Statistics
| Branch: | Revision:

ffmpeg / doc / ffmpeg.texi @ 4bc28232

History | View | Annotate | Download (30.8 KB)

1
\input texinfo @c -*- texinfo -*-
2

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

    
8
@top
9

    
10
@contents
11

    
12
@chapter Synopsis
13

    
14
The generic syntax is:
15

    
16
@example
17
@c man begin SYNOPSIS
18
ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
19
@c man end
20
@end example
21

    
22
@chapter Description
23
@c man begin DESCRIPTION
24

    
25
ffmpeg is a very fast video and audio converter that can also grab from
26
a live audio/video source. It can also convert between arbitrary sample
27
rates and resize video on the fly with a high quality polyphase filter.
28

    
29
The command line interface is designed to be intuitive, in the sense
30
that ffmpeg tries to figure out all parameters that can possibly be
31
derived automatically. You usually only have to specify the target
32
bitrate you want.
33

    
34
As a general rule, options are applied to the next specified
35
file. Therefore, order is important, and you can have the same
36
option on the command line multiple times. Each occurrence is
37
then applied to the next input or output file.
38

    
39
@itemize
40
@item
41
To set the video bitrate of the output file to 64kbit/s:
42
@example
43
ffmpeg -i input.avi -b 64k output.avi
44
@end example
45

    
46
@item
47
To force the frame rate of the output file to 24 fps:
48
@example
49
ffmpeg -i input.avi -r 24 output.avi
50
@end example
51

    
52
@item
53
To force the frame rate of the input file (valid for raw formats only)
54
to 1 fps and the frame rate of the output file to 24 fps:
55
@example
56
ffmpeg -r 1 -i input.m2v -r 24 output.avi
57
@end example
58
@end itemize
59

    
60
The format option may be needed for raw input files.
61

    
62
By default ffmpeg tries to convert as losslessly as possible: It
63
uses the same audio and video parameters for the outputs as the one
64
specified for the inputs.
65

    
66
@c man end DESCRIPTION
67

    
68
@chapter Options
69
@c man begin OPTIONS
70

    
71
@include fftools-common-opts.texi
72

    
73
@section Main options
74

    
75
@table @option
76

    
77
@item -f @var{fmt}
78
Force format.
79

    
80
@item -i @var{filename}
81
input file name
82

    
83
@item -y
84
Overwrite output files.
85

    
86
@item -t @var{duration}
87
Restrict the transcoded/captured video sequence
88
to the duration specified in seconds.
89
@code{hh:mm:ss[.xxx]} syntax is also supported.
90

    
91
@item -fs @var{limit_size}
92
Set the file size limit.
93

    
94
@item -ss @var{position}
95
Seek to given time position in seconds.
96
@code{hh:mm:ss[.xxx]} syntax is also supported.
97

    
98
@item -itsoffset @var{offset}
99
Set the input time offset in seconds.
100
@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
101
This option affects all the input files that follow it.
102
The offset is added to the timestamps of the input files.
103
Specifying a positive offset means that the corresponding
104
streams are delayed by 'offset' seconds.
105

    
106
@item -timestamp @var{time}
107
Set the recording timestamp in the container.
108
The syntax for @var{time} is:
109
@example
110
now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
111
@end example
112
If the value is "now" it takes the current time.
113
Time is local time unless 'Z' or 'z' is appended, in which case it is
114
interpreted as UTC.
115
If the year-month-day part is not specified it takes the current
116
year-month-day.
117

    
118
@item -metadata @var{key}=@var{value}
119
Set a metadata key/value pair.
120

    
121
For example, for setting the title in the output file:
122
@example
123
ffmpeg -i in.avi -metadata title="my title" out.flv
124
@end example
125

    
126
@item -v @var{number}
127
Set the logging verbosity level.
128

    
129
@item -target @var{type}
130
Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
131
"ntsc-svcd", ... ). All the format options (bitrate, codecs,
132
buffer sizes) are then set automatically. You can just type:
133

    
134
@example
135
ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
136
@end example
137

    
138
Nevertheless you can specify additional options as long as you know
139
they do not conflict with the standard, as in:
140

    
141
@example
142
ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
143
@end example
144

