diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2013-10-11 15:28:03 +0200 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2013-10-11 15:28:11 +0200 |
commit | eb3330b050ba8c9e4254d6331d670e8a98d1944a (patch) | |
tree | 31e80aceed31d87320833c2fbbfa03f5dd5cee68 | |
parent | e31e66948d0a9a3f98afdb49c63208caefed5a61 (diff) | |
parent | a4acb5b9003833109eaa4b72ef016062b368fe5a (diff) | |
download | ffmpeg-eb3330b050ba8c9e4254d6331d670e8a98d1944a.tar.gz |
Merge remote-tracking branch 'TimothyGu/release/1.1' into release/1.1
* TimothyGu/release/1.1:
doc/encoders: add doc for AAC encoder
doc/ffmpeg-formats: Add documentation for 2 parameters that have been missing
doc/encoders: improve libvo-aacenc doc
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>
-rw-r--r-- | doc/encoders.texi | 199 | ||||
-rw-r--r-- | doc/ffmpeg-formats.texi | 6 |
2 files changed, 156 insertions, 49 deletions
diff --git a/doc/encoders.texi b/doc/encoders.texi index 1f06dee2ac..32d77ee43d 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -25,6 +25,95 @@ enabled encoders. A description of some of the currently available audio encoders follows. +@anchor{aacenc} +@section aac + +Advanced Audio Coding (AAC) encoder. + +This encoder is an experimental FFmpeg-native AAC encoder. Currently only the +low complexity (AAC-LC) profile is supported. To use this encoder, you must set +@option{strict} option to @samp{experimental} or lower. + +As this encoder is experimental, unexpected behavior may exist from time to +time. For a more stable AAC encoder, see @ref{libvo-aacenc}. However, be warned +that it has a worse quality reported by some users. + +@c Comment this out until somebody writes the respective documentation. +@c See also @ref{libfaac}, @ref{libaacplus}, and @ref{libfdk-aac-enc}. + +@subsection Options + +@table @option +@item b +Set bit rate in bits/s. Setting this automatically activates constant bit rate +(CBR) mode. + +@item q +Set quality for variable bit rate (VBR) mode. This option is valid only using +the @command{ffmpeg} command-line tool. For library interface users, use +@option{global_quality}. + +@item stereo_mode +Set stereo encoding mode. Possible values: + +@table @samp +@item auto +Automatically selected by the encoder. + +@item ms_off +Disable middle/side encoding. This is the default. + +@item ms_force +Force middle/side encoding. +@end table + +@item aac_coder +Set AAC encoder coding method. Possible values: + +@table @samp +@item 0 +FAAC-inspired method. + +This method is a simplified reimplementation of the method used in FAAC, which +sets thresholds proportional to the band energies, and then decreases all the +thresholds with quantizer steps to find the appropriate quantization with +distortion below threshold band by band. + +The quality of this method is comparable to the two loop searching method +descibed below, but somewhat a little better and slower. + +@item 1 +Average noise to mask ratio (ANMR) trellis-based solution. + +This has a theoretic best quality out of all the coding methods, but at the +cost of the slowest speed. + +@item 2 +Two loop searching (TLS) method. + +This method first sets quantizers depending on band thresholds and then tries +to find an optimal combination by adding or subtracting a specific value from +all quantizers and adjusting some individual quantizer a little. + +This method produces similar quality with the FAAC method and is the default. + +@item 3 +Constant quantizer method. + +This method sets a constant quantizer for all bands. This is the fastest of all +the methods, yet produces the worst quality. + +@end table + +@end table + +@subsection Tips and Tricks + +According to some reports +(e.g. @url{http://d.hatena.ne.jp/kamedo2/20120729/1343545890}), setting the +@option{cutoff} option to 15000 Hz greatly improves the quality of the output +quality. As a result, we encourage you to do the same. + @section ac3 and ac3_fixed AC-3 audio encoders. @@ -420,26 +509,32 @@ Requires the presence of the libmp3lame headers and library during configuration. You need to explicitly configure the build with @code{--enable-libmp3lame}. -@subsection Option Mapping +@subsection Options + +The following options are supported by the libmp3lame wrapper. The +@command{lame}-equivalent of the options are listed in parentheses. + +@table @option +@item b (@emph{-b}) +Set bitrate expressed in bits/s for CBR. LAME @code{bitrate} is +expressed in kilobits/s. + +@item q (@emph{-V}) +Set constant quality setting for VBR. This option is valid only +using the @command{ffmpeg} command-line tool. For library interface +users, use @option{global_quality}. + +@item compression_level (@emph{-q}) +Set algorithm quality. Valid arguments are integers in the 0-9 range, +with 0 meaning highest quality but slowest, and 9 meaning fastest +while producing the worst quality. -The following options are supported by the libmp3lame