1 \input texinfo @c -*- texinfo -*-
3 @settitle avconv Documentation
5 @center @titlefont{avconv Documentation}
14 The generic syntax is:
18 avconv [global options] [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
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 avconv reads from an arbitrary number of input "files" (which can be regular
30 files, pipes, network streams, grabbing devices, etc.), specified by the
31 @code{-i} option, and writes to an arbitrary number of output "files", which are
32 specified by a plain output filename. Anything found on the commandline which
33 cannot be interpreted as an option is considered to be an output filename.
35 Each input or output file can in principle contain any number of streams of
36 different types (video/audio/subtitle/attachment/data). Allowed number and/or
37 types of streams can be limited by the container format. Selecting, which
38 streams from which inputs go into output, is done either automatically or with
39 the @code{-map} option (see the Stream selection chapter).
41 To refer to input files in options, you must use their indices (0-based). E.g.
42 the first input file is @code{0}, the second is @code{1} etc. Similarly, streams
43 within a file are referred to by their indices. E.g. @code{2:3} refers to the
44 fourth stream in the third input file. See also the Stream specifiers chapter.
46 As a general rule, options are applied to the next specified
47 file. Therefore, order is important, and you can have the same
48 option on the command line multiple times. Each occurrence is
49 then applied to the next input or output file.
50 Exceptions from this rule are the global options (e.g. verbosity level),
51 which should be specified first.
53 Do not mix input and output files -- first specify all input files, then all
54 output files. Also do not mix options which belong to different files. All
55 options apply ONLY to the next input or output file and are reset between files.
59 To set the video bitrate of the output file to 64kbit/s:
61 avconv -i input.avi -b 64k output.avi
65 To force the frame rate of the output file to 24 fps:
67 avconv -i input.avi -r 24 output.avi
71 To force the frame rate of the input file (valid for raw formats only)
72 to 1 fps and the frame rate of the output file to 24 fps:
74 avconv -r 1 -i input.m2v -r 24 output.avi
78 The format option may be needed for raw input files.
80 @c man end DESCRIPTION
82 @chapter Stream selection
83 @c man begin STREAM SELECTION
85 By default avconv tries to pick the "best" stream of each type present in input
86 files and add them to each output file. For video, this means the highest
87 resolution, for audio the highest channel count. For subtitle it's simply the
88 first subtitle stream.
90 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
91 full manual control, use the @code{-map} option, which disables the defaults just
94 @c man end STREAM SELECTION
99 @include avtools-common-opts.texi
101 @section Main options
105 @item -f @var{fmt} (@emph{input/output})
106 Force input or output file format. The format is normally autodetected for input
107 files and guessed from file extension for output files, so this option is not
108 needed in most cases.
110 @item -i @var{filename} (@emph{input})
113 @item -y (@emph{global})
114 Overwrite output files without asking.
116 @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
117 @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
118 Select an encoder (when used before an output file) or a decoder (when used
119 before an input file) for one or more streams. @var{codec} is the name of a
120 decoder/encoder or a special value @code{copy} (output only) to indicate that
121 the stream is not to be reencoded.
125 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
127 encodes all video streams with libx264 and copies all audio streams.
129 For each stream, the last matching @code{c} option is applied, so
131 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
133 will copy all the streams except the second video, which will be encoded with
134 libx264, and the 138th audio, which will be encoded with libvorbis.
136 @item -t @var{duration} (@emph{output})
137 Stop writing the output after its duration reaches @var{duration}.
138 @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
140 @item -fs @var{limit_size} (@emph{output})
141 Set the file size limit.
143 @item -ss @var{position} (@emph{input/output})
144 When used as an input option (before @code{-i}), seeks in this input file to
145 @var{position}. When used as an output option (before an output filename),
146 decodes but discards input until the timestamps reach @var{position}. This is
147 slower, but more accurate.
