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 Detailed description
83 @c man begin DETAILED DESCRIPTION
85 The transcoding process in @command{avconv} for each output can be described by
86 the following diagram:
89 _______ ______________
91 | input | demuxer | encoded data | decoder
92 | file | ---------> | packets | -----+
93 |_______| |______________| |
100 ________ ______________ |
102 | output | <-------- | encoded data | <----+
103 | file | muxer | packets | encoder
104 |________| |______________|
109 @command{avconv} calls the libavformat library (containing demuxers) to read
110 input files and get packets containing encoded data from them. When there are
111 multiple input files, @command{avconv} tries to keep them synchronized by
112 tracking lowest timestamp on any active input stream.
114 Encoded packets are then passed to the decoder (unless streamcopy is selected
115 for the stream, see further for a description). The decoder produces
116 uncompressed frames (raw video/PCM audio/...) which can be processed further by
117 filtering (see next section). After filtering the frames are passed to the
118 encoder, which encodes them and outputs encoded packets again. Finally those are
119 passed to the muxer, which writes the encoded packets to the output file.
122 Before encoding, @command{avconv} can process raw audio and video frames using
123 filters from the libavfilter library. Several chained filters form a filter
124 graph. @command{avconv} distinguishes between two types of filtergraphs -
127 @subsection Simple filtergraphs
128 Simple filtergraphs are those that have exactly one input and output, both of
129 the same type. In the above diagram they can be represented by simply inserting
130 an additional step between decoding and encoding:
133 _________ ______________
135 | decoded | | encoded data |
136 | frames |\ /| packets |
137 |_________| \ / |______________|
139 simple \ | | / encoder
140 filtergraph \| filtered |/
146 Simple filtergraphs are configured with the per-stream @option{-filter} option
147 (with @option{-vf} and @option{-af} aliases for video and audio respectively).
148 A simple filtergraph for video can look for example like this:
151 _______ _____________ _______ ________
153 | input | ---> | deinterlace | ---> | scale | ---> | output |
154 |_______| |_____________| |_______| |________|
158 Note that some filters change frame properties but not frame contents. E.g. the
159 @code{fps} filter in the example above changes number of frames, but does not
160 touch the frame contents. Another example is the @code{setpts} filter, which
161 only sets timestamps and otherwise passes the frames unchanged.
163 @subsection Complex filtergraphs
164 Complex filtergraphs are those which cannot be described as simply a linear
165 processing chain applied to one stream. This is the case e.g. when the graph has
166 more than one input and/or output, or when output stream type is different from
167 input. They can be represented with the following diagram:
172 | input 0 |\ __________
174 \ _________ /| output 0 |
176 _________ \| complex | /
178 | input 1 |---->| filter |\
179 |_________| | | \ __________
182 _________ / |_________| |__________|
189 Complex filtergraphs are configured with the @option{-filter_complex} option.
190 Note that this option is global, since a complex filtergraph by its nature
191 cannot be unambiguously associated with a single stream or file.
193 A trivial example of a complex filtergraph is the @code{overlay} filter, which
194 has two video inputs and one video output, containing one video overlaid on top
195 of the other. Its audio counterpart is the @code{amix} filter.
198 Stream copy is a mode selected by supplying the @code{copy} parameter to the
199 @option{-codec} option. It makes @command{avconv} omit the decoding and encoding
200 step for the specified stream, so it does only demuxing and muxing. It is useful
201 for changing the container format or modifying container-level metadata. The
202 diagram above will in this case simplify to this:
205 _______ ______________ ________
207 | input | demuxer | encoded data | muxer | output |
208 | file | ---------> | packets | -------> | file |
209 |_______| |______________| |________|
213 Since there is no decoding or encoding, it is very fast and there is no quality
214 loss. However it might not work in some cases because of many factors. Applying
215 filters is obviously also impossible, since filters work on uncompressed data.
