[libav.git] / doc / avconv.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle avconv Documentation
4 @titlepage
5 @center @titlefont{avconv Documentation}
6 @end titlepage
8 @top
10 @contents
12 @chapter Synopsis
14 The generic syntax is:
16 @example
17 @c man begin SYNOPSIS
18 avconv [global options] [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
19 @c man end
20 @end example
22 @chapter Description
23 @c man begin DESCRIPTION
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.
29 As a general rule, options are applied to the next specified
30 file. Therefore, order is important, and you can have the same
31 option on the command line multiple times. Each occurrence is
32 then applied to the next input or output file.
33 Exceptions from this rule are the global options (e.g. verbosity level),
34 which should be specified first.
36 @itemize
37 @item
38 To set the video bitrate of the output file to 64kbit/s:
39 @example
40 avconv -i input.avi -b 64k output.avi
41 @end example
43 @item
44 To force the frame rate of the output file to 24 fps:
45 @example
46 avconv -i input.avi -r 24 output.avi
47 @end example
49 @item
50 To force the frame rate of the input file (valid for raw formats only)
51 to 1 fps and the frame rate of the output file to 24 fps:
52 @example
53 avconv -r 1 -i input.m2v -r 24 output.avi
54 @end example
55 @end itemize
57 The format option may be needed for raw input files.
59 @c man end DESCRIPTION
61 @chapter Stream selection
62 @c man begin STREAM SELECTION
64 By default avconv tries to pick the "best" stream of each type present in input
65 files and add them to each output file. For video, this means the highest
66 resolution, for audio the highest channel count. For subtitle it's simply the
67 first subtitle stream.
69 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
70 full manual control, use the @code{-map} option, which disables the defaults just
71 described.
73 @c man end STREAM SELECTION
75 @chapter Options
76 @c man begin OPTIONS
78 @include avtools-common-opts.texi
80 @section Main options
82 @table @option
84 @item -f @var{fmt} (@emph{input/output})
85 Force input or output file format. The format is normally autodetected for input
86 files and guessed from file extension for output files, so this option is not
87 needed in most cases.
89 @item -i @var{filename} (@emph{input})
90 input file name
92 @item -y (@emph{global})
93 Overwrite output files without asking.
95 @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
96 @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
97 Select an encoder (when used before an output file) or a decoder (when used
98 before an input file) for one or more streams. @var{codec} is the name of a
99 decoder/encoder or a special value @code{copy} (output only) to indicate that
100 the stream is not to be reencoded.
102 For example
103 @example
104 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
105 @end example
106 encodes all video streams with libx264 and copies all audio streams.
108 For each stream, the last matching @code{c} option is applied, so
109 @example
110 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
111 @end example
112 will copy all the streams except the second video, which will be encoded with
113 libx264, and the 138th audio, which will be encoded with libvorbis.
115 @item -t @var{duration} (@emph{output})
116 Stop writing the output after its duration reaches @var{duration}.
117 @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
119 @item -fs @var{limit_size} (@emph{output})
120 Set the file size limit.
122 @item -ss @var{position} (@emph{input/output})
123 When used as an input option (before @code{-i}), seeks in this input file to
124 @var{position}. When used as an output option (before an output filename),
125 decodes but discards input until the timestamps reach @var{position}. This is
126 slower, but more accurate.
128 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
130 @item -itsoffset @var{offset} (@emph{input})
131 Set the input time offset in seconds.
132 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
133 The offset is added to the timestamps of the input files.
134 Specifying a positive offset means that the corresponding
135 streams are delayed by @var{offset} seconds.
137 @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
138 Set a metadata key/value pair.
140 An optional @var{metadata_specifier} may be given to set metadata
141 on streams or chapters. See @code{-map_metadata} documentation for
142 details.
144 This option overrides metadata set with @code{-map_metadata}. It is
145 also possible to delete metadata by using an empty value.
147 For example, for setting the title in the output file:
148 @example
149 avconv -i in.avi -metadata title="my title" out.flv
150 @end example
152 To set the language of the second stream:
153 @example
154 avconv -i INPUT -metadata:s:1 language=eng OUTPUT
155 @end example
157 @item -v @var{number} (@emph{global})
158 This option is deprecated and has no effect, use -loglevel
159 to set verbosity level.