149 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
151 @item -itsoffset @var{offset} (@emph{input})
152 Set the input time offset in seconds.
153 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
154 The offset is added to the timestamps of the input files.
155 Specifying a positive offset means that the corresponding
156 streams are delayed by @var{offset} seconds.
158 @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
159 Set a metadata key/value pair.
161 An optional @var{metadata_specifier} may be given to set metadata
162 on streams or chapters. See @code{-map_metadata} documentation for
165 This option overrides metadata set with @code{-map_metadata}. It is
166 also possible to delete metadata by using an empty value.
168 For example, for setting the title in the output file:
170 avconv -i in.avi -metadata title="my title" out.flv
173 To set the language of the second stream:
175 avconv -i INPUT -metadata:s:1 language=eng OUTPUT
178 @item -target @var{type} (@emph{output})
179 Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
180 @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
181 @code{film-} to use the corresponding standard. All the format options
182 (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
185 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
188 Nevertheless you can specify additional options as long as you know
189 they do not conflict with the standard, as in:
192 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
195 @item -dframes @var{number} (@emph{output})
196 Set the number of data frames to record. This is an alias for @code{-frames:d}.
198 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
199 Stop writing to the stream after @var{framecount} frames.
201 @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
202 @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
203 Use fixed quality scale (VBR). The meaning of @var{q} is
206 @item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
207 @var{filter_graph} is a description of the filter graph to apply to
208 the stream. Use @code{-filters} to show all the available filters
209 (including also sources and sinks).
210 @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
211 Specify the preset for matching stream(s).
213 @item -stats (@emph{global})
214 Print encoding progress/statistics. On by default.
216 @item -attach @var{filename} (@emph{output})
217 Add an attachment to the output file. This is supported by a few formats
218 like Matroska for e.g. fonts used in rendering subtitles. Attachments
219 are implemented as a specific type of stream, so this option will add
220 a new stream to the file. It is then possible to use per-stream options
221 on this stream in the usual way. Attachment streams created with this
222 option will be created after all the other streams (i.e. those created
223 with @code{-map} or automatic mappings).
225 Note that for Matroska you also have to set the mimetype metadata tag:
227 avconv -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
229 (assuming that the attachment stream will be third in the output file).
231 @item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
232 Extract the matching attachment stream into a file named @var{filename}. If
233 @var{filename} is empty, then the value of the @code{filename} metadata tag
236 E.g. to extract the first attachment to a file named 'out.ttf':
238 avconv -dump_attachment:t:0 out.ttf INPUT
240 To extract all attachments to files determined by the @code{filename} tag:
242 avconv -dump_attachment:t "" INPUT
245 Technical note -- attachments are implemented as codec extradata, so this
246 option can actually be used to extract extradata from any stream, not just
251 @section Video Options
254 @item -vframes @var{number} (@emph{output})
255 Set the number of video frames to record. This is an alias for @code{-frames:v}.
256 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
257 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
258 @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
259 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
260 The following abbreviations are recognized:
322 @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
323 Set the video display aspect ratio specified by @var{aspect}.
325 @var{aspect} can be a floating point number string, or a string of the
326 form @var{num}:@var{den}, where @var{num} and @var{den} are the
327 numerator and denominator of the aspect ratio. For example "4:3",
328 "16:9", "1.3333", and "1.7777" are valid argument values.
330 @item -vn (@emph{output})
331 Disable video recording.
332 @item -bt @var{tolerance}
333 Set video bitrate tolerance (in bits, default 4000k).
334 Has a minimum value of: (target_bitrate/target_framerate).
335 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
336 willing to deviate from the target average bitrate value. This is
337 not related to min/max bitrate. Lowering tolerance too much has
338 an adverse effect on quality.
