mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-25 00:32:31 +00:00
832ba44d8d
r_frame_rate should in theory have something to do with input framerate,
but in practice it is often made up from thin air by lavf. So unless we
are targeting a constant output framerate, it's better to just use input
stream timebase.
Brings back dropped frames in nuv and cscd tests introduced in
cd1ad18a65
1063 lines
34 KiB
Plaintext
1063 lines
34 KiB
Plaintext
\input texinfo @c -*- texinfo -*-
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@settitle avconv Documentation
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@titlepage
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@center @titlefont{avconv Documentation}
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@end titlepage
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@top
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@contents
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@chapter Synopsis
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The generic syntax is:
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@example
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@c man begin SYNOPSIS
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avconv [global options] [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
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@c man end
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@end example
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@chapter Description
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@c man begin DESCRIPTION
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avconv is a very fast video and audio converter that can also grab from
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a live audio/video source. It can also convert between arbitrary sample
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rates and resize video on the fly with a high quality polyphase filter.
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avconv reads from an arbitrary number of input "files" (which can be regular
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files, pipes, network streams, grabbing devices, etc.), specified by the
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@code{-i} option, and writes to an arbitrary number of output "files", which are
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specified by a plain output filename. Anything found on the command line which
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cannot be interpreted as an option is considered to be an output filename.
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Each input or output file can in principle contain any number of streams of
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different types (video/audio/subtitle/attachment/data). Allowed number and/or
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types of streams can be limited by the container format. Selecting, which
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streams from which inputs go into output, is done either automatically or with
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the @code{-map} option (see the Stream selection chapter).
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To refer to input files in options, you must use their indices (0-based). E.g.
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the first input file is @code{0}, the second is @code{1} etc. Similarly, streams
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within a file are referred to by their indices. E.g. @code{2:3} refers to the
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fourth stream in the third input file. See also the Stream specifiers chapter.
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As a general rule, options are applied to the next specified
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file. Therefore, order is important, and you can have the same
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option on the command line multiple times. Each occurrence is
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then applied to the next input or output file.
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Exceptions from this rule are the global options (e.g. verbosity level),
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which should be specified first.
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Do not mix input and output files -- first specify all input files, then all
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output files. Also do not mix options which belong to different files. All
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options apply ONLY to the next input or output file and are reset between files.
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@itemize
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@item
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To set the video bitrate of the output file to 64kbit/s:
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@example
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avconv -i input.avi -b 64k output.avi
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@end example
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@item
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To force the frame rate of the output file to 24 fps:
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@example
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avconv -i input.avi -r 24 output.avi
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@end example
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@item
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To force the frame rate of the input file (valid for raw formats only)
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to 1 fps and the frame rate of the output file to 24 fps:
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@example
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avconv -r 1 -i input.m2v -r 24 output.avi
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@end example
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@end itemize
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The format option may be needed for raw input files.
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@c man end DESCRIPTION
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@chapter Stream selection
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@c man begin STREAM SELECTION
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By default avconv tries to pick the "best" stream of each type present in input
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files and add them to each output file. For video, this means the highest
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resolution, for audio the highest channel count. For subtitle it's simply the
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first subtitle stream.
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You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
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full manual control, use the @code{-map} option, which disables the defaults just
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described.
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@c man end STREAM SELECTION
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@chapter Options
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@c man begin OPTIONS
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@include avtools-common-opts.texi
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@section Main options
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@table @option
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@item -f @var{fmt} (@emph{input/output})
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Force input or output file format. The format is normally autodetected for input
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files and guessed from file extension for output files, so this option is not
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needed in most cases.
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@item -i @var{filename} (@emph{input})
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input file name
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@item -y (@emph{global})
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Overwrite output files without asking.
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@item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
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@itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
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Select an encoder (when used before an output file) or a decoder (when used
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before an input file) for one or more streams. @var{codec} is the name of a
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decoder/encoder or a special value @code{copy} (output only) to indicate that
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the stream is not to be reencoded.
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For example
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@example
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avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
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@end example
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encodes all video streams with libx264 and copies all audio streams.
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For each stream, the last matching @code{c} option is applied, so
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@example
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avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
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@end example
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will copy all the streams except the second video, which will be encoded with
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libx264, and the 138th audio, which will be encoded with libvorbis.
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@item -t @var{duration} (@emph{output})
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Stop writing the output after its duration reaches @var{duration}.
