959b781349ce67108521b02eb14f24cdd3389a14
[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 @var{key}=@var{value}
164 Set a metadata key/value pair.
165
166 For example, for setting the title in the output file:
167 @example
168 avconv -i in.avi -metadata title="my title" out.flv
169 @end example
170
171 @item -v @var{number}
172 Set the logging verbosity level.
173
174 @item -target @var{type}
175 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
176 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
177 buffer sizes) are then set automatically. You can just type:
178
179 @example
180 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
181 @end example
182
183 Nevertheless you can specify additional options as long as you know
184 they do not conflict with the standard, as in:
185
186 @example
187 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
188 @end example
189
190 @item -dframes @var{number}
191 Set the number of data frames to record.
192
193 @item -slang @var{code}
194 Set the ISO 639 language code (3 letters) of the current subtitle stream.
195
196 @end table
197
198 @section Video Options
199
200 @table @option
201 @item -vframes @var{number}
202 Set the number of video frames to record.
203 @item -r @var{fps}
204 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
205 @item -s @var{size}
206 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
207 The following abbreviations are recognized:
208 @table @samp
209 @item sqcif
210 128x96
211 @item qcif
212 176x144
213 @item cif
214 352x288
215 @item 4cif
216 704x576
217 @item 16cif
218 1408x1152
219 @item qqvga
220 160x120
221 @item qvga
222 320x240
223 @item vga
224 640x480
225 @item svga
226 800x600
227 @item xga
228 1024x768
229 @item uxga
230 1600x1200
231 @item qxga
232 2048x1536
233 @item sxga
234 1280x1024
235 @item qsxga
236 2560x2048
237 @item hsxga
238 5120x4096
239 @item wvga
240 852x480
241 @item wxga
242 1366x768
243 @item wsxga
244 1600x1024
245 @item wuxga
246 1920x1200
247 @item woxga
248 2560x1600
249 @item wqsxga
250 3200x2048
251 @item wquxga
252 3840x2400
253 @item whsxga
254 6400x4096
255 @item whuxga
256 7680x4800
257 @item cga
258 320x200
259 @item ega
260 640x350
261 @item hd480
262 852x480
263 @item hd720
264 1280x720
265 @item hd1080
266 1920x1080
267 @end table
268
269 @item -aspect @var{aspect}
270 Set the video display aspect ratio specified by @var{aspect}.
271
272 @var{aspect} can be a floating point number string, or a string of the
273 form @var{num}:@var{den}, where @var{num} and @var{den} are the
274 numerator and denominator of the aspect ratio. For example "4:3",
275 "16:9", "1.3333", and "1.7777" are valid argument values.
276
277 @item -vn
278 Disable video recording.
279 @item -bt @var{tolerance}
280 Set video bitrate tolerance (in bits, default 4000k).
281 Has a minimum value of: (target_bitrate/target_framerate).
282 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
283 willing to deviate from the target average bitrate value. This is
284 not related to min/max bitrate. Lowering tolerance too much has
285 an adverse effect on quality.
286 @item -maxrate @var{bitrate}
287 Set max video bitrate (in bit/s).
288 Requires -bufsize to be set.
289 @item -minrate @var{bitrate}
290 Set min video bitrate (in bit/s).
291 Most useful in setting up a CBR encode:
292 @example
293 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
294 @end example
295 It is of little use elsewise.
296 @item -bufsize @var{size}
297 Set video buffer verifier buffer size (in bits).
298 @item -vcodec @var{codec}
299 Set the video codec. This is an alias for @code{-codec:v}.
300 @item -same_quant
301 Use same quantizer as source (implies VBR).
302
303 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
304 need it.
305
306 @item -pass @var{n}
307 Select the pass number (1 or 2). It is used to do two-pass
308 video encoding. The statistics of the video are recorded in the first
309 pass into a log file (see also the option -passlogfile),
310 and in the second pass that log file is used to generate the video
311 at the exact requested bitrate.
312 On pass 1, you may just deactivate audio and set output to null,
313 examples for Windows and Unix:
314 @example
315 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
316 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
317 @end example
318
319 @item -passlogfile @var{prefix}
320 Set two-pass log file name prefix to @var{prefix}, the default file name
321 prefix is ``av2pass''. The complete file name will be
322 @file{PREFIX-N.log}, where N is a number specific to the output
323 stream.
