1 \input texinfo @c -*- texinfo -*-
3 @settitle avconv Documentation
5 @center @titlefont{avconv Documentation}
14 The generic syntax is:
18 avconv [[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 The command line interface is designed to be intuitive, in the sense
30 that avconv tries to figure out all parameters that can possibly be
31 derived automatically. You usually only have to specify the target
34 As a general rule, options are applied to the next specified
35 file. Therefore, order is important, and you can have the same
36 option on the command line multiple times. Each occurrence is
37 then applied to the next input or output file.
41 To set the video bitrate of the output file to 64kbit/s:
43 avconv -i input.avi -b 64k output.avi
47 To force the frame rate of the output file to 24 fps:
49 avconv -i input.avi -r 24 output.avi
53 To force the frame rate of the input file (valid for raw formats only)
54 to 1 fps and the frame rate of the output file to 24 fps:
56 avconv -r 1 -i input.m2v -r 24 output.avi
60 The format option may be needed for raw input files.
62 By default avconv tries to convert as losslessly as possible: It
63 uses the same audio and video parameters for the outputs as the one
64 specified for the inputs.
66 @c man end DESCRIPTION
68 @chapter Stream selection
69 @c man begin STREAM SELECTION
71 By default avconv tries to pick the "best" stream of each type present in input
72 files and add them to each output file. For video, this means the highest
73 resolution, for audio the highest channel count. For subtitle it's simply the
74 first subtitle stream.
76 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
77 full manual control, use the @code{-map} option, which disables the defaults just
80 @c man end STREAM SELECTION
85 @include avtools-common-opts.texi
94 @item -i @var{filename}
98 Overwrite output files.
100 @item -c[:@var{stream_type}][:@var{stream_index}] @var{codec}
101 @item -codec[:@var{stream_type}][:@var{stream_index}] @var{codec}
102 Select an encoder (when used before an output file) or a decoder (when used
103 before an input file) for one or more streams. @var{codec} is the name of a
104 decoder/encoder or a special value @code{copy} (output only) to indicate that
105 the stream is not to be reencoded.
107 @var{stream_type} may be 'v' for video, 'a' for audio, 's' for subtitle and 'd'
108 for data streams. @var{stream_index} is a global zero-based stream index if
109 @var{stream_type} isn't given, otherwise it counts only streams of the given
110 type. If @var{stream_index} is omitted, this option applies to all streams of
111 the given type or all streams of any type if @var{stream_type} is missing as
112 well (note that this only makes sense when all streams are of the same type or
113 @var{codec} is @code{copy}).
117 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
119 encodes all video streams with libx264 and copies all audio streams.
121 For each stream, the last matching @code{c} option is applied, so
123 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
125 will copy all the streams except the second video, which will be encoded with
126 libx264, and the 138th audio, which will be encoded with libvorbis.
128 @item -t @var{duration}
129 Restrict the transcoded/captured video sequence
130 to the duration specified in seconds.
131 @code{hh:mm:ss[.xxx]} syntax is also supported.
133 @item -fs @var{limit_size}
134 Set the file size limit.
136 @item -ss @var{position}
137 When used as an input option (before @code{-i}), seeks in this input file to
138 @var{position}. When used as an output option (before an output filename),
139 decodes but discards input until the timestamps reach @var{position}. This is
140 slower, but more accurate.
142 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
144 @item -itsoffset @var{offset}
145 Set the input time offset in seconds.
146 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
147 The offset is added to the timestamps of the input files.
148 Specifying a positive offset means that the corresponding
149 streams are delayed by 'offset' seconds.
151 @item -timestamp @var{time}
152 Set the recording timestamp in the container.
153 The syntax for @var{time} is:
155 now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
157 If the value is "now" it takes the current time.
158 Time is local time unless 'Z' or 'z' is appended, in which case it is
160 If the year-month-day part is not specified it takes the current
163 @item -metadata[:metadata_specifier] @var{key}=@var{value}
164 Set a metadata key/value pair.
166 An optional @var{metadata_specifier} may be given to set metadata
167 on streams or chapters. See @code{-map_metadata} documentation for
170 This option overrides metadata set with @code{-map_metadata}. It is
171 also possible to delete metadata by using an empty value.
