1b9a7929d63cbea7e090923be9336db757d369fe
[libav.git] / doc / avconv.texi
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
14 The generic syntax is:
15
16 @example
17 @c man begin SYNOPSIS
18 avconv [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
19 @c man end
20 @end example
21
22 @chapter Description
23 @c man begin DESCRIPTION
24
25 avconv is a very fast video and audio converter that can also grab from
26 a live audio/video source. It can also convert between arbitrary sample
27 rates and resize video on the fly with a high quality polyphase filter.
28
29 The command line interface is designed to be intuitive, in the sense
30 that avconv tries to figure out all parameters that can possibly be
31 derived automatically. You usually only have to specify the target
32 bitrate you want.
33
34 As a general rule, options are applied to the next specified
35 file. Therefore, order is important, and you can have the same
36 option on the command line multiple times. Each occurrence is
37 then applied to the next input or output file.
38
39 @itemize
40 @item
41 To set the video bitrate of the output file to 64kbit/s:
42 @example
43 avconv -i input.avi -b 64k output.avi
44 @end example
45
46 @item
47 To force the frame rate of the output file to 24 fps:
48 @example
49 avconv -i input.avi -r 24 output.avi
50 @end example
51
52 @item
53 To force the frame rate of the input file (valid for raw formats only)
54 to 1 fps and the frame rate of the output file to 24 fps:
55 @example
56 avconv -r 1 -i input.m2v -r 24 output.avi
57 @end example
58 @end itemize
59
60 The format option may be needed for raw input files.
61
62 By default avconv tries to convert as losslessly as possible: It
63 uses the same audio and video parameters for the outputs as the one
64 specified for the inputs.
65
66 @c man end DESCRIPTION
67
68 @chapter Stream selection
69 @c man begin STREAM SELECTION
70
71 By default avconv tries to pick the "best" stream of each type present in input
72 files and add them to each output file. For video, this means the highest
73 resolution, for audio the highest channel count. For subtitle it's simply the
74 first subtitle stream.
75
76 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
77 full manual control, use the @code{-map} option, which disables the defaults just
78 described.
79
80 @c man end STREAM SELECTION
81
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}
92 Force format.
93
94 @item -i @var{filename}
95 input file name
96
97 @item -y
98 Overwrite output files.
99
100 @item -c[:@var{stream_type}][:@var{stream_index}] @var{codec}
101 @item -codec[:@var{stream_type}][:@var{stream_index}] @var{codec}
102 Select an encoder (when used before an output file) or a decoder (when used
103 before an input file) for one or more streams. @var{codec} is the name of a
104 decoder/encoder or a special value @code{copy} (output only) to indicate that
105 the stream is not to be reencoded.
106
107 @var{stream_type} may be 'v' for video, 'a' for audio, 's' for subtitle and 'd'
108 for 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
110 type. If @var{stream_index} is omitted, this option applies to all streams of
111 the given type or all streams of any type if @var{stream_type} is missing as
112 well (note that this only makes sense when all streams are of the same type or
113 @var{codec} is @code{copy}).
114
115 For example
116 @example
117 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
118 @end example
119 encodes all video streams with libx264 and copies all audio streams.
120
121 For each stream, the last matching @code{c} option is applied, so
122 @example
123 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
124 @end example
125 will copy all the streams except the second video, which will be encoded with
126 libx264, and the 138th audio, which will be encoded with libvorbis.
127
128 @item -t @var{duration}
129 Restrict the transcoded/captured video sequence
130 to the duration specified in seconds.
131 @code{hh:mm:ss[.xxx]} syntax is also supported.
132
133 @item -fs @var{limit_size}
134 Set the file size limit.
135
136 @item -ss @var{position}
137 When 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),
139 decodes but discards input until the timestamps reach @var{position}. This is
140 slower, but more accurate.
141
142 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
143
144 @item -itsoffset @var{offset}
145 Set the input time offset in seconds.
146 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
147 The offset is added to the timestamps of the input files.
148 Specifying a positive offset means that the corresponding
149 streams are delayed by 'offset' seconds.
