Merge remote-tracking branch 'TimothyGu/release/1.2' into release/1.2
* TimothyGu/release/1.2: doc/encoders: add doc for AAC encoder doc/encoders: improve libvo-aacenc doc doc/ffmpeg-formats: Add documentation for 3 parameters that have been missing doc/encoders: Remove options that were not there when branch was cut from master doc/encoders: reformat and add some clarification in libtwolame doc doc/encoders: reformat libmp3lame doc Merged-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
@@ -25,6 +25,95 @@ enabled encoders.
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A description of some of the currently available audio encoders
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A description of some of the currently available audio encoders
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follows.
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follows.
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@anchor{aacenc}
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@section aac
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Advanced Audio Coding (AAC) encoder.
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This encoder is an experimental FFmpeg-native AAC encoder. Currently only the
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low complexity (AAC-LC) profile is supported. To use this encoder, you must set
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@option{strict} option to @samp{experimental} or lower.
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As this encoder is experimental, unexpected behavior may exist from time to
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time. For a more stable AAC encoder, see @ref{libvo-aacenc}. However, be warned
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that it has a worse quality reported by some users.
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@c Comment this out until somebody writes the respective documentation.
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@c See also @ref{libfaac}, @ref{libaacplus}, and @ref{libfdk-aac-enc}.
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@subsection Options
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@table @option
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@item b
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Set bit rate in bits/s. Setting this automatically activates constant bit rate
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(CBR) mode.
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@item q
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Set quality for variable bit rate (VBR) mode. This option is valid only using
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the @command{ffmpeg} command-line tool. For library interface users, use
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@option{global_quality}.
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@item stereo_mode
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Set stereo encoding mode. Possible values:
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@table @samp
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@item auto
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Automatically selected by the encoder.
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@item ms_off
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Disable middle/side encoding. This is the default.
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@item ms_force
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Force middle/side encoding.
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@end table
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@item aac_coder
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Set AAC encoder coding method. Possible values:
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@table @samp
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@item 0
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FAAC-inspired method.
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This method is a simplified reimplementation of the method used in FAAC, which
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sets thresholds proportional to the band energies, and then decreases all the
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thresholds with quantizer steps to find the appropriate quantization with
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distortion below threshold band by band.
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The quality of this method is comparable to the two loop searching method
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descibed below, but somewhat a little better and slower.
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@item 1
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Average noise to mask ratio (ANMR) trellis-based solution.
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This has a theoretic best quality out of all the coding methods, but at the
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cost of the slowest speed.
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@item 2
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Two loop searching (TLS) method.
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This method first sets quantizers depending on band thresholds and then tries
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to find an optimal combination by adding or subtracting a specific value from
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all quantizers and adjusting some individual quantizer a little.
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This method produces similar quality with the FAAC method and is the default.
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@item 3
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Constant quantizer method.
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This method sets a constant quantizer for all bands. This is the fastest of all
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the methods, yet produces the worst quality.
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@end table
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@end table
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@subsection Tips and Tricks
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According to some reports
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(e.g. @url{http://d.hatena.ne.jp/kamedo2/20120729/1343545890}), setting the
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@option{cutoff} option to 15000 Hz greatly improves the quality of the output
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quality. As a result, we encourage you to do the same.
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@section ac3 and ac3_fixed
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@section ac3 and ac3_fixed
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AC-3 audio encoders.
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AC-3 audio encoders.
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@@ -420,26 +509,32 @@ Requires the presence of the libmp3lame headers and library during
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configuration. You need to explicitly configure the build with
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configuration. You need to explicitly configure the build with
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@code{--enable-libmp3lame}.
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@code{--enable-libmp3lame}.
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@subsection Option Mapping
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@subsection Options
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The following options are supported by the libmp3lame wrapper,
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The following options are supported by the libmp3lame wrapper. The
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the LAME-equivalent options follow the FFmpeg ones.
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@command{lame}-equivalent of the options are listed in parentheses.
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@multitable @columnfractions .2 .2
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@table @option
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@item FFmpeg @tab LAME
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@item b (@emph{-b})
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@item b @tab b
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Set bitrate expressed in bits/s for CBR. LAME @code{bitrate} is
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FFmpeg @code{b} option is expressed in bits/s, lame @code{bitrate}
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expressed in kilobits/s.
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in kilobits/s.
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@item q @tab V
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@item q (@emph{-V})
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Quality setting for VBR.
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Set constant quality setting for VBR. This option is valid only
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@item compression_level @tab q
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using the @command{ffmpeg} command-line tool. For library interface
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Algorithm quality. Valid options are integers from 0-9.
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users, use @option{global_quality}.
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@item reservoir @tab N.A.
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Enable use of bit reservoir. LAME has this enabled by default.
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@item compression_level (@emph{-q})
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@item joint_stereo @tab -m j
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Set algorithm quality. Valid arguments are integers in the 0-9 range,
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Enables the the encoder to use (on a frame by frame basis) either L/R
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with 0 meaning highest quality but slowest, and 9 meaning fastest
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stereo or mid/side stereo.
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while producing the worst quality.
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@end multitable
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@item reservoir
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Enable use of bit reservoir when set to 1. Default value is 1. LAME
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has this enabled by default, but can be overriden by use
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@option{--nores} option.
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@end table
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@section libopencore-amrnb
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@section libopencore-amrnb
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@@ -486,24 +581,26 @@ Requires the presence of the libtwolame headers and library during
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configuration. You need to explicitly configure the build with
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configuration. You need to explicitly configure the build with
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@code{--enable-libtwolame}.
