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.
259 @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
260 @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
261 Select an encoder (when used before an output file) or a decoder (when used
262 before an input file) for one or more streams. @var{codec} is the name of a
263 decoder/encoder or a special value @code{copy} (output only) to indicate that
264 the stream is not to be reencoded.
268 avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
270 encodes all video streams with libx264 and copies all audio streams.
272 For each stream, the last matching @code{c} option is applied, so
274 avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
276 will copy all the streams except the second video, which will be encoded with
277 libx264, and the 138th audio, which will be encoded with libvorbis.
279 @item -t @var{duration} (@emph{output})
280 Stop writing the output after its duration reaches @var{duration}.
281 @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
283 @item -fs @var{limit_size} (@emph{output})
284 Set the file size limit.
286 @item -ss @var{position} (@emph{input/output})
287 When used as an input option (before @code{-i}), seeks in this input file to
288 @var{position}. Note the in most formats it is not possible to seek exactly, so
289 @command{avconv} will seek to the closest seek point before @var{position}.
290 When transcoding and @option{-accurate_seek} is enabled (the default), this
291 extra segment between the seek point and @var{position} will be decoded and
292 discarded. When doing stream copy or when @option{-noaccurate_seek} is used, it
295 When used as an output option (before an output filename), decodes but discards
296 input until the timestamps reach @var{position}.
298 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
300 @item -itsoffset @var{offset} (@emph{input})
301 Set the input time offset in seconds.
302 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
303 The offset is added to the timestamps of the input files.
304 Specifying a positive offset means that the corresponding
305 streams are delayed by @var{offset} seconds.
307 @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
308 Set a metadata key/value pair.
310 An optional @var{metadata_specifier} may be given to set metadata
311 on streams or chapters. See @code{-map_metadata} documentation for
314 This option overrides metadata set with @code{-map_metadata}. It is
315 also possible to delete metadata by using an empty value.
317 For example, for setting the title in the output file:
319 avconv -i in.avi -metadata title="my title" out.flv
322 To set the language of the first audio stream:
324 avconv -i INPUT -metadata:s:a:0 language=eng OUTPUT
327 @item -target @var{type} (@emph{output})
328 Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
329 @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
330 @code{film-} to use the corresponding standard. All the format options
331 (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
334 avconv -i myfile.avi -target vcd /tmp/vcd.mpg
337 Nevertheless you can specify additional options as long as you know
338 they do not conflict with the standard, as in:
341 avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
344 @item -dframes @var{number} (@emph{output})
345 Set the number of data frames to record. This is an alias for @code{-frames:d}.
347 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
348 Stop writing to the stream after @var{framecount} frames.
350 @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
351 @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
352 Use fixed quality scale (VBR). The meaning of @var{q} is
355 @item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
356 @var{filter_graph} is a description of the filter graph to apply to
357 the stream. Use @code{-filters} to show all the available filters
358 (including also sources and sinks).
360 See also the @option{-filter_complex} option if you want to create filter graphs
361 with multiple inputs and/or outputs.
363 @item -filter_script[:@var{stream_specifier}] @var{filename} (@emph{output,per-stream})
364 This option is similar to @option{-filter}, the only difference is that its
365 argument is the name of the file from which a filtergraph description is to be
368 @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
369 Specify the preset for matching stream(s).
371 @item -stats (@emph{global})
372 Print encoding progress/statistics. On by default.
374 @item -attach @var{filename} (@emph{output})
375 Add an attachment to the output file. This is supported by a few formats
376 like Matroska for e.g. fonts used in rendering subtitles. Attachments
377 are implemented as a specific type of stream, so this option will add
378 a new stream to the file. It is then possible to use per-stream options
379 on this stream in the usual way. Attachment streams created with this
380 option will be created after all the other streams (i.e. those created
381 with @code{-map} or automatic mappings).
383 Note that for Matroska you also have to set the mimetype metadata tag:
385 avconv -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
387 (assuming that the attachment stream will be third in the output file).
