aboutsummaryrefslogtreecommitdiffstats
path: root/doc/ffmpeg.texi
blob: ac3d564ff6af1a82e385ed34cb111711c4c0f0eb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
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
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
\input texinfo @c -*- texinfo -*-

@settitle FFmpeg Documentation
@titlepage
@sp 7
@center @titlefont{FFmpeg Documentation}
@sp 3
@end titlepage

@chapter Synopsis

The generic syntax is:

@example
@c man begin SYNOPSIS
ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
@c man end
@end example

@chapter Description
@c man begin DESCRIPTION

FFmpeg is a very fast video and audio converter. It can also grab from
a live audio/video source.

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

FFmpeg can also convert from any sample rate to any other, and resize
video on the fly with a high quality polyphase filter.

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.

* To set the video bitrate of the output file to 64kbit/s:
@example
ffmpeg -i input.avi -b 64k output.avi
@end example

* To force the frame rate of the output file to 24 fps:
@example
ffmpeg -i input.avi -r 24 output.avi
@end example

* To force the frame rate of the input file (valid for raw formats only)
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

The format option may be needed for raw input files.

By default, FFmpeg tries to convert as losslessly as possible: It
uses the same audio and video parameters for the outputs as the one
specified for the inputs.

@c man end DESCRIPTION

@chapter Options
@c man begin OPTIONS

@include fftools-common-opts.texi

@section Main options

@table @option

@item -f @var{fmt}
Force format.

@item -i @var{filename}
input file name

@item -y
Overwrite output files.

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

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

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

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

@item -timestamp @var{time}
Set the recording timestamp in the container.
The syntax for @var{time} is:
@example
now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
@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.

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

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

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

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

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

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

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

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

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

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

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

@end table

@section Video Options

@table @option
@item -b @var{bitrate}
Set the video bitrate in bit/s (default = 200 kb/s).
@item -vframes @var{number}
Set the number of video frames to record.
@item -r @var{fps}
Set frame rate (Hz value, fraction or abbreviation), (default = 25).
@item -s @var{size}
Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
The following abbreviations are recognized:
@table @samp
@item sqcif
128x96
@item qcif
176x144
@item cif
352x288
@item 4cif
704x576
@item 16cif
1408x1152
@item qqvga
160x120
@item qvga
320x240
@item vga
640x480
@item svga
800x600
@item xga
1024x768
@item uxga
1600x1200
@item qxga
2048x1536
@item sxga
1280x1024
@item qsxga
2560x2048
@item hsxga
5120x4096
@item wvga
852x480
@item wxga
1366x768
@item wsxga
1600x1024
@item wuxga
1920x1200
@item woxga
2560x1600
@item wqsxga
3200x2048
@item wquxga
3840x2400
@item whsxga
6400x4096
@item whuxga
7680x4800
@item cga
320x200
@item ega
640x350
@item hd480
852x480
@item hd720
1280x720
@item hd1080
1920x1080
@end table

@item -aspect @var{aspect}
Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
@item -croptop @var{size}
@item -cropbottom @var{size}
@item -cropleft @var{size}
@item -cropright @var{size}
All the crop options have been removed. Use -vf
crop=width:height:x:y instead.

@item -padtop @var{size}
@item -padbottom @var{size}
@item -padleft @var{size}
@item -padright @var{size}
@item -padcolor @var{hex_color}
All the pad options have been removed. Use -vf
pad=width:height:x:y:color instead.
@item -vn
Disable video recording.
@item -bt @var{tolerance}
Set video bitrate tolerance (in bits, default 4000k).
Has a minimum value of: (target_bitrate/target_framerate).
In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
willing to deviate from the target average bitrate value. This is
not related to min/max bitrate. Lowering tolerance too much has
an adverse effect on quality.
@item -maxrate @var{bitrate}
Set max video bitrate (in bit/s).
Requires -bufsize to be set.
@item -minrate @var{bitrate}
Set min video bitrate (in bit/s).
Most useful in setting up a CBR encode:
@example
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
@end example
It is of little use elsewise.
@item -bufsize @var{size}
Set video buffer verifier buffer size (in bits).
@item -vcodec @var{codec}
Force video codec to @var{codec}. Use the @code{copy} special value to
tell that the raw codec data must be copied as is.
@item -sameq
Use same video quality as source (implies VBR).

