From: Timothy Gu <[email protected]>
---
doc/encoders.texi | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 125 insertions(+)
diff --git a/doc/encoders.texi b/doc/encoders.texi
index bbd8b87..997ef9a6 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -456,6 +456,131 @@ Selected by Encoder (default)
@end table
+@section libopus
+
+libopus Opus Interactive Audio Codec encoder wrapper.
+
+Requires the presence of the libopus headers and library during
+configuration. You need to explicitly configure the build with
+@code{--enable-libopus}.
+
+@subsection Option Mapping
+
+Most libopus options are modeled after the @command{opusenc} utility from
+opus-tools. The following is an option mapping chart describing options
+supported by the libopus wrapper, and their @command{opusenc}-equivalent
+in parentheses.
+
+@table @option
+
+@item b (@emph{bitrate})
+Set the bit rate in bits/s. avconv @option{b} option is
+expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
+kilobits/s.
+
+@item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
+Set VBR mode. avconv @option{vbr} option has the following
+valid arguments, with the their @command{opusenc} equivalent options
+in parentheses:
+
+@table @samp
+@item off (@emph{hard-cbr})
+Use constant bit rate encoding.
+
+@item on (@emph{vbr})
+Use variable bit rate encoding (the default).
+
+@item constrained (@emph{cvbr})
+Use constrained variable bit rate encoding.
+@end table
+
+@item compression_level (@emph{comp})
+Set encoding algorithm complexity. Valid options are integers in
+the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
+gives the highest quality but slowest encoding. The default is 10.
+
+@item frame_duration (@emph{framesize})
+Set maximum frame size, or duration of a frame in milliseconds. The
+argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
+frame sizes achieve lower latency but less quality at a given bitrate.
+Sizes greater than 20ms are only interesting at fairly low bitrates.
+The default for Libav is 10ms, but it is 20ms in @command{opusenc}.
+
+@item packet_loss (@emph{expect-loss})
+Set expected packet loss percentage. The default is 0.
+
+@item application (N.A.)
+Set intended application type. Valid options are listed below:
+
+@table @samp
+@item voip
+Favor improved speech intelligibility.
+@item audio
+Favor faithfulness to the input (the default).
+@item lowdelay
+Restrict to only the lowest delay modes.
+@end table
+
+@item cutoff (N.A.)
+Set cutoff bandwidth in Hz. The argument must be exactly one of the
+following: 4000, 6000, 8000, 12000, or 20000, corresponding to
+narrowband, mediumband, wideband, super wideband, and fullband
+respectively. The default is 0 (cutoff disabled).
+
+@end table
+
+@section libvorbis
+
+libvorbis encoder wrapper.
+
+Requires the presence of the libvorbisenc headers and library during
+configuration. You need to explicitly configure the build with
+@code{--enable-libvorbis}.
+
+@subsection Options
+
+The following options are supported by the libvorbis wrapper. The
+@command{oggenc}-equivalent of the options are listed in parentheses.
+
+To get a more accurate and extensive documentation of the libvorbis
+options, consult the libvorbisenc's and @command{oggenc}'s documentations.
+See @url{http://xiph.org/vorbis/},
+@url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
+
+@table @option
+@item b (@emph{-b})
+Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
+expressed in kilobits/s.
+
+@item q (@emph{-q})
+Set constant quality setting for VBR. The value should be a float
+number in the range of -1.0 to 10.0. The higher the value, the better
+the quality. The default value is @samp{3.0}.
+
+This option is valid only using the @command{avconv} command-line tool.
+For library interface users, use @option{global_quality}.
+
+@item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
+Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
+related option is expressed in kHz. The default value is @samp{0} (cutoff
+disabled).
+
+@item minrate (@emph{-m})
+Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
+expressed in kilobits/s.
+
+@item maxrate (@emph{-M})
+Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
+expressed in kilobits/s. This only has effect on ABR mode.
+
+@item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
+Set noise floor bias for impulse blocks. The value is a float number from
+-15.0 to 0.0. A negative bias instructs the encoder to pay special attention
+to the crispness of transients in the encoded audio. The tradeoff for better
+transient response is a higher bitrate.
+
+@end table
+
@section libwavpack
A wrapper providing WavPack encoding through libwavpack.
--
1.8.3.4 (Apple Git-47)
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