161 @item -target @var{type} (@emph{output})
162 Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
163 @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
164 @code{film-} to use the corresponding standard. All the format options
165 (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
167 @example
168 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
169 @end example
171 Nevertheless you can specify additional options as long as you know
172 they do not conflict with the standard, as in:
174 @example
175 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
176 @end example
178 @item -dframes @var{number} (@emph{output})
179 Set the number of data frames to record. This is an alias for @code{-frames:d}.
181 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
182 Stop writing to the stream after @var{framecount} frames.
184 @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
185 @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
186 Use fixed quality scale (VBR). The meaning of @var{q} is
187 codec-dependent.
189 @item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
190 @var{filter_graph} is a description of the filter graph to apply to
191 the stream. Use @code{-filters} to show all the available filters
192 (including also sources and sinks).
194 @item -stats (@emph{global})
195 Print encoding progress/statistics. On by default.
197 @end table
199 @section Video Options
201 @table @option
202 @item -vframes @var{number} (@emph{output})
203 Set the number of video frames to record. This is an alias for @code{-frames:v}.
204 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
205 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
206 @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
207 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
208 The following abbreviations are recognized:
209 @table @samp
210 @item sqcif
211 128x96
212 @item qcif
213 176x144
214 @item cif
215 352x288
216 @item 4cif
217 704x576
218 @item 16cif
219 1408x1152
220 @item qqvga
221 160x120
222 @item qvga
223 320x240
224 @item vga
225 640x480
226 @item svga
227 800x600
228 @item xga
229 1024x768
230 @item uxga
231 1600x1200
232 @item qxga
233 2048x1536
234 @item sxga
235 1280x1024
236 @item qsxga
237 2560x2048
238 @item hsxga
239 5120x4096
240 @item wvga
241 852x480
242 @item wxga
243 1366x768
244 @item wsxga
245 1600x1024
246 @item wuxga
247 1920x1200
248 @item woxga
249 2560x1600
250 @item wqsxga
251 3200x2048
252 @item wquxga
253 3840x2400
254 @item whsxga
255 6400x4096
256 @item whuxga
257 7680x4800
258 @item cga
259 320x200
260 @item ega
261 640x350
262 @item hd480
263 852x480
264 @item hd720
265 1280x720
266 @item hd1080
267 1920x1080
268 @end table
270 @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
271 Set the video display aspect ratio specified by @var{aspect}.
273 @var{aspect} can be a floating point number string, or a string of the
274 form @var{num}:@var{den}, where @var{num} and @var{den} are the
275 numerator and denominator of the aspect ratio. For example "4:3",
276 "16:9", "1.3333", and "1.7777" are valid argument values.
278 @item -vn (@emph{output})
279 Disable video recording.
280 @item -bt @var{tolerance}
281 Set video bitrate tolerance (in bits, default 4000k).
282 Has a minimum value of: (target_bitrate/target_framerate).
283 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
284 willing to deviate from the target average bitrate value. This is
285 not related to min/max bitrate. Lowering tolerance too much has
286 an adverse effect on quality.
287 @item -maxrate @var{bitrate}
288 Set max video bitrate (in bit/s).
289 Requires -bufsize to be set.
290 @item -minrate @var{bitrate}
291 Set min video bitrate (in bit/s).
292 Most useful in setting up a CBR encode:
293 @example
294 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
295 @end example
296 It is of little use elsewise.
297 @item -bufsize @var{size}
298 Set video buffer verifier buffer size (in bits).
299 @item -vcodec @var{codec} (@emph{output})
300 Set the video codec. This is an alias for @code{-codec:v}.
301 @item -same_quant
302 Use same quantizer as source (implies VBR).
304 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
305 need it.
307 @item -pass @var{n}
308 Select the pass number (1 or 2). It is used to do two-pass
309 video encoding. The statistics of the video are recorded in the first
310 pass into a log file (see also the option -passlogfile),
311 and in the second pass that log file is used to generate the video
312 at the exact requested bitrate.
313 On pass 1, you may just deactivate audio and set output to null,
314 examples for Windows and Unix:
315 @example
316 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
317 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
318 @end example
320 @item -passlogfile @var{prefix} (@emph{global})
321 Set two-pass log file name prefix to @var{prefix}, the default file name
322 prefix is ``av2pass''. The complete file name will be
323 @file{PREFIX-N.log}, where N is a number specific to the output
324 stream.
326 @item -vf @var{filter_graph} (@emph{output})
327 @var{filter_graph} is a description of the filter graph to apply to
328 the input video.