@item -pass @var{n}
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.
On pass 1, you may just deactivate audio and set output to null,
examples for Windows and Unix:
@example
ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
@end example

@item -passlogfile @var{prefix}
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
stream.

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

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

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

@end table

@section Advanced Video Options

@table @option
@item -pix_fmt @var{format}
Set pixel format. Use 'list' as parameter to show all the supported
pixel formats.
@item -sws_flags @var{flags}
Set SwScaler flags.
@item -g @var{gop_size}
Set the group of pictures size.
@item -intra
Use only intra frames.
@item -vdt @var{n}
Discard threshold.
@item -qscale @var{q}
Use fixed video quantizer scale (VBR).
@item -qmin @var{q}
minimum video quantizer scale (VBR)
@item -qmax @var{q}
maximum video quantizer scale (VBR)
@item -qdiff @var{q}
maximum difference between the quantizer scales (VBR)
@item -qblur @var{blur}
video quantizer scale blur (VBR) (range 0.0 - 1.0)
@item -qcomp @var{compression}
video quantizer scale compression (VBR) (default 0.5).
Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0

@item -lmin @var{lambda}
minimum video lagrange factor (VBR)
@item -lmax @var{lambda}
max video lagrange factor (VBR)
@item -mblmin @var{lambda}
minimum macroblock quantizer scale (VBR)
@item -mblmax @var{lambda}
maximum macroblock quantizer scale (VBR)

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

@item -rc_init_cplx @var{complexity}
initial complexity for single pass encoding
@item -b_qfactor @var{factor}
qp factor between P- and B-frames
@item -i_qfactor @var{factor}
qp factor between P- and I-frames
@item -b_qoffset @var{offset}
qp offset between P- and B-frames
@item -i_qoffset @var{offset}
qp offset between P- and I-frames
@item -rc_eq @var{equation}
Set rate control equation (see section "Expression Evaluation")
(default = @code{tex^qComp}).

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

and the following constants are available:
@table @var
@item iTex
@item pTex
@item tex
@item mv
@item fCode
@item iCount
@item mcVar
@item var
@item isI
@item isP
@item isB
@item avgQP
@item qComp
@item avgIITex
@item avgPITex
@item avgPPTex
@item avgBPTex
@item avgTex
@end table

@item -rc_override @var{override}
rate control override for specific intervals
@item -me_method @var{method}
Set motion estimation method to @var{method}.
Available methods are (from lowest to best quality):
@table @samp
@item zero
Try just the (0, 0) vector.
@item phods
@item log
@item x1
@item hex
@item umh
@item epzs
(default method)
@item full
exhaustive search (slow and marginally better than epzs)
@end table

@item -dct_algo @var{algo}
Set DCT algorithm to @var{algo}. Available values are:
@table @samp
@item 0
FF_DCT_AUTO (default)
@item 1
FF_DCT_FASTINT
@item 2
FF_DCT_INT
@item 3
FF_DCT_MMX
@item 4
FF_DCT_MLIB
@item 5
FF_DCT_ALTIVEC
@end table

@item -idct_algo @var{algo}
Set IDCT algorithm to @var{algo}. Available values are:
@table @samp
@item 0
FF_IDCT_AUTO (default)
@item 1
FF_IDCT_INT
@item 2
FF_IDCT_SIMPLE
@item 3
FF_IDCT_SIMPLEMMX
@item 4
FF_IDCT_LIBMPEG2MMX
@item 5
FF_IDCT_PS2
@item 6
FF_IDCT_MLIB
@item 7
FF_IDCT_ARM
@item 8
FF_IDCT_ALTIVEC
@item 9
FF_IDCT_SH4
@item 10
FF_IDCT_SIMPLEARM
@end table

@item -er @var{n}
Set error resilience to @var{n}.
@table @samp
@item 1
FF_ER_CAREFUL (default)
@item 2
FF_ER_COMPLIANT
@item 3
FF_ER_AGGRESSIVE
@item 4
FF_ER_VERY_AGGRESSIVE
@end table

