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author | John Stebbins <stebbins@jetheaddev.com> | 2014-01-26 18:49:10 +0400 |
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committer | Tim Walker <tdskywalker@gmail.com> | 2014-01-30 02:27:18 +0400 |
commit | a17ab0e46a9fec7c31cc1be363828184c6ecebf7 (patch) | |
tree | 5b8f147c6f7096e36714d4288280f271cfe76833 /doc/decoders.texi | |
parent | 23d461fe8714a20ee5e6929f22c61512fdda568e (diff) |
doc: add decoders.texi
Only documents ac3 decoder options at this point.
Diffstat (limited to 'doc/decoders.texi')
-rw-r--r-- | doc/decoders.texi | 56 |
1 files changed, 56 insertions, 0 deletions
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 |