324
325 @item -vlang @var{code}
326 Set the ISO 639 language code (3 letters) of the current video stream.
327
328 @item -vf @var{filter_graph}
329 @var{filter_graph} is a description of the filter graph to apply to
330 the input video.
331 Use the option "-filters" to show all the available filters (including
332 also sources and sinks).
333
334 @end table
335
336 @section Advanced Video Options
337
338 @table @option
339 @item -pix_fmt @var{format}
340 Set pixel format. Use 'list' as parameter to show all the supported
341 pixel formats.
342 @item -sws_flags @var{flags}
343 Set SwScaler flags.
344 @item -g @var{gop_size}
345 Set the group of pictures size.
346 @item -vdt @var{n}
347 Discard threshold.
348 @item -qscale @var{q}
349 Use fixed video quantizer scale (VBR).
350 @item -qmin @var{q}
351 minimum video quantizer scale (VBR)
352 @item -qmax @var{q}
353 maximum video quantizer scale (VBR)
354 @item -qdiff @var{q}
355 maximum difference between the quantizer scales (VBR)
356 @item -qblur @var{blur}
357 video quantizer scale blur (VBR) (range 0.0 - 1.0)
358 @item -qcomp @var{compression}
359 video quantizer scale compression (VBR) (default 0.5).
360 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
361
362 @item -lmin @var{lambda}
363 minimum video lagrange factor (VBR)
364 @item -lmax @var{lambda}
365 max video lagrange factor (VBR)
366 @item -mblmin @var{lambda}
367 minimum macroblock quantizer scale (VBR)
368 @item -mblmax @var{lambda}
369 maximum macroblock quantizer scale (VBR)
370
371 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
372 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
373 @example
374 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
375 @end example
376
377 @item -rc_init_cplx @var{complexity}
378 initial complexity for single pass encoding
379 @item -b_qfactor @var{factor}
380 qp factor between P- and B-frames
381 @item -i_qfactor @var{factor}
382 qp factor between P- and I-frames
383 @item -b_qoffset @var{offset}
384 qp offset between P- and B-frames
385 @item -i_qoffset @var{offset}
386 qp offset between P- and I-frames
387 @item -rc_eq @var{equation}
388 Set rate control equation (see section "Expression Evaluation")
389 (default = @code{tex^qComp}).
390
391 When computing the rate control equation expression, besides the
392 standard functions defined in the section "Expression Evaluation", the
393 following functions are available:
394 @table @var
395 @item bits2qp(bits)
396 @item qp2bits(qp)
397 @end table
398
399 and the following constants are available:
400 @table @var
401 @item iTex
402 @item pTex
403 @item tex
404 @item mv
405 @item fCode
406 @item iCount
407 @item mcVar
408 @item var
409 @item isI
410 @item isP
411 @item isB
412 @item avgQP
413 @item qComp
414 @item avgIITex
415 @item avgPITex
416 @item avgPPTex
417 @item avgBPTex
418 @item avgTex
419 @end table
420
421 @item -rc_override @var{override}
422 rate control override for specific intervals
423 @item -me_method @var{method}
424 Set motion estimation method to @var{method}.
425 Available methods are (from lowest to best quality):
426 @table @samp
427 @item zero
428 Try just the (0, 0) vector.
429 @item phods
430 @item log
431 @item x1
432 @item hex
433 @item umh
434 @item epzs
435 (default method)
436 @item full
437 exhaustive search (slow and marginally better than epzs)
438 @end table
439
440 @item -dct_algo @var{algo}
441 Set DCT algorithm to @var{algo}. Available values are:
442 @table @samp
443 @item 0
444 FF_DCT_AUTO (default)
445 @item 1
446 FF_DCT_FASTINT
447 @item 2
448 FF_DCT_INT
449 @item 3
450 FF_DCT_MMX
451 @item 4
452 FF_DCT_MLIB
453 @item 5
454 FF_DCT_ALTIVEC
455 @end table
456
457 @item -idct_algo @var{algo}
458 Set IDCT algorithm to @var{algo}. Available values are:
459 @table @samp
460 @item 0
461 FF_IDCT_AUTO (default)
462 @item 1
463 FF_IDCT_INT
464 @item 2
465 FF_IDCT_SIMPLE
466 @item 3
467 FF_IDCT_SIMPLEMMX
468 @item 4
469 FF_IDCT_LIBMPEG2MMX
470 @item 5
471 FF_IDCT_PS2
472 @item 6
473 FF_IDCT_MLIB
474 @item 7
475 FF_IDCT_ARM
476 @item 8
477 FF_IDCT_ALTIVEC
478 @item 9
479 FF_IDCT_SH4
480 @item 10
481 FF_IDCT_SIMPLEARM
482 @end table
483
484 @item -er @var{n}
485 Set error resilience to @var{n}.
486 @table @samp
487 @item 1
488 FF_ER_CAREFUL (default)
489 @item 2
490 FF_ER_COMPLIANT
491 @item 3
492 FF_ER_AGGRESSIVE
493 @item 4
494 FF_ER_VERY_AGGRESSIVE
495 @end table
496
497 @item -ec @var{bit_mask}
498 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
499 the following values:
500 @table @samp
501 @item 1
502 FF_EC_GUESS_MVS (default = enabled)
503 @item 2
504 FF_EC_DEBLOCK (default = enabled)
505 @end table
506
507 @item -bf @var{frames}
508 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
509 @item -mbd @var{mode}
510 macroblock decision
511 @table @samp
512 @item 0
513 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
514 @item 1
515 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
516 @item 2
517 FF_MB_DECISION_RD: rate distortion
518 @end table
519
520 @item -4mv
521 Use four motion vector by macroblock (MPEG-4 only).
522 @item -part
523 Use data partitioning (MPEG-4 only).
524 @item -bug @var{param}
525 Work around encoder bugs that are not auto-detected.
526 @item -strict @var{strictness}
527 How strictly to follow the standards.
528 @item -aic
529 Enable Advanced intra coding (h263+).
530 @item -umv
531 Enable Unlimited Motion Vector (h263+)
532
533 @item -deinterlace
534 Deinterlace pictures.
535 @item -ilme
536 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
537 Use this option if your input file is interlaced and you want
538 to keep the interlaced format for minimum losses.
539 The alternative is to deinterlace the input stream with
540 @option{-deinterlace}, but deinterlacing introduces losses.
541 @item -psnr
542 Calculate PSNR of compressed frames.
543 @item -vstats
544 Dump video coding statistics to @file{vstats_HHMMSS.log}.
545 @item -vstats_file @var{file}
546 Dump video coding statistics to @var{file}.
547 @item -top @var{n}
548 top=1/bottom=0/auto=-1 field first
549 @item -dc @var{precision}
550 Intra_dc_precision.
551 @item -vtag @var{fourcc/tag}
552 Force video tag/fourcc.
553 @item -qphist
554 Show QP histogram.
555 @item -vbsf @var{bitstream_filter}
556 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
557 @example
558 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
559 @end example
560 @item -force_key_frames @var{time}[,@var{time}...]
561 Force key frames at the specified timestamps, more precisely at the first
562 frames after each specified time.
563 This option can be useful to ensure that a seek point is present at a
564 chapter mark or any other designated place in the output file.
565 The timestamps must be specified in ascending order.
566 @end table
567
568 @section Audio Options
569
570 @table @option
571 @item -aframes @var{number}
572 Set the number of audio frames to record.
573 @item -ar @var{freq}
574 Set the audio sampling frequency. For output streams it is set by
575 default to the frequency of the corresponding input stream. For input
576 streams this option only makes sense for audio grabbing devices and raw
577 demuxers and is mapped to the corresponding demuxer options.
578 @item -aq @var{q}
579 Set the audio quality (codec-specific, VBR).
580 @item -ac @var{channels}
581 Set the number of audio channels. For output streams it is set by
582 default to the number of input audio channels. For input streams
583 this option only makes sense for audio grabbing devices and raw demuxers
584 and is mapped to the corresponding demuxer options.
