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\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 [[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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The command line interface is designed to be intuitive, in the sense |
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that avconv tries to figure out all parameters that can possibly be |
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derived automatically. You usually only have to specify the target |
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bitrate you want. |
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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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@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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By default avconv tries to convert as losslessly as possible: It |
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uses the same audio and video parameters for the outputs as the one |
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specified for the inputs. |
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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 fftools-common-opts.texi |
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@section Main options |
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@table @option |
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@item -f @var{fmt} |
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Force format. |
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@item -i @var{filename} |
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input file name |
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@item -y |
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Overwrite output files. |
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@item -c[:@var{stream_type}][:@var{stream_index}] @var{codec} |
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@item -codec[:@var{stream_type}][:@var{stream_index}] @var{codec} |
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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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@var{stream_type} may be 'v' for video, 'a' for audio, 's' for subtitle and 'd' |
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for data streams. @var{stream_index} is a global zero-based stream index if |
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@var{stream_type} isn't given, otherwise it counts only streams of the given |
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type. If @var{stream_index} is omitted, this option applies to all streams of |
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the given type or all streams of any type if @var{stream_type} is missing as |
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well (note that this only makes sense when all streams are of the same type or |
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@var{codec} is @code{copy}). |
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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} |
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Restrict the transcoded/captured video sequence |
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to the duration specified in seconds. |
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@code{hh:mm:ss[.xxx]} syntax is also supported. |
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@item -fs @var{limit_size} |
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Set the file size limit. |
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@item -ss @var{position} |
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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} |
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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 'offset' seconds. |
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@item -timestamp @var{time} |
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Set the recording timestamp in the container. |
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The syntax for @var{time} is: |
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@example |
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now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z]) |
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@end example |
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If the value is "now" it takes the current time. |
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Time is local time unless 'Z' or 'z' is appended, in which case it is |
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interpreted as UTC. |
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If the year-month-day part is not specified it takes the current |
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year-month-day. |
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@item -metadata[:metadata_specifier] @var{key}=@var{value} |
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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 second stream: |
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@example |
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avconv -i INPUT -metadata:s:1 language=eng OUTPUT |
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@end example |
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@item -v @var{number} |
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Set the logging verbosity level. |
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@item -target @var{type} |
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Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd", |
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"ntsc-svcd", ... ). All the format options (bitrate, codecs, |
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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} |
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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 -slang @var{code} |
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Set the ISO 639 language code (3 letters) of the current subtitle stream. |
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@item -frames[:stream_specifier] @var{framecount} |
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Stop writing to the stream after @var{framecount} frames. |
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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} |
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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{fps} |
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Set frame rate (Hz value, fraction or abbreviation), (default = 25). |
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@item -s @var{size} |
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Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv 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{aspect} |
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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 |
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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} |
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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} |
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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 -vlang @var{code} |
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Set the ISO 639 language code (3 letters) of the current video stream. |
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@item -vf @var{filter_graph} |
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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). |
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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{format} |
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Set pixel format. Use 'list' as parameter to show all the supported |
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pixel formats. |
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@item -sws_flags @var{flags} |
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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 -qscale @var{q} |
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Use fixed video quantizer scale (VBR). |
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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{override} |
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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 |
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@item log |
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@item x1 |
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@item hex |
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@item umh |
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@item epzs |
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(default method) |
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@item full |
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exhaustive search (slow and marginally better than epzs) |
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@end table |
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@item -dct_algo @var{algo} |
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Set DCT algorithm to @var{algo}. Available values are: |
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@table @samp |
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@item 0 |
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FF_DCT_AUTO (default) |
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@item 1 |
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FF_DCT_FASTINT |
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@item 2 |
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FF_DCT_INT |
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@item 3 |
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FF_DCT_MMX |
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@item 4 |
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FF_DCT_MLIB |
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@item 5 |
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FF_DCT_ALTIVEC |
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@end table |
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@item -idct_algo @var{algo} |
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Set IDCT algorithm to @var{algo}. Available values are: |
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@table @samp |
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@item 0 |
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FF_IDCT_AUTO (default) |
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@item 1 |
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FF_IDCT_INT |
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@item 2 |
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FF_IDCT_SIMPLE |
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@item 3 |
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FF_IDCT_SIMPLEMMX |
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@item 4 |