339 @item -maxrate @var{bitrate}
340 Set max video bitrate (in bit/s).
341 Requires -bufsize to be set.
342 @item -minrate @var{bitrate}
343 Set min video bitrate (in bit/s).
344 Most useful in setting up a CBR encode:
346 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
348 It is of little use elsewise.
349 @item -bufsize @var{size}
350 Set video buffer verifier buffer size (in bits).
351 @item -vcodec @var{codec} (@emph{output})
352 Set the video codec. This is an alias for @code{-codec:v}.
354 Use same quantizer as source (implies VBR).
356 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
360 Select the pass number (1 or 2). It is used to do two-pass
361 video encoding. The statistics of the video are recorded in the first
362 pass into a log file (see also the option -passlogfile),
363 and in the second pass that log file is used to generate the video
364 at the exact requested bitrate.
365 On pass 1, you may just deactivate audio and set output to null,
366 examples for Windows and Unix:
368 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
369 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
372 @item -passlogfile @var{prefix} (@emph{global})
373 Set two-pass log file name prefix to @var{prefix}, the default file name
374 prefix is ``av2pass''. The complete file name will be
375 @file{PREFIX-N.log}, where N is a number specific to the output
378 @item -vf @var{filter_graph} (@emph{output})
379 @var{filter_graph} is a description of the filter graph to apply to
381 Use the option "-filters" to show all the available filters (including
382 also sources and sinks). This is an alias for @code{-filter:v}.
386 @section Advanced Video Options
389 @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
390 Set pixel format. Use @code{-pix_fmts} to show all the supported
392 @item -sws_flags @var{flags} (@emph{input/output})
394 @item -g @var{gop_size}
395 Set the group of pictures size.
399 minimum video quantizer scale (VBR)
401 maximum video quantizer scale (VBR)
403 maximum difference between the quantizer scales (VBR)
404 @item -qblur @var{blur}
405 video quantizer scale blur (VBR) (range 0.0 - 1.0)
406 @item -qcomp @var{compression}
407 video quantizer scale compression (VBR) (default 0.5).
408 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
410 @item -lmin @var{lambda}
411 minimum video lagrange factor (VBR)
412 @item -lmax @var{lambda}
413 max video lagrange factor (VBR)
414 @item -mblmin @var{lambda}
415 minimum macroblock quantizer scale (VBR)
416 @item -mblmax @var{lambda}
417 maximum macroblock quantizer scale (VBR)
419 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
420 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
422 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
425 @item -rc_init_cplx @var{complexity}
426 initial complexity for single pass encoding
427 @item -b_qfactor @var{factor}
428 qp factor between P- and B-frames
429 @item -i_qfactor @var{factor}
430 qp factor between P- and I-frames
431 @item -b_qoffset @var{offset}
432 qp offset between P- and B-frames
433 @item -i_qoffset @var{offset}
434 qp offset between P- and I-frames
435 @item -rc_eq @var{equation}
436 Set rate control equation (see section "Expression Evaluation")
437 (default = @code{tex^qComp}).
439 When computing the rate control equation expression, besides the
440 standard functions defined in the section "Expression Evaluation", the
441 following functions are available:
447 and the following constants are available:
469 @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
470 rate control override for specific intervals
471 @item -me_method @var{method}
472 Set motion estimation method to @var{method}.
473 Available methods are (from lowest to best quality):
476 Try just the (0, 0) vector.
485 exhaustive search (slow and marginally better than epzs)
489 Set error resilience to @var{n}.
492 FF_ER_CAREFUL (default)
498 FF_ER_VERY_AGGRESSIVE
501 @item -ec @var{bit_mask}
502 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
503 the following values:
506 FF_EC_GUESS_MVS (default = enabled)
508 FF_EC_DEBLOCK (default = enabled)
511 @item -bf @var{frames}
512 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
513 @item -mbd @var{mode}
517 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
519 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
521 FF_MB_DECISION_RD: rate distortion
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.
