avconv: move max_frames 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 -slang @var{code}
206Set the ISO 639 language code (3 letters) of the current subtitle stream.
207
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208@item -frames[:stream_specifier] @var{framecount}
209Stop writing to the stream after @var{framecount} frames.
210
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211@end table
212
213@section Video Options
214
215@table @option
216@item -vframes @var{number}
96139b5e 217Set the number of video frames to record. This is an alias for @code{-frames:v}.
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218@item -r @var{fps}
219Set frame rate (Hz value, fraction or abbreviation), (default = 25).
220@item -s @var{size}
221Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
222The following abbreviations are recognized:
223@table @samp
224@item sqcif
225128x96
226@item qcif
227176x144
228@item cif
229352x288
230@item 4cif
231704x576
232@item 16cif
2331408x1152
234@item qqvga
235160x120
236@item qvga
237320x240
238@item vga
239640x480
240@item svga
241800x600
242@item xga
2431024x768
244@item uxga
2451600x1200
246@item qxga
2472048x1536
248@item sxga
2491280x1024
250@item qsxga
2512560x2048
252@item hsxga
2535120x4096
254@item wvga
255852x480
256@item wxga
2571366x768
258@item wsxga
2591600x1024
260@item wuxga
2611920x1200
262@item woxga
2632560x1600
264@item wqsxga
2653200x2048
266@item wquxga
2673840x2400
268@item whsxga
2696400x4096
270@item whuxga
2717680x4800
272@item cga
273320x200
274@item ega
275640x350
276@item hd480
277852x480
278@item hd720
2791280x720
280@item hd1080
2811920x1080
282@end table
283
284@item -aspect @var{aspect}
285Set the video display aspect ratio specified by @var{aspect}.
286
287@var{aspect} can be a floating point number string, or a string of the
288form @var{num}:@var{den}, where @var{num} and @var{den} are the
289numerator and denominator of the aspect ratio. For example "4:3",
290"16:9", "1.3333", and "1.7777" are valid argument values.
291
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292@item -vn
293Disable video recording.
294@item -bt @var{tolerance}
295Set video bitrate tolerance (in bits, default 4000k).
296Has a minimum value of: (target_bitrate/target_framerate).
297In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
298willing to deviate from the target average bitrate value. This is
299not related to min/max bitrate. Lowering tolerance too much has
300an adverse effect on quality.
301@item -maxrate @var{bitrate}
302Set max video bitrate (in bit/s).
303Requires -bufsize to be set.
304@item -minrate @var{bitrate}
305Set min video bitrate (in bit/s).
306Most useful in setting up a CBR encode:
307@example
308avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
309@end example
310It is of little use elsewise.
311@item -bufsize @var{size}
312Set video buffer verifier buffer size (in bits).
313@item -vcodec @var{codec}
92f1940e 314Set the video codec. This is an alias for @code{-codec:v}.
f4ad238c 315@item -same_quant
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316Use same quantizer as source (implies VBR).
317
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318Note that this is NOT SAME QUALITY. Do not use this option unless you know you
319need it.
320
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321@item -pass @var{n}
322Select the pass number (1 or 2). It is used to do two-pass
323video encoding. The statistics of the video are recorded in the first
324pass into a log file (see also the option -passlogfile),
325and in the second pass that log file is used to generate the video
326at the exact requested bitrate.
327On pass 1, you may just deactivate audio and set output to null,
328examples for Windows and Unix:
329@example
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330avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
331avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
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332@end example
333
334@item -passlogfile @var{prefix}
335Set two-pass log file name prefix to @var{prefix}, the default file name
336prefix is ``av2pass''. The complete file name will be
337@file{PREFIX-N.log}, where N is a number specific to the output
338stream.
339
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340@item -vlang @var{code}
341Set the ISO 639 language code (3 letters) of the current video stream.
342
343@item -vf @var{filter_graph}
344@var{filter_graph} is a description of the filter graph to apply to
345the input video.
346Use the option "-filters" to show all the available filters (including
347also sources and sinks).