329 Use the option "-filters" to show all the available filters (including
330 also sources and sinks). This is an alias for @code{-filter:v}.
332 @end table
334 @section Advanced Video Options
336 @table @option
337 @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
338 Set pixel format. Use @code{-pix_fmts} to show all the supported
339 pixel formats.
340 @item -sws_flags @var{flags} (@emph{input/output})
341 Set SwScaler flags.
342 @item -g @var{gop_size}
343 Set the group of pictures size.
344 @item -vdt @var{n}
345 Discard threshold.
346 @item -qmin @var{q}
347 minimum video quantizer scale (VBR)
348 @item -qmax @var{q}
349 maximum video quantizer scale (VBR)
350 @item -qdiff @var{q}
351 maximum difference between the quantizer scales (VBR)
352 @item -qblur @var{blur}
353 video quantizer scale blur (VBR) (range 0.0 - 1.0)
354 @item -qcomp @var{compression}
355 video quantizer scale compression (VBR) (default 0.5).
356 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
358 @item -lmin @var{lambda}
359 minimum video lagrange factor (VBR)
360 @item -lmax @var{lambda}
361 max video lagrange factor (VBR)
362 @item -mblmin @var{lambda}
363 minimum macroblock quantizer scale (VBR)
364 @item -mblmax @var{lambda}
365 maximum macroblock quantizer scale (VBR)
367 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
368 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
369 @example
370 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
371 @end example
373 @item -rc_init_cplx @var{complexity}
374 initial complexity for single pass encoding
375 @item -b_qfactor @var{factor}
376 qp factor between P- and B-frames
377 @item -i_qfactor @var{factor}
378 qp factor between P- and I-frames
379 @item -b_qoffset @var{offset}
380 qp offset between P- and B-frames
381 @item -i_qoffset @var{offset}
382 qp offset between P- and I-frames
383 @item -rc_eq @var{equation}
384 Set rate control equation (see section "Expression Evaluation")
385 (default = @code{tex^qComp}).
387 When computing the rate control equation expression, besides the
388 standard functions defined in the section "Expression Evaluation", the
389 following functions are available:
390 @table @var
391 @item bits2qp(bits)
392 @item qp2bits(qp)
393 @end table
395 and the following constants are available:
396 @table @var
397 @item iTex
398 @item pTex
399 @item tex
400 @item mv
401 @item fCode
402 @item iCount
403 @item mcVar
404 @item var
405 @item isI
406 @item isP
407 @item isB
408 @item avgQP
409 @item qComp
410 @item avgIITex
411 @item avgPITex
412 @item avgPPTex
413 @item avgBPTex
414 @item avgTex
415 @end table
417 @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
418 rate control override for specific intervals
419 @item -me_method @var{method}
420 Set motion estimation method to @var{method}.
421 Available methods are (from lowest to best quality):
422 @table @samp
423 @item zero
424 Try just the (0, 0) vector.
425 @item phods
426 @item log
427 @item x1
428 @item hex
429 @item umh
430 @item epzs
431 (default method)
432 @item full
433 exhaustive search (slow and marginally better than epzs)
434 @end table
436 @item -er @var{n}
437 Set error resilience to @var{n}.
438 @table @samp
439 @item 1
440 FF_ER_CAREFUL (default)
441 @item 2
443 @item 3
445 @item 4
447 @end table
449 @item -ec @var{bit_mask}
450 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
451 the following values:
452 @table @samp
453 @item 1
454 FF_EC_GUESS_MVS (default = enabled)
455 @item 2
456 FF_EC_DEBLOCK (default = enabled)
457 @end table
459 @item -bf @var{frames}
460 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
461 @item -mbd @var{mode}
462 macroblock decision
463 @table @samp
464 @item 0
465 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
466 @item 1
467 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
468 @item 2
469 FF_MB_DECISION_RD: rate distortion
470 @end table
472 @item -bug @var{param}
473 Work around encoder bugs that are not auto-detected.
474 @item -strict @var{strictness}
475 How strictly to follow the standards.
477 @item -deinterlace
478 Deinterlace pictures.
479 @item -vstats
480 Dump video coding statistics to @file{vstats_HHMMSS.log}.
481 @item -vstats_file @var{file}
482 Dump video coding statistics to @var{file}.
483 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
484 top=1/bottom=0/auto=-1 field first
485 @item -dc @var{precision}
486 Intra_dc_precision.
487 @item -vtag @var{fourcc/tag} (@emph{output})
488 Force video tag/fourcc. This is an alias for @code{-tag:v}.
489 @item -qphist (@emph{global})
490 Show QP histogram.
491 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
492 Force key frames at the specified timestamps, more precisely at the first
493 frames after each specified time.