530 Deinterlace pictures.
532 Dump video coding statistics to @file{vstats_HHMMSS.log}.
533 @item -vstats_file @var{file}
534 Dump video coding statistics to @var{file}.
535 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
536 top=1/bottom=0/auto=-1 field first
537 @item -dc @var{precision}
539 @item -vtag @var{fourcc/tag} (@emph{output})
540 Force video tag/fourcc. This is an alias for @code{-tag:v}.
541 @item -qphist (@emph{global})
543 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
544 Force key frames at the specified timestamps, more precisely at the first
545 frames after each specified time.
546 This option can be useful to ensure that a seek point is present at a
547 chapter mark or any other designated place in the output file.
548 The timestamps must be specified in ascending order.
550 @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
551 When doing stream copy, copy also non-key frames found at the
555 @section Audio Options
558 @item -aframes @var{number} (@emph{output})
559 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
560 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
561 Set the audio sampling frequency. For output streams it is set by
562 default to the frequency of the corresponding input stream. For input
563 streams this option only makes sense for audio grabbing devices and raw
564 demuxers and is mapped to the corresponding demuxer options.
565 @item -aq @var{q} (@emph{output})
566 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
567 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
568 Set the number of audio channels. For output streams it is set by
569 default to the number of input audio channels. For input streams
570 this option only makes sense for audio grabbing devices and raw demuxers
571 and is mapped to the corresponding demuxer options.
572 @item -an (@emph{output})
573 Disable audio recording.
574 @item -acodec @var{codec} (@emph{input/output})
575 Set the audio codec. This is an alias for @code{-codec:a}.
576 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
577 Set the audio sample format. Use @code{-sample_fmts} to get a list
578 of supported sample formats.
581 @section Advanced Audio options:
584 @item -atag @var{fourcc/tag} (@emph{output})
585 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
586 @item -audio_service_type @var{type}
587 Set the type of service that the audio stream contains.
590 Main Audio Service (default)
610 @section Subtitle options:
613 @item -scodec @var{codec} (@emph{input/output})
614 Set the subtitle codec. This is an alias for @code{-codec:s}.
615 @item -sn (@emph{output})
616 Disable subtitle recording.
619 @section Audio/Video grab options
622 @item -isync (@emph{global})
623 Synchronize read on input.
626 @section Advanced options
629 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output})
631 Designate one or more input streams as a source for the output file. Each input
632 stream is identified by the input file index @var{input_file_id} and
633 the input stream index @var{input_stream_id} within the input
634 file. Both indices start at 0. If specified,
635 @var{sync_file_id}:@var{stream_specifier} sets which input stream
636 is used as a presentation sync reference.
638 The first @code{-map} option on the command line specifies the
639 source for output stream 0, the second @code{-map} option specifies
640 the source for output stream 1, etc.
642 A @code{-} character before the stream identifier creates a "negative" mapping.
643 It disables matching streams from already created mappings.
645 For example, to map ALL streams from the first input file to output
647 avconv -i INPUT -map 0 output
650 For example, if you have two audio streams in the first input file,
651 these streams are identified by "0:0" and "0:1". You can use
652 @code{-map} to select which streams to place in an output file. For
655 avconv -i INPUT -map 0:1 out.wav
657 will map the input stream in @file{INPUT} identified by "0:1" to
658 the (single) output stream in @file{out.wav}.
660 For example, to select the stream with index 2 from input file
661 @file{a.mov} (specified by the identifier "0:2"), and stream with
662 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
663 and copy them to the output file @file{out.mov}:
665 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
668 To select all video and the third audio stream from an input file:
670 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
673 To map all the streams except the second audio, use negative mappings
675 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
678 Note that using this option disables the default mappings for this output file.
680 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] (@emph{output,per-metadata})
681 Set metadata information of the next output file from @var{infile}. Note that
682 those are file indices (zero-based), not filenames.
683 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
684 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
685 per-(p)rogram. All metadata specifiers other than global must be followed by the
686 stream/chapter/program index. If metadata specifier is omitted, it defaults to
689 By default, global metadata is copied from the first input file,
690 per-stream and per-chapter metadata is copied along with streams/chapters. These
691 default mappings are disabled by creating any mapping of the relevant type. A negative
692 file index can be used to create a dummy mapping that just disables automatic copying.
