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 fftools-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 @var{key}=@var{value}
164 Set a metadata key/value pair.
166 For example, for setting the title in the output file:
168 avconv -i in.avi -metadata title="my title" out.flv
171 @item -v @var{number}
172 Set the logging verbosity level.
174 @item -target @var{type}
175 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
176 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
177 buffer sizes) are then set automatically. You can just type:
180 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
183 Nevertheless you can specify additional options as long as you know
184 they do not conflict with the standard, as in:
187 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
190 @item -dframes @var{number}
191 Set the number of data frames to record.
193 @item -slang @var{code}
194 Set the ISO 639 language code (3 letters) of the current subtitle stream.
198 @section Video Options
201 @item -vframes @var{number}
202 Set the number of video frames to record.
204 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
206 Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source).
207 The following abbreviations are recognized:
269 @item -aspect @var{aspect}
270 Set the video display aspect ratio specified by @var{aspect}.
272 @var{aspect} can be a floating point number string, or a string of the
273 form @var{num}:@var{den}, where @var{num} and @var{den} are the
274 numerator and denominator of the aspect ratio. For example "4:3",
275 "16:9", "1.3333", and "1.7777" are valid argument values.
277 @item -croptop @var{size}
278 @item -cropbottom @var{size}
279 @item -cropleft @var{size}
280 @item -cropright @var{size}
281 All the crop options have been removed. Use -vf
282 crop=width:height:x:y instead.
284 @item -padtop @var{size}
285 @item -padbottom @var{size}
286 @item -padleft @var{size}
287 @item -padright @var{size}
288 @item -padcolor @var{hex_color}
289 All the pad options have been removed. Use -vf
290 pad=width:height:x:y:color instead.
292 Disable video recording.
293 @item -bt @var{tolerance}
294 Set video bitrate tolerance (in bits, default 4000k).
295 Has a minimum value of: (target_bitrate/target_framerate).
296 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
297 willing to deviate from the target average bitrate value. This is
298 not related to min/max bitrate. Lowering tolerance too much has
299 an adverse effect on quality.
300 @item -maxrate @var{bitrate}
301 Set max video bitrate (in bit/s).
302 Requires -bufsize to be set.
303 @item -minrate @var{bitrate}
304 Set min video bitrate (in bit/s).
305 Most useful in setting up a CBR encode:
307 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
309 It is of little use elsewise.
310 @item -bufsize @var{size}
311 Set video buffer verifier buffer size (in bits).
312 @item -vcodec @var{codec}
313 Set the video codec. This is an alias for @code{-codec:v}.
315 Use same quantizer as source (implies VBR).
317 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
321 Select the pass number (1 or 2). It is used to do two-pass
322 video encoding. The statistics of the video are recorded in the first
323 pass into a log file (see also the option -passlogfile),
324 and in the second pass that log file is used to generate the video
325 at the exact requested bitrate.
326 On pass 1, you may just deactivate audio and set output to null,
327 examples for Windows and Unix:
329 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
330 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
333 @item -passlogfile @var{prefix}
334 Set two-pass log file name prefix to @var{prefix}, the default file name
335 prefix is ``av2pass''. The complete file name will be
336 @file{PREFIX-N.log}, where N is a number specific to the output
339 @item -vlang @var{code}
340 Set the ISO 639 language code (3 letters) of the current video stream.
342 @item -vf @var{filter_graph}
343 @var{filter_graph} is a description of the filter graph to apply to
345 Use the option "-filters" to show all the available filters (including
346 also sources and sinks).
350 @section Advanced Video Options
353 @item -pix_fmt @var{format}
354 Set pixel format. Use 'list' as parameter to show all the supported
356 @item -sws_flags @var{flags}
358 @item -g @var{gop_size}
359 Set the group of pictures size.
362 @item -qscale @var{q}
363 Use fixed video quantizer scale (VBR).
365 minimum video quantizer scale (VBR)
367 maximum video quantizer scale (VBR)
369 maximum difference between the quantizer scales (VBR)
370 @item -qblur @var{blur}
371 video quantizer scale blur (VBR) (range 0.0 - 1.0)
372 @item -qcomp @var{compression}
373 video quantizer scale compression (VBR) (default 0.5).
