avconv: rename sameq to same_quant
[libav.git] / doc / avconv.texi
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1\input texinfo @c -*- texinfo -*-
2
3@settitle avconv Documentation
4@titlepage
5@center @titlefont{avconv Documentation}
6@end titlepage
7
8@top
9
10@contents
11
12@chapter Synopsis
13
14The generic syntax is:
15
16@example
17@c man begin SYNOPSIS
18avconv [[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
25avconv is a very fast video and audio converter that can also grab from
26a live audio/video source. It can also convert between arbitrary sample
27rates and resize video on the fly with a high quality polyphase filter.
28
29The command line interface is designed to be intuitive, in the sense
30that avconv tries to figure out all parameters that can possibly be
31derived automatically. You usually only have to specify the target
32bitrate you want.
33
34As a general rule, options are applied to the next specified
35file. Therefore, order is important, and you can have the same
36option on the command line multiple times. Each occurrence is
37then applied to the next input or output file.
38
39@itemize
40@item
41To set the video bitrate of the output file to 64kbit/s:
42@example
43avconv -i input.avi -b 64k output.avi
44@end example
45
46@item
47To force the frame rate of the output file to 24 fps:
48@example
49avconv -i input.avi -r 24 output.avi
50@end example
51
52@item
53To force the frame rate of the input file (valid for raw formats only)
54to 1 fps and the frame rate of the output file to 24 fps:
55@example
56avconv -r 1 -i input.m2v -r 24 output.avi
57@end example
58@end itemize
59
60The format option may be needed for raw input files.
61
62By default avconv tries to convert as losslessly as possible: It
63uses the same audio and video parameters for the outputs as the one
64specified for the inputs.
65
66@c man end DESCRIPTION
67
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68@chapter Stream selection
69@c man begin STREAM SELECTION
70
71By default av tries to pick the "best" stream of each type present in input
72files and add them to each output file. For video, this means the highest
73resolution, for audio the highest channel count. For subtitle it's simply the
74first subtitle stream.
75
76You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
77full manual control, use the @code{-map} option, which disables the defaults just
78described.
79
80@c man end STREAM SELECTION
81
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82@chapter Options
83@c man begin OPTIONS
84
85@include fftools-common-opts.texi
86
87@section Main options
88
89@table @option
90
91@item -f @var{fmt}
92Force format.
93
94@item -i @var{filename}
95input file name
96
97@item -y
98Overwrite output files.
99
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100@item -c[:@var{stream_type}][:@var{stream_index}] @var{codec}
101@item -codec[:@var{stream_type}][:@var{stream_index}] @var{codec}
102Select an encoder (when used before an output file) or a decoder (when used
103before an input file) for one or more streams. @var{codec} is the name of a
104decoder/encoder or a special value @code{copy} (output only) to indicate that
105the stream is not to be reencoded.
106
107@var{stream_type} may be 'v' for video, 'a' for audio, 's' for subtitle and 'd'
108for data streams. @var{stream_index} is a global zero-based stream index if
109@var{stream_type} isn't given, otherwise it counts only streams of the given
110type. If @var{stream_index} is omitted, this option applies to all streams of
111the given type or all streams of any type if @var{stream_type} is missing as
112well (note that this only makes sense when all streams are of the same type or
113@var{codec} is @code{copy}).
114
115For example
116@example
117avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
118@end example
119encodes all video streams with libx264 and copies all audio streams.
120
121For each stream, the last matching @code{c} option is applied, so
122@example
123avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
124@end example
125will copy all the streams except the second video, which will be encoded with
126libx264, and the 138th audio, which will be encoded with libvorbis.
127
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128@item -t @var{duration}
129Restrict the transcoded/captured video sequence
130to the duration specified in seconds.
131@code{hh:mm:ss[.xxx]} syntax is also supported.
132
133@item -fs @var{limit_size}
134Set the file size limit.
135
136@item -ss @var{position}
137Seek to given time position in seconds.
138@code{hh:mm:ss[.xxx]} syntax is also supported.
139
140@item -itsoffset @var{offset}
141Set the input time offset in seconds.
142@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
143This option affects all the input files that follow it.
144The offset is added to the timestamps of the input files.
145Specifying a positive offset means that the corresponding
146streams are delayed by 'offset' seconds.
147
148@item -timestamp @var{time}
149Set the recording timestamp in the container.