150
151 @item -timestamp @var{time}
152 Set the recording timestamp in the container.
153 The syntax for @var{time} is:
154 @example
155 now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
156 @end example
157 If the value is "now" it takes the current time.
158 Time is local time unless 'Z' or 'z' is appended, in which case it is
159 interpreted as UTC.
160 If the year-month-day part is not specified it takes the current
161 year-month-day.
162
163 @item -metadata[:metadata_specifier] @var{key}=@var{value}
164 Set a metadata key/value pair.
165
166 An optional @var{metadata_specifier} may be given to set metadata
167 on streams or chapters. See @code{-map_metadata} documentation for
168 details.
169
170 This option overrides metadata set with @code{-map_metadata}. It is
171 also possible to delete metadata by using an empty value.
172
173 For example, for setting the title in the output file:
174 @example
175 avconv -i in.avi -metadata title="my title" out.flv
176 @end example
177
178 To set the language of the second stream:
179 @example
180 avconv -i INPUT -metadata:s:1 language=eng OUTPUT
181 @end example
182
183 @item -v @var{number}
184 Set the logging verbosity level.
185
186 @item -target @var{type}
187 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
188 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
189 buffer sizes) are then set automatically. You can just type:
190
191 @example
192 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
193 @end example
194
195 Nevertheless you can specify additional options as long as you know
196 they do not conflict with the standard, as in:
197
198 @example
199 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
200 @end example
201
202 @item -dframes @var{number}
203 Set the number of data frames to record. This is an alias for @code{-frames:d}.
204
205 @item -slang @var{code}
206 Set the ISO 639 language code (3 letters) of the current subtitle stream.
207
208 @item -frames[:stream_specifier] @var{framecount}
209 Stop writing to the stream after @var{framecount} frames.
210
211 @end table
212
213 @section Video Options
214
215 @table @option
216 @item -vframes @var{number}
217 Set the number of video frames to record. This is an alias for @code{-frames:v}.
218 @item -r @var{fps}
219 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
220 @item -s @var{size}
221 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
222 The following abbreviations are recognized:
223 @table @samp
224 @item sqcif
225 128x96
226 @item qcif
227 176x144
228 @item cif
229 352x288
230 @item 4cif
231 704x576
232 @item 16cif
233 1408x1152
234 @item qqvga
235 160x120
236 @item qvga
237 320x240
238 @item vga
239 640x480
240 @item svga
241 800x600
242 @item xga
243 1024x768
244 @item uxga
245 1600x1200
246 @item qxga
247 2048x1536
248 @item sxga
249 1280x1024
250 @item qsxga
251 2560x2048
252 @item hsxga
253 5120x4096
254 @item wvga
255 852x480
256 @item wxga
257 1366x768
258 @item wsxga
259 1600x1024
260 @item wuxga
261 1920x1200
262 @item woxga
263 2560x1600
264 @item wqsxga
265 3200x2048
266 @item wquxga
267 3840x2400
268 @item whsxga
269 6400x4096
270 @item whuxga
271 7680x4800
272 @item cga
273 320x200
274 @item ega
275 640x350
276 @item hd480
277 852x480
278 @item hd720
279 1280x720
280 @item hd1080
281 1920x1080
282 @end table
283
284 @item -aspect @var{aspect}
285 Set 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
288 form @var{num}:@var{den}, where @var{num} and @var{den} are the
289 numerator and denominator of the aspect ratio. For example "4:3",
290 "16:9", "1.3333", and "1.7777" are valid argument values.
291
292 @item -vn
293 Disable video recording.
294 @item -bt @var{tolerance}
295 Set video bitrate tolerance (in bits, default 4000k).
296 Has a minimum value of: (target_bitrate/target_framerate).
297 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
298 willing to deviate from the target average bitrate value. This is
299 not related to min/max bitrate. Lowering tolerance too much has
300 an adverse effect on quality.
301 @item -maxrate @var{bitrate}
302 Set max video bitrate (in bit/s).
303 Requires -bufsize to be set.
304 @item -minrate @var{bitrate}
305 Set min video bitrate (in bit/s).
306 Most useful in setting up a CBR encode:
307 @example
308 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
309 @end example
310 It is of little use elsewise.
311 @item -bufsize @var{size}
312 Set video buffer verifier buffer size (in bits).
313 @item -vcodec @var{codec}
314 Set the video codec. This is an alias for @code{-codec:v}.
315 @item -same_quant
316 Use same quantizer as source (implies VBR).
317
318 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
319 need it.