374 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
376 @item -lmin @var{lambda}
377 minimum video lagrange factor (VBR)
378 @item -lmax @var{lambda}
379 max video lagrange factor (VBR)
380 @item -mblmin @var{lambda}
381 minimum macroblock quantizer scale (VBR)
382 @item -mblmax @var{lambda}
383 maximum macroblock quantizer scale (VBR)
385 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
386 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
388 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
391 @item -rc_init_cplx @var{complexity}
392 initial complexity for single pass encoding
393 @item -b_qfactor @var{factor}
394 qp factor between P- and B-frames
395 @item -i_qfactor @var{factor}
396 qp factor between P- and I-frames
397 @item -b_qoffset @var{offset}
398 qp offset between P- and B-frames
399 @item -i_qoffset @var{offset}
400 qp offset between P- and I-frames
401 @item -rc_eq @var{equation}
402 Set rate control equation (see section "Expression Evaluation")
403 (default = @code{tex^qComp}).
405 When computing the rate control equation expression, besides the
406 standard functions defined in the section "Expression Evaluation", the
407 following functions are available:
413 and the following constants are available:
435 @item -rc_override @var{override}
436 rate control override for specific intervals
437 @item -me_method @var{method}
438 Set motion estimation method to @var{method}.
439 Available methods are (from lowest to best quality):
442 Try just the (0, 0) vector.
451 exhaustive search (slow and marginally better than epzs)
454 @item -dct_algo @var{algo}
455 Set DCT algorithm to @var{algo}. Available values are:
458 FF_DCT_AUTO (default)
471 @item -idct_algo @var{algo}
472 Set IDCT algorithm to @var{algo}. Available values are:
475 FF_IDCT_AUTO (default)
499 Set error resilience to @var{n}.
502 FF_ER_CAREFUL (default)
508 FF_ER_VERY_AGGRESSIVE
511 @item -ec @var{bit_mask}
512 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
513 the following values:
516 FF_EC_GUESS_MVS (default = enabled)
518 FF_EC_DEBLOCK (default = enabled)
521 @item -bf @var{frames}
522 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
523 @item -mbd @var{mode}
527 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
529 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
531 FF_MB_DECISION_RD: rate distortion
535 Use four motion vector by macroblock (MPEG-4 only).
537 Use data partitioning (MPEG-4 only).
538 @item -bug @var{param}
539 Work around encoder bugs that are not auto-detected.
540 @item -strict @var{strictness}
541 How strictly to follow the standards.
543 Enable Advanced intra coding (h263+).
545 Enable Unlimited Motion Vector (h263+)
548 Deinterlace pictures.
550 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
551 Use this option if your input file is interlaced and you want
552 to keep the interlaced format for minimum losses.
553 The alternative is to deinterlace the input stream with
554 @option{-deinterlace}, but deinterlacing introduces losses.
556 Calculate PSNR of compressed frames.
558 Dump video coding statistics to @file{vstats_HHMMSS.log}.
559 @item -vstats_file @var{file}
560 Dump video coding statistics to @var{file}.
562 top=1/bottom=0/auto=-1 field first
563 @item -dc @var{precision}
565 @item -vtag @var{fourcc/tag}
566 Force video tag/fourcc.
569 @item -vbsf @var{bitstream_filter}
570 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump", "mjpeg2jpeg".
572 avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
574 @item -force_key_frames @var{time}[,@var{time}...]
575 Force key frames at the specified timestamps, more precisely at the first
576 frames after each specified time.
577 This option can be useful to ensure that a seek point is present at a
578 chapter mark or any other designated place in the output file.
579 The timestamps must be specified in ascending order.
582 @section Audio Options
585 @item -aframes @var{number}
586 Set the number of audio frames to record.
588 Set the audio sampling frequency. For output streams it is set by
589 default to the frequency of the corresponding input stream. For input
590 streams this option only makes sense for audio grabbing devices and raw
591 demuxers and is mapped to the corresponding demuxer options.
593 Set the audio quality (codec-specific, VBR).
594 @item -ac @var{channels}
595 Set the number of audio channels. For output streams it is set by
596 default to the number of input audio channels. For input streams
597 this option only makes sense for audio grabbing devices and raw demuxers
598 and is mapped to the corresponding demuxer options.