150The syntax for @var{time} is:
151@example
152now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
153@end example
154If the value is "now" it takes the current time.
155Time is local time unless 'Z' or 'z' is appended, in which case it is
156interpreted as UTC.
157If the year-month-day part is not specified it takes the current
158year-month-day.
159
160@item -metadata @var{key}=@var{value}
161Set a metadata key/value pair.
162
163For example, for setting the title in the output file:
164@example
165avconv -i in.avi -metadata title="my title" out.flv
166@end example
167
168@item -v @var{number}
169Set the logging verbosity level.
170
171@item -target @var{type}
172Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
173"ntsc-svcd", ... ). All the format options (bitrate, codecs,
174buffer sizes) are then set automatically. You can just type:
175
176@example
177avconv -i myfile.avi -target vcd /tmp/vcd.mpg
178@end example
179
180Nevertheless you can specify additional options as long as you know
181they do not conflict with the standard, as in:
182
183@example
184avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
185@end example
186
187@item -dframes @var{number}
188Set the number of data frames to record.
189
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190@item -slang @var{code}
191Set the ISO 639 language code (3 letters) of the current subtitle stream.
192
193@end table
194
195@section Video Options
196
197@table @option
198@item -vframes @var{number}
199Set the number of video frames to record.
200@item -r @var{fps}
201Set frame rate (Hz value, fraction or abbreviation), (default = 25).
202@item -s @var{size}
203Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
204The following abbreviations are recognized:
205@table @samp
206@item sqcif
207128x96
208@item qcif
209176x144
210@item cif
211352x288
212@item 4cif
213704x576
214@item 16cif
2151408x1152
216@item qqvga
217160x120
218@item qvga
219320x240
220@item vga
221640x480
222@item svga
223800x600
224@item xga
2251024x768
226@item uxga
2271600x1200
228@item qxga
2292048x1536
230@item sxga
2311280x1024
232@item qsxga
2332560x2048
234@item hsxga
2355120x4096
236@item wvga
237852x480
238@item wxga
2391366x768
240@item wsxga
2411600x1024
242@item wuxga
2431920x1200
244@item woxga
2452560x1600
246@item wqsxga
2473200x2048
248@item wquxga
2493840x2400
250@item whsxga
2516400x4096
252@item whuxga
2537680x4800
254@item cga
255320x200
256@item ega
257640x350
258@item hd480
259852x480
260@item hd720
2611280x720
262@item hd1080
2631920x1080
264@end table
265
266@item -aspect @var{aspect}
267Set the video display aspect ratio specified by @var{aspect}.
268
269@var{aspect} can be a floating point number string, or a string of the
270form @var{num}:@var{den}, where @var{num} and @var{den} are the
271numerator and denominator of the aspect ratio. For example "4:3",
272"16:9", "1.3333", and "1.7777" are valid argument values.
273
274@item -croptop @var{size}
275@item -cropbottom @var{size}
276@item -cropleft @var{size}
277@item -cropright @var{size}
278All the crop options have been removed. Use -vf
279crop=width:height:x:y instead.
280
281@item -padtop @var{size}
282@item -padbottom @var{size}
283@item -padleft @var{size}
284@item -padright @var{size}
285@item -padcolor @var{hex_color}
286All the pad options have been removed. Use -vf
287pad=width:height:x:y:color instead.
288@item -vn
289Disable video recording.
290@item -bt @var{tolerance}
291Set video bitrate tolerance (in bits, default 4000k).
292Has a minimum value of: (target_bitrate/target_framerate).
293In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
294willing to deviate from the target average bitrate value. This is
295not related to min/max bitrate. Lowering tolerance too much has
296an adverse effect on quality.
297@item -maxrate @var{bitrate}
298Set max video bitrate (in bit/s).
299Requires -bufsize to be set.
300@item -minrate @var{bitrate}
301Set min video bitrate (in bit/s).
302Most useful in setting up a CBR encode:
303@example
304avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
305@end example
306It is of little use elsewise.
307@item -bufsize @var{size}
308Set video buffer verifier buffer size (in bits).
309@item -vcodec @var{codec}
92f1940e 310Set the video codec. This is an alias for @code{-codec:v}.
f4ad238c 311@item -same_quant
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312Use same quantizer as source (implies VBR).
