[FFmpeg-devel] [PATCH 2/2] doc: document cutoff option to ac3 and adjust the option's global documentation

Moritz Barsnick barsnick at gmx.net
Fri Dec 30 19:08:14 EET 2016

cutoff is implemented as an option global to lavc, but supported only
by a few encoders. This fact is now reflected in its documentation. ac3's
support of this option is added for completeness.

Signed-off-by: Moritz Barsnick <barsnick at gmx.net>
 doc/codecs.texi   | 3 ++-
 doc/encoders.texi | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/doc/codecs.texi b/doc/codecs.texi
index 9a3a56d..6093605 100644
--- a/doc/codecs.texi
+++ b/doc/codecs.texi
@@ -138,7 +138,8 @@ Set audio sampling rate (in Hz).
 Set number of audio channels.
 @item cutoff @var{integer} (@emph{encoding,audio})
-Set cutoff bandwidth.
+Set cutoff bandwidth. (Supported only by selected encoders, see
+their respective documentation sections.)
 @item frame_size @var{integer} (@emph{encoding,audio})
 Set audio frame size.
diff --git a/doc/encoders.texi b/doc/encoders.texi
index 5e311cb..8137465 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -488,6 +488,10 @@ is an optional AC-3 feature that increases quality by selectively encoding
 the left/right channels as mid/side. This option is enabled by default, and it
 is highly recommended that it be left as enabled except for testing purposes.
+ at item cutoff @var{frequency}
+Set lowpass cutoff frequency. If unspecified, the encoder selects a default
+determined by various other encoding parameters.
 @end table
 @subsection Floating-Point-Only AC-3 Encoding Options

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