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@code{--enable-libtwolame}.
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@subsection Options Mapping
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@subsection Options
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The following options are supported by the libtwolame wrapper. The
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The following options are supported by the libtwolame wrapper. The
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TwoLAME-equivalent options follow the FFmpeg ones and are in
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@command{twolame}-equivalent options follow the FFmpeg ones and are in
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parentheses.
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parentheses.
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@table @option
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@table @option
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@item b
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@item b (@emph{-b})
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(b) Set bitrate in bits/s. Note that FFmpeg @code{b} option is
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Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
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expressed in bits/s, twolame @code{b} in kilobits/s. The default
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option is expressed in kilobits/s. Default value is 128k.
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value is 128k.
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@item q
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@item q (@emph{-V})
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(V) Set quality for experimental VBR support. Maximum value range is
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Set quality for experimental VBR support. Maximum value range is
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from -50 to 50, useful range is from -10 to 10.
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from -50 to 50, useful range is from -10 to 10. The higher the
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value, the better the quality. This option is valid only using the
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@command{ffmpeg} command-line tool. For library interface users,
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use @option{global_quality}.
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@item mode
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@item mode (@emph{--mode})
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(mode) Set MPEG mode. Possible values:
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Set the mode of the resulting audio. Possible values:
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@table @samp
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@table @samp
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@item auto
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@item auto
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@@ -518,29 +615,30 @@ Dual channel
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Mono
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Mono
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@end table
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@end table
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@item psymodel
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@item psymodel (@emph{--psyc-mode})
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(psyc-mode) Set psychoacoustic model to use in encoding. The argument
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Set psychoacoustic model to use in encoding. The argument must be
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must be an integer between -1 and 4, inclusive. The higher the value,
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an integer between -1 and 4, inclusive. The higher the value, the
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the better the quality. The default value is 3.
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better the quality. The default value is 3.
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@item energy_levels
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@item energy_levels (@emph{--energy})
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(energy) Enable energy levels extensions when set to 1. The default
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Enable energy levels extensions when set to 1. The default value is
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value is 0 (disabled).
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0 (disabled).
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@item error_protection
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@item error_protection (@emph{--protect})
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(protect) Enable CRC error protection when set to 1. The default value
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Enable CRC error protection when set to 1. The default value is 0
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is 0 (disabled).
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(disabled).
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@item copyright
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@item copyright (@emph{--copyright})
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(copyright) Set MPEG audio copyright flag when set to 1. The default
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Set MPEG audio copyright flag when set to 1. The default value is 0
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value is 0 (disabled).
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(disabled).
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@item original
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@item original (@emph{--original})
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(original) Set MPEG audio original flag when set to 1. The default
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Set MPEG audio original flag when set to 1. The default value is 0
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value is 0 (disabled).
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(disabled).
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@end table
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@end table
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@anchor{libvo-aacenc}
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@section libvo-aacenc
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@section libvo-aacenc
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VisualOn AAC encoder
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VisualOn AAC encoder
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@@ -549,16 +647,19 @@ Requires the presence of the libvo-aacenc headers and library during
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configuration. You need to explicitly configure the build with
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configuration. You need to explicitly configure the build with
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@code{--enable-libvo-aacenc --enable-version3}.
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@code{--enable-libvo-aacenc --enable-version3}.
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This encoder is considered to be worse than the
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@ref{aacenc,,native experimental FFmpeg AAC encoder}, according to
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multiple sources.
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@subsection Options
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@subsection Options
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The VisualOn AAC encoder only support encoding AAC-LC and up to 2
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The VisualOn AAC encoder only support encoding AAC-LC and up to 2
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channels. It is also CBR-only. It is considered to be worse than the
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channels. It is also CBR-only.
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native experimental FFmpeg AAC encoder.
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@table @option
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@table @option
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@item b
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@item b
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Bitrate.
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Set bit rate in bits/s.
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@end table
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@end table
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@@ -76,6 +76,9 @@ Enable RTP MP4A-LATM payload.
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Reduce the latency introduced by optional buffering
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Reduce the latency introduced by optional buffering
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@end table
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@end table
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@item seek2any @var{integer} (@emph{input})
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Forces seeking to enable seek to any mode if set to 1. Default is 0.
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@item analyzeduration @var{integer} (@emph{input})
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@item analyzeduration @var{integer} (@emph{input})
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Specify how many microseconds are analyzed to probe the input. A
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Specify how many microseconds are analyzed to probe the input. A
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higher value will allow to detect more accurate information, but will
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higher value will allow to detect more accurate information, but will
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@@ -142,6 +145,12 @@ Use wallclock as timestamps.
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@item avoid_negative_ts @var{integer} (@emph{output})
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@item avoid_negative_ts @var{integer} (@emph{output})
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Shift timestamps to make them positive. 1 enables, 0 disables, default
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Shift timestamps to make them positive. 1 enables, 0 disables, default
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of -1 enables when required by target format.
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of -1 enables when required by target format.
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@item skip_initial_bytes @var{integer} (@emph{input})
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Set number initial bytes to skip. Default is 0.
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@item correct_ts_overflow @var{integer} (@emph{input})
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Correct single timestamp overflows if set to 1. Default is 1.
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@end table
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@end table
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@c man end FORMAT OPTIONS
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@c man end FORMAT OPTIONS
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