wrapper, -the LAME-equivalent options follow the FFmpeg ones. - -@multitable @columnfractions .2 .2 -@item FFmpeg @tab LAME -@item b @tab b -FFmpeg @code{b} option is expressed in bits/s, lame @code{bitrate} -in kilobits/s. -@item q @tab V -Quality setting for VBR. -@item compression_level @tab q -Algorithm quality. Valid options are integers from 0-9. -@item reservoir @tab N.A. -Enable use of bit reservoir. LAME has this enabled by default. -@item joint_stereo @tab -m j -Enables the the encoder to use (on a frame by frame basis) either L/R -stereo or mid/side stereo. -@end multitable +@item reservoir +Enable use of bit reservoir when set to 1. Default value is 1. LAME +has this enabled by default, but can be overriden by use +@option{--nores} option. + +@end table @section libopencore-amrnb @@ -486,24 +581,26 @@ Requires the presence of the libtwolame headers and library during configuration. You need to explicitly configure the build with @code{--enable-libtwolame}. -@subsection Options Mapping +@subsection Options The following options are supported by the libtwolame wrapper. The -TwoLAME-equivalent options follow the FFmpeg ones and are in +@command{twolame}-equivalent options follow the FFmpeg ones and are in parentheses. @table @option -@item b -(b) Set bitrate in bits/s. Note that FFmpeg @code{b} option is -expressed in bits/s, twolame @code{b} in kilobits/s. The default -value is 128k. +@item b (@emph{-b}) +Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b} +option is expressed in kilobits/s. Default value is 128k. -@item q -(V) Set quality for experimental VBR support. Maximum value range is -from -50 to 50, useful range is from -10 to 10. +@item q (@emph{-V}) +Set quality for experimental VBR support. Maximum value range is +from -50 to 50, useful range is from -10 to 10. The higher the +value, the better the quality. This option is valid only using the +@command{ffmpeg} command-line tool. For library interface users, +use @option{global_quality}. -@item mode -(mode) Set MPEG mode. Possible values: +@item mode (@emph{--mode}) +Set the mode of the resulting audio. Possible values: @table @samp @item auto @@ -518,29 +615,30 @@ Dual channel Mono @end table -@item psymodel -(psyc-mode) Set psychoacoustic model to use in encoding. The argument -must be an integer between -1 and 4, inclusive. The higher the value, -the better the quality. The default value is 3. +@item psymodel (@emph{--psyc-mode}) +Set psychoacoustic model to use in encoding. The argument must be +an integer between -1 and 4, inclusive. The higher the value, the +better the quality. The default value is 3. -@item energy_levels -(energy) Enable energy levels extensions when set to 1. The default -value is 0 (disabled). +@item energy_levels (@emph{--energy}) +Enable energy levels extensions when set to 1. The default value is +0 (disabled). -@item error_protection -(protect) Enable CRC error protection when set to 1. The default value -is 0 (disabled). +@item error_protection (@emph{--protect}) +Enable CRC error protection when set to 1. The default value is 0 +(disabled). -@item copyright -(copyright) Set MPEG audio copyright flag when set to 1. The default -value is 0 (disabled). +@item copyright (@emph{--copyright}) +Set MPEG audio copyright flag when set to 1. The default value is 0 +(disabled). -@item original -(original) Set MPEG audio original flag when set to 1. The default -value is 0 (disabled). +@item original (@emph{--original}) +Set MPEG audio original flag when set to 1. The default value is 0 +(disabled). @end table +@anchor{libvo-aacenc} @section libvo-aacenc VisualOn AAC encoder @@ -549,16 +647,19 @@ Requires the presence of the libvo-aacenc headers and library during configuration. You need to explicitly configure the build with @code{--enable-libvo-aacenc --enable-version3}. +This encoder is considered to be worse than the +@ref{aacenc,,native experimental FFmpeg AAC encoder}, according to +multiple sources. + @subsection Options The VisualOn AAC encoder only support encoding AAC-LC and up to 2 -channels. It is also CBR-only. It is considered to be worse than the -native experimental FFmpeg AAC encoder. +channels. It is also CBR-only. @table @option @item b -Bitrate. +Set bit rate in bits/s. @end table diff --git a/doc/ffmpeg-formats.texi b/doc/ffmpeg-formats.texi index 03e4f30ac3..4d9038698e 100644 --- a/doc/ffmpeg-formats.texi +++ b/doc/ffmpeg-formats.texi @@ -140,6 +140,12 @@ Use wallclock as timestamps. @item avoid_negative_ts @var{integer} (@emph{output}) Shift timestamps to make them positive. 1 enables, 0 disables, default of -1 enables when required by target format. + +@item skip_initial_bytes @var{integer} (@emph{input}) +Set number initial bytes to skip. Default is 0. + +@item correct_ts_overflow @var{integer} (@emph{input}) +Correct single timestamp overflows if set to 1. Default is 1. @end table @c man end FORMAT OPTIONS |