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-rw-r--r--doc/filters.texi37
1 files changed, 14 insertions, 23 deletions
diff --git a/doc/filters.texi b/doc/filters.texi
index d83a3fb91e..ffe9a424a8 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1794,33 +1794,24 @@ Set wet gain. This sets final output gain.
Set Impulse Response filter length. Default is 1, which means whole IR is processed.
@item gtype
-Enable applying gain measured from power of IR.
+This option is deprecated, and does nothing.
-Set which approach to use for auto gain measurement.
+@item irnorm
+Set norm to be applied to IR coefficients before filtering.
+Allowed range is from @var{-1} to @var{2}.
+IR coefficients are normalized with calculated vector norm set by this option.
+For negative values, no norm is calculated, and IR coefficients are not modified at all.
+Default is @var{1}.
-@table @option
-@item none
-Do not apply any gain.
-
-@item peak
-select peak gain, very conservative approach. This is default value.
-
-@item dc
-select DC gain, limited application.
-
-@item gn
-select gain to noise approach, this is most popular one.
-
-@item ac
-select AC gain.
-
-@item rms
-select RMS gain.
-@end table
+@item irlink
+For multichannel IR if this option is set to @var{true}. All IR channels will be
+normalized with maximal measured gain of all IR channels coefficients as set by @code{irnorm} option.
+When disabled, all IR coefficients in each IR channel will be normalized independently.
+Default is @var{true}.
@item irgain
Set gain to be applied to IR coefficients before filtering.
-Allowed range is 0 to 1. This gain is applied after any gain applied with @var{gtype} option.
+Allowed range is 0 to 1. This gain is applied after any gain applied with @var{irnorm} option.
@item irfmt
Set format of IR stream. Can be @code{mono} or @code{input}.
@@ -1899,7 +1890,7 @@ ffmpeg -i input.wav -i middle_tunnel_1way_mono.wav -lavfi afir output.wav
Apply true stereo processing given input stereo stream, and two stereo impulse responses for left and right channel,
the impulse response files are files with names l_ir.wav and r_ir.wav:
@example
-"pan=4C|c0=FL|c1=FL|c2=FR|c3=FR[a];amovie=l_ir.wav[LIR];amovie=r_ir.wav[RIR];[LIR][RIR]amerge[ir];[a][ir]afir=irfmt=input:gtype=gn:irgain=-5dB,pan=stereo|FL<c0+c2|FR<c1+c3"
+"pan=4C|c0=FL|c1=FL|c2=FR|c3=FR[a];amovie=l_ir.wav[LIR];amovie=r_ir.wav[RIR];[LIR][RIR]amerge[ir];[a][ir]afir=irfmt=input:irgain=-5dB,pan=stereo|FL<c0+c2|FR<c1+c3"
@end example
@end itemize