The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
preset options identifies the preset file to use according to the
following rules:
1123 1124

First ffmpeg searches for a file named @var{arg}.ffpreset in the
1125 1126
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
Gianluigi Tiesi's avatar
Gianluigi Tiesi committed
1127
or in a @file{ffpresets} folder along the executable on win32,
1128 1129
in that order. For example, if the argument is @code{libvpx-1080p}, it will
search for the file @file{libvpx-1080p.ffpreset}.
1130 1131 1132 1133 1134

If no such file is found, then ffmpeg will search for a file named
@var{codec_name}-@var{arg}.ffpreset in the above-mentioned
directories, where @var{codec_name} is the name of the codec to which
the preset file options will be applied. For example, if you select
1135 1136
the video codec with @code{-vcodec libvpx} and use @code{-vpre 1080p},
then it will search for the file @file{libvpx-1080p.ffpreset}.
1137
@c man end OPTIONS
1138

1139
@chapter Tips
1140
@c man begin TIPS
1141 1142

@itemize
1143
@item
1144
For streaming at very low bitrates, use a low frame rate
Diego Biurrun's avatar
Diego Biurrun committed
1145
and a small GOP size. This is especially true for RealVideo where
1146 1147
the Linux player does not seem to be very fast, so it can miss
frames. An example is:
1148 1149

@example
1150
ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm
1151 1152
@end example

1153 1154
@item
The parameter 'q' which is displayed while encoding is the current
Diego Biurrun's avatar
Diego Biurrun committed
1155 1156
quantizer. The value 1 indicates that a very good quality could
be achieved. The value 31 indicates the worst quality. If q=31 appears
1157
too often, it means that the encoder cannot compress enough to meet
Diego Biurrun's avatar
Diego Biurrun committed
1158
your bitrate. You must either increase the bitrate, decrease the
1159
frame rate or decrease the frame size.
1160

1161 1162
@item
If your computer is not fast enough, you can speed up the
1163
compression at the expense of the compression ratio. You can use
1164
'-me zero' to speed up motion estimation, and '-g 0' to disable
Diego Biurrun's avatar
Diego Biurrun committed
1165
motion estimation completely (you have only I-frames, which means it
1166
is about as good as JPEG compression).
1167

1168 1169
@item
To have very low audio bitrates, reduce the sampling frequency
1170
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
1171

1172 1173
@item
To have a constant quality (but a variable bitrate), use the option
1174 1175
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
quality).
1176 1177

@end itemize
1178
@c man end TIPS
1179

1180 1181 1182
@chapter Examples
@c man begin EXAMPLES

Michael Niedermayer's avatar
Michael Niedermayer committed
1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197
@section Preset files

A preset file contains a sequence of @var{option=value} pairs, one for
each line, specifying a sequence of options which can be specified also on
the command line. Lines starting with the hash ('#') character are ignored and
are used to provide comments. Empty lines are also ignored. Check the
@file{presets} directory in the FFmpeg source tree for examples.

Preset files are specified with the @code{pre} option, this option takes a
preset name as input.  FFmpeg searches for a file named @var{preset_name}.avpreset in
the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
the data directory defined at configuration time (usually @file{$PREFIX/share/ffmpeg})
in that order.  For example, if the argument is @code{libx264-max}, it will
search for the file @file{libx264-max.avpreset}.

1198 1199
@section Video and Audio grabbing

1200 1201
If you specify the input format and device then ffmpeg can grab video
and audio directly.
1202 1203 1204

@example
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
1205 1206 1207 1208 1209
@end example

Or with an ALSA audio source (mono input, card id 1) instead of OSS:
@example
ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
1210 1211 1212
@end example

Note that you must activate the right video source and channel before
1213 1214
launching ffmpeg with any TV viewer such as
@uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
1215 1216 1217 1218 1219
have to set the audio recording levels correctly with a
standard mixer.

@section X11 grabbing

1220
Grab the X11 display with ffmpeg via
1221 1222

@example
1223
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0 /tmp/out.mpg
1224 1225 1226 1227 1228 1229
@end example

0.0 is display.screen number of your X11 server, same as
the DISPLAY environment variable.

@example
1230
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0+10,20 /tmp/out.mpg
1231 1232
@end example

1233 1234
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
1235 1236 1237

@section Video and Audio file format conversion

1238
Any supported file format and protocol can serve as input to ffmpeg:
1239 1240

Examples:
1241 1242 1243
@itemize
@item
You can use YUV files as input:
1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257

@example
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
@end example

It will use the files:
@example
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
@end example

The Y files use twice the resolution of the U and V files. They are
raw files, without header. They can be generated by all decent video
decoders. You must specify the size of the image with the @option{-s} option
1258
if ffmpeg cannot guess it.
1259

1260 1261
@item
You can input from a raw YUV420P file:
1262 1263 1264 1265 1266 1267 1268 1269 1270

@example
ffmpeg -i /tmp/test.yuv /tmp/out.avi
@end example

test.yuv is a file containing raw YUV planar data. Each frame is composed
of the Y plane followed by the U and V planes at half vertical and
horizontal resolution.