313
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314Note that this is NOT SAME QUALITY. Do not use this option unless you know you
315need it.
316
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317@item -pass @var{n}
318Select the pass number (1 or 2). It is used to do two-pass
319video encoding. The statistics of the video are recorded in the first
320pass into a log file (see also the option -passlogfile),
321and in the second pass that log file is used to generate the video
322at the exact requested bitrate.
323On pass 1, you may just deactivate audio and set output to null,
324examples for Windows and Unix:
325@example
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326avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
327avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
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328@end example
329
330@item -passlogfile @var{prefix}
331Set two-pass log file name prefix to @var{prefix}, the default file name
332prefix is ``av2pass''. The complete file name will be
333@file{PREFIX-N.log}, where N is a number specific to the output
334stream.
335
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336@item -vlang @var{code}
337Set the ISO 639 language code (3 letters) of the current video stream.
338
339@item -vf @var{filter_graph}
340@var{filter_graph} is a description of the filter graph to apply to
341the input video.
342Use the option "-filters" to show all the available filters (including
343also sources and sinks).
344
345@end table
346
347@section Advanced Video Options
348
349@table @option
350@item -pix_fmt @var{format}
351Set pixel format. Use 'list' as parameter to show all the supported
352pixel formats.
353@item -sws_flags @var{flags}
354Set SwScaler flags.
355@item -g @var{gop_size}
356Set the group of pictures size.
357@item -intra
358Use only intra frames.
359@item -vdt @var{n}
360Discard threshold.
361@item -qscale @var{q}
362Use fixed video quantizer scale (VBR).
363@item -qmin @var{q}
364minimum video quantizer scale (VBR)
365@item -qmax @var{q}
366maximum video quantizer scale (VBR)
367@item -qdiff @var{q}
368maximum difference between the quantizer scales (VBR)
369@item -qblur @var{blur}
370video quantizer scale blur (VBR) (range 0.0 - 1.0)
371@item -qcomp @var{compression}
372video quantizer scale compression (VBR) (default 0.5).
373Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
374
375@item -lmin @var{lambda}
376minimum video lagrange factor (VBR)
377@item -lmax @var{lambda}
378max video lagrange factor (VBR)
379@item -mblmin @var{lambda}
380minimum macroblock quantizer scale (VBR)
381@item -mblmax @var{lambda}
382maximum macroblock quantizer scale (VBR)
383
384These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
385but you may use the QP2LAMBDA constant to easily convert from 'q' units:
386@example
387avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
388@end example
389
390@item -rc_init_cplx @var{complexity}
391initial complexity for single pass encoding
392@item -b_qfactor @var{factor}
393qp factor between P- and B-frames
394@item -i_qfactor @var{factor}
395qp factor between P- and I-frames
396@item -b_qoffset @var{offset}
397qp offset between P- and B-frames
398@item -i_qoffset @var{offset}
399qp offset between P- and I-frames
400@item -rc_eq @var{equation}
401Set rate control equation (see section "Expression Evaluation")
402(default = @code{tex^qComp}).
403
404When computing the rate control equation expression, besides the
405standard functions defined in the section "Expression Evaluation", the
406following functions are available:
407@table @var
408@item bits2qp(bits)
409@item qp2bits(qp)
410@end table
411
412and the following constants are available:
413@table @var
414@item iTex
415@item pTex
416@item tex
417@item mv
418@item fCode
419@item iCount
420@item mcVar
421@item var
422@item isI
423@item isP
424@item isB
425@item avgQP
426@item qComp
427@item avgIITex
428@item avgPITex
429@item avgPPTex
430@item avgBPTex
431@item avgTex
432@end table
433
434@item -rc_override @var{override}
435rate control override for specific intervals
436@item -me_method @var{method}
437Set motion estimation method to @var{method}.
438Available methods are (from lowest to best quality):
439@table @samp
440@item zero
441Try just the (0, 0) vector.