    
145
@item -dframes @var{number}
146
Set the number of data frames to record.
147

    
148
@item -scodec @var{codec}
149
Force subtitle codec ('copy' to copy stream).
150

    
151
@item -newsubtitle
152
Add a new subtitle stream to the current output stream.
153

    
154
@item -slang @var{code}
155
Set the ISO 639 language code (3 letters) of the current subtitle stream.
156

    
157
@end table
158

    
159
@section Video Options
160

    
161
@table @option
162
@item -b @var{bitrate}
163
Set the video bitrate in bit/s (default = 200 kb/s).
164
@item -vframes @var{number}
165
Set the number of video frames to record.
166
@item -r @var{fps}
167
Set frame rate (Hz value, fraction or abbreviation), (default = 25).
168
@item -s @var{size}
169
Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
170
The following abbreviations are recognized:
171
@table @samp
172
@item sqcif
173
128x96
174
@item qcif
175
176x144
176
@item cif
177
352x288
178
@item 4cif
179
704x576
180
@item 16cif
181
1408x1152
182
@item qqvga
183
160x120
184
@item qvga
185
320x240
186
@item vga
187
640x480
188
@item svga
189
800x600
190
@item xga
191
1024x768
192
@item uxga
193
1600x1200
194
@item qxga
195
2048x1536
196
@item sxga
197
1280x1024
198
@item qsxga
199
2560x2048
200
@item hsxga
201
5120x4096
202
@item wvga
203
852x480
204
@item wxga
205
1366x768
206
@item wsxga
207
1600x1024
208
@item wuxga
209
1920x1200
210
@item woxga
211
2560x1600
212
@item wqsxga
213
3200x2048
214
@item wquxga
215
3840x2400
216
@item whsxga
217
6400x4096
218
@item whuxga
219
7680x4800
220
@item cga
221
320x200
222
@item ega
223
640x350
224
@item hd480
225
852x480
226
@item hd720
227
1280x720
228
@item hd1080
229
1920x1080
230
@end table
231

    
232
@item -aspect @var{aspect}
233
Set the video display aspect ratio specified by @var{aspect}.
234

    
235
@var{aspect} can be a floating point number string, or a string of the
236
form @var{num}:@var{den}, where @var{num} and @var{den} are the
237
numerator and denominator of the aspect ratio. For example "4:3",
238
"16:9", "1.3333", and "1.7777" are valid argument values.
239

    
240
@item -croptop @var{size}
241
@item -cropbottom @var{size}
242
@item -cropleft @var{size}
243
@item -cropright @var{size}
244
All the crop options have been removed. Use -vf
245
crop=width:height:x:y instead.
246

    
247
@item -padtop @var{size}
248
@item -padbottom @var{size}
249
@item -padleft @var{size}
250
@item -padright @var{size}
251
@item -padcolor @var{hex_color}
252
All the pad options have been removed. Use -vf
253
pad=width:height:x:y:color instead.
254
@item -vn
255
Disable video recording.
256
@item -bt @var{tolerance}
257
Set video bitrate tolerance (in bits, default 4000k).
258
Has a minimum value of: (target_bitrate/target_framerate).
259
In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
260
willing to deviate from the target average bitrate value. This is
261
not related to min/max bitrate. Lowering tolerance too much has
262
an adverse effect on quality.
263
@item -maxrate @var{bitrate}
264
Set max video bitrate (in bit/s).
265
Requires -bufsize to be set.
266
@item -minrate @var{bitrate}
267
Set min video bitrate (in bit/s).
268
Most useful in setting up a CBR encode:
269
@example
270
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
271
@end example
272
It is of little use elsewise.
273
@item -bufsize @var{size}
274
Set video buffer verifier buffer size (in bits).
275
@item -vcodec @var{codec}
276
Force video codec to @var{codec}. Use the @code{copy} special value to
277
tell that the raw codec data must be copied as is.
278
@item -sameq
279
Use same quantizer as source (implies VBR).
280