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@var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
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@item -fs @var{limit_size} (@emph{output})
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Set the file size limit.
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@item -ss @var{position} (@emph{input/output})
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When used as an input option (before @code{-i}), seeks in this input file to
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@var{position}. When used as an output option (before an output filename),
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decodes but discards input until the timestamps reach @var{position}. This is
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slower, but more accurate.
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@var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
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@item -itsoffset @var{offset} (@emph{input})
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Set the input time offset in seconds.
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@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
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The offset is added to the timestamps of the input files.
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Specifying a positive offset means that the corresponding
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streams are delayed by @var{offset} seconds.
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@item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
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Set a metadata key/value pair.
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An optional @var{metadata_specifier} may be given to set metadata
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on streams or chapters. See @code{-map_metadata} documentation for
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details.
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This option overrides metadata set with @code{-map_metadata}. It is
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also possible to delete metadata by using an empty value.
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For example, for setting the title in the output file:
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@example
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avconv -i in.avi -metadata title="my title" out.flv
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@end example
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To set the language of the first audio stream:
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@example
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avconv -i INPUT -metadata:s:a:0 language=eng OUTPUT
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@end example
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@item -target @var{type} (@emph{output})
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Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
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@code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
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@code{film-} to use the corresponding standard. All the format options
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(bitrate, codecs, buffer sizes) are then set automatically. You can just type:
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@example
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avconv -i myfile.avi -target vcd /tmp/vcd.mpg
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@end example
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Nevertheless you can specify additional options as long as you know
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they do not conflict with the standard, as in:
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@example
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avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
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@end example
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@item -dframes @var{number} (@emph{output})
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Set the number of data frames to record. This is an alias for @code{-frames:d}.
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@item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
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Stop writing to the stream after @var{framecount} frames.
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@item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
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@itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
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Use fixed quality scale (VBR). The meaning of @var{q} is
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codec-dependent.
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@item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
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@var{filter_graph} is a description of the filter graph to apply to
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the stream. Use @code{-filters} to show all the available filters
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(including also sources and sinks).
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@item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
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Specify the preset for matching stream(s).
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@item -stats (@emph{global})
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Print encoding progress/statistics. On by default.
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@item -attach @var{filename} (@emph{output})
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Add an attachment to the output file. This is supported by a few formats
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like Matroska for e.g. fonts used in rendering subtitles. Attachments
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are implemented as a specific type of stream, so this option will add
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a new stream to the file. It is then possible to use per-stream options
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on this stream in the usual way. Attachment streams created with this
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option will be created after all the other streams (i.e. those created
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with @code{-map} or automatic mappings).
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Note that for Matroska you also have to set the mimetype metadata tag:
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@example
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avconv -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
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@end example
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(assuming that the attachment stream will be third in the output file).
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@item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
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Extract the matching attachment stream into a file named @var{filename}. If
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@var{filename} is empty, then the value of the @code{filename} metadata tag
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will be used.
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E.g. to extract the first attachment to a file named 'out.ttf':
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@example
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avconv -dump_attachment:t:0 out.ttf INPUT
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@end example
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To extract all attachments to files determined by the @code{filename} tag:
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@example
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avconv -dump_attachment:t "" INPUT
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@end example
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Technical note -- attachments are implemented as codec extradata, so this
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option can actually be used to extract extradata from any stream, not just
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attachments.
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@end table
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@section Video Options
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@table @option
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@item -vframes @var{number} (@emph{output})
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Set the number of video frames to record. This is an alias for @code{-frames:v}.
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@item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
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Set frame rate (Hz value, fraction or abbreviation), (default = 25). For output
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streams implies @code{-vsync cfr}.
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@item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
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Set frame size. The format is @samp{wxh} (default - same as source).
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The following abbreviations are recognized:
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@table @samp
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@item sqcif
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128x96
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@item qcif
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176x144
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@item cif
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352x288
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@item 4cif
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704x576
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@item 16cif
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1408x1152
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@item qqvga
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160x120
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@item qvga
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320x240
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@item vga
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640x480
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@item svga
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800x600
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@item xga
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1024x768
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@item uxga
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1600x1200
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@item qxga
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2048x1536
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@item sxga
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1280x1024
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@item qsxga
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2560x2048
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@item hsxga
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5120x4096
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@item wvga
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852x480
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@item wxga
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1366x768
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@item wsxga
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1600x1024
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@item wuxga
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1920x1200
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@item woxga
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2560x1600
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@item wqsxga
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3200x2048
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@item wquxga
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3840x2400
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@item whsxga
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6400x4096
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@item whuxga
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7680x4800
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@item cga
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320x200
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@item ega
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640x350
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@item hd480
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852x480
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@item hd720
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1280x720
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@item hd1080
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1920x1080
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@end table
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@item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
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Set the video display aspect ratio specified by @var{aspect}.