389 @item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
390 Extract the matching attachment stream into a file named @var{filename}. If
391 @var{filename} is empty, then the value of the @code{filename} metadata tag
394 E.g. to extract the first attachment to a file named 'out.ttf':
396 avconv -dump_attachment:t:0 out.ttf INPUT
398 To extract all attachments to files determined by the @code{filename} tag:
400 avconv -dump_attachment:t "" INPUT
403 Technical note -- attachments are implemented as codec extradata, so this
404 option can actually be used to extract extradata from any stream, not just
408 Disable automatically rotating video based on file metadata.
412 @section Video Options
415 @item -vframes @var{number} (@emph{output})
416 Set the number of video frames to record. This is an alias for @code{-frames:v}.
417 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
418 Set frame rate (Hz value, fraction or abbreviation).
420 As an input option, ignore any timestamps stored in the file and instead
421 generate timestamps assuming constant frame rate @var{fps}.
423 As an output option, duplicate or drop input frames to achieve constant output
424 frame rate @var{fps} (note that this actually causes the @code{fps} filter to be
425 inserted to the end of the corresponding filtergraph).
427 @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
430 As an input option, this is a shortcut for the @option{video_size} private
431 option, recognized by some demuxers for which the frame size is either not
432 stored in the file or is configurable -- e.g. raw video or video grabbers.
434 As an output option, this inserts the @code{scale} video filter to the
435 @emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
436 directly to insert it at the beginning or some other place.
438 The format is @samp{wxh} (default - same as source). The following
439 abbreviations are recognized:
509 @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
510 Set the video display aspect ratio specified by @var{aspect}.
512 @var{aspect} can be a floating point number string, or a string of the
513 form @var{num}:@var{den}, where @var{num} and @var{den} are the
514 numerator and denominator of the aspect ratio. For example "4:3",
515 "16:9", "1.3333", and "1.7777" are valid argument values.
517 @item -vn (@emph{output})
518 Disable video recording.
520 @item -vcodec @var{codec} (@emph{output})
521 Set the video codec. This is an alias for @code{-codec:v}.
523 @item -pass[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
524 Select the pass number (1 or 2). It is used to do two-pass
525 video encoding. The statistics of the video are recorded in the first
526 pass into a log file (see also the option -passlogfile),
527 and in the second pass that log file is used to generate the video
528 at the exact requested bitrate.
529 On pass 1, you may just deactivate audio and set output to null,
530 examples for Windows and Unix:
532 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
533 avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
536 @item -passlogfile[:@var{stream_specifier}] @var{prefix} (@emph{output,per-stream})
537 Set two-pass log file name prefix to @var{prefix}, the default file name
538 prefix is ``av2pass''. The complete file name will be
539 @file{PREFIX-N.log}, where N is a number specific to the output
542 @item -vf @var{filter_graph} (@emph{output})
543 @var{filter_graph} is a description of the filter graph to apply to
545 Use the option "-filters" to show all the available filters (including
546 also sources and sinks). This is an alias for @code{-filter:v}.
550 @section Advanced Video Options
553 @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
554 Set pixel format. Use @code{-pix_fmts} to show all the supported
556 @item -sws_flags @var{flags} (@emph{input/output})
561 @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
562 rate control override for specific intervals
565 Dump video coding statistics to @file{vstats_HHMMSS.log}.
566 @item -vstats_file @var{file}
567 Dump video coding statistics to @var{file}.
568 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
569 top=1/bottom=0/auto=-1 field first
570 @item -dc @var{precision}
572 @item -vtag @var{fourcc/tag} (@emph{output})
573 Force video tag/fourcc. This is an alias for @code{-tag:v}.
574 @item -qphist (@emph{global})
576 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
577 Force key frames at the specified timestamps, more precisely at the first
578 frames after each specified time.
579 This option can be useful to ensure that a seek point is present at a
580 chapter mark or any other designated place in the output file.