    
281
@item -pass @var{n}
282
Select the pass number (1 or 2). It is used to do two-pass
283
video encoding. The statistics of the video are recorded in the first
284
pass into a log file (see also the option -passlogfile),
285
and in the second pass that log file is used to generate the video
286
at the exact requested bitrate.
287
On pass 1, you may just deactivate audio and set output to null,
288
examples for Windows and Unix:
289
@example
290
ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
291
ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
292
@end example
293

    
294
@item -passlogfile @var{prefix}
295
Set two-pass log file name prefix to @var{prefix}, the default file name
296
prefix is ``ffmpeg2pass''. The complete file name will be
297
@file{PREFIX-N.log}, where N is a number specific to the output
298
stream.
299

    
300
@item -newvideo
301
Add a new video stream to the current output stream.
302

    
303
@item -vlang @var{code}
304
Set the ISO 639 language code (3 letters) of the current video stream.
305

    
306
@item -vf @var{filter_graph}
307
@var{filter_graph} is a description of the filter graph to apply to
308
the input video.
309
Use the option "-filters" to show all the available filters (including
310
also sources and sinks).
311

    
312
@end table
313

    
314
@section Advanced Video Options
315

    
316
@table @option
317
@item -pix_fmt @var{format}
318
Set pixel format. Use 'list' as parameter to show all the supported
319
pixel formats.
320
@item -sws_flags @var{flags}
321
Set SwScaler flags.
322
@item -g @var{gop_size}
323
Set the group of pictures size.
324
@item -intra
325
Use only intra frames.
326
@item -vdt @var{n}
327
Discard threshold.
328
@item -qscale @var{q}
329
Use fixed video quantizer scale (VBR).
330
@item -qmin @var{q}
331
minimum video quantizer scale (VBR)
332
@item -qmax @var{q}
333
maximum video quantizer scale (VBR)
334
@item -qdiff @var{q}
335
maximum difference between the quantizer scales (VBR)
336
@item -qblur @var{blur}
337
video quantizer scale blur (VBR) (range 0.0 - 1.0)
338
@item -qcomp @var{compression}
339
video quantizer scale compression (VBR) (default 0.5).
340
Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
341

    
342
@item -lmin @var{lambda}
343
minimum video lagrange factor (VBR)
344
@item -lmax @var{lambda}
345
max video lagrange factor (VBR)
346
@item -mblmin @var{lambda}
347
minimum macroblock quantizer scale (VBR)
348
@item -mblmax @var{lambda}
349
maximum macroblock quantizer scale (VBR)
350

    
351
These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
352
but you may use the QP2LAMBDA constant to easily convert from 'q' units:
353
@example
354
ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
355
@end example
356

    
357
@item -rc_init_cplx @var{complexity}
358
initial complexity for single pass encoding
359
@item -b_qfactor @var{factor}
360
qp factor between P- and B-frames
361
@item -i_qfactor @var{factor}
362
qp factor between P- and I-frames
363
@item -b_qoffset @var{offset}
364
qp offset between P- and B-frames
365
@item -i_qoffset @var{offset}
366
qp offset between P- and I-frames
367
@item -rc_eq @var{equation}
368
Set rate control equation (see section "Expression Evaluation")
369
(default = @code{tex^qComp}).
370

    
371
When computing the rate control equation expression, besides the
372
standard functions defined in the section "Expression Evaluation", the
373
following functions are available:
374
@table @var
375
@item bits2qp(bits)
376
@item qp2bits(qp)
377
@end table
378

    
379
and the following constants are available:
380
@table @var
381
@item iTex
382
@item pTex
383
@item tex
384
@item mv
385
@item fCode
386
@item iCount
387
@item mcVar
388
@item var
389
@item isI
390
@item isP
391
@item isB
392
@item avgQP
393
@item qComp
394
@item avgIITex
395
@item avgPITex
396
@item avgPPTex
397
@item avgBPTex
398
@item avgTex
399
@end table
400

    
401
@item -rc_override @var{override}
402
rate control override for specific intervals
403
@item -me_method @var{method}
404
Set motion estimation method to @var{method}.
405
Available methods are (from lowest to best quality):
406
@table @samp
407
@item zero
408
Try just the (0, 0) vector.
409
@item phods
410
@item log
411
@item x1
412
@item hex
413
@item umh
414
@item epzs
415
(default method)
416
@item full
417
exhaustive search (slow and marginally better than epzs)
418
@end table
419

