avconv: move audio_sample_fmt to options context.
[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
f5bae2c6 71By default avconv tries to pick the "best" stream of each type present in input
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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}
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137When used as an input option (before @code{-i}), seeks in this input file to
138@var{position}. When used as an output option (before an output filename),
139decodes but discards input until the timestamps reach @var{position}. This is
140slower, but more accurate.
141
142@var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
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143
144@item -itsoffset @var{offset}
145Set the input time offset in seconds.
146@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
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147The offset is added to the timestamps of the input files.
148Specifying a positive offset means that the corresponding
149streams are delayed by 'offset' seconds.
150
151@item -timestamp @var{time}
152Set the recording timestamp in the container.
153The syntax for @var{time} is:
154@example
155now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
156@end example
157If the value is "now" it takes the current time.
158Time is local time unless 'Z' or 'z' is appended, in which case it is
159interpreted as UTC.
160If the year-month-day part is not specified it takes the current
161year-month-day.
162
039267f1 163@item -metadata[:metadata_specifier] @var{key}=@var{value}
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164Set a metadata key/value pair.
165
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166An optional @var{metadata_specifier} may be given to set metadata
167on streams or chapters. See @code{-map_metadata} documentation for
168details.
169
170This option overrides metadata set with @code{-map_metadata}. It is
171also possible to delete metadata by using an empty value.
172
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173For example, for setting the title in the output file:
174@example
175avconv -i in.avi -metadata title="my title" out.flv
176@end example
177
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178To set the language of the second stream:
179@example
180avconv -i INPUT -metadata:s:1 language=eng OUTPUT
181@end example
182
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183@item -v @var{number}
184Set the logging verbosity level.
185
186@item -target @var{type}
187Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
188"ntsc-svcd", ... ). All the format options (bitrate, codecs,
189buffer sizes) are then set automatically. You can just type:
190
191@example
192avconv -i myfile.avi -target vcd /tmp/vcd.mpg
193@end example
194
195Nevertheless you can specify additional options as long as you know
196they do not conflict with the standard, as in:
197
198@example
199avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
200@end example
201
202@item -dframes @var{number}
96139b5e 203Set the number of data frames to record. This is an alias for @code{-frames:d}.
6291d7e4 204
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205@item -frames[:stream_specifier] @var{framecount}
206Stop writing to the stream after @var{framecount} frames.
207
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208@end table
209
210@section Video Options
211
212@table @option
213@item -vframes @var{number}
96139b5e 214Set the number of video frames to record. This is an alias for @code{-frames:v}.
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215@item -r @var{fps}
216Set frame rate (Hz value, fraction or abbreviation), (default = 25).
217@item -s @var{size}
218Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
219The following abbreviations are recognized:
220@table @samp
221@item sqcif
222128x96
223@item qcif
224176x144
225@item cif
226352x288
227@item 4cif
228704x576
229@item 16cif
2301408x1152
231@item qqvga
232160x120
233@item qvga
234320x240
235@item vga
236640x480
237@item svga
238800x600
239@item xga
2401024x768
241@item uxga
2421600x1200
243@item qxga
2442048x1536
245@item sxga
2461280x1024
247@item qsxga
2482560x2048
249@item hsxga
2505120x4096
251@item wvga
252852x480
253@item wxga
2541366x768
255@item wsxga
2561600x1024
257@item wuxga
2581920x1200
259@item woxga
2602560x1600
261@item wqsxga
2623200x2048
263@item wquxga
2643840x2400
265@item whsxga
2666400x4096
267@item whuxga
2687680x4800
269@item cga
270320x200
271@item ega
272640x350
273@item hd480
274852x480
275@item hd720
2761280x720
277@item hd1080
2781920x1080
279@end table
280
281@item -aspect @var{aspect}
282Set the video display aspect ratio specified by @var{aspect}.
283
284@var{aspect} can be a floating point number string, or a string of the
285form @var{num}:@var{den}, where @var{num} and @var{den} are the
286numerator and denominator of the aspect ratio. For example "4:3",
287"16:9", "1.3333", and "1.7777" are valid argument values.
288
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289@item -vn
290Disable video recording.
291@item -bt @var{tolerance}
292Set video bitrate tolerance (in bits, default 4000k).
293Has a minimum value of: (target_bitrate/target_framerate).
294In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
295willing to deviate from the target average bitrate value. This is
296not related to min/max bitrate. Lowering tolerance too much has
297an adverse effect on quality.
