diff --git a/doc/avconv.texi b/doc/avconv.texi index 972d13fed5..7ef415fc7d 100644 --- a/doc/avconv.texi +++ b/doc/avconv.texi @@ -1120,6 +1120,7 @@ avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext @c man end EXAMPLES @include eval.texi +@include decoders.texi @include encoders.texi @include demuxers.texi @include muxers.texi diff --git a/doc/avplay.texi b/doc/avplay.texi index 50142ab282..4d9af5f562 100644 --- a/doc/avplay.texi +++ b/doc/avplay.texi @@ -155,6 +155,7 @@ Seek to percentage in file corresponding to fraction of width. @c man end @include eval.texi +@include decoders.texi @include demuxers.texi @include muxers.texi @include indevs.texi diff --git a/doc/decoders.texi b/doc/decoders.texi new file mode 100644 index 0000000000..c3573a6315 --- /dev/null +++ b/doc/decoders.texi @@ -0,0 +1,56 @@ +@chapter Decoders +@c man begin DECODERS + +Decoders are configured elements in Libav which allow the decoding of +multimedia streams. + +When you configure your Libav build, all the supported native decoders +are enabled by default. Decoders requiring an external library must be enabled +manually via the corresponding @code{--enable-lib} option. You can list all +available decoders using the configure option @code{--list-decoders}. + +You can disable all the decoders with the configure option +@code{--disable-decoders} and selectively enable / disable single decoders +with the options @code{--enable-decoder=@var{DECODER}} / +@code{--disable-decoder=@var{DECODER}}. + +The option @code{-decoders} of the av* tools will display the list of +enabled decoders. + +@c man end DECODERS + +@chapter Audio Decoders +@c man begin AUDIO DECODERS + +A description of some of the currently available audio decoders +follows. + +@section ac3 + +AC-3 audio decoder. + +This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as +the undocumented RealAudio 3 (a.k.a. dnet). + +@subsubsection AC-3 Decoder Options + +@table @option + +@item -drc_scale @var{value} +Dynamic Range Scale Factor. The factor to apply to dynamic range values +from the AC-3 stream. This factor is applied exponentially. +There are 3 notable scale factor ranges: +@table @option +@item drc_scale == 0 +DRC disabled. Produces full range audio. +@item 0 < drc_scale <= 1 +DRC enabled. Applies a fraction of the stream DRC value. +Audio reproduction is between full range and full compression. +@item drc_scale > 1 +DRC enabled. Applies drc_scale asymmetrically. +Loud sounds are fully compressed. Soft sounds are enhanced. +@end table + +@end table + +@c man end AUDIO DECODERS