442@item phods
443@item log
444@item x1
445@item hex
446@item umh
447@item epzs
448(default method)
449@item full
450exhaustive search (slow and marginally better than epzs)
451@end table
452
453@item -dct_algo @var{algo}
454Set DCT algorithm to @var{algo}. Available values are:
455@table @samp
456@item 0
457FF_DCT_AUTO (default)
458@item 1
459FF_DCT_FASTINT
460@item 2
461FF_DCT_INT
462@item 3
463FF_DCT_MMX
464@item 4
465FF_DCT_MLIB
466@item 5
467FF_DCT_ALTIVEC
468@end table
469
470@item -idct_algo @var{algo}
471Set IDCT algorithm to @var{algo}. Available values are:
472@table @samp
473@item 0
474FF_IDCT_AUTO (default)
475@item 1
476FF_IDCT_INT
477@item 2
478FF_IDCT_SIMPLE
479@item 3
480FF_IDCT_SIMPLEMMX
481@item 4
482FF_IDCT_LIBMPEG2MMX
483@item 5
484FF_IDCT_PS2
485@item 6
486FF_IDCT_MLIB
487@item 7
488FF_IDCT_ARM
489@item 8
490FF_IDCT_ALTIVEC
491@item 9
492FF_IDCT_SH4
493@item 10
494FF_IDCT_SIMPLEARM
495@end table
496
497@item -er @var{n}
498Set error resilience to @var{n}.
499@table @samp
500@item 1
501FF_ER_CAREFUL (default)
502@item 2
503FF_ER_COMPLIANT
504@item 3
505FF_ER_AGGRESSIVE
506@item 4
507FF_ER_VERY_AGGRESSIVE
508@end table
509
510@item -ec @var{bit_mask}
511Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
512the following values:
513@table @samp
514@item 1
515FF_EC_GUESS_MVS (default = enabled)
516@item 2
517FF_EC_DEBLOCK (default = enabled)
518@end table
519
520@item -bf @var{frames}
521Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
522@item -mbd @var{mode}
523macroblock decision
524@table @samp
525@item 0
526FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
527@item 1
528FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
529@item 2
530FF_MB_DECISION_RD: rate distortion
531@end table
532
533@item -4mv
534Use four motion vector by macroblock (MPEG-4 only).
535@item -part
536Use data partitioning (MPEG-4 only).
537@item -bug @var{param}
538Work around encoder bugs that are not auto-detected.
539@item -strict @var{strictness}
540How strictly to follow the standards.
541@item -aic
542Enable Advanced intra coding (h263+).
543@item -umv
544Enable Unlimited Motion Vector (h263+)
545
546@item -deinterlace
547Deinterlace pictures.
548@item -ilme
549Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
550Use this option if your input file is interlaced and you want
551to keep the interlaced format for minimum losses.
552The alternative is to deinterlace the input stream with
553@option{-deinterlace}, but deinterlacing introduces losses.
554@item -psnr
555Calculate PSNR of compressed frames.
556@item -vstats
557Dump video coding statistics to @file{vstats_HHMMSS.log}.
558@item -vstats_file @var{file}
559Dump video coding statistics to @var{file}.
560@item -top @var{n}
561top=1/bottom=0/auto=-1 field first
562@item -dc @var{precision}
563Intra_dc_precision.
564@item -vtag @var{fourcc/tag}
565Force video tag/fourcc.
566@item -qphist
567Show QP histogram.
568@item -vbsf @var{bitstream_filter}
569Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
570@example
92f1940e 571avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
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572@end example
573@item -force_key_frames @var{time}[,@var{time}...]
574Force key frames at the specified timestamps, more precisely at the first
575frames after each specified time.
576This option can be useful to ensure that a seek point is present at a
577chapter mark or any other designated place in the output file.
578The timestamps must be specified in ascending order.
579@end table
580
581@section Audio Options
582
583@table @option
584@item -aframes @var{number}
585Set the number of audio frames to record.
586@item -ar @var{freq}
587Set the audio sampling frequency. For output streams it is set by
588default to the frequency of the corresponding input stream. For input
589streams this option only makes sense for audio grabbing devices and raw
590demuxers and is mapped to the corresponding demuxer options.
591@item -aq @var{q}
592Set the audio quality (codec-specific, VBR).
593@item -ac @var{channels}
594Set the number of audio channels. For output streams it is set by
595default to the number of input audio channels. For input streams
596this option only makes sense for audio grabbing devices and raw demuxers
597and is mapped to the corresponding demuxer options.
598@item -an
599Disable audio recording.
600@item -acodec @var{codec}
92f1940e 601Set the audio codec. This is an alias for @code{-codec:a}.
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602@item -alang @var{code}
603Set the ISO 639 language code (3 letters) of the current audio stream.