581 The timestamps must be specified in ascending order.
583 @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
584 When doing stream copy, copy also non-key frames found at the
587 @item -hwaccel[:@var{stream_specifier}] @var{hwaccel} (@emph{input,per-stream})
588 Use hardware acceleration to decode the matching stream(s). The allowed values
589 of @var{hwaccel} are:
592 Do not use any hardware acceleration (the default).
595 Automatically select the hardware acceleration method.
598 Use Apple VDA hardware acceleration.
601 Use VDPAU (Video Decode and Presentation API for Unix) hardware acceleration.
604 Use DXVA2 (DirectX Video Acceleration) hardware acceleration.
607 This option has no effect if the selected hwaccel is not available or not
608 supported by the chosen decoder.
610 Note that most acceleration methods are intended for playback and will not be
611 faster than software decoding on modern CPUs. Additionally, @command{avconv}
612 will usually need to copy the decoded frames from the GPU memory into the system
613 memory, resulting in further performance loss. This option is thus mainly
616 @item -hwaccel_device[:@var{stream_specifier}] @var{hwaccel_device} (@emph{input,per-stream})
617 Select a device to use for hardware acceleration.
619 This option only makes sense when the @option{-hwaccel} option is also
620 specified. Its exact meaning depends on the specific hardware acceleration
625 For VDPAU, this option specifies the X11 display/screen to use. If this option
626 is not specified, the value of the @var{DISPLAY} environment variable is used
629 For DXVA2, this option should contain the number of the display adapter to use.
630 If this option is not specified, the default adapter is used.
634 List all hardware acceleration methods supported in this build of avconv.
638 @section Audio Options
641 @item -aframes @var{number} (@emph{output})
642 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
643 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
644 Set the audio sampling frequency. For output streams it is set by
645 default to the frequency of the corresponding input stream. For input
646 streams this option only makes sense for audio grabbing devices and raw
647 demuxers and is mapped to the corresponding demuxer options.
648 @item -aq @var{q} (@emph{output})
649 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
650 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
651 Set the number of audio channels. For output streams it is set by
652 default to the number of input audio channels. For input streams
653 this option only makes sense for audio grabbing devices and raw demuxers
654 and is mapped to the corresponding demuxer options.
655 @item -an (@emph{output})
656 Disable audio recording.
657 @item -acodec @var{codec} (@emph{input/output})
658 Set the audio codec. This is an alias for @code{-codec:a}.
659 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
660 Set the audio sample format. Use @code{-sample_fmts} to get a list
661 of supported sample formats.
662 @item -af @var{filter_graph} (@emph{output})
663 @var{filter_graph} is a description of the filter graph to apply to
665 Use the option "-filters" to show all the available filters (including
666 also sources and sinks). This is an alias for @code{-filter:a}.
669 @section Advanced Audio options:
672 @item -atag @var{fourcc/tag} (@emph{output})
673 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
676 @section Subtitle options:
679 @item -scodec @var{codec} (@emph{input/output})
680 Set the subtitle codec. This is an alias for @code{-codec:s}.
681 @item -sn (@emph{output})
682 Disable subtitle recording.
685 @section Advanced options
688 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
690 Designate one or more input streams as a source for the output file. Each input
691 stream is identified by the input file index @var{input_file_id} and
692 the input stream index @var{input_stream_id} within the input
693 file. Both indices start at 0. If specified,
694 @var{sync_file_id}:@var{stream_specifier} sets which input stream
695 is used as a presentation sync reference.
697 The first @code{-map} option on the command line specifies the
698 source for output stream 0, the second @code{-map} option specifies
699 the source for output stream 1, etc.
701 A @code{-} character before the stream identifier creates a "negative" mapping.
702 It disables matching streams from already created mappings.
704 An alternative @var{[linklabel]} form will map outputs from complex filter
705 graphs (see the @option{-filter_complex} option) to the output file.
706 @var{linklabel} must correspond to a defined output link label in the graph.
708 For example, to map ALL streams from the first input file to output
710 avconv -i INPUT -map 0 output
713 For example, if you have two audio streams in the first input file,
714 these streams are identified by "0:0" and "0:1". You can use
715 @code{-map} to select which streams to place in an output file. For
718 avconv -i INPUT -map 0:1 out.wav
720 will map the input stream in @file{INPUT} identified by "0:1" to
721 the (single) output stream in @file{out.wav}.