494 This option can be useful to ensure that a seek point is present at a
495 chapter mark or any other designated place in the output file.
496 The timestamps must be specified in ascending order.
497 @end table
499 @section Audio Options
501 @table @option
502 @item -aframes @var{number} (@emph{output})
503 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
504 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
505 Set the audio sampling frequency. For output streams it is set by
506 default to the frequency of the corresponding input stream. For input
507 streams this option only makes sense for audio grabbing devices and raw
508 demuxers and is mapped to the corresponding demuxer options.
509 @item -aq @var{q} (@emph{output})
510 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
511 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
512 Set the number of audio channels. For output streams it is set by
513 default to the number of input audio channels. For input streams
514 this option only makes sense for audio grabbing devices and raw demuxers
515 and is mapped to the corresponding demuxer options.
516 @item -an (@emph{output})
517 Disable audio recording.
518 @item -acodec @var{codec} (@emph{input/output})
519 Set the audio codec. This is an alias for @code{-codec:a}.
520 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
521 Set the audio sample format. Use @code{-help sample_fmts} to get a list
522 of supported sample formats.
523 @end table
525 @section Advanced Audio options:
527 @table @option
528 @item -atag @var{fourcc/tag} (@emph{output})
529 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
530 @item -audio_service_type @var{type}
531 Set the type of service that the audio stream contains.
532 @table @option
533 @item ma
534 Main Audio Service (default)
535 @item ef
536 Effects
537 @item vi
538 Visually Impaired
539 @item hi
540 Hearing Impaired
541 @item di
542 Dialogue
543 @item co
544 Commentary
545 @item em
546 Emergency
547 @item vo
548 Voice Over
549 @item ka
550 Karaoke
551 @end table
552 @end table
554 @section Subtitle options:
556 @table @option
557 @item -scodec @var{codec} (@emph{input/output})
558 Set the subtitle codec. This is an alias for @code{-codec:s}.
559 @item -sn (@emph{output})
560 Disable subtitle recording.
561 @end table
563 @section Audio/Video grab options
565 @table @option
566 @item -isync (@emph{global})
567 Synchronize read on input.
568 @end table
570 @section Advanced options
572 @table @option
573 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output})
575 Designate one or more input streams as a source for the output file. Each input
576 stream is identified by the input file index @var{input_file_id} and
577 the input stream index @var{input_stream_id} within the input
578 file. Both indices start at 0. If specified,
579 @var{sync_file_id}:@var{stream_specifier} sets which input stream
580 is used as a presentation sync reference.
582 The first @code{-map} option on the command line specifies the
583 source for output stream 0, the second @code{-map} option specifies
584 the source for output stream 1, etc.
586 A @code{-} character before the stream identifier creates a "negative" mapping.
587 It disables matching streams from already created mappings.
589 For example, to map ALL streams from the first input file to output
590 @example
591 avconv -i INPUT -map 0 output
592 @end example
594 For example, if you have two audio streams in the first input file,
595 these streams are identified by "0:0" and "0:1". You can use
596 @code{-map} to select which streams to place in an output file. For
597 example:
598 @example
599 avconv -i INPUT -map 0:1 out.wav
600 @end example
601 will map the input stream in @file{INPUT} identified by "0:1" to
602 the (single) output stream in @file{out.wav}.
604 For example, to select the stream with index 2 from input file
605 @file{a.mov} (specified by the identifier "0:2"), and stream with
606 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
607 and copy them to the output file @file{out.mov}:
608 @example
609 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
610 @end example
612 To select all video and the third audio stream from an input file:
613 @example
614 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
615 @end example
617 To map all the streams except the second audio, use negative mappings
618 @example
619 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
620 @end example
622 Note that using this option disables the default mappings for this output file.
624 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] (@emph{output,per-metadata})
625 Set metadata information of the next output file from @var{infile}. Note that
626 those are file indices (zero-based), not filenames.
627 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
628 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
629 per-(p)rogram. All metadata specifiers other than global must be followed by the
630 stream/chapter/program index. If metadata specifier is omitted, it defaults to
631 global.