604@end table
605
606@section Advanced Audio options:
607
608@table @option
609@item -atag @var{fourcc/tag}
610Force audio tag/fourcc.
611@item -audio_service_type @var{type}
612Set the type of service that the audio stream contains.
613@table @option
614@item ma
615Main Audio Service (default)
616@item ef
617Effects
618@item vi
619Visually Impaired
620@item hi
621Hearing Impaired
622@item di
623Dialogue
624@item co
625Commentary
626@item em
627Emergency
628@item vo
629Voice Over
630@item ka
631Karaoke
632@end table
633@item -absf @var{bitstream_filter}
634Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
635@end table
636
637@section Subtitle options:
638
639@table @option
640@item -scodec @var{codec}
92f1940e 641Set the subtitle codec. This is an alias for @code{-codec:s}.
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642@item -slang @var{code}
643Set the ISO 639 language code (3 letters) of the current subtitle stream.
644@item -sn
645Disable subtitle recording.
646@item -sbsf @var{bitstream_filter}
647Bitstream filters available are "mov2textsub", "text2movsub".
648@example
92f1940e 649avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
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650@end example
651@end table
652
653@section Audio/Video grab options
654
655@table @option
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656@item -isync
657Synchronize read on input.
658@end table
659
660@section Advanced options
661
662@table @option
8d2e4a7e 663@item -map [-]@var{input_file_id}[:@var{input_stream_type}][:@var{input_stream_id}][,@var{sync_file_id}[:@var{sync_stream_type}][:@var{sync_stream_id}]]
6291d7e4 664
8d2e4a7e 665Designate one or more input streams as a source for the output file. Each input
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666stream is identified by the input file index @var{input_file_id} and
667the input stream index @var{input_stream_id} within the input
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668file. Both indices start at 0. If specified,
669@var{sync_file_id}:@var{sync_stream_id} sets which input stream
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670is used as a presentation sync reference.
671
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672If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
673subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
674of this type. Same for @var{sync_stream_type}.
675
676@var{input_stream_id} may be omitted, in which case all streams of the given
677type are mapped (or all streams in the file, if no type is specified).
678
3d4f0dab 679The first @code{-map} option on the command line specifies the
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680source for output stream 0, the second @code{-map} option specifies
681the source for output stream 1, etc.
682
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683A @code{-} character before the stream identifier creates a "negative" mapping.
684It disables matching streams from already created mappings.
685
686For example, to map ALL streams from the first input file to output
687@example
688av -i INPUT -map 0 output
689@end example
690
6291d7e4 691For example, if you have two audio streams in the first input file,
8d2e4a7e 692these streams are identified by "0:0" and "0:1". You can use
3d4f0dab 693@code{-map} to select which streams to place in an output file. For
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694example:
695@example
8d2e4a7e 696avconv -i INPUT -map 0:1 out.wav
6291d7e4 697@end example
8d2e4a7e 698will map the input stream in @file{INPUT} identified by "0:1" to
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699the (single) output stream in @file{out.wav}.
700
701For example, to select the stream with index 2 from input file
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702@file{a.mov} (specified by the identifier "0:2"), and stream with
703index 6 from input @file{b.mov} (specified by the identifier "1:6"),
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704and copy them to the output file @file{out.mov}:
705@example
92f1940e 706avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
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707@end example
708
709To select all video and the third audio stream from an input file:
710@example
711avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
712@end example
713
714To map all the streams except the second audio, use negative mappings
715@example
716avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
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717@end example
718
3d4f0dab 719Note that using this option disables the default mappings for this output file.
6291d7e4 720
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721@item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
722Set metadata information of the next output file from @var{infile}. Note that
723those are file indices (zero-based), not filenames.
724Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
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725(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
726per-(p)rogram. All metadata specifiers other than global must be followed by the
e6e6060c 727stream/chapter/program index. If metadata specifier is omitted, it defaults to
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728global.
729
e6e6060c 730By default, global metadata is copied from the first input file,
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731per-stream and per-chapter metadata is copied along with streams/chapters. These
732default mappings are disabled by creating any mapping of the relevant type. A negative
733file index can be used to create a dummy mapping that just disables automatic copying.