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@var{aspect} can be a floating point number string, or a string of the
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form @var{num}:@var{den}, where @var{num} and @var{den} are the
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numerator and denominator of the aspect ratio. For example "4:3",
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"16:9", "1.3333", and "1.7777" are valid argument values.
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@item -vn (@emph{output})
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Disable video recording.
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@item -bt @var{tolerance}
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Set video bitrate tolerance (in bits, default 4000k).
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Has a minimum value of: (target_bitrate/target_framerate).
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In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
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willing to deviate from the target average bitrate value. This is
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not related to min/max bitrate. Lowering tolerance too much has
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an adverse effect on quality.
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@item -maxrate @var{bitrate}
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Set max video bitrate (in bit/s).
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Requires -bufsize to be set.
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@item -minrate @var{bitrate}
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Set min video bitrate (in bit/s).
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Most useful in setting up a CBR encode:
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@example
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avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
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@end example
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It is of little use elsewise.
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@item -bufsize @var{size}
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Set video buffer verifier buffer size (in bits).
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@item -vcodec @var{codec} (@emph{output})
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Set the video codec. This is an alias for @code{-codec:v}.
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@item -same_quant
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Use same quantizer as source (implies VBR).
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Note that this is NOT SAME QUALITY. Do not use this option unless you know you
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need it.
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@item -pass @var{n}
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Select the pass number (1 or 2). It is used to do two-pass
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video encoding. The statistics of the video are recorded in the first
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pass into a log file (see also the option -passlogfile),
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and in the second pass that log file is used to generate the video
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at the exact requested bitrate.
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On pass 1, you may just deactivate audio and set output to null,
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examples for Windows and Unix:
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@example
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avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
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avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
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@end example
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@item -passlogfile @var{prefix} (@emph{global})
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Set two-pass log file name prefix to @var{prefix}, the default file name
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prefix is ``av2pass''. The complete file name will be
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@file{PREFIX-N.log}, where N is a number specific to the output
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stream.
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@item -vf @var{filter_graph} (@emph{output})
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@var{filter_graph} is a description of the filter graph to apply to
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the input video.
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Use the option "-filters" to show all the available filters (including
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also sources and sinks). This is an alias for @code{-filter:v}.
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@end table
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@section Advanced Video Options
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@table @option
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@item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
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Set pixel format. Use @code{-pix_fmts} to show all the supported
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pixel formats.
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@item -sws_flags @var{flags} (@emph{input/output})
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Set SwScaler flags.
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@item -g @var{gop_size}
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Set the group of pictures size.
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@item -vdt @var{n}
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Discard threshold.
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@item -qmin @var{q}
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minimum video quantizer scale (VBR)
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@item -qmax @var{q}
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maximum video quantizer scale (VBR)
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@item -qdiff @var{q}
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maximum difference between the quantizer scales (VBR)
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@item -qblur @var{blur}
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video quantizer scale blur (VBR) (range 0.0 - 1.0)
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@item -qcomp @var{compression}
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video quantizer scale compression (VBR) (default 0.5).
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Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
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@item -lmin @var{lambda}
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minimum video lagrange factor (VBR)
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@item -lmax @var{lambda}
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max video lagrange factor (VBR)
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@item -mblmin @var{lambda}
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minimum macroblock quantizer scale (VBR)
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@item -mblmax @var{lambda}
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maximum macroblock quantizer scale (VBR)
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These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
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but you may use the QP2LAMBDA constant to easily convert from 'q' units:
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@example
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avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
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@end example
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@item -rc_init_cplx @var{complexity}
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initial complexity for single pass encoding
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@item -b_qfactor @var{factor}
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qp factor between P- and B-frames
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@item -i_qfactor @var{factor}
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qp factor between P- and I-frames
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@item -b_qoffset @var{offset}
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qp offset between P- and B-frames
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@item -i_qoffset @var{offset}
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qp offset between P- and I-frames
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@item -rc_eq @var{equation}
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Set rate control equation (see section "Expression Evaluation")
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(default = @code{tex^qComp}).