694 For example to copy metadata from the first stream of the input file to global metadata
697 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
699 @item -map_chapters @var{input_file_index} (@emph{output})
700 Copy chapters from input file with index @var{input_file_index} to the next
701 output file. If no chapter mapping is specified, then chapters are copied from
702 the first input file with at least one chapter. Use a negative file index to
703 disable any chapter copying.
705 Print specific debug info.
706 @item -benchmark (@emph{global})
707 Show benchmarking information at the end of an encode.
708 Shows CPU time used and maximum memory consumption.
709 Maximum memory consumption is not supported on all systems,
710 it will usually display as 0 if not supported.
711 @item -timelimit @var{duration} (@emph{global})
712 Exit after avconv has been running for @var{duration} seconds.
713 @item -dump (@emph{global})
714 Dump each input packet to stderr.
715 @item -hex (@emph{global})
716 When dumping packets, also dump the payload.
718 Set RTP payload size in bytes.
719 @item -re (@emph{input})
720 Read input at native frame rate. Mainly used to simulate a grab device.
721 @item -threads @var{count}
723 @item -vsync @var{parameter}
728 Each frame is passed with its timestamp from the demuxer to the muxer.
730 Frames will be duplicated and dropped to achieve exactly the requested
733 Frames are passed through with their timestamp or dropped so as to
734 prevent 2 frames from having the same timestamp.
736 Chooses between 1 and 2 depending on muxer capabilities. This is the
740 With -map you can select from which stream the timestamps should be
741 taken. You can leave either video or audio unchanged and sync the
742 remaining stream(s) to the unchanged one.
744 @item -async @var{samples_per_second}
745 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
746 the parameter is the maximum samples per second by which the audio is changed.
747 -async 1 is a special case where only the start of the audio stream is corrected
748 without any later correction.
750 Copy timestamps from input to output.
752 Copy input stream time base from input to output when stream copying.
754 Finish encoding when the shortest input stream ends.
755 @item -dts_delta_threshold
756 Timestamp discontinuity delta threshold.
757 @item -muxdelay @var{seconds} (@emph{input})
758 Set the maximum demux-decode delay.
759 @item -muxpreload @var{seconds} (@emph{input})
760 Set the initial demux-decode delay.
761 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
762 Assign a new stream-id value to an output stream. This option should be
763 specified prior to the output filename to which it applies.
764 For the situation where multiple output files exist, a streamid
765 may be reassigned to a different value.
767 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
768 an output mpegts file:
770 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
773 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
774 Set bitstream filters for matching streams. @var{bistream_filters} is
775 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
776 to get the list of bitstream filters.
778 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
781 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
784 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{output,per-stream})
785 Force a tag/fourcc for matching streams.
794 For streaming at very low bitrate application, use a low frame rate
795 and a small GOP size. This is especially true for RealVideo where
796 the Linux player does not seem to be very fast, so it can miss
797 frames. An example is:
800 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
804 The parameter 'q' which is displayed while encoding is the current
805 quantizer. The value 1 indicates that a very good quality could
806 be achieved. The value 31 indicates the worst quality. If q=31 appears
807 too often, it means that the encoder cannot compress enough to meet
808 your bitrate. You must either increase the bitrate, decrease the
809 frame rate or decrease the frame size.
812 If your computer is not fast enough, you can speed up the
813 compression at the expense of the compression ratio. You can use
814 '-me zero' to speed up motion estimation, and '-intra' to disable
815 motion estimation completely (you have only I-frames, which means it
816 is about as good as JPEG compression).