723 For example, to select the stream with index 2 from input file
724 @file{a.mov} (specified by the identifier "0:2"), and stream with
725 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
726 and copy them to the output file @file{out.mov}:
728 avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
731 To select all video and the third audio stream from an input file:
733 avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
736 To map all the streams except the second audio, use negative mappings
738 avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
741 To pick the English audio stream:
743 avconv -i INPUT -map 0:m:language:eng OUTPUT
746 Note that using this option disables the default mappings for this output file.
748 @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
749 Set metadata information of the next output file from @var{infile}. Note that
750 those are file indices (zero-based), not filenames.
751 Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
752 A metadata specifier can have the following forms:
755 global metadata, i.e. metadata that applies to the whole file
757 @item @var{s}[:@var{stream_spec}]
758 per-stream metadata. @var{stream_spec} is a stream specifier as described
759 in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
760 matching stream is copied from. In an output metadata specifier, all matching
761 streams are copied to.
763 @item @var{c}:@var{chapter_index}
764 per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
766 @item @var{p}:@var{program_index}
767 per-program metadata. @var{program_index} is the zero-based program index.
769 If metadata specifier is omitted, it defaults to global.
771 By default, global metadata is copied from the first input file,
772 per-stream and per-chapter metadata is copied along with streams/chapters. These
773 default mappings are disabled by creating any mapping of the relevant type. A negative
774 file index can be used to create a dummy mapping that just disables automatic copying.
776 For example to copy metadata from the first stream of the input file to global metadata
779 avconv -i in.ogg -map_metadata 0:s:0 out.mp3
782 To do the reverse, i.e. copy global metadata to all audio streams:
784 avconv -i in.mkv -map_metadata:s:a 0:g out.mkv
786 Note that simple @code{0} would work as well in this example, since global
787 metadata is assumed by default.
789 @item -map_chapters @var{input_file_index} (@emph{output})
790 Copy chapters from input file with index @var{input_file_index} to the next
791 output file. If no chapter mapping is specified, then chapters are copied from
792 the first input file with at least one chapter. Use a negative file index to
793 disable any chapter copying.
795 Print specific debug info.
796 @item -benchmark (@emph{global})
797 Show benchmarking information at the end of an encode.
798 Shows CPU time used and maximum memory consumption.
799 Maximum memory consumption is not supported on all systems,
800 it will usually display as 0 if not supported.
801 @item -timelimit @var{duration} (@emph{global})
802 Exit after avconv has been running for @var{duration} seconds.
803 @item -dump (@emph{global})
804 Dump each input packet to stderr.
805 @item -hex (@emph{global})
806 When dumping packets, also dump the payload.
807 @item -re (@emph{input})
808 Read input at native frame rate. Mainly used to simulate a grab device
809 or live input stream (e.g. when reading from a file). Should not be used
810 with actual grab devices or live input streams (where it can cause packet
812 @item -vsync @var{parameter}
817 Each frame is passed with its timestamp from the demuxer to the muxer.
819 Frames will be duplicated and dropped to achieve exactly the requested
822 Frames are passed through with their timestamp or dropped so as to
823 prevent 2 frames from having the same timestamp.
825 Chooses between 1 and 2 depending on muxer capabilities. This is the
829 With -map you can select from which stream the timestamps should be
830 taken. You can leave either video or audio unchanged and sync the
831 remaining stream(s) to the unchanged one.
833 @item -async @var{samples_per_second}
834 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
835 the parameter is the maximum samples per second by which the audio is changed.
836 -async 1 is a special case where only the start of the audio stream is corrected
837 without any later correction.
838 This option has been deprecated. Use the @code{asyncts} audio filter instead.
840 Copy timestamps from input to output.
842 Copy input stream time base from input to output when stream copying.
843 @item -shortest (@emph{output})
844 Finish encoding when the shortest input stream ends.
845 @item -dts_delta_threshold
846 Timestamp discontinuity delta threshold.
847 @item -muxdelay @var{seconds} (@emph{input})
848 Set the maximum demux-decode delay.
849 @item -muxpreload @var{seconds} (@emph{input})
850 Set the initial demux-decode delay.
851 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
852 Assign a new stream-id value to an output stream. This option should be
853 specified prior to the output filename to which it applies.