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When computing the rate control equation expression, besides the
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standard functions defined in the section "Expression Evaluation", the
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following functions are available:
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@table @var
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@item bits2qp(bits)
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@item qp2bits(qp)
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@end table
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and the following constants are available:
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@table @var
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@item iTex
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@item pTex
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@item tex
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@item mv
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@item fCode
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@item iCount
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@item mcVar
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@item var
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@item isI
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@item isP
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@item isB
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@item avgQP
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@item qComp
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@item avgIITex
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@item avgPITex
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@item avgPPTex
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@item avgBPTex
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@item avgTex
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@end table
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@item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
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rate control override for specific intervals
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@item -me_method @var{method}
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Set motion estimation method to @var{method}.
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Available methods are (from lowest to best quality):
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@table @samp
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@item zero
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Try just the (0, 0) vector.
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@item phods
|
|
@item log
|
|
@item x1
|
|
@item hex
|
|
@item umh
|
|
@item epzs
|
|
(default method)
|
|
@item full
|
|
exhaustive search (slow and marginally better than epzs)
|
|
@end table
|
|
|
|
@item -er @var{n}
|
|
Set error resilience to @var{n}.
|
|
@table @samp
|
|
@item 1
|
|
FF_ER_CAREFUL (default)
|
|
@item 2
|
|
FF_ER_COMPLIANT
|
|
@item 3
|
|
FF_ER_AGGRESSIVE
|
|
@item 4
|
|
FF_ER_VERY_AGGRESSIVE
|
|
@end table
|
|
|
|
@item -ec @var{bit_mask}
|
|
Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
|
|
the following values:
|
|
@table @samp
|
|
@item 1
|
|
FF_EC_GUESS_MVS (default = enabled)
|
|
@item 2
|
|
FF_EC_DEBLOCK (default = enabled)
|
|
@end table
|
|
|
|
@item -bf @var{frames}
|
|
Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
|
|
@item -mbd @var{mode}
|
|
macroblock decision
|
|
@table @samp
|
|
@item 0
|
|
FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
|
|
@item 1
|
|
FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
|
|
@item 2
|
|
FF_MB_DECISION_RD: rate distortion
|
|
@end table
|
|
|
|
@item -bug @var{param}
|
|
Work around encoder bugs that are not auto-detected.
|
|
@item -strict @var{strictness}
|
|
How strictly to follow the standards.
|
|
|
|
@item -deinterlace
|
|
Deinterlace pictures.
|
|
This option is deprecated since the deinterlacing is very low quality.
|
|
Use the yadif filter with @code{-filter:v yadif}.
|
|
@item -vstats
|
|
Dump video coding statistics to @file{vstats_HHMMSS.log}.
|
|
@item -vstats_file @var{file}
|
|
Dump video coding statistics to @var{file}.
|
|
@item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
|
|
top=1/bottom=0/auto=-1 field first
|
|
@item -dc @var{precision}
|
|
Intra_dc_precision.
|
|
@item -vtag @var{fourcc/tag} (@emph{output})
|
|
Force video tag/fourcc. This is an alias for @code{-tag:v}.
|
|
@item -qphist (@emph{global})
|
|
Show QP histogram.
|
|
@item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
|
|
Force key frames at the specified timestamps, more precisely at the first
|
|
frames after each specified time.
|
|
This option can be useful to ensure that a seek point is present at a
|
|
chapter mark or any other designated place in the output file.
|
|
The timestamps must be specified in ascending order.
|
|
|
|
@item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
|
|
When doing stream copy, copy also non-key frames found at the
|
|
beginning.
|
|
@end table
|
|
|
|
@section Audio Options
|
|
|
|
@table @option
|
|
@item -aframes @var{number} (@emph{output})
|
|
Set the number of audio frames to record. This is an alias for @code{-frames:a}.
|
|
@item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
|
|
Set the audio sampling frequency. For output streams it is set by
|
|
default to the frequency of the corresponding input stream. For input
|
|
streams this option only makes sense for audio grabbing devices and raw
|
|
demuxers and is mapped to the corresponding demuxer options.