633 By default, global metadata is copied from the first input file,
634 per-stream and per-chapter metadata is copied along with streams/chapters. These
635 default mappings are disabled by creating any mapping of the relevant type. A negative
636 file index can be used to create a dummy mapping that just disables automatic copying.
638 For example to copy metadata from the first stream of the input file to global metadata
639 of the output file:
640 @example
641 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
642 @end example
643 @item -map_chapters @var{input_file_index} (@emph{output})
644 Copy chapters from input file with index @var{input_file_index} to the next
645 output file. If no chapter mapping is specified, then chapters are copied from
646 the first input file with at least one chapter. Use a negative file index to
647 disable any chapter copying.
648 @item -debug
649 Print specific debug info.
650 @item -benchmark (@emph{global})
651 Show benchmarking information at the end of an encode.
652 Shows CPU time used and maximum memory consumption.
653 Maximum memory consumption is not supported on all systems,
654 it will usually display as 0 if not supported.
655 @item -timelimit @var{duration} (@emph{global})
656 Exit after avconv has been running for @var{duration} seconds.
657 @item -dump (@emph{global})
658 Dump each input packet to stderr.
659 @item -hex (@emph{global})
660 When dumping packets, also dump the payload.
661 @item -ps @var{size}
662 Set RTP payload size in bytes.
663 @item -re (@emph{input})
664 Read input at native frame rate. Mainly used to simulate a grab device.
665 @item -threads @var{count}
666 Thread count.
667 @item -vsync @var{parameter}
668 Video sync method.
670 @table @option
671 @item 0
672 Each frame is passed with its timestamp from the demuxer to the muxer.
673 @item 1
674 Frames will be duplicated and dropped to achieve exactly the requested
675 constant framerate.
676 @item 2
677 Frames are passed through with their timestamp or dropped so as to
678 prevent 2 frames from having the same timestamp.
679 @item -1
680 Chooses between 1 and 2 depending on muxer capabilities. This is the
681 default method.
682 @end table
684 With -map you can select from which stream the timestamps should be
685 taken. You can leave either video or audio unchanged and sync the
686 remaining stream(s) to the unchanged one.
688 @item -async @var{samples_per_second}
689 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
690 the parameter is the maximum samples per second by which the audio is changed.
691 -async 1 is a special case where only the start of the audio stream is corrected
692 without any later correction.
693 @item -copyts
694 Copy timestamps from input to output.
695 @item -copytb
696 Copy input stream time base from input to output when stream copying.
697 @item -shortest
698 Finish encoding when the shortest input stream ends.
699 @item -dts_delta_threshold
700 Timestamp discontinuity delta threshold.
701 @item -muxdelay @var{seconds} (@emph{input})
702 Set the maximum demux-decode delay.
703 @item -muxpreload @var{seconds} (@emph{input})
704 Set the initial demux-decode delay.
705 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
706 Assign a new stream-id value to an output stream. This option should be
707 specified prior to the output filename to which it applies.
708 For the situation where multiple output files exist, a streamid
709 may be reassigned to a different value.
711 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
712 an output mpegts file:
713 @example
714 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
715 @end example
717 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
718 Set bitstream filters for matching streams. @var{bistream_filters} is
719 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
720 to get the list of bitstream filters.
721 @example
722 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
723 @end example
724 @example
725 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
726 @end example
728 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{output,per-stream})
729 Force a tag/fourcc for matching streams.
730 @end table
731 @c man end OPTIONS
733 @chapter Tips
734 @c man begin TIPS
736 @itemize
737 @item
738 For streaming at very low bitrate application, use a low frame rate
739 and a small GOP size. This is especially true for RealVideo where
740 the Linux player does not seem to be very fast, so it can miss
741 frames. An example is:
743 @example
744 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
745 @end example
747 @item
748 The parameter 'q' which is displayed while encoding is the current
749 quantizer. The value 1 indicates that a very good quality could
750 be achieved. The value 31 indicates the worst quality. If q=31 appears
751 too often, it means that the encoder cannot compress enough to meet
752 your bitrate. You must either increase the bitrate, decrease the
753 frame rate or decrease the frame size.
755 @item
756 If your computer is not fast enough, you can speed up the
757 compression at the expense of the compression ratio. You can use
758 '-me zero' to speed up motion estimation, and '-intra' to disable
759 motion estimation completely (you have only I-frames, which means it
760 is about as good as JPEG compression).
