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 command line 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 first audio stream:
175 avconv -i INPUT -metadata:s:a:0 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} (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.
531 This option is deprecated since the deinterlacing is very low quality.
532 Use the yadif filter with @code{-filter:v yadif}.
534 Dump video coding statistics to @file{vstats_HHMMSS.log}.
535 @item -vstats_file @var{file}
536 Dump video coding statistics to @var{file}.
537 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
538 top=1/bottom=0/auto=-1 field first
539 @item -dc @var{precision}
541 @item -vtag @var{fourcc/tag} (@emph{output})
542 Force video tag/fourcc. This is an alias for @code{-tag:v}.
543 @item -qphist (@emph{global})
545 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
546 Force key frames at the specified timestamps, more precisely at the first
547 frames after each specified time.
548 This option can be useful to ensure that a seek point is present at a
549 chapter mark or any other designated place in the output file.
550 The timestamps must be specified in ascending order.
552 @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
553 When doing stream copy, copy also non-key frames found at the
557 @section Audio Options
560 @item -aframes @var{number} (@emph{output})
561 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
562 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
563 Set the audio sampling frequency. For output streams it is set by
564 default to the frequency of the corresponding input stream. For input
565 streams this option only makes sense for audio grabbing devices and raw
566 demuxers and is mapped to the corresponding demuxer options.
567 @item -aq @var{q} (@emph{output})
568 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
569 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
570 Set the number of audio channels. For output streams it is set by
571 default to the number of input audio channels. For input streams
572 this option only makes sense for audio grabbing devices and raw demuxers
573 and is mapped to the corresponding demuxer options.
574 @item -an (@emph{output})
575 Disable audio recording.
576 @item -acodec @var{codec} (@emph{input/output})
577 Set the audio codec. This is an alias for @code{-codec:a}.
578 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
579 Set the audio sample format. Use @code{-sample_fmts} to get a list
580 of supported sample formats.
583 @section Advanced Audio options:
586 @item -atag @var{fourcc/tag} (@emph{output})
587 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
588 @item -audio_service_type @var{type}
589 Set the type of service that the audio stream contains.
592 Main Audio Service (default)
612 @section Subtitle options:
615 @item -scodec @var{codec} (@emph{input/output})
616 Set the subtitle codec. This is an alias for @code{-codec:s}.
617 @item -sn (@emph{output})
618 Disable subtitle recording.
621 @section Audio/Video grab options
624 @item -isync (@emph{global})
625 Synchronize read on input.
628 @section Advanced options
631 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output})
633 Designate one or more input streams as a source for the output file. Each input
634 stream is identified by the input file index @var{input_file_id} and
635 the input stream index @var{input_stream_id} within the input
636 file. Both indices start at 0. If specified,
637 @var{sync_file_id}:@var{stream_specifier} sets which input stream
638 is used as a presentation sync reference.
640 The first @code{-map} option on the command line specifies the
641 source for output stream 0, the second @code{-map} option specifies
642 the source for output stream 1, etc.
644 A @code{-} character before the stream identifier creates a "negative" mapping.
645 It disables matching streams from already created mappings.
647 For example, to map ALL streams from the first input file to output
649 avconv -i INPUT -map 0 output
652 For example, if you have two audio streams in the first input file,
653 these streams are identified by "0:0" and "0:1". You can use
654 @code{-map} to select which streams to place in an output file. For
657 avconv -i INPUT -map 0:1 out.wav
659 will map the input stream in @file{INPUT} identified by "0:1" to
660 the (single) output stream in @file{out.wav}.
662 For example, to select the stream with index 2 from input file
663 @file{a.mov} (specified by the identifier "0:2"), and stream with
664 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
665 and copy them to the output file @file{out.mov}:
667 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
670 To select all video and the third audio stream from an input file:
672 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
675 To map all the streams except the second audio, use negative mappings
677 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
680 Note that using this option disables the default mappings for this output file.
682 @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
683 Set metadata information of the next output file from @var{infile}. Note that
684 those are file indices (zero-based), not filenames.
685 Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
686 A metadata specifier can have the following forms:
689 global metadata, i.e. metadata that applies to the whole file
691 @item @var{s}[:@var{stream_spec}]
692 per-stream metadata. @var{stream_spec} is a stream specifier as described
693 in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
694 matching stream is copied from. In an output metadata specifier, all matching
695 streams are copied to.