854 For the situation where multiple output files exist, a streamid
855 may be reassigned to a different value.
857 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
858 an output mpegts file:
860 avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
863 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
864 Set bitstream filters for matching streams. @var{bistream_filters} is
865 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
866 to get the list of bitstream filters.
868 avconv -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
871 avconv -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
874 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{input/output,per-stream})
875 Force a tag/fourcc for matching streams.
877 @item -filter_complex @var{filtergraph} (@emph{global})
878 Define a complex filter graph, i.e. one with arbitrary number of inputs and/or
879 outputs. For simple graphs -- those with one input and one output of the same
880 type -- see the @option{-filter} options. @var{filtergraph} is a description of
881 the filter graph, as described in @ref{Filtergraph syntax}.
883 Input link labels must refer to input streams using the
884 @code{[file_index:stream_specifier]} syntax (i.e. the same as @option{-map}
885 uses). If @var{stream_specifier} matches multiple streams, the first one will be
886 used. An unlabeled input will be connected to the first unused input stream of
889 Output link labels are referred to with @option{-map}. Unlabeled outputs are
890 added to the first output file.
892 Note that with this option it is possible to use only lavfi sources without
895 For example, to overlay an image over video
897 avconv -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
900 Here @code{[0:v]} refers to the first video stream in the first input file,
901 which is linked to the first (main) input of the overlay filter. Similarly the
902 first video stream in the second input is linked to the second (overlay) input
905 Assuming there is only one video stream in each input file, we can omit input
906 labels, so the above is equivalent to
908 avconv -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
912 Furthermore we can omit the output label and the single output from the filter
913 graph will be added to the output file automatically, so we can simply write
915 avconv -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
918 To generate 5 seconds of pure red video using lavfi @code{color} source:
920 avconv -filter_complex 'color=red' -t 5 out.mkv
923 @item -filter_complex_script @var{filename} (@emph{global})
924 This option is similar to @option{-filter_complex}, the only difference is that
925 its argument is the name of the file from which a complex filtergraph
926 description is to be read.
928 @item -accurate_seek (@emph{input})
929 This option enables or disables accurate seeking in input files with the
930 @option{-ss} option. It is enabled by default, so seeking is accurate when
931 transcoding. Use @option{-noaccurate_seek} to disable it, which may be useful
932 e.g. when copying some streams and transcoding the others.
942 For streaming at very low bitrate application, use a low frame rate
943 and a small GOP size. This is especially true for RealVideo where
944 the Linux player does not seem to be very fast, so it can miss
945 frames. An example is:
948 avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
952 The parameter 'q' which is displayed while encoding is the current
953 quantizer. The value 1 indicates that a very good quality could
954 be achieved. The value 31 indicates the worst quality. If q=31 appears
955 too often, it means that the encoder cannot compress enough to meet
956 your bitrate. You must either increase the bitrate, decrease the
957 frame rate or decrease the frame size.
960 If your computer is not fast enough, you can speed up the
961 compression at the expense of the compression ratio. You can use
962 '-me zero' to speed up motion estimation, and '-g 0' to disable
963 motion estimation completely (you have only I-frames, which means it
964 is about as good as JPEG compression).
967 To have very low audio bitrates, reduce the sampling frequency
968 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
971 To have a constant quality (but a variable bitrate), use the option
972 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
979 @c man begin EXAMPLES
981 @section Preset files
983 A preset file contains a sequence of @var{option=value} pairs, one for
984 each line, specifying a sequence of options which can be specified also on
985 the command line. Lines starting with the hash ('#') character are ignored and
986 are used to provide comments. Empty lines are also ignored. Check the
987 @file{presets} directory in the Libav source tree for examples.