320
321 @item -pass @var{n}
322 Select the pass number (1 or 2). It is used to do two-pass
323 video encoding. The statistics of the video are recorded in the first
324 pass into a log file (see also the option -passlogfile),
325 and in the second pass that log file is used to generate the video
326 at the exact requested bitrate.
327 On pass 1, you may just deactivate audio and set output to null,
328 examples for Windows and Unix:
329 @example
330 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
331 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
332 @end example
333
334 @item -passlogfile @var{prefix}
335 Set two-pass log file name prefix to @var{prefix}, the default file name
336 prefix is ``av2pass''. The complete file name will be
337 @file{PREFIX-N.log}, where N is a number specific to the output
338 stream.
339
340 @item -vlang @var{code}
341 Set 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
345 the input video.
346 Use the option "-filters" to show all the available filters (including
347 also sources and sinks).
348
349 @end table
350
351 @section Advanced Video Options
352
353 @table @option
354 @item -pix_fmt @var{format}
355 Set pixel format. Use 'list' as parameter to show all the supported
356 pixel formats.
357 @item -sws_flags @var{flags}
358 Set SwScaler flags.
359 @item -g @var{gop_size}
360 Set the group of pictures size.
361 @item -vdt @var{n}
362 Discard threshold.
363 @item -qscale @var{q}
364 Use fixed video quantizer scale (VBR).
365 @item -qmin @var{q}
366 minimum video quantizer scale (VBR)
367 @item -qmax @var{q}
368 maximum video quantizer scale (VBR)
369 @item -qdiff @var{q}
370 maximum difference between the quantizer scales (VBR)
371 @item -qblur @var{blur}
372 video quantizer scale blur (VBR) (range 0.0 - 1.0)
373 @item -qcomp @var{compression}
374 video quantizer scale compression (VBR) (default 0.5).
375 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
376
377 @item -lmin @var{lambda}
378 minimum video lagrange factor (VBR)
379 @item -lmax @var{lambda}
380 max video lagrange factor (VBR)
381 @item -mblmin @var{lambda}
382 minimum macroblock quantizer scale (VBR)
383 @item -mblmax @var{lambda}
384 maximum macroblock quantizer scale (VBR)
385
386 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
387 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
388 @example
389 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
390 @end example
391
392 @item -rc_init_cplx @var{complexity}
393 initial complexity for single pass encoding
394 @item -b_qfactor @var{factor}
395 qp factor between P- and B-frames
396 @item -i_qfactor @var{factor}
397 qp factor between P- and I-frames
398 @item -b_qoffset @var{offset}
399 qp offset between P- and B-frames
400 @item -i_qoffset @var{offset}
401 qp offset between P- and I-frames
402 @item -rc_eq @var{equation}
403 Set rate control equation (see section "Expression Evaluation")
404 (default = @code{tex^qComp}).
405
406 When computing the rate control equation expression, besides the
407 standard functions defined in the section "Expression Evaluation", the
408 following functions are available:
409 @table @var
410 @item bits2qp(bits)
411 @item qp2bits(qp)