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FF_IDCT_LIBMPEG2MMX |
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@item 5 |
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FF_IDCT_PS2 |
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@item 6 |
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FF_IDCT_MLIB |
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@item 7 |
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FF_IDCT_ARM |
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@item 8 |
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FF_IDCT_ALTIVEC |
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@item 9 |
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FF_IDCT_SH4 |
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@item 10 |
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FF_IDCT_SIMPLEARM |
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@end table |
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@item -er @var{n} |
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Set error resilience to @var{n}. |
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@table @samp |
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@item 1 |
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FF_ER_CAREFUL (default) |
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@item 2 |
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FF_ER_COMPLIANT |
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@item 3 |
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FF_ER_AGGRESSIVE |
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@item 4 |
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FF_ER_VERY_AGGRESSIVE |
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@end table |
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@item -ec @var{bit_mask} |
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Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of |
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the following values: |
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@table @samp |
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@item 1 |
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FF_EC_GUESS_MVS (default = enabled) |
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@item 2 |
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FF_EC_DEBLOCK (default = enabled) |
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@end table |
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@item -bf @var{frames} |
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Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4). |
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@item -mbd @var{mode} |
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macroblock decision |
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@table @samp |
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@item 0 |
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FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv). |
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@item 1 |
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FF_MB_DECISION_BITS: Choose the one which needs the fewest bits. |
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@item 2 |
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FF_MB_DECISION_RD: rate distortion |
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@end table |
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@item -4mv |
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Use four motion vector by macroblock (MPEG-4 only). |
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@item -part |
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Use data partitioning (MPEG-4 only). |
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@item -bug @var{param} |
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Work around encoder bugs that are not auto-detected. |
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@item -strict @var{strictness} |
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How strictly to follow the standards. |
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@item -aic |
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Enable Advanced intra coding (h263+). |
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@item -umv |
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Enable Unlimited Motion Vector (h263+) |
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@item -deinterlace |
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Deinterlace pictures. |
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@item -ilme |
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Force interlacing support in encoder (MPEG-2 and MPEG-4 only). |
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Use this option if your input file is interlaced and you want |
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to keep the interlaced format for minimum losses. |
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The alternative is to deinterlace the input stream with |
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@option{-deinterlace}, but deinterlacing introduces losses. |
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@item -psnr |
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Calculate PSNR of compressed frames. |
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@item -vstats |
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Dump video coding statistics to @file{vstats_HHMMSS.log}. |
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@item -vstats_file @var{file} |
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Dump video coding statistics to @var{file}. |
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@item -top @var{n} |
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top=1/bottom=0/auto=-1 field first |
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@item -dc @var{precision} |
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Intra_dc_precision. |
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@item -vtag @var{fourcc/tag} |
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Force video tag/fourcc. |
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@item -qphist |
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Show QP histogram. |
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@item -force_key_frames @var{time}[,@var{time}...] |
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Force key frames at the specified timestamps, more precisely at the first |
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frames after each specified time. |
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This option can be useful to ensure that a seek point is present at a |
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chapter mark or any other designated place in the output file. |
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The timestamps must be specified in ascending order. |
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@end table |
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@section Audio Options |
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@table @option |
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@item -aframes @var{number} |
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Set the number of audio frames to record. This is an alias for @code{-frames:a}. |
|
@item -ar @var{freq} |
|
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} |
|
Set the audio quality (codec-specific, VBR). |
|
@item -ac @var{channels} |
|
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 |
|
Disable audio recording. |
|
@item -acodec @var{codec} |
|
Set the audio codec. This is an alias for @code{-codec:a}. |
|
@item -alang @var{code} |
|
Set the ISO 639 language code (3 letters) of the current audio stream. |
|
@end table |
|
|
|
@section Advanced Audio options: |
|
|
|
@table @option |
|
@item -atag @var{fourcc/tag} |
|
Force audio tag/fourcc. |
|
@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} |
|
Set the subtitle codec. This is an alias for @code{-codec:s}. |
|
@item -slang @var{code} |
|
Set the ISO 639 language code (3 letters) of the current subtitle stream. |
|
@item -sn |
|
Disable subtitle recording. |
|
@end table |
|
|
|
@section Audio/Video grab options |
|
|
|
@table @option |
|
@item -isync |
|
Synchronize read on input. |
|
@end table |
|
|
|
@section Advanced options |
|
|
|
@table @option |
|
@item -map [-]@var{input_file_id}[:@var{input_stream_type}][:@var{input_stream_id}][,@var{sync_file_id}[:@var{sync_stream_type}][:@var{sync_stream_id}]] |
|
|
|
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{sync_stream_id} sets which input stream |
|
is used as a presentation sync reference. |
|
|
|
If @var{input_stream_type} is specified -- 'v' for video, 'a' for audio, 's' for |
|
subtitle and 'd' for data -- then @var{input_stream_id} counts only the streams |
|
of this type. Same for @var{sync_stream_type}. |
|
|
|
@var{input_stream_id} may be omitted, in which case all streams of the given |
|
type are mapped (or all streams in the file, if no type is specified). |
|
|
|
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_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] |
|
Set metadata information of the next output file from @var{infile}. Note that |
|
those are file indices (zero-based), not filenames. |
|
Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal |
|
(i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or |
|
per-(p)rogram. All metadata specifiers other than global must be followed by the |
|
stream/chapter/program index. 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 |
|
@item -map_chapters @var{input_file_index} |
|
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 |
|
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 -dump |
|
Dump each input packet. |
|
@item -hex |
|
When dumping packets, also dump the payload. |
|
@item -bitexact |
|
Only use bit exact algorithms (for codec testing). |
|
@item -ps @var{size} |
|
Set RTP payload size in bytes. |
|
@item -re |
|
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 0 |
|
Each frame is passed with its timestamp from the demuxer to the muxer. |
|
@item 1 |
|
Frames will be duplicated and dropped to achieve exactly the requested |
|
constant framerate. |
|
@item 2 |
|
Frames are passed through with their timestamp or dropped so as to |
|
prevent 2 frames from having the same timestamp. |
|
@item -1 |
|
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} |
|
Set the maximum demux-decode delay. |
|
@item -muxpreload @var{seconds} |
|
Set the initial demux-decode delay. |
|
@item -streamid @var{output-stream-index}:@var{new-value} |
|
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} |
|
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 -vbsf h264_mp4toannexb -an out.h264 |
|
@end example |
|
@example |
|
avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt |
|
@end example |
|
@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 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), avserver(1) and the Libav HTML documentation |
|
@c man end |
|
|
|
@c man begin AUTHORS |
|
The Libav developers |
|
@c man end |
|
|
|
@end ignore |
|
|
|
@bye
|
|
|