avfilter/af_aiir: rename options, provide gains in separate option

This way it can be also used for other format.

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

1 files changed, 11 insertions, 9 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 69c59d74a6..f6954c947c 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1067,11 +1067,14 @@ Apply an arbitrary Infinite Impulse Response filter.
 It accepts the following parameters:
 
 @table @option
-@item a
+@item z
+Set numerator/zeros coefficients.
+
+@item p
 Set denominator/poles coefficients.
 
-@item b
-Set numerator/zeros coefficients.
+@item k
+Set channels gains.
 
 @item dry_gain
 Set input gain.
@@ -1089,11 +1092,10 @@ order.
 
 Coefficients in @code{zp} format are separated by spaces and order of coefficients
 doesn't matter. Coefficients in @code{zp} format are complex numbers with @var{i}
-imaginary unit, also first number in numerator, option @var{b}, is not complex but
-real number and sets overall gain for channel.
+imaginary unit.
 
-Different coefficients can be provided for every channel, in such case
-use '|' to separate coefficients. Last provided coefficients will be
+Different coefficients and gains can be provided for every channel, in such case
+use '|' to separate coefficients or gains. Last provided coefficients will be
 used for all remaining channels.
 
 @subsection Examples
@@ -1102,13 +1104,13 @@ used for all remaining channels.
 @item
 Apply 2 pole elliptic notch at arround 5000Hz for 48000 Hz sample rate:
 @example
-aiir=b=7.957584807809675810E-1 -2.575128568908332300 3.674839853930788710 -2.57512875289799137 7.957586296317130880E-1:a=1 -2.86950072432325953 3.63022088054647218 -2.28075678147272232 6.361362326477423500E-1:f=tf
+aiir=k=1:z=7.957584807809675810E-1 -2.575128568908332300 3.674839853930788710 -2.57512875289799137 7.957586296317130880E-1:p=1 -2.86950072432325953 3.63022088054647218 -2.28075678147272232 6.361362326477423500E-1:f=tf
 @end example
 
 @item
 Same as above but in @code{zp} format:
 @example
-aiir=b=0.79575848078096756 0.80918701+0.58773007i 0.80918701-0.58773007i 0.80884700+0.58784055i 0.80884700-0.58784055i:a=0.63892345+0.59951235i 0.63892345-0.59951235i 0.79582691+0.44198673i 0.79582691-0.44198673i:f=zp
+aiir=k=0.79575848078096756:z=0.80918701+0.58773007i 0.80918701-0.58773007i 0.80884700+0.58784055i 0.80884700-0.58784055i:p=0.63892345+0.59951235i 0.63892345-0.59951235i 0.79582691+0.44198673i 0.79582691-0.44198673i:f=zp
 @end example
 @end itemize