@item -ec @var{bit_mask}
Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
the following values:
@table @samp
@item 1
FF_EC_GUESS_MVS (default = enabled)
@item 2
FF_EC_DEBLOCK (default = enabled)
@end table

@item -bf @var{frames}
Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
@item -mbd @var{mode}
macroblock decision
@table @samp
@item 0
FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
@item 1
FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
@item 2
FF_MB_DECISION_RD: rate distortion
@end table

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

@item -deinterlace
Deinterlace pictures.
@item -ilme
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.
@item -psnr
Calculate PSNR of compressed frames.
@item -vstats
Dump video coding statistics to @file{vstats_HHMMSS.log}.
@item -vstats_file @var{file}
Dump video coding statistics to @var{file}.
@item -top @var{n}
top=1/bottom=0/auto=-1 field first
@item -dc @var{precision}
Intra_dc_precision.
@item -vtag @var{fourcc/tag}
Force video tag/fourcc.
@item -qphist
Show QP histogram.
@item -vbsf @var{bitstream_filter}
Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
@example
ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
@end example
@item -force_key_frames @var{time}[,@var{time}...]
Force key frames at the specified timestamps, more precisely at the first
frames after each specified time.
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.
The timestamps must be specified in ascending order.
@end table

@section Audio Options

@table @option
@item -aframes @var{number}
Set the number of audio frames to record.
@item -ar @var{freq}
Set the audio sampling frequency. For input streams it is set by
default to 44100 Hz, for output streams it is set by default to the
frequency of the input stream. If the input file has audio streams
with different frequencies, the behaviour is undefined.
@item -ab @var{bitrate}
Set the audio bitrate in bit/s (default = 64k).
@item -aq @var{q}
Set the audio quality (codec-specific, VBR).
@item -ac @var{channels}
Set the number of audio channels. For input streams it is set by
default to 1, for output streams it is set by default to the same
number of audio channels in input. If the input file has audio streams
with different channel count, the behaviour is undefined.
@item -an
Disable audio recording.
@item -acodec @var{codec}
Force audio codec to @var{codec}. Use the @code{copy} special value to
specify that the raw codec data must be copied as is.
@item -newaudio
Add a new audio track to the output file. If you want to specify parameters,
do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).

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

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

@section Advanced Audio options:

@table @option
@item -atag @var{fourcc/tag}
Force audio tag/fourcc.
@item -absf @var{bitstream_filter}
Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
@end table

@section Subtitle options:

@table @option
@item -scodec @var{codec}
Force subtitle codec ('copy' to copy stream).
@item -newsubtitle
Add a new subtitle stream to the current output stream.
@item -slang @var{code}
Set the ISO 639 language code (3 letters) of the current subtitle stream.
@item -sn
Disable subtitle recording.
@item -sbsf @var{bitstream_filter}
Bitstream filters available are "mov2textsub", "text2movsub".
@example
ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
@end example
@end table

@section Audio/Video grab options

@table @option
@item -vc @var{channel}
Set video grab channel (DV1394 only).
@item -tvstd @var{standard}
Set television standard (NTSC, PAL (SECAM)).
@item -isync
Synchronize read on input.
@end table

@section Advanced options

@table @option
@item -map @var{input_stream_id}[:@var{sync_stream_id}]
Set stream mapping from input streams to output streams.
Just enumerate the input streams in the order you want them in the output.
@var{sync_stream_id} if specified sets the input stream to sync
against.
@item -map_meta_data @var{outfile}[,@var{metadata}]:@var{infile}[,@var{metadata}]
Set meta data information of @var{outfile} from @var{infile}. Note that those
are file indices (zero-based), not filenames.
Optional @var{metadata} parameters specify, which metadata to copy - (g)lobal
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
per-(p)rogram. All metadata specifiers other than global must be followed by the
stream/chapter/program number. If metadata specifier is omitted, it defaults to
global.

By default, global metadata is copied from the first input file to all output files,
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.