|
|
@item -aq @var{q} (@emph{output})
|
|
Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
|
|
@item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
|
|
Set the number of audio channels. For output streams it is set by
|
|
default to the number of input audio channels. For input streams
|
|
this option only makes sense for audio grabbing devices and raw demuxers
|
|
and is mapped to the corresponding demuxer options.
|
|
@item -an (@emph{output})
|
|
Disable audio recording.
|
|
@item -acodec @var{codec} (@emph{input/output})
|
|
Set the audio codec. This is an alias for @code{-codec:a}.
|
|
@item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
|
|
Set the audio sample format. Use @code{-sample_fmts} to get a list
|
|
of supported sample formats.
|
|
@end table
|
|
|
|
@section Advanced Audio options:
|
|
|
|
@table @option
|
|
@item -atag @var{fourcc/tag} (@emph{output})
|
|
Force audio tag/fourcc. This is an alias for @code{-tag:a}.
|
|
@item -audio_service_type @var{type}
|
|
Set the type of service that the audio stream contains.
|
|
@table @option
|
|
@item ma
|
|
Main Audio Service (default)
|
|
@item ef
|
|
Effects
|
|
@item vi
|
|
Visually Impaired
|
|
@item hi
|
|
Hearing Impaired
|
|
@item di
|
|
Dialogue
|
|
@item co
|
|
Commentary
|
|
@item em
|
|
Emergency
|
|
@item vo
|
|
Voice Over
|
|
@item ka
|
|
Karaoke
|
|
@end table
|
|
@end table
|
|
|
|
@section Subtitle options:
|
|
|
|
@table @option
|
|
@item -scodec @var{codec} (@emph{input/output})
|
|
Set the subtitle codec. This is an alias for @code{-codec:s}.
|
|
@item -sn (@emph{output})
|
|
Disable subtitle recording.
|
|
@end table
|
|
|
|
@section Audio/Video grab options
|
|
|
|
@table @option
|
|
@item -isync (@emph{global})
|
|
Synchronize read on input.
|
|
@end table
|
|
|
|
@section Advanced options
|
|
|
|
@table @option
|
|
@item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output})
|
|
|
|
Designate one or more input streams as a source for the output file. Each input
|
|
stream is identified by the input file index @var{input_file_id} and
|
|
the input stream index @var{input_stream_id} within the input
|
|
file. Both indices start at 0. If specified,
|
|
@var{sync_file_id}:@var{stream_specifier} sets which input stream
|
|
is used as a presentation sync reference.
|
|
|
|
The first @code{-map} option on the command line specifies the
|
|
source for output stream 0, the second @code{-map} option specifies
|
|
the source for output stream 1, etc.
|
|
|
|
A @code{-} character before the stream identifier creates a "negative" mapping.
|
|
It disables matching streams from already created mappings.
|
|
|
|
For example, to map ALL streams from the first input file to output
|
|
@example
|
|
avconv -i INPUT -map 0 output
|
|
@end example
|
|
|
|
For example, if you have two audio streams in the first input file,
|
|
these streams are identified by "0:0" and "0:1". You can use
|
|
@code{-map} to select which streams to place in an output file. For
|
|
example:
|
|
@example
|
|
avconv -i INPUT -map 0:1 out.wav
|
|
@end example
|
|
will map the input stream in @file{INPUT} identified by "0:1" to
|
|
the (single) output stream in @file{out.wav}.
|
|
|
|
For example, to select the stream with index 2 from input file
|
|
@file{a.mov} (specified by the identifier "0:2"), and stream with
|
|
index 6 from input @file{b.mov} (specified by the identifier "1:6"),
|
|
and copy them to the output file @file{out.mov}:
|
|
@example
|
|
avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
|
|
@end example
|
|
|
|
To select all video and the third audio stream from an input file:
|
|
@example
|
|
avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT
|
|
@end example
|
|
|
|
To map all the streams except the second audio, use negative mappings
|
|
@example
|
|
avconv -i INPUT -map 0 -map -0:a:1 OUTPUT
|
|
@end example
|
|
|
|
Note that using this option disables the default mappings for this output file.
|
|
|
|
@item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
|
|
Set metadata information of the next output file from @var{infile}. Note that
|
|
those are file indices (zero-based), not filenames.