    
420
@item -dct_algo @var{algo}
421
Set DCT algorithm to @var{algo}. Available values are:
422
@table @samp
423
@item 0
424
FF_DCT_AUTO (default)
425
@item 1
426
FF_DCT_FASTINT
427
@item 2
428
FF_DCT_INT
429
@item 3
430
FF_DCT_MMX
431
@item 4
432
FF_DCT_MLIB
433
@item 5
434
FF_DCT_ALTIVEC
435
@end table
436

    
437
@item -idct_algo @var{algo}
438
Set IDCT algorithm to @var{algo}. Available values are:
439
@table @samp
440
@item 0
441
FF_IDCT_AUTO (default)
442
@item 1
443
FF_IDCT_INT
444
@item 2
445
FF_IDCT_SIMPLE
446
@item 3
447
FF_IDCT_SIMPLEMMX
448
@item 4
449
FF_IDCT_LIBMPEG2MMX
450
@item 5
451
FF_IDCT_PS2
452
@item 6
453
FF_IDCT_MLIB
454
@item 7
455
FF_IDCT_ARM
456
@item 8
457
FF_IDCT_ALTIVEC
458
@item 9
459
FF_IDCT_SH4
460
@item 10
461
FF_IDCT_SIMPLEARM
462
@end table
463

    
464
@item -er @var{n}
465
Set error resilience to @var{n}.
466
@table @samp
467
@item 1
468
FF_ER_CAREFUL (default)
469
@item 2
470
FF_ER_COMPLIANT
471
@item 3
472
FF_ER_AGGRESSIVE
473
@item 4
474
FF_ER_VERY_AGGRESSIVE
475
@end table
476

    
477
@item -ec @var{bit_mask}
478
Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
479
the following values:
480
@table @samp
481
@item 1
482
FF_EC_GUESS_MVS (default = enabled)
483
@item 2
484
FF_EC_DEBLOCK (default = enabled)
485
@end table
486

    
487
@item -bf @var{frames}
488
Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
489
@item -mbd @var{mode}
490
macroblock decision
491
@table @samp
492
@item 0
493
FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in ffmpeg).
494
@item 1
495
FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
496
@item 2
497
FF_MB_DECISION_RD: rate distortion
498
@end table
499

    
500
@item -4mv
501
Use four motion vector by macroblock (MPEG-4 only).
502
@item -part
503
Use data partitioning (MPEG-4 only).
504
@item -bug @var{param}
505
Work around encoder bugs that are not auto-detected.
506
@item -strict @var{strictness}
507
How strictly to follow the standards.
508
@item -aic
509
Enable Advanced intra coding (h263+).
510
@item -umv
511
Enable Unlimited Motion Vector (h263+)
512

    
513
@item -deinterlace
514
Deinterlace pictures.
515
@item -ilme
516
Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
517
Use this option if your input file is interlaced and you want
518
to keep the interlaced format for minimum losses.
519
The alternative is to deinterlace the input stream with
520
@option{-deinterlace}, but deinterlacing introduces losses.
521
@item -psnr
522
Calculate PSNR of compressed frames.
523
@item -vstats
524
Dump video coding statistics to @file{vstats_HHMMSS.log}.
525
@item -vstats_file @var{file}
526
Dump video coding statistics to @var{file}.
527
@item -top @var{n}
528
top=1/bottom=0/auto=-1 field first
529
@item -dc @var{precision}
530
Intra_dc_precision.
531
@item -vtag @var{fourcc/tag}
532
Force video tag/fourcc.
533
@item -qphist
534
Show QP histogram.
535
@item -vbsf @var{bitstream_filter}
536
Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
537
@example
538
ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
539
@end example
540
@item -force_key_frames @var{time}[,@var{time}...]
541
Force key frames at the specified timestamps, more precisely at the first
542
frames after each specified time.
543
This option can be useful to ensure that a seek point is present at a
544
chapter mark or any other designated place in the output file.
545
The timestamps must be specified in ascending order.
546
@end table
547