217 @c man end DETAILED DESCRIPTION
219 @chapter Stream selection
220 @c man begin STREAM SELECTION
222 By default avconv tries to pick the "best" stream of each type present in input
223 files and add them to each output file. For video, this means the highest
224 resolution, for audio the highest channel count. For subtitle it's simply the
225 first subtitle stream.
227 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
228 full manual control, use the @code{-map} option, which disables the defaults just
231 @c man end STREAM SELECTION
236 @include avtools-common-opts.texi
238 @section Main options
242 @item -f @var{fmt} (@emph{input/output})
243 Force input or output file format. The format is normally autodetected for input
244 files and guessed from file extension for output files, so this option is not
245 needed in most cases.
247 @item -i @var{filename} (@emph{input})
250 @item -y (@emph{global})
251 Overwrite output files without asking.
253 @item -n (@emph{global})
254 Immediately exit when output files already exist.
256 @item -loop @var{number} (@emph{input})
257 Set number of times input stream shall be looped. Loop 0 means no loop,
258 loop -1 means infinite loop.
260 @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
261 @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
262 Select an encoder (when used before an output file) or a decoder (when used
263 before an input file) for one or more streams. @var{codec} is the name of a
264 decoder/encoder or a special value @code{copy} (output only) to indicate that
265 the stream is not to be reencoded.
269 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
271 encodes all video streams with libx264 and copies all audio streams.
273 For each stream, the last matching @code{c} option is applied, so
275 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
277 will copy all the streams except the second video, which will be encoded with
278 libx264, and the 138th audio, which will be encoded with libvorbis.
280 @item -t @var{duration} (@emph{output})
281 Stop writing the output after its duration reaches @var{duration}.
282 @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
284 @item -fs @var{limit_size} (@emph{output})
285 Set the file size limit.
287 @item -ss @var{position} (@emph{input/output})
288 When used as an input option (before @code{-i}), seeks in this input file to
289 @var{position}. Note the in most formats it is not possible to seek exactly, so
290 @command{avconv} will seek to the closest seek point before @var{position}.
291 When transcoding and @option{-accurate_seek} is enabled (the default), this
292 extra segment between the seek point and @var{position} will be decoded and
293 discarded. When doing stream copy or when @option{-noaccurate_seek} is used, it
296 When used as an output option (before an output filename), decodes but discards
297 input until the timestamps reach @var{position}.
299 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
301 @item -itsoffset @var{offset} (@emph{input})
302 Set the input time offset in seconds.
303 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
304 The offset is added to the timestamps of the input files.
305 Specifying a positive offset means that the corresponding
306 streams are delayed by @var{offset} seconds.
308 @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
309 Set a metadata key/value pair.
311 An optional @var{metadata_specifier} may be given to set metadata
312 on streams or chapters. See @code{-map_metadata} documentation for
315 This option overrides metadata set with @code{-map_metadata}. It is
316 also possible to delete metadata by using an empty value.
318 For example, for setting the title in the output file:
320 avconv -i in.avi -metadata title="my title" out.flv
323 To set the language of the first audio stream:
325 avconv -i INPUT -metadata:s:a:0 language=eng OUTPUT
328 @item -target @var{type} (@emph{output})
329 Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
330 @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
331 @code{film-} to use the corresponding standard. All the format options
332 (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
335 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
338 Nevertheless you can specify additional options as long as you know
339 they do not conflict with the standard, as in:
342 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
345 @item -dframes @var{number} (@emph{output})
346 Set the number of data frames to record. This is an obsolete alias for
347 @code{-frames:d}, which you should use instead.
349 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
350 Stop writing to the stream after @var{framecount} frames.
352 @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
353 @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
354 Use fixed quality scale (VBR). The meaning of @var{q} is
357 @item -b[:@var{stream_specifier}] @var{bitrate} (@emph{output,per-stream})
358 Set the stream bitrate in bits per second. When transcoding, this tells the
359 encoder to use the specified bitrate for the encoded stream.
361 For streamcopy, this provides a hint to the muxer about the bitrate of the input
364 @item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
365 @var{filter_graph} is a description of the filter graph to apply to
366 the stream. Use @code{-filters} to show all the available filters
367 (including also sources and sinks).