697 @item @var{c}:@var{chapter_index}
698 per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
700 @item @var{p}:@var{program_index}
701 per-program metadata. @var{program_index} is the zero-based program index.
703 If metadata specifier is omitted, it defaults to global.
705 By default, global metadata is copied from the first input file,
706 per-stream and per-chapter metadata is copied along with streams/chapters. These
707 default mappings are disabled by creating any mapping of the relevant type. A negative
708 file index can be used to create a dummy mapping that just disables automatic copying.
710 For example to copy metadata from the first stream of the input file to global metadata
713 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
716 To do the reverse, i.e. copy global metadata to all audio streams:
718 avconv -i in.mkv -map_metadata:s:a 0:g out.mkv
720 Note that simple @code{0} would work as well in this example, since global
721 metadata is assumed by default.
723 @item -map_chapters @var{input_file_index} (@emph{output})
724 Copy chapters from input file with index @var{input_file_index} to the next
725 output file. If no chapter mapping is specified, then chapters are copied from
726 the first input file with at least one chapter. Use a negative file index to
727 disable any chapter copying.
729 Print specific debug info.
730 @item -benchmark (@emph{global})
731 Show benchmarking information at the end of an encode.
732 Shows CPU time used and maximum memory consumption.
733 Maximum memory consumption is not supported on all systems,
734 it will usually display as 0 if not supported.
735 @item -timelimit @var{duration} (@emph{global})
736 Exit after avconv has been running for @var{duration} seconds.
737 @item -dump (@emph{global})
738 Dump each input packet to stderr.
739 @item -hex (@emph{global})
740 When dumping packets, also dump the payload.
742 Set RTP payload size in bytes.
743 @item -re (@emph{input})
744 Read input at native frame rate. Mainly used to simulate a grab device.
745 @item -threads @var{count}
747 @item -vsync @var{parameter}
752 Each frame is passed with its timestamp from the demuxer to the muxer.
754 Frames will be duplicated and dropped to achieve exactly the requested
757 Frames are passed through with their timestamp or dropped so as to
758 prevent 2 frames from having the same timestamp.
760 Chooses between 1 and 2 depending on muxer capabilities. This is the
764 With -map you can select from which stream the timestamps should be
765 taken. You can leave either video or audio unchanged and sync the
766 remaining stream(s) to the unchanged one.
768 @item -async @var{samples_per_second}
769 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
770 the parameter is the maximum samples per second by which the audio is changed.
771 -async 1 is a special case where only the start of the audio stream is corrected
772 without any later correction.
774 Copy timestamps from input to output.
776 Copy input stream time base from input to output when stream copying.
778 Finish encoding when the shortest input stream ends.
779 @item -dts_delta_threshold
780 Timestamp discontinuity delta threshold.
781 @item -muxdelay @var{seconds} (@emph{input})
782 Set the maximum demux-decode delay.
783 @item -muxpreload @var{seconds} (@emph{input})
784 Set the initial demux-decode delay.
785 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
786 Assign a new stream-id value to an output stream. This option should be
787 specified prior to the output filename to which it applies.
788 For the situation where multiple output files exist, a streamid
789 may be reassigned to a different value.
791 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
792 an output mpegts file:
794 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
797 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
798 Set bitstream filters for matching streams. @var{bistream_filters} is
799 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
800 to get the list of bitstream filters.
802 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
805 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
808 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{output,per-stream})
809 Force a tag/fourcc for matching streams.
818 For streaming at very low bitrate application, use a low frame rate
819 and a small GOP size. This is especially true for RealVideo where
820 the Linux player does not seem to be very fast, so it can miss
821 frames. An example is:
824 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
828 The parameter 'q' which is displayed while encoding is the current
829 quantizer. The value 1 indicates that a very good quality could
830 be achieved. The value 31 indicates the worst quality. If q=31 appears
831 too often, it means that the encoder cannot compress enough to meet
832 your bitrate. You must either increase the bitrate, decrease the
833 frame rate or decrease the frame size.
836 If your computer is not fast enough, you can speed up the
837 compression at the expense of the compression ratio. You can use
838 '-me zero' to speed up motion estimation, and '-intra' to disable
839 motion estimation completely (you have only I-frames, which means it
840 is about as good as JPEG compression).