For example to copy metadata from the first stream of the input file to global metadata
of the output file:
@example
ffmpeg -i in.ogg -map_meta_data 0:0,s0 out.mp3
@end example
@item -map_chapters @var{outfile}:@var{infile}
Copy chapters from @var{infile} to @var{outfile}. If no chapter mapping is specified,
then chapters are copied from the first input file with at least one chapter to all
output files. Use a negative file index to disable any chapter copying.
@item -debug
Print specific debug info.
@item -benchmark
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.
@item -dump
Dump each input packet.
@item -hex
When dumping packets, also dump the payload.
@item -bitexact
Only use bit exact algorithms (for codec testing).
@item -ps @var{size}
Set RTP payload size in bytes.
@item -re
Read input at native frame rate. Mainly used to simulate a grab device.
@item -loop_input
Loop over the input stream. Currently it works only for image
streams. This option is used for automatic FFserver testing.
@item -loop_output @var{number_of_times}
Repeatedly loop output for formats that support looping such as animated GIF
(0 will loop the output infinitely).
@item -threads @var{count}
Thread count.
@item -vsync @var{parameter}
Video sync method.
0   Each frame is passed with its timestamp from the demuxer to the muxer
1   Frames will be duplicated and dropped to achieve exactly the requested
    constant framerate.
2   Frames are passed through with their timestamp or dropped so as to prevent
    2 frames from having the same timestamp
-1  Chooses between 1 and 2 depending on muxer capabilities. This is the default method.

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.
@item -async @var{samples_per_second}
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
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.
@item -copyts
Copy timestamps from input to output.
@item -shortest
Finish encoding when the shortest input stream ends.
@item -dts_delta_threshold
Timestamp discontinuity delta threshold.
@item -muxdelay @var{seconds}
Set the maximum demux-decode delay.
@item -muxpreload @var{seconds}
Set the initial demux-decode delay.
@item -streamid @var{output-stream-index}:@var{new-value}
Assign a new value to a stream's stream-id field in the next output file.
All stream-id fields are reset to default for each output file.

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
@end table

@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
the @file{ffpresets} directory in the FFmpeg source tree for examples.

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
applied to the currently selected codec of the same type as the preset
option.

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:

First ffmpeg searches for a file named @var{arg}.ffpreset in the
directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
the datadir 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.ffpreset}.

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
the video codec with @code{-vcodec libx264} and use @code{-vpre max},
then it will search for the file @file{libx264-max.ffpreset}.
@c man end

@chapter Tips
@c man begin TIPS

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

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

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

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

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

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

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

@end itemize
@c man end TIPS

@chapter Examples
@c man begin EXAMPLES

@section Video and Audio grabbing

FFmpeg can grab video and audio from devices given that you specify the input
format and device.

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

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

@section X11 grabbing

FFmpeg can grab the X11 display.

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

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

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

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.

@section Video and Audio file format conversion

* FFmpeg can use any supported file format and protocol as input:

Examples:

* You can use YUV files as input:

@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
if FFmpeg cannot guess it.

* You can input from a raw YUV420P file:

@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.

* You can output to a raw YUV420P file:

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

* You can set several input files and output files:

@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.

* You can also do audio and video conversions at the same time:

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

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

* You can encode to several formats at the same time and define a
mapping from input stream to output streams:

@example
ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
@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.

* You can transcode decrypted VOBs:

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

* You can extract images from a video, or create a video from many images:

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
only formats accepting a normal integer are suitable.

* You can put many streams of the same type in the output:

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

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

The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
options have to be specified immediately after the name of the output
file to which you want to add them.
@c man end EXAMPLES

@include eval.texi
@include demuxers.texi
@include indevs.texi
@include outdevs.texi
@include protocols.texi
@include bitstream_filters.texi
@include filters.texi
@include metadata.texi

@ignore

@setfilename ffmpeg
@settitle FFmpeg video converter

@c man begin SEEALSO
ffplay(1), ffprobe(1), ffserver(1) and the FFmpeg HTML documentation
@c man end

@c man begin AUTHORS
The FFmpeg developers
@c man end

@end ignore

@bye