369 See also the @option{-filter_complex} option if you want to create filter graphs
370 with multiple inputs and/or outputs.
372 @item -filter_script[:@var{stream_specifier}] @var{filename} (@emph{output,per-stream})
373 This option is similar to @option{-filter}, the only difference is that its
374 argument is the name of the file from which a filtergraph description is to be
377 @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
378 Specify the preset for matching stream(s).
380 @item -stats (@emph{global})
381 Print encoding progress/statistics. On by default.
383 @item -attach @var{filename} (@emph{output})
384 Add an attachment to the output file. This is supported by a few formats
385 like Matroska for e.g. fonts used in rendering subtitles. Attachments
386 are implemented as a specific type of stream, so this option will add
387 a new stream to the file. It is then possible to use per-stream options
388 on this stream in the usual way. Attachment streams created with this
389 option will be created after all the other streams (i.e. those created
390 with @code{-map} or automatic mappings).
392 Note that for Matroska you also have to set the mimetype metadata tag:
394 avconv -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
396 (assuming that the attachment stream will be third in the output file).
398 @item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
399 Extract the matching attachment stream into a file named @var{filename}. If
400 @var{filename} is empty, then the value of the @code{filename} metadata tag
403 E.g. to extract the first attachment to a file named 'out.ttf':
405 avconv -dump_attachment:t:0 out.ttf INPUT
407 To extract all attachments to files determined by the @code{filename} tag:
409 avconv -dump_attachment:t "" INPUT
412 Technical note -- attachments are implemented as codec extradata, so this
413 option can actually be used to extract extradata from any stream, not just
417 Disable automatically rotating video based on file metadata.
421 @section Video Options
424 @item -vframes @var{number} (@emph{output})
425 Set the number of video frames to record. This is an obsolete alias for
426 @code{-frames:v}, which you should use instead.
427 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
428 Set frame rate (Hz value, fraction or abbreviation).
430 As an input option, ignore any timestamps stored in the file and instead
431 generate timestamps assuming constant frame rate @var{fps}.
433 As an output option, duplicate or drop input frames to achieve constant output
434 frame rate @var{fps} (note that this actually causes the @code{fps} filter to be
435 inserted to the end of the corresponding filtergraph).
437 @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
440 As an input option, this is a shortcut for the @option{video_size} private
441 option, recognized by some demuxers for which the frame size is either not
442 stored in the file or is configurable -- e.g. raw video or video grabbers.
444 As an output option, this inserts the @code{scale} video filter to the
445 @emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
446 directly to insert it at the beginning or some other place.
448 The format is @samp{wxh} (default - same as source). The following
449 abbreviations are recognized:
519 @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
520 Set the video display aspect ratio specified by @var{aspect}.
522 @var{aspect} can be a floating point number string, or a string of the
523 form @var{num}:@var{den}, where @var{num} and @var{den} are the
524 numerator and denominator of the aspect ratio. For example "4:3",
525 "16:9", "1.3333", and "1.7777" are valid argument values.
527 @item -vn (@emph{output})
528 Disable video recording.
530 @item -vcodec @var{codec} (@emph{output})
531 Set the video codec. This is an alias for @code{-codec:v}.
533 @item -pass[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
534 Select the pass number (1 or 2). It is used to do two-pass
535 video encoding. The statistics of the video are recorded in the first
536 pass into a log file (see also the option -passlogfile),
537 and in the second pass that log file is used to generate the video
538 at the exact requested bitrate.
539 On pass 1, you may just deactivate audio and set output to null,
540 examples for Windows and Unix:
542 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
543 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
546 @item -passlogfile[:@var{stream_specifier}] @var{prefix} (@emph{output,per-stream})
547 Set two-pass log file name prefix to @var{prefix}, the default file name
548 prefix is ``av2pass''. The complete file name will be
549 @file{PREFIX-N.log}, where N is a number specific to the output
552 @item -vf @var{filter_graph} (@emph{output})
553 @var{filter_graph} is a description of the filter graph to apply to
555 Use the option "-filters" to show all the available filters (including
556 also sources and sinks). This is an alias for @code{-filter:v}.