585 @item -an
586 Disable audio recording.
587 @item -acodec @var{codec}
588 Set the audio codec. This is an alias for @code{-codec:a}.
589 @item -alang @var{code}
590 Set the ISO 639 language code (3 letters) of the current audio stream.
591 @end table
592
593 @section Advanced Audio options:
594
595 @table @option
596 @item -atag @var{fourcc/tag}
597 Force audio tag/fourcc.
598 @item -audio_service_type @var{type}
599 Set the type of service that the audio stream contains.
600 @table @option
601 @item ma
602 Main Audio Service (default)
603 @item ef
604 Effects
605 @item vi
606 Visually Impaired
607 @item hi
608 Hearing Impaired
609 @item di
610 Dialogue
611 @item co
612 Commentary
613 @item em
614 Emergency
615 @item vo
616 Voice Over
617 @item ka
618 Karaoke
619 @end table
620 @item -absf @var{bitstream_filter}
621 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
622 @end table
623
624 @section Subtitle options:
625
626 @table @option
627 @item -scodec @var{codec}
628 Set the subtitle codec. This is an alias for @code{-codec:s}.
629 @item -slang @var{code}
630 Set the ISO 639 language code (3 letters) of the current subtitle stream.
631 @item -sn
632 Disable subtitle recording.
633 @item -sbsf @var{bitstream_filter}
634 Bitstream filters available are "mov2textsub", "text2movsub".
635 @example
636 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
637 @end example
638 @end table
639
640 @section Audio/Video grab options
641
642 @table @option
643 @item -isync
644 Synchronize read on input.
645 @end table
646
647 @section Advanced options
648
649 @table @option
650 @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}]]
651
652 Designate one or more input streams as a source for the output file. Each input
653 stream is identified by the input file index @var{input_file_id} and
654 the input stream index @var{input_stream_id} within the input
655 file. Both indices start at 0. If specified,
656 @var{sync_file_id}:@var{sync_stream_id} sets which input stream
657 is used as a presentation sync reference.
658
659 If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
660 subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
661 of this type. Same for @var{sync_stream_type}.
662
663 @var{input_stream_id} may be omitted, in which case all streams of the given
664 type are mapped (or all streams in the file, if no type is specified).
665
666 The first @code{-map} option on the command line specifies the
667 source for output stream 0, the second @code{-map} option specifies
668 the source for output stream 1, etc.
669
670 A @code{-} character before the stream identifier creates a "negative" mapping.
671 It disables matching streams from already created mappings.
672
673 For example, to map ALL streams from the first input file to output
674 @example
675 avconv -i INPUT -map 0 output
676 @end example
677
678 For example, if you have two audio streams in the first input file,
679 these streams are identified by "0:0" and "0:1". You can use
680 @code{-map} to select which streams to place in an output file. For
681 example:
682 @example
683 avconv -i INPUT -map 0:1 out.wav
684 @end example
685 will map the input stream in @file{INPUT} identified by "0:1" to
686 the (single) output stream in @file{out.wav}.
687
688 For example, to select the stream with index 2 from input file
689 @file{a.mov} (specified by the identifier "0:2"), and stream with
690 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
691 and copy them to the output file @file{out.mov}:
692 @example
693 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
694 @end example
695
696 To select all video and the third audio stream from an input file:
697 @example
698 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
699 @end example
700
701 To map all the streams except the second audio, use negative mappings
702 @example
703 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
704 @end example
705
706 Note that using this option disables the default mappings for this output file.
707
708 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
709 Set metadata information of the next output file from @var{infile}. Note that
710 those are file indices (zero-based), not filenames.
711 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
712 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
713 per-(p)rogram. All metadata specifiers other than global must be followed by the
714 stream/chapter/program index. If metadata specifier is omitted, it defaults to
715 global.
716
717 By default, global metadata is copied from the first input file,
718 per-stream and per-chapter metadata is copied along with streams/chapters. These
719 default mappings are disabled by creating any mapping of the relevant type. A negative
720 file index can be used to create a dummy mapping that just disables automatic copying.