843 To have very low audio bitrates, reduce the sampling frequency
844 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
847 To have a constant quality (but a variable bitrate), use the option
848 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
855 @c man begin EXAMPLES
857 @section Preset files
859 A preset file contains a sequence of @var{option=value} pairs, one for
860 each line, specifying a sequence of options which can be specified also on
861 the command line. Lines starting with the hash ('#') character are ignored and
862 are used to provide comments. Empty lines are also ignored. Check the
863 @file{presets} directory in the Libav source tree for examples.
865 Preset files are specified with the @code{pre} option, this option takes a
866 preset name as input. Avconv searches for a file named @var{preset_name}.avpreset in
867 the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.avconv}, and in
868 the data directory defined at configuration time (usually @file{$PREFIX/share/avconv})
869 in that order. For example, if the argument is @code{libx264-max}, it will
870 search for the file @file{libx264-max.avpreset}.
872 @section Video and Audio grabbing
874 If you specify the input format and device then avconv can grab video
878 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
881 Note that you must activate the right video source and channel before
882 launching avconv with any TV viewer such as
883 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
884 have to set the audio recording levels correctly with a
887 @section X11 grabbing
889 Grab the X11 display with avconv via
892 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
895 0.0 is display.screen number of your X11 server, same as
896 the DISPLAY environment variable.
899 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
902 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
903 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
905 @section Video and Audio file format conversion
907 Any supported file format and protocol can serve as input to avconv:
912 You can use YUV files as input:
915 avconv -i /tmp/test%d.Y /tmp/out.mpg
918 It will use the files:
920 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
921 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
924 The Y files use twice the resolution of the U and V files. They are
925 raw files, without header. They can be generated by all decent video
926 decoders. You must specify the size of the image with the @option{-s} option
927 if avconv cannot guess it.
930 You can input from a raw YUV420P file:
933 avconv -i /tmp/test.yuv /tmp/out.avi
936 test.yuv is a file containing raw YUV planar data. Each frame is composed
937 of the Y plane followed by the U and V planes at half vertical and
938 horizontal resolution.
941 You can output to a raw YUV420P file:
944 avconv -i mydivx.avi hugefile.yuv
948 You can set several input files and output files:
951 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
954 Converts the audio file a.wav and the raw YUV video file a.yuv
958 You can also do audio and video conversions at the same time:
961 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
964 Converts a.wav to MPEG audio at 22050 Hz sample rate.
967 You can encode to several formats at the same time and define a
968 mapping from input stream to output streams:
971 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
974 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
975 file:index' specifies which input stream is used for each output
976 stream, in the order of the definition of output streams.
979 You can transcode decrypted VOBs:
982 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
985 This is a typical DVD ripping example; the input is a VOB file, the
986 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
987 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
988 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
989 input video. Furthermore, the audio stream is MP3-encoded so you need
990 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
991 The mapping is particularly useful for DVD transcoding
992 to get the desired audio language.
994 NOTE: To see the supported input formats, use @code{avconv -formats}.
997 You can extract images from a video, or create a video from many images:
999 For extracting images from a video:
1001 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
1004 This will extract one video frame per second from the video and will
1005 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1006 etc. Images will be rescaled to fit the new WxH values.
1008 If you want to extract just a limited number of frames, you can use the
1009 above command in combination with the -vframes or -t option, or in
1010 combination with -ss to start extracting from a certain point in time.
1012 For creating a video from many images:
1014 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1017 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1018 composed of three digits padded with zeroes to express the sequence
1019 number. It is the same syntax supported by the C printf function, but
1020 only formats accepting a normal integer are suitable.
1023 You can put many streams of the same type in the output:
1026 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1029 The resulting output file @file{test12.avi} will contain first four streams from
1030 the input file in reverse order.
1036 @include encoders.texi
1037 @include demuxers.texi
1038 @include muxers.texi
1039 @include indevs.texi
1040 @include outdevs.texi
1041 @include protocols.texi
1042 @include bitstream_filters.texi
1043 @include filters.texi
1044 @include metadata.texi
1049 @settitle avconv video converter
1051 @c man begin SEEALSO
1052 avplay(1), avprobe(1) and the Libav HTML documentation
1055 @c man begin AUTHORS
1056 The Libav developers