560 @section Advanced Video Options
563 @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
564 Set pixel format. Use @code{-pix_fmts} to show all the supported
566 @item -sws_flags @var{flags} (@emph{input/output})
571 @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
572 rate control override for specific intervals
575 Dump video coding statistics to @file{vstats_HHMMSS.log}.
576 @item -vstats_file @var{file}
577 Dump video coding statistics to @var{file}.
578 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
579 top=1/bottom=0/auto=-1 field first
580 @item -dc @var{precision}
582 @item -vtag @var{fourcc/tag} (@emph{output})
583 Force video tag/fourcc. This is an alias for @code{-tag:v}.
584 @item -qphist (@emph{global})
586 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
587 Force key frames at the specified timestamps, more precisely at the first
588 frames after each specified time.
589 This option can be useful to ensure that a seek point is present at a
590 chapter mark or any other designated place in the output file.
591 The timestamps must be specified in ascending order.
593 @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
594 When doing stream copy, copy also non-key frames found at the
597 @item -init_hw_device @var{type}[=@var{name}][:@var{device}[,@var{key=value}...]]
598 Initialise a new hardware device of type @var{type} called @var{name}, using the
599 given device parameters.
600 If no name is specified it will receive a default name of the form "@var{type}%d".
602 The meaning of @var{device} and the following arguments depends on the
607 @var{device} is the number of the CUDA device.
610 @var{device} is the number of the Direct3D 9 display adapter.
613 @var{device} is either an X11 display name or a DRM render node.
614 If not specified, it will attempt to open the default X11 display (@emph{$DISPLAY})
615 and then the first DRM render node (@emph{/dev/dri/renderD128}).
618 @var{device} is an X11 display name.
619 If not specified, it will attempt to open the default X11 display (@emph{$DISPLAY}).
622 @var{device} selects a value in @samp{MFX_IMPL_*}. Allowed values are:
633 If not specified, @samp{auto_any} is used.
634 (Note that it may be easier to achieve the desired result for QSV by creating the
635 platform-appropriate subdevice (@samp{dxva2} or @samp{vaapi}) and then deriving a
636 QSV device from that.)
640 @item -init_hw_device @var{type}[=@var{name}]@@@var{source}
641 Initialise a new hardware device of type @var{type} called @var{name},
642 deriving it from the existing device with the name @var{source}.
644 @item -init_hw_device list
645 List all hardware device types supported in this build of avconv.
647 @item -hwaccel[:@var{stream_specifier}] @var{hwaccel} (@emph{input,per-stream})
648 Use hardware acceleration to decode the matching stream(s). The allowed values
649 of @var{hwaccel} are:
652 Do not use any hardware acceleration (the default).
655 Automatically select the hardware acceleration method.
658 Use Apple VDA hardware acceleration.
661 Use VDPAU (Video Decode and Presentation API for Unix) hardware acceleration.
664 Use DXVA2 (DirectX Video Acceleration) hardware acceleration.
667 Use VAAPI (Video Acceleration API) hardware acceleration.
670 Use the Intel QuickSync Video acceleration for video transcoding.
672 Unlike most other values, this option does not enable accelerated decoding (that
673 is used automatically whenever a qsv decoder is selected), but accelerated
674 transcoding, without copying the frames into the system memory.
676 For it to work, both the decoder and the encoder must support QSV acceleration
677 and no filters must be used.
680 This option has no effect if the selected hwaccel is not available or not
681 supported by the chosen decoder.
