avfilter: add convolution filter

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

1 files changed, 62 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index ef2ecf4265..7f2c419aa0 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -4662,6 +4662,68 @@ For example to convert from BT.601 to SMPTE-240M, use the command:
 colormatrix=bt601:smpte240m
 @end example
 
+@section convolution
+
+Apply convolution 3x3 or 5x5 filter.
+
+The filter accepts the following options:
+
+@table @option
+@item 0m
+@item 1m
+@item 2m
+@item 3m
+Set matrix for each plane.
+Matrix is sequence of 9 or 25 signed integers.
+
+@item 0rdiv
+@item 1rdiv
+@item 2rdiv
+@item 3rdiv
+Set multiplier for calculated value for each plane.
+
+@item 0bias
+@item 1bias
+@item 2bias
+@item 3bias
+Set bias for each plane. This value is added to the result of the multiplication.
+Useful for making the overall image brighter or darker. Default is 0.0.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply sharpen:
+@example
+convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"
+@end example
+
+@item
+Apply blur:
+@example
+convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"
+@end example
+
+@item
+Apply edge enhance:
+@example
+convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"
+@end example
+
+@item
+Apply edge detect:
+@example
+convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"
+@end example
+
+@item
+Apply emboss:
+@example
+convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"
+@end example
+@end itemize
+
 @section copy
 
 Copy the input source unchanged to the output. This is mainly useful for