762 @item
763 To have very low audio bitrates, reduce the sampling frequency
764 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
766 @item
767 To have a constant quality (but a variable bitrate), use the option
768 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
769 quality).
771 @end itemize
772 @c man end TIPS
774 @chapter Examples
775 @c man begin EXAMPLES
777 @section Video and Audio grabbing
779 If you specify the input format and device then avconv can grab video
780 and audio directly.
782 @example
783 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
784 @end example
786 Note that you must activate the right video source and channel before
787 launching avconv with any TV viewer such as
788 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
789 have to set the audio recording levels correctly with a
790 standard mixer.
792 @section X11 grabbing
794 Grab the X11 display with avconv via
796 @example
797 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
798 @end example
800 0.0 is display.screen number of your X11 server, same as
801 the DISPLAY environment variable.
803 @example
804 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
805 @end example
807 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
808 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
810 @section Video and Audio file format conversion
812 Any supported file format and protocol can serve as input to avconv:
814 Examples:
815 @itemize
816 @item
817 You can use YUV files as input:
819 @example
820 avconv -i /tmp/test%d.Y /tmp/out.mpg
821 @end example
823 It will use the files:
824 @example
825 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
826 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
827 @end example
829 The Y files use twice the resolution of the U and V files. They are
830 raw files, without header. They can be generated by all decent video
831 decoders. You must specify the size of the image with the @option{-s} option
832 if avconv cannot guess it.
834 @item
835 You can input from a raw YUV420P file:
837 @example
838 avconv -i /tmp/test.yuv /tmp/out.avi
839 @end example
841 test.yuv is a file containing raw YUV planar data. Each frame is composed
842 of the Y plane followed by the U and V planes at half vertical and
843 horizontal resolution.
845 @item
846 You can output to a raw YUV420P file:
848 @example
849 avconv -i mydivx.avi hugefile.yuv
850 @end example
852 @item
853 You can set several input files and output files:
855 @example
856 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
857 @end example
859 Converts the audio file a.wav and the raw YUV video file a.yuv
860 to MPEG file a.mpg.
862 @item
863 You can also do audio and video conversions at the same time:
865 @example
866 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
867 @end example
869 Converts a.wav to MPEG audio at 22050 Hz sample rate.
871 @item
872 You can encode to several formats at the same time and define a
873 mapping from input stream to output streams:
875 @example
876 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
877 @end example
879 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
880 file:index' specifies which input stream is used for each output
881 stream, in the order of the definition of output streams.
883 @item
884 You can transcode decrypted VOBs:
886 @example
887 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
888 @end example
890 This is a typical DVD ripping example; the input is a VOB file, the
891 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
892 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
893 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
894 input video. Furthermore, the audio stream is MP3-encoded so you need
895 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
896 The mapping is particularly useful for DVD transcoding
897 to get the desired audio language.
899 NOTE: To see the supported input formats, use @code{avconv -formats}.
901 @item
902 You can extract images from a video, or create a video from many images:
904 For extracting images from a video:
905 @example
906 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
907 @end example
909 This will extract one video frame per second from the video and will
910 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
911 etc. Images will be rescaled to fit the new WxH values.
913 If you want to extract just a limited number of frames, you can use the
914 above command in combination with the -vframes or -t option, or in
915 combination with -ss to start extracting from a certain point in time.
917 For creating a video from many images:
918 @example
919 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
920 @end example
922 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
923 composed of three digits padded with zeroes to express the sequence
924 number. It is the same syntax supported by the C printf function, but
925 only formats accepting a normal integer are suitable.
927 @item
928 You can put many streams of the same type in the output:
930 @example
931 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
932 @end example
934 The resulting output file @file{test12.avi} will contain first four streams from
935 the input file in reverse order.
937 @end itemize
938 @c man end EXAMPLES
940 @include eval.texi
941 @include encoders.texi
942 @include demuxers.texi
943 @include muxers.texi
944 @include indevs.texi
945 @include outdevs.texi
946 @include protocols.texi
947 @include bitstream_filters.texi
948 @include filters.texi
949 @include metadata.texi
951 @ignore
953 @setfilename avconv
954 @settitle avconv video converter
956 @c man begin SEEALSO
957 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
958 @c man end
960 @c man begin AUTHORS
961 The Libav developers
962 @c man end
964 @end ignore
966 @bye