734
735For example to copy metadata from the first stream of the input file to global metadata
736of the output file:
737@example
e6e6060c 738avconv -i in.ogg -map_metadata 0:s:0 out.mp3
6291d7e4 739@end example
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740@item -map_chapters @var{input_file_index}
741Copy chapters from input file with index @var{input_file_index} to the next
742output file. If no chapter mapping is specified, then chapters are copied from
743the first input file with at least one chapter. Use a negative file index to
744disable any chapter copying.
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745@item -debug
746Print specific debug info.
747@item -benchmark
748Show benchmarking information at the end of an encode.
749Shows CPU time used and maximum memory consumption.
750Maximum memory consumption is not supported on all systems,
751it will usually display as 0 if not supported.
752@item -dump
753Dump each input packet.
754@item -hex
755When dumping packets, also dump the payload.
756@item -bitexact
757Only use bit exact algorithms (for codec testing).
758@item -ps @var{size}
759Set RTP payload size in bytes.
760@item -re
761Read input at native frame rate. Mainly used to simulate a grab device.
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762@item -threads @var{count}
763Thread count.
764@item -vsync @var{parameter}
765Video sync method.
766
767@table @option
768@item 0
769Each frame is passed with its timestamp from the demuxer to the muxer.
770@item 1
771Frames will be duplicated and dropped to achieve exactly the requested
772constant framerate.
773@item 2
774Frames are passed through with their timestamp or dropped so as to
775prevent 2 frames from having the same timestamp.
776@item -1
777Chooses between 1 and 2 depending on muxer capabilities. This is the
778default method.
779@end table
780
781With -map you can select from which stream the timestamps should be
782taken. You can leave either video or audio unchanged and sync the
783remaining stream(s) to the unchanged one.
784
785@item -async @var{samples_per_second}
786Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
787the parameter is the maximum samples per second by which the audio is changed.
788-async 1 is a special case where only the start of the audio stream is corrected
789without any later correction.
790@item -copyts
791Copy timestamps from input to output.
792@item -copytb
793Copy input stream time base from input to output when stream copying.
794@item -shortest
795Finish encoding when the shortest input stream ends.
796@item -dts_delta_threshold
797Timestamp discontinuity delta threshold.
798@item -muxdelay @var{seconds}
799Set the maximum demux-decode delay.
800@item -muxpreload @var{seconds}
801Set the initial demux-decode delay.
802@item -streamid @var{output-stream-index}:@var{new-value}
803Assign a new stream-id value to an output stream. This option should be
804specified prior to the output filename to which it applies.
805For the situation where multiple output files exist, a streamid
806may be reassigned to a different value.
807
808For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
809an output mpegts file:
810@example
811avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
812@end example
813@end table
7478ab5a 814@c man end OPTIONS
6291d7e4 815
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816@chapter Tips
817@c man begin TIPS
818
819@itemize
820@item
821For streaming at very low bitrate application, use a low frame rate
822and a small GOP size. This is especially true for RealVideo where
823the Linux player does not seem to be very fast, so it can miss
824frames. An example is:
825
826@example
827avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
828@end example
829
830@item
831The parameter 'q' which is displayed while encoding is the current
832quantizer. The value 1 indicates that a very good quality could
833be achieved. The value 31 indicates the worst quality. If q=31 appears
834too often, it means that the encoder cannot compress enough to meet
835your bitrate. You must either increase the bitrate, decrease the
836frame rate or decrease the frame size.
837
838@item
839If your computer is not fast enough, you can speed up the
840compression at the expense of the compression ratio. You can use
841'-me zero' to speed up motion estimation, and '-intra' to disable
842motion estimation completely (you have only I-frames, which means it
843is about as good as JPEG compression).
844
845@item
846To have very low audio bitrates, reduce the sampling frequency
847(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
848
849@item
850To have a constant quality (but a variable bitrate), use the option
851'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
852quality).
853
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854@end itemize
855@c man end TIPS
856
857@chapter Examples
858@c man begin EXAMPLES
859
860@section Video and Audio grabbing
861
862If you specify the input format and device then avconv can grab video
863and audio directly.
864
865@example
866avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
867@end example
868
869Note that you must activate the right video source and channel before
870launching avconv with any TV viewer such as
871@uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
872have to set the audio recording levels correctly with a
873standard mixer.
874
875@section X11 grabbing
876
877Grab the X11 display with avconv via
878
879@example
880avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
881@end example
882
8830.0 is display.screen number of your X11 server, same as
884the DISPLAY environment variable.