989 Preset files are specified with the @code{pre} option, this option takes a
990 preset name as input. Avconv searches for a file named @var{preset_name}.avpreset in
991 the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.avconv}, and in
992 the data directory defined at configuration time (usually @file{$PREFIX/share/avconv})
993 in that order. For example, if the argument is @code{libx264-max}, it will
994 search for the file @file{libx264-max.avpreset}.
996 @section Video and Audio grabbing
998 If you specify the input format and device then avconv can grab video
1002 avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
1005 Note that you must activate the right video source and channel before
1006 launching avconv with any TV viewer such as
1007 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
1008 have to set the audio recording levels correctly with a
1011 @section X11 grabbing
1013 Grab the X11 display with avconv via
1016 avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
1019 0.0 is display.screen number of your X11 server, same as
1020 the DISPLAY environment variable.
1023 avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
1026 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
1027 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
1029 @section Video and Audio file format conversion
1031 Any supported file format and protocol can serve as input to avconv:
1036 You can use YUV files as input:
1039 avconv -i /tmp/test%d.Y /tmp/out.mpg
1042 It will use the files:
1044 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
1045 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
1048 The Y files use twice the resolution of the U and V files. They are
1049 raw files, without header. They can be generated by all decent video
1050 decoders. You must specify the size of the image with the @option{-s} option
1051 if avconv cannot guess it.
1054 You can input from a raw YUV420P file:
1057 avconv -i /tmp/test.yuv /tmp/out.avi
1060 test.yuv is a file containing raw YUV planar data. Each frame is composed
1061 of the Y plane followed by the U and V planes at half vertical and
1062 horizontal resolution.
1065 You can output to a raw YUV420P file:
1068 avconv -i mydivx.avi hugefile.yuv
1072 You can set several input files and output files:
1075 avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
1078 Converts the audio file a.wav and the raw YUV video file a.yuv
1082 You can also do audio and video conversions at the same time:
1085 avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
1088 Converts a.wav to MPEG audio at 22050 Hz sample rate.
1091 You can encode to several formats at the same time and define a
1092 mapping from input stream to output streams:
1095 avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
1098 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
1099 file:index' specifies which input stream is used for each output
1100 stream, in the order of the definition of output streams.
1103 You can transcode decrypted VOBs:
1106 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
1109 This is a typical DVD ripping example; the input is a VOB file, the
1110 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
1111 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
1112 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
1113 input video. Furthermore, the audio stream is MP3-encoded so you need
1114 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
1115 The mapping is particularly useful for DVD transcoding
1116 to get the desired audio language.
1118 NOTE: To see the supported input formats, use @code{avconv -formats}.
1121 You can extract images from a video, or create a video from many images:
1123 For extracting images from a video:
1125 avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
1128 This will extract one video frame per second from the video and will
1129 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1130 etc. Images will be rescaled to fit the new WxH values.
1132 If you want to extract just a limited number of frames, you can use the
1133 above command in combination with the -vframes or -t option, or in
1134 combination with -ss to start extracting from a certain point in time.
1136 For creating a video from many images:
1138 avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1141 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1142 composed of three digits padded with zeroes to express the sequence
1143 number. It is the same syntax supported by the C printf function, but
1144 only formats accepting a normal integer are suitable.
1147 You can put many streams of the same type in the output:
1150 avconv -i test1.avi -i test2.avi -map 1:1 -map 1:0 -map 0:1 -map 0:0 -c copy -y test12.nut
1153 The resulting output file @file{test12.nut} will contain the first four streams
1154 from the input files in reverse order.
1157 To force CBR video output:
1159 avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
1163 The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
1164 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
1166 avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
1173 @include decoders.texi
1174 @include encoders.texi
1175 @include demuxers.texi
1176 @include muxers.texi
1177 @include indevs.texi
1178 @include outdevs.texi
1179 @include protocols.texi
1180 @include bitstream_filters.texi
1181 @include filters.texi
1182 @include metadata.texi
1187 @settitle avconv video converter
1189 @c man begin SEEALSO
1190 avplay(1), avprobe(1) and the Libav HTML documentation
1193 @c man begin AUTHORS
1194 The Libav developers