683 Note that most acceleration methods are intended for playback and will not be
684 faster than software decoding on modern CPUs. Additionally, @command{avconv}
685 will usually need to copy the decoded frames from the GPU memory into the system
686 memory, resulting in further performance loss. This option is thus mainly
689 @item -hwaccel_device[:@var{stream_specifier}] @var{hwaccel_device} (@emph{input,per-stream})
690 Select a device to use for hardware acceleration.
692 This option only makes sense when the @option{-hwaccel} option is also specified.
693 It can either refer to an existing device created with @option{-init_hw_device}
694 by name, or it can create a new device as if
695 @samp{-init_hw_device} @var{type}:@var{hwaccel_device}
696 were called immediately before.
699 List all hardware acceleration methods supported in this build of avconv.
703 @section Audio Options
706 @item -aframes @var{number} (@emph{output})
707 Set the number of audio frames to record. This is an obsolete alias for
708 @code{-frames:a}, which you should use instead.
709 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
710 Set the audio sampling frequency. For output streams it is set by
711 default to the frequency of the corresponding input stream. For input
712 streams this option only makes sense for audio grabbing devices and raw
713 demuxers and is mapped to the corresponding demuxer options.
714 @item -aq @var{q} (@emph{output})
715 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
716 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
717 Set the number of audio channels. For output streams it is set by
718 default to the number of input audio channels. For input streams
719 this option only makes sense for audio grabbing devices and raw demuxers
720 and is mapped to the corresponding demuxer options.
721 @item -an (@emph{output})
722 Disable audio recording.
723 @item -acodec @var{codec} (@emph{input/output})
724 Set the audio codec. This is an alias for @code{-codec:a}.
725 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
726 Set the audio sample format. Use @code{-sample_fmts} to get a list
727 of supported sample formats.
728 @item -af @var{filter_graph} (@emph{output})
729 @var{filter_graph} is a description of the filter graph to apply to
731 Use the option "-filters" to show all the available filters (including
732 also sources and sinks). This is an alias for @code{-filter:a}.
735 @section Advanced Audio options:
738 @item -atag @var{fourcc/tag} (@emph{output})
739 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
742 @section Subtitle options:
745 @item -scodec @var{codec} (@emph{input/output})
746 Set the subtitle codec. This is an alias for @code{-codec:s}.
747 @item -sn (@emph{output})
748 Disable subtitle recording.
751 @section Advanced options
754 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
756 Designate one or more input streams as a source for the output file. Each input
757 stream is identified by the input file index @var{input_file_id} and
758 the input stream index @var{input_stream_id} within the input
759 file. Both indices start at 0. If specified,
760 @var{sync_file_id}:@var{stream_specifier} sets which input stream
761 is used as a presentation sync reference.
763 The first @code{-map} option on the command line specifies the
764 source for output stream 0, the second @code{-map} option specifies
765 the source for output stream 1, etc.
767 A @code{-} character before the stream identifier creates a "negative" mapping.
768 It disables matching streams from already created mappings.
770 An alternative @var{[linklabel]} form will map outputs from complex filter
771 graphs (see the @option{-filter_complex} option) to the output file.
772 @var{linklabel} must correspond to a defined output link label in the graph.
774 For example, to map ALL streams from the first input file to output
776 avconv -i INPUT -map 0 output
779 For example, if you have two audio streams in the first input file,
780 these streams are identified by "0:0" and "0:1". You can use
781 @code{-map} to select which streams to place in an output file. For
784 avconv -i INPUT -map 0:1 out.wav
786 will map the input stream in @file{INPUT} identified by "0:1" to
787 the (single) output stream in @file{out.wav}.
789 For example, to select the stream with index 2 from input file
790 @file{a.mov} (specified by the identifier "0:2"), and stream with
791 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
792 and copy them to the output file @file{out.mov}:
794 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
797 To select all video and the third audio stream from an input file:
799 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
802 To map all the streams except the second audio, use negative mappings
804 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
807 To pick the English audio stream:
809 avconv -i INPUT -map 0:m:language:eng OUTPUT
812 Note that using this option disables the default mappings for this output file.
814 @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
815 Set metadata information of the next output file from @var{infile}. Note that
816 those are file indices (zero-based), not filenames.