173 For example, for setting the title in the output file:
175 avconv -i in.avi -metadata title="my title" out.flv
178 To set the language of the second stream:
180 avconv -i INPUT -metadata:s:1 language=eng OUTPUT
183 @item -v @var{number}
184 Set the logging verbosity level.
186 @item -target @var{type}
187 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
188 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
189 buffer sizes) are then set automatically. You can just type:
192 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
195 Nevertheless you can specify additional options as long as you know
196 they do not conflict with the standard, as in:
199 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
202 @item -dframes @var{number}
203 Set the number of data frames to record. This is an alias for @code{-frames:d}.
205 @item -frames[:stream_specifier] @var{framecount}
206 Stop writing to the stream after @var{framecount} frames.
209 @item -qscale @var{q}
210 Use fixed quality scale (VBR). The meaning of @var{q} is
213 @item -filter[:stream_specifier] @var{filter_graph}
214 @var{filter_graph} is a description of the filter graph to apply to
215 the stream. Use @code{-filters} to show all the available filters
216 (including also sources and sinks).
220 @section Video Options
223 @item -vframes @var{number}
224 Set the number of video frames to record. This is an alias for @code{-frames:v}.
226 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
228 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
229 The following abbreviations are recognized:
291 @item -aspect @var{aspect}
292 Set the video display aspect ratio specified by @var{aspect}.
294 @var{aspect} can be a floating point number string, or a string of the
295 form @var{num}:@var{den}, where @var{num} and @var{den} are the
296 numerator and denominator of the aspect ratio. For example "4:3",
297 "16:9", "1.3333", and "1.7777" are valid argument values.
300 Disable video recording.
301 @item -bt @var{tolerance}
302 Set video bitrate tolerance (in bits, default 4000k).
303 Has a minimum value of: (target_bitrate/target_framerate).
304 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
305 willing to deviate from the target average bitrate value. This is
306 not related to min/max bitrate. Lowering tolerance too much has
307 an adverse effect on quality.
308 @item -maxrate @var{bitrate}
309 Set max video bitrate (in bit/s).
310 Requires -bufsize to be set.
311 @item -minrate @var{bitrate}
312 Set min video bitrate (in bit/s).
313 Most useful in setting up a CBR encode:
315 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
317 It is of little use elsewise.
318 @item -bufsize @var{size}
319 Set video buffer verifier buffer size (in bits).
320 @item -vcodec @var{codec}
321 Set the video codec. This is an alias for @code{-codec:v}.
323 Use same quantizer as source (implies VBR).
325 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
329 Select the pass number (1 or 2). It is used to do two-pass
330 video encoding. The statistics of the video are recorded in the first
331 pass into a log file (see also the option -passlogfile),
332 and in the second pass that log file is used to generate the video
333 at the exact requested bitrate.
334 On pass 1, you may just deactivate audio and set output to null,
335 examples for Windows and Unix:
337 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
338 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
341 @item -passlogfile @var{prefix}
342 Set two-pass log file name prefix to @var{prefix}, the default file name
343 prefix is ``av2pass''. The complete file name will be
344 @file{PREFIX-N.log}, where N is a number specific to the output
347 @item -vf @var{filter_graph}
348 @var{filter_graph} is a description of the filter graph to apply to
350 Use the option "-filters" to show all the available filters (including
351 also sources and sinks). This is an alias for @code{-filter:v}.
355 @section Advanced Video Options
358 @item -pix_fmt @var{format}
359 Set pixel format. Use @code{-pix_fmts} to show all the supported
361 @item -sws_flags @var{flags}
363 @item -g @var{gop_size}
364 Set the group of pictures size.
368 minimum video quantizer scale (VBR)
370 maximum video quantizer scale (VBR)
372 maximum difference between the quantizer scales (VBR)
373 @item -qblur @var{blur}
374 video quantizer scale blur (VBR) (range 0.0 - 1.0)
375 @item -qcomp @var{compression}
376 video quantizer scale compression (VBR) (default 0.5).
377 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
379 @item -lmin @var{lambda}
380 minimum video lagrange factor (VBR)
381 @item -lmax @var{lambda}
382 max video lagrange factor (VBR)
383 @item -mblmin @var{lambda}
384 minimum macroblock quantizer scale (VBR)
385 @item -mblmax @var{lambda}
386 maximum macroblock quantizer scale (VBR)
388 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
389 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
391 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
394 @item -rc_init_cplx @var{complexity}
395 initial complexity for single pass encoding
396 @item -b_qfactor @var{factor}
397 qp factor between P- and B-frames
398 @item -i_qfactor @var{factor}
399 qp factor between P- and I-frames
400 @item -b_qoffset @var{offset}
401 qp offset between P- and B-frames
402 @item -i_qoffset @var{offset}
403 qp offset between P- and I-frames
404 @item -rc_eq @var{equation}
405 Set rate control equation (see section "Expression Evaluation")
406 (default = @code{tex^qComp}).