298@item -maxrate @var{bitrate}
299Set max video bitrate (in bit/s).
300Requires -bufsize to be set.
301@item -minrate @var{bitrate}
302Set min video bitrate (in bit/s).
303Most useful in setting up a CBR encode:
304@example
305avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
306@end example
307It is of little use elsewise.
308@item -bufsize @var{size}
309Set video buffer verifier buffer size (in bits).
310@item -vcodec @var{codec}
92f1940e 311Set the video codec. This is an alias for @code{-codec:v}.
f4ad238c 312@item -same_quant
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313Use same quantizer as source (implies VBR).
314
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315Note that this is NOT SAME QUALITY. Do not use this option unless you know you
316need it.
317
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318@item -pass @var{n}
319Select the pass number (1 or 2). It is used to do two-pass
320video encoding. The statistics of the video are recorded in the first
321pass into a log file (see also the option -passlogfile),
322and in the second pass that log file is used to generate the video
323at the exact requested bitrate.
324On pass 1, you may just deactivate audio and set output to null,
325examples for Windows and Unix:
326@example
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327avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
328avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
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329@end example
330
331@item -passlogfile @var{prefix}
332Set two-pass log file name prefix to @var{prefix}, the default file name
333prefix is ``av2pass''. The complete file name will be
334@file{PREFIX-N.log}, where N is a number specific to the output
335stream.
336
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337@item -vf @var{filter_graph}
338@var{filter_graph} is a description of the filter graph to apply to
339the input video.
340Use the option "-filters" to show all the available filters (including
341also sources and sinks).
342
343@end table
344
345@section Advanced Video Options
346
347@table @option
348@item -pix_fmt @var{format}
349Set pixel format. Use 'list' as parameter to show all the supported
350pixel formats.
351@item -sws_flags @var{flags}
352Set SwScaler flags.
353@item -g @var{gop_size}
354Set the group of pictures size.
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355@item -vdt @var{n}
356Discard threshold.
357@item -qscale @var{q}
358Use fixed video quantizer scale (VBR).
359@item -qmin @var{q}
360minimum video quantizer scale (VBR)
361@item -qmax @var{q}
362maximum video quantizer scale (VBR)
363@item -qdiff @var{q}
364maximum difference between the quantizer scales (VBR)
365@item -qblur @var{blur}
366video quantizer scale blur (VBR) (range 0.0 - 1.0)
367@item -qcomp @var{compression}
368video quantizer scale compression (VBR) (default 0.5).
369Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
370
371@item -lmin @var{lambda}
372minimum video lagrange factor (VBR)
373@item -lmax @var{lambda}
374max video lagrange factor (VBR)
375@item -mblmin @var{lambda}
376minimum macroblock quantizer scale (VBR)
377@item -mblmax @var{lambda}
378maximum macroblock quantizer scale (VBR)
379
380These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
381but you may use the QP2LAMBDA constant to easily convert from 'q' units:
382@example
383avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
384@end example
385
386@item -rc_init_cplx @var{complexity}
387initial complexity for single pass encoding
388@item -b_qfactor @var{factor}
389qp factor between P- and B-frames
390@item -i_qfactor @var{factor}
391qp factor between P- and I-frames
392@item -b_qoffset @var{offset}
393qp offset between P- and B-frames
394@item -i_qoffset @var{offset}
395qp offset between P- and I-frames
396@item -rc_eq @var{equation}
397Set rate control equation (see section "Expression Evaluation")
398(default = @code{tex^qComp}).
399
400When computing the rate control equation expression, besides the
401standard functions defined in the section "Expression Evaluation", the
402following functions are available:
403@table @var
404@item bits2qp(bits)
405@item qp2bits(qp)
406@end table
407
408and the following constants are available:
409@table @var
410@item iTex
411@item pTex
412@item tex
413@item mv
414@item fCode
415@item iCount
416@item mcVar
417@item var
418@item isI
419@item isP
420@item isB
421@item avgQP
422@item qComp
423@item avgIITex
424@item avgPITex
425@item avgPPTex
426@item avgBPTex
427@item avgTex
428@end table
429
430@item -rc_override @var{override}
431rate control override for specific intervals
432@item -me_method @var{method}
433Set motion estimation method to @var{method}.
434Available methods are (from lowest to best quality):
435@table @samp
436@item zero
437Try just the (0, 0) vector.