    
548
@section Audio Options
549

    
550
@table @option
551
@item -aframes @var{number}
552
Set the number of audio frames to record.
553
@item -ar @var{freq}
554
Set the audio sampling frequency. For input streams it is set by
555
default to 44100 Hz, for output streams it is set by default to the
556
frequency of the input stream. If the input file has audio streams
557
with different frequencies, the behaviour is undefined.
558
@item -ab @var{bitrate}
559
Set the audio bitrate in bit/s (default = 64k).
560
@item -aq @var{q}
561
Set the audio quality (codec-specific, VBR).
562
@item -ac @var{channels}
563
Set the number of audio channels. For input streams it is set by
564
default to 1, for output streams it is set by default to the same
565
number of audio channels in input. If the input file has audio streams
566
with different channel count, the behaviour is undefined.
567
@item -an
568
Disable audio recording.
569
@item -acodec @var{codec}
570
Force audio codec to @var{codec}. Use the @code{copy} special value to
571
specify that the raw codec data must be copied as is.
572
@item -newaudio
573
Add a new audio track to the output file. If you want to specify parameters,
574
do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
575

    
576
Mapping will be done automatically, if the number of output streams is equal to
577
the number of input streams, else it will pick the first one that matches. You
578
can override the mapping using @code{-map} as usual.
579

    
580
Example:
581
@example
582
ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
583
@end example
584
@item -alang @var{code}
585
Set the ISO 639 language code (3 letters) of the current audio stream.
586
@end table
587

    
588
@section Advanced Audio options:
589

    
590
@table @option
591
@item -atag @var{fourcc/tag}
592
Force audio tag/fourcc.
593
@item -audio_service_type @var{type}
594
Set the type of service that the audio stream contains.
595
@table @option
596
@item ma
597
Main Audio Service (default)
598
@item ef
599
Effects
600
@item vi
601
Visually Impaired
602
@item hi
603
Hearing Impaired
604
@item di
605
Dialogue
606
@item co
607
Commentary
608
@item em
609
Emergency
610
@item vo
611
Voice Over
612
@item ka
613
Karaoke
614
@end table
615
@item -absf @var{bitstream_filter}
616
Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
617
@end table
618

    
619
@section Subtitle options:
620

    
621
@table @option
622
@item -scodec @var{codec}
623
Force subtitle codec ('copy' to copy stream).
624
@item -newsubtitle
625
Add a new subtitle stream to the current output stream.
626
@item -slang @var{code}
627
Set the ISO 639 language code (3 letters) of the current subtitle stream.
628
@item -sn
629
Disable subtitle recording.
630
@item -sbsf @var{bitstream_filter}
631
Bitstream filters available are "mov2textsub", "text2movsub".
632
@example
633
ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
634
@end example
635
@end table
636

    
637
@section Audio/Video grab options
638

    
639
@table @option
640
@item -vc @var{channel}
641
Set video grab channel (DV1394 only).
642
@item -tvstd @var{standard}
643
Set television standard (NTSC, PAL (SECAM)).
644
@item -isync
645
Synchronize read on input.
646
@end table
647

    
648
@section Advanced options
649

    
650
@table @option
651
@item -map @var{input_file_id}.@var{input_stream_id}[:@var{sync_file_id}.@var{sync_stream_id}]
652

    
653
Designate an input stream as a source for the output file. Each input
654
stream is identified by the input file index @var{input_file_id} and
655
the input stream index @var{input_stream_id} within the input
656
file. Both indexes start at 0. If specified,
657
@var{sync_file_id}.@var{sync_stream_id} sets which input stream
658
is used as a presentation sync reference.
659

    
660
The @code{-map} options must be specified just after the output file.
661
If any @code{-map} options are used, the number of @code{-map} options
662
on the command line must match the number of streams in the output
663
file. The first @code{-map} option on the command line specifies the
664
source for output stream 0, the second @code{-map} option specifies
665
the source for output stream 1, etc.
666

    
667
For example, if you have two audio streams in the first input file,
668
these streams are identified by "0.0" and "0.1". You can use
669
@code{-map} to select which stream to place in an output file. For
670
example:
671
@example
672
ffmpeg -i INPUT out.wav -map 0.1
673
@end example
674
will map the input stream in @file{INPUT} identified by "0.1" to
675
the (single) output stream in @file{out.wav}.
676