412 @end table
413
414 and 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}
437 rate control override for specific intervals
438 @item -me_method @var{method}
439 Set motion estimation method to @var{method}.
440 Available methods are (from lowest to best quality):
441 @table @samp
442 @item zero
443 Try 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
452 exhaustive search (slow and marginally better than epzs)
453 @end table
454
455 @item -dct_algo @var{algo}
456 Set DCT algorithm to @var{algo}. Available values are:
457 @table @samp
458 @item 0
459 FF_DCT_AUTO (default)
460 @item 1
461 FF_DCT_FASTINT
462 @item 2
463 FF_DCT_INT
464 @item 3
465 FF_DCT_MMX
466 @item 4
467 FF_DCT_MLIB
468 @item 5
469 FF_DCT_ALTIVEC
470 @end table
471
472 @item -idct_algo @var{algo}
473 Set IDCT algorithm to @var{algo}. Available values are:
474 @table @samp
475 @item 0
476 FF_IDCT_AUTO (default)
477 @item 1
478 FF_IDCT_INT
479 @item 2
480 FF_IDCT_SIMPLE
481 @item 3
482 FF_IDCT_SIMPLEMMX
483 @item 4
484 FF_IDCT_LIBMPEG2MMX
485 @item 5
486 FF_IDCT_PS2
487 @item 6
488 FF_IDCT_MLIB
489 @item 7
490 FF_IDCT_ARM
491 @item 8
492 FF_IDCT_ALTIVEC
493 @item 9
494 FF_IDCT_SH4
495 @item 10
496 FF_IDCT_SIMPLEARM
497 @end table
498
499 @item -er @var{n}
500 Set error resilience to @var{n}.
501 @table @samp
502 @item 1
503 FF_ER_CAREFUL (default)
504 @item 2
505 FF_ER_COMPLIANT
506 @item 3
507 FF_ER_AGGRESSIVE
508 @item 4
509 FF_ER_VERY_AGGRESSIVE
510 @end table
511
512 @item -ec @var{bit_mask}
513 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
514 the following values:
515 @table @samp
516 @item 1
517 FF_EC_GUESS_MVS (default = enabled)
518 @item 2
519 FF_EC_DEBLOCK (default = enabled)
520 @end table
521
522 @item -bf @var{frames}
523 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
524 @item -mbd @var{mode}
525 macroblock decision
526 @table @samp
527 @item 0
528 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
529 @item 1
530 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
531 @item 2
532 FF_MB_DECISION_RD: rate distortion
533 @end table
534
535 @item -4mv
536 Use four motion vector by macroblock (MPEG-4 only).
537 @item -part
538 Use data partitioning (MPEG-4 only).
539 @item -bug @var{param}
540 Work around encoder bugs that are not auto-detected.
541 @item -strict @var{strictness}
542 How strictly to follow the standards.
543 @item -aic
544 Enable Advanced intra coding (h263+).
545 @item -umv
546 Enable Unlimited Motion Vector (h263+)
547
548 @item -deinterlace
549 Deinterlace pictures.
550 @item -ilme
551 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
552 Use this option if your input file is interlaced and you want
553 to keep the interlaced format for minimum losses.
554 The alternative is to deinterlace the input stream with
555 @option{-deinterlace}, but deinterlacing introduces losses.
556 @item -psnr
557 Calculate PSNR of compressed frames.
558 @item -vstats
559 Dump video coding statistics to @file{vstats_HHMMSS.log}.
560 @item -vstats_file @var{file}
561 Dump video coding statistics to @var{file}.
562 @item -top @var{n}
563 top=1/bottom=0/auto=-1 field first
564 @item -dc @var{precision}
565 Intra_dc_precision.
566 @item -vtag @var{fourcc/tag}
567 Force video tag/fourcc.
568 @item -qphist
569 Show QP histogram.
570 @item -force_key_frames @var{time}[,@var{time}...]
571 Force key frames at the specified timestamps, more precisely at the first
572 frames after each specified time.
573 This option can be useful to ensure that a seek point is present at a
574 chapter mark or any other designated place in the output file.
575 The timestamps must be specified in ascending order.
576 @end table
577
578 @section Audio Options
579
580 @table @option
581 @item -aframes @var{number}
582 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
583 @item -ar @var{freq}
584 Set the audio sampling frequency. For output streams it is set by
585 default to the frequency of the corresponding input stream. For input
586 streams this option only makes sense for audio grabbing devices and raw
587 demuxers and is mapped to the corresponding demuxer options.
588 @item -aq @var{q}
589 Set the audio quality (codec-specific, VBR).
590 @item -ac @var{channels}
591 Set the number of audio channels. For output streams it is set by
592 default to the number of input audio channels. For input streams
593 this option only makes sense for audio grabbing devices and raw demuxers
594 and is mapped to the corresponding demuxer options.