600 Disable audio recording.
601 @item -acodec @var{codec}
602 Set the audio codec. This is an alias for @code{-codec:a}.
603 @item -alang @var{code}
604 Set the ISO 639 language code (3 letters) of the current audio stream.
607 @section Advanced Audio options:
610 @item -atag @var{fourcc/tag}
611 Force audio tag/fourcc.
612 @item -audio_service_type @var{type}
613 Set the type of service that the audio stream contains.
616 Main Audio Service (default)
634 @item -absf @var{bitstream_filter}
635 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
638 @section Subtitle options:
641 @item -scodec @var{codec}
642 Set the subtitle codec. This is an alias for @code{-codec:s}.
643 @item -slang @var{code}
644 Set the ISO 639 language code (3 letters) of the current subtitle stream.
646 Disable subtitle recording.
647 @item -sbsf @var{bitstream_filter}
648 Bitstream filters available are "mov2textsub", "text2movsub".
650 avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
654 @section Audio/Video grab options
658 Synchronize read on input.
661 @section Advanced options
664 @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}]]
666 Designate one or more input streams as a source for the output file. Each input
667 stream is identified by the input file index @var{input_file_id} and
668 the input stream index @var{input_stream_id} within the input
669 file. Both indices start at 0. If specified,
670 @var{sync_file_id}:@var{sync_stream_id} sets which input stream
671 is used as a presentation sync reference.
673 If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for
674 subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams
675 of this type. Same for @var{sync_stream_type}.
677 @var{input_stream_id} may be omitted, in which case all streams of the given
678 type are mapped (or all streams in the file, if no type is specified).
680 The first @code{-map} option on the command line specifies the
681 source for output stream 0, the second @code{-map} option specifies
682 the source for output stream 1, etc.
684 A @code{-} character before the stream identifier creates a "negative" mapping.
685 It disables matching streams from already created mappings.
687 For example, to map ALL streams from the first input file to output
689 avconv -i INPUT -map 0 output
692 For example, if you have two audio streams in the first input file,
693 these streams are identified by "0:0" and "0:1". You can use
694 @code{-map} to select which streams to place in an output file. For
697 avconv -i INPUT -map 0:1 out.wav
699 will map the input stream in @file{INPUT} identified by "0:1" to
700 the (single) output stream in @file{out.wav}.
702 For example, to select the stream with index 2 from input file
703 @file{a.mov} (specified by the identifier "0:2"), and stream with
704 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
705 and copy them to the output file @file{out.mov}:
707 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
710 To select all video and the third audio stream from an input file:
712 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
715 To map all the streams except the second audio, use negative mappings
717 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
720 Note that using this option disables the default mappings for this output file.
722 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}]
723 Set metadata information of the next output file from @var{infile}. Note that
724 those are file indices (zero-based), not filenames.
725 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
726 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
727 per-(p)rogram. All metadata specifiers other than global must be followed by the
728 stream/chapter/program index. If metadata specifier is omitted, it defaults to
731 By default, global metadata is copied from the first input file,
732 per-stream and per-chapter metadata is copied along with streams/chapters. These
733 default mappings are disabled by creating any mapping of the relevant type. A negative
734 file index can be used to create a dummy mapping that just disables automatic copying.
736 For example to copy metadata from the first stream of the input file to global metadata
739 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
741 @item -map_chapters @var{input_file_index}
742 Copy chapters from input file with index @var{input_file_index} to the next
743 output file. If no chapter mapping is specified, then chapters are copied from
744 the first input file with at least one chapter. Use a negative file index to
745 disable any chapter copying.
747 Print specific debug info.
749 Show benchmarking information at the end of an encode.
750 Shows CPU time used and maximum memory consumption.
751 Maximum memory consumption is not supported on all systems,
752 it will usually display as 0 if not supported.
754 Dump each input packet.
756 When dumping packets, also dump the payload.
758 Only use bit exact algorithms (for codec testing).
760 Set RTP payload size in bytes.
762 Read input at native frame rate. Mainly used to simulate a grab device.
763 @item -threads @var{count}
765 @item -vsync @var{parameter}
770 Each frame is passed with its timestamp from the demuxer to the muxer.
772 Frames will be duplicated and dropped to achieve exactly the requested
775 Frames are passed through with their timestamp or dropped so as to
776 prevent 2 frames from having the same timestamp.
778 Chooses between 1 and 2 depending on muxer capabilities. This is the
782 With -map you can select from which stream the timestamps should be
783 taken. You can leave either video or audio unchanged and sync the
784 remaining stream(s) to the unchanged one.
786 @item -async @var{samples_per_second}
787 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
788 the parameter is the maximum samples per second by which the audio is changed.
789 -async 1 is a special case where only the start of the audio stream is corrected
790 without any later correction.
792 Copy timestamps from input to output.
794 Copy input stream time base from input to output when stream copying.
796 Finish encoding when the shortest input stream ends.
797 @item -dts_delta_threshold
798 Timestamp discontinuity delta threshold.
799 @item -muxdelay @var{seconds}
800 Set the maximum demux-decode delay.
801 @item -muxpreload @var{seconds}
802 Set the initial demux-decode delay.
803 @item -streamid @var{output-stream-index}:@var{new-value}
804 Assign a new stream-id value to an output stream. This option should be
805 specified prior to the output filename to which it applies.