408 When computing the rate control equation expression, besides the
409 standard functions defined in the section "Expression Evaluation", the
410 following functions are available:
416 and the following constants are available:
438 @item -rc_override @var{override}
439 rate control override for specific intervals
440 @item -me_method @var{method}
441 Set motion estimation method to @var{method}.
442 Available methods are (from lowest to best quality):
445 Try just the (0, 0) vector.
454 exhaustive search (slow and marginally better than epzs)
457 @item -dct_algo @var{algo}
458 Set DCT algorithm to @var{algo}. Available values are:
461 FF_DCT_AUTO (default)
474 @item -idct_algo @var{algo}
475 Set IDCT algorithm to @var{algo}. Available values are:
478 FF_IDCT_AUTO (default)
502 Set error resilience to @var{n}.
505 FF_ER_CAREFUL (default)
511 FF_ER_VERY_AGGRESSIVE
514 @item -ec @var{bit_mask}
515 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
516 the following values:
519 FF_EC_GUESS_MVS (default = enabled)
521 FF_EC_DEBLOCK (default = enabled)
524 @item -bf @var{frames}
525 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
526 @item -mbd @var{mode}
530 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
532 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
534 FF_MB_DECISION_RD: rate distortion
538 Use four motion vector by macroblock (MPEG-4 only).
540 Use data partitioning (MPEG-4 only).
541 @item -bug @var{param}
542 Work around encoder bugs that are not auto-detected.
543 @item -strict @var{strictness}
544 How strictly to follow the standards.
546 Enable Advanced intra coding (h263+).
548 Enable Unlimited Motion Vector (h263+)
551 Deinterlace pictures.
553 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
554 Use this option if your input file is interlaced and you want
555 to keep the interlaced format for minimum losses.
556 The alternative is to deinterlace the input stream with
557 @option{-deinterlace}, but deinterlacing introduces losses.
559 Dump video coding statistics to @file{vstats_HHMMSS.log}.
560 @item -vstats_file @var{file}
561 Dump video coding statistics to @var{file}.
563 top=1/bottom=0/auto=-1 field first
564 @item -dc @var{precision}
566 @item -vtag @var{fourcc/tag}
567 Force video tag/fourcc. This is an alias for @code{-tag:v}.
570 @item -force_key_frames @var{time}[,@var{time}...]
571 Force key frames at the specified timestamps, more precisely at the first
572 frames after each specified time.
573 This option can be useful to ensure that a seek point is present at a
574 chapter mark or any other designated place in the output file.
575 The timestamps must be specified in ascending order.
578 @section Audio Options
581 @item -aframes @var{number}
582 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
584 Set the audio sampling frequency. For output streams it is set by
585 default to the frequency of the corresponding input stream. For input
586 streams this option only makes sense for audio grabbing devices and raw
587 demuxers and is mapped to the corresponding demuxer options.
589 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
590 @item -ac @var{channels}
591 Set the number of audio channels. For output streams it is set by
592 default to the number of input audio channels. For input streams
593 this option only makes sense for audio grabbing devices and raw demuxers
594 and is mapped to the corresponding demuxer options.
596 Disable audio recording.
597 @item -acodec @var{codec}
598 Set the audio codec. This is an alias for @code{-codec:a}.
599 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt}
600 Set the audio sample format. Use @code{-help sample_fmts} to get a list
601 of supported sample formats.
604 @section Advanced Audio options:
607 @item -atag @var{fourcc/tag}
608 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
609 @item -audio_service_type @var{type}
610 Set the type of service that the audio stream contains.
613 Main Audio Service (default)
633 @section Subtitle options:
636 @item -scodec @var{codec}
637 Set the subtitle codec. This is an alias for @code{-codec:s}.
639 Disable subtitle recording.
642 @section Audio/Video grab options
646 Synchronize read on input.
649 @section Advanced options
652 @item -map [-]@var{input_file_id}[:@var{input_stream_type}][:@var{input_stream_id}][,@var{sync_file_id}[:@var{sync_stream_type}][:@var{sync_stream_id}]]
654 Designate one or more input streams as a source for the output file. Each input
655 stream is identified by the input file index @var{input_file_id} and
656 the input stream index @var{input_stream_id} within the input
657 file. Both indices start at 0. If specified,
658 @var{sync_file_id}:@var{sync_stream_id} sets which input stream
659 is used as a presentation sync reference.