595 @item -an
596 Disable audio recording.
597 @item -acodec @var{codec}
598 Set the audio codec. This is an alias for @code{-codec:a}.
599 @item -alang @var{code}
600 Set the ISO 639 language code (3 letters) of the current audio stream.
601 @end table
602
603 @section Advanced Audio options:
604
605 @table @option
606 @item -atag @var{fourcc/tag}
607 Force audio tag/fourcc.
608 @item -audio_service_type @var{type}
609 Set the type of service that the audio stream contains.
610 @table @option
611 @item ma
612 Main Audio Service (default)
613 @item ef
614 Effects
615 @item vi
616 Visually Impaired
617 @item hi
618 Hearing Impaired
619 @item di
620 Dialogue
621 @item co
622 Commentary
623 @item em
624 Emergency
625 @item vo
626 Voice Over
627 @item ka
628 Karaoke
629 @end table
630 @end table
631
632 @section Subtitle options:
633
634 @table @option
635 @item -scodec @var{codec}
636 Set the subtitle codec. This is an alias for @code{-codec:s}.
637 @item -slang @var{code}
638 Set the ISO 639 language code (3 letters) of the current subtitle stream.
639 @item -sn
640 Disable subtitle recording.
641 @end table
642
643 @section Audio/Video grab options
644
645 @table @option
646 @item -isync
647 Synchronize read on input.
648 @end table
649
650 @section Advanced options
651
652 @table @option
653 @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}]]
654
655 Designate one or more input streams as a source for the output file. Each input
656 stream is identified by the input file index @var{input_file_id} and
657 the input stream index @var{input_stream_id} within the input
658 file. Both indices start at 0. If specified,
659 @var{sync_file_id}:@var{sync_stream_id} sets which input stream
660 is used as a presentation sync reference.
661
662 If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
663 subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
664 of this type. Same for @var{sync_stream_type}.
665
666 @var{input_stream_id} may be omitted, in which case all streams of the given
667 type are mapped (or all streams in the file, if no type is specified).
668
669 The first @code{-map} option on the command line specifies the
670 source for output stream 0, the second @code{-map} option specifies
671 the source for output stream 1, etc.
672
673 A @code{-} character before the stream identifier creates a "negative" mapping.
674 It disables matching streams from already created mappings.
675
676 For example, to map ALL streams from the first input file to output
677 @example
678 avconv -i INPUT -map 0 output
679 @end example
680
681 For example, if you have two audio streams in the first input file,
682 these streams are identified by "0:0" and "0:1". You can use
683 @code{-map} to select which streams to place in an output file. For
684 example:
685 @example
686 avconv -i INPUT -map 0:1 out.wav
687 @end example
688 will map the input stream in @file{INPUT} identified by "0:1" to
689 the (single) output stream in @file{out.wav}.
690
691 For example, to select the stream with index 2 from input file
692 @file{a.mov} (specified by the identifier "0:2"), and stream with
693 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
694 and copy them to the output file @file{out.mov}:
695 @example
696 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
697 @end example
698
699 To select all video and the third audio stream from an input file:
700 @example
701 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
702 @end example
703
704 To map all the streams except the second audio, use negative mappings
705 @example
706 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
707 @end example
708
709 Note that using this option disables the default mappings for this output file.
710
711 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
712 Set metadata information of the next output file from @var{infile}. Note that
713 those are file indices (zero-based), not filenames.
714 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
715 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
716 per-(p)rogram. All metadata specifiers other than global must be followed by the
717 stream/chapter/program index. If metadata specifier is omitted, it defaults to
718 global.
719
720 By default, global metadata is copied from the first input file,
721 per-stream and per-chapter metadata is copied along with streams/chapters. These
722 default mappings are disabled by creating any mapping of the relevant type. A negative
723 file index can be used to create a dummy mapping that just disables automatic copying.
724
725 For example to copy metadata from the first stream of the input file to global metadata
726 of the output file:
727 @example
728 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
729 @end example
730 @item -map_chapters @var{input_file_index}
731 Copy chapters from input file with index @var{input_file_index} to the next
732 output file. If no chapter mapping is specified, then chapters are copied from
733 the first input file with at least one chapter. Use a negative file index to
734 disable any chapter copying.