817 Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
818 A metadata specifier can have the following forms:
821 global metadata, i.e. metadata that applies to the whole file
823 @item @var{s}[:@var{stream_spec}]
824 per-stream metadata. @var{stream_spec} is a stream specifier as described
825 in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
826 matching stream is copied from. In an output metadata specifier, all matching
827 streams are copied to.
829 @item @var{c}:@var{chapter_index}
830 per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
832 @item @var{p}:@var{program_index}
833 per-program metadata. @var{program_index} is the zero-based program index.
835 If metadata specifier is omitted, it defaults to global.
837 By default, global metadata is copied from the first input file,
838 per-stream and per-chapter metadata is copied along with streams/chapters. These
839 default mappings are disabled by creating any mapping of the relevant type. A negative
840 file index can be used to create a dummy mapping that just disables automatic copying.
842 For example to copy metadata from the first stream of the input file to global metadata
845 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
848 To do the reverse, i.e. copy global metadata to all audio streams:
850 avconv -i in.mkv -map_metadata:s:a 0:g out.mkv
852 Note that simple @code{0} would work as well in this example, since global
853 metadata is assumed by default.
855 @item -map_chapters @var{input_file_index} (@emph{output})
856 Copy chapters from input file with index @var{input_file_index} to the next
857 output file. If no chapter mapping is specified, then chapters are copied from
858 the first input file with at least one chapter. Use a negative file index to
859 disable any chapter copying.
861 Print specific debug info.
862 @item -benchmark (@emph{global})
863 Show benchmarking information at the end of an encode.
864 Shows CPU time used and maximum memory consumption.
865 Maximum memory consumption is not supported on all systems,
866 it will usually display as 0 if not supported.
867 @item -timelimit @var{duration} (@emph{global})
868 Exit after avconv has been running for @var{duration} seconds.
869 @item -dump (@emph{global})
870 Dump each input packet to stderr.
871 @item -hex (@emph{global})
872 When dumping packets, also dump the payload.
873 @item -re (@emph{input})
874 Read input at native frame rate. Mainly used to simulate a grab device
875 or live input stream (e.g. when reading from a file). Should not be used
876 with actual grab devices or live input streams (where it can cause packet
878 @item -vsync @var{parameter}
883 Each frame is passed with its timestamp from the demuxer to the muxer.
885 Frames will be duplicated and dropped to achieve exactly the requested
888 Frames are passed through with their timestamp or dropped so as to
889 prevent 2 frames from having the same timestamp.
891 Chooses between 1 and 2 depending on muxer capabilities. This is the
895 With -map you can select from which stream the timestamps should be
896 taken. You can leave either video or audio unchanged and sync the
897 remaining stream(s) to the unchanged one.
899 @item -async @var{samples_per_second}
900 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
901 the parameter is the maximum samples per second by which the audio is changed.
902 -async 1 is a special case where only the start of the audio stream is corrected
903 without any later correction.
904 This option has been deprecated. Use the @code{asyncts} audio filter instead.
906 Copy timestamps from input to output.
908 Copy input stream time base from input to output when stream copying.
909 @item -shortest (@emph{output})
910 Finish encoding when the shortest input stream ends.
911 @item -dts_delta_threshold
912 Timestamp discontinuity delta threshold.
913 @item -muxdelay @var{seconds} (@emph{input})
914 Set the maximum demux-decode delay.
915 @item -muxpreload @var{seconds} (@emph{input})
916 Set the initial demux-decode delay.
917 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
918 Assign a new stream-id value to an output stream. This option should be
919 specified prior to the output filename to which it applies.
920 For the situation where multiple output files exist, a streamid
921 may be reassigned to a different value.
923 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
924 an output mpegts file:
926 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
929 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
930 Set bitstream filters for matching streams. @var{bitstream_filters} is
931 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
932 to get the list of bitstream filters.