438@item phods
439@item log
440@item x1
441@item hex
442@item umh
443@item epzs
444(default method)
445@item full
446exhaustive search (slow and marginally better than epzs)
447@end table
448
449@item -dct_algo @var{algo}
450Set DCT algorithm to @var{algo}. Available values are:
451@table @samp
452@item 0
453FF_DCT_AUTO (default)
454@item 1
455FF_DCT_FASTINT
456@item 2
457FF_DCT_INT
458@item 3
459FF_DCT_MMX
460@item 4
461FF_DCT_MLIB
462@item 5
463FF_DCT_ALTIVEC
464@end table
465
466@item -idct_algo @var{algo}
467Set IDCT algorithm to @var{algo}. Available values are:
468@table @samp
469@item 0
470FF_IDCT_AUTO (default)
471@item 1
472FF_IDCT_INT
473@item 2
474FF_IDCT_SIMPLE
475@item 3
476FF_IDCT_SIMPLEMMX
477@item 4
478FF_IDCT_LIBMPEG2MMX
479@item 5
480FF_IDCT_PS2
481@item 6
482FF_IDCT_MLIB
483@item 7
484FF_IDCT_ARM
485@item 8
486FF_IDCT_ALTIVEC
487@item 9
488FF_IDCT_SH4
489@item 10
490FF_IDCT_SIMPLEARM
491@end table
492
493@item -er @var{n}
494Set error resilience to @var{n}.
495@table @samp
496@item 1
497FF_ER_CAREFUL (default)
498@item 2
499FF_ER_COMPLIANT
500@item 3
501FF_ER_AGGRESSIVE
502@item 4
503FF_ER_VERY_AGGRESSIVE
504@end table
505
506@item -ec @var{bit_mask}
507Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
508the following values:
509@table @samp
510@item 1
511FF_EC_GUESS_MVS (default = enabled)
512@item 2
513FF_EC_DEBLOCK (default = enabled)
514@end table
515
516@item -bf @var{frames}
517Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
518@item -mbd @var{mode}
519macroblock decision
520@table @samp
521@item 0
522FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
523@item 1
524FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
525@item 2
526FF_MB_DECISION_RD: rate distortion
527@end table
528
529@item -4mv
530Use four motion vector by macroblock (MPEG-4 only).
531@item -part
532Use data partitioning (MPEG-4 only).
533@item -bug @var{param}
534Work around encoder bugs that are not auto-detected.
535@item -strict @var{strictness}
536How strictly to follow the standards.
537@item -aic
538Enable Advanced intra coding (h263+).
539@item -umv
540Enable Unlimited Motion Vector (h263+)
541
542@item -deinterlace
543Deinterlace pictures.
544@item -ilme
545Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
546Use this option if your input file is interlaced and you want
547to keep the interlaced format for minimum losses.
548The alternative is to deinterlace the input stream with
549@option{-deinterlace}, but deinterlacing introduces losses.
550@item -psnr
551Calculate PSNR of compressed frames.
552@item -vstats
553Dump video coding statistics to @file{vstats_HHMMSS.log}.
554@item -vstats_file @var{file}
555Dump video coding statistics to @var{file}.
556@item -top @var{n}
557top=1/bottom=0/auto=-1 field first
558@item -dc @var{precision}
559Intra_dc_precision.
560@item -vtag @var{fourcc/tag}
013887eb 561Force video tag/fourcc. This is an alias for @code{-tag:v}.
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562@item -qphist
563Show QP histogram.
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564@item -force_key_frames @var{time}[,@var{time}...]
565Force key frames at the specified timestamps, more precisely at the first
566frames after each specified time.
567This option can be useful to ensure that a seek point is present at a
568chapter mark or any other designated place in the output file.
569The timestamps must be specified in ascending order.
570@end table
571
572@section Audio Options
573
574@table @option
575@item -aframes @var{number}
96139b5e 576Set the number of audio frames to record. This is an alias for @code{-frames:a}.
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577@item -ar @var{freq}
578Set the audio sampling frequency. For output streams it is set by
579default to the frequency of the corresponding input stream. For input
580streams this option only makes sense for audio grabbing devices and raw
581demuxers and is mapped to the corresponding demuxer options.
582@item -aq @var{q}
583Set the audio quality (codec-specific, VBR).