735 @item -debug
736 Print specific debug info.
737 @item -benchmark
738 Show benchmarking information at the end of an encode.
739 Shows CPU time used and maximum memory consumption.
740 Maximum memory consumption is not supported on all systems,
741 it will usually display as 0 if not supported.
742 @item -dump
743 Dump each input packet.
744 @item -hex
745 When dumping packets, also dump the payload.
746 @item -bitexact
747 Only use bit exact algorithms (for codec testing).
748 @item -ps @var{size}
749 Set RTP payload size in bytes.
750 @item -re
751 Read input at native frame rate. Mainly used to simulate a grab device.
752 @item -threads @var{count}
753 Thread count.
754 @item -vsync @var{parameter}
755 Video sync method.
756
757 @table @option
758 @item 0
759 Each frame is passed with its timestamp from the demuxer to the muxer.
760 @item 1
761 Frames will be duplicated and dropped to achieve exactly the requested
762 constant framerate.
763 @item 2
764 Frames are passed through with their timestamp or dropped so as to
765 prevent 2 frames from having the same timestamp.
766 @item -1
767 Chooses between 1 and 2 depending on muxer capabilities. This is the
768 default method.
769 @end table
770
771 With -map you can select from which stream the timestamps should be
772 taken. You can leave either video or audio unchanged and sync the
773 remaining stream(s) to the unchanged one.
774
775 @item -async @var{samples_per_second}
776 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
777 the parameter is the maximum samples per second by which the audio is changed.
778 -async 1 is a special case where only the start of the audio stream is corrected
779 without any later correction.
780 @item -copyts
781 Copy timestamps from input to output.
782 @item -copytb
783 Copy input stream time base from input to output when stream copying.
784 @item -shortest
785 Finish encoding when the shortest input stream ends.
786 @item -dts_delta_threshold
787 Timestamp discontinuity delta threshold.
788 @item -muxdelay @var{seconds}
789 Set the maximum demux-decode delay.
790 @item -muxpreload @var{seconds}
791 Set the initial demux-decode delay.
792 @item -streamid @var{output-stream-index}:@var{new-value}
793 Assign a new stream-id value to an output stream. This option should be
794 specified prior to the output filename to which it applies.
795 For the situation where multiple output files exist, a streamid
796 may be reassigned to a different value.
797
798 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
799 an output mpegts file:
800 @example
801 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
802 @end example
803
804 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters}
805 Set bitstream filters for matching streams. @var{bistream_filters} is
806 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
807 to get the list of bitstream filters.
808 @example
809 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
810 @end example
811 @example
812 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
813 @end example
814 @end table
815 @c man end OPTIONS
816
817 @chapter Tips
818 @c man begin TIPS
819
820 @itemize
821 @item
822 For streaming at very low bitrate application, use a low frame rate
823 and a small GOP size. This is especially true for RealVideo where
824 the Linux player does not seem to be very fast, so it can miss
825 frames. An example is:
826
827 @example
828 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
829 @end example
830
831 @item
832 The parameter 'q' which is displayed while encoding is the current
833 quantizer. The value 1 indicates that a very good quality could
834 be achieved. The value 31 indicates the worst quality. If q=31 appears
835 too often, it means that the encoder cannot compress enough to meet
836 your bitrate. You must either increase the bitrate, decrease the
837 frame rate or decrease the frame size.
838
839 @item
840 If your computer is not fast enough, you can speed up the
841 compression at the expense of the compression ratio. You can use
842 '-me zero' to speed up motion estimation, and '-intra' to disable
843 motion estimation completely (you have only I-frames, which means it
844 is about as good as JPEG compression).
845
846 @item
847 To have very low audio bitrates, reduce the sampling frequency
848 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
849
850 @item
851 To have a constant quality (but a variable bitrate), use the option
852 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
853 quality).
854
855 @end itemize
856 @c man end TIPS
857
858 @chapter Examples
859 @c man begin EXAMPLES
860
861 @section Video and Audio grabbing
862
863 If you specify the input format and device then avconv can grab video
864 and audio directly.
865
866 @example
867 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
868 @end example
869
870 Note that you must activate the right video source and channel before
871 launching avconv with any TV viewer such as
872 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
873 have to set the audio recording levels correctly with a
874 standard mixer.