661 If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
662 subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
663 of this type. Same for @var{sync_stream_type}.
665 @var{input_stream_id} may be omitted, in which case all streams of the given
666 type are mapped (or all streams in the file, if no type is specified).
668 The first @code{-map} option on the command line specifies the
669 source for output stream 0, the second @code{-map} option specifies
670 the source for output stream 1, etc.
672 A @code{-} character before the stream identifier creates a "negative" mapping.
673 It disables matching streams from already created mappings.
675 For example, to map ALL streams from the first input file to output
677 avconv -i INPUT -map 0 output
680 For example, if you have two audio streams in the first input file,
681 these streams are identified by "0:0" and "0:1". You can use
682 @code{-map} to select which streams to place in an output file. For
685 avconv -i INPUT -map 0:1 out.wav
687 will map the input stream in @file{INPUT} identified by "0:1" to
688 the (single) output stream in @file{out.wav}.
690 For example, to select the stream with index 2 from input file
691 @file{a.mov} (specified by the identifier "0:2"), and stream with
692 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
693 and copy them to the output file @file{out.mov}:
695 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
698 To select all video and the third audio stream from an input file:
700 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
703 To map all the streams except the second audio, use negative mappings
705 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
708 Note that using this option disables the default mappings for this output file.
710 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
711 Set metadata information of the next output file from @var{infile}. Note that
712 those are file indices (zero-based), not filenames.
713 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
714 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
715 per-(p)rogram. All metadata specifiers other than global must be followed by the
716 stream/chapter/program index. If metadata specifier is omitted, it defaults to
719 By default, global metadata is copied from the first input file,
720 per-stream and per-chapter metadata is copied along with streams/chapters. These
721 default mappings are disabled by creating any mapping of the relevant type. A negative
722 file index can be used to create a dummy mapping that just disables automatic copying.
724 For example to copy metadata from the first stream of the input file to global metadata
727 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
729 @item -map_chapters @var{input_file_index}
730 Copy chapters from input file with index @var{input_file_index} to the next
731 output file. If no chapter mapping is specified, then chapters are copied from
732 the first input file with at least one chapter. Use a negative file index to
733 disable any chapter copying.
735 Print specific debug info.
737 Show benchmarking information at the end of an encode.
738 Shows CPU time used and maximum memory consumption.
739 Maximum memory consumption is not supported on all systems,
740 it will usually display as 0 if not supported.
742 Dump each input packet.
744 When dumping packets, also dump the payload.
746 Only use bit exact algorithms (for codec testing).
748 Set RTP payload size in bytes.
750 Read input at native frame rate. Mainly used to simulate a grab device.
751 @item -threads @var{count}
753 @item -vsync @var{parameter}
758 Each frame is passed with its timestamp from the demuxer to the muxer.
760 Frames will be duplicated and dropped to achieve exactly the requested
763 Frames are passed through with their timestamp or dropped so as to
764 prevent 2 frames from having the same timestamp.
766 Chooses between 1 and 2 depending on muxer capabilities. This is the
770 With -map you can select from which stream the timestamps should be
771 taken. You can leave either video or audio unchanged and sync the
772 remaining stream(s) to the unchanged one.
774 @item -async @var{samples_per_second}
775 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
776 the parameter is the maximum samples per second by which the audio is changed.
777 -async 1 is a special case where only the start of the audio stream is corrected
778 without any later correction.
780 Copy timestamps from input to output.
782 Copy input stream time base from input to output when stream copying.
784 Finish encoding when the shortest input stream ends.
785 @item -dts_delta_threshold
786 Timestamp discontinuity delta threshold.
787 @item -muxdelay @var{seconds}
788 Set the maximum demux-decode delay.
789 @item -muxpreload @var{seconds}
790 Set the initial demux-decode delay.
791 @item -streamid @var{output-stream-index}:@var{new-value}
792 Assign a new stream-id value to an output stream. This option should be
793 specified prior to the output filename to which it applies.
794 For the situation where multiple output files exist, a streamid
795 may be reassigned to a different value.
797 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
798 an output mpegts file:
800 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
803 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters}
804 Set bitstream filters for matching streams. @var{bistream_filters} is
805 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
806 to get the list of bitstream filters.