584@item -ac @var{channels}
585Set the number of audio channels. For output streams it is set by
586default to the number of input audio channels. For input streams
587this option only makes sense for audio grabbing devices and raw demuxers
588and is mapped to the corresponding demuxer options.
589@item -an
590Disable audio recording.
591@item -acodec @var{codec}
92f1940e 592Set the audio codec. This is an alias for @code{-codec:a}.
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593@item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt}
594Set the audio sample format. Use @code{-help sample_fmts} to get a list
595of supported sample formats.
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596@end table
597
598@section Advanced Audio options:
599
600@table @option
601@item -atag @var{fourcc/tag}
013887eb 602Force audio tag/fourcc. This is an alias for @code{-tag:a}.
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603@item -audio_service_type @var{type}
604Set the type of service that the audio stream contains.
605@table @option
606@item ma
607Main Audio Service (default)
608@item ef
609Effects
610@item vi
611Visually Impaired
612@item hi
613Hearing Impaired
614@item di
615Dialogue
616@item co
617Commentary
618@item em
619Emergency
620@item vo
621Voice Over
622@item ka
623Karaoke
624@end table
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625@end table
626
627@section Subtitle options:
628
629@table @option
630@item -scodec @var{codec}
92f1940e 631Set the subtitle codec. This is an alias for @code{-codec:s}.
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632@item -sn
633Disable subtitle recording.
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634@end table
635
636@section Audio/Video grab options
637
638@table @option
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639@item -isync
640Synchronize read on input.
641@end table
642
643@section Advanced options
644
645@table @option
8d2e4a7e 646@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 647
8d2e4a7e 648Designate one or more input streams as a source for the output file. Each input
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649stream is identified by the input file index @var{input_file_id} and
650the input stream index @var{input_stream_id} within the input
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651file. Both indices start at 0. If specified,
652@var{sync_file_id}:@var{sync_stream_id} sets which input stream
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653is used as a presentation sync reference.
654
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655If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
656subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
657of this type. Same for @var{sync_stream_type}.
658
659@var{input_stream_id} may be omitted, in which case all streams of the given
660type are mapped (or all streams in the file, if no type is specified).
661
3d4f0dab 662The first @code{-map} option on the command line specifies the
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663source for output stream 0, the second @code{-map} option specifies
664the source for output stream 1, etc.
665
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666A @code{-} character before the stream identifier creates a "negative" mapping.
667It disables matching streams from already created mappings.
668
669For example, to map ALL streams from the first input file to output
670@example
f5bae2c6 671avconv -i INPUT -map 0 output
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672@end example
673
6291d7e4 674For example, if you have two audio streams in the first input file,
8d2e4a7e 675these streams are identified by "0:0" and "0:1". You can use
3d4f0dab 676@code{-map} to select which streams to place in an output file. For
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677example:
678@example
8d2e4a7e 679avconv -i INPUT -map 0:1 out.wav
6291d7e4 680@end example
8d2e4a7e 681will map the input stream in @file{INPUT} identified by "0:1" to
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682the (single) output stream in @file{out.wav}.
683
684For example, to select the stream with index 2 from input file
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685@file{a.mov} (specified by the identifier "0:2"), and stream with
686index 6 from input @file{b.mov} (specified by the identifier "1:6"),
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687and copy them to the output file @file{out.mov}:
688@example
92f1940e 689avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
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690@end example
691
692To select all video and the third audio stream from an input file:
693@example
694avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
695@end example
696
697To map all the streams except the second audio, use negative mappings
698@example
699avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
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700@end example
701
3d4f0dab 702Note that using this option disables the default mappings for this output file.
6291d7e4 703
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704@item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
705Set metadata information of the next output file from @var{infile}. Note that
706those are file indices (zero-based), not filenames.
707Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
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708(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
709per-(p)rogram. All metadata specifiers other than global must be followed by the
e6e6060c 710stream/chapter/program index. If metadata specifier is omitted, it defaults to
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711global.
712
e6e6060c 713By default, global metadata is copied from the first input file,
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714per-stream and per-chapter metadata is copied along with streams/chapters. These
715default mappings are disabled by creating any mapping of the relevant type. A negative
716file index can be used to create a dummy mapping that just disables automatic copying.