885
886@example
887avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
888@end example
889
8900.0 is display.screen number of your X11 server, same as the DISPLAY environment
891variable. 10 is the x-offset and 20 the y-offset for the grabbing.
892
893@section Video and Audio file format conversion
894
895Any supported file format and protocol can serve as input to avconv:
896
897Examples:
898@itemize
899@item
900You can use YUV files as input:
901
902@example
903avconv -i /tmp/test%d.Y /tmp/out.mpg
904@end example
905
906It will use the files:
907@example
908/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
909/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
910@end example
911
912The Y files use twice the resolution of the U and V files. They are
913raw files, without header. They can be generated by all decent video
914decoders. You must specify the size of the image with the @option{-s} option
915if avconv cannot guess it.
916
917@item
918You can input from a raw YUV420P file:
919
920@example
921avconv -i /tmp/test.yuv /tmp/out.avi
922@end example
923
924test.yuv is a file containing raw YUV planar data. Each frame is composed
925of the Y plane followed by the U and V planes at half vertical and
926horizontal resolution.
927
928@item
929You can output to a raw YUV420P file:
930
931@example
932avconv -i mydivx.avi hugefile.yuv
933@end example
934
935@item
936You can set several input files and output files:
937
938@example
939avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
940@end example
941
942Converts the audio file a.wav and the raw YUV video file a.yuv
943to MPEG file a.mpg.
944
945@item
946You can also do audio and video conversions at the same time:
947
948@example
949avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
950@end example
951
952Converts a.wav to MPEG audio at 22050 Hz sample rate.
953
954@item
955You can encode to several formats at the same time and define a
956mapping from input stream to output streams:
957
958@example
8d2e4a7e 959avconv -i /tmp/a.wav -map 0:a -ab 64k /tmp/a.mp2 -map 0:a -ab 128k /tmp/b.mp2
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960@end example
961
962Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
963file:index' specifies which input stream is used for each output
964stream, in the order of the definition of output streams.
965
966@item
967You can transcode decrypted VOBs:
968
969@example
92f1940e 970avconv -i snatch_1.vob -f avi -c:v mpeg4 -b 800k -g 300 -bf 2 -c:a libmp3lame -ab 128k snatch.avi
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971@end example
972
973This is a typical DVD ripping example; the input is a VOB file, the
974output an AVI file with MPEG-4 video and MP3 audio. Note that in this
975command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
976GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
977input video. Furthermore, the audio stream is MP3-encoded so you need
978to enable LAME support by passing @code{--enable-libmp3lame} to configure.
979The mapping is particularly useful for DVD transcoding
980to get the desired audio language.
981
982NOTE: To see the supported input formats, use @code{avconv -formats}.
983
984@item
985You can extract images from a video, or create a video from many images:
986
987For extracting images from a video:
988@example
989avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
990@end example
991
992This will extract one video frame per second from the video and will
993output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
994etc. Images will be rescaled to fit the new WxH values.
995
996If you want to extract just a limited number of frames, you can use the
997above command in combination with the -vframes or -t option, or in
998combination with -ss to start extracting from a certain point in time.
999
1000For creating a video from many images:
1001@example
1002avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1003@end example
1004
1005The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1006composed of three digits padded with zeroes to express the sequence
1007number. It is the same syntax supported by the C printf function, but
1008only formats accepting a normal integer are suitable.
1009
1010@item
1011You can put many streams of the same type in the output:
1012
1013@example
92f1940e 1014avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
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1015@end example
1016
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1017The resulting output file @file{test12.avi} will contain first four streams from
1018the input file in reverse order.
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1019
1020@end itemize
1021@c man end EXAMPLES
1022
1023@include eval.texi
1024@include encoders.texi
1025@include demuxers.texi
1026@include muxers.texi
1027@include indevs.texi
1028@include outdevs.texi
1029@include protocols.texi
1030@include bitstream_filters.texi
1031@include filters.texi
1032@include metadata.texi
1033
1034@ignore
1035
1036@setfilename avconv
1037@settitle avconv video converter
1038
1039@c man begin SEEALSO
1040avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1041@c man end
1042
1043@c man begin AUTHORS
1044The Libav developers
1045@c man end
1046
1047@end ignore
1048
1049@bye