|
|
Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
|
|
A metadata specifier can have the following forms:
|
|
@table @option
|
|
@item @var{g}
|
|
global metadata, i.e. metadata that applies to the whole file
|
|
|
|
@item @var{s}[:@var{stream_spec}]
|
|
per-stream metadata. @var{stream_spec} is a stream specifier as described
|
|
in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
|
|
matching stream is copied from. In an output metadata specifier, all matching
|
|
streams are copied to.
|
|
|
|
@item @var{c}:@var{chapter_index}
|
|
per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
|
|
|
|
@item @var{p}:@var{program_index}
|
|
per-program metadata. @var{program_index} is the zero-based program index.
|
|
@end table
|
|
If metadata specifier is omitted, it defaults to global.
|
|
|
|
By default, global metadata is copied from the first input file,
|
|
per-stream and per-chapter metadata is copied along with streams/chapters. These
|
|
default mappings are disabled by creating any mapping of the relevant type. A negative
|
|
file index can be used to create a dummy mapping that just disables automatic copying.
|
|
|
|
For example to copy metadata from the first stream of the input file to global metadata
|
|
of the output file:
|
|
@example
|
|
avconv -i in.ogg -map_metadata 0:s:0 out.mp3
|
|
@end example
|
|
|
|
To do the reverse, i.e. copy global metadata to all audio streams:
|
|
@example
|
|
avconv -i in.mkv -map_metadata:s:a 0:g out.mkv
|
|
@end example
|
|
Note that simple @code{0} would work as well in this example, since global
|
|
metadata is assumed by default.
|
|
|
|
@item -map_chapters @var{input_file_index} (@emph{output})
|
|
Copy chapters from input file with index @var{input_file_index} to the next
|
|
output file. If no chapter mapping is specified, then chapters are copied from
|
|
the first input file with at least one chapter. Use a negative file index to
|
|
disable any chapter copying.
|
|
@item -debug
|
|
Print specific debug info.
|
|
@item -benchmark (@emph{global})
|
|
Show benchmarking information at the end of an encode.
|
|
Shows CPU time used and maximum memory consumption.
|
|
Maximum memory consumption is not supported on all systems,
|
|
it will usually display as 0 if not supported.
|
|
@item -timelimit @var{duration} (@emph{global})
|
|
Exit after avconv has been running for @var{duration} seconds.
|
|
@item -dump (@emph{global})
|
|
Dump each input packet to stderr.
|
|
@item -hex (@emph{global})
|
|
When dumping packets, also dump the payload.
|
|
@item -ps @var{size}
|
|
Set RTP payload size in bytes.
|
|
@item -re (@emph{input})
|
|
Read input at native frame rate. Mainly used to simulate a grab device.
|
|
@item -threads @var{count}
|
|
Thread count.
|
|
@item -vsync @var{parameter}
|
|
Video sync method.
|
|
|
|
@table @option
|
|
@item passthrough
|
|
Each frame is passed with its timestamp from the demuxer to the muxer.
|
|
@item cfr
|
|
Frames will be duplicated and dropped to achieve exactly the requested
|
|
constant framerate.
|
|
@item vfr
|
|
Frames are passed through with their timestamp or dropped so as to
|
|
prevent 2 frames from having the same timestamp.
|
|
@item auto
|
|
Chooses between 1 and 2 depending on muxer capabilities. This is the
|
|
default method.
|
|
@end table
|
|
|
|
With -map you can select from which stream the timestamps should be
|
|
taken. You can leave either video or audio unchanged and sync the
|
|
remaining stream(s) to the unchanged one.
|
|
|
|
@item -async @var{samples_per_second}
|
|
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
|
|
the parameter is the maximum samples per second by which the audio is changed.
|
|
-async 1 is a special case where only the start of the audio stream is corrected
|
|
without any later correction.
|
|
@item -copyts
|
|
Copy timestamps from input to output.
|
|
@item -copytb
|
|
Copy input stream time base from input to output when stream copying.
|
|
@item -shortest
|
|
Finish encoding when the shortest input stream ends.
|
|
@item -dts_delta_threshold
|
|
Timestamp discontinuity delta threshold.
|
|
@item -muxdelay @var{seconds} (@emph{input})
|
|
Set the maximum demux-decode delay.
|
|
@item -muxpreload @var{seconds} (@emph{input})
|
|
Set the initial demux-decode delay.
|
|
@item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
|
|
Assign a new stream-id value to an output stream. This option should be
|
|
specified prior to the output filename to which it applies.