819 To have very low audio bitrates, reduce the sampling frequency
820 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
823 To have a constant quality (but a variable bitrate), use the option
824 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
831 @c man begin EXAMPLES
833 @section Preset files
835 A preset file contains a sequence of @var{option=value} pairs, one for
836 each line, specifying a sequence of options which can be specified also on
837 the command line. Lines starting with the hash ('#') character are ignored and
838 are used to provide comments. Empty lines are also ignored. Check the
839 @file{presets} directory in the Libav source tree for examples.
841 Preset files are specified with the @code{pre} option, this option takes a
842 preset name as input. Avconv searches for a file named @var{preset_name}.avpreset in
843 the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.avconv}, and in
844 the data directory defined at configuration time (usually @file{$PREFIX/share/avconv})
845 in that order. For example, if the argument is @code{libx264-max}, it will
846 search for the file @file{libx264-max.avpreset}.
848 @section Video and Audio grabbing
850 If you specify the input format and device then avconv can grab video
854 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
857 Note that you must activate the right video source and channel before
858 launching avconv with any TV viewer such as
859 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
860 have to set the audio recording levels correctly with a
863 @section X11 grabbing
865 Grab the X11 display with avconv via
868 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
871 0.0 is display.screen number of your X11 server, same as
872 the DISPLAY environment variable.
875 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
878 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
879 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
881 @section Video and Audio file format conversion
883 Any supported file format and protocol can serve as input to avconv:
888 You can use YUV files as input:
891 avconv -i /tmp/test%d.Y /tmp/out.mpg
894 It will use the files:
896 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
897 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
900 The Y files use twice the resolution of the U and V files. They are
901 raw files, without header. They can be generated by all decent video
902 decoders. You must specify the size of the image with the @option{-s} option
903 if avconv cannot guess it.
906 You can input from a raw YUV420P file:
909 avconv -i /tmp/test.yuv /tmp/out.avi
912 test.yuv is a file containing raw YUV planar data. Each frame is composed
913 of the Y plane followed by the U and V planes at half vertical and
914 horizontal resolution.
917 You can output to a raw YUV420P file:
920 avconv -i mydivx.avi hugefile.yuv
924 You can set several input files and output files:
927 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
930 Converts the audio file a.wav and the raw YUV video file a.yuv
934 You can also do audio and video conversions at the same time:
937 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
940 Converts a.wav to MPEG audio at 22050 Hz sample rate.
943 You can encode to several formats at the same time and define a
944 mapping from input stream to output streams:
947 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
950 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
951 file:index' specifies which input stream is used for each output
952 stream, in the order of the definition of output streams.
955 You can transcode decrypted VOBs:
958 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
961 This is a typical DVD ripping example; the input is a VOB file, the
962 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
963 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
964 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
965 input video. Furthermore, the audio stream is MP3-encoded so you need
966 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
967 The mapping is particularly useful for DVD transcoding
968 to get the desired audio language.
970 NOTE: To see the supported input formats, use @code{avconv -formats}.
973 You can extract images from a video, or create a video from many images:
975 For extracting images from a video:
977 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
980 This will extract one video frame per second from the video and will
981 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
982 etc. Images will be rescaled to fit the new WxH values.
984 If you want to extract just a limited number of frames, you can use the
985 above command in combination with the -vframes or -t option, or in
986 combination with -ss to start extracting from a certain point in time.
988 For creating a video from many images:
990 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
993 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
994 composed of three digits padded with zeroes to express the sequence
995 number. It is the same syntax supported by the C printf function, but
996 only formats accepting a normal integer are suitable.
999 You can put many streams of the same type in the output:
1002 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1005 The resulting output file @file{test12.avi} will contain first four streams from
1006 the input file in reverse order.
1012 @include encoders.texi
1013 @include demuxers.texi
1014 @include muxers.texi
1015 @include indevs.texi
1016 @include outdevs.texi
1017 @include protocols.texi
1018 @include bitstream_filters.texi
1019 @include filters.texi
1020 @include metadata.texi
1025 @settitle avconv video converter
1027 @c man begin SEEALSO
1028 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1031 @c man begin AUTHORS
1032 The Libav developers