348
349@end table
350
351@section Advanced Video Options
352
353@table @option
354@item -pix_fmt @var{format}
355Set pixel format. Use 'list' as parameter to show all the supported
356pixel formats.
357@item -sws_flags @var{flags}
358Set SwScaler flags.
359@item -g @var{gop_size}
360Set the group of pictures size.
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361@item -vdt @var{n}
362Discard threshold.
363@item -qscale @var{q}
364Use fixed video quantizer scale (VBR).
365@item -qmin @var{q}
366minimum video quantizer scale (VBR)
367@item -qmax @var{q}
368maximum video quantizer scale (VBR)
369@item -qdiff @var{q}
370maximum difference between the quantizer scales (VBR)
371@item -qblur @var{blur}
372video quantizer scale blur (VBR) (range 0.0 - 1.0)
373@item -qcomp @var{compression}
374video quantizer scale compression (VBR) (default 0.5).
375Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
376
377@item -lmin @var{lambda}
378minimum video lagrange factor (VBR)
379@item -lmax @var{lambda}
380max video lagrange factor (VBR)
381@item -mblmin @var{lambda}
382minimum macroblock quantizer scale (VBR)
383@item -mblmax @var{lambda}
384maximum macroblock quantizer scale (VBR)
385
386These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
387but you may use the QP2LAMBDA constant to easily convert from 'q' units:
388@example
389avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
390@end example
391
392@item -rc_init_cplx @var{complexity}
393initial complexity for single pass encoding
394@item -b_qfactor @var{factor}
395qp factor between P- and B-frames
396@item -i_qfactor @var{factor}
397qp factor between P- and I-frames
398@item -b_qoffset @var{offset}
399qp offset between P- and B-frames
400@item -i_qoffset @var{offset}
401qp offset between P- and I-frames
402@item -rc_eq @var{equation}
403Set rate control equation (see section "Expression Evaluation")
404(default = @code{tex^qComp}).
405
406When computing the rate control equation expression, besides the
407standard functions defined in the section "Expression Evaluation", the
408following functions are available:
409@table @var
410@item bits2qp(bits)
411@item qp2bits(qp)
412@end table
413
414and the following constants are available:
415@table @var
416@item iTex
417@item pTex
418@item tex
419@item mv
420@item fCode
421@item iCount
422@item mcVar
423@item var
424@item isI
425@item isP
426@item isB
427@item avgQP
428@item qComp
429@item avgIITex
430@item avgPITex
431@item avgPPTex
432@item avgBPTex
433@item avgTex
434@end table
435
436@item -rc_override @var{override}
437rate control override for specific intervals
438@item -me_method @var{method}
439Set motion estimation method to @var{method}.
440Available methods are (from lowest to best quality):
441@table @samp
442@item zero
443Try just the (0, 0) vector.
444@item phods
445@item log
446@item x1
447@item hex
448@item umh
449@item epzs
450(default method)
451@item full
452exhaustive search (slow and marginally better than epzs)
453@end table
454
455@item -dct_algo @var{algo}
456Set DCT algorithm to @var{algo}. Available values are:
457@table @samp
458@item 0
459FF_DCT_AUTO (default)
460@item 1
461FF_DCT_FASTINT
462@item 2
463FF_DCT_INT
464@item 3
465FF_DCT_MMX
466@item 4
467FF_DCT_MLIB
468@item 5
469FF_DCT_ALTIVEC
470@end table
471
472@item -idct_algo @var{algo}
473Set IDCT algorithm to @var{algo}. Available values are:
474@table @samp
475@item 0
476FF_IDCT_AUTO (default)
477@item 1
478FF_IDCT_INT
479@item 2
480FF_IDCT_SIMPLE
481@item 3
482FF_IDCT_SIMPLEMMX
483@item 4
484FF_IDCT_LIBMPEG2MMX
485@item 5
486FF_IDCT_PS2
487@item 6
488FF_IDCT_MLIB
489@item 7
490FF_IDCT_ARM
491@item 8
492FF_IDCT_ALTIVEC
493@item 9
494FF_IDCT_SH4
495@item 10
496FF_IDCT_SIMPLEARM
497@end table
498
499@item -er @var{n}
500Set error resilience to @var{n}.