    
677
For example, to select the stream with index 2 from input file
678
@file{a.mov} (specified by the identifier "0.2"), and stream with
679
index 6 from input @file{b.mov} (specified by the identifier "1.6"),
680
and copy them to the output file @file{out.mov}:
681
@example
682
ffmpeg -i a.mov -i b.mov -vcodec copy -acodec copy out.mov -map 0.2 -map 1.6
683
@end example
684

    
685
To add more streams to the output file, you can use the
686
@code{-newaudio}, @code{-newvideo}, @code{-newsubtitle} options.
687

    
688
@item -map_meta_data @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
689
Deprecated, use @var{-map_metadata} instead.
690

    
691
@item -map_metadata @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
692
Set metadata information of @var{outfile} from @var{infile}. Note that those
693
are file indices (zero-based), not filenames.
694
Optional @var{metadata} parameters specify, which metadata to copy - (g)lobal
695
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
696
per-(p)rogram. All metadata specifiers other than global must be followed by the
697
stream/chapter/program number. If metadata specifier is omitted, it defaults to
698
global.
699

    
700
By default, global metadata is copied from the first input file to all output files,
701
per-stream and per-chapter metadata is copied along with streams/chapters. These
702
default mappings are disabled by creating any mapping of the relevant type. A negative
703
file index can be used to create a dummy mapping that just disables automatic copying.
704

    
705
For example to copy metadata from the first stream of the input file to global metadata
706
of the output file:
707
@example
708
ffmpeg -i in.ogg -map_metadata 0:0,s0 out.mp3
709
@end example
710
@item -map_chapters @var{outfile}:@var{infile}
711
Copy chapters from @var{infile} to @var{outfile}. If no chapter mapping is specified,
712
then chapters are copied from the first input file with at least one chapter to all
713
output files. Use a negative file index to disable any chapter copying.
714
@item -debug
715
Print specific debug info.
716
@item -benchmark
717
Show benchmarking information at the end of an encode.
718
Shows CPU time used and maximum memory consumption.
719
Maximum memory consumption is not supported on all systems,
720
it will usually display as 0 if not supported.
721
@item -dump
722
Dump each input packet.
723
@item -hex
724
When dumping packets, also dump the payload.
725
@item -bitexact
726
Only use bit exact algorithms (for codec testing).
727
@item -ps @var{size}
728
Set RTP payload size in bytes.
729
@item -re
730
Read input at native frame rate. Mainly used to simulate a grab device.
731
@item -loop_input
732
Loop over the input stream. Currently it works only for image
733
streams. This option is used for automatic FFserver testing.
734
@item -loop_output @var{number_of_times}
735
Repeatedly loop output for formats that support looping such as animated GIF
736
(0 will loop the output infinitely).
737
@item -threads @var{count}
738
Thread count.
739
@item -vsync @var{parameter}
740
Video sync method.
741

    
742
@table @option
743
@item 0
744
Each frame is passed with its timestamp from the demuxer to the muxer.
745
@item 1
746
Frames will be duplicated and dropped to achieve exactly the requested
747
constant framerate.
748
@item 2
749
Frames are passed through with their timestamp or dropped so as to
750
prevent 2 frames from having the same timestamp.
751
@item -1
752
Chooses between 1 and 2 depending on muxer capabilities. This is the
753
default method.
754
@end table
755

    
756
With -map you can select from which stream the timestamps should be
757
taken. You can leave either video or audio unchanged and sync the
758
remaining stream(s) to the unchanged one.
759

    
760
@item -async @var{samples_per_second}
761
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
762
the parameter is the maximum samples per second by which the audio is changed.
763
-async 1 is a special case where only the start of the audio stream is corrected
764
without any later correction.
765
@item -copyts
766
Copy timestamps from input to output.
767
@item -copytb
768
Copy input stream time base from input to output when stream copying.
769
@item -shortest
770
Finish encoding when the shortest input stream ends.
771
@item -dts_delta_threshold
772
Timestamp discontinuity delta threshold.
773
@item -muxdelay @var{seconds}
774
Set the maximum demux-decode delay.
775
@item -muxpreload @var{seconds}
776
Set the initial demux-decode delay.
777
@item -streamid @var{output-stream-index}:@var{new-value}
778
Assign a new stream-id value to an output stream. This option should be
779
specified prior to the output filename to which it applies.
780
For the situation where multiple output files exist, a streamid
781
may be reassigned to a different value.
782