|
|
For the situation where multiple output files exist, a streamid
|
|
may be reassigned to a different value.
|
|
|
|
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
|
|
an output mpegts file:
|
|
@example
|
|
avconv -i infile -streamid 0:33 -streamid 1:36 out.ts
|
|
@end example
|
|
|
|
@item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
|
|
Set bitstream filters for matching streams. @var{bistream_filters} is
|
|
a comma-separated list of bitstream filters. Use the @code{-bsfs} option
|
|
to get the list of bitstream filters.
|
|
@example
|
|
avconv -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
|
|
@end example
|
|
@example
|
|
avconv -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
|
|
@end example
|
|
|
|
@item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{output,per-stream})
|
|
Force a tag/fourcc for matching streams.
|
|
@end table
|
|
@c man end OPTIONS
|
|
|
|
@chapter Tips
|
|
@c man begin TIPS
|
|
|
|
@itemize
|
|
@item
|
|
For streaming at very low bitrate application, use a low frame rate
|
|
and a small GOP size. This is especially true for RealVideo where
|
|
the Linux player does not seem to be very fast, so it can miss
|
|
frames. An example is:
|
|
|
|
@example
|
|
avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
|
|
@end example
|
|
|
|
@item
|
|
The parameter 'q' which is displayed while encoding is the current
|
|
quantizer. The value 1 indicates that a very good quality could
|
|
be achieved. The value 31 indicates the worst quality. If q=31 appears
|
|
too often, it means that the encoder cannot compress enough to meet
|
|
your bitrate. You must either increase the bitrate, decrease the
|
|
frame rate or decrease the frame size.
|
|
|
|
@item
|
|
If your computer is not fast enough, you can speed up the
|
|
compression at the expense of the compression ratio. You can use
|
|
'-me zero' to speed up motion estimation, and '-intra' to disable
|
|
motion estimation completely (you have only I-frames, which means it
|
|
is about as good as JPEG compression).
|
|
|
|
@item
|
|
To have very low audio bitrates, reduce the sampling frequency
|
|
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
|
|
|
|
@item
|
|
To have a constant quality (but a variable bitrate), use the option
|
|
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
|
|
quality).
|
|
|
|
@end itemize
|
|
@c man end TIPS
|
|
|
|
@chapter Examples
|
|
@c man begin EXAMPLES
|
|
|
|
@section Preset files
|
|
|
|
A preset file contains a sequence of @var{option=value} pairs, one for
|
|
each line, specifying a sequence of options which can be specified also on
|
|
the command line. Lines starting with the hash ('#') character are ignored and
|
|
are used to provide comments. Empty lines are also ignored. Check the
|
|
@file{presets} directory in the Libav source tree for examples.
|
|
|
|
Preset files are specified with the @code{pre} option, this option takes a
|
|
preset name as input. Avconv searches for a file named @var{preset_name}.avpreset in
|
|
the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.avconv}, and in
|
|
the data directory defined at configuration time (usually @file{$PREFIX/share/avconv})
|
|
in that order. For example, if the argument is @code{libx264-max}, it will
|
|
search for the file @file{libx264-max.avpreset}.
|
|
|
|
@section Video and Audio grabbing
|
|
|
|
If you specify the input format and device then avconv can grab video
|
|
and audio directly.
|
|
|
|
@example
|
|
avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
|
|
@end example
|
|
|
|
Note that you must activate the right video source and channel before
|
|
launching avconv with any TV viewer such as
|
|
@uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
|
|
have to set the audio recording levels correctly with a
|
|
standard mixer.
|
|
|
|
@section X11 grabbing
|
|
|
|
Grab the X11 display with avconv via
|
|
|
|
@example
|
|
avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
|
|
@end example
|
|
|
|
0.0 is display.screen number of your X11 server, same as
|
|
the DISPLAY environment variable.
|
|
|
|
@example
|
|
avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
|
|
@end example
|
|
|
|
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
|
|
variable. 10 is the x-offset and 20 the y-offset for the grabbing.
