avfilter: add stereowiden filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 4958374..9b6e6ff 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2394,6 +2394,33 @@ silenceremove=1:5:0.02
 @end example
 @end itemize
 
+@section stereowiden
+
+This filter enhance the stereo effect by suppressing signal common to both
+channels and by delaying the signal of left into right and vice versa,
+thereby widening the stereo effect.
+
+The filter accepts the following options:
+
+@table @option
+@item delay
+Time in milliseconds of the delay of left signal into right and vice versa.
+Default is 20 milliseconds.
+
+@item feedback
+Amount of gain in delayed signal into right and vice versa. Gives a delay
+effect of left signal in right output and vice versa which gives widening
+effect. Default is 0.3.
+
+@item crossfeed
+Cross feed of left into right with inverted phase. This helps in suppressing
+the mono. If the value is 1 it will cancel all the signal common to both
+channels. Default is 0.3.
+
+@item drymix
+Set level of input signal of original channel. Default is 0.8.
+@end table
+
 @section treble
 
 Boost or cut treble (upper) frequencies of the audio using a two-pole