721
722 For example to copy metadata from the first stream of the input file to global metadata
723 of the output file:
724 @example
725 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
726 @end example
727 @item -map_chapters @var{input_file_index}
728 Copy chapters from input file with index @var{input_file_index} to the next
729 output file. If no chapter mapping is specified, then chapters are copied from
730 the first input file with at least one chapter. Use a negative file index to
731 disable any chapter copying.
732 @item -debug
733 Print specific debug info.
734 @item -benchmark
735 Show benchmarking information at the end of an encode.
736 Shows CPU time used and maximum memory consumption.
737 Maximum memory consumption is not supported on all systems,
738 it will usually display as 0 if not supported.
739 @item -dump
740 Dump each input packet.
741 @item -hex
742 When dumping packets, also dump the payload.
743 @item -bitexact
744 Only use bit exact algorithms (for codec testing).
745 @item -ps @var{size}
746 Set RTP payload size in bytes.
747 @item -re
748 Read input at native frame rate. Mainly used to simulate a grab device.
749 @item -threads @var{count}
750 Thread count.
751 @item -vsync @var{parameter}
752 Video sync method.
753
754 @table @option
755 @item 0
756 Each frame is passed with its timestamp from the demuxer to the muxer.
757 @item 1
758 Frames will be duplicated and dropped to achieve exactly the requested
759 constant framerate.
760 @item 2
761 Frames are passed through with their timestamp or dropped so as to
762 prevent 2 frames from having the same timestamp.
763 @item -1
764 Chooses between 1 and 2 depending on muxer capabilities. This is the
765 default method.
766 @end table
767
768 With -map you can select from which stream the timestamps should be
769 taken. You can leave either video or audio unchanged and sync the
770 remaining stream(s) to the unchanged one.
771
772 @item -async @var{samples_per_second}
773 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
774 the parameter is the maximum samples per second by which the audio is changed.
775 -async 1 is a special case where only the start of the audio stream is corrected
776 without any later correction.
777 @item -copyts
778 Copy timestamps from input to output.
779 @item -copytb
780 Copy input stream time base from input to output when stream copying.
781 @item -shortest
782 Finish encoding when the shortest input stream ends.
783 @item -dts_delta_threshold
784 Timestamp discontinuity delta threshold.
785 @item -muxdelay @var{seconds}
786 Set the maximum demux-decode delay.
787 @item -muxpreload @var{seconds}
788 Set the initial demux-decode delay.
789 @item -streamid @var{output-stream-index}:@var{new-value}
790 Assign a new stream-id value to an output stream. This option should be
791 specified prior to the output filename to which it applies.
792 For the situation where multiple output files exist, a streamid
793 may be reassigned to a different value.
794
795 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
796 an output mpegts file:
797 @example
798 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
799 @end example
800 @end table
801 @c man end OPTIONS
802
803 @chapter Tips
804 @c man begin TIPS
805
806 @itemize
807 @item
808 For streaming at very low bitrate application, use a low frame rate
809 and a small GOP size. This is especially true for RealVideo where
810 the Linux player does not seem to be very fast, so it can miss
811 frames. An example is:
812
813 @example
814 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
815 @end example
816
817 @item
818 The parameter 'q' which is displayed while encoding is the current
819 quantizer. The value 1 indicates that a very good quality could
820 be achieved. The value 31 indicates the worst quality. If q=31 appears
821 too often, it means that the encoder cannot compress enough to meet
822 your bitrate. You must either increase the bitrate, decrease the
823 frame rate or decrease the frame size.
824
825 @item
826 If your computer is not fast enough, you can speed up the
827 compression at the expense of the compression ratio. You can use
828 '-me zero' to speed up motion estimation, and '-intra' to disable
829 motion estimation completely (you have only I-frames, which means it
830 is about as good as JPEG compression).
831
832 @item
833 To have very low audio bitrates, reduce the sampling frequency
834 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
835
836 @item
837 To have a constant quality (but a variable bitrate), use the option
838 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
839 quality).
840
841 @end itemize
842 @c man end TIPS
843
844 @chapter Examples
845 @c man begin EXAMPLES
846
847 @section Video and Audio grabbing
848
849 If you specify the input format and device then avconv can grab video
850 and audio directly.