717
718For example to copy metadata from the first stream of the input file to global metadata
719of the output file:
720@example
e6e6060c 721avconv -i in.ogg -map_metadata 0:s:0 out.mp3
6291d7e4 722@end example
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723@item -map_chapters @var{input_file_index}
724Copy chapters from input file with index @var{input_file_index} to the next
725output file. If no chapter mapping is specified, then chapters are copied from
726the first input file with at least one chapter. Use a negative file index to
727disable any chapter copying.
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728@item -debug
729Print specific debug info.
730@item -benchmark
731Show benchmarking information at the end of an encode.
732Shows CPU time used and maximum memory consumption.
733Maximum memory consumption is not supported on all systems,
734it will usually display as 0 if not supported.
735@item -dump
736Dump each input packet.
737@item -hex
738When dumping packets, also dump the payload.
739@item -bitexact
740Only use bit exact algorithms (for codec testing).
741@item -ps @var{size}
742Set RTP payload size in bytes.
743@item -re
744Read input at native frame rate. Mainly used to simulate a grab device.
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745@item -threads @var{count}
746Thread count.
747@item -vsync @var{parameter}
748Video sync method.
749
750@table @option
751@item 0
752Each frame is passed with its timestamp from the demuxer to the muxer.
753@item 1
754Frames will be duplicated and dropped to achieve exactly the requested
755constant framerate.
756@item 2
757Frames are passed through with their timestamp or dropped so as to
758prevent 2 frames from having the same timestamp.
759@item -1
760Chooses between 1 and 2 depending on muxer capabilities. This is the
761default method.
762@end table
763
764With -map you can select from which stream the timestamps should be
765taken. You can leave either video or audio unchanged and sync the
766remaining stream(s) to the unchanged one.
767
768@item -async @var{samples_per_second}
769Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
770the parameter is the maximum samples per second by which the audio is changed.
771-async 1 is a special case where only the start of the audio stream is corrected
772without any later correction.
773@item -copyts
774Copy timestamps from input to output.
775@item -copytb
776Copy input stream time base from input to output when stream copying.
777@item -shortest
778Finish encoding when the shortest input stream ends.
779@item -dts_delta_threshold
780Timestamp discontinuity delta threshold.
781@item -muxdelay @var{seconds}
782Set the maximum demux-decode delay.
783@item -muxpreload @var{seconds}
784Set the initial demux-decode delay.
785@item -streamid @var{output-stream-index}:@var{new-value}
786Assign a new stream-id value to an output stream. This option should be
787specified prior to the output filename to which it applies.
788For the situation where multiple output files exist, a streamid
789may be reassigned to a different value.
790
791For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
792an output mpegts file:
793@example
794avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
795@end example
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796
797@item -bsf[:@var{stream_specifier}] @var{bitstream_filters}
798Set bitstream filters for matching streams. @var{bistream_filters} is
799a comma-separated list of bitstream filters. Use the @code{-bsfs} option
800to get the list of bitstream filters.
801@example
802avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
803@end example
804@example
805avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
806@end example
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807
808@item -tag[:@var{stream_specifier}] @var{codec_tag}
809Force a tag/fourcc for matching streams.
6291d7e4 810@end table
7478ab5a 811@c man end OPTIONS
6291d7e4 812
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813@chapter Tips
814@c man begin TIPS
815
816@itemize
817@item
818For streaming at very low bitrate application, use a low frame rate
819and a small GOP size. This is especially true for RealVideo where
820the Linux player does not seem to be very fast, so it can miss
821frames. An example is:
822
823@example
824avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
825@end example
826
827@item
828The parameter 'q' which is displayed while encoding is the current
829quantizer. The value 1 indicates that a very good quality could
830be achieved. The value 31 indicates the worst quality. If q=31 appears
831too often, it means that the encoder cannot compress enough to meet
832your bitrate. You must either increase the bitrate, decrease the
833frame rate or decrease the frame size.
834
835@item
836If your computer is not fast enough, you can speed up the
837compression at the expense of the compression ratio. You can use
838'-me zero' to speed up motion estimation, and '-intra' to disable
839motion estimation completely (you have only I-frames, which means it
840is about as good as JPEG compression).
841
842@item
843To have very low audio bitrates, reduce the sampling frequency
844(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
845
846@item
847To have a constant quality (but a variable bitrate), use the option
848'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
849quality).
850
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851@end itemize
852@c man end TIPS
853
854@chapter Examples
855@c man begin EXAMPLES
856
857@section Video and Audio grabbing
858
859If you specify the input format and device then avconv can grab video
860and audio directly.