808 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
811 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
814 @item -tag[:@var{stream_specifier}] @var{codec_tag}
815 Force a tag/fourcc for matching streams.
824 For streaming at very low bitrate application, use a low frame rate
825 and a small GOP size. This is especially true for RealVideo where
826 the Linux player does not seem to be very fast, so it can miss
827 frames. An example is:
830 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
834 The parameter 'q' which is displayed while encoding is the current
835 quantizer. The value 1 indicates that a very good quality could
836 be achieved. The value 31 indicates the worst quality. If q=31 appears
837 too often, it means that the encoder cannot compress enough to meet
838 your bitrate. You must either increase the bitrate, decrease the
839 frame rate or decrease the frame size.
842 If your computer is not fast enough, you can speed up the
843 compression at the expense of the compression ratio. You can use
844 '-me zero' to speed up motion estimation, and '-intra' to disable
845 motion estimation completely (you have only I-frames, which means it
846 is about as good as JPEG compression).
849 To have very low audio bitrates, reduce the sampling frequency
850 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
853 To have a constant quality (but a variable bitrate), use the option
854 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
861 @c man begin EXAMPLES
863 @section Video and Audio grabbing
865 If you specify the input format and device then avconv can grab video
869 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
872 Note that you must activate the right video source and channel before
873 launching avconv with any TV viewer such as
874 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
875 have to set the audio recording levels correctly with a
878 @section X11 grabbing
880 Grab the X11 display with avconv via
883 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
886 0.0 is display.screen number of your X11 server, same as
887 the DISPLAY environment variable.
890 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
893 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
894 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
896 @section Video and Audio file format conversion
898 Any supported file format and protocol can serve as input to avconv:
903 You can use YUV files as input:
906 avconv -i /tmp/test%d.Y /tmp/out.mpg
909 It will use the files:
911 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
912 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
915 The Y files use twice the resolution of the U and V files. They are
916 raw files, without header. They can be generated by all decent video
917 decoders. You must specify the size of the image with the @option{-s} option
918 if avconv cannot guess it.
921 You can input from a raw YUV420P file:
924 avconv -i /tmp/test.yuv /tmp/out.avi
927 test.yuv is a file containing raw YUV planar data. Each frame is composed
928 of the Y plane followed by the U and V planes at half vertical and
929 horizontal resolution.
932 You can output to a raw YUV420P file:
935 avconv -i mydivx.avi hugefile.yuv
939 You can set several input files and output files:
942 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
945 Converts the audio file a.wav and the raw YUV video file a.yuv
949 You can also do audio and video conversions at the same time:
952 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
955 Converts a.wav to MPEG audio at 22050 Hz sample rate.
958 You can encode to several formats at the same time and define a
959 mapping from input stream to output streams:
962 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
965 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
966 file:index' specifies which input stream is used for each output
967 stream, in the order of the definition of output streams.
970 You can transcode decrypted VOBs:
973 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
976 This is a typical DVD ripping example; the input is a VOB file, the
977 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
978 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
979 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
980 input video. Furthermore, the audio stream is MP3-encoded so you need
981 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
982 The mapping is particularly useful for DVD transcoding
983 to get the desired audio language.
985 NOTE: To see the supported input formats, use @code{avconv -formats}.
988 You can extract images from a video, or create a video from many images:
990 For extracting images from a video:
992 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
995 This will extract one video frame per second from the video and will
996 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
997 etc. Images will be rescaled to fit the new WxH values.
999 If you want to extract just a limited number of frames, you can use the
1000 above command in combination with the -vframes or -t option, or in
1001 combination with -ss to start extracting from a certain point in time.
1003 For creating a video from many images:
1005 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1008 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1009 composed of three digits padded with zeroes to express the sequence
1010 number. It is the same syntax supported by the C printf function, but
1011 only formats accepting a normal integer are suitable.
1014 You can put many streams of the same type in the output:
1017 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1020 The resulting output file @file{test12.avi} will contain first four streams from
1021 the input file in reverse order.
1027 @include encoders.texi
1028 @include demuxers.texi
1029 @include muxers.texi
1030 @include indevs.texi
1031 @include outdevs.texi
1032 @include protocols.texi
1033 @include bitstream_filters.texi
1034 @include filters.texi
1035 @include metadata.texi
1040 @settitle avconv video converter
1042 @c man begin SEEALSO
1043 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1046 @c man begin AUTHORS
1047 The Libav developers