    
783
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
784
an output mpegts file:
785
@example
786
ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
787
@end example
788
@end table
789

    
790
@section Preset files
791

    
792
A preset file contains a sequence of @var{option}=@var{value} pairs,
793
one for each line, specifying a sequence of options which would be
794
awkward to specify on the command line. Lines starting with the hash
795
('#') character are ignored and are used to provide comments. Check
796
the @file{ffpresets} directory in the Libav source tree for examples.
797

    
798
Preset files are specified with the @code{vpre}, @code{apre},
799
@code{spre}, and @code{fpre} options. The @code{fpre} option takes the
800
filename of the preset instead of a preset name as input and can be
801
used for any kind of codec. For the @code{vpre}, @code{apre}, and
802
@code{spre} options, the options specified in a preset file are
803
applied to the currently selected codec of the same type as the preset
804
option.
805

    
806
The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
807
preset options identifies the preset file to use according to the
808
following rules:
809

    
810
First ffmpeg searches for a file named @var{arg}.ffpreset in the
811
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
812
the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
813
in that order. For example, if the argument is @code{libx264-max}, it will
814
search for the file @file{libx264-max.ffpreset}.
815

    
816
If no such file is found, then ffmpeg will search for a file named
817
@var{codec_name}-@var{arg}.ffpreset in the above-mentioned
818
directories, where @var{codec_name} is the name of the codec to which
819
the preset file options will be applied. For example, if you select
820
the video codec with @code{-vcodec libx264} and use @code{-vpre max},
821
then it will search for the file @file{libx264-max.ffpreset}.
822
@c man end
823

    
824
@chapter Tips
825
@c man begin TIPS
826

    
827
@itemize
828
@item
829
For streaming at very low bitrate application, use a low frame rate
830
and a small GOP size. This is especially true for RealVideo where
831
the Linux player does not seem to be very fast, so it can miss
832
frames. An example is:
833

    
834
@example
835
ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
836
@end example
837

    
838
@item
839
The parameter 'q' which is displayed while encoding is the current
840
quantizer. The value 1 indicates that a very good quality could
841
be achieved. The value 31 indicates the worst quality. If q=31 appears
842
too often, it means that the encoder cannot compress enough to meet
843
your bitrate. You must either increase the bitrate, decrease the
844
frame rate or decrease the frame size.
845

    
846
@item
847
If your computer is not fast enough, you can speed up the
848
compression at the expense of the compression ratio. You can use
849
'-me zero' to speed up motion estimation, and '-intra' to disable
850
motion estimation completely (you have only I-frames, which means it
851
is about as good as JPEG compression).
852

    
853
@item
854
To have very low audio bitrates, reduce the sampling frequency
855
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
856

    
857
@item
858
To have a constant quality (but a variable bitrate), use the option
859
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
860
quality).
861

    
862
@item
863
When converting video files, you can use the '-sameq' option which
864
uses the same quality factor in the encoder as in the decoder.
865
It allows almost lossless encoding.
866

    
867
@end itemize
868
@c man end TIPS
869

    
870
@chapter Examples
871
@c man begin EXAMPLES
872

    
873
@section Video and Audio grabbing
874

    
875
If you specify the input format and device then ffmpeg can grab video
876
and audio directly.
877

    
878
@example
879
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
880
@end example
881

    
882
Note that you must activate the right video source and channel before
883
launching ffmpeg with any TV viewer such as xawtv
884
(@url{http://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
885
have to set the audio recording levels correctly with a
886
standard mixer.
887

    
888
@section X11 grabbing
889

    
890
Grab the X11 display with ffmpeg via
891

    
892
@example
893
ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
894
@end example
895

    
896
0.0 is display.screen number of your X11 server, same as
897
the DISPLAY environment variable.
898

    
899
@example
900
ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
901
@end example
902

    
903
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
904
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
905