501@table @samp
502@item 1
503FF_ER_CAREFUL (default)
504@item 2
505FF_ER_COMPLIANT
506@item 3
507FF_ER_AGGRESSIVE
508@item 4
509FF_ER_VERY_AGGRESSIVE
510@end table
511
512@item -ec @var{bit_mask}
513Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
514the following values:
515@table @samp
516@item 1
517FF_EC_GUESS_MVS (default = enabled)
518@item 2
519FF_EC_DEBLOCK (default = enabled)
520@end table
521
522@item -bf @var{frames}
523Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
524@item -mbd @var{mode}
525macroblock decision
526@table @samp
527@item 0
528FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
529@item 1
530FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
531@item 2
532FF_MB_DECISION_RD: rate distortion
533@end table
534
535@item -4mv
536Use four motion vector by macroblock (MPEG-4 only).
537@item -part
538Use data partitioning (MPEG-4 only).
539@item -bug @var{param}
540Work around encoder bugs that are not auto-detected.
541@item -strict @var{strictness}
542How strictly to follow the standards.
543@item -aic
544Enable Advanced intra coding (h263+).
545@item -umv
546Enable Unlimited Motion Vector (h263+)
547
548@item -deinterlace
549Deinterlace pictures.
550@item -ilme
551Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
552Use this option if your input file is interlaced and you want
553to keep the interlaced format for minimum losses.
554The alternative is to deinterlace the input stream with
555@option{-deinterlace}, but deinterlacing introduces losses.
556@item -psnr
557Calculate PSNR of compressed frames.
558@item -vstats
559Dump video coding statistics to @file{vstats_HHMMSS.log}.
560@item -vstats_file @var{file}
561Dump video coding statistics to @var{file}.
562@item -top @var{n}
563top=1/bottom=0/auto=-1 field first
564@item -dc @var{precision}
565Intra_dc_precision.
566@item -vtag @var{fourcc/tag}
567Force video tag/fourcc.
568@item -qphist
569Show QP histogram.
570@item -vbsf @var{bitstream_filter}
571Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
572@example
92f1940e 573avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
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574@end example
575@item -force_key_frames @var{time}[,@var{time}...]
576Force key frames at the specified timestamps, more precisely at the first
577frames after each specified time.
578This option can be useful to ensure that a seek point is present at a
579chapter mark or any other designated place in the output file.
580The timestamps must be specified in ascending order.
581@end table
582
583@section Audio Options
584
585@table @option
586@item -aframes @var{number}
96139b5e 587Set the number of audio frames to record. This is an alias for @code{-frames:a}.
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588@item -ar @var{freq}
589Set the audio sampling frequency. For output streams it is set by
590default to the frequency of the corresponding input stream. For input
591streams this option only makes sense for audio grabbing devices and raw
592demuxers and is mapped to the corresponding demuxer options.
593@item -aq @var{q}
594Set the audio quality (codec-specific, VBR).
595@item -ac @var{channels}
596Set the number of audio channels. For output streams it is set by
597default to the number of input audio channels. For input streams
598this option only makes sense for audio grabbing devices and raw demuxers
599and is mapped to the corresponding demuxer options.
600@item -an
601Disable audio recording.
602@item -acodec @var{codec}
92f1940e 603Set the audio codec. This is an alias for @code{-codec:a}.
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604@item -alang @var{code}
605Set the ISO 639 language code (3 letters) of the current audio stream.
606@end table
607
608@section Advanced Audio options:
609
610@table @option
611@item -atag @var{fourcc/tag}
612Force audio tag/fourcc.
613@item -audio_service_type @var{type}
614Set the type of service that the audio stream contains.