934 avconv -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
937 avconv -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
940 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{input/output,per-stream})
941 Force a tag/fourcc for matching streams.
943 @item -filter_complex @var{filtergraph} (@emph{global})
944 Define a complex filter graph, i.e. one with arbitrary number of inputs and/or
945 outputs. For simple graphs -- those with one input and one output of the same
946 type -- see the @option{-filter} options. @var{filtergraph} is a description of
947 the filter graph, as described in @ref{Filtergraph syntax}.
949 Input link labels must refer to input streams using the
950 @code{[file_index:stream_specifier]} syntax (i.e. the same as @option{-map}
951 uses). If @var{stream_specifier} matches multiple streams, the first one will be
952 used. An unlabeled input will be connected to the first unused input stream of
955 Output link labels are referred to with @option{-map}. Unlabeled outputs are
956 added to the first output file.
958 Note that with this option it is possible to use only lavfi sources without
961 For example, to overlay an image over video
963 avconv -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
966 Here @code{[0:v]} refers to the first video stream in the first input file,
967 which is linked to the first (main) input of the overlay filter. Similarly the
968 first video stream in the second input is linked to the second (overlay) input
971 Assuming there is only one video stream in each input file, we can omit input
972 labels, so the above is equivalent to
974 avconv -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
978 Furthermore we can omit the output label and the single output from the filter
979 graph will be added to the output file automatically, so we can simply write
981 avconv -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
984 To generate 5 seconds of pure red video using lavfi @code{color} source:
986 avconv -filter_complex 'color=red' -t 5 out.mkv
989 @item -filter_complex_script @var{filename} (@emph{global})
990 This option is similar to @option{-filter_complex}, the only difference is that
991 its argument is the name of the file from which a complex filtergraph
992 description is to be read.
994 @item -accurate_seek (@emph{input})
995 This option enables or disables accurate seeking in input files with the
996 @option{-ss} option. It is enabled by default, so seeking is accurate when
997 transcoding. Use @option{-noaccurate_seek} to disable it, which may be useful
998 e.g. when copying some streams and transcoding the others.
1000 @item -max_muxing_queue_size @var{packets} (@emph{output,per-stream})
1001 When transcoding audio and/or video streams, avconv will not begin writing into
1002 the output until it has one packet for each such stream. While waiting for that
1003 to happen, packets for other streams are buffered. This option sets the size of
1004 this buffer, in packets, for the matching output stream.
1006 The default value of this option should be high enough for most uses, so only
1007 touch this option if you are sure that you need it.
1017 For streaming at very low bitrate application, use a low frame rate
1018 and a small GOP size. This is especially true for RealVideo where
1019 the Linux player does not seem to be very fast, so it can miss
1020 frames. An example is:
1023 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
1027 The parameter 'q' which is displayed while encoding is the current
1028 quantizer. The value 1 indicates that a very good quality could
1029 be achieved. The value 31 indicates the worst quality. If q=31 appears
1030 too often, it means that the encoder cannot compress enough to meet
1031 your bitrate. You must either increase the bitrate, decrease the
1032 frame rate or decrease the frame size.
1035 If your computer is not fast enough, you can speed up the
1036 compression at the expense of the compression ratio. You can use
1037 '-me zero' to speed up motion estimation, and '-g 0' to disable
1038 motion estimation completely (you have only I-frames, which means it
1039 is about as good as JPEG compression).
1042 To have very low audio bitrates, reduce the sampling frequency
1043 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
1046 To have a constant quality (but a variable bitrate), use the option
1047 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
1054 @c man begin EXAMPLES
1056 @section Preset files
1058 A preset file contains a sequence of @var{option=value} pairs, one for
1059 each line, specifying a sequence of options which can be specified also on
1060 the command line. Lines starting with the hash ('#') character are ignored and
1061 are used to provide comments. Empty lines are also ignored. Check the
1062 @file{presets} directory in the Libav source tree for examples.
1064 Preset files are specified with the @code{pre} option, this option takes a
1065 preset name as input. Avconv searches for a file named @var{preset_name}.avpreset in
1066 the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.avconv}, and in
1067 the data directory defined at configuration time (usually @file{$PREFIX/share/avconv})
1068 in that order. For example, if the argument is @code{libx264-max}, it will
1069 search for the file @file{libx264-max.avpreset}.