1271 1272
@item
You can output to a raw YUV420P file:
1273 1274 1275 1276 1277

@example
ffmpeg -i mydivx.avi hugefile.yuv
@end example

1278 1279
@item
You can set several input files and output files:
1280 1281 1282 1283 1284 1285 1286 1287

@example
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
@end example

Converts the audio file a.wav and the raw YUV video file a.yuv
to MPEG file a.mpg.

1288 1289
@item
You can also do audio and video conversions at the same time:
1290 1291 1292 1293 1294 1295 1296

@example
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
@end example

Converts a.wav to MPEG audio at 22050 Hz sample rate.

1297 1298
@item
You can encode to several formats at the same time and define a
1299 1300 1301
mapping from input stream to output streams:

@example
1302
ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
1303 1304 1305 1306 1307 1308
@end example

Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
file:index' specifies which input stream is used for each output
stream, in the order of the definition of output streams.

1309 1310
@item
You can transcode decrypted VOBs:
1311 1312

@example
1313
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
1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326
@end example

This is a typical DVD ripping example; the input is a VOB file, the
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
input video. Furthermore, the audio stream is MP3-encoded so you need
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
The mapping is particularly useful for DVD transcoding
to get the desired audio language.

NOTE: To see the supported input formats, use @code{ffmpeg -formats}.

1327 1328
@item
You can extract images from a video, or create a video from many images:
1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350

For extracting images from a video:
@example
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
@end example

This will extract one video frame per second from the video and will
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
etc. Images will be rescaled to fit the new WxH values.

If you want to extract just a limited number of frames, you can use the
above command in combination with the -vframes or -t option, or in
combination with -ss to start extracting from a certain point in time.

For creating a video from many images:
@example
ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
@end example

The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
composed of three digits padded with zeroes to express the sequence
number. It is the same syntax supported by the C printf function, but
1351 1352
only formats accepting a normal integer are suitable.

1353 1354 1355 1356 1357 1358 1359 1360 1361
When importing an image sequence, -i also supports expanding
shell-like wildcard patterns (globbing) internally, by selecting the
image2-specific @code{-pattern_type glob} option.

For example, for creating a video from filenames matching the glob pattern
@code{foo-*.jpeg}:
@example
ffmpeg -f image2 -pattern_type glob -i 'foo-*.jpeg' -r 12 -s WxH foo.avi
@end example
1362

1363 1364
@item
You can put many streams of the same type in the output:
1365 1366

@example
1367
ffmpeg -i test1.avi -i test2.avi -map 0:3 -map 0:2 -map 0:1 -map 0:0 -c copy test12.nut
1368 1369
@end example

1370 1371
The resulting output file @file{test12.avi} will contain first four streams from
the input file in reverse order.
1372

1373 1374 1375
@item
To force CBR video output:
@example
1376
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
1377 1378 1379 1380 1381 1382
@end example

@item
The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
but you may use the QP2LAMBDA constant to easily convert from 'q' units:
@example
1383
ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
1384 1385
@end example

1386
@end itemize
1387 1388
@c man end EXAMPLES

1389
@include config.texi
1390
@ifset config-all
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413
@ifset config-avutil
@include utils.texi
@end ifset
@ifset config-avcodec
@include codecs.texi
@include bitstream_filters.texi
@end ifset
@ifset config-avformat
@include formats.texi
@include protocols.texi
@end ifset
@ifset config-avdevice
@include devices.texi
@end ifset
@ifset config-swresample
@include resampler.texi
@end ifset
@ifset config-swscale
@include scaler.texi
@end ifset
@ifset config-avfilter
@include filters.texi
@end ifset
1414 1415
@end ifset

1416 1417 1418
@chapter See Also

@ifhtml
1419 1420 1421 1422 1423 1424
@ifset config-all
@url{ffmpeg.html,ffmpeg}
@end ifset
@ifset config-not-all
@url{ffmpeg-all.html,ffmpeg-all},
@end ifset
1425 1426 1427 1428 1429
@url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe}, @url{ffserver.html,ffserver},
@url{ffmpeg-utils.html,ffmpeg-utils},
@url{ffmpeg-scaler.html,ffmpeg-scaler},
@url{ffmpeg-resampler.html,ffmpeg-resampler},
@url{ffmpeg-codecs.html,ffmpeg-codecs},
1430
@url{ffmpeg-bitstream-filters.html,ffmpeg-bitstream-filters},
1431 1432 1433 1434 1435 1436 1437
@url{ffmpeg-formats.html,ffmpeg-formats},
@url{ffmpeg-devices.html,ffmpeg-devices},
@url{ffmpeg-protocols.html,ffmpeg-protocols},
@url{ffmpeg-filters.html,ffmpeg-filters}
@end ifhtml

@ifnothtml
1438 1439 1440 1441 1442 1443
@ifset config-all
ffmpeg(1),
@end ifset
@ifset config-not-all
ffmpeg-all(1),
@end ifset
1444 1445 1446 1447 1448 1449
ffplay(1), ffprobe(1), ffserver(1),
ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1),
ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1),
ffmpeg-devices(1), ffmpeg-protocols(1), ffmpeg-filters(1)
@end ifnothtml

1450 1451
@include authors.texi

1452 1453 1454
@ignore

@setfilename ffmpeg
1455
@settitle ffmpeg video converter
1456 1457 1458

@end ignore

1459
@bye