615@table @option
616@item ma
617Main Audio Service (default)
618@item ef
619Effects
620@item vi
621Visually Impaired
622@item hi
623Hearing Impaired
624@item di
625Dialogue
626@item co
627Commentary
628@item em
629Emergency
630@item vo
631Voice Over
632@item ka
633Karaoke
634@end table
635@item -absf @var{bitstream_filter}
636Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
637@end table
638
639@section Subtitle options:
640
641@table @option
642@item -scodec @var{codec}
92f1940e 643Set the subtitle codec. This is an alias for @code{-codec:s}.
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644@item -slang @var{code}
645Set the ISO 639 language code (3 letters) of the current subtitle stream.
646@item -sn
647Disable subtitle recording.
648@item -sbsf @var{bitstream_filter}
649Bitstream filters available are "mov2textsub", "text2movsub".
650@example
92f1940e 651avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
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652@end example
653@end table
654
655@section Audio/Video grab options
656
657@table @option
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658@item -isync
659Synchronize read on input.
660@end table
661
662@section Advanced options
663
664@table @option
8d2e4a7e 665@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 666
8d2e4a7e 667Designate one or more input streams as a source for the output file. Each input
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668stream is identified by the input file index @var{input_file_id} and
669the input stream index @var{input_stream_id} within the input
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670file. Both indices start at 0. If specified,
671@var{sync_file_id}:@var{sync_stream_id} sets which input stream
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672is used as a presentation sync reference.
673
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674If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
675subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
676of this type. Same for @var{sync_stream_type}.
677
678@var{input_stream_id} may be omitted, in which case all streams of the given
679type are mapped (or all streams in the file, if no type is specified).
680
3d4f0dab 681The first @code{-map} option on the command line specifies the
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682source for output stream 0, the second @code{-map} option specifies
683the source for output stream 1, etc.
684
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685A @code{-} character before the stream identifier creates a "negative" mapping.
686It disables matching streams from already created mappings.
687
688For example, to map ALL streams from the first input file to output
689@example
f5bae2c6 690avconv -i INPUT -map 0 output
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691@end example
692
6291d7e4 693For example, if you have two audio streams in the first input file,
8d2e4a7e 694these streams are identified by "0:0" and "0:1". You can use
3d4f0dab 695@code{-map} to select which streams to place in an output file. For
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696example:
697@example
8d2e4a7e 698avconv -i INPUT -map 0:1 out.wav
6291d7e4 699@end example
8d2e4a7e 700will map the input stream in @file{INPUT} identified by "0:1" to
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701the (single) output stream in @file{out.wav}.
702
703For example, to select the stream with index 2 from input file
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704@file{a.mov} (specified by the identifier "0:2"), and stream with
705index 6 from input @file{b.mov} (specified by the identifier "1:6"),
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706and copy them to the output file @file{out.mov}:
707@example
92f1940e 708avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
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709@end example
710
711To select all video and the third audio stream from an input file:
712@example
713avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
714@end example
715
716To map all the streams except the second audio, use negative mappings
717@example
718avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
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719@end example
720
3d4f0dab 721Note that using this option disables the default mappings for this output file.
6291d7e4 722
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723@item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
724Set metadata information of the next output file from @var{infile}. Note that
725those are file indices (zero-based), not filenames.
726Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
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727(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
728per-(p)rogram. All metadata specifiers other than global must be followed by the
e6e6060c 729stream/chapter/program index. If metadata specifier is omitted, it defaults to
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730global.
731
e6e6060c 732By default, global metadata is copied from the first input file,
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733per-stream and per-chapter metadata is copied along with streams/chapters. These
734default mappings are disabled by creating any mapping of the relevant type. A negative
735file index can be used to create a dummy mapping that just disables automatic copying.
736
737For example to copy metadata from the first stream of the input file to global metadata
738of the output file:
739@example
e6e6060c 740avconv -i in.ogg -map_metadata 0:s:0 out.mp3
6291d7e4 741@end example
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742@item -map_chapters @var{input_file_index}
743Copy chapters from input file with index @var{input_file_index} to the next
744output file. If no chapter mapping is specified, then chapters are copied from
745the first input file with at least one chapter. Use a negative file index to
746disable any chapter copying.