875
876 @section X11 grabbing
877
878 Grab the X11 display with avconv via
879
880 @example
881 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
882 @end example
883
884 0.0 is display.screen number of your X11 server, same as
885 the DISPLAY environment variable.
886
887 @example
888 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
889 @end example
890
891 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
892 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
893
894 @section Video and Audio file format conversion
895
896 Any supported file format and protocol can serve as input to avconv:
897
898 Examples:
899 @itemize
900 @item
901 You can use YUV files as input:
902
903 @example
904 avconv -i /tmp/test%d.Y /tmp/out.mpg
905 @end example
906
907 It will use the files:
908 @example
909 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
910 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
911 @end example
912
913 The Y files use twice the resolution of the U and V files. They are
914 raw files, without header. They can be generated by all decent video
915 decoders. You must specify the size of the image with the @option{-s} option
916 if avconv cannot guess it.
917
918 @item
919 You can input from a raw YUV420P file:
920
921 @example
922 avconv -i /tmp/test.yuv /tmp/out.avi
923 @end example
924
925 test.yuv is a file containing raw YUV planar data. Each frame is composed
926 of the Y plane followed by the U and V planes at half vertical and
927 horizontal resolution.
928
929 @item
930 You can output to a raw YUV420P file:
931
932 @example
933 avconv -i mydivx.avi hugefile.yuv
934 @end example
935
936 @item
937 You can set several input files and output files:
938
939 @example
940 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
941 @end example
942
943 Converts the audio file a.wav and the raw YUV video file a.yuv
944 to MPEG file a.mpg.
945
946 @item
947 You can also do audio and video conversions at the same time:
948
949 @example
950 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
951 @end example
952
953 Converts a.wav to MPEG audio at 22050 Hz sample rate.
954
955 @item
956 You can encode to several formats at the same time and define a
957 mapping from input stream to output streams:
958
959 @example
960 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
961 @end example
962
963 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
964 file:index' specifies which input stream is used for each output
965 stream, in the order of the definition of output streams.
966
967 @item
968 You can transcode decrypted VOBs:
969
970 @example
971 avconv -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi
972 @end example
973
974 This is a typical DVD ripping example; the input is a VOB file, the
975 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
976 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
977 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
978 input video. Furthermore, the audio stream is MP3-encoded so you need
979 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
980 The mapping is particularly useful for DVD transcoding
981 to get the desired audio language.
982
983 NOTE: To see the supported input formats, use @code{avconv -formats}.
984
985 @item
986 You can extract images from a video, or create a video from many images:
987
988 For extracting images from a video:
989 @example
990 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
991 @end example
992
993 This will extract one video frame per second from the video and will
994 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
995 etc. Images will be rescaled to fit the new WxH values.
996
997 If you want to extract just a limited number of frames, you can use the
998 above command in combination with the -vframes or -t option, or in
999 combination with -ss to start extracting from a certain point in time.
1000
1001 For creating a video from many images:
1002 @example
1003 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1004 @end example
1005
1006 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1007 composed of three digits padded with zeroes to express the sequence
1008 number. It is the same syntax supported by the C printf function, but
1009 only formats accepting a normal integer are suitable.
1010
1011 @item
1012 You can put many streams of the same type in the output:
1013
1014 @example
1015 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1016 @end example
1017
1018 The resulting output file @file{test12.avi} will contain first four streams from
1019 the input file in reverse order.
1020
1021 @end itemize
1022 @c man end EXAMPLES
1023
1024 @include eval.texi
1025 @include encoders.texi
1026 @include demuxers.texi
1027 @include muxers.texi
1028 @include indevs.texi
1029 @include outdevs.texi
1030 @include protocols.texi
1031 @include bitstream_filters.texi
1032 @include filters.texi
1033 @include metadata.texi
1034
1035 @ignore
1036
1037 @setfilename avconv
1038 @settitle avconv video converter
1039
1040 @c man begin SEEALSO
1041 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1042 @c man end
1043
1044 @c man begin AUTHORS
1045 The Libav developers
1046 @c man end
1047
1048 @end ignore
1049
1050 @bye