    
906
@section Video and Audio file format conversion
907

    
908
Any supported file format and protocol can serve as input to ffmpeg:
909

    
910
Examples:
911
@itemize
912
@item
913
You can use YUV files as input:
914

    
915
@example
916
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
917
@end example
918

    
919
It will use the files:
920
@example
921
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
922
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
923
@end example
924

    
925
The Y files use twice the resolution of the U and V files. They are
926
raw files, without header. They can be generated by all decent video
927
decoders. You must specify the size of the image with the @option{-s} option
928
if ffmpeg cannot guess it.
929

    
930
@item
931
You can input from a raw YUV420P file:
932

    
933
@example
934
ffmpeg -i /tmp/test.yuv /tmp/out.avi
935
@end example
936

    
937
test.yuv is a file containing raw YUV planar data. Each frame is composed
938
of the Y plane followed by the U and V planes at half vertical and
939
horizontal resolution.
940

    
941
@item
942
You can output to a raw YUV420P file:
943

    
944
@example
945
ffmpeg -i mydivx.avi hugefile.yuv
946
@end example
947

    
948
@item
949
You can set several input files and output files:
950

    
951
@example
952
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
953
@end example
954

    
955
Converts the audio file a.wav and the raw YUV video file a.yuv
956
to MPEG file a.mpg.
957

    
958
@item
959
You can also do audio and video conversions at the same time:
960

    
961
@example
962
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
963
@end example
964

    
965
Converts a.wav to MPEG audio at 22050 Hz sample rate.
966

    
967
@item
968
You can encode to several formats at the same time and define a
969
mapping from input stream to output streams:
970

    
971
@example
972
ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
973
@end example
974

    
975
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
976
file:index' specifies which input stream is used for each output
977
stream, in the order of the definition of output streams.
978

    
979
@item
980
You can transcode decrypted VOBs:
981

    
982
@example
983
ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
984
@end example
985

    
986
This is a typical DVD ripping example; the input is a VOB file, the
987
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
988
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
989
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
990
input video. Furthermore, the audio stream is MP3-encoded so you need
991
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
992
The mapping is particularly useful for DVD transcoding
993
to get the desired audio language.
994

    
995
NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
996

    
997
@item
998
You can extract images from a video, or create a video from many images:
999

    
1000
For extracting images from a video:
1001
@example
1002
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
1003
@end example
1004

    
1005
This will extract one video frame per second from the video and will
1006
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1007
etc. Images will be rescaled to fit the new WxH values.
1008

    
1009
If you want to extract just a limited number of frames, you can use the
1010
above command in combination with the -vframes or -t option, or in
1011
combination with -ss to start extracting from a certain point in time.
1012

    
1013
For creating a video from many images:
1014
@example
1015
ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1016
@end example
1017

    
1018
The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1019
composed of three digits padded with zeroes to express the sequence
1020
number. It is the same syntax supported by the C printf function, but
1021
only formats accepting a normal integer are suitable.
1022

    
1023
@item
1024
You can put many streams of the same type in the output:
1025

    
1026
@example
1027
ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
1028
@end example
1029

    
1030
In addition to the first video and audio streams, the resulting
1031
output file @file{test12.avi} will contain the second video
1032
and the second audio stream found in the input streams list.
1033

    
1034
The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
1035
options have to be specified immediately after the name of the output
1036
file to which you want to add them.
1037

    
1038
@end itemize
1039
@c man end EXAMPLES
1040

    
1041
@include eval.texi
1042
@include encoders.texi
1043
@include demuxers.texi
1044
@include muxers.texi
1045
@include indevs.texi
1046
@include outdevs.texi
1047
@include protocols.texi
1048
@include bitstream_filters.texi
1049
@include filters.texi
1050
@include metadata.texi
1051

    
1052
@ignore
1053

    
1054
@setfilename ffmpeg
1055
@settitle ffmpeg video converter
1056

    
1057
@c man begin SEEALSO
1058
ffplay(1), ffprobe(1), ffserver(1) and the Libav HTML documentation
1059
@c man end
1060

    
1061
@c man begin AUTHORS
1062
The Libav developers
1063
@c man end
1064

    
1065
@end ignore
1066

    
1067
@bye