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747@item -debug
748Print specific debug info.
749@item -benchmark
750Show benchmarking information at the end of an encode.
751Shows CPU time used and maximum memory consumption.
752Maximum memory consumption is not supported on all systems,
753it will usually display as 0 if not supported.
754@item -dump
755Dump each input packet.
756@item -hex
757When dumping packets, also dump the payload.
758@item -bitexact
759Only use bit exact algorithms (for codec testing).
760@item -ps @var{size}
761Set RTP payload size in bytes.
762@item -re
763Read input at native frame rate. Mainly used to simulate a grab device.
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764@item -threads @var{count}
765Thread count.
766@item -vsync @var{parameter}
767Video sync method.
768
769@table @option
770@item 0
771Each frame is passed with its timestamp from the demuxer to the muxer.
772@item 1
773Frames will be duplicated and dropped to achieve exactly the requested
774constant framerate.
775@item 2
776Frames are passed through with their timestamp or dropped so as to
777prevent 2 frames from having the same timestamp.
778@item -1
779Chooses between 1 and 2 depending on muxer capabilities. This is the
780default method.
781@end table
782
783With -map you can select from which stream the timestamps should be
784taken. You can leave either video or audio unchanged and sync the
785remaining stream(s) to the unchanged one.
786
787@item -async @var{samples_per_second}
788Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
789the parameter is the maximum samples per second by which the audio is changed.
790-async 1 is a special case where only the start of the audio stream is corrected
791without any later correction.
792@item -copyts
793Copy timestamps from input to output.
794@item -copytb
795Copy input stream time base from input to output when stream copying.
796@item -shortest
797Finish encoding when the shortest input stream ends.
798@item -dts_delta_threshold
799Timestamp discontinuity delta threshold.
800@item -muxdelay @var{seconds}
801Set the maximum demux-decode delay.
802@item -muxpreload @var{seconds}
803Set the initial demux-decode delay.
804@item -streamid @var{output-stream-index}:@var{new-value}
805Assign a new stream-id value to an output stream. This option should be
806specified prior to the output filename to which it applies.
807For the situation where multiple output files exist, a streamid
808may be reassigned to a different value.
809
810For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
811an output mpegts file:
812@example
813avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
814@end example
815@end table
7478ab5a 816@c man end OPTIONS
6291d7e4 817
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818@chapter Tips
819@c man begin TIPS
820
821@itemize
822@item
823For streaming at very low bitrate application, use a low frame rate
824and a small GOP size. This is especially true for RealVideo where
825the Linux player does not seem to be very fast, so it can miss
826frames. An example is:
827
828@example
829avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
830@end example
831
832@item
833The parameter 'q' which is displayed while encoding is the current
834quantizer. The value 1 indicates that a very good quality could
835be achieved. The value 31 indicates the worst quality. If q=31 appears
836too often, it means that the encoder cannot compress enough to meet
837your bitrate. You must either increase the bitrate, decrease the
838frame rate or decrease the frame size.
839
840@item
841If your computer is not fast enough, you can speed up the
842compression at the expense of the compression ratio. You can use
843'-me zero' to speed up motion estimation, and '-intra' to disable
844motion estimation completely (you have only I-frames, which means it
845is about as good as JPEG compression).
846
847@item
848To have very low audio bitrates, reduce the sampling frequency
849(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
850
851@item
852To have a constant quality (but a variable bitrate), use the option
853'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
854quality).
855
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856@end itemize
857@c man end TIPS
858
859@chapter Examples
860@c man begin EXAMPLES
861
862@section Video and Audio grabbing
863
864If you specify the input format and device then avconv can grab video
865and audio directly.
866
867@example
868avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
869@end example
870
871Note that you must activate the right video source and channel before
872launching avconv with any TV viewer such as
873@uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
874have to set the audio recording levels correctly with a
875standard mixer.
876
877@section X11 grabbing
878
879Grab the X11 display with avconv via
880
881@example
882avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
883@end example
884
8850.0 is display.screen number of your X11 server, same as
886the DISPLAY environment variable.