|
|
|
|
@section Video and Audio file format conversion
|
|
|
|
Any supported file format and protocol can serve as input to avconv:
|
|
|
|
Examples:
|
|
@itemize
|
|
@item
|
|
You can use YUV files as input:
|
|
|
|
@example
|
|
avconv -i /tmp/test%d.Y /tmp/out.mpg
|
|
@end example
|
|
|
|
It will use the files:
|
|
@example
|
|
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
|
|
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
|
|
@end example
|
|
|
|
The Y files use twice the resolution of the U and V files. They are
|
|
raw files, without header. They can be generated by all decent video
|
|
decoders. You must specify the size of the image with the @option{-s} option
|
|
if avconv cannot guess it.
|
|
|
|
@item
|
|
You can input from a raw YUV420P file:
|
|
|
|
@example
|
|
avconv -i /tmp/test.yuv /tmp/out.avi
|
|
@end example
|
|
|
|
test.yuv is a file containing raw YUV planar data. Each frame is composed
|
|
of the Y plane followed by the U and V planes at half vertical and
|
|
horizontal resolution.
|
|
|
|
@item
|
|
You can output to a raw YUV420P file:
|
|
|
|
@example
|
|
avconv -i mydivx.avi hugefile.yuv
|
|
@end example
|
|
|
|
@item
|
|
You can set several input files and output files:
|
|
|
|
@example
|
|
avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
|
|
@end example
|
|
|
|
Converts the audio file a.wav and the raw YUV video file a.yuv
|
|
to MPEG file a.mpg.
|
|
|
|
@item
|
|
You can also do audio and video conversions at the same time:
|
|
|
|
@example
|
|
avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2
|
|
@end example
|
|
|
|
Converts a.wav to MPEG audio at 22050 Hz sample rate.
|
|
|
|
@item
|
|
You can encode to several formats at the same time and define a
|
|
mapping from input stream to output streams:
|
|
|
|
@example
|
|
avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2
|
|
@end example
|
|
|
|
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
|
|
file:index' specifies which input stream is used for each output
|
|
stream, in the order of the definition of output streams.
|
|
|
|
@item
|
|
You can transcode decrypted VOBs:
|
|
|
|
@example
|
|
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
|
|
@end example
|
|
|
|
This is a typical DVD ripping example; the input is a VOB file, the
|
|
output an AVI file with MPEG-4 video and MP3 audio. Note that in this
|
|
command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
|
|
GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
|
|
input video. Furthermore, the audio stream is MP3-encoded so you need
|
|
to enable LAME support by passing @code{--enable-libmp3lame} to configure.
|
|
The mapping is particularly useful for DVD transcoding
|
|
to get the desired audio language.
|
|
|
|
NOTE: To see the supported input formats, use @code{avconv -formats}.
|
|
|
|
@item
|
|
You can extract images from a video, or create a video from many images:
|
|
|
|
For extracting images from a video:
|
|
@example
|
|
avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
|
|
@end example
|
|
|
|
This will extract one video frame per second from the video and will
|
|
output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
|
|
etc. Images will be rescaled to fit the new WxH values.
|
|
|
|
If you want to extract just a limited number of frames, you can use the
|
|
above command in combination with the -vframes or -t option, or in
|
|
combination with -ss to start extracting from a certain point in time.
|
|
|
|
For creating a video from many images:
|
|
@example
|
|
avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
|
|
@end example
|
|
|
|
The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
|
|
composed of three digits padded with zeroes to express the sequence
|
|
number. It is the same syntax supported by the C printf function, but
|
|
only formats accepting a normal integer are suitable.
|
|
|
|
@item
|
|
You can put many streams of the same type in the output:
|
|
|
|
@example
|
|
avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
|
|
@end example
|
|
|
|
The resulting output file @file{test12.avi} will contain first four streams from
|
|
the input file in reverse order.
|
|
|
|
@end itemize
|
|
@c man end EXAMPLES
|
|
|
|
@include eval.texi
|
|
@include encoders.texi
|
|
@include demuxers.texi
|
|
@include muxers.texi
|
|
@include indevs.texi
|
|
@include outdevs.texi
|
|
@include protocols.texi
|
|
@include bitstream_filters.texi
|
|
@include filters.texi
|
|
@include metadata.texi
|
|
|
|
@ignore
|
|
|
|
@setfilename avconv
|
|
@settitle avconv video converter
|
|
|
|
@c man begin SEEALSO
|
|
avplay(1), avprobe(1) and the Libav HTML documentation
|
|
@c man end
|
|
|
|
@c man begin AUTHORS
|
|
The Libav developers
|
|
@c man end
|
|
|
|
@end ignore
|
|
|
|
@bye
|