861
862@example
863avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
864@end example
865
866Note that you must activate the right video source and channel before
867launching avconv with any TV viewer such as
868@uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
869have to set the audio recording levels correctly with a
870standard mixer.
871
872@section X11 grabbing
873
874Grab the X11 display with avconv via
875
876@example
877avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
878@end example
879
8800.0 is display.screen number of your X11 server, same as
881the DISPLAY environment variable.
882
883@example
884avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
885@end example
886
8870.0 is display.screen number of your X11 server, same as the DISPLAY environment
888variable. 10 is the x-offset and 20 the y-offset for the grabbing.
889
890@section Video and Audio file format conversion
891
892Any supported file format and protocol can serve as input to avconv:
893
894Examples:
895@itemize
896@item
897You can use YUV files as input:
898
899@example
900avconv -i /tmp/test%d.Y /tmp/out.mpg
901@end example
902
903It will use the files:
904@example
905/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
906/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
907@end example
908
909The Y files use twice the resolution of the U and V files. They are
910raw files, without header. They can be generated by all decent video
911decoders. You must specify the size of the image with the @option{-s} option
912if avconv cannot guess it.
913
914@item
915You can input from a raw YUV420P file:
916
917@example
918avconv -i /tmp/test.yuv /tmp/out.avi
919@end example
920
921test.yuv is a file containing raw YUV planar data. Each frame is composed
922of the Y plane followed by the U and V planes at half vertical and
923horizontal resolution.
924
925@item
926You can output to a raw YUV420P file:
927
928@example
929avconv -i mydivx.avi hugefile.yuv
930@end example
931
932@item
933You can set several input files and output files:
934
935@example
936avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
937@end example
938
939Converts the audio file a.wav and the raw YUV video file a.yuv
940to MPEG file a.mpg.
941
942@item
943You can also do audio and video conversions at the same time:
944
945@example
946avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
947@end example
948
949Converts a.wav to MPEG audio at 22050 Hz sample rate.
950
951@item
952You can encode to several formats at the same time and define a
953mapping from input stream to output streams:
954
955@example
64db1a82 956avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
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957@end example
958
959Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
960file:index' specifies which input stream is used for each output
961stream, in the order of the definition of output streams.
962
963@item
964You can transcode decrypted VOBs:
965
966@example
64db1a82 967avconv -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi
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968@end example
969
970This is a typical DVD ripping example; the input is a VOB file, the
971output an AVI file with MPEG-4 video and MP3 audio. Note that in this
972command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
973GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
974input video. Furthermore, the audio stream is MP3-encoded so you need
975to enable LAME support by passing @code{--enable-libmp3lame} to configure.
976The mapping is particularly useful for DVD transcoding
977to get the desired audio language.
978
979NOTE: To see the supported input formats, use @code{avconv -formats}.
980
981@item
982You can extract images from a video, or create a video from many images:
983
984For extracting images from a video:
985@example
986avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
987@end example
988
989This will extract one video frame per second from the video and will
990output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
991etc. Images will be rescaled to fit the new WxH values.
992
993If you want to extract just a limited number of frames, you can use the
994above command in combination with the -vframes or -t option, or in
995combination with -ss to start extracting from a certain point in time.
996
997For creating a video from many images:
998@example
999avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1000@end example
1001
1002The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1003composed of three digits padded with zeroes to express the sequence
1004number. It is the same syntax supported by the C printf function, but
1005only formats accepting a normal integer are suitable.
1006
1007@item
1008You can put many streams of the same type in the output:
1009
1010@example
92f1940e 1011avconv -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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1012@end example
1013
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1014The resulting output file @file{test12.avi} will contain first four streams from
1015the input file in reverse order.
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1016
1017@end itemize
1018@c man end EXAMPLES
1019
1020@include eval.texi
1021@include encoders.texi
1022@include demuxers.texi
1023@include muxers.texi
1024@include indevs.texi
1025@include outdevs.texi
1026@include protocols.texi
1027@include bitstream_filters.texi
1028@include filters.texi
1029@include metadata.texi
1030
1031@ignore
1032
1033@setfilename avconv
1034@settitle avconv video converter
1035
1036@c man begin SEEALSO
1037avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1038@c man end
1039
1040@c man begin AUTHORS
1041The Libav developers
1042@c man end
1043
1044@end ignore
1045
1046@bye