887
888@example
889avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
890@end example
891
8920.0 is display.screen number of your X11 server, same as the DISPLAY environment
893variable. 10 is the x-offset and 20 the y-offset for the grabbing.
894
895@section Video and Audio file format conversion
896
897Any supported file format and protocol can serve as input to avconv:
898
899Examples:
900@itemize
901@item
902You can use YUV files as input:
903
904@example
905avconv -i /tmp/test%d.Y /tmp/out.mpg
906@end example
907
908It will use the files:
909@example
910/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
911/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
912@end example
913
914The Y files use twice the resolution of the U and V files. They are
915raw files, without header. They can be generated by all decent video
916decoders. You must specify the size of the image with the @option{-s} option
917if avconv cannot guess it.
918
919@item
920You can input from a raw YUV420P file:
921
922@example
923avconv -i /tmp/test.yuv /tmp/out.avi
924@end example
925
926test.yuv is a file containing raw YUV planar data. Each frame is composed
927of the Y plane followed by the U and V planes at half vertical and
928horizontal resolution.
929
930@item
931You can output to a raw YUV420P file:
932
933@example
934avconv -i mydivx.avi hugefile.yuv
935@end example
936
937@item
938You can set several input files and output files:
939
940@example
941avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
942@end example
943
944Converts the audio file a.wav and the raw YUV video file a.yuv
945to MPEG file a.mpg.
946
947@item
948You can also do audio and video conversions at the same time:
949
950@example
951avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
952@end example
953
954Converts a.wav to MPEG audio at 22050 Hz sample rate.
955
956@item
957You can encode to several formats at the same time and define a
958mapping from input stream to output streams:
959
960@example
64db1a82 961avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
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962@end example
963
964Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
965file:index' specifies which input stream is used for each output
966stream, in the order of the definition of output streams.
967
968@item
969You can transcode decrypted VOBs:
970
971@example
64db1a82 972avconv -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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973@end example
974
975This is a typical DVD ripping example; the input is a VOB file, the
976output an AVI file with MPEG-4 video and MP3 audio. Note that in this
977command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
978GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
979input video. Furthermore, the audio stream is MP3-encoded so you need
980to enable LAME support by passing @code{--enable-libmp3lame} to configure.
981The mapping is particularly useful for DVD transcoding
982to get the desired audio language.
983
984NOTE: To see the supported input formats, use @code{avconv -formats}.
985
986@item
987You can extract images from a video, or create a video from many images:
988
989For extracting images from a video:
990@example
991avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
992@end example
993
994This will extract one video frame per second from the video and will
995output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
996etc. Images will be rescaled to fit the new WxH values.
997
998If you want to extract just a limited number of frames, you can use the
999above command in combination with the -vframes or -t option, or in
1000combination with -ss to start extracting from a certain point in time.
1001
1002For creating a video from many images:
1003@example
1004avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1005@end example
1006
1007The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1008composed of three digits padded with zeroes to express the sequence
1009number. It is the same syntax supported by the C printf function, but
1010only formats accepting a normal integer are suitable.
1011
1012@item
1013You can put many streams of the same type in the output:
1014
1015@example
92f1940e 1016avconv -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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1017@end example
1018
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1019The resulting output file @file{test12.avi} will contain first four streams from
1020the input file in reverse order.
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1021
1022@end itemize
1023@c man end EXAMPLES
1024
1025@include eval.texi
1026@include encoders.texi
1027@include demuxers.texi
1028@include muxers.texi
1029@include indevs.texi
1030@include outdevs.texi
1031@include protocols.texi
1032@include bitstream_filters.texi
1033@include filters.texi
1034@include metadata.texi
1035
1036@ignore
1037
1038@setfilename avconv
1039@settitle avconv video converter
1040
1041@c man begin SEEALSO
1042avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1043@c man end
1044
1045@c man begin AUTHORS
1046The Libav developers
1047@c man end
1048
1049@end ignore
1050
1051@bye