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Merge remote-tracking branch 'TimothyGu/release/1.2' into release/1.2

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* 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:
Michael Niedermayer
2013-10-03 01:18:14 +02:00
parent 95e26d33d7 6db67ac2a4
commit ca47aec665
2 changed files with 158 additions and 48 deletions
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197
doc/encoders.texi
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@@ -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 LAME-equivalent options follow the FFmpeg ones.
The following options are supported by the libmp3lame wrapper. The
@command{lame}-equivalent of the options are listed in parentheses.
@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
@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.
@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

9
doc/ffmpeg-formats.texi
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@@ -76,6 +76,9 @@ Enable RTP MP4A-LATM payload.
Reduce the latency introduced by optional buffering
@end table
@item seek2any @var{integer} (@emph{input})
Forces seeking to enable seek to any mode if set to 1. Default is 0.
@item analyzeduration @var{integer} (@emph{input})
Specify how many microseconds are analyzed to probe the input. A
higher value will allow to detect more accurate information, but will
@@ -142,6 +145,12 @@ 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