1071 @section Video and Audio grabbing
1073 If you specify the input format and device then avconv can grab video
1077 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
1080 Note that you must activate the right video source and channel before
1081 launching avconv with any TV viewer such as
1082 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
1083 have to set the audio recording levels correctly with a
1086 @section X11 grabbing
1088 Grab the X11 display with avconv via
1091 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
1094 0.0 is display.screen number of your X11 server, same as
1095 the DISPLAY environment variable.
1098 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
1101 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
1102 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
1104 @section Video and Audio file format conversion
1106 Any supported file format and protocol can serve as input to avconv:
1111 You can use YUV files as input:
1114 avconv -i /tmp/test%d.Y /tmp/out.mpg
1117 It will use the files:
1119 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
1120 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
1123 The Y files use twice the resolution of the U and V files. They are
1124 raw files, without header. They can be generated by all decent video
1125 decoders. You must specify the size of the image with the @option{-s} option
1126 if avconv cannot guess it.
1129 You can input from a raw YUV420P file:
1132 avconv -i /tmp/test.yuv /tmp/out.avi
1135 test.yuv is a file containing raw YUV planar data. Each frame is composed
1136 of the Y plane followed by the U and V planes at half vertical and
1137 horizontal resolution.
1140 You can output to a raw YUV420P file:
1143 avconv -i mydivx.avi hugefile.yuv
1147 You can set several input files and output files:
1150 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
1153 Converts the audio file a.wav and the raw YUV video file a.yuv
1157 You can also do audio and video conversions at the same time:
1160 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
1163 Converts a.wav to MPEG audio at 22050 Hz sample rate.
1166 You can encode to several formats at the same time and define a
1167 mapping from input stream to output streams:
1170 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
1173 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
1174 file:index' specifies which input stream is used for each output
1175 stream, in the order of the definition of output streams.
1178 You can transcode decrypted VOBs:
1181 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
1184 This is a typical DVD ripping example; the input is a VOB file, the
1185 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
1186 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
1187 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
1188 input video. Furthermore, the audio stream is MP3-encoded so you need
1189 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
1190 The mapping is particularly useful for DVD transcoding
1191 to get the desired audio language.
1193 NOTE: To see the supported input formats, use @code{avconv -formats}.
1196 You can extract images from a video, or create a video from many images:
1198 For extracting images from a video:
1200 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
1203 This will extract one video frame per second from the video and will
1204 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1205 etc. Images will be rescaled to fit the new WxH values.
1207 If you want to extract just a limited number of frames, you can use the
1208 above command in combination with the @code{-frames:v} or @code{-t} option,
1209 or in combination with -ss to start extracting from a certain point in time.
1211 For creating a video from many images:
1213 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1216 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1217 composed of three digits padded with zeroes to express the sequence
1218 number. It is the same syntax supported by the C printf function, but
1219 only formats accepting a normal integer are suitable.
1222 You can put many streams of the same type in the output:
1225 avconv -i test1.avi -i test2.avi -map 1:1 -map 1:0 -map 0:1 -map 0:0 -c copy -y test12.nut
1228 The resulting output file @file{test12.nut} will contain the first four streams
1229 from the input files in reverse order.
1232 To force CBR video output:
1234 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
1238 The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
1239 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
1241 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
1248 @include decoders.texi
1249 @include encoders.texi
1250 @include demuxers.texi
1251 @include muxers.texi
1252 @include indevs.texi
1253 @include outdevs.texi
1254 @include protocols.texi
1255 @include bitstream_filters.texi
1256 @include filters.texi
1257 @include metadata.texi
1262 @settitle avconv video converter
1264 @c man begin SEEALSO
1265 avplay(1), avprobe(1) and the Libav HTML documentation
1268 @c man begin AUTHORS
1269 The Libav developers