851
852 @example
853 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
854 @end example
855
856 Note that you must activate the right video source and channel before
857 launching avconv with any TV viewer such as
858 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
859 have to set the audio recording levels correctly with a
860 standard mixer.
861
862 @section X11 grabbing
863
864 Grab the X11 display with avconv via
865
866 @example
867 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
868 @end example
869
870 0.0 is display.screen number of your X11 server, same as
871 the DISPLAY environment variable.
872
873 @example
874 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
875 @end example
876
877 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
878 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
879
880 @section Video and Audio file format conversion
881
882 Any supported file format and protocol can serve as input to avconv:
883
884 Examples:
885 @itemize
886 @item
887 You can use YUV files as input:
888
889 @example
890 avconv -i /tmp/test%d.Y /tmp/out.mpg
891 @end example
892
893 It will use the files:
894 @example
895 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
896 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
897 @end example
898
899 The Y files use twice the resolution of the U and V files. They are
900 raw files, without header. They can be generated by all decent video
901 decoders. You must specify the size of the image with the @option{-s} option
902 if avconv cannot guess it.
903
904 @item
905 You can input from a raw YUV420P file:
906
907 @example
908 avconv -i /tmp/test.yuv /tmp/out.avi
909 @end example
910
911 test.yuv is a file containing raw YUV planar data. Each frame is composed
912 of the Y plane followed by the U and V planes at half vertical and
913 horizontal resolution.
914
915 @item
916 You can output to a raw YUV420P file:
917
918 @example
919 avconv -i mydivx.avi hugefile.yuv
920 @end example
921
922 @item
923 You can set several input files and output files:
924
925 @example
926 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
927 @end example
928
929 Converts the audio file a.wav and the raw YUV video file a.yuv
930 to MPEG file a.mpg.
931
932 @item
933 You can also do audio and video conversions at the same time:
934
935 @example
936 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
937 @end example
938
939 Converts a.wav to MPEG audio at 22050 Hz sample rate.
940
941 @item
942 You can encode to several formats at the same time and define a
943 mapping from input stream to output streams:
944
945 @example
946 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
947 @end example
948
949 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
950 file:index' specifies which input stream is used for each output
951 stream, in the order of the definition of output streams.
952
953 @item
954 You can transcode decrypted VOBs:
955
956 @example
957 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
958 @end example
959
960 This is a typical DVD ripping example; the input is a VOB file, the
961 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
962 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
963 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
964 input video. Furthermore, the audio stream is MP3-encoded so you need
965 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
966 The mapping is particularly useful for DVD transcoding
967 to get the desired audio language.
968
969 NOTE: To see the supported input formats, use @code{avconv -formats}.
970
971 @item
972 You can extract images from a video, or create a video from many images:
973
974 For extracting images from a video:
975 @example
976 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
977 @end example
978
979 This will extract one video frame per second from the video and will
980 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
981 etc. Images will be rescaled to fit the new WxH values.
982
983 If you want to extract just a limited number of frames, you can use the
984 above command in combination with the -vframes or -t option, or in
985 combination with -ss to start extracting from a certain point in time.
986
987 For creating a video from many images:
988 @example
989 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
990 @end example
991
992 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
993 composed of three digits padded with zeroes to express the sequence
994 number. It is the same syntax supported by the C printf function, but
995 only formats accepting a normal integer are suitable.
996
997 @item
998 You can put many streams of the same type in the output:
999
1000 @example
1001 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1002 @end example
1003
1004 The resulting output file @file{test12.avi} will contain first four streams from
1005 the input file in reverse order.
1006
1007 @end itemize
1008 @c man end EXAMPLES
1009
1010 @include eval.texi
1011 @include encoders.texi
1012 @include demuxers.texi
1013 @include muxers.texi
1014 @include indevs.texi
1015 @include outdevs.texi
1016 @include protocols.texi
1017 @include bitstream_filters.texi
1018 @include filters.texi
1019 @include metadata.texi
1020
1021 @ignore
1022
1023 @setfilename avconv
1024 @settitle avconv video converter
1025
1026 @c man begin SEEALSO
1027 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1028 @c man end
1029
1030 @c man begin AUTHORS
1031 The Libav developers
1032 @c man end
1033
1034 @end ignore
1035
1036 @bye