806 For the situation where multiple output files exist, a streamid
807 may be reassigned to a different value.
809 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
810 an output mpegts file:
812 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
822 For streaming at very low bitrate application, use a low frame rate
823 and a small GOP size. This is especially true for RealVideo where
824 the Linux player does not seem to be very fast, so it can miss
825 frames. An example is:
828 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
832 The parameter 'q' which is displayed while encoding is the current
833 quantizer. The value 1 indicates that a very good quality could
834 be achieved. The value 31 indicates the worst quality. If q=31 appears
835 too often, it means that the encoder cannot compress enough to meet
836 your bitrate. You must either increase the bitrate, decrease the
837 frame rate or decrease the frame size.
840 If your computer is not fast enough, you can speed up the
841 compression at the expense of the compression ratio. You can use
842 '-me zero' to speed up motion estimation, and '-intra' to disable
843 motion estimation completely (you have only I-frames, which means it
844 is about as good as JPEG compression).
847 To have very low audio bitrates, reduce the sampling frequency
848 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
851 To have a constant quality (but a variable bitrate), use the option
852 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
859 @c man begin EXAMPLES
861 @section Video and Audio grabbing
863 If you specify the input format and device then avconv can grab video
867 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
870 Note that you must activate the right video source and channel before
871 launching avconv with any TV viewer such as
872 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
873 have to set the audio recording levels correctly with a
876 @section X11 grabbing
878 Grab the X11 display with avconv via
881 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
884 0.0 is display.screen number of your X11 server, same as
885 the DISPLAY environment variable.
888 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
891 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
892 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
894 @section Video and Audio file format conversion
896 Any supported file format and protocol can serve as input to avconv:
901 You can use YUV files as input:
904 avconv -i /tmp/test%d.Y /tmp/out.mpg
907 It will use the files:
909 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
910 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
913 The Y files use twice the resolution of the U and V files. They are
914 raw files, without header. They can be generated by all decent video
915 decoders. You must specify the size of the image with the @option{-s} option
916 if avconv cannot guess it.
919 You can input from a raw YUV420P file:
922 avconv -i /tmp/test.yuv /tmp/out.avi
925 test.yuv is a file containing raw YUV planar data. Each frame is composed
926 of the Y plane followed by the U and V planes at half vertical and
927 horizontal resolution.
930 You can output to a raw YUV420P file:
933 avconv -i mydivx.avi hugefile.yuv
937 You can set several input files and output files:
940 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
943 Converts the audio file a.wav and the raw YUV video file a.yuv
947 You can also do audio and video conversions at the same time:
950 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
953 Converts a.wav to MPEG audio at 22050 Hz sample rate.
956 You can encode to several formats at the same time and define a
957 mapping from input stream to output streams:
960 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
963 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
964 file:index' specifies which input stream is used for each output
965 stream, in the order of the definition of output streams.
968 You can transcode decrypted VOBs:
971 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
974 This is a typical DVD ripping example; the input is a VOB file, the
975 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
976 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
977 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
978 input video. Furthermore, the audio stream is MP3-encoded so you need
979 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
980 The mapping is particularly useful for DVD transcoding
981 to get the desired audio language.
983 NOTE: To see the supported input formats, use @code{avconv -formats}.
986 You can extract images from a video, or create a video from many images:
988 For extracting images from a video:
990 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
993 This will extract one video frame per second from the video and will
994 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
995 etc. Images will be rescaled to fit the new WxH values.
997 If you want to extract just a limited number of frames, you can use the
998 above command in combination with the -vframes or -t option, or in
999 combination with -ss to start extracting from a certain point in time.
1001 For creating a video from many images:
1003 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1006 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1007 composed of three digits padded with zeroes to express the sequence
1008 number. It is the same syntax supported by the C printf function, but
1009 only formats accepting a normal integer are suitable.
1012 You can put many streams of the same type in the output:
1015 avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1018 The resulting output file @file{test12.avi} will contain first four streams from
1019 the input file in reverse order.
1025 @include encoders.texi
1026 @include demuxers.texi
1027 @include muxers.texi
1028 @include indevs.texi
1029 @include outdevs.texi
1030 @include protocols.texi
1031 @include bitstream_filters.texi
1032 @include filters.texi
1033 @include metadata.texi
1038 @settitle avconv video converter
1040 @c man begin SEEALSO
1041 avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation
1044 @c man begin AUTHORS
1045 The Libav developers